1/*
2 * Isochronous I/O functionality:
3 *   - Isochronous DMA context management
4 *   - Isochronous bus resource management (channels, bandwidth), client side
5 *
6 * Copyright (C) 2006 Kristian Hoegsberg <krh@bitplanet.net>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software Foundation,
20 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
21 */
22
23#include <linux/dma-mapping.h>
24#include <linux/errno.h>
25#include <linux/firewire.h>
26#include <linux/firewire-constants.h>
27#include <linux/kernel.h>
28#include <linux/mm.h>
29#include <linux/slab.h>
30#include <linux/spinlock.h>
31#include <linux/vmalloc.h>
32#include <linux/export.h>
33
34#include <asm/byteorder.h>
35
36#include "core.h"
37
38/*
39 * Isochronous DMA context management
40 */
41
42int fw_iso_buffer_alloc(struct fw_iso_buffer *buffer, int page_count)
43{
44	int i;
45
46	buffer->page_count = 0;
47	buffer->page_count_mapped = 0;
48	buffer->pages = kmalloc(page_count * sizeof(buffer->pages[0]),
49				GFP_KERNEL);
50	if (buffer->pages == NULL)
51		return -ENOMEM;
52
53	for (i = 0; i < page_count; i++) {
54		buffer->pages[i] = alloc_page(GFP_KERNEL | GFP_DMA32 | __GFP_ZERO);
55		if (buffer->pages[i] == NULL)
56			break;
57	}
58	buffer->page_count = i;
59	if (i < page_count) {
60		fw_iso_buffer_destroy(buffer, NULL);
61		return -ENOMEM;
62	}
63
64	return 0;
65}
66
67int fw_iso_buffer_map_dma(struct fw_iso_buffer *buffer, struct fw_card *card,
68			  enum dma_data_direction direction)
69{
70	dma_addr_t address;
71	int i;
72
73	buffer->direction = direction;
74
75	for (i = 0; i < buffer->page_count; i++) {
76		address = dma_map_page(card->device, buffer->pages[i],
77				       0, PAGE_SIZE, direction);
78		if (dma_mapping_error(card->device, address))
79			break;
80
81		set_page_private(buffer->pages[i], address);
82	}
83	buffer->page_count_mapped = i;
84	if (i < buffer->page_count)
85		return -ENOMEM;
86
87	return 0;
88}
89
90int fw_iso_buffer_init(struct fw_iso_buffer *buffer, struct fw_card *card,
91		       int page_count, enum dma_data_direction direction)
92{
93	int ret;
94
95	ret = fw_iso_buffer_alloc(buffer, page_count);
96	if (ret < 0)
97		return ret;
98
99	ret = fw_iso_buffer_map_dma(buffer, card, direction);
100	if (ret < 0)
101		fw_iso_buffer_destroy(buffer, card);
102
103	return ret;
104}
105EXPORT_SYMBOL(fw_iso_buffer_init);
106
107int fw_iso_buffer_map_vma(struct fw_iso_buffer *buffer,
108			  struct vm_area_struct *vma)
109{
110	unsigned long uaddr;
111	int i, err;
112
113	uaddr = vma->vm_start;
114	for (i = 0; i < buffer->page_count; i++) {
115		err = vm_insert_page(vma, uaddr, buffer->pages[i]);
116		if (err)
117			return err;
118
119		uaddr += PAGE_SIZE;
120	}
121
122	return 0;
123}
124
125void fw_iso_buffer_destroy(struct fw_iso_buffer *buffer,
126			   struct fw_card *card)
127{
128	int i;
129	dma_addr_t address;
130
131	for (i = 0; i < buffer->page_count_mapped; i++) {
132		address = page_private(buffer->pages[i]);
133		dma_unmap_page(card->device, address,
134			       PAGE_SIZE, buffer->direction);
135	}
136	for (i = 0; i < buffer->page_count; i++)
