drivers/media/pci/saa7164/saa7164-bus.c

   1 /*
   2  *  Driver for the NXP SAA7164 PCIe bridge
   3  *
   4  *  Copyright (c) 2010 Steven Toth <stoth@kernellabs.com>
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *
  15  *  GNU General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU General Public License
  18  *  along with this program; if not, write to the Free Software
  19  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  */
  21
  22 #include "saa7164.h"
  23
  24 /* The message bus to/from the firmware is a ring buffer in PCI address
  25  * space. Establish the defaults.
  26  */
  27 int saa7164_bus_setup(struct saa7164_dev *dev)
  28 {
  29         struct tmComResBusInfo *b       = &dev->bus;
  30
  31         mutex_init(&b->lock);
  32
  33         b->Type                 = TYPE_BUS_PCIe;
  34         b->m_wMaxReqSize        = SAA_DEVICE_MAXREQUESTSIZE;
  35
  36         b->m_pdwSetRing         = (u8 *)(dev->bmmio +
  37                 ((u32)dev->busdesc.CommandRing));
  38
  39         b->m_dwSizeSetRing      = SAA_DEVICE_BUFFERBLOCKSIZE;
  40
  41         b->m_pdwGetRing         = (u8 *)(dev->bmmio +
  42                 ((u32)dev->busdesc.ResponseRing));
  43
  44         b->m_dwSizeGetRing      = SAA_DEVICE_BUFFERBLOCKSIZE;
  45
  46         b->m_dwSetWritePos      = ((u32)dev->intfdesc.BARLocation) +
  47                 (2 * sizeof(u64));
  48         b->m_dwSetReadPos       = b->m_dwSetWritePos + (1 * sizeof(u32));
  49
  50         b->m_dwGetWritePos      = b->m_dwSetWritePos + (2 * sizeof(u32));
  51         b->m_dwGetReadPos       = b->m_dwSetWritePos + (3 * sizeof(u32));
  52
  53         return 0;
  54 }
  55
  56 void saa7164_bus_dump(struct saa7164_dev *dev)
  57 {
  58         struct tmComResBusInfo *b = &dev->bus;
  59
  60         dprintk(DBGLVL_BUS, "Dumping the bus structure:\n");
  61         dprintk(DBGLVL_BUS, " .type             = %d\n", b->Type);
  62         dprintk(DBGLVL_BUS, " .dev->bmmio       = 0x%p\n", dev->bmmio);
  63         dprintk(DBGLVL_BUS, " .m_wMaxReqSize    = 0x%x\n", b->m_wMaxReqSize);
  64         dprintk(DBGLVL_BUS, " .m_pdwSetRing     = 0x%p\n", b->m_pdwSetRing);
  65         dprintk(DBGLVL_BUS, " .m_dwSizeSetRing  = 0x%x\n", b->m_dwSizeSetRing);
  66         dprintk(DBGLVL_BUS, " .m_pdwGetRing     = 0x%p\n", b->m_pdwGetRing);
  67         dprintk(DBGLVL_BUS, " .m_dwSizeGetRing  = 0x%x\n", b->m_dwSizeGetRing);
  68
  69         dprintk(DBGLVL_BUS, " .m_dwSetReadPos   = 0x%x (0x%08x)\n",
  70                 b->m_dwSetReadPos, saa7164_readl(b->m_dwSetReadPos));
  71
  72         dprintk(DBGLVL_BUS, " .m_dwSetWritePos  = 0x%x (0x%08x)\n",
  73                 b->m_dwSetWritePos, saa7164_readl(b->m_dwSetWritePos));
  74
  75         dprintk(DBGLVL_BUS, " .m_dwGetReadPos   = 0x%x (0x%08x)\n",
  76                 b->m_dwGetReadPos, saa7164_readl(b->m_dwGetReadPos));
  77
  78         dprintk(DBGLVL_BUS, " .m_dwGetWritePos  = 0x%x (0x%08x)\n",
  79                 b->m_dwGetWritePos, saa7164_readl(b->m_dwGetWritePos));
  80
  81 }
  82
  83 /* Intensionally throw a BUG() if the state of the message bus looks corrupt */
  84 void saa7164_bus_verify(struct saa7164_dev *dev)
  85 {
  86         struct tmComResBusInfo *b = &dev->bus;
  87         int bug = 0;
  88
  89         if (saa7164_readl(b->m_dwSetReadPos) > b->m_dwSizeSetRing)
  90                 bug++;
  91
  92         if (saa7164_readl(b->m_dwSetWritePos) > b->m_dwSizeSetRing)
  93                 bug++;
  94
  95         if (saa7164_readl(b->m_dwGetReadPos) > b->m_dwSizeGetRing)
  96                 bug++;
  97
  98         if (saa7164_readl(b->m_dwGetWritePos) > b->m_dwSizeGetRing)
  99                 bug++;
 100
 101         if (bug) {
 102                 saa_debug = 0xffff; /* Ensure we get the bus dump */
 103                 saa7164_bus_dump(dev);
 104                 saa_debug = 1024; /* Ensure we get the bus dump */
 105                 BUG();
 106         }
 107 }
 108
 109 void saa7164_bus_dumpmsg(struct saa7164_dev *dev, struct tmComResInfo* m,
 110         void *buf)
 111 {
 112         dprintk(DBGLVL_BUS, "Dumping msg structure:\n");
