1/*
2  Madge Horizon ATM Adapter driver.
3  Copyright (C) 1995-1999  Madge Networks Ltd.
4
5  This program is free software; you can redistribute it and/or modify
6  it under the terms of the GNU General Public License as published by
7  the Free Software Foundation; either version 2 of the License, or
8  (at your option) any later version.
9
10  This program is distributed in the hope that it will be useful,
11  but WITHOUT ANY WARRANTY; without even the implied warranty of
12  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  GNU General Public License for more details.
14
15  You should have received a copy of the GNU General Public License
16  along with this program; if not, write to the Free Software
17  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18
19  The GNU GPL is contained in /usr/doc/copyright/GPL on a Debian
20  system and in the file COPYING in the Linux kernel source.
21*/
22
23/*
24  IMPORTANT NOTE: Madge Networks no longer makes the adapters
25  supported by this driver and makes no commitment to maintain it.
26*/
27
28#include <linux/module.h>
29#include <linux/kernel.h>
30#include <linux/mm.h>
31#include <linux/pci.h>
32#include <linux/errno.h>
33#include <linux/atm.h>
34#include <linux/atmdev.h>
35#include <linux/sonet.h>
36#include <linux/skbuff.h>
37#include <linux/time.h>
38#include <linux/delay.h>
39#include <linux/uio.h>
40#include <linux/init.h>
41#include <linux/interrupt.h>
42#include <linux/ioport.h>
43#include <linux/wait.h>
44#include <linux/slab.h>
45
46#include <asm/io.h>
47#include <linux/atomic.h>
48#include <asm/uaccess.h>
49#include <asm/string.h>
50#include <asm/byteorder.h>
51
52#include "horizon.h"
53
54#define maintainer_string "Giuliano Procida at Madge Networks <gprocida@madge.com>"
55#define description_string "Madge ATM Horizon [Ultra] driver"
56#define version_string "1.2.1"
57
58static inline void __init show_version (void) {
59  printk ("%s version %s\n", description_string, version_string);
60}
61
62/*
63
64  CREDITS
65
66  Driver and documentation by:
67
68  Chris Aston        Madge Networks
69  Giuliano Procida   Madge Networks
70  Simon Benham       Madge Networks
71  Simon Johnson      Madge Networks
72  Various Others     Madge Networks
73
74  Some inspiration taken from other drivers by:
75
76  Alexandru Cucos    UTBv
77  Kari Mettinen      University of Helsinki
78  Werner Almesberger EPFL LRC
79
80  Theory of Operation
81
82  I Hardware, detection, initialisation and shutdown.
83
84  1. Supported Hardware
85
86  This driver should handle all variants of the PCI Madge ATM adapters
87  with the Horizon chipset. These are all PCI cards supporting PIO, BM
88  DMA and a form of MMIO (registers only, not internal RAM).
89
90  The driver is only known to work with SONET and UTP Horizon Ultra
91  cards at 155Mb/s. However, code is in place to deal with both the
92  original Horizon and 25Mb/s operation.
93
94  There are two revisions of the Horizon ASIC: the original and the
95  Ultra. Details of hardware bugs are in section III.
96
97  The ASIC version can be distinguished by chip markings but is NOT
98  indicated by the PCI revision (all adapters seem to have PCI rev 1).
99
100  I believe that:
101
102  Horizon       => Collage  25 PCI Adapter (UTP and STP)
103  Horizon Ultra => Collage 155 PCI Client (UTP or SONET)
104  Ambassador x  => Collage 155 PCI Server (completely different)
105
106  Horizon (25Mb/s) is fitted with UTP and STP connectors. It seems to
107  have a Madge B154 plus glue logic serializer. I have also found a
108  really ancient version of this with slightly different glue. It
109  comes with the revision 0 (140-025-01) ASIC.
110
111  Horizon Ultra (155Mb/s) is fitted with either a Pulse Medialink
112  output (UTP) or an HP HFBR 5205 output (SONET). It has either
113  Madge's SAMBA framer or a SUNI-lite device (early versions). It
114  comes with the revision 1 (140-027-01) ASIC.
115
116  2. Detection
117
118  All Horizon-based cards present with the same PCI Vendor and Device
119  IDs. The standard Linux 2.2 PCI API is used to locate any cards and
120  to enable bus-mastering (with appropriate latency).
121
122  ATM_LAYER_STATUS in the control register distinguishes between the
123  two possible physical layers (25 and 155). It is not clear whether
124  the 155 cards can also operate at 25Mbps. We rely on the fact that a
125  card operates at 155 if and only if it has the newer Horizon Ultra
126  ASIC.
127
128  For 155 cards the two possible framers are probed for and then set
129  up for loop-timing.
130
131  3. Initialisation
132
133  The card is reset and then put into a known state. The physical
134  layer is configured for normal operation at the appropriate speed;
135  in the case of the 155 cards, the framer is initialised with
136  line-based timing; the internal RAM is zeroed and the allocation of
137  buffers for RX and TX is made; the Burnt In Address is read and
138  copied to the ATM ESI; various policy settings for RX (VPI bits,
139  unknown VCs, oam cells) are made. Ideally all policy items should be
140  configurable at module load (if not actually on-demand), however,
141  only the vpi vs vci bit allocation can be specified at insmod.
142
143  4. Shutdown
144
145  This is in response to module_cleaup. No VCs are in use and the card
146  should be idle; it is reset.
147
148  II Driver software (as it should be)
149
150  0. Traffic Parameters
151
152  The traffic classes (not an enumeration) are currently: ATM_NONE (no
153  traffic), ATM_UBR, ATM_CBR, ATM_VBR and ATM_ABR, ATM_ANYCLASS
154  (compatible with everything). Together with (perhaps only some of)
155  the following items they make up the traffic specification.
156
157  struct atm_trafprm {
158    unsigned char traffic_class; traffic class (ATM_UBR, ...)
159    int           max_pcr;       maximum PCR in cells per second
160    int           pcr;           desired PCR in cells per second
161    int           min_pcr;       minimum PCR in cells per second
162    int           max_cdv;       maximum CDV in microseconds
163    int           max_sdu;       maximum SDU in bytes
164  };
165
166  Note that these denote bandwidth available not bandwidth used; the
167  possibilities according to ATMF are:
168
169  Real Time (cdv and max CDT given)
170
171  CBR(pcr)             pcr bandwidth always available
172  rtVBR(pcr,scr,mbs)   scr bandwidth always available, up to pcr at mbs too
173
174  Non Real Time
175
176  nrtVBR(pcr,scr,mbs)  scr bandwidth always available, up to pcr at mbs too
177  UBR()
178  ABR(mcr,pcr)         mcr bandwidth always available, up to pcr (depending) too
179
180  mbs is max burst size (bucket)
181  pcr and scr have associated cdvt values
182  mcr is like scr but has no cdtv
183  cdtv may differ at each hop
184
185  Some of the above items are qos items (as opposed to traffic
186  parameters). We have nothing to do with qos. All except ABR can have
187  their traffic parameters converted to GCRA parameters. The GCRA may
188  be implemented as a (real-number) leaky bucket. The GCRA can be used
189  in complicated ways by switches and in simpler ways by end-stations.
190  It can be used both to filter incoming cells and shape out-going
191  cells.
192
193  ATM Linux actually supports:
194
195  ATM_NONE() (no traffic in this direction)
196  ATM_UBR(max_frame_size)
197  ATM_CBR(max/min_pcr, max_cdv, max_frame_size)
198
199  0 or ATM_MAX_PCR are used to indicate maximum available PCR
200
201  A traffic specification consists of the AAL type and separate
202  traffic specifications for either direction. In ATM Linux it is:
203
204  struct atm_qos {
205  struct atm_trafprm txtp;
206  struct atm_trafprm rxtp;
207  unsigned char aal;
208  };
209
210  AAL types are:
211
212  ATM_NO_AAL    AAL not specified
213  ATM_AAL0      "raw" ATM cells
214  ATM_AAL1      AAL1 (CBR)
215  ATM_AAL2      AAL2 (VBR)
216  ATM_AAL34     AAL3/4 (data)
217  ATM_AAL5      AAL5 (data)
218  ATM_SAAL      signaling AAL
219
220  The Horizon has support for AAL frame types: 0, 3/4 and 5. However,
221  it does not implement AAL 3/4 SAR and it has a different notion of
222  "raw cell" to ATM Linux's (48 bytes vs. 52 bytes) so neither are
223  supported by this driver.
224
225  The Horizon has limited support for ABR (including UBR), VBR and
226  CBR. Each TX channel has a bucket (containing up to 31 cell units)
227  and two timers (PCR and SCR) associated with it that can be used to
228  govern cell emissions and host notification (in the case of ABR this
229  is presumably so that RM cells may be emitted at appropriate times).
230  The timers may either be disabled or may be set to any of 240 values
231  (determined by the clock crystal, a fixed (?) per-device divider, a
232  configurable divider and a configurable timer preload value).
233
234  At the moment only UBR and CBR are supported by the driver. VBR will
235  be supported as soon as ATM for Linux supports it. ABR support is
236  very unlikely as RM cell handling is completely up to the driver.
237
238  1. TX (TX channel setup and TX transfer)
239
240  The TX half of the driver owns the TX Horizon registers. The TX
241  component in the IRQ handler is the BM completion handler. This can
242  only be entered when tx_busy is true (enforced by hardware). The
243  other TX component can only be entered when tx_busy is false
244  (enforced by driver). So TX is single-threaded.
245
246  Apart from a minor optimisation to not re-select the last channel,
247  the TX send component works as follows:
248
249  Atomic test and set tx_busy until we succeed; we should implement
250  some sort of timeout so that tx_busy will never be stuck at true.
251
252  If no TX channel is set up for this VC we wait for an idle one (if
253  necessary) and set it up.
254
255  At this point we have a TX channel ready for use. We wait for enough
256  buffers to become available then start a TX transmit (set the TX
257  descriptor, schedule transfer, exit).
258
259  The IRQ component handles TX completion (stats, free buffer, tx_busy
260  unset, exit). We also re-schedule further transfers for the same
261  frame if needed.
262
263  TX setup in more detail:
264
265  TX open is a nop, the relevant information is held in the hrz_vcc
266  (vcc->dev_data) structure and is "cached" on the card.
267
268  TX close gets the TX lock and clears the channel from the "cache".
269
270  2. RX (Data Available and RX transfer)
271
272  The RX half of the driver owns the RX registers. There are two RX
273  components in the IRQ handler: the data available handler deals with
274  fresh data that has arrived on the card, the BM completion handler
275  is very similar to the TX completion handler. The data available
276  handler grabs the rx_lock and it is only released once the data has
277  been discarded or completely transferred to the host. The BM
278  completion handler only runs when the lock is held; the data
279  available handler is locked out over the same period.
280
281  Data available on the card triggers an interrupt. If the data is not
282  suitable for our existing RX channels or we cannot allocate a buffer
283  it is flushed. Otherwise an RX receive is scheduled. Multiple RX
284  transfers may be scheduled for the same frame.
285
286  RX setup in more detail:
287
288  RX open...
289  RX close...
290
291  III Hardware Bugs
292
293  0. Byte vs Word addressing of adapter RAM.
294
295  A design feature; see the .h file (especially the memory map).
296
297  1. Bus Master Data Transfers (original Horizon only, fixed in Ultra)
298
299  The host must not start a transmit direction transfer at a
300  non-four-byte boundary in host memory. Instead the host should
301  perform a byte, or a two byte, or one byte followed by two byte
302  transfer in order to start the rest of the transfer on a four byte
303  boundary. RX is OK.
304
305  Simultaneous transmit and receive direction bus master transfers are
306  not allowed.
307
308  The simplest solution to these two is to always do PIO (never DMA)
309  in the TX direction on the original Horizon. More complicated
310  solutions are likely to hurt my brain.
311
312  2. Loss of buffer on close VC
313
314  When a VC is being closed, the buffer associated with it is not
315  returned to the pool. The host must store the reference to this
316  buffer and when opening a new VC then give it to that new VC.
317
318  The host intervention currently consists of stacking such a buffer
319  pointer at VC close and checking the stack at VC open.
320
321  3. Failure to close a VC
322
323  If a VC is currently receiving a frame then closing the VC may fail
324  and the frame continues to be received.
325
326  The solution is to make sure any received frames are flushed when
327  ready. This is currently done just before the solution to 2.
328
329  4. PCI bus (original Horizon only, fixed in Ultra)
330
331  Reading from the data port prior to initialisation will hang the PCI
332  bus. Just don't do that then! We don't.
333
334  IV To Do List
335
336  . Timer code may be broken.
337
338  . Allow users to specify buffer allocation split for TX and RX.
339
340  . Deal once and for all with buggy VC close.
341
342  . Handle interrupted and/or non-blocking operations.
343
344  . Change some macros to functions and move from .h to .c.
345
346  . Try to limit the number of TX frames each VC may have queued, in
347    order to reduce the chances of TX buffer exhaustion.
348
349  . Implement VBR (bucket and timers not understood) and ABR (need to
350    do RM cells manually); also no Linux support for either.
351
352  . Implement QoS changes on open VCs (involves extracting parts of VC open
353    and close into separate functions and using them to make changes).
354
355*/
356
357/********** globals **********/
358
359static void do_housekeeping (unsigned long arg);
360
361static unsigned short debug = 0;
362static unsigned short vpi_bits = 0;
363static int max_tx_size = 9000;
364static int max_rx_size = 9000;
365static unsigned char pci_lat = 0;
366
367/********** access functions **********/
368
369/* Read / Write Horizon registers */
370static inline void wr_regl (const hrz_dev * dev, unsigned char reg, u32 data) {
371  outl (cpu_to_le32 (data), dev->iobase + reg);
372}
373
374static inline u32 rd_regl (const hrz_dev * dev, unsigned char reg) {
375  return le32_to_cpu (inl (dev->iobase + reg));
376}
377
378static inline void wr_regw (const hrz_dev * dev, unsigned char reg, u16 data) {
379  outw (cpu_to_le16 (data), dev->iobase + reg);
380}
381
382static inline u16 rd_regw (const hrz_dev * dev, unsigned char reg) {
383  return le16_to_cpu (inw (dev->iobase + reg));
384}
385
386static inline void wrs_regb (const hrz_dev * dev, unsigned char reg, void * addr, u32 len) {
387  outsb (dev->iobase + reg, addr, len);
388}
389
390static inline void rds_regb (const hrz_dev * dev, unsigned char reg, void * addr, u32 len) {
391  insb (dev->iobase + reg, addr, len);
392}
393
394/* Read / Write to a given address in Horizon buffer memory.
