1/* mac_esp.c: ESP front-end for Macintosh Quadra systems.
2 *
3 * Adapted from jazz_esp.c and the old mac_esp.c.
4 *
5 * The pseudo DMA algorithm is based on the one used in NetBSD.
6 * See sys/arch/mac68k/obio/esp.c for some background information.
7 *
8 * Copyright (C) 2007-2008 Finn Thain
9 */
10
11#include <linux/kernel.h>
12#include <linux/types.h>
13#include <linux/module.h>
14#include <linux/init.h>
15#include <linux/interrupt.h>
16#include <linux/platform_device.h>
17#include <linux/dma-mapping.h>
18#include <linux/scatterlist.h>
19#include <linux/delay.h>
20#include <linux/io.h>
21#include <linux/nubus.h>
22#include <linux/slab.h>
23
24#include <asm/irq.h>
25#include <asm/dma.h>
26#include <asm/macints.h>
27#include <asm/macintosh.h>
28#include <asm/mac_via.h>
29
30#include <scsi/scsi_host.h>
31
32#include "esp_scsi.h"
33
34#define DRV_MODULE_NAME     "mac_esp"
35#define PFX                 DRV_MODULE_NAME ": "
36#define DRV_VERSION         "1.000"
37#define DRV_MODULE_RELDATE  "Sept 15, 2007"
38
39#define MAC_ESP_IO_BASE          0x50F00000
40#define MAC_ESP_REGS_QUADRA      (MAC_ESP_IO_BASE + 0x10000)
41#define MAC_ESP_REGS_QUADRA2     (MAC_ESP_IO_BASE + 0xF000)
42#define MAC_ESP_REGS_QUADRA3     (MAC_ESP_IO_BASE + 0x18000)
43#define MAC_ESP_REGS_SPACING     0x402
44#define MAC_ESP_PDMA_REG         0xF9800024
45#define MAC_ESP_PDMA_REG_SPACING 0x4
46#define MAC_ESP_PDMA_IO_OFFSET   0x100
47
48#define esp_read8(REG)		mac_esp_read8(esp, REG)
49#define esp_write8(VAL, REG)	mac_esp_write8(esp, VAL, REG)
50
51struct mac_esp_priv {
52	struct esp *esp;
53	void __iomem *pdma_regs;
54	void __iomem *pdma_io;
55	int error;
56};
57static struct esp *esp_chips[2];
58
59#define MAC_ESP_GET_PRIV(esp) ((struct mac_esp_priv *) \
60			       platform_get_drvdata((struct platform_device *) \
61						    (esp->dev)))
62
63static inline void mac_esp_write8(struct esp *esp, u8 val, unsigned long reg)
64{
65	nubus_writeb(val, esp->regs + reg * 16);
66}
67
68static inline u8 mac_esp_read8(struct esp *esp, unsigned long reg)
69{
70	return nubus_readb(esp->regs + reg * 16);
71}
72
73/* For pseudo DMA and PIO we need the virtual address
74 * so this address mapping is the identity mapping.