 113         dprintk(DBGLVL_BUS, " .id               = %d\n",   m->id);
 114         dprintk(DBGLVL_BUS, " .flags            = 0x%x\n", m->flags);
 115         dprintk(DBGLVL_BUS, " .size             = 0x%x\n", m->size);
 116         dprintk(DBGLVL_BUS, " .command          = 0x%x\n", m->command);
 117         dprintk(DBGLVL_BUS, " .controlselector  = 0x%x\n", m->controlselector);
 118         dprintk(DBGLVL_BUS, " .seqno            = %d\n",   m->seqno);
 119         if (buf)
 120                 dprintk(DBGLVL_BUS, " .buffer (ignored)\n");
 121 }
 122
 123 /*
 124  * Places a command or a response on the bus. The implementation does not
 125  * know if it is a command or a response it just places the data on the
 126  * bus depending on the bus information given in the struct tmComResBusInfo
 127  * structure. If the command or response does not fit into the bus ring
 128  * buffer it will be refused.
 129  *
 130  * Return Value:
 131  *  SAA_OK     The function executed successfully.
 132  *  < 0        One or more members are not initialized.
 133  */
 134 int saa7164_bus_set(struct saa7164_dev *dev, struct tmComResInfo* msg,
 135         void *buf)
 136 {
 137         struct tmComResBusInfo *bus = &dev->bus;
 138         u32 bytes_to_write, free_write_space, timeout, curr_srp, curr_swp;
 139         u32 new_swp, space_rem;
 140         int ret = SAA_ERR_BAD_PARAMETER;
 141
 142         if (!msg) {
 143                 printk(KERN_ERR "%s() !msg\n", __func__);
 144                 return SAA_ERR_BAD_PARAMETER;
 145         }
 146
 147         dprintk(DBGLVL_BUS, "%s()\n", __func__);
 148
 149         saa7164_bus_verify(dev);
 150
 151         msg->size = cpu_to_le16(msg->size);
 152         msg->command = cpu_to_le32(msg->command);
 153         msg->controlselector = cpu_to_le16(msg->controlselector);
 154
 155         if (msg->size > dev->bus.m_wMaxReqSize) {
 156                 printk(KERN_ERR "%s() Exceeded dev->bus.m_wMaxReqSize\n",
 157                         __func__);
 158                 return SAA_ERR_BAD_PARAMETER;
 159         }
 160
 161         if ((msg->size > 0) && (buf == NULL)) {
 162                 printk(KERN_ERR "%s() Missing message buffer\n", __func__);
 163                 return SAA_ERR_BAD_PARAMETER;
 164         }
 165
 166         /* Lock the bus from any other access */
 167         mutex_lock(&bus->lock);
 168
 169         bytes_to_write = sizeof(*msg) + msg->size;
 170         free_write_space = 0;
 171         timeout = SAA_BUS_TIMEOUT;
 172         curr_srp = le32_to_cpu(saa7164_readl(bus->m_dwSetReadPos));
 173         curr_swp = le32_to_cpu(saa7164_readl(bus->m_dwSetWritePos));
 174
 175         /* Deal with ring wrapping issues */
 176         if (curr_srp > curr_swp)
 177                 /* Deal with the wrapped ring */
 178                 free_write_space = curr_srp - curr_swp;
 179         else
 180                 /* The ring has not wrapped yet */
 181                 free_write_space = (curr_srp + bus->m_dwSizeSetRing) - curr_swp;
 182
 183         dprintk(DBGLVL_BUS, "%s() bytes_to_write = %d\n", __func__,
 184                 bytes_to_write);
 185
 186         dprintk(DBGLVL_BUS, "%s() free_write_space = %d\n", __func__,
 187                 free_write_space);
 188
 189         dprintk(DBGLVL_BUS, "%s() curr_srp = %x\n", __func__, curr_srp);
 190         dprintk(DBGLVL_BUS, "%s() curr_swp = %x\n", __func__, curr_swp);
 191
 192         /* Process the msg and write the content onto the bus */
 193         while (bytes_to_write >= free_write_space) {
 194
 195                 if (timeout-- == 0) {
 196                         printk(KERN_ERR "%s() bus timeout\n", __func__);
 197                         ret = SAA_ERR_NO_RESOURCES;
 198                         goto out;
 199                 }
 200
 201                 /* TODO: Review this delay, efficient? */
 202                 /* Wait, allowing the hardware fetch time */
 203                 mdelay(1);
 204
 205                 /* Check the space usage again */
 206                 curr_srp = le32_to_cpu(saa7164_readl(bus->m_dwSetReadPos));
 207
 208                 /* Deal with ring wrapping issues */
