1 /* 2 * Freescale DMA ALSA SoC PCM driver 3 * 4 * Author: Timur Tabi <timur@freescale.com> 5 * 6 * Copyright 2007-2008 Freescale Semiconductor, Inc. This file is licensed 7 * under the terms of the GNU General Public License version 2. This 8 * program is licensed "as is" without any warranty of any kind, whether 9 * express or implied. 10 * 11 * This driver implements ASoC support for the Elo DMA controller, which is 12 * the DMA controller on Freescale 83xx, 85xx, and 86xx SOCs. In ALSA terms, 13 * the PCM driver is what handles the DMA buffer. 14 */ 15 16 #include <linux/module.h> 17 #include <linux/init.h> 18 #include <linux/platform_device.h> 19 #include <linux/dma-mapping.h> 20 #include <linux/interrupt.h> 21 #include <linux/delay.h> 22 23 #include <sound/core.h> 24 #include <sound/pcm.h> 25 #include <sound/pcm_params.h> 26 #include <sound/soc.h> 27 28 #include <asm/io.h> 29 30 #include "fsl_dma.h" 31 32 /* 33 * The formats that the DMA controller supports, which is anything 34 * that is 8, 16, or 32 bits. 35 */ 36 #define FSLDMA_PCM_FORMATS (SNDRV_PCM_FMTBIT_S8 | \ 37 SNDRV_PCM_FMTBIT_U8 | \ 38 SNDRV_PCM_FMTBIT_S16_LE | \ 39 SNDRV_PCM_FMTBIT_S16_BE | \ 40 SNDRV_PCM_FMTBIT_U16_LE | \ 41 SNDRV_PCM_FMTBIT_U16_BE | \ 42 SNDRV_PCM_FMTBIT_S24_LE | \ 43 SNDRV_PCM_FMTBIT_S24_BE | \ 44 SNDRV_PCM_FMTBIT_U24_LE | \ 45 SNDRV_PCM_FMTBIT_U24_BE | \ 46 SNDRV_PCM_FMTBIT_S32_LE | \ 47 SNDRV_PCM_FMTBIT_S32_BE | \ 48 SNDRV_PCM_FMTBIT_U32_LE | \ 49 SNDRV_PCM_FMTBIT_U32_BE) 50 51 #define FSLDMA_PCM_RATES (SNDRV_PCM_RATE_5512 | SNDRV_PCM_RATE_8000_192000 | \ 52 SNDRV_PCM_RATE_CONTINUOUS) 53 54 /* DMA global data. This structure is used by fsl_dma_open() to determine 55 * which DMA channels to assign to a substream. Unfortunately, ASoC V1 does 56 * not allow the machine driver to provide this information to the PCM 57 * driver in advance, and there's no way to differentiate between the two 58 * DMA controllers. So for now, this driver only supports one SSI device 59 * using two DMA channels. We cannot support multiple DMA devices. 60 * 61 * ssi_stx_phys: bus address of SSI STX register 62 * ssi_srx_phys: bus address of SSI SRX register 63 * dma_channel: pointer to the DMA channel's registers 64 * irq: IRQ for this DMA channel 65 * assigned: set to 1 if that DMA channel is assigned to a substream 66 */ 67 static struct { 68 dma_addr_t ssi_stx_phys; 69 dma_addr_t ssi_srx_phys; 70 struct ccsr_dma_channel __iomem *dma_channel[2]; 71 unsigned int irq[2]; 72 unsigned int assigned[2]; 73 } dma_global_data; 74 75 /* 76 * The number of DMA links to use. Two is the bare minimum, but if you 77 * have really small links you might need more. 78 */ 79 #define NUM_DMA_LINKS 2 80 81 /** fsl_dma_private: p-substream DMA data 82 * 83 * Each substream has a 1-to-1 association with a DMA channel. 84 * 85 * The link[] array is first because it needs to be aligned on a 32-byte 86 * boundary, so putting it first will ensure alignment without padding the 87 * structure. 88 * 89 * @link[]: array of link descriptors 90 * @controller_id: which DMA controller (0, 1, ...) 91 * @channel_id: which DMA channel on the controller (0, 1, 2, ...) 92 * @dma_channel: pointer to the DMA channel's registers 93 * @irq: IRQ for this DMA channel 94 * @substream: pointer to the substream object, needed by the ISR 95 * @ssi_sxx_phys: bus address of the STX or SRX register to use 96 * @ld_buf_phys: physical address of the LD buffer 97 * @current_link: index into link[] of the link currently being processed 98 * @dma_buf_phys: physical address of the DMA buffer 99 * @dma_buf_next: physical address of the next period to process 100 * @dma_buf_end: physical address of the byte after the end of the DMA 101 * @buffer period_size: the size of a single period 102 * @num_periods: