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.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); 398