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v3.1
  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
 33#include <asm/byteorder.h>
 34
 35#include "core.h"
 36
 37/*
 38 * Isochronous DMA context management
 39 */
 40
 41int fw_iso_buffer_init(struct fw_iso_buffer *buffer, struct fw_card *card,
 42		       int page_count, enum dma_data_direction direction)
 43{
 44	int i, j;
 45	dma_addr_t address;
 46
 47	buffer->page_count = page_count;
 48	buffer->direction = direction;
 49
 
 
 50	buffer->pages = kmalloc(page_count * sizeof(buffer->pages[0]),
 51				GFP_KERNEL);
 52	if (buffer->pages == NULL)
 53		goto out;
 54
 55	for (i = 0; i < buffer->page_count; i++) {
 56		buffer->pages[i] = alloc_page(GFP_KERNEL | GFP_DMA32 | __GFP_ZERO);
 57		if (buffer->pages[i] == NULL)
 58			goto out_pages;
 
 
 
 
 
 
 59
 
 
 
 
 
 
 
 
 
 
 
 
 60		address = dma_map_page(card->device, buffer->pages[i],
 61				       0, PAGE_SIZE, direction);
 62		if (dma_mapping_error(card->device, address)) {
 63			__free_page(buffer->pages[i]);
 64			goto out_pages;
 65		}
 66		set_page_private(buffer->pages[i], address);
 67	}
 
 
 
 68
 69	return 0;
 
 70
 71 out_pages:
 72	for (j = 0; j < i; j++) {
 73		address = page_private(buffer->pages[j]);
 74		dma_unmap_page(card->device, address,
 75			       PAGE_SIZE, direction);
 76		__free_page(buffer->pages[j]);
 77	}
 78	kfree(buffer->pages);
 79 out:
 80	buffer->pages = NULL;
 81
 82	return -ENOMEM;
 
 
 
 
 
 
 
 
 83}
 84EXPORT_SYMBOL(fw_iso_buffer_init);
 85
 86int fw_iso_buffer_map(struct fw_iso_buffer *buffer, struct vm_area_struct *vma)
 
 87{
 88	unsigned long uaddr;
 89	int i, err;
 90
 91	uaddr = vma->vm_start;
 92	for (i = 0; i < buffer->page_count; i++) {
 93		err = vm_insert_page(vma, uaddr, buffer->pages[i]);
 94		if (err)
 95			return err;
 96
 97		uaddr += PAGE_SIZE;
 98	}
 99
100	return 0;
101}
102
103void fw_iso_buffer_destroy(struct fw_iso_buffer *buffer,
104			   struct fw_card *card)
105{
106	int i;
107	dma_addr_t address;
108
109	for (i = 0; i < buffer->page_count; i++) {
110		address = page_private(buffer->pages[i]);
111		dma_unmap_page(card->device, address,
112			       PAGE_SIZE, buffer->direction);
113		__free_page(buffer->pages[i]);
114	}
 
 
115
116	kfree(buffer->pages);
117	buffer->pages = NULL;
 