the number of periods in the DMA buffer 103 */ 104 struct fsl_dma_private { 105 struct fsl_dma_link_descriptor link[NUM_DMA_LINKS]; 106 unsigned int controller_id; 107 unsigned int channel_id; 108 struct ccsr_dma_channel __iomem *dma_channel; 109 unsigned int irq; 110 struct snd_pcm_substream *substream; 111 dma_addr_t ssi_sxx_phys; 112 dma_addr_t ld_buf_phys; 113 unsigned int current_link; 114 dma_addr_t dma_buf_phys; 115 dma_addr_t dma_buf_next; 116 dma_addr_t dma_buf_end; 117 size_t period_size; 118 unsigned int num_periods; 119 }; 120 121 /** 122 * fsl_dma_hardare: define characteristics of the PCM hardware. 123 * 124 * The PCM hardware is the Freescale DMA controller. This structure defines 125 * the capabilities of that hardware. 126 * 127 * Since the sampling rate and data format are not controlled by the DMA 128 * controller, we specify no limits for those values. The only exception is 129 * period_bytes_min, which is set to a reasonably low value to prevent the 130 * DMA controller from generating too many interrupts per second. 131 * 132 * Since each link descriptor has a 32-bit byte count field, we set 133 * period_bytes_max to the largest 32-bit number. We also have no maximum 134 * number of periods. 135 * 136 * Note that we specify SNDRV_PCM_INFO_JOINT_DUPLEX here, but only because a 137 * limitation in the SSI driver requires the sample rates for playback and 138 * capture to be the same. 139 */ 140 static const struct snd_pcm_hardware fsl_dma_hardware = { 141 142 .info = SNDRV_PCM_INFO_INTERLEAVED | 143 SNDRV_PCM_INFO_MMAP | 144 SNDRV_PCM_INFO_MMAP_VALID | 145 SNDRV_PCM_INFO_JOINT_DUPLEX | 146 SNDRV_PCM_INFO_PAUSE, 147 .formats = FSLDMA_PCM_FORMATS, 148 .rates = FSLDMA_PCM_RATES, 149 .rate_min = 5512, 150 .rate_max = 192000, 151 .period_bytes_min = 512, /* A reasonable limit */ 152 .period_bytes_max = (u32) -1, 153 .periods_min = NUM_DMA_LINKS, 154 .periods_max = (unsigned int) -1, 155 .buffer_bytes_max = 128 * 1024, /* A reasonable limit */ 156 }; 157 158 /** 159 * fsl_dma_abort_stream: tell ALSA that the DMA transfer has aborted 160 * 161 * This function should be called by the ISR whenever the DMA controller 162 * halts data transfer. 163 */ 164 static void fsl_dma_abort_stream(struct snd_pcm_substream *substream) 165 { 166 unsigned long flags; 167 168 snd_pcm_stream_lock_irqsave(substream, flags); 169 170 if (snd_pcm_running(substream)) 171 snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN); 172 173 snd_pcm_stream_unlock_irqrestore(substream, flags); 174 } 175 176 /** 177 * fsl_dma_update_pointers - update LD pointers to point to the next period 178 * 179 * As each period is completed, this function changes the the link 180 * descriptor pointers for that period to point to the next period. 181 */ 182 static void fsl_dma_update_pointers(struct fsl_dma_private *dma_private) 183 { 184 struct fsl_dma_link_descriptor *link = 185 &dma_private->link[dma_private->current_link]; 186 187 /* Update our link descriptors to point to the next period */ 188 if (dma_private->substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 189 link->source_addr = 190 cpu_to_be32(dma_private->dma_buf_next); 191 else 192 link->dest_addr = 193 cpu_to_be32(dma_private->dma_buf_next); 194 195 /* Update our variables for next time */ 196 dma_private->dma_buf_next += dma_private->period_size; 197 198 if (dma_private->dma_buf_next >= dma_private->dma_buf_end) 199 dma_private->dma_buf_next = dma_private->dma_buf_phys; 200 201 if (++dma_private->current_link >= NUM_DMA_LINKS) 202 dma_private->current_link = 0; 203 } 204 205 /** 206 * fsl_dma_isr: interrupt handler for the DMA controller 207 * 208 * @irq: IRQ of the DMA channel 209 * @dev_id: pointer to the dma_private structure for this DMA channel 210 */ 211 static