sound/firewire/fcp.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Function Control Protocol (IEC 61883-1) helper functions
   4  *
   5  * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
   6  */
   7
   8 #include <linux/device.h>
   9 #include <linux/firewire.h>
  10 #include <linux/firewire-constants.h>
  11 #include <linux/list.h>
  12 #include <linux/module.h>
  13 #include <linux/slab.h>
  14 #include <linux/sched.h>
  15 #include <linux/spinlock.h>
  16 #include <linux/wait.h>
  17 #include <linux/delay.h>
  18 #include "fcp.h"
  19 #include "lib.h"
  20 #include "amdtp-stream.h"
  21
  22 #define CTS_AVC 0x00
  23
  24 #define ERROR_RETRIES   3
  25 #define ERROR_DELAY_MS  5
  26 #define FCP_TIMEOUT_MS  125
  27
  28 int avc_general_set_sig_fmt(struct fw_unit *unit, unsigned int rate,
  29                             enum avc_general_plug_dir dir,
  30                             unsigned short pid)
  31 {
  32         unsigned int sfc;
  33         u8 *buf;
  34         bool flag;
  35         int err;
  36
  37         flag = false;
  38         for (sfc = 0; sfc < CIP_SFC_COUNT; sfc++) {
  39                 if (amdtp_rate_table[sfc] == rate) {
  40                         flag = true;
  41                         break;
  42                 }
  43         }
  44         if (!flag)
  45                 return -EINVAL;
  46
  47         buf = kzalloc(8, GFP_KERNEL);
  48         if (buf == NULL)
  49                 return -ENOMEM;
  50
  51         buf[0] = 0x00;          /* AV/C CONTROL */
  52         buf[1] = 0xff;          /* UNIT */
  53         if (dir == AVC_GENERAL_PLUG_DIR_IN)
  54                 buf[2] = 0x19;  /* INPUT PLUG SIGNAL FORMAT */
  55         else
  56                 buf[2] = 0x18;  /* OUTPUT PLUG SIGNAL FORMAT */
  57         buf[3] = 0xff & pid;    /* plug id */
  58         buf[4] = 0x90;          /* EOH_1, Form_1, FMT. AM824 */
  59         buf[5] = 0x07 & sfc;    /* FDF-hi. AM824, frequency */
  60         buf[6] = 0xff;          /* FDF-mid. AM824, SYT hi (not used)*/
  61         buf[7] = 0xff;          /* FDF-low. AM824, SYT lo (not used) */
  62
  63         /* do transaction and check buf[1-5] are the same against command */
  64         err = fcp_avc_transaction(unit, buf, 8, buf, 8,
  65                                   BIT(1) | BIT(2) | BIT(3) | BIT(4) | BIT(5));
  66         if (err < 0)
  67                 ;
  68         else if (err < 8)
  69                 err = -EIO;
  70         else if (buf[0] == 0x08) /* NOT IMPLEMENTED */
  71                 err = -ENOSYS;
  72         else if (buf[0] == 0x0a) /* REJECTED */
  73                 err = -EINVAL;
  74         if (err < 0)
  75                 goto end;
  76
  77         err = 0;
  78 end:
  79         kfree(buf);
  80         return err;
  81 }
  82 EXPORT_SYMBOL(avc_general_set_sig_fmt);
  83
  84 int avc_general_get_sig_fmt(struct fw_unit *unit, unsigned int *rate,
  85                             enum avc_general_plug_dir dir,
  86                             unsigned short pid)
  87 {
  88         unsigned int sfc;
  89         u8 *buf;
  90         int err;
  91
  92         buf = kzalloc(8, GFP_KERNEL);
  93         if (buf == NULL)
  94                 return -ENOMEM;
  95
  96         buf[0] = 0x01;          /* AV/C STATUS */
  97         buf[1] = 0xff;          /* Unit */
  98         if (dir == AVC_GENERAL_PLUG_DIR_IN)
  99                 buf[2] = 0x19;  /* INPUT PLUG SIGNAL FORMAT */
 100         else
 101                 buf[2] = 0x18;  /* OUTPUT PLUG SIGNAL FORMAT */
 102         buf[3] = 0xff & pid;    /* plug id */
 103         buf[4] = 0x90;          /* EOH_1, Form_1, FMT. AM824 */
 104         buf[5] = 0xff;          /* FDF-hi. AM824, frequency */
 105         buf[6] = 0xff;          /* FDF-mid. AM824, SYT hi (not used) */
 106         buf[7] = 0xff;          /* FDF-low. AM824, SYT lo (not used) */
 107