75 */
76
77static dma_addr_t mac_esp_map_single(struct esp *esp, void *buf,
78				     size_t sz, int dir)
79{
80	return (dma_addr_t)buf;
81}
82
83static int mac_esp_map_sg(struct esp *esp, struct scatterlist *sg,
84			  int num_sg, int dir)
85{
86	int i;
87
88	for (i = 0; i < num_sg; i++)
89		sg[i].dma_address = (u32)sg_virt(&sg[i]);
90	return num_sg;
91}
92
93static void mac_esp_unmap_single(struct esp *esp, dma_addr_t addr,
94				 size_t sz, int dir)
95{
96	/* Nothing to do. */
97}
98
99static void mac_esp_unmap_sg(struct esp *esp, struct scatterlist *sg,
100			     int num_sg, int dir)
101{
102	/* Nothing to do. */
103}
104
105static void mac_esp_reset_dma(struct esp *esp)
106{
107	/* Nothing to do. */
108}
109
110static void mac_esp_dma_drain(struct esp *esp)
111{
112	/* Nothing to do. */
113}
114
115static void mac_esp_dma_invalidate(struct esp *esp)
116{
117	/* Nothing to do. */
118}
119
120static int mac_esp_dma_error(struct esp *esp)
121{
122	return MAC_ESP_GET_PRIV(esp)->error;
123}
124
125static inline int mac_esp_wait_for_empty_fifo(struct esp *esp)
126{
127	struct mac_esp_priv *mep = MAC_ESP_GET_PRIV(esp);
128	int i = 500000;
129
130	do {
131		if (!(esp_read8(ESP_FFLAGS) & ESP_FF_FBYTES))
132			return 0;
133
134		if (esp_read8(ESP_STATUS) & ESP_STAT_INTR)
135			return 1;
136
137		udelay(2);
138	} while (--i);
139
140	printk(KERN_ERR PFX "FIFO is not empty (sreg %02x)\n",
141	       esp_read8(ESP_STATUS));
142	mep->error = 1;
143	return 1;
144}
145
146static inline int mac_esp_wait_for_dreq(struct esp *esp)
147{
148	struct mac_esp_priv *mep = MAC_ESP_GET_PRIV(esp);
149	int i = 500000;
150
151	do {
152		if (mep->pdma_regs == NULL) {
153			if (via2_scsi_drq_pending())
154				return 0;
155		} else {
156			if (nubus_readl(mep->pdma_regs) & 0x200)
157				return 0;
158		}
159
160		if (esp_read8(ESP_STATUS) & ESP_STAT_INTR)
161			return 1;
162
163		udelay(2);
164	} while (--i);
165
166	printk(KERN_ERR PFX "PDMA timeout (sreg %02x)\n",
167	       esp_read8(ESP_STATUS));
168	mep->error = 1;
169	return 1;
170}
171
172#define MAC_ESP_PDMA_LOOP(operands) \
173	asm volatile ( \
174	     "       tstw %1                   \n" \
175	     "       jbeq 20f                  \n" \
176	     "1:     movew " operands "        \n" \
177	     "2:     movew " operands "        \n" \
178	     "3:     movew " operands "        \n" \
179	     "4:     movew " operands "        \n" \
180	     "5:     movew " operands "        \n" \
181	     "6:     movew " operands "        \n" \
182	     "7:     movew " operands "        \n" \
183	     "8:     movew " operands "        \n" \
184	     "9:     movew " operands "        \n" \
185	     "10:    movew " operands "        \n" \
186	     "11:    movew " operands "        \n" \
187	     "12:    movew " operands "        \n" \
188	     "13:    movew " operands "        \n" \
189	     "14:    movew " operands "        \n" \
190	     "15:    movew " operands "        \n" \
191	     "16:    movew " operands "        \n" \
192	     "       subqw #1,%1               \n" \
193	     "       jbne 1b                   \n" \
194	     "20:    tstw %2                   \n" \
195	     "       jbeq 30f                  \n" \
196	     "21:    movew " operands "        \n" \
197	     "       subqw #1,%2               \n" \
198	     "       jbne 21b                  \n" \
199	     "30:    tstw %3                   \n" \
200	     "       jbeq 40f                  \n" \
