sound/firewire/fcp.c

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