irqreturn_t fsl_dma_isr(int irq, void *dev_id) 212 { 213 struct fsl_dma_private *dma_private = dev_id; 214 struct ccsr_dma_channel __iomem *dma_channel = dma_private->dma_channel; 215 irqreturn_t ret = IRQ_NONE; 216 u32 sr, sr2 = 0; 217 218 /* We got an interrupt, so read the status register to see what we 219 were interrupted for. 220 */ 221 sr = in_be32(&dma_channel->sr); 222 223 if (sr & CCSR_DMA_SR_TE) { 224 dev_err(dma_private->substream->pcm->card->dev, 225 "DMA transmit error (controller=%u channel=%u irq=%u\n", 226 dma_private->controller_id, 227 dma_private->channel_id, irq); 228 fsl_dma_abort_stream(dma_private->substream); 229 sr2 |= CCSR_DMA_SR_TE; 230 ret = IRQ_HANDLED; 231 } 232 233 if (sr & CCSR_DMA_SR_CH) 234 ret = IRQ_HANDLED; 235 236 if (sr & CCSR_DMA_SR_PE) { 237 dev_err(dma_private->substream->pcm->card->dev, 238 "DMA%u programming error (channel=%u irq=%u)\n", 239 dma_private->controller_id, 240 dma_private->channel_id, irq); 241 fsl_dma_abort_stream(dma_private->substream); 242 sr2 |= CCSR_DMA_SR_PE; 243 ret = IRQ_HANDLED; 244 } 245 246 if (sr & CCSR_DMA_SR_EOLNI) { 247 sr2 |= CCSR_DMA_SR_EOLNI; 248 ret = IRQ_HANDLED; 249 } 250 251 if (sr & CCSR_DMA_SR_CB) 252 ret = IRQ_HANDLED; 253 254 if (sr & CCSR_DMA_SR_EOSI) { 255 struct snd_pcm_substream *substream = dma_private->substream; 256 257 /* Tell ALSA we completed a period. */ 258 snd_pcm_period_elapsed(substream); 259 260 /* 261 * Update our link descriptors to point to the next period. We 262 * only need to do this if the number of periods is not equal to 263 * the number of links. 264 */ 265 if (dma_private->num_periods != NUM_DMA_LINKS) 266 fsl_dma_update_pointers(dma_private); 267 268 sr2 |= CCSR_DMA_SR_EOSI; 269 ret = IRQ_HANDLED; 270 } 271 272 if (sr & CCSR_DMA_SR_EOLSI) { 273 sr2 |= CCSR_DMA_SR_EOLSI; 274 ret = IRQ_HANDLED; 275 } 276 277 /* Clear the bits that we set */ 278 if (sr2) 279 out_be32(&dma_channel->sr, sr2); 280 281 return ret; 282 } 283 284 /** 285 * fsl_dma_new: initialize this PCM driver. 286 * 287 * This function is called when the codec driver calls snd_soc_new_pcms(), 288 * once for each .dai_link in the machine driver's snd_soc_card 289 * structure. 290 */ 291 static int fsl_dma_new(struct snd_card *card, struct snd_soc_dai *dai, 292 struct snd_pcm *pcm) 293 { 294 static u64 fsl_dma_dmamask = DMA_BIT_MASK(32); 295 int ret; 296 297 if (!card->dev->dma_mask) 298 card->dev->dma_mask = &fsl_dma_dmamask; 299 300 if (!card->dev->coherent_dma_mask) 301 card->dev->coherent_dma_mask = fsl_dma_dmamask; 302 303 ret = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, card->dev, 304 fsl_dma_hardware.buffer_bytes_max, 305 &pcm->streams[0].substream->dma_buffer); 306 if (ret) { 307 dev_err(card->dev, 308 "Can't allocate playback DMA buffer (size=%u)\n", 309 fsl_dma_hardware.buffer_bytes_max); 310 return -ENOMEM; 311 } 312 313 ret = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, card->dev, 314 fsl_dma_hardware.buffer_bytes_max, 315 &pcm->streams[1].substream->dma_buffer); 316 if (ret) { 317 snd_dma_free_pages(&pcm->streams[0].substream->dma_buffer); 318 dev_err(card->dev, 319 "Can't allocate capture DMA buffer (size=%u)\n", 320 fsl_dma_hardware.buffer_bytes_max); 321 return -ENOMEM; 322 } 323 324 return 0; 325 } 326 327 /** 328 * fsl_dma_open: open a new substream. 329 * 330 * Each substream has its own DMA buffer. 