 108         /* do transaction and check buf[1-4] are the same against command */
 109         err = fcp_avc_transaction(unit, buf, 8, buf, 8,
 110                                   BIT(1) | BIT(2) | BIT(3) | BIT(4));
 111         if (err < 0)
 112                 ;
 113         else if (err < 8)
 114                 err = -EIO;
 115         else if (buf[0] == 0x08) /* NOT IMPLEMENTED */
 116                 err = -ENOSYS;
 117         else if (buf[0] == 0x0a) /* REJECTED */
 118                 err = -EINVAL;
 119         else if (buf[0] == 0x0b) /* IN TRANSITION */
 120                 err = -EAGAIN;
 121         if (err < 0)
 122                 goto end;
 123
 124         /* check sfc field and pick up rate */
 125         sfc = 0x07 & buf[5];
 126         if (sfc >= CIP_SFC_COUNT) {
 127                 err = -EAGAIN;  /* also in transition */
 128                 goto end;
 129         }
 130
 131         *rate = amdtp_rate_table[sfc];
 132         err = 0;
 133 end:
 134         kfree(buf);
 135         return err;
 136 }
 137 EXPORT_SYMBOL(avc_general_get_sig_fmt);
 138
 139 int avc_general_get_plug_info(struct fw_unit *unit, unsigned int subunit_type,
 140                               unsigned int subunit_id, unsigned int subfunction,
 141                               u8 info[AVC_PLUG_INFO_BUF_BYTES])
 142 {
 143         u8 *buf;
 144         int err;
 145
 146         /* extended subunit in spec.4.2 is not supported */
 147         if ((subunit_type == 0x1E) || (subunit_id == 5))
 148                 return -EINVAL;
 149
 150         buf = kzalloc(8, GFP_KERNEL);
 151         if (buf == NULL)
 152                 return -ENOMEM;
 153
 154         buf[0] = 0x01;  /* AV/C STATUS */
 155         /* UNIT or Subunit, Functionblock */
 156         buf[1] = ((subunit_type & 0x1f) << 3) | (subunit_id & 0x7);
 157         buf[2] = 0x02;  /* PLUG INFO */
 158         buf[3] = 0xff & subfunction;
 159
 160         err = fcp_avc_transaction(unit, buf, 8, buf, 8, BIT(1) | BIT(2));
 161         if (err < 0)
 162                 ;
 163         else if (err < 8)
 164                 err = -EIO;
 165         else if (buf[0] == 0x08) /* NOT IMPLEMENTED */
 166                 err = -ENOSYS;
 167         else if (buf[0] == 0x0a) /* REJECTED */
 168                 err = -EINVAL;
 169         else if (buf[0] == 0x0b) /* IN TRANSITION */
 170                 err = -EAGAIN;
 171         if (err < 0)
 172                 goto end;
 173
 174         info[0] = buf[4];
 175         info[1] = buf[5];
 176         info[2] = buf[6];
 177         info[3] = buf[7];
 178
 179         err = 0;
 180 end:
 181         kfree(buf);
 182         return err;
 183 }
 184 EXPORT_SYMBOL(avc_general_get_plug_info);
 185
 186 static DEFINE_SPINLOCK(transactions_lock);
 187 static LIST_HEAD(transactions);
 188
 189 enum fcp_state {
 190         STATE_PENDING,
 191         STATE_BUS_RESET,
 192         STATE_COMPLETE,
 193         STATE_DEFERRED,
 194 };
 195
 196 struct fcp_transaction {
 197         struct list_head list;
 198         struct fw_unit *unit;
 199         void *response_buffer;
 200         unsigned int response_size;
 201         unsigned int response_match_bytes;
 202         enum fcp_state state;
 203         wait_queue_head_t wait;
 204         bool deferrable;
 205 };
 206
 207 /**
 208  * fcp_avc_transaction - send an AV/C command and wait for its response
 209  * @unit: a unit on the target device
 210  * @command: a buffer containing the command frame; must be DMA-able
 211  * @command_size: the size of @command
 212  * @response: a buffer for the response frame
 213  * @response_size: the maximum size of @response
 214  * @response_match_bytes: a bitmap specifying the bytes used to detect the
 215  *                        correct response frame
 216  *
 217  * This function sends a FCP command frame to the target and waits for the
 218  * corresponding response frame to be returned.
