Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[linux-btrfs-devel.git] / drivers / firewire / core-iso.c
blob57c3973093ad13ab49355f6af6e9c38f05a5bcae
1 /*
2 * Isochronous I/O functionality:
3 * - Isochronous DMA context management
4 * - Isochronous bus resource management (channels, bandwidth), client side
6 * Copyright (C) 2006 Kristian Hoegsberg <krh@bitplanet.net>
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.
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.
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.
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>
33 #include <asm/byteorder.h>
35 #include "core.h"
38 * Isochronous DMA context management
41 int fw_iso_buffer_init(struct fw_iso_buffer *buffer, struct fw_card *card,
42 int page_count, enum dma_data_direction direction)
44 int i, j;
45 dma_addr_t address;
47 buffer->page_count = page_count;
48 buffer->direction = direction;
50 buffer->pages = kmalloc(page_count * sizeof(buffer->pages[0]),
51 GFP_KERNEL);
52 if (buffer->pages == NULL)
53 goto out;
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;
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;
66 set_page_private(buffer->pages[i], address);
69 return 0;
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]);
78 kfree(buffer->pages);
79 out:
80 buffer->pages = NULL;
82 return -ENOMEM;
84 EXPORT_SYMBOL(fw_iso_buffer_init);
86 int fw_iso_buffer_map(struct fw_iso_buffer *buffer, struct vm_area_struct *vma)
88 unsigned long uaddr;
89 int i, err;
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;
97 uaddr += PAGE_SIZE;
100 return 0;
103 void fw_iso_buffer_destroy(struct fw_iso_buffer *buffer,
104 struct fw_card *card)
106 int i;
107 dma_addr_t address;
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]);
116 kfree(buffer->pages);
117 buffer->pages = NULL;
119 EXPORT_SYMBOL(fw_iso_buffer_destroy);
121 /* Convert DMA address to offset into virtually contiguous buffer. */
122 size_t fw_iso_buffer_lookup(struct fw_iso_buffer *buffer, dma_addr_t completed)
124 int i;
125 dma_addr_t address;
126 ssize_t offset;
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;
135 return 0;
138 struct 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)
142 struct fw_iso_context *ctx;
144 ctx = card->driver->allocate_iso_context(card,
145 type, channel, header_size);
146 if (IS_ERR(ctx))
147 return ctx;
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;
157 return ctx;
159 EXPORT_SYMBOL(fw_iso_context_create);
161 void fw_iso_context_destroy(struct fw_iso_context *ctx)
163 ctx->card->driver->free_iso_context(ctx);
165 EXPORT_SYMBOL(fw_iso_context_destroy);
167 int fw_iso_context_start(struct fw_iso_context *ctx,
168 int cycle, int sync, int tags)
170 return ctx->card->driver->start_iso(ctx, cycle, sync, tags);
172 EXPORT_SYMBOL(fw_iso_context_start);
174 int fw_iso_context_set_channels(struct fw_iso_context *ctx, u64 *channels)
176 return ctx->card->driver->set_iso_channels(ctx, channels);
179 int 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)
184 return ctx->card->driver->queue_iso(ctx, packet, buffer, payload);
186 EXPORT_SYMBOL(fw_iso_context_queue);
188 void fw_iso_context_queue_flush(struct fw_iso_context *ctx)
190 ctx->card->driver->flush_queue_iso(ctx);
192 EXPORT_SYMBOL(fw_iso_context_queue_flush);
194 int fw_iso_context_stop(struct fw_iso_context *ctx)
196 return ctx->card->driver->stop_iso(ctx);
198 EXPORT_SYMBOL(fw_iso_context_stop);
201 * Isochronous bus resource management (channels, bandwidth), client side
204 static int manage_bandwidth(struct fw_card *card, int irm_id, int generation,
205 int bandwidth, bool allocate)
207 int try, new, old = allocate ? BANDWIDTH_AVAILABLE_INITIAL : 0;
208 __be32 data[2];
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.
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;
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;
230 case RCODE_COMPLETE:
231 if (be32_to_cpup(data) == old)
232 return bandwidth;
234 old = be32_to_cpup(data);
235 /* Fall through. */
239 return -EIO;
242 static int manage_channel(struct fw_card *card, int irm_id, int generation,
243 u32 channels_mask, u64 offset, bool allocate)
245 __be32 bit, all, old;
246 __be32 data[2];
247 int channel, ret = -EIO, retry = 5;
249 old = all = allocate ? cpu_to_be32(~0) : 0;
251 for (channel = 0; channel < 32; channel++) {
252 if (!(channels_mask & 1 << channel))
253 continue;
255 ret = -EBUSY;
257 bit = cpu_to_be32(1 << (31 - channel));
258 if ((old & bit) != (all & bit))
259 continue;
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;
270 case RCODE_COMPLETE:
271 if (data[0] == old)
272 return channel;
274 old = data[0];
276 /* Is the IRM 1394a-2000 compliant? */
277 if ((data[0] & bit) == (data[1] & bit))
278 continue;
280 /* 1394-1995 IRM, fall through to retry. */
281 default:
282 if (retry) {
283 retry--;
284 channel--;
285 } else {
286 ret = -EIO;
291 return ret;
294 static void deallocate_channel(struct fw_card *card, int irm_id,
295 int generation, int channel)
297 u32 mask;
298 u64 offset;
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;
304 manage_channel(card, irm_id, generation, mask, offset, false);
308 * fw_iso_resource_manage() - Allocate or deallocate a channel and/or bandwidth
310 * In parameters: card, generation, channels_mask, bandwidth, allocate
311 * Out parameters: channel, bandwidth
312 * This function blocks (sleeps) during communication with the IRM.
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.
320 * Returns channel < 0 if no channel was allocated or deallocated.
321 * Returns bandwidth = 0 if no bandwidth was allocated or deallocated.
323 * If generation is stale, deallocations succeed but allocations fail with
324 * channel = -EAGAIN.
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.
331 void fw_iso_resource_manage(struct fw_card *card, int generation,
332 u64 channels_mask, int *channel, int *bandwidth,
333 bool allocate)
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;
339 spin_lock_irq(&card->lock);
340 irm_id = card->irm_node->node_id;
341 spin_unlock_irq(&card->lock);
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;
354 *channel = c;
356 if (allocate && channels_mask != 0 && c < 0)
357 *bandwidth = 0;
359 if (*bandwidth == 0)
360 return;
362 ret = manage_bandwidth(card, irm_id, generation, *bandwidth, allocate);
363 if (ret < 0)
364 *bandwidth = 0;
366 if (allocate && ret < 0) {
367 if (c >= 0)
368 deallocate_channel(card, irm_id, generation, c);
369 *channel = ret;
372 EXPORT_SYMBOL(fw_iso_resource_manage);