201	     "31:    moveb " operands "        \n" \
202	     "32:    nop                       \n" \
203	     "40:                              \n" \
204	     "                                 \n" \
205	     "       .section __ex_table,\"a\" \n" \
206	     "       .align  4                 \n" \
207	     "       .long   1b,40b            \n" \
208	     "       .long   2b,40b            \n" \
209	     "       .long   3b,40b            \n" \
210	     "       .long   4b,40b            \n" \
211	     "       .long   5b,40b            \n" \
212	     "       .long   6b,40b            \n" \
213	     "       .long   7b,40b            \n" \
214	     "       .long   8b,40b            \n" \
215	     "       .long   9b,40b            \n" \
216	     "       .long  10b,40b            \n" \
217	     "       .long  11b,40b            \n" \
218	     "       .long  12b,40b            \n" \
219	     "       .long  13b,40b            \n" \
220	     "       .long  14b,40b            \n" \
221	     "       .long  15b,40b            \n" \
222	     "       .long  16b,40b            \n" \
223	     "       .long  21b,40b            \n" \
224	     "       .long  31b,40b            \n" \
225	     "       .long  32b,40b            \n" \
226	     "       .previous                 \n" \
227	     : "+a" (addr), "+r" (count32), "+r" (count2) \
228	     : "g" (count1), "a" (mep->pdma_io))
229
230static void mac_esp_send_pdma_cmd(struct esp *esp, u32 addr, u32 esp_count,
231				  u32 dma_count, int write, u8 cmd)
232{
233	struct mac_esp_priv *mep = MAC_ESP_GET_PRIV(esp);
234
235	mep->error = 0;
236
237	if (!write)
238		scsi_esp_cmd(esp, ESP_CMD_FLUSH);
239
240	esp_write8((esp_count >> 0) & 0xFF, ESP_TCLOW);
241	esp_write8((esp_count >> 8) & 0xFF, ESP_TCMED);
242
243	scsi_esp_cmd(esp, cmd);
244
245	do {
246		unsigned int count32 = esp_count >> 5;
247		unsigned int count2 = (esp_count & 0x1F) >> 1;
248		unsigned int count1 = esp_count & 1;
249		unsigned int start_addr = addr;
250
251		if (mac_esp_wait_for_dreq(esp))
252			break;
253
254		if (write) {
255			MAC_ESP_PDMA_LOOP("%4@,%0@+");
256
257			esp_count -= addr - start_addr;
258		} else {
259			unsigned int n;
260
261			MAC_ESP_PDMA_LOOP("%0@+,%4@");
262
263			if (mac_esp_wait_for_empty_fifo(esp))
264				break;
265
266			n = (esp_read8(ESP_TCMED) << 8) + esp_read8(ESP_TCLOW);
267			addr = start_addr + esp_count - n;
268			esp_count = n;
269		}
270	} while (esp_count);
271}
272
273/*
274 * Programmed IO routines follow.
275 */
276
277static inline unsigned int mac_esp_wait_for_fifo(struct esp *esp)
278{
279	int i = 500000;
280
281	do {
282		unsigned int fbytes = esp_read8(ESP_FFLAGS) & ESP_FF_FBYTES;
283
284		if (fbytes)
285			return fbytes;
286
287		udelay(2);
288	} while (--i);
289
290	printk(KERN_ERR PFX "FIFO is empty (sreg %02x)\n",
291	       esp_read8(ESP_STATUS));
292	return 0;
293}
294
295static inline int mac_esp_wait_for_intr(struct esp *esp)
296{
297	struct mac_esp_priv *mep = MAC_ESP_GET_PRIV(esp);
298	int i = 500000;
299
300	do {
301		esp->sreg = esp_read8(ESP_STATUS);
302		if (esp->sreg & ESP_STAT_INTR)
303			return 0;
304
305		udelay(2);
306	} while (--i);
307
308	printk(KERN_ERR PFX "IRQ timeout (sreg %02x)\n", esp->sreg);
309	mep->error = 1;
310	return 1;
311}
312
313#define MAC_ESP_PIO_LOOP(operands, reg1) \
314	asm volatile ( \
315	     "1:     moveb " operands " \n" \
316	     "       subqw #1,%1        \n" \
317	     "       jbne 1b            \n" \