 219  *
 220  * Because it is possible for multiple FCP transactions to be active at the
 221  * same time, the correct response frame is detected by the value of certain
 222  * bytes.  These bytes must be set in @response before calling this function,
 223  * and the corresponding bits must be set in @response_match_bytes.
 224  *
 225  * @command and @response can point to the same buffer.
 226  *
 227  * Returns the actual size of the response frame, or a negative error code.
 228  */
 229 int fcp_avc_transaction(struct fw_unit *unit,
 230                         const void *command, unsigned int command_size,
 231                         void *response, unsigned int response_size,
 232                         unsigned int response_match_bytes)
 233 {
 234         struct fcp_transaction t;
 235         int tcode, ret, tries = 0;
 236
 237         t.unit = unit;
 238         t.response_buffer = response;
 239         t.response_size = response_size;
 240         t.response_match_bytes = response_match_bytes;
 241         t.state = STATE_PENDING;
 242         init_waitqueue_head(&t.wait);
 243
 244         if (*(const u8 *)command == 0x00 || *(const u8 *)command == 0x03)
 245                 t.deferrable = true;
 246
 247         spin_lock_irq(&transactions_lock);
 248         list_add_tail(&t.list, &transactions);
 249         spin_unlock_irq(&transactions_lock);
 250
 251         for (;;) {
 252                 tcode = command_size == 4 ? TCODE_WRITE_QUADLET_REQUEST
 253                                           : TCODE_WRITE_BLOCK_REQUEST;
 254                 ret = snd_fw_transaction(t.unit, tcode,
 255                                          CSR_REGISTER_BASE + CSR_FCP_COMMAND,
 256                                          (void *)command, command_size, 0);
 257                 if (ret < 0)
 258                         break;
 259 deferred:
 260                 wait_event_timeout(t.wait, t.state != STATE_PENDING,
 261                                    msecs_to_jiffies(FCP_TIMEOUT_MS));
 262
 263                 if (t.state == STATE_DEFERRED) {
 264                         /*
 265                          * 'AV/C General Specification' define no time limit
 266                          * on command completion once an INTERIM response has
 267                          * been sent. but we promise to finish this function
 268                          * for a caller. Here we use FCP_TIMEOUT_MS for next
 269                          * interval. This is not in the specification.
 270                          */
 271                         t.state = STATE_PENDING;
 272                         goto deferred;
 273                 } else if (t.state == STATE_COMPLETE) {
 274                         ret = t.response_size;
 275                         break;
 276                 } else if (t.state == STATE_BUS_RESET) {
 277                         msleep(ERROR_DELAY_MS);
 278                 } else if (++tries >= ERROR_RETRIES) {
 279                         dev_err(&t.unit->device, "FCP command timed out\n");
 280                         ret = -EIO;
 281                         break;
 282                 }
 283         }
 284
 285         spin_lock_irq(&transactions_lock);
 286         list_del(&t.list);
 287         spin_unlock_irq(&transactions_lock);
 288
 289         return ret;
 290 }
 291 EXPORT_SYMBOL(fcp_avc_transaction);
 292
 293 /**
 294  * fcp_bus_reset - inform the target handler about a bus reset
 295  * @unit: the unit that might be used by fcp_avc_transaction()
 296  *
 297  * This function must be called from the driver's .update handler to inform
 298  * the FCP transaction handler that a bus reset has happened.  Any pending FCP
 299  * transactions are retried.
