drivers/firewire/core-iso.c

   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 void fw_iso_buffer_destroy(struct fw_iso_buffer *buffer,
  95                            struct fw_card *card)
  96 {
  97         int i;
  98         dma_addr_t address;
  99
 100         for (i = 0; i < buffer->page_count_mapped; i++) {
 101                 address = page_private(buffer->pages[i]);
 102                 dma_unmap_page(card->device, address,
 103                                PAGE_SIZE, buffer->direction);
 104         }
 105         for (i = 0; i < buffer->page_count; i++)
 106                 __free_page(buffer->pages[i]);
 107
 108         kfree(buffer->pages);
 109         buffer->pages = NULL;
 110         buffer->page_count = 0;
 111         buffer->page_count_mapped = 0;
 112 }
 113 EXPORT_SYMBOL(fw_iso_buffer_destroy);
 114
 115 /* Convert DMA address to offset into virtually contiguous buffer. */
 116 size_t fw_iso_buffer_lookup(struct fw_iso_buffer *buffer, dma_addr_t completed)
 117 {
 118         size_t i;
 119         dma_addr_t address;
 120         ssize_t offset;
 121
 122         for (i = 0; i < buffer->page_count; i++) {
 123                 address = page_private(buffer->pages[i]);
 124                 offset = (ssize_t)completed - (ssize_t)address;
 125                 if (offset > 0 && offset <= PAGE_SIZE)
 126                         return (i << PAGE_SHIFT) + offset;
 127         }
 128
 129         return 0;
 130 }
 131
 132 struct fw_iso_context *fw_iso_context_create(struct fw_card *card,
 133                 int type, int channel, int speed, size_t header_size,
 134                 fw_iso_callback_t callback, void *callback_data)
 135 {
 136         struct fw_iso_context *ctx;
 137
 138         ctx = card->driver->allocate_iso_context(card,
 139                                                  type, channel, header_size);
 140         if (IS_ERR(ctx))
 141                 return ctx;
 142
 143         ctx->card = card;
 144         ctx->type = type;
 145         ctx->channel = channel;
 146         ctx->speed = speed;
 147         ctx->header_size = header_size;
 148         ctx->callback.sc = callback;
 149         ctx->callback_data = callback_data;
 150
 151         return ctx;
 152 }
 153 EXPORT_SYMBOL(fw_iso_context_create);
 154
 155 void fw_iso_context_destroy(struct fw_iso_context *ctx)
 156 {
 157         ctx->card->driver->free_iso_context(ctx);
 158 }
 159 EXPORT_SYMBOL(fw_iso_context_destroy);
 160
 161 int fw_iso_context_start(struct fw_iso_context *ctx,
 162                          int cycle, int sync, int tags)
 163 {
 164         return ctx->card->driver->start_iso(ctx, cycle, sync, tags);
 165 }
 166 EXPORT_SYMBOL(fw_iso_context_start);
 167
 168 int fw_iso_context_set_channels(struct fw_iso_context *ctx, u64 *channels)
 169 {
 170         return ctx->card->driver->set_iso_channels(ctx, channels);
 171 }
 172
 173 int fw_iso_context_queue(struct fw_iso_context *ctx,
 174                          struct fw_iso_packet *packet,
 175                          struct fw_iso_buffer *buffer,
 176                          unsigned long payload)
 177 {
 178         return ctx->card->driver->queue_iso(ctx, packet, buffer, payload);
 179 }
 180 EXPORT_SYMBOL(fw_iso_context_queue);
 181
 182 void fw_iso_context_queue_flush(struct fw_iso_context *ctx)
 183 {
 184         ctx->card->driver->flush_queue_iso(ctx);
 185 }
 186 EXPORT_SYMBOL(fw_iso_context_queue_flush);
 187
 188 int fw_iso_context_flush_completions(struct fw_iso_context *ctx)
 189 {
 190         return ctx->card->driver->flush_iso_completions(ctx);
 191 }
 192 EXPORT_SYMBOL(fw_iso_context_flush_completions);
 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                         fallthrough;    /* It's a 1394-1995 IRM, 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  * @card: card interface for this action
 310  * @generation: bus generation
 311  * @channels_mask: bitmask for channel allocation
 312  * @channel: pointer for returning channel allocation result
 313  * @bandwidth: pointer for returning bandwidth allocation result
 314  * @allocate: whether to allocate (true) or deallocate (false)
 315  *
 316  * In parameters: card, generation, channels_mask, bandwidth, allocate
 317  * Out parameters: channel, bandwidth
 318  *
 319  * This function blocks (sleeps) during communication with the IRM.
 320  *
 321  * Allocates or deallocates at most one channel out of channels_mask.
 322  * channels_mask is a bitfield with MSB for channel 63 and LSB for channel 0.
 323  * (Note, the IRM's CHANNELS_AVAILABLE is a big-endian bitfield with MSB for
 324  * channel 0 and LSB for channel 63.)
 325  * Allocates or deallocates as many bandwidth allocation units as specified.
 326  *
 327  * Returns channel < 0 if no channel was allocated or deallocated.
 328  * Returns bandwidth = 0 if no bandwidth was allocated or deallocated.
 329  *
 330  * If generation is stale, deallocations succeed but allocations fail with
 331  * channel = -EAGAIN.
 332  *
 333  * If channel allocation fails, no bandwidth will be allocated either.
 334  * If bandwidth allocation fails, no channel will be allocated either.
 335  * But deallocations of channel and bandwidth are tried independently
 336  * of each other's success.
 337  */
 338 void fw_iso_resource_manage(struct fw_card *card, int generation,
 339                             u64 channels_mask, int *channel, int *bandwidth,
 340                             bool allocate)
 341 {
 342         u32 channels_hi = channels_mask;        /* channels 31...0 */
 343         u32 channels_lo = channels_mask >> 32;  /* channels 63...32 */
 344         int irm_id, ret, c = -EINVAL;
 345
 346         spin_lock_irq(&card->lock);
 347         irm_id = card->irm_node->node_id;
 348         spin_unlock_irq(&card->lock);
 349
 350         if (channels_hi)
 351                 c = manage_channel(card, irm_id, generation, channels_hi,
 352                                 CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI,
 353                                 allocate);
 354         if (channels_lo && c < 0) {
 355                 c = manage_channel(card, irm_id, generation, channels_lo,
 356                                 CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO,
 357                                 allocate);
 358                 if (c >= 0)
 359                         c += 32;
 360         }
 361         *channel = c;
 362
 363         if (allocate && channels_mask != 0 && c < 0)
 364                 *bandwidth = 0;
 365
 366         if (*bandwidth == 0)
 367                 return;
 368
 369         ret = manage_bandwidth(card, irm_id, generation, *bandwidth, allocate);
 370         if (ret < 0)
 371                 *bandwidth = 0;
 372
 373         if (allocate && ret < 0) {
 374                 if (c >= 0)
 375                         deallocate_channel(card, irm_id, generation, c);
 376                 *channel = ret;
 377         }
 378 }
 379 EXPORT_SYMBOL(fw_iso_resource_manage);