318	     : "+a" (addr), "+r" (reg1) \
319	     : "a" (fifo))
320
321#define MAC_ESP_PIO_FILL(operands, reg1) \
322	asm volatile ( \
323	     "       moveb " operands " \n" \
324	     "       moveb " operands " \n" \
325	     "       moveb " operands " \n" \
326	     "       moveb " operands " \n" \
327	     "       moveb " operands " \n" \
328	     "       moveb " operands " \n" \
329	     "       moveb " operands " \n" \
330	     "       moveb " operands " \n" \
331	     "       moveb " operands " \n" \
332	     "       moveb " operands " \n" \
333	     "       moveb " operands " \n" \
334	     "       moveb " operands " \n" \
335	     "       moveb " operands " \n" \
336	     "       moveb " operands " \n" \
337	     "       moveb " operands " \n" \
338	     "       moveb " operands " \n" \
339	     "       subqw #8,%1        \n" \
340	     "       subqw #8,%1        \n" \
341	     : "+a" (addr), "+r" (reg1) \
342	     : "a" (fifo))
343
344#define MAC_ESP_FIFO_SIZE 16
345
346static void mac_esp_send_pio_cmd(struct esp *esp, u32 addr, u32 esp_count,
347				 u32 dma_count, int write, u8 cmd)
348{
349	struct mac_esp_priv *mep = MAC_ESP_GET_PRIV(esp);
350	u8 *fifo = esp->regs + ESP_FDATA * 16;
351
352	cmd &= ~ESP_CMD_DMA;
353	mep->error = 0;
354
355	if (write) {
356		scsi_esp_cmd(esp, cmd);
357
358		while (1) {
359			unsigned int n;
360
361			n = mac_esp_wait_for_fifo(esp);
362			if (!n)
363				break;
364
365			if (n > esp_count)
366				n = esp_count;
367			esp_count -= n;
368
369			MAC_ESP_PIO_LOOP("%2@,%0@+", n);
370
371			if (!esp_count)
372				break;
373
374			if (mac_esp_wait_for_intr(esp))
375				break;
376
377			if (((esp->sreg & ESP_STAT_PMASK) != ESP_DIP) &&
378			    ((esp->sreg & ESP_STAT_PMASK) != ESP_MIP))
379				break;
380
381			esp->ireg = esp_read8(ESP_INTRPT);
382			if ((esp->ireg & (ESP_INTR_DC | ESP_INTR_BSERV)) !=
383			    ESP_INTR_BSERV)
384				break;
385
386			scsi_esp_cmd(esp, ESP_CMD_TI);
387		}
388	} else {
389		scsi_esp_cmd(esp, ESP_CMD_FLUSH);
390
391		if (esp_count >= MAC_ESP_FIFO_SIZE)
392			MAC_ESP_PIO_FILL("%0@+,%2@", esp_count);
393		else
394			MAC_ESP_PIO_LOOP("%0@+,%2@", esp_count);
395
396		scsi_esp_cmd(esp, cmd);
397
398		while (esp_count) {
399			unsigned int n;
400
401			if (mac_esp_wait_for_intr(esp))
402				break;
403
404			if (((esp->sreg & ESP_STAT_PMASK) != ESP_DOP) &&
405			    ((esp->sreg & ESP_STAT_PMASK) != ESP_MOP))
406				break;
407
408			esp->ireg = esp_read8(ESP_INTRPT);
409			if ((esp->ireg & (ESP_INTR_DC | ESP_INTR_BSERV)) !=
410			    ESP_INTR_BSERV)
411				break;
412
413			n = MAC_ESP_FIFO_SIZE -
414			    (esp_read8(ESP_FFLAGS) & ESP_FF_FBYTES);
415			if (n > esp_count)
416				n = esp_count;
417
418			if (n == MAC_ESP_FIFO_SIZE) {
419				MAC_ESP_PIO_FILL("%0@+,%2@", esp_count);
420			} else {
421				esp_count -= n;
422				MAC_ESP_PIO_LOOP("%0@+,%2@", n);
423			}
424
425			scsi_esp_cmd(esp, ESP_CMD_TI);
426		}
427	}
428}
429
430static int mac_esp_irq_pending(struct esp *esp)
431{
432	if (esp_read8(ESP_STATUS) & ESP_STAT_INTR)
433		return 1;
434	return 0;
435}
436
437static u32 mac_esp_dma_length_limit(struct esp *esp, u32 dma_addr, u32 dma_len)
438{
439	return dma_len > 0xFFFF ? 0xFFFF : dma_len;
440}
441
442static irqreturn_t mac_scsi_esp_intr(int irq, void *dev_id)
443{
444	int got_intr;
445
446	/*
447	 * This is an edge triggered IRQ, so we have to be careful to
448	 * avoid missing a transition when it is shared by two ESP devices.