331 * 332 * ALSA divides the DMA buffer into N periods. We create NUM_DMA_LINKS link 333 * descriptors that ping-pong from one period to the next. For example, if 334 * there are six periods and two link descriptors, this is how they look 335 * before playback starts: 336 * 337 * The last link descriptor 338 * ____________ points back to the first 339 * | | 340 * V | 341 * ___ ___ | 342 * | |->| |->| 343 * |___| |___| 344 * | | 345 * | | 346 * V V 347 * _________________________________________ 348 * | | | | | | | The DMA buffer is 349 * | | | | | | | divided into 6 parts 350 * |______|______|______|______|______|______| 351 * 352 * and here's how they look after the first period is finished playing: 353 * 354 * ____________ 355 * | | 356 * V | 357 * ___ ___ | 358 * | |->| |->| 359 * |___| |___| 360 * | | 361 * |______________ 362 * | | 363 * V V 364 * _________________________________________ 365 * | | | | | | | 366 * | | | | | | | 367 * |______|______|______|______|______|______| 368 * 369 * The first link descriptor now points to the third period. The DMA 370 * controller is currently playing the second period. When it finishes, it 371 * will jump back to the first descriptor and play the third period. 372 * 373 * There are four reasons we do this: 374 * 375 * 1. The only way to get the DMA controller to automatically restart the 376 * transfer when it gets to the end of the buffer is to use chaining 377 * mode. Basic direct mode doesn't offer that feature. 378 * 2. We need to receive an interrupt at the end of every period. The DMA 379 * controller can generate an interrupt at the end of every link transfer 380 * (aka segment). Making each period into a DMA segment will give us the 381 * interrupts we need. 382 * 3. By creating only two link descriptors, regardless of the number of 383 * periods, we do not need to reallocate the link descriptors if the 384 * number of periods changes. 385 * 4. All of the audio data is still stored in a single, contiguous DMA 386 * buffer, which is what ALSA expects. We're just dividing it into 387 * contiguous parts, and creating a link descriptor for each one. 388 */ 389 static int fsl_dma_open(struct snd_pcm_substream *substream) 390 { 391 struct snd_pcm_runtime *runtime = substream->runtime; 392 struct fsl_dma_private *dma_private; 393 struct ccsr_dma_channel __iomem *dma_channel; 394 dma_addr_t ld_buf_phys; 395 u64 temp_link; /* Pointer to next link descriptor */ 396 u32 mr; 397 unsigned int channel; 398 int ret = 0; 399 unsigned int i; 400 401 /* 402 * Reject any DMA buffer whose size is not a multiple of the period 403 * size. We need to make sure that the DMA buffer can be evenly divided 404 * into periods. 405 */ 406 ret = snd_pcm_hw_constraint_integer(runtime, 407 SNDRV_PCM_HW_PARAM_PERIODS); 408 if (ret < 0) { 409 dev_err(substream->pcm->card->dev, "invalid buffer size\n"); 410 return ret; 411 } 412 413 channel = substream->stream == SNDRV_PCM_STREAM_PLAYBACK ? 0 : 1; 414 415 if (dma_global_data.assigned[channel]) { 416 dev_err(substream->pcm->card->dev, 417 "DMA channel already assigned\n"); 418 return -EBUSY; 419 } 420 421 dma_private = dma_alloc_coherent(substream->pcm->card->dev, 422 sizeof(struct fsl_dma_private), &ld_buf_phys, GFP_KERNEL); 423 if (!dma_private) { 424 dev_err(substream->pcm->card->dev, 425 "can't allocate DMA private data\n"); 426 return -ENOMEM; 427 } 428 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 429 dma_private->ssi_sxx_phys = dma_global_data.ssi_stx_phys; 430 else 431 dma_private->ssi_sxx_phys = dma_global_data.ssi_srx_phys; 432 433 dma_private->dma_channel = dma_global_data.dma_channel[channel]; 434 dma_private->irq = dma_global_data.irq[channel]; 435 dma_private->substream = substream; 436 dma_private->ld_buf_phys = ld_buf_phys; 437 dma_private->dma_buf_phys = substream->dma_buffer.addr; 438 439 /* We only support one DMA controller for now */ 440 dma_private->controller_id = 0; 441 dma_private->channel_id = channel; 442 443 ret = request_irq(dma_private->irq, fsl_dma_isr, 0, "DMA", dma_private); 444 if (ret) { 445 dev_err(substream->pcm->card->dev, 446 "can't register ISR for IRQ %u (ret=%i)\n", 447 dma_private->irq, ret); 448 