 209                 if (curr_srp > curr_swp)
 210                         /* Deal with the wrapped ring */
 211                         free_write_space = curr_srp - curr_swp;
 212                 else
 213                         /* Read didn't wrap around the buffer */
 214                         free_write_space = (curr_srp + bus->m_dwSizeSetRing) -
 215                                 curr_swp;
 216
 217         }
 218
 219         /* Calculate the new write position */
 220         new_swp = curr_swp + bytes_to_write;
 221
 222         dprintk(DBGLVL_BUS, "%s() new_swp = %x\n", __func__, new_swp);
 223         dprintk(DBGLVL_BUS, "%s() bus->m_dwSizeSetRing = %x\n", __func__,
 224                 bus->m_dwSizeSetRing);
 225
 226         /* Mental Note: line 462 tmmhComResBusPCIe.cpp */
 227
 228         /* Check if we're going to wrap again */
 229         if (new_swp > bus->m_dwSizeSetRing) {
 230
 231                 /* Ring wraps */
 232                 new_swp -= bus->m_dwSizeSetRing;
 233
 234                 space_rem = bus->m_dwSizeSetRing - curr_swp;
 235
 236                 dprintk(DBGLVL_BUS, "%s() space_rem = %x\n", __func__,
 237                         space_rem);
 238
 239                 dprintk(DBGLVL_BUS, "%s() sizeof(*msg) = %d\n", __func__,
 240                         (u32)sizeof(*msg));
 241
 242                 if (space_rem < sizeof(*msg)) {
 243                         dprintk(DBGLVL_BUS, "%s() tr4\n", __func__);
 244
 245                         /* Split the msg into pieces as the ring wraps */
 246                         memcpy(bus->m_pdwSetRing + curr_swp, msg, space_rem);
 247                         memcpy(bus->m_pdwSetRing, (u8 *)msg + space_rem,
 248                                 sizeof(*msg) - space_rem);
 249
 250                         memcpy(bus->m_pdwSetRing + sizeof(*msg) - space_rem,
 251                                 buf, msg->size);
 252
 253                 } else if (space_rem == sizeof(*msg)) {
 254                         dprintk(DBGLVL_BUS, "%s() tr5\n", __func__);
 255
 256                         /* Additional data at the beginning of the ring */
 257                         memcpy(bus->m_pdwSetRing + curr_swp, msg, sizeof(*msg));
 258                         memcpy(bus->m_pdwSetRing, buf, msg->size);
 259
 260                 } else {
 261                         /* Additional data wraps around the ring */
 262                         memcpy(bus->m_pdwSetRing + curr_swp, msg, sizeof(*msg));
 263                         if (msg->size > 0) {
 264                                 memcpy(bus->m_pdwSetRing + curr_swp +
 265                                         sizeof(*msg), buf, space_rem -
 266                                         sizeof(*msg));
 267                                 memcpy(bus->m_pdwSetRing, (u8 *)buf +
 268                                         space_rem - sizeof(*msg),
 269                                         bytes_to_write - space_rem);
 270                         }
 271
 272                 }
 273
 274         } /* (new_swp > bus->m_dwSizeSetRing) */
 275         else {
 276                 dprintk(DBGLVL_BUS, "%s() tr6\n", __func__);
 277
 278                 /* The ring buffer doesn't wrap, two simple copies */
 279                 memcpy(bus->m_pdwSetRing + curr_swp, msg, sizeof(*msg));
 280                 memcpy(bus->m_pdwSetRing + curr_swp + sizeof(*msg), buf,
 281                         msg->size);
 282         }
 283
 284         dprintk(DBGLVL_BUS, "%s() new_swp = %x\n", __func__, new_swp);
 285
 286         /* Update the bus write position */
 287         saa7164_writel(bus->m_dwSetWritePos, cpu_to_le32(new_swp));
 288         ret = SAA_OK;
 289
 290 out:
 291         saa7164_bus_dump(dev);
 292         mutex_unlock(&bus->lock);
 293         saa7164_bus_verify(dev);
 294         return ret;
 295 }
 296
 297 /*
 298  * Receive a command or a response from the bus. The implementation does not
 299  * know if it is a command or a response it simply dequeues the data,
 300  * depending on the bus information given in the struct tmComResBusInfo
 301  * structure.