 300  */
 301 void fcp_bus_reset(struct fw_unit *unit)
 302 {
 303         struct fcp_transaction *t;
 304
 305         spin_lock_irq(&transactions_lock);
 306         list_for_each_entry(t, &transactions, list) {
 307                 if (t->unit == unit &&
 308                     (t->state == STATE_PENDING ||
 309                      t->state == STATE_DEFERRED)) {
 310                         t->state = STATE_BUS_RESET;
 311                         wake_up(&t->wait);
 312                 }
 313         }
 314         spin_unlock_irq(&transactions_lock);
 315 }
 316 EXPORT_SYMBOL(fcp_bus_reset);
 317
 318 /* checks whether the response matches the masked bytes in response_buffer */
 319 static bool is_matching_response(struct fcp_transaction *transaction,
 320                                  const void *response, size_t length)
 321 {
 322         const u8 *p1, *p2;
 323         unsigned int mask, i;
 324
 325         p1 = response;
 326         p2 = transaction->response_buffer;
 327         mask = transaction->response_match_bytes;
 328
 329         for (i = 0; ; ++i) {
 330                 if ((mask & 1) && p1[i] != p2[i])
 331                         return false;
 332                 mask >>= 1;
 333                 if (!mask)
 334                         return true;
 335                 if (--length == 0)
 336                         return false;
 337         }
 338 }
 339
 340 static void fcp_response(struct fw_card *card, struct fw_request *request,
 341                          int tcode, int destination, int source,
 342                          int generation, unsigned long long offset,
 343                          void *data, size_t length, void *callback_data)
 344 {
 345         struct fcp_transaction *t;
 346         unsigned long flags;
 347
 348         if (length < 1 || (*(const u8 *)data & 0xf0) != CTS_AVC)
 349                 return;
 350
 351         spin_lock_irqsave(&transactions_lock, flags);
 352         list_for_each_entry(t, &transactions, list) {
 353                 struct fw_device *device = fw_parent_device(t->unit);
 354                 if (device->card != card ||
 355                     device->generation != generation)
 356                         continue;
 357                 smp_rmb(); /* node_id vs. generation */
 358                 if (device->node_id != source)
 359                         continue;
 360
 361                 if (t->state == STATE_PENDING &&
 362                     is_matching_response(t, data, length)) {
 363                         if (t->deferrable && *(const u8 *)data == 0x0f) {
 364                                 t->state = STATE_DEFERRED;
 365                         } else {
 366                                 t->state = STATE_COMPLETE;
 367                                 t->response_size = min_t(unsigned int, length,
 368                                                          t->response_size);
 369                                 memcpy(t->response_buffer, data,
 370                                        t->response_size);
 371                         }
 372                         wake_up(&t->wait);
 373                 }
 374         }
 375         spin_unlock_irqrestore(&transactions_lock, flags);
 376 }
 377
 378 static struct fw_address_handler response_register_handler = {
 379         .length = 0x200,
 380         .address_callback = fcp_response,
 381 };
 382
 383 static int __init fcp_module_init(void)
 384 {
 385         static const struct fw_address_region response_register_region = {
 386                 .start = CSR_REGISTER_BASE + CSR_FCP_RESPONSE,
 387                 .end = CSR_REGISTER_BASE + CSR_FCP_END,
 388         };
 389
 390         fw_core_add_address_handler(&response_register_handler,
 391                                     &response_register_region);
 392
 393         return 0;
 394 }
 395
 396 static void __exit fcp_module_exit(void)
 397 {
 398         WARN_ON(!list_empty(&transactions));
 399         fw_core_remove_address_handler(&response_register_handler);
 400 }
 401
 402 module_init(fcp_module_init);
 403 module_exit(fcp_module_exit);