 
118}
119EXPORT_SYMBOL(fw_iso_buffer_destroy);
120
121/* Convert DMA address to offset into virtually contiguous buffer. */
122size_t fw_iso_buffer_lookup(struct fw_iso_buffer *buffer, dma_addr_t completed)
123{
124	int i;
125	dma_addr_t address;
126	ssize_t offset;
127
128	for (i = 0; i < buffer->page_count; i++) {
129		address = page_private(buffer->pages[i]);
130		offset = (ssize_t)completed - (ssize_t)address;
131		if (offset > 0 && offset <= PAGE_SIZE)
132			return (i << PAGE_SHIFT) + offset;
133	}
134
135	return 0;
136}
137
138struct fw_iso_context *fw_iso_context_create(struct fw_card *card,
139		int type, int channel, int speed, size_t header_size,
140		fw_iso_callback_t callback, void *callback_data)
141{
142	struct fw_iso_context *ctx;
143
144	ctx = card->driver->allocate_iso_context(card,
145						 type, channel, header_size);
146	if (IS_ERR(ctx))
147		return ctx;
148
149	ctx->card = card;
150	ctx->type = type;
151	ctx->channel = channel;
152	ctx->speed = speed;
153	ctx->header_size = header_size;
154	ctx->callback.sc = callback;
155	ctx->callback_data = callback_data;
156
157	return ctx;
158}
159EXPORT_SYMBOL(fw_iso_context_create);
160
161void fw_iso_context_destroy(struct fw_iso_context *ctx)
162{
163	ctx->card->driver->free_iso_context(ctx);
164}
165EXPORT_SYMBOL(fw_iso_context_destroy);
166
167int fw_iso_context_start(struct fw_iso_context *ctx,
168			 int cycle, int sync, int tags)
169{
170	return ctx->card->driver->start_iso(ctx, cycle, sync, tags);
171}
172EXPORT_SYMBOL(fw_iso_context_start);
173
174int fw_iso_context_set_channels(struct fw_iso_context *ctx, u64 *channels)
175{
176	return ctx->card->driver->set_iso_channels(ctx, channels);
177}
178
179int fw_iso_context_queue(struct fw_iso_context *ctx,
180			 struct fw_iso_packet *packet,
181			 struct fw_iso_buffer *buffer,
182			 unsigned long payload)
183{
184	return ctx->card->driver->queue_iso(ctx, packet, buffer, payload);
185}
186EXPORT_SYMBOL(fw_iso_context_queue);
187
188void fw_iso_context_queue_flush(struct fw_iso_context *ctx)
189{
190	ctx->card->driver->flush_queue_iso(ctx);
191}
192EXPORT_SYMBOL(fw_iso_context_queue_flush);
 
 
 
 
 
