root/drivers/firewire/core-iso.c

DEFINITIONS

1. fw_iso_buffer_alloc
2. fw_iso_buffer_map_dma
3. fw_iso_buffer_init
4. fw_iso_buffer_map_vma
5. fw_iso_buffer_destroy
6. fw_iso_buffer_lookup
7. fw_iso_context_create
8. fw_iso_context_destroy
9. fw_iso_context_start
10. fw_iso_context_set_channels
11. fw_iso_context_queue
12. fw_iso_context_queue_flush
13. fw_iso_context_flush_completions
14. fw_iso_context_stop
15. manage_bandwidth
16. manage_channel
17. deallocate_channel
18. fw_iso_resource_manage

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Isochronous I/O functionality:
   4  *   - Isochronous DMA context management
   5  *   - Isochronous bus resource management (channels, bandwidth), client side
   6  *
   7  * Copyright (C) 2006 Kristian Hoegsberg <krh@bitplanet.net>
   8  */
   9 
  10 #include <linux/dma-mapping.h>
  11 #include <linux/errno.h>
  12 #include <linux/firewire.h>
  13 #include <linux/firewire-constants.h>
  14 #include <linux/kernel.h>
  15 #include <linux/mm.h>
  16 #include <linux/slab.h>
  17 #include <linux/spinlock.h>
  18 #include <linux/vmalloc.h>
  19 #include <linux/export.h>
  20 
  21 #include <asm/byteorder.h>
  22 
  23 #include "core.h"
  24 
  25 /*
  26  * Isochronous DMA context management
  27  */
  28 
  29 int fw_iso_buffer_alloc(struct fw_iso_buffer *buffer, int page_count)
  30 {
  31         int i;
  32 
  33         buffer->page_count = 0;
  34         buffer->page_count_mapped = 0;
  35         buffer->pages = kmalloc_array(page_count, sizeof(buffer->pages[0]),
  36                                       GFP_KERNEL);
  37         if (buffer->pages == NULL)
  38                 return -ENOMEM;
  39 
  40         for (i = 0; i < page_count; i++) {
  41                 buffer->pages[i] = alloc_page(GFP_KERNEL | GFP_DMA32 | __GFP_ZERO);
  42                 if (buffer->pages[i] == NULL)
  43                         break;
  44         }
  45         buffer->page_count = i;
  46         if (i < page_count) {
  47                 fw_iso_buffer_destroy(buffer, NULL);
  48                 return -ENOMEM;
  49         }
  50 
  51         return 0;
  52 }
  53 
  54 int fw_iso_buffer_map_dma(struct fw_iso_buffer *buffer, struct fw_card *card,
  55                           enum dma_data_direction direction)
  56 {
  57         dma_addr_t address;
  58         int i;
  59 
  60         buffer->direction = direction;
  61 
  62         for (i = 0; i < buffer->page_count; i++) {
  63                 address = dma_map_page(card->device, buffer->pages[i],
  64                                        0, PAGE_SIZE, direction);
  65                 if (dma_mapping_error(card->device, address))
  66                         break;
  67 
  68                 set_page_private(buffer->pages[i], address);
  69         }
  70         buffer->page_count_mapped = i;
  71         if (i < buffer->page_count)
  72                 return -ENOMEM;
  73 
  74         return 0;
  75 }
  76 
  77 int fw_iso_buffer_init(struct fw_iso_buffer *buffer, struct fw_card *card,
  78                        int page_count, enum dma_data_direction direction)
  79 {
  80         int ret;
  81 
  82         ret = fw_iso_buffer_alloc(buffer, page_count);
  83         if (ret < 0)
  84                 return ret;
  85 
  86         ret = fw_iso_buffer_map_dma(buffer, card, direction);
  87         if (ret < 0)
  88                 fw_iso_buffer_destroy(buffer, card);
  89 
  90         return ret;
  91 }
  92 EXPORT_SYMBOL(fw_iso_buffer_init);
  93 
  94 int fw_iso_buffer_map_vma(struct fw_iso_buffer *buffer,
  95                           struct vm_area_struct *vma)
  96 {
  97         return vm_map_pages_zero(vma, buffer->pages,
  98                                         buffer->page_count);
  99 }
 100 
 101 void fw_iso_buffer_destroy(struct fw_iso_buffer *buffer,
 102                            struct fw_card *card)
 103 {
 104         int i;
 105         dma_addr_t address;
 106 
 107         for (i = 0; i < buffer->page_count_mapped; i++) {
 108                 address = page_private(buffer->pages[i]);