 302  *
 303  * Return Value:
 304  *  0          The function executed successfully.
 305  *  < 0        One or more members are not initialized.
 306  */
 307 int saa7164_bus_get(struct saa7164_dev *dev, struct tmComResInfo* msg,
 308         void *buf, int peekonly)
 309 {
 310         struct tmComResBusInfo *bus = &dev->bus;
 311         u32 bytes_to_read, write_distance, curr_grp, curr_gwp,
 312                 new_grp, buf_size, space_rem;
 313         struct tmComResInfo msg_tmp;
 314         int ret = SAA_ERR_BAD_PARAMETER;
 315
 316         saa7164_bus_verify(dev);
 317
 318         if (msg == NULL)
 319                 return ret;
 320
 321         if (msg->size > dev->bus.m_wMaxReqSize) {
 322                 printk(KERN_ERR "%s() Exceeded dev->bus.m_wMaxReqSize\n",
 323                         __func__);
 324                 return ret;
 325         }
 326
 327         if ((peekonly == 0) && (msg->size > 0) && (buf == NULL)) {
 328                 printk(KERN_ERR
 329                         "%s() Missing msg buf, size should be %d bytes\n",
 330                         __func__, msg->size);
 331                 return ret;
 332         }
 333
 334         mutex_lock(&bus->lock);
 335
 336         /* Peek the bus to see if a msg exists, if it's not what we're expecting
 337          * then return cleanly else read the message from the bus.
 338          */
 339         curr_gwp = le32_to_cpu(saa7164_readl(bus->m_dwGetWritePos));
 340         curr_grp = le32_to_cpu(saa7164_readl(bus->m_dwGetReadPos));
 341
 342         if (curr_gwp == curr_grp) {
 343                 ret = SAA_ERR_EMPTY;
 344                 goto out;
 345         }
 346
 347         bytes_to_read = sizeof(*msg);
 348
 349         /* Calculate write distance to current read position */
 350         write_distance = 0;
 351         if (curr_gwp >= curr_grp)
 352                 /* Write doesn't wrap around the ring */
 353                 write_distance = curr_gwp - curr_grp;
 354         else
 355                 /* Write wraps around the ring */
 356                 write_distance = curr_gwp + bus->m_dwSizeGetRing - curr_grp;
 357
 358         if (bytes_to_read > write_distance) {
 359                 printk(KERN_ERR "%s() No message/response found\n", __func__);
 360                 ret = SAA_ERR_INVALID_COMMAND;
 361                 goto out;
 362         }
 363
 364         /* Calculate the new read position */
 365         new_grp = curr_grp + bytes_to_read;
 366         if (new_grp > bus->m_dwSizeGetRing) {
 367
 368                 /* Ring wraps */
 369                 new_grp -= bus->m_dwSizeGetRing;
 370                 space_rem = bus->m_dwSizeGetRing - curr_grp;
 371
 372                 memcpy(&msg_tmp, bus->m_pdwGetRing + curr_grp, space_rem);
 373                 memcpy((u8 *)&msg_tmp + space_rem, bus->m_pdwGetRing,
 374                         bytes_to_read - space_rem);
 375
 376         } else {
 377                 /* No wrapping */
 378                 memcpy(&msg_tmp, bus->m_pdwGetRing + curr_grp, bytes_to_read);
 379         }
 380
 381         /* No need to update the read positions, because this was a peek */
 382         /* If the caller specifically want to peek, return */
 383         if (peekonly) {
 384                 memcpy(msg, &msg_tmp, sizeof(*msg));
 385                 goto peekout;
 386         }
 387
 388         /* Check if the command/response matches what is expected */
 389         if ((msg_tmp.id != msg->id) || (msg_tmp.command != msg->command) ||
 390                 (msg_tmp.controlselector != msg->controlselector) ||
 391                 (msg_tmp.seqno != msg->seqno) || (msg_tmp.size != msg->size)) {
 392
 393                 printk(KERN_ERR "%s() Unexpected msg miss-match\n", __func__);