395   Interrupts must be disabled between the address register and data
396   port accesses as these must form an atomic operation. */
397static inline void wr_mem (const hrz_dev * dev, HDW * addr, u32 data) {
398  // wr_regl (dev, MEM_WR_ADDR_REG_OFF, (u32) addr);
399  wr_regl (dev, MEM_WR_ADDR_REG_OFF, (addr - (HDW *) 0) * sizeof(HDW));
400  wr_regl (dev, MEMORY_PORT_OFF, data);
401}
402
403static inline u32 rd_mem (const hrz_dev * dev, HDW * addr) {
404  // wr_regl (dev, MEM_RD_ADDR_REG_OFF, (u32) addr);
405  wr_regl (dev, MEM_RD_ADDR_REG_OFF, (addr - (HDW *) 0) * sizeof(HDW));
406  return rd_regl (dev, MEMORY_PORT_OFF);
407}
408
409static inline void wr_framer (const hrz_dev * dev, u32 addr, u32 data) {
410  wr_regl (dev, MEM_WR_ADDR_REG_OFF, (u32) addr | 0x80000000);
411  wr_regl (dev, MEMORY_PORT_OFF, data);
412}
413
414static inline u32 rd_framer (const hrz_dev * dev, u32 addr) {
415  wr_regl (dev, MEM_RD_ADDR_REG_OFF, (u32) addr | 0x80000000);
416  return rd_regl (dev, MEMORY_PORT_OFF);
417}
418
419/********** specialised access functions **********/
420
421/* RX */
422
423static inline void FLUSH_RX_CHANNEL (hrz_dev * dev, u16 channel) {
424  wr_regw (dev, RX_CHANNEL_PORT_OFF, FLUSH_CHANNEL | channel);
425  return;
426}
427
428static void WAIT_FLUSH_RX_COMPLETE (hrz_dev * dev) {
429  while (rd_regw (dev, RX_CHANNEL_PORT_OFF) & FLUSH_CHANNEL)
430    ;
431  return;
432}
433
434static inline void SELECT_RX_CHANNEL (hrz_dev * dev, u16 channel) {
435  wr_regw (dev, RX_CHANNEL_PORT_OFF, channel);
436  return;
437}
438
439static void WAIT_UPDATE_COMPLETE (hrz_dev * dev) {
440  while (rd_regw (dev, RX_CHANNEL_PORT_OFF) & RX_CHANNEL_UPDATE_IN_PROGRESS)
441    ;
442  return;
443}
444
445/* TX */
446
447static inline void SELECT_TX_CHANNEL (hrz_dev * dev, u16 tx_channel) {
448  wr_regl (dev, TX_CHANNEL_PORT_OFF, tx_channel);
449  return;
450}
451
452/* Update or query one configuration parameter of a particular channel. */
453
454static inline void update_tx_channel_config (hrz_dev * dev, short chan, u8 mode, u16 value) {
455  wr_regw (dev, TX_CHANNEL_CONFIG_COMMAND_OFF,
456	   chan * TX_CHANNEL_CONFIG_MULT | mode);
457    wr_regw (dev, TX_CHANNEL_CONFIG_DATA_OFF, value);
458    return;
459}
460
461/********** dump functions **********/
462
463static inline void dump_skb (char * prefix, unsigned int vc, struct sk_buff * skb) {
464#ifdef DEBUG_HORIZON
465  unsigned int i;
466  unsigned char * data = skb->data;
467  PRINTDB (DBG_DATA, "%s(%u) ", prefix, vc);
468  for (i=0; i<skb->len && i < 256;i++)
469    PRINTDM (DBG_DATA, "%02x ", data[i]);
470  PRINTDE (DBG_DATA,"");
471#else
472  (void) prefix;
473  (void) vc;
474  (void) skb;
475#endif
476  return;
477}
478
479static inline void dump_regs (hrz_dev * dev) {
480#ifdef DEBUG_HORIZON
481  PRINTD (DBG_REGS, "CONTROL 0: %#x", rd_regl (dev, CONTROL_0_REG));
482  PRINTD (DBG_REGS, "RX CONFIG: %#x", rd_regw (dev, RX_CONFIG_OFF));
483  PRINTD (DBG_REGS, "TX CONFIG: %#x", rd_regw (dev, TX_CONFIG_OFF));
484  PRINTD (DBG_REGS, "TX STATUS: %#x", rd_regw (dev, TX_STATUS_OFF));
485  PRINTD (DBG_REGS, "IRQ ENBLE: %#x", rd_regl (dev, INT_ENABLE_REG_OFF));
486  PRINTD (DBG_REGS, "IRQ SORCE: %#x", rd_regl (dev, INT_SOURCE_REG_OFF));
487#else
488  (void) dev;
489#endif
490  return;
491}
492
493static inline void dump_framer (hrz_dev * dev) {
494#ifdef DEBUG_HORIZON
495  unsigned int i;
496  PRINTDB (DBG_REGS, "framer registers:");
497  for (i = 0; i < 0x10; ++i)
498    PRINTDM (DBG_REGS, " %02x", rd_framer (dev, i));
499  PRINTDE (DBG_REGS,"");
500#else
501  (void) dev;
502#endif
503  return;
504}
505
506/********** VPI/VCI <-> (RX) channel conversions **********/
507
508/* RX channels are 10 bit integers, these fns are quite paranoid */
509
510static inline int vpivci_to_channel (u16 * channel, const short vpi, const int vci) {
511  unsigned short vci_bits = 10 - vpi_bits;
512  if (0 <= vpi && vpi < 1<<vpi_bits && 0 <= vci && vci < 1<<vci_bits) {
513    *channel = vpi<<vci_bits | vci;
514    return *channel ? 0 : -EINVAL;
515  }
516  return -EINVAL;
517}
518
519/********** decode RX queue entries **********/
520
521static inline u16 rx_q_entry_to_length (u32 x) {
522  return x & RX_Q_ENTRY_LENGTH_MASK;
523}
524
525static inline u16 rx_q_entry_to_rx_channel (u32 x) {
526  return (x>>RX_Q_ENTRY_CHANNEL_SHIFT) & RX_CHANNEL_MASK;
527}
528
529/* Cell Transmit Rate Values
530 *
531 * the cell transmit rate (cells per sec) can be set to a variety of
532 * different values by specifying two parameters: a timer preload from
533 * 1 to 16 (stored as 0 to 15) and a clock divider (2 to the power of
534 * an exponent from 0 to 14; the special value 15 disables the timer).
535 *
536 * cellrate = baserate / (preload * 2^divider)
537 *
538 * The maximum cell rate that can be specified is therefore just the
539 * base rate. Halving the preload is equivalent to adding 1 to the
540 * divider and so values 1 to 8 of the preload are redundant except
541 * in the case of a maximal divider (14).
542 *
543 * Given a desired cell rate, an algorithm to determine the preload
544 * and divider is:
545 *
546 * a) x = baserate / cellrate, want p * 2^d = x (as far as possible)
547 * b) if x > 16 * 2^14 then set p = 16, d = 14 (min rate), done
548 *    if x <= 16 then set p = x, d = 0 (high rates), done
549 * c) now have 16 < x <= 2^18, or 1 < x/16 <= 2^14 and we want to
550 *    know n such that 2^(n-1) < x/16 <= 2^n, so slide a bit until
551 *    we find the range (n will be between 1 and 14), set d = n
552 * d) Also have 8 < x/2^n <= 16, so set p nearest x/2^n
553 *
554 * The algorithm used below is a minor variant of the above.
555 *
556 * The base rate is derived from the oscillator frequency (Hz) using a
557 * fixed divider:
558 *
559 * baserate = freq / 32 in the case of some Unknown Card
560 * baserate = freq / 8  in the case of the Horizon        25
561 * baserate = freq / 8  in the case of the Horizon Ultra 155
562 *
563 * The Horizon cards have oscillators and base rates as follows:
564 *
565 * Card               Oscillator  Base Rate
566 * Unknown Card       33 MHz      1.03125 MHz (33 MHz = PCI freq)
567 * Horizon        25  32 MHz      4       MHz
568 * Horizon Ultra 155  40 MHz      5       MHz
569 *
570 * The following defines give the base rates in Hz. These were
571 * previously a factor of 100 larger, no doubt someone was using
572 * cps*100.
573 */
574
575#define BR_UKN 1031250l
576#define BR_HRZ 4000000l
577#define BR_ULT 5000000l
578
579// d is an exponent
580#define CR_MIND 0
581#define CR_MAXD 14
582
583// p ranges from 1 to a power of 2
584#define CR_MAXPEXP 4
585
586static int make_rate (const hrz_dev * dev, u32 c, rounding r,
587		      u16 * bits, unsigned int * actual)
588{
589	// note: rounding the rate down means rounding 'p' up
590	const unsigned long br = test_bit(ultra, &dev->flags) ? BR_ULT : BR_HRZ;
591
592	u32 div = CR_MIND;
593	u32 pre;
594
595	// br_exp and br_man are used to avoid overflowing (c*maxp*2^d) in
596	// the tests below. We could think harder about exact possibilities
597	// of failure...
598
599	unsigned long br_man = br;
600	unsigned int br_exp = 0;
601
602	PRINTD (DBG_QOS|DBG_FLOW, "make_rate b=%lu, c=%u, %s", br, c,
603		r == round_up ? "up" : r == round_down ? "down" : "nearest");
604
605	// avoid div by zero
606	if (!c) {
607		PRINTD (DBG_QOS|DBG_ERR, "zero rate is not allowed!");
608		return -EINVAL;
609	}
610
611	while (br_exp < CR_MAXPEXP + CR_MIND && (br_man % 2 == 0)) {
612		br_man = br_man >> 1;
613		++br_exp;
614	}
615	// (br >>br_exp) <<br_exp == br and
616	// br_exp <= CR_MAXPEXP+CR_MIND
617
618	if (br_man <= (c << (CR_MAXPEXP+CR_MIND-br_exp))) {
619		// Equivalent to: B <= (c << (MAXPEXP+MIND))
620		// take care of rounding
621		switch (r) {
622			case round_down:
623				pre = DIV_ROUND_UP(br, c<<div);
624				// but p must be non-zero
625				if (!pre)
626					pre = 1;
627				break;
628			case round_nearest:
629				pre = DIV_ROUND_CLOSEST(br, c<<div);
630				// but p must be non-zero
631				if (!pre)
632					pre = 1;
633				break;
634			default:	/* round_up */
635				pre = br/(c<<div);
636				// but p must be non-zero
637				if (!pre)
638					return -EINVAL;
639		}
640		PRINTD (DBG_QOS, "A: p=%u, d=%u", pre, div);
641		goto got_it;
642	}
643
644	// at this point we have
645	// d == MIND and (c << (MAXPEXP+MIND)) < B
646	while (div < CR_MAXD) {
647		div++;
648		if (br_man <= (c << (CR_MAXPEXP+div-br_exp))) {
649			// Equivalent to: B <= (c << (MAXPEXP+d))
650			// c << (MAXPEXP+d-1) < B <= c << (MAXPEXP+d)
651			// 1 << (MAXPEXP-1) < B/2^d/c <= 1 << MAXPEXP
652			// MAXP/2 < B/c2^d <= MAXP
653			// take care of rounding
654			switch (r) {
655				case round_down:
656					pre = DIV_ROUND_UP(br, c<<div);
657					break;
658				case round_nearest:
659					pre = DIV_ROUND_CLOSEST(br, c<<div);
660					break;
661				default: /* round_up */
662					pre = br/(c<<div);
663			}
664			PRINTD (DBG_QOS, "B: p=%u, d=%u", pre, div);
665			goto got_it;
666		}
667	}
668	// at this point we have
669	// d == MAXD and (c << (MAXPEXP+MAXD)) < B
670	// but we cannot go any higher
671	// take care of rounding
672	if (r == round_down)
673		return -EINVAL;
674	pre = 1 << CR_MAXPEXP;
675	PRINTD (DBG_QOS, "C: p=%u, d=%u", pre, div);
676got_it:
677	// paranoia
678	if (div > CR_MAXD || (!pre) || pre > 1<<CR_MAXPEXP) {
679		PRINTD (DBG_QOS, "set_cr internal failure: d=%u p=%u",
680			div, pre);
681		return -EINVAL;
682	} else {
683		if (bits)
684			*bits = (div<<CLOCK_SELECT_SHIFT) | (pre-1);
685		if (actual) {
686			*actual = DIV_ROUND_UP(br, pre<<div);
687			PRINTD (DBG_QOS, "actual rate: %u", *actual);
688		}
689		return 0;
690	}
691}
692
693static int make_rate_with_tolerance (const hrz_dev * dev, u32 c, rounding r, unsigned int tol,
694				     u16 * bit_pattern, unsigned int * actual) {
695  unsigned int my_actual;
696
697  PRINTD (DBG_QOS|DBG_FLOW, "make_rate_with_tolerance c=%u, %s, tol=%u",
698	  c, (r == round_up) ? "up" : (r == round_down) ? "down" : "nearest", tol);
699
700  if (!actual)
701    // actual rate is not returned
702    actual = &my_actual;
703
704  if (make_rate (dev, c, round_nearest, bit_pattern, actual))
705    // should never happen as round_nearest always succeeds
706    return -1;
707
708  if (c - tol <= *actual && *actual <= c + tol)
709    // within tolerance
710    return 0;
711  else
712    // intolerant, try rounding instead
713    return make_rate (dev, c, r, bit_pattern, actual);
714}
715
716/********** Listen on a VC **********/
717
718static int hrz_open_rx (hrz_dev * dev, u16 channel) {
719  // is there any guarantee that we don't get two simulataneous
720  // identical calls of this function from different processes? yes
721  // rate_lock
722  unsigned long flags;
723  u32 channel_type; // u16?
724
725  u16 buf_ptr = RX_CHANNEL_IDLE;
726
727  rx_ch_desc * rx_desc = &memmap->rx_descs[channel];
728
729  PRINTD (DBG_FLOW, "hrz_open_rx %x", channel);
730
731  spin_lock_irqsave (&dev->mem_lock, flags);
732  channel_type = rd_mem (dev, &rx_desc->wr_buf_type) & BUFFER_PTR_MASK;
733  spin_unlock_irqrestore (&dev->mem_lock, flags);
734
735  // very serious error, should never occur
736  if (channel_type != RX_CHANNEL_DISABLED) {
737    PRINTD (DBG_ERR|DBG_VCC, "RX channel for VC already open");
738    return -EBUSY; // clean up?
739  }
740
741  // Give back spare buffer
742  if (dev->noof_spare_buffers) {
743    buf_ptr = dev->spare_buffers[--dev->noof_spare_buffers];
744    PRINTD (DBG_VCC, "using a spare buffer: %u", buf_ptr);
745    // should never occur
746    if (buf_ptr == RX_CHANNEL_DISABLED || buf_ptr == RX_CHANNEL_IDLE) {
747      // but easy to recover from
748      PRINTD (DBG_ERR|DBG_VCC, "bad spare buffer pointer, using IDLE");
749      buf_ptr = RX_CHANNEL_IDLE;
750    }
751  } else {
752    PRINTD (DBG_VCC, "using IDLE buffer pointer");
753  }
754
755  // Channel is currently disabled so change its status to idle
756
757  // do we really need to save the flags again?