 109                 dma_unmap_page(card->device, address,
 110                                PAGE_SIZE, buffer->direction);
 111         }
 112         for (i = 0; i < buffer->page_count; i++)
 113                 __free_page(buffer->pages[i]);
 114 
 115         kfree(buffer->pages);
 116         buffer->pages = NULL;
 117         buffer->page_count = 0;
 118         buffer->page_count_mapped = 0;
 119 }
 120 EXPORT_SYMBOL(fw_iso_buffer_destroy);
 121 
 122 /* Convert DMA address to offset into virtually contiguous buffer. */
 123 size_t fw_iso_buffer_lookup(struct fw_iso_buffer *buffer, dma_addr_t completed)
 124 {
 125         size_t i;
 126         dma_addr_t address;
 127         ssize_t offset;
 128 
 129         for (i = 0; i < buffer->page_count; i++) {
 130                 address = page_private(buffer->pages[i]);
 131                 offset = (ssize_t)completed - (ssize_t)address;
 132                 if (offset > 0 && offset <= PAGE_SIZE)
 133                         return (i << PAGE_SHIFT) + offset;
 134         }
 135 
 136         return 0;
 137 }
 138 
 139 struct fw_iso_context *fw_iso_context_create(struct fw_card *card,
 140                 int type, int channel, int speed, size_t header_size,
 141                 fw_iso_callback_t callback, void *callback_data)
 142 {
 143         struct fw_iso_context *ctx;
 144 
 145         ctx = card->driver->allocate_iso_context(card,
 146                                                  type, channel, header_size);
 147         if (IS_ERR(ctx))
 148                 return ctx;
 149 
 150         ctx->card = card;
 151         ctx->type = type;
 152         ctx->channel = channel;
 153         ctx->speed = speed;
 154         ctx->header_size = header_size;
 155         ctx->callback.sc = callback;
 156         ctx->callback_data = callback_data;
 157 
 158         return ctx;
 159 }
 160 EXPORT_SYMBOL(fw_iso_context_create);
 161 
 162 void fw_iso_context_destroy(struct fw_iso_context *ctx)
 163 {
 164         ctx->card->driver->free_iso_context(ctx);
 165 }
 166 EXPORT_SYMBOL(fw_iso_context_destroy);
 167 
 168 int fw_iso_context_start(struct fw_iso_context *ctx,
 169                          int cycle, int sync, int tags)
 170 {
 171         return ctx->card->driver->start_iso(ctx, cycle, sync, tags);
 172 }
 173 EXPORT_SYMBOL(fw_iso_context_start);
 174 
 175 int fw_iso_context_set_channels(struct fw_iso_context *ctx, u64 *channels)
 176 {
 177         return ctx->card->driver->set_iso_channels(ctx, channels);
 178 }
 179 
 180 int fw_iso_context_queue(struct fw_iso_context *ctx,
 181                          struct fw_iso_packet *packet,
 182                          struct fw_iso_buffer *buffer,
 183                          unsigned long payload)
 184 {
 185         return ctx->card->driver->queue_iso(ctx, packet, buffer, payload);
 186 }
 187 EXPORT_SYMBOL(fw_iso_context_queue);
 188 
 189 void fw_iso_context_queue_flush(struct fw_iso_context *ctx)
 190 {
 191         ctx->card->driver->flush_queue_iso(ctx);
 192 }
 193 EXPORT_SYMBOL(fw_iso_context_queue_flush);
 194 
 195 int fw_iso_context_flush_completions(struct fw_iso_context *ctx)
 196 {
 197         return ctx->card->driver->flush_iso_completions(ctx);
 198 }
 199 EXPORT_SYMBOL(fw_iso_context_flush_completions);
 200 
 201 int fw_iso_context_stop(struct fw_iso_context *ctx)
 202 {
 203         return ctx->card->driver->stop_iso(ctx);
 204 }
 205 EXPORT_SYMBOL(fw_iso_context_stop);
 206 
 207 /*
 208  * Isochronous bus resource management (channels, bandwidth), client side
 209  */
 210 
 211 static int manage_bandwidth(struct fw_card *card, int irm_id, int generation,
 212                             int bandwidth, bool allocate)
 213 {
 214         int try, new, old = allocate ? BANDWIDTH_AVAILABLE_INITIAL : 0;
 215         __be32 data[2];
 216 
 217         /*
 218          * On a 1394a IRM with low contention, try < 1 is enough.
 219          * On a 1394-1995 IRM, we need at least try < 2.
 220          * Let's just do try < 5.