 394                 saa7164_bus_dumpmsg(dev, msg, buf);
 395                 saa7164_bus_dumpmsg(dev, &msg_tmp, NULL);
 396                 ret = SAA_ERR_INVALID_COMMAND;
 397                 goto out;
 398         }
 399
 400         /* Get the actual command and response from the bus */
 401         buf_size = msg->size;
 402
 403         bytes_to_read = sizeof(*msg) + msg->size;
 404         /* Calculate write distance to current read position */
 405         write_distance = 0;
 406         if (curr_gwp >= curr_grp)
 407                 /* Write doesn't wrap around the ring */
 408                 write_distance = curr_gwp - curr_grp;
 409         else
 410                 /* Write wraps around the ring */
 411                 write_distance = curr_gwp + bus->m_dwSizeGetRing - curr_grp;
 412
 413         if (bytes_to_read > write_distance) {
 414                 printk(KERN_ERR "%s() Invalid bus state, missing msg "
 415                         "or mangled ring, faulty H/W / bad code?\n", __func__);
 416                 ret = SAA_ERR_INVALID_COMMAND;
 417                 goto out;
 418         }
 419
 420         /* Calculate the new read position */
 421         new_grp = curr_grp + bytes_to_read;
 422         if (new_grp > bus->m_dwSizeGetRing) {
 423
 424                 /* Ring wraps */
 425                 new_grp -= bus->m_dwSizeGetRing;
 426                 space_rem = bus->m_dwSizeGetRing - curr_grp;
 427
 428                 if (space_rem < sizeof(*msg)) {
 429                         /* msg wraps around the ring */
 430                         memcpy(msg, bus->m_pdwGetRing + curr_grp, space_rem);
 431                         memcpy((u8 *)msg + space_rem, bus->m_pdwGetRing,
 432                                 sizeof(*msg) - space_rem);
 433                         if (buf)
 434                                 memcpy(buf, bus->m_pdwGetRing + sizeof(*msg) -
 435                                         space_rem, buf_size);
 436
 437                 } else if (space_rem == sizeof(*msg)) {
 438                         memcpy(msg, bus->m_pdwGetRing + curr_grp, sizeof(*msg));
 439                         if (buf)
 440                                 memcpy(buf, bus->m_pdwGetRing, buf_size);
 441                 } else {
 442                         /* Additional data wraps around the ring */
 443                         memcpy(msg, bus->m_pdwGetRing + curr_grp, sizeof(*msg));
 444                         if (buf) {
 445                                 memcpy(buf, bus->m_pdwGetRing + curr_grp +
 446                                         sizeof(*msg), space_rem - sizeof(*msg));
 447                                 memcpy(buf + space_rem - sizeof(*msg),
 448                                         bus->m_pdwGetRing, bytes_to_read -
 449                                         space_rem);
 450                         }
 451
 452                 }
 453
 454         } else {
 455                 /* No wrapping */
 456                 memcpy(msg, bus->m_pdwGetRing + curr_grp, sizeof(*msg));
 457                 if (buf)
 458                         memcpy(buf, bus->m_pdwGetRing + curr_grp + sizeof(*msg),
 459                                 buf_size);
 460         }
 461
 462         /* Update the read positions, adjusting the ring */
 463         saa7164_writel(bus->m_dwGetReadPos, cpu_to_le32(new_grp));
 464
 465 peekout:
 466         msg->size = le16_to_cpu(msg->size);
 467         msg->command = le32_to_cpu(msg->command);
 468         msg->controlselector = le16_to_cpu(msg->controlselector);
 469         ret = SAA_OK;
 470 out:
 471         mutex_unlock(&bus->lock);
 472         saa7164_bus_verify(dev);
 473         return ret;
 474 }
 475