137		__free_page(buffer->pages[i]);
138
139	kfree(buffer->pages);
140	buffer->pages = NULL;
141	buffer->page_count = 0;
142	buffer->page_count_mapped = 0;
143}
144EXPORT_SYMBOL(fw_iso_buffer_destroy);
145
146/* Convert DMA address to offset into virtually contiguous buffer. */
147size_t fw_iso_buffer_lookup(struct fw_iso_buffer *buffer, dma_addr_t completed)
148{
149	size_t i;
150	dma_addr_t address;
151	ssize_t offset;
152
153	for (i = 0; i < buffer->page_count; i++) {
154		address = page_private(buffer->pages[i]);
155		offset = (ssize_t)completed - (ssize_t)address;
156		if (offset > 0 && offset <= PAGE_SIZE)
157			return (i << PAGE_SHIFT) + offset;
158	}
159
160	return 0;
161}
162
163struct fw_iso_context *fw_iso_context_create(struct fw_card *card,
164		int type, int channel, int speed, size_t header_size,
165		fw_iso_callback_t callback, void *callback_data)
166{
167	struct fw_iso_context *ctx;
168
169	ctx = card->driver->allocate_iso_context(card,
170						 type, channel, header_size);
171	if (IS_ERR(ctx))
172		return ctx;
173
174	ctx->card = card;
175	ctx->type = type;
176	ctx->channel = channel;
177	ctx->speed = speed;
178	ctx->header_size = header_size;
179	ctx->callback.sc = callback;
180	ctx->callback_data = callback_data;
181
182	return ctx;
183}
184EXPORT_SYMBOL(fw_iso_context_create);
185
186void fw_iso_context_destroy(struct fw_iso_context *ctx)
187{
188	ctx->card->driver->free_iso_context(ctx);
189}
190EXPORT_SYMBOL(fw_iso_context_destroy);
191
192int fw_iso_context_start(struct fw_iso_context *ctx,
193			 int cycle, int sync, int tags)
194{
195	return ctx->card->driver->start_iso(ctx, cycle, sync, tags);
196}
197EXPORT_SYMBOL(fw_iso_context_start);
198
199int fw_iso_context_set_channels(struct fw_iso_context *ctx, u64 *channels)
200{
201	return ctx->card->driver->set_iso_channels(ctx, channels);
202}
203
204int fw_iso_context_queue(struct fw_iso_context *ctx,
205			 struct fw_iso_packet *packet,
206			 struct fw_iso_buffer *buffer,
207			 unsigned long payload)
208{
209	return ctx->card->driver->queue_iso(ctx, packet, buffer, payload);
210}
211EXPORT_SYMBOL(fw_iso_context_queue);
212
213void fw_iso_context_queue_flush(struct fw_iso_context *ctx)
214{
215	ctx->card->driver->flush_queue_iso(ctx);
216}
217EXPORT_SYMBOL(fw_iso_context_queue_flush);
218
219int fw_iso_context_flush_completions(struct fw_iso_context *ctx)
220{
221	return ctx->card->driver->flush_iso_completions(ctx);
222}
223EXPORT_SYMBOL(fw_iso_context_flush_completions);
224
225int fw_iso_context_stop(struct fw_iso_context *ctx)
226{
227	return ctx->card->driver->stop_iso(ctx);
228}
229EXPORT_SYMBOL(fw_iso_context_stop);
230
231/*
232 * Isochronous bus resource management (channels, bandwidth), client side
233 */
234
235static int manage_bandwidth(struct fw_card *card, int irm_id, int generation,
236			    int bandwidth, bool allocate)
237{
238	int try, new, old = allocate ? BANDWIDTH_AVAILABLE_INITIAL : 0;
239	__be32 data[2];
240
241	/*
242	 * On a 1394a IRM with low contention, try < 1 is enough.
243	 * On a 1394-1995 IRM, we need at least try < 2.
244	 * Let's just do try < 5.