 
193
194int fw_iso_context_stop(struct fw_iso_context *ctx)
195{
196	return ctx->card->driver->stop_iso(ctx);
197}
198EXPORT_SYMBOL(fw_iso_context_stop);
199
200/*
201 * Isochronous bus resource management (channels, bandwidth), client side
202 */
203
204static int manage_bandwidth(struct fw_card *card, int irm_id, int generation,
205			    int bandwidth, bool allocate)
206{
207	int try, new, old = allocate ? BANDWIDTH_AVAILABLE_INITIAL : 0;
208	__be32 data[2];
209
210	/*
211	 * On a 1394a IRM with low contention, try < 1 is enough.
212	 * On a 1394-1995 IRM, we need at least try < 2.
213	 * Let's just do try < 5.
214	 */
215	for (try = 0; try < 5; try++) {
216		new = allocate ? old - bandwidth : old + bandwidth;
217		if (new < 0 || new > BANDWIDTH_AVAILABLE_INITIAL)
218			return -EBUSY;
219
220		data[0] = cpu_to_be32(old);
221		data[1] = cpu_to_be32(new);
222		switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
223				irm_id, generation, SCODE_100,
224				CSR_REGISTER_BASE + CSR_BANDWIDTH_AVAILABLE,
225				data, 8)) {
226		case RCODE_GENERATION:
227			/* A generation change frees all bandwidth. */
228			return allocate ? -EAGAIN : bandwidth;
229
230		case RCODE_COMPLETE:
231			if (be32_to_cpup(data) == old)
232				return bandwidth;
233
234			old = be32_to_cpup(data);
235			/* Fall through. */
236		}
237	}
238
239	return -EIO;
240}
241
242static int manage_channel(struct fw_card *card, int irm_id, int generation,
243		u32 channels_mask, u64 offset, bool allocate)
244{
245	__be32 bit, all, old;
246	__be32 data[2];
247	int channel, ret = -EIO, retry = 5;
248
249	old = all = allocate ? cpu_to_be32(~0) : 0;
250
251	for (channel = 0; channel < 32; channel++) {
252		if (!(channels_mask & 1 << channel))
253			continue;
254
255		ret = -EBUSY;
256
257		bit = cpu_to_be32(1 << (31 - channel));
258		if ((old & bit) != (all & bit))
259			continue;
260
261		data[0] = old;
262		data[1] = old ^ bit;
263		switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
264					   irm_id, generation, SCODE_100,
265					   offset, data, 8)) {
266		case RCODE_GENERATION:
267			/* A generation change frees all channels. */
268			return allocate ? -EAGAIN : channel;
269
270		case RCODE_COMPLETE:
271			if (data[0] == old)
272				return channel;
273
274			old = data[0];
275
276			/* Is the IRM 1394a-2000 compliant? */
277			if ((data[0] & bit) == (data[1] & bit))
278				continue;
279
280			/* 1394-1995 IRM, fall through to retry. */
281		default:
282			if (retry) {
283				retry--;
284				channel--;
285			} else {
286				ret = -EIO;
287			}
288		}
289	}
290
291	return ret;
292}
293
294static void deallocate_channel(struct fw_card *card, int irm_id,
295			       int generation, int channel)
296{
297	u32 mask;
298	u64 offset;
299
300	mask = channel < 32 ? 1 << channel : 1 << (channel - 32);
301	offset = channel < 32 ? CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI :
302				CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO;
303
304	manage_channel(card, irm_id, generation, mask, offset, false);
305}
306
307/**
308 * fw_iso_resource_manage() - Allocate or deallocate a channel and/or bandwidth
309 *
310 * In parameters: card, generation, channels_mask, bandwidth, allocate
311 * Out parameters: channel, bandwidth
312 * This function blocks (sleeps) during communication with the IRM.
313 *
314 * Allocates or deallocates at most one channel out of channels_mask.
315 * channels_mask is a bitfield with MSB for channel 63 and LSB for channel 0.
316 * (Note, the IRM's CHANNELS_AVAILABLE is a big-endian bitfield with MSB for
317 * channel 0 and LSB for channel 63.)
318 * Allocates or deallocates as many bandwidth allocation units as specified.
319 *
320 * Returns channel < 0 if no channel was allocated or deallocated.
321 * Returns bandwidth = 0 if no bandwidth was allocated or deallocated.
322 *
323 * If generation is stale, deallocations succeed but allocations fail with
324 * channel = -EAGAIN.
325 *
326 * If channel allocation fails, no bandwidth will be allocated either.
327 * If bandwidth allocation fails, no channel will be allocated either.
328 * But deallocations of channel and bandwidth are tried independently
329 * of each other's success.
330 */
331void fw_iso_resource_manage(struct fw_card *card, int generation,
332			    u64 channels_mask, int *channel, int *bandwidth,
333			    bool allocate)
334{
335	u32 channels_hi = channels_mask;	/* channels 31...0 */
336	u32 channels_lo = channels_mask >> 32;	/* channels 63...32 */
337	int irm_id, ret, c = -EINVAL;
338
339	spin_lock_irq(&card->lock);
340	irm_id = card->irm_node->node_id;
341	spin_unlock_irq(&card->lock);
342
343	if (channels_hi)
344		c = manage_channel(card, irm_id, generation, channels_hi,
345				CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI,
346				allocate);
347	if (channels_lo && c < 0) {
348		c = manage_channel(card, irm_id, generation, channels_lo,
349				CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO,
350				allocate);
351		if (c >= 0)
352			c += 32;
353	}
354	*channel = c;
355
356	if (allocate && channels_mask != 0 && c < 0)
357		*bandwidth = 0;
358
359	if (*bandwidth == 0)
360		return;
361
362	ret = manage_bandwidth(card, irm_id, generation, *bandwidth, allocate);
363	if (ret < 0)
364		*bandwidth = 0;
365
366	if (allocate && ret < 0) {
367		if (c >= 0)
368			deallocate_channel(card, irm_id, generation, c);
369		*channel = ret;
370	}
371}
372EXPORT_SYMBOL(fw_iso_resource_manage);
v4.6
  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);