449	 */
450
451	do {
452		got_intr = 0;
453		if (esp_chips[0] &&
454		    (mac_esp_read8(esp_chips[0], ESP_STATUS) & ESP_STAT_INTR)) {
455			(void)scsi_esp_intr(irq, esp_chips[0]);
456			got_intr = 1;
457		}
458		if (esp_chips[1] &&
459		    (mac_esp_read8(esp_chips[1], ESP_STATUS) & ESP_STAT_INTR)) {
460			(void)scsi_esp_intr(irq, esp_chips[1]);
461			got_intr = 1;
462		}
463	} while (got_intr);
464
465	return IRQ_HANDLED;
466}
467
468static struct esp_driver_ops mac_esp_ops = {
469	.esp_write8       = mac_esp_write8,
470	.esp_read8        = mac_esp_read8,
471	.map_single       = mac_esp_map_single,
472	.map_sg           = mac_esp_map_sg,
473	.unmap_single     = mac_esp_unmap_single,
474	.unmap_sg         = mac_esp_unmap_sg,
475	.irq_pending      = mac_esp_irq_pending,
476	.dma_length_limit = mac_esp_dma_length_limit,
477	.reset_dma        = mac_esp_reset_dma,
478	.dma_drain        = mac_esp_dma_drain,
479	.dma_invalidate   = mac_esp_dma_invalidate,
480	.send_dma_cmd     = mac_esp_send_pdma_cmd,
481	.dma_error        = mac_esp_dma_error,
482};
483
484static int esp_mac_probe(struct platform_device *dev)
485{
486	struct scsi_host_template *tpnt = &scsi_esp_template;
487	struct Scsi_Host *host;
488	struct esp *esp;
489	int err;
490	struct mac_esp_priv *mep;
491
492	if (!MACH_IS_MAC)
493		return -ENODEV;
494
495	if (dev->id > 1)
496		return -ENODEV;
497
498	host = scsi_host_alloc(tpnt, sizeof(struct esp));
499
500	err = -ENOMEM;
501	if (!host)
502		goto fail;
503
504	host->max_id = 8;
505	host->use_clustering = DISABLE_CLUSTERING;
506	esp = shost_priv(host);
507
508	esp->host = host;
509	esp->dev = dev;
510
511	esp->command_block = kzalloc(16, GFP_KERNEL);
512	if (!esp->command_block)
513		goto fail_unlink;
514	esp->command_block_dma = (dma_addr_t)esp->command_block;
515
516	esp->scsi_id = 7;
517	host->this_id = esp->scsi_id;
518	esp->scsi_id_mask = 1 << esp->scsi_id;
519
520	mep = kzalloc(sizeof(struct mac_esp_priv), GFP_KERNEL);
521	if (!mep)
522		goto fail_free_command_block;
523	mep->esp = esp;
524	platform_set_drvdata(dev, mep);
525
526	switch (macintosh_config->scsi_type) {
527	case MAC_SCSI_QUADRA:
528		esp->cfreq     = 16500000;
529		esp->regs      = (void __iomem *)MAC_ESP_REGS_QUADRA;
530		mep->pdma_io   = esp->regs + MAC_ESP_PDMA_IO_OFFSET;
531		mep->pdma_regs = NULL;
532		break;
533	case MAC_SCSI_QUADRA2:
534		esp->cfreq     = 25000000;
535		esp->regs      = (void __iomem *)(MAC_ESP_REGS_QUADRA2 +
536				 dev->id * MAC_ESP_REGS_SPACING);
537		mep->pdma_io   = esp->regs + MAC_ESP_PDMA_IO_OFFSET;
538		mep->pdma_regs = (void __iomem *)(MAC_ESP_PDMA_REG +
539				 dev->id * MAC_ESP_PDMA_REG_SPACING);
540		nubus_writel(0x1d1, mep->pdma_regs);
541		break;
542	case MAC_SCSI_QUADRA3:
543		/* These quadras have a real DMA controller (the PSC) but we
544		 * don't know how to drive it so we must use PIO instead.