245	 */
246	for (try = 0; try < 5; try++) {
247		new = allocate ? old - bandwidth : old + bandwidth;
248		if (new < 0 || new > BANDWIDTH_AVAILABLE_INITIAL)
249			return -EBUSY;
250
251		data[0] = cpu_to_be32(old);
252		data[1] = cpu_to_be32(new);
253		switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
254				irm_id, generation, SCODE_100,
255				CSR_REGISTER_BASE + CSR_BANDWIDTH_AVAILABLE,
256				data, 8)) {
257		case RCODE_GENERATION:
258			/* A generation change frees all bandwidth. */
259			return allocate ? -EAGAIN : bandwidth;
260
261		case RCODE_COMPLETE:
262			if (be32_to_cpup(data) == old)
263				return bandwidth;
264
265			old = be32_to_cpup(data);
266			/* Fall through. */
267		}
268	}
269
270	return -EIO;
271}
272
273static int manage_channel(struct fw_card *card, int irm_id, int generation,
274		u32 channels_mask, u64 offset, bool allocate)
275{
276	__be32 bit, all, old;
277	__be32 data[2];
278	int channel, ret = -EIO, retry = 5;
279
280	old = all = allocate ? cpu_to_be32(~0) : 0;
281
282	for (channel = 0; channel < 32; channel++) {
283		if (!(channels_mask & 1 << channel))
284			continue;
285
286		ret = -EBUSY;
287
288		bit = cpu_to_be32(1 << (31 - channel));
289		if ((old & bit) != (all & bit))
290			continue;
291
292		data[0] = old;
293		data[1] = old ^ bit;
294		switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
295					   irm_id, generation, SCODE_100,
296					   offset, data, 8)) {
297		case RCODE_GENERATION:
298			/* A generation change frees all channels. */
299			return allocate ? -EAGAIN : channel;
300
301		case RCODE_COMPLETE:
302			if (data[0] == old)
303				return channel;
304
305			old = data[0];
306
307			/* Is the IRM 1394a-2000 compliant? */
308			if ((data[0] & bit) == (data[1] & bit))
309				continue;
310
311			/* 1394-1995 IRM, fall through to retry. */
312		default:
313			if (retry) {
314				retry--;
315				channel--;
316			} else {
317				ret = -EIO;
318			}
319		}
320	}
321
322	return ret;
323}
324
325static void deallocate_channel(struct fw_card *card, int irm_id,
326			       int generation, int channel)
327{
328	u32 mask;
329	u64 offset;
330
331	mask = channel < 32 ? 1 << channel : 1 << (channel - 32);
332	offset = channel < 32 ? CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI :
333				CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO;
334
335	manage_channel(card, irm_id, generation, mask, offset, false);
336}
337
338/**
339 * fw_iso_resource_manage() - Allocate or deallocate a channel and/or bandwidth
340 *
341 * In parameters: card, generation, channels_mask, bandwidth, allocate
342 * Out parameters: channel, bandwidth
343 * This function blocks (sleeps) during communication with the IRM.
344 *
345 * Allocates or deallocates at most one channel out of channels_mask.
346 * channels_mask is a bitfield with MSB for channel 63 and LSB for channel 0.
347 * (Note, the IRM's CHANNELS_AVAILABLE is a big-endian bitfield with MSB for
348 * channel 0 and LSB for channel 63.)
349 * Allocates or deallocates as many bandwidth allocation units as specified.
350 *
351 * Returns channel < 0 if no channel was allocated or deallocated.
352 * Returns bandwidth = 0 if no bandwidth was allocated or deallocated.
353 *
354 * If generation is stale, deallocations succeed but allocations fail with
355 * channel = -EAGAIN.
356 *
357 * If channel allocation fails, no bandwidth will be allocated either.
358 * If bandwidth allocation fails, no channel will be allocated either.
359 * But deallocations of channel and bandwidth are tried independently
360 * of each other's success.
361 */
362void fw_iso_resource_manage(struct fw_card *card, int generation,
363			    u64 channels_mask, int *channel, int *bandwidth,
364			    bool allocate)
365{
366	u32 channels_hi = channels_mask;	/* channels 31...0 */
367	u32 channels_lo = channels_mask >> 32;	/* channels 63...32 */
368	int irm_id, ret, c = -EINVAL;
369
370	spin_lock_irq(&card->lock);
371	irm_id = card->irm_node->node_id;
372	spin_unlock_irq(&card->lock);
373
374	if (channels_hi)
375		c = manage_channel(card, irm_id, generation, channels_hi,
376				CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI,
377				allocate);
378	if (channels_lo && c < 0) {
379		c = manage_channel(card, irm_id, generation, channels_lo,
380				CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO,
381				allocate);
382		if (c >= 0)
383			c += 32;
384	}
385	*channel = c;
386
387	if (allocate && channels_mask != 0 && c < 0)
388		*bandwidth = 0;
389
390	if (*bandwidth == 0)
391		return;
392
393	ret = manage_bandwidth(card, irm_id, generation, *bandwidth, allocate);
394	if (ret < 0)
395		*bandwidth = 0;
396
397	if (allocate && ret < 0) {
398		if (c >= 0)
399			deallocate_channel(card, irm_id, generation, c);
400		*channel = ret;
401	}
402}
403EXPORT_SYMBOL(fw_iso_resource_manage);
404