758  spin_lock_irqsave (&dev->mem_lock, flags);
759
760  wr_mem (dev, &rx_desc->wr_buf_type,
761	  buf_ptr | CHANNEL_TYPE_AAL5 | FIRST_CELL_OF_AAL5_FRAME);
762  if (buf_ptr != RX_CHANNEL_IDLE)
763    wr_mem (dev, &rx_desc->rd_buf_type, buf_ptr);
764
765  spin_unlock_irqrestore (&dev->mem_lock, flags);
766
767  // rxer->rate = make_rate (qos->peak_cells);
768
769  PRINTD (DBG_FLOW, "hrz_open_rx ok");
770
771  return 0;
772}
773
774#if 0
775/********** change vc rate for a given vc **********/
776
777static void hrz_change_vc_qos (ATM_RXER * rxer, MAAL_QOS * qos) {
778  rxer->rate = make_rate (qos->peak_cells);
779}
780#endif
781
782/********** free an skb (as per ATM device driver documentation) **********/
783
784static void hrz_kfree_skb (struct sk_buff * skb) {
785  if (ATM_SKB(skb)->vcc->pop) {
786    ATM_SKB(skb)->vcc->pop (ATM_SKB(skb)->vcc, skb);
787  } else {
788    dev_kfree_skb_any (skb);
789  }
790}
791
792/********** cancel listen on a VC **********/
793
794static void hrz_close_rx (hrz_dev * dev, u16 vc) {
795  unsigned long flags;
796
797  u32 value;
798
799  u32 r1, r2;
800
801  rx_ch_desc * rx_desc = &memmap->rx_descs[vc];
802
803  int was_idle = 0;
804
805  spin_lock_irqsave (&dev->mem_lock, flags);
806  value = rd_mem (dev, &rx_desc->wr_buf_type) & BUFFER_PTR_MASK;
807  spin_unlock_irqrestore (&dev->mem_lock, flags);
808
809  if (value == RX_CHANNEL_DISABLED) {
810    // I suppose this could happen once we deal with _NONE traffic properly
811    PRINTD (DBG_VCC, "closing VC: RX channel %u already disabled", vc);
812    return;
813  }
814  if (value == RX_CHANNEL_IDLE)
815    was_idle = 1;
816
817  spin_lock_irqsave (&dev->mem_lock, flags);
818
819  for (;;) {
820    wr_mem (dev, &rx_desc->wr_buf_type, RX_CHANNEL_DISABLED);
821
822    if ((rd_mem (dev, &rx_desc->wr_buf_type) & BUFFER_PTR_MASK) == RX_CHANNEL_DISABLED)
823      break;
824
825    was_idle = 0;
826  }
827
828  if (was_idle) {
829    spin_unlock_irqrestore (&dev->mem_lock, flags);
830    return;
831  }
832
833  WAIT_FLUSH_RX_COMPLETE(dev);
834
835  // XXX Is this all really necessary? We can rely on the rx_data_av
836  // handler to discard frames that remain queued for delivery. If the
837  // worry is that immediately reopening the channel (perhaps by a
838  // different process) may cause some data to be mis-delivered then
839  // there may still be a simpler solution (such as busy-waiting on
840  // rx_busy once the channel is disabled or before a new one is
841  // opened - does this leave any holes?). Arguably setting up and
842  // tearing down the TX and RX halves of each virtual circuit could
843  // most safely be done within ?x_busy protected regions.
844
845  // OK, current changes are that Simon's marker is disabled and we DO
846  // look for NULL rxer elsewhere. The code here seems flush frames
847  // and then remember the last dead cell belonging to the channel
848  // just disabled - the cell gets relinked at the next vc_open.
849  // However, when all VCs are closed or only a few opened there are a
850  // handful of buffers that are unusable.
851
852  // Does anyone feel like documenting spare_buffers properly?
853  // Does anyone feel like fixing this in a nicer way?
854
855  // Flush any data which is left in the channel
856  for (;;) {
857    // Change the rx channel port to something different to the RX
858    // channel we are trying to close to force Horizon to flush the rx
859    // channel read and write pointers.
860
861    u16 other = vc^(RX_CHANS/2);
862
863    SELECT_RX_CHANNEL (dev, other);
864    WAIT_UPDATE_COMPLETE (dev);
865
866    r1 = rd_mem (dev, &rx_desc->rd_buf_type);
867
868    // Select this RX channel. Flush doesn't seem to work unless we
869    // select an RX channel before hand
870
871    SELECT_RX_CHANNEL (dev, vc);
872    WAIT_UPDATE_COMPLETE (dev);
873
874    // Attempt to flush a frame on this RX channel
875
876    FLUSH_RX_CHANNEL (dev, vc);
877    WAIT_FLUSH_RX_COMPLETE (dev);
878
879    // Force Horizon to flush rx channel read and write pointers as before
880
881    SELECT_RX_CHANNEL (dev, other);
882    WAIT_UPDATE_COMPLETE (dev);
883
884    r2 = rd_mem (dev, &rx_desc->rd_buf_type);
885
886    PRINTD (DBG_VCC|DBG_RX, "r1 = %u, r2 = %u", r1, r2);
887
888    if (r1 == r2) {
889      dev->spare_buffers[dev->noof_spare_buffers++] = (u16)r1;
890      break;
891    }
892  }
893
894#if 0
895  {
896    rx_q_entry * wr_ptr = &memmap->rx_q_entries[rd_regw (dev, RX_QUEUE_WR_PTR_OFF)];
897    rx_q_entry * rd_ptr = dev->rx_q_entry;
898
899    PRINTD (DBG_VCC|DBG_RX, "rd_ptr = %u, wr_ptr = %u", rd_ptr, wr_ptr);
900
901    while (rd_ptr != wr_ptr) {
902      u32 x = rd_mem (dev, (HDW *) rd_ptr);
903
904      if (vc == rx_q_entry_to_rx_channel (x)) {
905	x |= SIMONS_DODGEY_MARKER;
906
907	PRINTD (DBG_RX|DBG_VCC|DBG_WARN, "marking a frame as dodgey");
908
909	wr_mem (dev, (HDW *) rd_ptr, x);
910      }
911
912      if (rd_ptr == dev->rx_q_wrap)
913	rd_ptr = dev->rx_q_reset;
914      else
915	rd_ptr++;
916    }
917  }
918#endif
919
920  spin_unlock_irqrestore (&dev->mem_lock, flags);
921
922  return;
923}
924
925/********** schedule RX transfers **********/
926
927// Note on tail recursion: a GCC developer said that it is not likely
928// to be fixed soon, so do not define TAILRECUSRIONWORKS unless you
929// are sure it does as you may otherwise overflow the kernel stack.
930
931// giving this fn a return value would help GCC, allegedly
932
933static void rx_schedule (hrz_dev * dev, int irq) {
934  unsigned int rx_bytes;
935
936  int pio_instead = 0;
937#ifndef TAILRECURSIONWORKS
938  pio_instead = 1;
939  while (pio_instead) {
940#endif
941    // bytes waiting for RX transfer
942    rx_bytes = dev->rx_bytes;
943
944#if 0
945    spin_count = 0;
946    while (rd_regl (dev, MASTER_RX_COUNT_REG_OFF)) {
947      PRINTD (DBG_RX|DBG_WARN, "RX error: other PCI Bus Master RX still in progress!");
948      if (++spin_count > 10) {
949	PRINTD (DBG_RX|DBG_ERR, "spun out waiting PCI Bus Master RX completion");
950	wr_regl (dev, MASTER_RX_COUNT_REG_OFF, 0);
951	clear_bit (rx_busy, &dev->flags);
952	hrz_kfree_skb (dev->rx_skb);
953	return;
954      }
955    }
956#endif
957
958    // this code follows the TX code but (at the moment) there is only
959    // one region - the skb itself. I don't know if this will change,
960    // but it doesn't hurt to have the code here, disabled.
961
962    if (rx_bytes) {
963      // start next transfer within same region
964      if (rx_bytes <= MAX_PIO_COUNT) {
965	PRINTD (DBG_RX|DBG_BUS, "(pio)");
966	pio_instead = 1;
967      }
968      if (rx_bytes <= MAX_TRANSFER_COUNT) {
969	PRINTD (DBG_RX|DBG_BUS, "(simple or last multi)");
970	dev->rx_bytes = 0;
971      } else {
972	PRINTD (DBG_RX|DBG_BUS, "(continuing multi)");
973	dev->rx_bytes = rx_bytes - MAX_TRANSFER_COUNT;
974	rx_bytes = MAX_TRANSFER_COUNT;
975      }
976    } else {
977      // rx_bytes == 0 -- we're between regions
978      // regions remaining to transfer
979#if 0
980      unsigned int rx_regions = dev->rx_regions;
981#else
982      unsigned int rx_regions = 0;
983#endif
984
985      if (rx_regions) {
986#if 0
987	// start a new region
988	dev->rx_addr = dev->rx_iovec->iov_base;
989	rx_bytes = dev->rx_iovec->iov_len;
990	++dev->rx_iovec;
991	dev->rx_regions = rx_regions - 1;
992
993	if (rx_bytes <= MAX_PIO_COUNT) {
994	  PRINTD (DBG_RX|DBG_BUS, "(pio)");
995	  pio_instead = 1;
996	}
997	if (rx_bytes <= MAX_TRANSFER_COUNT) {
998	  PRINTD (DBG_RX|DBG_BUS, "(full region)");
999	  dev->rx_bytes = 0;
1000	} else {
1001	  PRINTD (DBG_RX|DBG_BUS, "(start multi region)");
1002	  dev->rx_bytes = rx_bytes - MAX_TRANSFER_COUNT;
1003	  rx_bytes = MAX_TRANSFER_COUNT;
1004	}
1005#endif
1006      } else {
1007	// rx_regions == 0
1008	// that's all folks - end of frame
1009	struct sk_buff * skb = dev->rx_skb;
1010	// dev->rx_iovec = 0;
1011
1012	FLUSH_RX_CHANNEL (dev, dev->rx_channel);
1013
1014	dump_skb ("<<<", dev->rx_channel, skb);
1015
1016	PRINTD (DBG_RX|DBG_SKB, "push %p %u", skb->data, skb->len);
1017
1018	{
1019	  struct atm_vcc * vcc = ATM_SKB(skb)->vcc;
1020	  // VC layer stats
1021	  atomic_inc(&vcc->stats->rx);
1022	  __net_timestamp(skb);
1023	  // end of our responsibility
1024	  vcc->push (vcc, skb);
1025	}
1026      }
1027    }
1028
1029    // note: writing RX_COUNT clears any interrupt condition
1030    if (rx_bytes) {
1031      if (pio_instead) {
1032	if (irq)
1033	  wr_regl (dev, MASTER_RX_COUNT_REG_OFF, 0);
1034	rds_regb (dev, DATA_PORT_OFF, dev->rx_addr, rx_bytes);
1035      } else {
1036	wr_regl (dev, MASTER_RX_ADDR_REG_OFF, virt_to_bus (dev->rx_addr));
1037	wr_regl (dev, MASTER_RX_COUNT_REG_OFF, rx_bytes);
1038      }
1039      dev->rx_addr += rx_bytes;
1040    } else {
1041      if (irq)
1042	wr_regl (dev, MASTER_RX_COUNT_REG_OFF, 0);
1043      // allow another RX thread to start
1044      YELLOW_LED_ON(dev);
1045      clear_bit (rx_busy, &dev->flags);
1046      PRINTD (DBG_RX, "cleared rx_busy for dev %p", dev);
1047    }
1048
1049#ifdef TAILRECURSIONWORKS
1050    // and we all bless optimised tail calls
1051    if (pio_instead)
1052      return rx_schedule (dev, 0);
1053    return;
1054#else
1055    // grrrrrrr!