dma_free_coherent(substream->pcm->card->dev, 449 sizeof(struct fsl_dma_private), 450 dma_private, dma_private->ld_buf_phys); 451 return ret; 452 } 453 454 dma_global_data.assigned[channel] = 1; 455 456 snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer); 457 snd_soc_set_runtime_hwparams(substream, &fsl_dma_hardware); 458 runtime->private_data = dma_private; 459 460 /* Program the fixed DMA controller parameters */ 461 462 dma_channel = dma_private->dma_channel; 463 464 temp_link = dma_private->ld_buf_phys + 465 sizeof(struct fsl_dma_link_descriptor); 466 467 for (i = 0; i < NUM_DMA_LINKS; i++) { 468 dma_private->link[i].next = cpu_to_be64(temp_link); 469 470 temp_link += sizeof(struct fsl_dma_link_descriptor); 471 } 472 /* The last link descriptor points to the first */ 473 dma_private->link[i - 1].next = cpu_to_be64(dma_private->ld_buf_phys); 474 475 /* Tell the DMA controller where the first link descriptor is */ 476 out_be32(&dma_channel->clndar, 477 CCSR_DMA_CLNDAR_ADDR(dma_private->ld_buf_phys)); 478 out_be32(&dma_channel->eclndar, 479 CCSR_DMA_ECLNDAR_ADDR(dma_private->ld_buf_phys)); 480 481 /* The manual says the BCR must be clear before enabling EMP */ 482 out_be32(&dma_channel->bcr, 0); 483 484 /* 485 * Program the mode register for interrupts, external master control, 486 * and source/destination hold. Also clear the Channel Abort bit. 487 */ 488 mr = in_be32(&dma_channel->mr) & 489 ~(CCSR_DMA_MR_CA | CCSR_DMA_MR_DAHE | CCSR_DMA_MR_SAHE); 490 491 /* 492 * We want External Master Start and External Master Pause enabled, 493 * because the SSI is controlling the DMA controller. We want the DMA 494 * controller to be set up in advance, and then we signal only the SSI 495 * to start transferring. 496 * 497 * We want End-Of-Segment Interrupts enabled, because this will generate 498 * an interrupt at the end of each segment (each link descriptor 499 * represents one segment). Each DMA segment is the same thing as an 500 * ALSA period, so this is how we get an interrupt at the end of every 501 * period. 502 * 503 * We want Error Interrupt enabled, so that we can get an error if 504 * the DMA controller is mis-programmed somehow. 505 */ 506 mr |= CCSR_DMA_MR_EOSIE | CCSR_DMA_MR_EIE | CCSR_DMA_MR_EMP_EN | 507 CCSR_DMA_MR_EMS_EN; 508 509 /* For playback, we want the destination address to be held. For 510 capture, set the source address to be held. */ 511 mr |= (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) ? 512 CCSR_DMA_MR_DAHE : CCSR_DMA_MR_SAHE; 513 514 out_be32(&dma_channel->mr, mr); 515 516 return 0; 517 } 518 519 /** 520 * fsl_dma_hw_params: continue initializing the DMA links 521 * 522 * This function obtains hardware parameters about the opened stream and 523 * programs the DMA controller accordingly. 524 * 525 * One drawback of big-endian is that when copying integers of different 526 * sizes to a fixed-sized register, the address to which the integer must be 527 * copied is dependent on the size of the integer. 528 * 529 * For example, if P is the address of a 32-bit register, and X is a 32-bit 530 * integer, then X should be copied to address P. However, if X is a 16-bit 531 * integer, then it should be copied to P+2. If X is an 8-bit register, 532 * then it should be copied to P+3. 533 * 534 * So for playback of 8-bit samples, the DMA controller must transfer single 535 * bytes from the DMA buffer to the last byte of the STX0 register, i.e. 536 * offset by 3 bytes. For 16-bit samples, the offset is two bytes. 537 * 538 * For 24-bit samples, the offset is 1 byte. However, the DMA controller 539 * does not support 3-byte copies (the DAHTS register supports only 1, 2, 4, 540 * and 8 bytes at a time). So we do not support packed 24-bit samples. 