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