arm: tegra: fb: Apply new mode even if its current
[linux-2.6.git] / drivers / firewire / core-iso.c
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
41 int 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 }
84 EXPORT_SYMBOL(fw_iso_buffer_init);
85
86 int 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
103 void 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 }
119 EXPORT_SYMBOL(fw_iso_buffer_destroy);
120
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)
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
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)
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 }
159 EXPORT_SYMBOL(fw_iso_context_create);
160
161 void fw_iso_context_destroy(struct fw_iso_context *ctx)
162 {
163         ctx->card->driver->free_iso_context(ctx);
164 }
165 EXPORT_SYMBOL(fw_iso_context_destroy);
166
167 int 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 }
172 EXPORT_SYMBOL(fw_iso_context_start);
173
174 int 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
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)
183 {
184         return ctx->card->driver->queue_iso(ctx, packet, buffer, payload);
185 }
186 EXPORT_SYMBOL(fw_iso_context_queue);
187
188 void fw_iso_context_queue_flush(struct fw_iso_context *ctx)
189 {
190         ctx->card->driver->flush_queue_iso(ctx);
191 }
192 EXPORT_SYMBOL(fw_iso_context_queue_flush);
193
194 int fw_iso_context_stop(struct fw_iso_context *ctx)
195 {
196         return ctx->card->driver->stop_iso(ctx);
197 }
198 EXPORT_SYMBOL(fw_iso_context_stop);
199
200 /*
201  * Isochronous bus resource management (channels, bandwidth), client side
202  */
203
204 static 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
242 static 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
294 static 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  */
331 void 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 }
372 EXPORT_SYMBOL(fw_iso_resource_manage);