1056    irq = 0;
1057  }
1058  return;
1059#endif
1060}
1061
1062/********** handle RX bus master complete events **********/
1063
1064static void rx_bus_master_complete_handler (hrz_dev * dev) {
1065  if (test_bit (rx_busy, &dev->flags)) {
1066    rx_schedule (dev, 1);
1067  } else {
1068    PRINTD (DBG_RX|DBG_ERR, "unexpected RX bus master completion");
1069    // clear interrupt condition on adapter
1070    wr_regl (dev, MASTER_RX_COUNT_REG_OFF, 0);
1071  }
1072  return;
1073}
1074
1075/********** (queue to) become the next TX thread **********/
1076
1077static int tx_hold (hrz_dev * dev) {
1078  PRINTD (DBG_TX, "sleeping at tx lock %p %lu", dev, dev->flags);
1079  wait_event_interruptible(dev->tx_queue, (!test_and_set_bit(tx_busy, &dev->flags)));
1080  PRINTD (DBG_TX, "woken at tx lock %p %lu", dev, dev->flags);
1081  if (signal_pending (current))
1082    return -1;
1083  PRINTD (DBG_TX, "set tx_busy for dev %p", dev);
1084  return 0;
1085}
1086
1087/********** allow another TX thread to start **********/
1088
1089static inline void tx_release (hrz_dev * dev) {
1090  clear_bit (tx_busy, &dev->flags);
1091  PRINTD (DBG_TX, "cleared tx_busy for dev %p", dev);
1092  wake_up_interruptible (&dev->tx_queue);
1093}
1094
1095/********** schedule TX transfers **********/
1096
1097static void tx_schedule (hrz_dev * const dev, int irq) {
1098  unsigned int tx_bytes;
1099
1100  int append_desc = 0;
1101
1102  int pio_instead = 0;
1103#ifndef TAILRECURSIONWORKS
1104  pio_instead = 1;
1105  while (pio_instead) {
1106#endif
1107    // bytes in current region waiting for TX transfer
1108    tx_bytes = dev->tx_bytes;
1109
1110#if 0
1111    spin_count = 0;
1112    while (rd_regl (dev, MASTER_TX_COUNT_REG_OFF)) {
1113      PRINTD (DBG_TX|DBG_WARN, "TX error: other PCI Bus Master TX still in progress!");
1114      if (++spin_count > 10) {
1115	PRINTD (DBG_TX|DBG_ERR, "spun out waiting PCI Bus Master TX completion");
1116	wr_regl (dev, MASTER_TX_COUNT_REG_OFF, 0);
1117	tx_release (dev);
1118	hrz_kfree_skb (dev->tx_skb);
1119	return;
1120      }
1121    }
1122#endif
1123
1124    if (tx_bytes) {
1125      // start next transfer within same region
1126      if (!test_bit (ultra, &dev->flags) || tx_bytes <= MAX_PIO_COUNT) {
1127	PRINTD (DBG_TX|DBG_BUS, "(pio)");
1128	pio_instead = 1;
1129      }
1130      if (tx_bytes <= MAX_TRANSFER_COUNT) {
1131	PRINTD (DBG_TX|DBG_BUS, "(simple or last multi)");
1132	if (!dev->tx_iovec) {
1133	  // end of last region
1134	  append_desc = 1;
1135	}
1136	dev->tx_bytes = 0;
1137      } else {
1138	PRINTD (DBG_TX|DBG_BUS, "(continuing multi)");
1139	dev->tx_bytes = tx_bytes - MAX_TRANSFER_COUNT;
1140	tx_bytes = MAX_TRANSFER_COUNT;
1141      }
1142    } else {
1143      // tx_bytes == 0 -- we're between regions
1144      // regions remaining to transfer
1145      unsigned int tx_regions = dev->tx_regions;
1146
1147      if (tx_regions) {
1148	// start a new region
1149	dev->tx_addr = dev->tx_iovec->iov_base;
1150	tx_bytes = dev->tx_iovec->iov_len;
1151	++dev->tx_iovec;
1152	dev->tx_regions = tx_regions - 1;
1153
1154	if (!test_bit (ultra, &dev->flags) || tx_bytes <= MAX_PIO_COUNT) {
1155	  PRINTD (DBG_TX|DBG_BUS, "(pio)");
1156	  pio_instead = 1;
1157	}
1158	if (tx_bytes <= MAX_TRANSFER_COUNT) {
1159	  PRINTD (DBG_TX|DBG_BUS, "(full region)");
1160	  dev->tx_bytes = 0;
1161	} else {
1162	  PRINTD (DBG_TX|DBG_BUS, "(start multi region)");
1163	  dev->tx_bytes = tx_bytes - MAX_TRANSFER_COUNT;
1164	  tx_bytes = MAX_TRANSFER_COUNT;
1165	}
1166      } else {
1167	// tx_regions == 0
1168	// that's all folks - end of frame
1169	struct sk_buff * skb = dev->tx_skb;
1170	dev->tx_iovec = NULL;
1171
1172	// VC layer stats
1173	atomic_inc(&ATM_SKB(skb)->vcc->stats->tx);
1174
1175	// free the skb
1176	hrz_kfree_skb (skb);
1177      }
1178    }
1179
1180    // note: writing TX_COUNT clears any interrupt condition
1181    if (tx_bytes) {
1182      if (pio_instead) {
1183	if (irq)
1184	  wr_regl (dev, MASTER_TX_COUNT_REG_OFF, 0);
1185	wrs_regb (dev, DATA_PORT_OFF, dev->tx_addr, tx_bytes);
1186	if (append_desc)
1187	  wr_regl (dev, TX_DESCRIPTOR_PORT_OFF, cpu_to_be32 (dev->tx_skb->len));
1188      } else {
1189	wr_regl (dev, MASTER_TX_ADDR_REG_OFF, virt_to_bus (dev->tx_addr));
1190	if (append_desc)
1191	  wr_regl (dev, TX_DESCRIPTOR_REG_OFF, cpu_to_be32 (dev->tx_skb->len));
1192	wr_regl (dev, MASTER_TX_COUNT_REG_OFF,
1193		 append_desc
1194		 ? tx_bytes | MASTER_TX_AUTO_APPEND_DESC
1195		 : tx_bytes);
1196      }
1197      dev->tx_addr += tx_bytes;
1198    } else {
1199      if (irq)
1200	wr_regl (dev, MASTER_TX_COUNT_REG_OFF, 0);
1201      YELLOW_LED_ON(dev);
1202      tx_release (dev);
1203    }
1204
1205#ifdef TAILRECURSIONWORKS
1206    // and we all bless optimised tail calls
1207    if (pio_instead)
1208      return tx_schedule (dev, 0);
1209    return;
1210#else
1211    // grrrrrrr!
1212    irq = 0;
1213  }
1214  return;
1215#endif
1216}
1217
1218/********** handle TX bus master complete events **********/
1219
1220static void tx_bus_master_complete_handler (hrz_dev * dev) {
1221  if (test_bit (tx_busy, &dev->flags)) {
1222    tx_schedule (dev, 1);
1223  } else {
1224    PRINTD (DBG_TX|DBG_ERR, "unexpected TX bus master completion");
1225    // clear interrupt condition on adapter
1226    wr_regl (dev, MASTER_TX_COUNT_REG_OFF, 0);
1227  }
1228  return;
1229}
1230
1231/********** move RX Q pointer to next item in circular buffer **********/
1232
1233// called only from IRQ sub-handler
1234static u32 rx_queue_entry_next (hrz_dev * dev) {
1235  u32 rx_queue_entry;
1236  spin_lock (&dev->mem_lock);
1237  rx_queue_entry = rd_mem (dev, &dev->rx_q_entry->entry);
1238  if (dev->rx_q_entry == dev->rx_q_wrap)
1239    dev->rx_q_entry = dev->rx_q_reset;
1240  else
1241    dev->rx_q_entry++;
1242  wr_regw (dev, RX_QUEUE_RD_PTR_OFF, dev->rx_q_entry - dev->rx_q_reset);
1243  spin_unlock (&dev->mem_lock);
1244  return rx_queue_entry;
1245}
1246
1247/********** handle RX data received by device **********/
1248
1249// called from IRQ handler
1250static void rx_data_av_handler (hrz_dev * dev) {
1251  u32 rx_queue_entry;
1252  u32 rx_queue_entry_flags;
1253  u16 rx_len;
1254  u16 rx_channel;
1255
1256  PRINTD (DBG_FLOW, "hrz_data_av_handler");
1257
1258  // try to grab rx lock (not possible during RX bus mastering)
1259  if (test_and_set_bit (rx_busy, &dev->flags)) {
1260    PRINTD (DBG_RX, "locked out of rx lock");
1261    return;
1262  }
1263  PRINTD (DBG_RX, "set rx_busy for dev %p", dev);
1264  // lock is cleared if we fail now, o/w after bus master completion
1265
1266  YELLOW_LED_OFF(dev);
1267
1268  rx_queue_entry = rx_queue_entry_next (dev);
1269
1270  rx_len = rx_q_entry_to_length (rx_queue_entry);
1271  rx_channel = rx_q_entry_to_rx_channel (rx_queue_entry);
1272
1273  WAIT_FLUSH_RX_COMPLETE (dev);
1274
1275  SELECT_RX_CHANNEL (dev, rx_channel);
1276
1277  PRINTD (DBG_RX, "rx_queue_entry is: %#x", rx_queue_entry);
1278  rx_queue_entry_flags = rx_queue_entry & (RX_CRC_32_OK|RX_COMPLETE_FRAME|SIMONS_DODGEY_MARKER);
1279
1280  if (!rx_len) {
1281    // (at least) bus-mastering breaks if we try to handle a
1282    // zero-length frame, besides AAL5 does not support them
1283    PRINTK (KERN_ERR, "zero-length frame!");
1284    rx_queue_entry_flags &= ~RX_COMPLETE_FRAME;
1285  }
1286
1287  if (rx_queue_entry_flags & SIMONS_DODGEY_MARKER) {
1288    PRINTD (DBG_RX|DBG_ERR, "Simon's marker detected!");
1289  }
1290  if (rx_queue_entry_flags == (RX_CRC_32_OK | RX_COMPLETE_FRAME)) {
1291    struct atm_vcc * atm_vcc;
1292
1293    PRINTD (DBG_RX, "got a frame on rx_channel %x len %u", rx_channel, rx_len);
1294
1295    atm_vcc = dev->rxer[rx_channel];
1296    // if no vcc is assigned to this channel, we should drop the frame
1297    // (is this what SIMONS etc. was trying to achieve?)
1298
1299    if (atm_vcc) {
1300
1301      if (atm_vcc->qos.rxtp.traffic_class != ATM_NONE) {
1302
1303	if (rx_len <= atm_vcc->qos.rxtp.max_sdu) {
1304
1305	  struct sk_buff * skb = atm_alloc_charge (atm_vcc, rx_len, GFP_ATOMIC);
1306	  if (skb) {
1307	    // remember this so we can push it later
1308	    dev->rx_skb = skb;
1309	    // remember this so we can flush it later
1310	    dev->rx_channel = rx_channel;
1311
1312	    // prepare socket buffer
1313	    skb_put (skb, rx_len);
1314	    ATM_SKB(skb)->vcc = atm_vcc;
1315
1316	    // simple transfer
1317	    // dev->rx_regions = 0;
1318	    // dev->rx_iovec = 0;
1319	    dev->rx_bytes = rx_len;
1320	    dev->rx_addr = skb->data;
1321	    PRINTD (DBG_RX, "RX start simple transfer (addr %p, len %d)",
1322		    skb->data, rx_len);
1323
1324	    // do the business
1325	    rx_schedule (dev, 0);
1326	    return;
1327
1328	  } else {
1329	    PRINTD (DBG_SKB|DBG_WARN, "failed to get skb");
1330	  }
1331
1332	} else {
1333	  PRINTK (KERN_INFO, "frame received on TX-only VC %x", rx_channel);
1334	  // do we count this?
1335	}
1336
1337      } else {
1338	PRINTK (KERN_WARNING, "dropped over-size frame");
1339	// do we count this?
1340      }
1341
1342    } else {
1343      PRINTD (DBG_WARN|DBG_VCC|DBG_RX, "no VCC for this frame (VC closed)");
1344      // do we count this?
1345    }
1346
1347  } else {
1348    // Wait update complete ? SPONG
1349  }
1350
1351  // RX was aborted
1352  YELLOW_LED_ON(dev);
1353
1354  FLUSH_RX_CHANNEL (dev,rx_channel);
1355  clear_bit (rx_busy, &dev->flags);
1356
1357  return;
1358}
1359
1360/********** interrupt handler **********/
1361
1362static irqreturn_t interrupt_handler(int irq, void *dev_id)
1363{
1364  hrz_dev *dev = dev_id;
1365  u32 int_source;
1366  unsigned int irq_ok;
1367
1368  PRINTD (DBG_FLOW, "interrupt_handler: %p", dev_id);
1369
1370  // definitely for us
1371  irq_ok = 0;
1372  while ((int_source = rd_regl (dev, INT_SOURCE_REG_OFF)
1373	  & INTERESTING_INTERRUPTS)) {
1374    // In the interests of fairness, the handlers below are
1375    // called in sequence and without immediate return to the head of
1376    // the while loop. This is only of issue for slow hosts (or when
1377    // debugging messages are on). Really slow hosts may find a fast
1378    // sender keeps them permanently in the IRQ handler. :(
1379
1380    // (only an issue for slow hosts) RX completion goes before
1381    // rx_data_av as the former implies rx_busy and so the latter
1382    // would just abort. If it reschedules another transfer
1383    // (continuing the same frame) then it will not clear rx_busy.
1384
1385    // (only an issue for slow hosts) TX completion goes before RX
1386    // data available as it is a much shorter routine - there is the
1387    // chance that any further transfers it schedules will be complete
1388    // by the time of the return to the head of the while loop
1389
1390    if (int_source & RX_BUS_MASTER_COMPLETE) {
1391      ++irq_ok;
1392      PRINTD (DBG_IRQ|DBG_BUS|DBG_RX, "rx_bus_master_complete asserted");
1393      rx_bus_master_complete_handler (dev);
1394    }
1395    if (int_source & TX_BUS_MASTER_COMPLETE) {
1396      ++irq_ok;
1397      PRINTD (DBG_IRQ|DBG_BUS|DBG_TX, "tx_bus_master_complete asserted");
1398      tx_bus_master_complete_handler (dev);
1399    }
1400    if (int_source & RX_DATA_AV) {
1401      ++irq_ok;
1402      PRINTD (DBG_IRQ|DBG_RX, "rx_data_av asserted");
1403      rx_data_av_handler (dev);
1404    }
1405  }
1406  if (irq_ok) {
1407    PRINTD (DBG_IRQ, "work done: %u", irq_ok);
1408  } else {
1409    PRINTD (DBG_IRQ|DBG_WARN, "spurious interrupt source: %#x", int_source);
1410  }
1411
1412  PRINTD (DBG_IRQ|DBG_FLOW, "interrupt_handler done: %p", dev_id);
1413  if (irq_ok)
1414	return IRQ_HANDLED;
1415  return IRQ_NONE;
1416}
1417
1418/********** housekeeping **********/
1419
1420static void do_housekeeping (unsigned long arg) {
1421  // just stats at the moment
1422  hrz_dev * dev = (hrz_dev *) arg;
1423
1424  // collect device-specific (not driver/atm-linux) stats here
1425  dev->tx_cell_count += rd_regw (dev, TX_CELL_COUNT_OFF);
1426  dev->rx_cell_count += rd_regw (dev, RX_CELL_COUNT_OFF);
1427  dev->hec_error_count += rd_regw (dev, HEC_ERROR_COUNT_OFF);
1428  dev->unassigned_cell_count += rd_regw (dev, UNASSIGNED_CELL_COUNT_OFF);
1429
1430  mod_timer (&dev->housekeeping, jiffies + HZ/10);
1431
1432  return;
1433}
1434
1435/********** find an idle channel for TX and set it up **********/
1436
1437// called with tx_busy set
1438static short setup_idle_tx_channel (hrz_dev * dev, hrz_vcc * vcc) {
1439  unsigned short idle_channels;
1440  short tx_channel = -1;
1441  unsigned int spin_count;
1442  PRINTD (DBG_FLOW|DBG_TX, "setup_idle_tx_channel %p", dev);
1443
1444  // better would be to fail immediately, the caller can then decide whether
1445  // to wait or drop (depending on whether this is UBR etc.)
1446  spin_count = 0;
1447  while (!(idle_channels = rd_regw (dev, TX_STATUS_OFF) & IDLE_CHANNELS_MASK)) {
1448    PRINTD (DBG_TX|DBG_WARN, "waiting for idle TX channel");
1449    // delay a bit here
1450    if (++spin_count > 100) {
1451      PRINTD (DBG_TX|DBG_ERR, "spun out waiting for idle TX channel");
1452      return -EBUSY;
1453    }
1454  }
1455
1456  // got an idle channel
1457  {
1458    // tx_idle ensures we look for idle channels in RR order
1459    int chan = dev->tx_idle;
1460
1461    int keep_going = 1;
1462    while (keep_going) {
1463      if (idle_channels & (1<<chan)) {
1464	tx_channel = chan;
1465	keep_going = 0;
1466      }
1467      ++chan;
1468      if (chan == TX_CHANS)
1469	chan = 0;
1470    }
1471
1472    dev->tx_idle = chan;
1473  }
1474
1475  // set up the channel we found
1476  {
1477    // Initialise the cell header in the transmit channel descriptor
1478    // a.k.a. prepare the channel and remember that we have done so.