541 * 24-bit data must be padded to 32 bits. 542 */ 543 static int fsl_dma_hw_params(struct snd_pcm_substream *substream, 544 struct snd_pcm_hw_params *hw_params) 545 { 546 struct snd_pcm_runtime *runtime = substream->runtime; 547 struct fsl_dma_private *dma_private = runtime->private_data; 548 549 /* Number of bits per sample */ 550 unsigned int sample_size = 551 snd_pcm_format_physical_width(params_format(hw_params)); 552 553 /* Number of bytes per frame */ 554 unsigned int frame_size = 2 * (sample_size / 8); 555 556 /* Bus address of SSI STX register */ 557 dma_addr_t ssi_sxx_phys = dma_private->ssi_sxx_phys; 558 559 /* Size of the DMA buffer, in bytes */ 560 size_t buffer_size = params_buffer_bytes(hw_params); 561 562 /* Number of bytes per period */ 563 size_t period_size = params_period_bytes(hw_params); 564 565 /* Pointer to next period */ 566 dma_addr_t temp_addr = substream->dma_buffer.addr; 567 568 /* Pointer to DMA controller */ 569 struct ccsr_dma_channel __iomem *dma_channel = dma_private->dma_channel; 570 571 u32 mr; /* DMA Mode Register */ 572 573 unsigned int i; 574 575 /* Initialize our DMA tracking variables */ 576 dma_private->period_size = period_size; 577 dma_private->num_periods = params_periods(hw_params); 578 dma_private->dma_buf_end = dma_private->dma_buf_phys + buffer_size; 579 dma_private->dma_buf_next = dma_private->dma_buf_phys + 580 (NUM_DMA_LINKS * period_size); 581 582 if (dma_private->dma_buf_next >= dma_private->dma_buf_end) 583 /* This happens if the number of periods == NUM_DMA_LINKS */ 584 dma_private->dma_buf_next = dma_private->dma_buf_phys; 585 586 mr = in_be32(&dma_channel->mr) & ~(CCSR_DMA_MR_BWC_MASK | 587 CCSR_DMA_MR_SAHTS_MASK | CCSR_DMA_MR_DAHTS_MASK); 588 589 /* Due to a quirk of the SSI's STX register, the target address 590 * for the DMA operations depends on the sample size. So we calculate 591 * that offset here. While we're at it, also tell the DMA controller 592 * how much data to transfer per sample. 593 */ 594 switch (sample_size) { 595 case 8: 596 mr |= CCSR_DMA_MR_DAHTS_1 | CCSR_DMA_MR_SAHTS_1; 597 ssi_sxx_phys += 3; 598 break; 599 case 16: 600 mr |= CCSR_DMA_MR_DAHTS_2 | CCSR_DMA_MR_SAHTS_2; 601 ssi_sxx_phys += 2; 602 break; 603 case 32: 604 mr |= CCSR_DMA_MR_DAHTS_4 | CCSR_DMA_MR_SAHTS_4; 605 break; 606 default: 607 /* We should never get here */ 608 dev_err(substream->pcm->card->dev, 609 "unsupported sample size %u\n", sample_size); 610 return -EINVAL; 611 } 612 613 /* 614 * BWC should always be a multiple of the frame size. BWC determines 615 * how many bytes are sent/received before the DMA controller checks the 616 * SSI to see if it needs to stop. For playback, the transmit FIFO can 617 * hold three frames, so we want to send two frames at a time. For 618 * capture, the receive FIFO is triggered when it contains one frame, so 619 * we want to receive one frame at a time. 620 */ 621 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 622 mr |= CCSR_DMA_MR_BWC(2 * frame_size); 623 else 624 mr |= CCSR_DMA_MR_BWC(frame_size); 625 626 out_be32(&dma_channel->mr, mr); 627 628 for (i = 0; i < NUM_DMA_LINKS; i++) { 629 struct fsl_dma_link_descriptor *link = &dma_private->link[i]; 630 631 link->count = cpu_to_be32(period_size); 632 633 /* Even though the DMA controller supports 36-bit addressing, 634 * for simplicity we allow only 32-bit addresses for the audio 635 * buffer itself. This was enforced in fsl_dma_new() with the 636 * DMA mask. 637 * 638 * The snoop bit tells the DMA controller whether it should tell 639 * the ECM to snoop during a read or write to an address. For 640 * audio, we use DMA to transfer data between memory and an I/O 641 * device (the SSI's STX0 or SRX0 register). Snooping is only 642 * needed if there is a cache, so we need to snoop memory 643 * addresses only. For playback, that means we snoop the source 644 * but not the destination. For capture, we snoop the 645 * destination but not the source. 