545		 */
546		esp->cfreq     = 25000000;
547		esp->regs      = (void __iomem *)MAC_ESP_REGS_QUADRA3;
548		mep->pdma_io   = NULL;
549		mep->pdma_regs = NULL;
550		break;
551	}
552
553	esp->ops = &mac_esp_ops;
554	if (mep->pdma_io == NULL) {
555		printk(KERN_INFO PFX "using PIO for controller %d\n", dev->id);
556		esp_write8(0, ESP_TCLOW);
557		esp_write8(0, ESP_TCMED);
558		esp->flags = ESP_FLAG_DISABLE_SYNC;
559		mac_esp_ops.send_dma_cmd = mac_esp_send_pio_cmd;
560	} else {
561		printk(KERN_INFO PFX "using PDMA for controller %d\n", dev->id);
562	}
563
564	host->irq = IRQ_MAC_SCSI;
565	esp_chips[dev->id] = esp;
566	mb();
567	if (esp_chips[!dev->id] == NULL) {
568		err = request_irq(host->irq, mac_scsi_esp_intr, 0, "ESP", NULL);
569		if (err < 0) {
570			esp_chips[dev->id] = NULL;
571			goto fail_free_priv;
572		}
573	}
574
575	err = scsi_esp_register(esp, &dev->dev);
576	if (err)
577		goto fail_free_irq;
578
579	return 0;
580
581fail_free_irq:
582	if (esp_chips[!dev->id] == NULL)
583		free_irq(host->irq, esp);
584fail_free_priv:
585	kfree(mep);
586fail_free_command_block:
587	kfree(esp->command_block);
588fail_unlink:
589	scsi_host_put(host);
590fail:
591	return err;
592}
593
594static int esp_mac_remove(struct platform_device *dev)
595{
596	struct mac_esp_priv *mep = platform_get_drvdata(dev);
597	struct esp *esp = mep->esp;
598	unsigned int irq = esp->host->irq;
599
600	scsi_esp_unregister(esp);
601
602	esp_chips[dev->id] = NULL;
603	if (!(esp_chips[0] || esp_chips[1]))
604		free_irq(irq, NULL);
605
606	kfree(mep);
607
608	kfree(esp->command_block);
609
610	scsi_host_put(esp->host);
611
612	return 0;
613}
614
615static struct platform_driver esp_mac_driver = {
616	.probe    = esp_mac_probe,
617	.remove   = esp_mac_remove,
618	.driver   = {
619		.name	= DRV_MODULE_NAME,
620	},
621};
622
623static int __init mac_esp_init(void)
624{
625	return platform_driver_register(&esp_mac_driver);
626}
627
628static void __exit mac_esp_exit(void)
629{
630	platform_driver_unregister(&esp_mac_driver);
631}
632
633MODULE_DESCRIPTION("Mac ESP SCSI driver");
634MODULE_AUTHOR("Finn Thain <fthain@telegraphics.com.au>");
635MODULE_LICENSE("GPL v2");
636MODULE_VERSION(DRV_VERSION);
637MODULE_ALIAS("platform:" DRV_MODULE_NAME);
638
639module_init(mac_esp_init);
640module_exit(mac_esp_exit);
641