1479
1480    tx_ch_desc * tx_desc = &memmap->tx_descs[tx_channel];
1481    u32 rd_ptr;
1482    u32 wr_ptr;
1483    u16 channel = vcc->channel;
1484
1485    unsigned long flags;
1486    spin_lock_irqsave (&dev->mem_lock, flags);
1487
1488    // Update the transmit channel record.
1489    dev->tx_channel_record[tx_channel] = channel;
1490
1491    // xBR channel
1492    update_tx_channel_config (dev, tx_channel, RATE_TYPE_ACCESS,
1493			      vcc->tx_xbr_bits);
1494
1495    // Update the PCR counter preload value etc.
1496    update_tx_channel_config (dev, tx_channel, PCR_TIMER_ACCESS,
1497			      vcc->tx_pcr_bits);
1498
1499#if 0
1500    if (vcc->tx_xbr_bits == VBR_RATE_TYPE) {
1501      // SCR timer
1502      update_tx_channel_config (dev, tx_channel, SCR_TIMER_ACCESS,
1503				vcc->tx_scr_bits);
1504
1505      // Bucket size...
1506      update_tx_channel_config (dev, tx_channel, BUCKET_CAPACITY_ACCESS,
1507				vcc->tx_bucket_bits);
1508
1509      // ... and fullness
1510      update_tx_channel_config (dev, tx_channel, BUCKET_FULLNESS_ACCESS,
1511				vcc->tx_bucket_bits);
1512    }
1513#endif
1514
1515    // Initialise the read and write buffer pointers
1516    rd_ptr = rd_mem (dev, &tx_desc->rd_buf_type) & BUFFER_PTR_MASK;
1517    wr_ptr = rd_mem (dev, &tx_desc->wr_buf_type) & BUFFER_PTR_MASK;
1518
1519    // idle TX channels should have identical pointers
1520    if (rd_ptr != wr_ptr) {
1521      PRINTD (DBG_TX|DBG_ERR, "TX buffer pointers are broken!");
1522      // spin_unlock... return -E...
1523      // I wonder if gcc would get rid of one of the pointer aliases
1524    }
1525    PRINTD (DBG_TX, "TX buffer pointers are: rd %x, wr %x.",
1526	    rd_ptr, wr_ptr);
1527
1528    switch (vcc->aal) {
1529      case aal0:
1530	PRINTD (DBG_QOS|DBG_TX, "tx_channel: aal0");
1531	rd_ptr |= CHANNEL_TYPE_RAW_CELLS;
1532	wr_ptr |= CHANNEL_TYPE_RAW_CELLS;
1533	break;
1534      case aal34:
1535	PRINTD (DBG_QOS|DBG_TX, "tx_channel: aal34");
1536	rd_ptr |= CHANNEL_TYPE_AAL3_4;
1537	wr_ptr |= CHANNEL_TYPE_AAL3_4;
1538	break;
1539      case aal5:
1540	rd_ptr |= CHANNEL_TYPE_AAL5;
1541	wr_ptr |= CHANNEL_TYPE_AAL5;
1542	// Initialise the CRC
1543	wr_mem (dev, &tx_desc->partial_crc, INITIAL_CRC);
1544	break;
1545    }
1546
1547    wr_mem (dev, &tx_desc->rd_buf_type, rd_ptr);
1548    wr_mem (dev, &tx_desc->wr_buf_type, wr_ptr);
1549
1550    // Write the Cell Header
1551    // Payload Type, CLP and GFC would go here if non-zero
1552    wr_mem (dev, &tx_desc->cell_header, channel);
1553
1554    spin_unlock_irqrestore (&dev->mem_lock, flags);
1555  }
1556
1557  return tx_channel;
1558}
1559
1560/********** send a frame **********/
1561
1562static int hrz_send (struct atm_vcc * atm_vcc, struct sk_buff * skb) {
1563  unsigned int spin_count;
1564  int free_buffers;
1565  hrz_dev * dev = HRZ_DEV(atm_vcc->dev);
1566  hrz_vcc * vcc = HRZ_VCC(atm_vcc);
1567  u16 channel = vcc->channel;
1568
1569  u32 buffers_required;
1570
1571  /* signed for error return */
1572  short tx_channel;
1573
1574  PRINTD (DBG_FLOW|DBG_TX, "hrz_send vc %x data %p len %u",
1575	  channel, skb->data, skb->len);
1576
1577  dump_skb (">>>", channel, skb);
1578
1579  if (atm_vcc->qos.txtp.traffic_class == ATM_NONE) {
1580    PRINTK (KERN_ERR, "attempt to send on RX-only VC %x", channel);
1581    hrz_kfree_skb (skb);
1582    return -EIO;
1583  }
1584
1585  // don't understand this
1586  ATM_SKB(skb)->vcc = atm_vcc;
1587
1588  if (skb->len > atm_vcc->qos.txtp.max_sdu) {
1589    PRINTK (KERN_ERR, "sk_buff length greater than agreed max_sdu, dropping...");
1590    hrz_kfree_skb (skb);
1591    return -EIO;
1592  }
1593
1594  if (!channel) {
1595    PRINTD (DBG_ERR|DBG_TX, "attempt to transmit on zero (rx_)channel");
1596    hrz_kfree_skb (skb);
1597    return -EIO;
1598  }
1599
1600#if 0
1601  {
1602    // where would be a better place for this? housekeeping?
1603    u16 status;
1604    pci_read_config_word (dev->pci_dev, PCI_STATUS, &status);
1605    if (status & PCI_STATUS_REC_MASTER_ABORT) {
1606      PRINTD (DBG_BUS|DBG_ERR, "Clearing PCI Master Abort (and cleaning up)");
1607      status &= ~PCI_STATUS_REC_MASTER_ABORT;
1608      pci_write_config_word (dev->pci_dev, PCI_STATUS, status);
1609      if (test_bit (tx_busy, &dev->flags)) {
1610	hrz_kfree_skb (dev->tx_skb);
1611	tx_release (dev);
1612      }
1613    }
1614  }
1615#endif
1616
1617#ifdef DEBUG_HORIZON
1618  /* wey-hey! */
1619  if (channel == 1023) {
1620    unsigned int i;
1621    unsigned short d = 0;
1622    char * s = skb->data;
1623    if (*s++ == 'D') {
1624	for (i = 0; i < 4; ++i)
1625		d = (d << 4) | hex_to_bin(*s++);
1626      PRINTK (KERN_INFO, "debug bitmap is now %hx", debug = d);
1627    }
1628  }
1629#endif
1630
1631  // wait until TX is free and grab lock
1632  if (tx_hold (dev)) {
1633    hrz_kfree_skb (skb);
1634    return -ERESTARTSYS;
1635  }
1636
1637  // Wait for enough space to be available in transmit buffer memory.
1638
1639  // should be number of cells needed + 2 (according to hardware docs)
1640  // = ((framelen+8)+47) / 48 + 2
1641  // = (framelen+7) / 48 + 3, hmm... faster to put addition inside XXX
1642  buffers_required = (skb->len+(ATM_AAL5_TRAILER-1)) / ATM_CELL_PAYLOAD + 3;
1643
1644  // replace with timer and sleep, add dev->tx_buffers_queue (max 1 entry)
1645  spin_count = 0;
1646  while ((free_buffers = rd_regw (dev, TX_FREE_BUFFER_COUNT_OFF)) < buffers_required) {
1647    PRINTD (DBG_TX, "waiting for free TX buffers, got %d of %d",
1648	    free_buffers, buffers_required);
1649    // what is the appropriate delay? implement a timeout? (depending on line speed?)
1650    // mdelay (1);
1651    // what happens if we kill (current_pid, SIGKILL) ?
1652    schedule();
1653    if (++spin_count > 1000) {
1654      PRINTD (DBG_TX|DBG_ERR, "spun out waiting for tx buffers, got %d of %d",
1655	      free_buffers, buffers_required);
1656      tx_release (dev);
1657      hrz_kfree_skb (skb);
1658      return -ERESTARTSYS;
1659    }
1660  }
1661
1662  // Select a channel to transmit the frame on.
1663  if (channel == dev->last_vc) {
1664    PRINTD (DBG_TX, "last vc hack: hit");
1665    tx_channel = dev->tx_last;
1666  } else {
1667    PRINTD (DBG_TX, "last vc hack: miss");
1668    // Are we currently transmitting this VC on one of the channels?
1669    for (tx_channel = 0; tx_channel < TX_CHANS; ++tx_channel)
1670      if (dev->tx_channel_record[tx_channel] == channel) {
1671	PRINTD (DBG_TX, "vc already on channel: hit");
1672	break;
1673      }
1674    if (tx_channel == TX_CHANS) {
1675      PRINTD (DBG_TX, "vc already on channel: miss");
1676      // Find and set up an idle channel.
1677      tx_channel = setup_idle_tx_channel (dev, vcc);
1678      if (tx_channel < 0) {
1679	PRINTD (DBG_TX|DBG_ERR, "failed to get channel");
1680	tx_release (dev);
1681	return tx_channel;
1682      }
1683    }
1684
1685    PRINTD (DBG_TX, "got channel");
1686    SELECT_TX_CHANNEL(dev, tx_channel);
1687
1688    dev->last_vc = channel;
1689    dev->tx_last = tx_channel;
1690  }
1691
1692  PRINTD (DBG_TX, "using channel %u", tx_channel);
1693
1694  YELLOW_LED_OFF(dev);
1695
1696  // TX start transfer
1697
1698  {
1699    unsigned int tx_len = skb->len;
1700    unsigned int tx_iovcnt = skb_shinfo(skb)->nr_frags;
1701    // remember this so we can free it later
1702    dev->tx_skb = skb;
1703
1704    if (tx_iovcnt) {
1705      // scatter gather transfer
1706      dev->tx_regions = tx_iovcnt;
1707      dev->tx_iovec = NULL;		/* @@@ needs rewritten */
1708      dev->tx_bytes = 0;
1709      PRINTD (DBG_TX|DBG_BUS, "TX start scatter-gather transfer (iovec %p, len %d)",
1710	      skb->data, tx_len);
1711      tx_release (dev);
1712      hrz_kfree_skb (skb);
1713      return -EIO;
1714    } else {
1715      // simple transfer
1716      dev->tx_regions = 0;
1717      dev->tx_iovec = NULL;
1718      dev->tx_bytes = tx_len;
1719      dev->tx_addr = skb->data;
1720      PRINTD (DBG_TX|DBG_BUS, "TX start simple transfer (addr %p, len %d)",
1721	      skb->data, tx_len);
1722    }
1723
1724    // and do the business
1725    tx_schedule (dev, 0);
1726
1727  }
1728
1729  return 0;
1730}
1731
1732/********** reset a card **********/
1733
1734static void hrz_reset (const hrz_dev * dev) {
1735  u32 control_0_reg = rd_regl (dev, CONTROL_0_REG);
1736
1737  // why not set RESET_HORIZON to one and wait for the card to
1738  // reassert that bit as zero? Like so:
1739  control_0_reg = control_0_reg & RESET_HORIZON;
1740  wr_regl (dev, CONTROL_0_REG, control_0_reg);
1741  while (control_0_reg & RESET_HORIZON)
1742    control_0_reg = rd_regl (dev, CONTROL_0_REG);
1743
1744  // old reset code retained:
1745  wr_regl (dev, CONTROL_0_REG, control_0_reg |
1746	   RESET_ATM | RESET_RX | RESET_TX | RESET_HOST);
1747  // just guessing here
1748  udelay (1000);
1749
1750  wr_regl (dev, CONTROL_0_REG, control_0_reg);
1751}
1752
1753/********** read the burnt in address **********/
1754
1755static void WRITE_IT_WAIT (const hrz_dev *dev, u32 ctrl)
1756{
1757	wr_regl (dev, CONTROL_0_REG, ctrl);
1758	udelay (5);
1759}
1760
1761static void CLOCK_IT (const hrz_dev *dev, u32 ctrl)
1762{
1763	// DI must be valid around rising SK edge
1764	WRITE_IT_WAIT(dev, ctrl & ~SEEPROM_SK);
1765	WRITE_IT_WAIT(dev, ctrl | SEEPROM_SK);
1766}
1767
1768static u16 read_bia(const hrz_dev *dev, u16 addr)
1769{
1770  u32 ctrl = rd_regl (dev, CONTROL_0_REG);
1771
1772  const unsigned int addr_bits = 6;
1773  const unsigned int data_bits = 16;
1774
1775  unsigned int i;
1776
1777  u16 res;
1778
1779  ctrl &= ~(SEEPROM_CS | SEEPROM_SK | SEEPROM_DI);
1780  WRITE_IT_WAIT(dev, ctrl);
1781
1782  // wake Serial EEPROM and send 110 (READ) command
1783  ctrl |=  (SEEPROM_CS | SEEPROM_DI);
1784  CLOCK_IT(dev, ctrl);
1785
1786  ctrl |= SEEPROM_DI;
1787  CLOCK_IT(dev, ctrl);
1788
1789  ctrl &= ~SEEPROM_DI;
1790  CLOCK_IT(dev, ctrl);
1791
1792  for (i=0; i<addr_bits; i++) {
1793    if (addr & (1 << (addr_bits-1)))
1794      ctrl |= SEEPROM_DI;
1795    else
1796      ctrl &= ~SEEPROM_DI;
1797
1798    CLOCK_IT(dev, ctrl);
1799
1800    addr = addr << 1;
1801  }
1802
1803  // we could check that we have DO = 0 here
1804  ctrl &= ~SEEPROM_DI;
1805
1806  res = 0;
1807  for (i=0;i<data_bits;i++) {
1808    res = res >> 1;
1809
1810    CLOCK_IT(dev, ctrl);
1811
1812    if (rd_regl (dev, CONTROL_0_REG) & SEEPROM_DO)
1813      res |= (1 << (data_bits-1));
1814  }
1815
1816  ctrl &= ~(SEEPROM_SK | SEEPROM_CS);
1817  WRITE_IT_WAIT(dev, ctrl);
1818
1819  return res;
1820}
1821
1822/********** initialise a card **********/
1823
1824static int hrz_init(hrz_dev *dev)
1825{
1826  int onefivefive;
1827
1828  u16 chan;
1829
1830  int buff_count;
1831
1832  HDW * mem;
1833
1834  cell_buf * tx_desc;
1835  cell_buf * rx_desc;
1836
1837  u32 ctrl;
1838
1839  ctrl = rd_regl (dev, CONTROL_0_REG);
1840  PRINTD (DBG_INFO, "ctrl0reg is %#x", ctrl);
1841  onefivefive = ctrl & ATM_LAYER_STATUS;
1842
1843  if (onefivefive)
1844    printk (DEV_LABEL ": Horizon Ultra (at 155.52 MBps)");
1845  else
1846    printk (DEV_LABEL ": Horizon (at 25 MBps)");
1847
1848  printk (":");
1849  // Reset the card to get everything in a known state
1850
1851  printk (" reset");
1852  hrz_reset (dev);
1853
1854  // Clear all the buffer memory
1855
1856  printk (" clearing memory");
1857
1858  for (mem = (HDW *) memmap; mem < (HDW *) (memmap + 1); ++mem)
1859    wr_mem (dev, mem, 0);
1860
1861  printk (" tx channels");
1862
1863  // All transmit eight channels are set up as AAL5 ABR channels with
1864  // a 16us cell spacing. Why?