646 * 647 * Note that failing to snoop properly is unlikely to cause 648 * cache incoherency if the period size is larger than the 649 * size of L1 cache. This is because filling in one period will 650 * flush out the data for the previous period. So if you 651 * increased period_bytes_min to a large enough size, you might 652 * get more performance by not snooping, and you'll still be 653 * okay. 654 */ 655 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) { 656 link->source_addr = cpu_to_be32(temp_addr); 657 link->source_attr = cpu_to_be32(CCSR_DMA_ATR_SNOOP); 658 659 link->dest_addr = cpu_to_be32(ssi_sxx_phys); 660 link->dest_attr = cpu_to_be32(CCSR_DMA_ATR_NOSNOOP); 661 } else { 662 link->source_addr = cpu_to_be32(ssi_sxx_phys); 663 link->source_attr = cpu_to_be32(CCSR_DMA_ATR_NOSNOOP); 664 665 link->dest_addr = cpu_to_be32(temp_addr); 666 link->dest_attr = cpu_to_be32(CCSR_DMA_ATR_SNOOP); 667 } 668 669 temp_addr += period_size; 670 } 671 672 return 0; 673 } 674 675 /** 676 * fsl_dma_pointer: determine the current position of the DMA transfer 677 * 678 * This function is called by ALSA when ALSA wants to know where in the 679 * stream buffer the hardware currently is. 680 * 681 * For playback, the SAR register contains the physical address of the most 682 * recent DMA transfer. For capture, the value is in the DAR register. 683 * 684 * The base address of the buffer is stored in the source_addr field of the 685 * first link descriptor. 686 */ 687 static snd_pcm_uframes_t fsl_dma_pointer(struct snd_pcm_substream *substream) 688 { 689 struct snd_pcm_runtime *runtime = substream->runtime; 690 struct fsl_dma_private *dma_private = runtime->private_data; 691 struct ccsr_dma_channel __iomem *dma_channel = dma_private->dma_channel; 692 dma_addr_t position; 693 snd_pcm_uframes_t frames; 694 695 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 696 position = in_be32(&dma_channel->sar); 697 else 698 position = in_be32(&dma_channel->dar); 699 700 /* 701 * When capture is started, the SSI immediately starts to fill its FIFO. 702 * This means that the DMA controller is not started until the FIFO is 703 * full. However, ALSA calls this function before that happens, when 704 * MR.DAR is still zero. In this case, just return zero to indicate 705 * that nothing has been received yet. 706 */ 707 if (!position) 708 return 0; 709 710 if ((position < dma_private->dma_buf_phys) || 711 (position > dma_private->dma_buf_end)) { 712 dev_err(substream->pcm->card->dev, 713 "dma pointer is out of range, halting stream\n"); 714 return SNDRV_PCM_POS_XRUN; 715 } 716 717 frames = bytes_to_frames(runtime, position - dma_private->dma_buf_phys); 718 719 /* 720 * If the current address is just past the end of the buffer, wrap it 721 * around. 722 */ 723 if (frames == runtime->buffer_size) 724 frames = 0; 725 726 return frames; 727 } 728 729 /** 730 * fsl_dma_hw_free: release resources allocated in fsl_dma_hw_params() 731 * 732 * Release the resources allocated in fsl_dma_hw_params() and de-program the 733 * registers. 734 * 735 * This function can be called multiple times. 736 */ 737 static int fsl_dma_hw_free(struct snd_pcm_substream *substream) 738 { 739 struct snd_pcm_runtime *runtime = substream->runtime; 740 struct fsl_dma_private *dma_private = runtime->private_data; 741 742 if (dma_private) { 743 struct ccsr_dma_channel __iomem *dma_channel; 744 745 dma_channel = dma_private->dma_channel; 746 747 /* Stop the DMA */ 748 out_be32(&dma_channel->mr, CCSR_DMA_MR_CA); 749 out_be32(&dma_channel->mr, 0); 750 751 /* Reset all the other registers */ 752 out_be32(&dma_channel->sr, -1); 753 out_be32(&dma_channel->clndar, 0); 754 out_be32(&dma_channel->eclndar, 0); 755 out_be32(&dma_channel->satr, 0); 756 out_be32(&dma_channel->sar, 0); 757 out_be32(&dma_channel->datr, 0); 758 out_be32(&dma_channel->dar, 0); 759 out_be32(&dma_channel->bcr, 0); 760 out_be32(&dma_channel->nlndar, 0); 761 out_be32(&dma_channel->enlndar, 0); 762 } 763 764 return 0; 765 } 766 767 /** 768 * fsl_dma_close: close the stream. 