 221          */
 222         for (try = 0; try < 5; try++) {
 223                 new = allocate ? old - bandwidth : old + bandwidth;
 224                 if (new < 0 || new > BANDWIDTH_AVAILABLE_INITIAL)
 225                         return -EBUSY;
 226 
 227                 data[0] = cpu_to_be32(old);
 228                 data[1] = cpu_to_be32(new);
 229                 switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
 230                                 irm_id, generation, SCODE_100,
 231                                 CSR_REGISTER_BASE + CSR_BANDWIDTH_AVAILABLE,
 232                                 data, 8)) {
 233                 case RCODE_GENERATION:
 234                         /* A generation change frees all bandwidth. */
 235                         return allocate ? -EAGAIN : bandwidth;
 236 
 237                 case RCODE_COMPLETE:
 238                         if (be32_to_cpup(data) == old)
 239                                 return bandwidth;
 240 
 241                         old = be32_to_cpup(data);
 242                         /* Fall through. */
 243                 }
 244         }
 245 
 246         return -EIO;
 247 }
 248 
 249 static int manage_channel(struct fw_card *card, int irm_id, int generation,
 250                 u32 channels_mask, u64 offset, bool allocate)
 251 {
 252         __be32 bit, all, old;
 253         __be32 data[2];
 254         int channel, ret = -EIO, retry = 5;
 255 
 256         old = all = allocate ? cpu_to_be32(~0) : 0;
 257 
 258         for (channel = 0; channel < 32; channel++) {
 259                 if (!(channels_mask & 1 << channel))
 260                         continue;
 261 
 262                 ret = -EBUSY;
 263 
 264                 bit = cpu_to_be32(1 << (31 - channel));
 265                 if ((old & bit) != (all & bit))
 266                         continue;
 267 
 268                 data[0] = old;
 269                 data[1] = old ^ bit;
 270                 switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
 271                                            irm_id, generation, SCODE_100,
 272                                            offset, data, 8)) {
 273                 case RCODE_GENERATION:
 274                         /* A generation change frees all channels. */
 275                         return allocate ? -EAGAIN : channel;
 276 
 277                 case RCODE_COMPLETE:
 278                         if (data[0] == old)
 279                                 return channel;
 280 
 281                         old = data[0];
 282 
 283                         /* Is the IRM 1394a-2000 compliant? */
 284                         if ((data[0] & bit) == (data[1] & bit))
 285                                 continue;
 286 
 287                         /* fall through - It's a 1394-1995 IRM, retry. */
 288                 default:
 289                         if (retry) {
 290                                 retry--;
 291                                 channel--;
 292                         } else {
 293                                 ret = -EIO;
 294                         }
 295                 }
 296         }
 297 
 298         return ret;
 299 }
 300 
 301 static void deallocate_channel(struct fw_card *card, int irm_id,
 302                                int generation, int channel)
 303 {
 304         u32 mask;
 305         u64 offset;
 306 
 307         mask = channel < 32 ? 1 << channel : 1 << (channel - 32);
 308         offset = channel < 32 ? CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI :
 309                                 CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO;
 310 
 311         manage_channel(card, irm_id, generation, mask, offset, false);
 312 }
 313 
 314 /**
 315  * fw_iso_resource_manage() - Allocate or deallocate a channel and/or bandwidth
 316  * @card: card interface for this action
 317  * @generation: bus generation
 318  * @channels_mask: bitmask for channel allocation
 319  * @channel: pointer for returning channel allocation result
 320  * @bandwidth: pointer for returning bandwidth allocation result
 321  * @allocate: whether to allocate (true) or deallocate (false)
 322  *
 323  * In parameters: card, generation, channels_mask, bandwidth, allocate
 324  * Out parameters: channel, bandwidth
 325  *
 326  * This function blocks (sleeps) during communication with the IRM.
 327  *
 328  * Allocates or deallocates at most one channel out of channels_mask.
 329  * channels_mask is a bitfield with MSB for channel 63 and LSB for channel 0.
 330  * (Note, the IRM's CHANNELS_AVAILABLE is a big-endian bitfield with MSB for
 331  * channel 0 and LSB for channel 63.)
 332  * Allocates or deallocates as many bandwidth allocation units as specified.
 333  *
 334  * Returns channel < 0 if no channel was allocated or deallocated.
 335  * Returns bandwidth = 0 if no bandwidth was allocated or deallocated.
 336  *
 337  * If generation is stale, deallocations succeed but allocations fail with
 338  * channel = -EAGAIN.
 339  *
 340  * If channel allocation fails, no bandwidth will be allocated either.
 341  * If bandwidth allocation fails, no channel will be allocated either.
 342  * But deallocations of channel and bandwidth are tried independently
 343  * of each other's success.
 344  */
 345 void fw_iso_resource_manage(struct fw_card *card, int generation,
 346                             u64 channels_mask, int *channel, int *bandwidth,
 347                             bool allocate)
 348 {
 349         u32 channels_hi = channels_mask;        /* channels 31...0 */
 350         u32 channels_lo = channels_mask >> 32;  /* channels 63...32 */
 351         int irm_id, ret, c = -EINVAL;
 352 
 353         spin_lock_irq(&card->lock);
 354         irm_id = card->irm_node->node_id;
 355         spin_unlock_irq(&card->lock);
 356 
 357         if (channels_hi)
 358                 c = manage_channel(card, irm_id, generation, channels_hi,
 359                                 CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI,
 360                                 allocate);
 361         if (channels_lo && c < 0) {
 362                 c = manage_channel(card, irm_id, generation, channels_lo,
 363                                 CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO,
 364                                 allocate);
 365                 if (c >= 0)
 366                         c += 32;
 367         }
 368         *channel = c;
 369 
 370         if (allocate && channels_mask != 0 && c < 0)
 371                 *bandwidth = 0;
 372 
 373         if (*bandwidth == 0)
 374                 return;
 375 
 376         ret = manage_bandwidth(card, irm_id, generation, *bandwidth, allocate);
 377         if (ret < 0)
 378                 *bandwidth = 0;
 379 
 380         if (allocate && ret < 0) {
 381                 if (c >= 0)
 382                         deallocate_channel(card, irm_id, generation, c);
 383                 *channel = ret;
 384         }
 385 }
 386 EXPORT_SYMBOL(fw_iso_resource_manage);