1865
1866  // Channel 0 gets the free buffer at 100h, channel 1 gets the free
1867  // buffer at 110h etc.
1868
1869  for (chan = 0; chan < TX_CHANS; ++chan) {
1870    tx_ch_desc * tx_desc = &memmap->tx_descs[chan];
1871    cell_buf * buf = &memmap->inittxbufs[chan];
1872
1873    // initialise the read and write buffer pointers
1874    wr_mem (dev, &tx_desc->rd_buf_type, BUF_PTR(buf));
1875    wr_mem (dev, &tx_desc->wr_buf_type, BUF_PTR(buf));
1876
1877    // set the status of the initial buffers to empty
1878    wr_mem (dev, &buf->next, BUFF_STATUS_EMPTY);
1879  }
1880
1881  // Use space bufn3 at the moment for tx buffers
1882
1883  printk (" tx buffers");
1884
1885  tx_desc = memmap->bufn3;
1886
1887  wr_mem (dev, &memmap->txfreebufstart.next, BUF_PTR(tx_desc) | BUFF_STATUS_EMPTY);
1888
1889  for (buff_count = 0; buff_count < BUFN3_SIZE-1; buff_count++) {
1890    wr_mem (dev, &tx_desc->next, BUF_PTR(tx_desc+1) | BUFF_STATUS_EMPTY);
1891    tx_desc++;
1892  }
1893
1894  wr_mem (dev, &tx_desc->next, BUF_PTR(&memmap->txfreebufend) | BUFF_STATUS_EMPTY);
1895
1896  // Initialise the transmit free buffer count
1897  wr_regw (dev, TX_FREE_BUFFER_COUNT_OFF, BUFN3_SIZE);
1898
1899  printk (" rx channels");
1900
1901  // Initialise all of the receive channels to be AAL5 disabled with
1902  // an interrupt threshold of 0
1903
1904  for (chan = 0; chan < RX_CHANS; ++chan) {
1905    rx_ch_desc * rx_desc = &memmap->rx_descs[chan];
1906
1907    wr_mem (dev, &rx_desc->wr_buf_type, CHANNEL_TYPE_AAL5 | RX_CHANNEL_DISABLED);
1908  }
1909
1910  printk (" rx buffers");
1911
1912  // Use space bufn4 at the moment for rx buffers
1913
1914  rx_desc = memmap->bufn4;
1915
1916  wr_mem (dev, &memmap->rxfreebufstart.next, BUF_PTR(rx_desc) | BUFF_STATUS_EMPTY);
1917
1918  for (buff_count = 0; buff_count < BUFN4_SIZE-1; buff_count++) {
1919    wr_mem (dev, &rx_desc->next, BUF_PTR(rx_desc+1) | BUFF_STATUS_EMPTY);
1920
1921    rx_desc++;
1922  }
1923
1924  wr_mem (dev, &rx_desc->next, BUF_PTR(&memmap->rxfreebufend) | BUFF_STATUS_EMPTY);
1925
1926  // Initialise the receive free buffer count
1927  wr_regw (dev, RX_FREE_BUFFER_COUNT_OFF, BUFN4_SIZE);
1928
1929  // Initialize Horizons registers
1930
1931  // TX config
1932  wr_regw (dev, TX_CONFIG_OFF,
1933	   ABR_ROUND_ROBIN | TX_NORMAL_OPERATION | DRVR_DRVRBAR_ENABLE);
1934
1935  // RX config. Use 10-x VC bits, x VP bits, non user cells in channel 0.
1936  wr_regw (dev, RX_CONFIG_OFF,
1937	   DISCARD_UNUSED_VPI_VCI_BITS_SET | NON_USER_CELLS_IN_ONE_CHANNEL | vpi_bits);
1938
1939  // RX line config
1940  wr_regw (dev, RX_LINE_CONFIG_OFF,
1941	   LOCK_DETECT_ENABLE | FREQUENCY_DETECT_ENABLE | GXTALOUT_SELECT_DIV4);
1942
1943  // Set the max AAL5 cell count to be just enough to contain the
1944  // largest AAL5 frame that the user wants to receive
1945  wr_regw (dev, MAX_AAL5_CELL_COUNT_OFF,
1946	   DIV_ROUND_UP(max_rx_size + ATM_AAL5_TRAILER, ATM_CELL_PAYLOAD));
1947
1948  // Enable receive
1949  wr_regw (dev, RX_CONFIG_OFF, rd_regw (dev, RX_CONFIG_OFF) | RX_ENABLE);
1950
1951  printk (" control");
1952
1953  // Drive the OE of the LEDs then turn the green LED on
1954  ctrl |= GREEN_LED_OE | YELLOW_LED_OE | GREEN_LED | YELLOW_LED;
1955  wr_regl (dev, CONTROL_0_REG, ctrl);
1956
1957  // Test for a 155-capable card
1958
1959  if (onefivefive) {
1960    // Select 155 mode... make this a choice (or: how do we detect
1961    // external line speed and switch?)
1962    ctrl |= ATM_LAYER_SELECT;
1963    wr_regl (dev, CONTROL_0_REG, ctrl);
1964
1965    // test SUNI-lite vs SAMBA
1966
1967    // Register 0x00 in the SUNI will have some of bits 3-7 set, and
1968    // they will always be zero for the SAMBA.  Ha!  Bloody hardware
1969    // engineers.  It'll never work.
1970
1971    if (rd_framer (dev, 0) & 0x00f0) {
1972      // SUNI
1973      printk (" SUNI");
1974
1975      // Reset, just in case
1976      wr_framer (dev, 0x00, 0x0080);
1977      wr_framer (dev, 0x00, 0x0000);
1978
1979      // Configure transmit FIFO
1980      wr_framer (dev, 0x63, rd_framer (dev, 0x63) | 0x0002);
1981
1982      // Set line timed mode
1983      wr_framer (dev, 0x05, rd_framer (dev, 0x05) | 0x0001);
1984    } else {
1985      // SAMBA
1986      printk (" SAMBA");
1987
1988      // Reset, just in case
1989      wr_framer (dev, 0, rd_framer (dev, 0) | 0x0001);
1990      wr_framer (dev, 0, rd_framer (dev, 0) &~ 0x0001);
1991
1992      // Turn off diagnostic loopback and enable line-timed mode
1993      wr_framer (dev, 0, 0x0002);
1994
1995      // Turn on transmit outputs
1996      wr_framer (dev, 2, 0x0B80);
1997    }
1998  } else {
1999    // Select 25 mode
2000    ctrl &= ~ATM_LAYER_SELECT;
2001
2002    // Madge B154 setup
2003    // none required?
2004  }
2005
2006  printk (" LEDs");
2007
2008  GREEN_LED_ON(dev);
2009  YELLOW_LED_ON(dev);
2010
2011  printk (" ESI=");
2012
2013  {
2014    u16 b = 0;
2015    int i;
2016    u8 * esi = dev->atm_dev->esi;
2017
2018    // in the card I have, EEPROM
2019    // addresses 0, 1, 2 contain 0
2020    // addresess 5, 6 etc. contain ffff
2021    // NB: Madge prefix is 00 00 f6 (which is 00 00 6f in Ethernet bit order)
2022    // the read_bia routine gets the BIA in Ethernet bit order
2023
2024    for (i=0; i < ESI_LEN; ++i) {
2025      if (i % 2 == 0)
2026	b = read_bia (dev, i/2 + 2);
2027      else
2028	b = b >> 8;
2029      esi[i] = b & 0xFF;
2030      printk ("%02x", esi[i]);
2031    }
2032  }
2033
2034  // Enable RX_Q and ?X_COMPLETE interrupts only
2035  wr_regl (dev, INT_ENABLE_REG_OFF, INTERESTING_INTERRUPTS);
2036  printk (" IRQ on");
2037
2038  printk (".\n");
2039
2040  return onefivefive;
2041}
2042
2043/********** check max_sdu **********/
2044
2045static int check_max_sdu (hrz_aal aal, struct atm_trafprm * tp, unsigned int max_frame_size) {
2046  PRINTD (DBG_FLOW|DBG_QOS, "check_max_sdu");
2047
2048  switch (aal) {
2049    case aal0:
2050      if (!(tp->max_sdu)) {
2051	PRINTD (DBG_QOS, "defaulting max_sdu");
2052	tp->max_sdu = ATM_AAL0_SDU;
2053      } else if (tp->max_sdu != ATM_AAL0_SDU) {
2054	PRINTD (DBG_QOS|DBG_ERR, "rejecting max_sdu");
2055	return -EINVAL;
2056      }
2057      break;
2058    case aal34:
2059      if (tp->max_sdu == 0 || tp->max_sdu > ATM_MAX_AAL34_PDU) {
2060	PRINTD (DBG_QOS, "%sing max_sdu", tp->max_sdu ? "capp" : "default");
2061	tp->max_sdu = ATM_MAX_AAL34_PDU;
2062      }
2063      break;
2064    case aal5:
2065      if (tp->max_sdu == 0 || tp->max_sdu > max_frame_size) {
2066	PRINTD (DBG_QOS, "%sing max_sdu", tp->max_sdu ? "capp" : "default");
2067	tp->max_sdu = max_frame_size;
2068      }
2069      break;
2070  }
2071  return 0;
2072}
2073
2074/********** check pcr **********/
2075
2076// something like this should be part of ATM Linux
2077static int atm_pcr_check (struct atm_trafprm * tp, unsigned int pcr) {
2078  // we are assuming non-UBR, and non-special values of pcr
2079  if (tp->min_pcr == ATM_MAX_PCR)
2080    PRINTD (DBG_QOS, "luser gave min_pcr = ATM_MAX_PCR");
2081  else if (tp->min_pcr < 0)
2082    PRINTD (DBG_QOS, "luser gave negative min_pcr");
2083  else if (tp->min_pcr && tp->min_pcr > pcr)
2084    PRINTD (DBG_QOS, "pcr less than min_pcr");
2085  else
2086    // !! max_pcr = UNSPEC (0) is equivalent to max_pcr = MAX (-1)
2087    // easier to #define ATM_MAX_PCR 0 and have all rates unsigned?
2088    // [this would get rid of next two conditionals]
2089    if ((0) && tp->max_pcr == ATM_MAX_PCR)
2090      PRINTD (DBG_QOS, "luser gave max_pcr = ATM_MAX_PCR");
2091    else if ((tp->max_pcr != ATM_MAX_PCR) && tp->max_pcr < 0)
2092      PRINTD (DBG_QOS, "luser gave negative max_pcr");
2093    else if (tp->max_pcr && tp->max_pcr != ATM_MAX_PCR && tp->max_pcr < pcr)
2094      PRINTD (DBG_QOS, "pcr greater than max_pcr");
2095    else {
2096      // each limit unspecified or not violated
2097      PRINTD (DBG_QOS, "xBR(pcr) OK");
2098      return 0;
2099    }
2100  PRINTD (DBG_QOS, "pcr=%u, tp: min_pcr=%d, pcr=%d, max_pcr=%d",
2101	  pcr, tp->min_pcr, tp->pcr, tp->max_pcr);
2102  return -EINVAL;
2103}
2104
2105/********** open VC **********/
2106
2107static int hrz_open (struct atm_vcc *atm_vcc)
2108{
2109  int error;
2110  u16 channel;
2111
2112  struct atm_qos * qos;
2113  struct atm_trafprm * txtp;
2114  struct atm_trafprm * rxtp;
2115
2116  hrz_dev * dev = HRZ_DEV(atm_vcc->dev);
2117  hrz_vcc vcc;
2118  hrz_vcc * vccp; // allocated late
2119  short vpi = atm_vcc->vpi;
2120  int vci = atm_vcc->vci;
2121  PRINTD (DBG_FLOW|DBG_VCC, "hrz_open %x %x", vpi, vci);
2122
2123#ifdef ATM_VPI_UNSPEC
2124  // UNSPEC is deprecated, remove this code eventually
2125  if (vpi == ATM_VPI_UNSPEC || vci == ATM_VCI_UNSPEC) {
2126    PRINTK (KERN_WARNING, "rejecting open with unspecified VPI/VCI (deprecated)");
2127    return -EINVAL;
2128  }
2129#endif
2130
2131  error = vpivci_to_channel (&channel, vpi, vci);
2132  if (error) {
2133    PRINTD (DBG_WARN|DBG_VCC, "VPI/VCI out of range: %hd/%d", vpi, vci);
2134    return error;
2135  }
2136
2137  vcc.channel = channel;
2138  // max speed for the moment
2139  vcc.tx_rate = 0x0;
2140
2141  qos = &atm_vcc->qos;
2142
2143  // check AAL and remember it
2144  switch (qos->aal) {
2145    case ATM_AAL0:
2146      // we would if it were 48 bytes and not 52!
2147      PRINTD (DBG_QOS|DBG_VCC, "AAL0");
2148      vcc.aal = aal0;
2149      break;
2150    case ATM_AAL34:
2151      // we would if I knew how do the SAR!
2152      PRINTD (DBG_QOS|DBG_VCC, "AAL3/4");
2153      vcc.aal = aal34;
2154      break;
2155    case ATM_AAL5:
2156      PRINTD (DBG_QOS|DBG_VCC, "AAL5");
2157      vcc.aal = aal5;
2158      break;
2159    default:
2160      PRINTD (DBG_QOS|DBG_VCC, "Bad AAL!");
2161      return -EINVAL;
2162  }
2163
2164  // TX traffic parameters
2165
2166  // there are two, interrelated problems here: 1. the reservation of
2167  // PCR is not a binary choice, we are given bounds and/or a
2168  // desirable value; 2. the device is only capable of certain values,
2169  // most of which are not integers. It is almost certainly acceptable
2170  // to be off by a maximum of 1 to 10 cps.
2171
2172  // Pragmatic choice: always store an integral PCR as that which has
2173  // been allocated, even if we allocate a little (or a lot) less,
2174  // after rounding. The actual allocation depends on what we can
2175  // manage with our rate selection algorithm. The rate selection
2176  // algorithm is given an integral PCR and a tolerance and told
2177  // whether it should round the value up or down if the tolerance is
2178  // exceeded; it returns: a) the actual rate selected (rounded up to
2179  // the nearest integer), b) a bit pattern to feed to the timer
2180  // register, and c) a failure value if no applicable rate exists.