769 */ 770 static int fsl_dma_close(struct snd_pcm_substream *substream) 771 { 772 struct snd_pcm_runtime *runtime = substream->runtime; 773 struct fsl_dma_private *dma_private = runtime->private_data; 774 int dir = substream->stream == SNDRV_PCM_STREAM_PLAYBACK ? 0 : 1; 775 776 if (dma_private) { 777 if (dma_private->irq) 778 free_irq(dma_private->irq, dma_private); 779 780 if (dma_private->ld_buf_phys) { 781 dma_unmap_single(substream->pcm->card->dev, 782 dma_private->ld_buf_phys, 783 sizeof(dma_private->link), DMA_TO_DEVICE); 784 } 785 786 /* Deallocate the fsl_dma_private structure */ 787 dma_free_coherent(substream->pcm->card->dev, 788 sizeof(struct fsl_dma_private), 789 dma_private, dma_private->ld_buf_phys); 790 substream->runtime->private_data = NULL; 791 } 792 793 dma_global_data.assigned[dir] = 0; 794 795 return 0; 796 } 797 798 /* 799 * Remove this PCM driver. 800 */ 801 static void fsl_dma_free_dma_buffers(struct snd_pcm *pcm) 802 { 803 struct snd_pcm_substream *substream; 804 unsigned int i; 805 806 for (i = 0; i < ARRAY_SIZE(pcm->streams); i++) { 807 substream = pcm->streams[i].substream; 808 if (substream) { 809 snd_dma_free_pages(&substream->dma_buffer); 810 substream->dma_buffer.area = NULL; 811 substream->dma_buffer.addr = 0; 812 } 813 } 814 } 815 816 static struct snd_pcm_ops fsl_dma_ops = { 817 .open = fsl_dma_open, 818 .close = fsl_dma_close, 819 .ioctl = snd_pcm_lib_ioctl, 820 .hw_params = fsl_dma_hw_params, 821 .hw_free = fsl_dma_hw_free, 822 .pointer = fsl_dma_pointer, 823 }; 824 825 struct snd_soc_platform fsl_soc_platform = { 826 .name = "fsl-dma", 827 .pcm_ops = &fsl_dma_ops, 828 .pcm_new = fsl_dma_new, 829 .pcm_free = fsl_dma_free_dma_buffers, 830 }; 831 EXPORT_SYMBOL_GPL(fsl_soc_platform); 832 833 /** 834 * fsl_dma_configure: store the DMA parameters from the fabric driver. 835 * 836 * This function is called by the ASoC fabric driver to give us the DMA and 837 * SSI channel information. 838 * 839 * Unfortunately, ASoC V1 does make it possible to determine the DMA/SSI 840 * data when a substream is created, so for now we need to store this data 841 * into a global variable. This means that we can only support one DMA 842 * controller, and hence only one SSI. 843 */ 844 int fsl_dma_configure(struct fsl_dma_info *dma_info) 845 { 846 static int initialized; 847 848 /* We only support one DMA controller for now */ 849 if (initialized) 850 return 0; 851 852 dma_global_data.ssi_stx_phys = dma_info->ssi_stx_phys; 853 dma_global_data.ssi_srx_phys = dma_info->ssi_srx_phys; 854 dma_global_data.dma_channel[0] = dma_info->dma_channel[0]; 855 dma_global_data.dma_channel[1] = dma_info->dma_channel[1]; 856 dma_global_data.irq[0] = dma_info->dma_irq[0]; 857 dma_global_data.irq[1] = dma_info->dma_irq[1]; 858 dma_global_data.assigned[0] = 0; 859 dma_global_data.assigned[1] = 0; 860 861 initialized = 1; 862 return 1; 863 } 864 EXPORT_SYMBOL_GPL(fsl_dma_configure); 865 866 static int __init fsl_soc_platform_init(void) 867 { 868 return snd_soc_register_platform(&fsl_soc_platform); 869 } 870 module_init(fsl_soc_platform_init); 871 872 static void __exit fsl_soc_platform_exit(void) 873 { 874 snd_soc_unregister_platform(&fsl_soc_platform); 875 } 876 module_exit(fsl_soc_platform_exit); 877 878 MODULE_AUTHOR("Timur Tabi <timur@freescale.com>"); 879 MODULE_DESCRIPTION("Freescale Elo DMA ASoC PCM module"); 880 MODULE_LICENSE("GPL"); 881