2181
2182  // Part of the job is done by atm_pcr_goal which gives us a PCR
2183  // specification which says: EITHER grab the maximum available PCR
2184  // (and perhaps a lower bound which we musn't pass), OR grab this
2185  // amount, rounding down if you have to (and perhaps a lower bound
2186  // which we musn't pass) OR grab this amount, rounding up if you
2187  // have to (and perhaps an upper bound which we musn't pass). If any
2188  // bounds ARE passed we fail. Note that rounding is only rounding to
2189  // match device limitations, we do not round down to satisfy
2190  // bandwidth availability even if this would not violate any given
2191  // lower bound.
2192
2193  // Note: telephony = 64kb/s = 48 byte cell payload @ 500/3 cells/s
2194  // (say) so this is not even a binary fixpoint cell rate (but this
2195  // device can do it). To avoid this sort of hassle we use a
2196  // tolerance parameter (currently fixed at 10 cps).
2197
2198  PRINTD (DBG_QOS, "TX:");
2199
2200  txtp = &qos->txtp;
2201
2202  // set up defaults for no traffic
2203  vcc.tx_rate = 0;
2204  // who knows what would actually happen if you try and send on this?
2205  vcc.tx_xbr_bits = IDLE_RATE_TYPE;
2206  vcc.tx_pcr_bits = CLOCK_DISABLE;
2207#if 0
2208  vcc.tx_scr_bits = CLOCK_DISABLE;
2209  vcc.tx_bucket_bits = 0;
2210#endif
2211
2212  if (txtp->traffic_class != ATM_NONE) {
2213    error = check_max_sdu (vcc.aal, txtp, max_tx_size);
2214    if (error) {
2215      PRINTD (DBG_QOS, "TX max_sdu check failed");
2216      return error;
2217    }
2218
2219    switch (txtp->traffic_class) {
2220      case ATM_UBR: {
2221	// we take "the PCR" as a rate-cap
2222	// not reserved
2223	vcc.tx_rate = 0;
2224	make_rate (dev, 1<<30, round_nearest, &vcc.tx_pcr_bits, NULL);
2225	vcc.tx_xbr_bits = ABR_RATE_TYPE;
2226	break;
2227      }
2228#if 0
2229      case ATM_ABR: {
2230	// reserve min, allow up to max
2231	vcc.tx_rate = 0; // ?
2232	make_rate (dev, 1<<30, round_nearest, &vcc.tx_pcr_bits, 0);
2233	vcc.tx_xbr_bits = ABR_RATE_TYPE;
2234	break;
2235      }
2236#endif
2237      case ATM_CBR: {
2238	int pcr = atm_pcr_goal (txtp);
2239	rounding r;
2240	if (!pcr) {
2241	  // down vs. up, remaining bandwidth vs. unlimited bandwidth!!
2242	  // should really have: once someone gets unlimited bandwidth
2243	  // that no more non-UBR channels can be opened until the
2244	  // unlimited one closes?? For the moment, round_down means
2245	  // greedy people actually get something and not nothing
2246	  r = round_down;
2247	  // slight race (no locking) here so we may get -EAGAIN
2248	  // later; the greedy bastards would deserve it :)
2249	  PRINTD (DBG_QOS, "snatching all remaining TX bandwidth");
2250	  pcr = dev->tx_avail;
2251	} else if (pcr < 0) {
2252	  r = round_down;
2253	  pcr = -pcr;
2254	} else {
2255	  r = round_up;
2256	}
2257	error = make_rate_with_tolerance (dev, pcr, r, 10,
2258					  &vcc.tx_pcr_bits, &vcc.tx_rate);
2259	if (error) {
2260	  PRINTD (DBG_QOS, "could not make rate from TX PCR");
2261	  return error;
2262	}
2263	// not really clear what further checking is needed
2264	error = atm_pcr_check (txtp, vcc.tx_rate);
2265	if (error) {
2266	  PRINTD (DBG_QOS, "TX PCR failed consistency check");
2267	  return error;
2268	}
2269	vcc.tx_xbr_bits = CBR_RATE_TYPE;
2270	break;
2271      }
2272#if 0
2273      case ATM_VBR: {
2274	int pcr = atm_pcr_goal (txtp);
2275	// int scr = atm_scr_goal (txtp);
2276	int scr = pcr/2; // just for fun
2277	unsigned int mbs = 60; // just for fun
2278	rounding pr;
2279	rounding sr;
2280	unsigned int bucket;
2281	if (!pcr) {
2282	  pr = round_nearest;
2283	  pcr = 1<<30;
2284	} else if (pcr < 0) {
2285	  pr = round_down;
2286	  pcr = -pcr;
2287	} else {
2288	  pr = round_up;
2289	}
2290	error = make_rate_with_tolerance (dev, pcr, pr, 10,
2291					  &vcc.tx_pcr_bits, 0);
2292	if (!scr) {
2293	  // see comments for PCR with CBR above
2294	  sr = round_down;
2295	  // slight race (no locking) here so we may get -EAGAIN
2296	  // later; the greedy bastards would deserve it :)
2297	  PRINTD (DBG_QOS, "snatching all remaining TX bandwidth");
2298	  scr = dev->tx_avail;
2299	} else if (scr < 0) {
2300	  sr = round_down;
2301	  scr = -scr;
2302	} else {
2303	  sr = round_up;
2304	}
2305	error = make_rate_with_tolerance (dev, scr, sr, 10,
2306					  &vcc.tx_scr_bits, &vcc.tx_rate);
2307	if (error) {
2308	  PRINTD (DBG_QOS, "could not make rate from TX SCR");
2309	  return error;
2310	}
2311	// not really clear what further checking is needed
2312	// error = atm_scr_check (txtp, vcc.tx_rate);
2313	if (error) {
2314	  PRINTD (DBG_QOS, "TX SCR failed consistency check");
2315	  return error;
2316	}
2317	// bucket calculations (from a piece of paper...) cell bucket
2318	// capacity must be largest integer smaller than m(p-s)/p + 1
2319	// where m = max burst size, p = pcr, s = scr
2320	bucket = mbs*(pcr-scr)/pcr;
2321	if (bucket*pcr != mbs*(pcr-scr))
2322	  bucket += 1;
2323	if (bucket > BUCKET_MAX_SIZE) {
2324	  PRINTD (DBG_QOS, "shrinking bucket from %u to %u",
2325		  bucket, BUCKET_MAX_SIZE);
2326	  bucket = BUCKET_MAX_SIZE;
2327	}
2328	vcc.tx_xbr_bits = VBR_RATE_TYPE;
2329	vcc.tx_bucket_bits = bucket;
2330	break;
2331      }
2332#endif
2333      default: {
2334	PRINTD (DBG_QOS, "unsupported TX traffic class");
2335	return -EINVAL;
2336      }
2337    }
2338  }
2339
2340  // RX traffic parameters
2341
2342  PRINTD (DBG_QOS, "RX:");
2343
2344  rxtp = &qos->rxtp;
2345
2346  // set up defaults for no traffic
2347  vcc.rx_rate = 0;
2348
2349  if (rxtp->traffic_class != ATM_NONE) {
2350    error = check_max_sdu (vcc.aal, rxtp, max_rx_size);
2351    if (error) {
2352      PRINTD (DBG_QOS, "RX max_sdu check failed");
2353      return error;
2354    }
2355    switch (rxtp->traffic_class) {
2356      case ATM_UBR: {
2357	// not reserved
2358	break;
2359      }
2360#if 0
2361      case ATM_ABR: {
2362	// reserve min
2363	vcc.rx_rate = 0; // ?
2364	break;
2365      }
2366#endif
2367      case ATM_CBR: {
2368	int pcr = atm_pcr_goal (rxtp);
2369	if (!pcr) {
2370	  // slight race (no locking) here so we may get -EAGAIN
2371	  // later; the greedy bastards would deserve it :)
2372	  PRINTD (DBG_QOS, "snatching all remaining RX bandwidth");
2373	  pcr = dev->rx_avail;
2374	} else if (pcr < 0) {
2375	  pcr = -pcr;
2376	}
2377	vcc.rx_rate = pcr;
2378	// not really clear what further checking is needed
2379	error = atm_pcr_check (rxtp, vcc.rx_rate);
2380	if (error) {
2381	  PRINTD (DBG_QOS, "RX PCR failed consistency check");
2382	  return error;
2383	}
2384	break;
2385      }
2386#if 0
2387      case ATM_VBR: {
2388	// int scr = atm_scr_goal (rxtp);
2389	int scr = 1<<16; // just for fun
2390	if (!scr) {
2391	  // slight race (no locking) here so we may get -EAGAIN
2392	  // later; the greedy bastards would deserve it :)
2393	  PRINTD (DBG_QOS, "snatching all remaining RX bandwidth");
2394	  scr = dev->rx_avail;
2395	} else if (scr < 0) {
2396	  scr = -scr;
2397	}
2398	vcc.rx_rate = scr;
2399	// not really clear what further checking is needed
2400	// error = atm_scr_check (rxtp, vcc.rx_rate);
2401	if (error) {
2402	  PRINTD (DBG_QOS, "RX SCR failed consistency check");
2403	  return error;
2404	}
2405	break;
2406      }
2407#endif
2408      default: {
2409	PRINTD (DBG_QOS, "unsupported RX traffic class");
2410	return -EINVAL;
2411      }
2412    }
2413  }
2414
2415
2416  // late abort useful for diagnostics
2417  if (vcc.aal != aal5) {
2418    PRINTD (DBG_QOS, "AAL not supported");
2419    return -EINVAL;
2420  }
2421
2422  // get space for our vcc stuff and copy parameters into it
2423  vccp = kmalloc (sizeof(hrz_vcc), GFP_KERNEL);
2424  if (!vccp) {
2425    PRINTK (KERN_ERR, "out of memory!");
2426    return -ENOMEM;
2427  }
2428  *vccp = vcc;
2429
2430  // clear error and grab cell rate resource lock
2431  error = 0;
2432  spin_lock (&dev->rate_lock);
2433
2434  if (vcc.tx_rate > dev->tx_avail) {
2435    PRINTD (DBG_QOS, "not enough TX PCR left");
2436    error = -EAGAIN;
2437  }
2438
2439  if (vcc.rx_rate > dev->rx_avail) {
2440    PRINTD (DBG_QOS, "not enough RX PCR left");
2441    error = -EAGAIN;
2442  }
2443
2444  if (!error) {
2445    // really consume cell rates
2446    dev->tx_avail -= vcc.tx_rate;
2447    dev->rx_avail -= vcc.rx_rate;
2448    PRINTD (DBG_QOS|DBG_VCC, "reserving %u TX PCR and %u RX PCR",
2449	    vcc.tx_rate, vcc.rx_rate);
2450  }
2451
2452  // release lock and exit on error
2453  spin_unlock (&dev->rate_lock);
2454  if (error) {
2455    PRINTD (DBG_QOS|DBG_VCC, "insufficient cell rate resources");
2456    kfree (vccp);
2457    return error;
2458  }
2459
2460  // this is "immediately before allocating the connection identifier
2461  // in hardware" - so long as the next call does not fail :)
2462  set_bit(ATM_VF_ADDR,&atm_vcc->flags);
2463
2464  // any errors here are very serious and should never occur
2465
2466  if (rxtp->traffic_class != ATM_NONE) {
2467    if (dev->rxer[channel]) {
2468      PRINTD (DBG_ERR|DBG_VCC, "VC already open for RX");
2469      error = -EBUSY;
2470    }
2471    if (!error)
2472      error = hrz_open_rx (dev, channel);
2473    if (error) {
2474      kfree (vccp);
2475      return error;
2476    }
2477    // this link allows RX frames through
2478    dev->rxer[channel] = atm_vcc;
2479  }
2480
2481  // success, set elements of atm_vcc
2482  atm_vcc->dev_data = (void *) vccp;
2483
2484  // indicate readiness
2485  set_bit(ATM_VF_READY,&atm_vcc->flags);
2486
2487  return 0;
2488}
2489
2490/********** close VC **********/
2491
2492static void hrz_close (struct atm_vcc * atm_vcc) {
2493  hrz_dev * dev = HRZ_DEV(atm_vcc->dev);
2494  hrz_vcc * vcc = HRZ_VCC(atm_vcc);
2495  u16 channel = vcc->channel;
2496  PRINTD (DBG_VCC|DBG_FLOW, "hrz_close");
2497
2498  // indicate unreadiness
2499  clear_bit(ATM_VF_READY,&atm_vcc->flags);
2500
2501  if (atm_vcc->qos.txtp.traffic_class != ATM_NONE) {
2502    unsigned int i;
2503
2504    // let any TX on this channel that has started complete
2505    // no restart, just keep trying
2506    while (tx_hold (dev))
2507      ;
2508    // remove record of any tx_channel having been setup for this channel
2509    for (i = 0; i < TX_CHANS; ++i)
2510      if (dev->tx_channel_record[i] == channel) {
2511	dev->tx_channel_record[i] = -1;
2512	break;
2513      }
2514    if (dev->last_vc == channel)
2515      dev->tx_last = -1;
2516    tx_release (dev);
2517  }
2518
2519  if (atm_vcc->qos.rxtp.traffic_class != ATM_NONE) {
2520    // disable RXing - it tries quite hard
2521    hrz_close_rx (dev, channel);
2522    // forget the vcc - no more skbs will be pushed
2523    if (atm_vcc != dev->rxer[channel])
2524      PRINTK (KERN_ERR, "%s atm_vcc=%p rxer[channel]=%p",
2525	      "arghhh! we're going to die!",
2526	      atm_vcc, dev->rxer[channel]);
2527    dev->rxer[channel] = NULL;
2528  }
2529
2530  // atomically release our rate reservation
2531  spin_lock (&dev->rate_lock);
2532  PRINTD (DBG_QOS|DBG_VCC, "releasing %u TX PCR and %u RX PCR",
2533	  vcc->tx_rate, vcc->rx_rate);
2534  dev->tx_avail += vcc->tx_rate;
2535  dev->rx_avail += vcc->rx_rate;
2536  spin_unlock (&dev->rate_lock);
2537
2538  // free our structure
2539  kfree (vcc);
2540  // say the VPI/VCI is free again
2541  clear_bit(ATM_VF_ADDR,&atm_vcc->flags);
2542}
2543
2544#if 0
2545static int hrz_getsockopt (struct atm_vcc * atm_vcc, int level, int optname,
2546			   void *optval, int optlen) {
2547  hrz_dev * dev = HRZ_DEV(atm_vcc->dev);
2548  PRINTD (DBG_FLOW|DBG_VCC, "hrz_getsockopt");
2549  switch (level) {
2550    case SOL_SOCKET:
2551      switch (optname) {
2552//	case SO_BCTXOPT:
2553//	  break;
2554//	case SO_BCRXOPT:
2555//	  break;
2556	default:
2557	  return -ENOPROTOOPT;
2558      };
2559      break;
2560  }
2561  return -EINVAL;
2562}
2563
2564static int hrz_setsockopt (struct atm_vcc * atm_vcc, int level, int optname,
2565			   void *optval, unsigned int optlen) {
2566  hrz_dev * dev = HRZ_DEV(atm_vcc->dev);
2567  PRINTD (DBG_FLOW|DBG_VCC, "hrz_setsockopt");
2568  switch (level) {
2569    case SOL_SOCKET:
2570      switch (optname) {
2571//	case SO_BCTXOPT:
2572//	  break;
2573//	case SO_BCRXOPT:
2574//	  break;
2575	default:
2576	  return -ENOPROTOOPT;
2577      };
2578      break;
2579  }
2580  return -EINVAL;
2581}
2582#endif
2583
2584#if 0
2585static int hrz_ioctl (struct atm_dev * atm_dev, unsigned int cmd, void *arg) {
2586  hrz_dev * dev = HRZ_DEV(atm_dev);
2587  PRINTD (DBG_FLOW, "hrz_ioctl");
2588  return -1;
2589}
2590
2591unsigned char hrz_phy_get (struct atm_dev * atm_dev, unsigned long addr) {
2592  hrz_dev * dev = HRZ_DEV(atm_dev);
2593  PRINTD (DBG_FLOW, "hrz_phy_get");
2594  return 0;
2595}
2596
2597static void hrz_phy_put (struct atm_dev * atm_dev, unsigned char value,
2598			 unsigned long addr) {
2599  hrz_dev * dev = HRZ_DEV(atm_dev);
2600  PRINTD (DBG_FLOW, "hrz_phy_put");
2601}
2602
2603static int hrz_change_qos (struct atm_vcc * atm_vcc, struct atm_qos *qos, int flgs) {
2604  hrz_dev * dev = HRZ_DEV(vcc->dev);
2605  PRINTD (DBG_FLOW, "hrz_change_qos");
2606  return -1;
2607}
2608#endif
2609
2610/********** proc file contents **********/
2611
2612static int hrz_proc_read (struct atm_dev * atm_dev, loff_t * pos, char * page) {
2613  hrz_dev * dev = HRZ_DEV(atm_dev);
2614  int left = *pos;
2615  PRINTD (DBG_FLOW, "hrz_proc_read");
2616
2617  /* more diagnostics here? */
2618
2619#if 0
2620  if (!left--) {
2621    unsigned int count = sprintf (page, "vbr buckets:");
2622    unsigned int i;
2623    for (i = 0; i < TX_CHANS; ++i)
2624      count += sprintf (page, " %u/%u",
2625			query_tx_channel_config (dev, i, BUCKET_FULLNESS_ACCESS),
2626			query_tx_channel_config (dev, i, BUCKET_CAPACITY_ACCESS));
2627    count += sprintf (page+count, ".\n");
2628    return count;
2629  }
2630#endif
2631
2632  if (!left--)
2633    return sprintf (page,
2634		    "cells: TX %lu, RX %lu, HEC errors %lu, unassigned %lu.\n",
2635		    dev->tx_cell_count, dev->rx_cell_count,
2636		    dev->hec_error_count, dev->unassigned_cell_count);
2637
2638  if (!left--)
2639    return sprintf (page,
2640		    "free cell buffers: TX %hu, RX %hu+%hu.\n",
2641		    rd_regw (dev, TX_FREE_BUFFER_COUNT_OFF),
2642		    rd_regw (dev, RX_FREE_BUFFER_COUNT_OFF),
2643		    dev->noof_spare_buffers);
2644
2645  if (!left--)
2646    return sprintf (page,
2647		    "cps remaining: TX %u, RX %u\n",
2648		    dev->tx_avail, dev->rx_avail);
2649
2650  return 0;
2651}
2652
2653static const struct atmdev_ops hrz_ops = {
2654  .open	= hrz_open,
2655  .close	= hrz_close,
2656  .send	= hrz_send,
2657  .proc_read	= hrz_proc_read,
2658  .owner	= THIS_MODULE,
2659};
2660
2661static int hrz_probe(struct pci_dev *pci_dev,
2662		     const struct pci_device_id *pci_ent)
2663{
2664	hrz_dev * dev;
2665	int err = 0;
2666
2667	// adapter slot free, read resources from PCI configuration space
2668	u32 iobase = pci_resource_start (pci_dev, 0);
2669	u32 * membase = bus_to_virt (pci_resource_start (pci_dev, 1));
2670	unsigned int irq;
2671	unsigned char lat;
2672
2673	PRINTD (DBG_FLOW, "hrz_probe");
2674
2675	if (pci_enable_device(pci_dev))
2676		return -EINVAL;
2677
2678	/* XXX DEV_LABEL is a guess */
2679	if (!request_region(iobase, HRZ_IO_EXTENT, DEV_LABEL)) {
2680		err = -EINVAL;
2681		goto out_disable;
2682	}
2683
2684	dev = kzalloc(sizeof(hrz_dev), GFP_KERNEL);
2685	if (!dev) {
2686		// perhaps we should be nice: deregister all adapters and abort?
2687		PRINTD(DBG_ERR, "out of memory");
2688		err = -ENOMEM;
2689		goto out_release;
2690	}
2691
2692	pci_set_drvdata(pci_dev, dev);
2693
2694	// grab IRQ and install handler - move this someplace more sensible
2695	irq = pci_dev->irq;
2696	if (request_irq(irq,
2697			interrupt_handler,
2698			IRQF_SHARED, /* irqflags guess */
2699			DEV_LABEL, /* name guess */
2700			dev)) {
2701		PRINTD(DBG_WARN, "request IRQ failed!");
2702		err = -EINVAL;
2703		goto out_free;
2704	}
2705
2706	PRINTD(DBG_INFO, "found Madge ATM adapter (hrz) at: IO %x, IRQ %u, MEM %p",
2707	       iobase, irq, membase);
2708
2709	dev->atm_dev = atm_dev_register(DEV_LABEL, &pci_dev->dev, &hrz_ops, -1,
2710					NULL);
2711	if (!(dev->atm_dev)) {
2712		PRINTD(DBG_ERR, "failed to register Madge ATM adapter");
2713		err = -EINVAL;
2714		goto out_free_irq;
2715	}
2716
2717	PRINTD(DBG_INFO, "registered Madge ATM adapter (no. %d) (%p) at %p",
2718	       dev->atm_dev->number, dev, dev->atm_dev);
2719	dev->atm_dev->dev_data = (void *) dev;
2720	dev->pci_dev = pci_dev;
2721
2722	// enable bus master accesses
2723	pci_set_master(pci_dev);
2724
2725	// frobnicate latency (upwards, usually)
2726	pci_read_config_byte(pci_dev, PCI_LATENCY_TIMER, &lat);
2727	if (pci_lat) {
2728		PRINTD(DBG_INFO, "%s PCI latency timer from %hu to %hu",
2729		       "changing", lat, pci_lat);
2730		pci_write_config_byte(pci_dev, PCI_LATENCY_TIMER, pci_lat);
2731	} else if (lat < MIN_PCI_LATENCY) {
2732		PRINTK(KERN_INFO, "%s PCI latency timer from %hu to %hu",
2733		       "increasing", lat, MIN_PCI_LATENCY);
2734		pci_write_config_byte(pci_dev, PCI_LATENCY_TIMER, MIN_PCI_LATENCY);
2735	}
2736
2737	dev->iobase = iobase;
2738	dev->irq = irq;
2739	dev->membase = membase;
2740
2741	dev->rx_q_entry = dev->rx_q_reset = &memmap->rx_q_entries[0];
2742	dev->rx_q_wrap  = &memmap->rx_q_entries[RX_CHANS-1];
2743
2744	// these next three are performance hacks
2745	dev->last_vc = -1;
2746	dev->tx_last = -1;
2747	dev->tx_idle = 0;
2748
2749	dev->tx_regions = 0;
2750	dev->tx_bytes = 0;
2751	dev->tx_skb = NULL;
2752	dev->tx_iovec = NULL;
2753
2754	dev->tx_cell_count = 0;
2755	dev->rx_cell_count = 0;
2756	dev->hec_error_count = 0;
2757	dev->unassigned_cell_count = 0;
2758
2759	dev->noof_spare_buffers = 0;
2760
2761	{
2762		unsigned int i;
2763		for (i = 0; i < TX_CHANS; ++i)
2764			dev->tx_channel_record[i] = -1;
2765	}
2766
2767	dev->flags = 0;
2768
2769	// Allocate cell rates and remember ASIC version
2770	// Fibre: ATM_OC3_PCR = 1555200000/8/270*260/53 - 29/53
2771	// Copper: (WRONG) we want 6 into the above, close to 25Mb/s
2772	// Copper: (plagarise!) 25600000/8/270*260/53 - n/53
2773
2774	if (hrz_init(dev)) {
2775		// to be really pedantic, this should be ATM_OC3c_PCR
2776		dev->tx_avail = ATM_OC3_PCR;
2777		dev->rx_avail = ATM_OC3_PCR;
2778		set_bit(ultra, &dev->flags); // NOT "|= ultra" !
2779	} else {
2780		dev->tx_avail = ((25600000/8)*26)/(27*53);
2781		dev->rx_avail = ((25600000/8)*26)/(27*53);
2782		PRINTD(DBG_WARN, "Buggy ASIC: no TX bus-mastering.");
2783	}
2784
2785	// rate changes spinlock
2786	spin_lock_init(&dev->rate_lock);
2787
2788	// on-board memory access spinlock; we want atomic reads and
2789	// writes to adapter memory (handles IRQ and SMP)
2790	spin_lock_init(&dev->mem_lock);
2791
2792	init_waitqueue_head(&dev->tx_queue);
2793
2794	// vpi in 0..4, vci in 6..10
2795	dev->atm_dev->ci_range.vpi_bits = vpi_bits;
2796	dev->atm_dev->ci_range.vci_bits = 10-vpi_bits;
2797
2798	init_timer(&dev->housekeeping);
2799	dev->housekeeping.function = do_housekeeping;
2800	dev->housekeeping.data = (unsigned long) dev;
2801	mod_timer(&dev->housekeeping, jiffies);
2802
2803out:
2804	return err;
2805
2806out_free_irq:
2807	free_irq(dev->irq, dev);
2808out_free:
2809	kfree(dev);
2810out_release:
2811	release_region(iobase, HRZ_IO_EXTENT);
2812out_disable:
2813	pci_disable_device(pci_dev);
2814	goto out;
2815}
2816
2817static void hrz_remove_one(struct pci_dev *pci_dev)
2818{
2819	hrz_dev *dev;
2820
2821	dev = pci_get_drvdata(pci_dev);
2822
2823	PRINTD(DBG_INFO, "closing %p (atm_dev = %p)", dev, dev->atm_dev);
2824	del_timer_sync(&dev->housekeeping);
2825	hrz_reset(dev);
2826	atm_dev_deregister(dev->atm_dev);
2827	free_irq(dev->irq, dev);
2828	release_region(dev->iobase, HRZ_IO_EXTENT);
2829	kfree(dev);
2830
2831	pci_disable_device(pci_dev);
2832}
2833
2834static void __init hrz_check_args (void) {
2835#ifdef DEBUG_HORIZON
2836  PRINTK (KERN_NOTICE, "debug bitmap is %hx", debug &= DBG_MASK);
2837#else
2838  if (debug)
2839    PRINTK (KERN_NOTICE, "no debug support in this image");
2840#endif
2841
2842  if (vpi_bits > HRZ_MAX_VPI)
2843    PRINTK (KERN_ERR, "vpi_bits has been limited to %hu",
2844	    vpi_bits = HRZ_MAX_VPI);
2845
2846  if (max_tx_size < 0 || max_tx_size > TX_AAL5_LIMIT)
2847    PRINTK (KERN_NOTICE, "max_tx_size has been limited to %hu",
2848	    max_tx_size = TX_AAL5_LIMIT);
2849
2850  if (max_rx_size < 0 || max_rx_size > RX_AAL5_LIMIT)
2851    PRINTK (KERN_NOTICE, "max_rx_size has been limited to %hu",
2852	    max_rx_size = RX_AAL5_LIMIT);
2853
2854  return;
2855}
2856
2857MODULE_AUTHOR(maintainer_string);
2858MODULE_DESCRIPTION(description_string);
2859MODULE_LICENSE("GPL");
2860module_param(debug, ushort, 0644);
2861module_param(vpi_bits, ushort, 0);
2862module_param(max_tx_size, int, 0);
2863module_param(max_rx_size, int, 0);
2864module_param(pci_lat, byte, 0);
2865MODULE_PARM_DESC(debug, "debug bitmap, see .h file");
2866MODULE_PARM_DESC(vpi_bits, "number of bits (0..4) to allocate to VPIs");
2867MODULE_PARM_DESC(max_tx_size, "maximum size of TX AAL5 frames");
2868MODULE_PARM_DESC(max_rx_size, "maximum size of RX AAL5 frames");
2869MODULE_PARM_DESC(pci_lat, "PCI latency in bus cycles");
2870
2871static struct pci_device_id hrz_pci_tbl[] = {
2872	{ PCI_VENDOR_ID_MADGE, PCI_DEVICE_ID_MADGE_HORIZON, PCI_ANY_ID, PCI_ANY_ID,
2873	  0, 0, 0 },
2874	{ 0, }
2875};
2876
2877MODULE_DEVICE_TABLE(pci, hrz_pci_tbl);
2878
2879static struct pci_driver hrz_driver = {
2880	.name =		"horizon",
2881	.probe =	hrz_probe,
2882	.remove =	hrz_remove_one,
2883	.id_table =	hrz_pci_tbl,
2884};
2885
2886/********** module entry **********/
2887
2888static int __init hrz_module_init (void) {
2889  // sanity check - cast is needed since printk does not support %Zu
2890  if (sizeof(struct MEMMAP) != 128*1024/4) {
2891    PRINTK (KERN_ERR, "Fix struct MEMMAP (is %lu fakewords).",
2892	    (unsigned long) sizeof(struct MEMMAP));
2893    return -ENOMEM;
2894  }
2895
2896  show_version();
2897
2898  // check arguments
2899  hrz_check_args();
2900
2901  // get the juice
2902  return pci_register_driver(&hrz_driver);
2903}
2904
2905/********** module exit **********/
2906
2907static void __exit hrz_module_exit (void) {
2908  PRINTD (DBG_FLOW, "cleanup_module");
2909
2910  pci_unregister_driver(&hrz_driver);
2911}
2912
2913module_init(hrz_module_init);
2914module_exit(hrz_module_exit);
2915