arch/arm/mach-imx/dma.c

   1 /*
   2  *  linux/arch/arm/mach-imx/dma.c
   3  *
   4  *  imx DMA registration and IRQ dispatching
   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 version 2 as
   8  *  published by the Free Software Foundation.
   9  *
  10  *  2004-03-03 Sascha Hauer <sascha@saschahauer.de>
  11  *             initial version heavily inspired by
  12  *             linux/arch/arm/mach-pxa/dma.c
  13  *
  14  *  2005-04-17 Pavel Pisa <pisa@cmp.felk.cvut.cz>
  15  *             Changed to support scatter gather DMA
  16  *             by taking Russell's code from RiscPC
  17  *
  18  *  2006-05-31 Pavel Pisa <pisa@cmp.felk.cvut.cz>
  19  *             Corrected error handling code.
  20  *
  21  */
  22
  23 #undef DEBUG
  24
  25 #include <linux/module.h>
  26 #include <linux/init.h>
  27 #include <linux/kernel.h>
  28 #include <linux/interrupt.h>
  29 #include <linux/errno.h>
  30
  31 #include <asm/system.h>
  32 #include <asm/irq.h>
  33 #include <asm/hardware.h>
  34 #include <asm/dma.h>
  35 #include <asm/arch/imx-dma.h>
  36
  37 struct imx_dma_channel imx_dma_channels[IMX_DMA_CHANNELS];
  38
  39 /*
  40  * imx_dma_sg_next - prepare next chunk for scatter-gather DMA emulation
  41  * @dma_ch: i.MX DMA channel number
  42  * @lastcount: number of bytes transferred during last transfer
  43  *
  44  * Functions prepares DMA controller for next sg data chunk transfer.
  45  * The @lastcount argument informs function about number of bytes transferred
  46  * during last block. Zero value can be used for @lastcount to setup DMA
  47  * for the first chunk.
  48  */
  49 static inline int imx_dma_sg_next(imx_dmach_t dma_ch, unsigned int lastcount)
  50 {
  51         struct imx_dma_channel *imxdma = &imx_dma_channels[dma_ch];
  52         unsigned int nextcount;
  53         unsigned int nextaddr;
  54
  55         if (!imxdma->name) {
  56                 printk(KERN_CRIT "%s: called for  not allocated channel %d\n",
  57                        __func__, dma_ch);
  58                 return 0;
  59         }
  60
  61         imxdma->resbytes -= lastcount;
  62
  63         if (!imxdma->sg) {
  64                 pr_debug("imxdma%d: no sg data\n", dma_ch);
  65                 return 0;
  66         }
  67
  68         imxdma->sgbc += lastcount;
  69         if ((imxdma->sgbc >= imxdma->sg->length) || !imxdma->resbytes) {
  70                 if ((imxdma->sgcount <= 1) || !imxdma->resbytes) {
  71                         pr_debug("imxdma%d: sg transfer limit reached\n",
  72                                  dma_ch);
  73                         imxdma->sgcount=0;
  74                         imxdma->sg = NULL;
  75                         return 0;
  76                 } else {
  77                         imxdma->sgcount--;
  78                         imxdma->sg++;
  79                         imxdma->sgbc = 0;
  80                 }
  81         }
  82         nextcount = imxdma->sg->length - imxdma->sgbc;
  83         nextaddr = imxdma->sg->dma_address + imxdma->sgbc;
  84
  85         if(imxdma->resbytes < nextcount)
  86                 nextcount = imxdma->resbytes;
  87
  88         if ((imxdma->dma_mode & DMA_MODE_MASK) == DMA_MODE_READ)
  89                 DAR(dma_ch) = nextaddr;
  90         else
  91                 SAR(dma_ch) = nextaddr;
  92
  93         CNTR(dma_ch) = nextcount;
  94         pr_debug("imxdma%d: next sg chunk dst 0x%08x, src 0x%08x, size 0x%08x\n",
  95                  dma_ch, DAR(dma_ch), SAR(dma_ch), CNTR(dma_ch));
  96
  97         return nextcount;
  98 }
  99
 100 /*
 101  * imx_dma_setup_sg_base - scatter-gather DMA emulation
 102  * @dma_ch: i.MX DMA channel number
 103  * @sg: pointer to the scatter-gather list/vector
 104  * @sgcount: scatter-gather list hungs count
 105  *
 106  * Functions sets up i.MX DMA state for emulated scatter-gather transfer
 107  * and sets up channel registers to be ready for the first chunk
 108  */
 109 static int
 110 imx_dma_setup_sg_base(imx_dmach_t dma_ch,
 111                       struct scatterlist *sg, unsigned int sgcount)
 112 {
 113         struct imx_dma_channel *imxdma = &imx_dma_channels[dma_ch];
 114
 115         imxdma->sg = sg;
 116         imxdma->sgcount = sgcount;
 117         imxdma->sgbc = 0;
 118         return imx_dma_sg_next(dma_ch, 0);
 119 }
 120
 121 /**
 122  * imx_dma_setup_single - setup i.MX DMA channel for linear memory to/from device transfer
 123  * @dma_ch: i.MX DMA channel number
 124  * @dma_address: the DMA/physical memory address of the linear data block
 125  *              to transfer
 126  * @dma_length: length of the data block in bytes
 127  * @dev_addr: physical device port address
 128  * @dmamode: DMA transfer mode, %DMA_MODE_READ from the device to the memory
 129  *           or %DMA_MODE_WRITE from memory to the device
 130  *
 131  * The function setups DMA channel source and destination addresses for transfer
 132  * specified by provided parameters. The scatter-gather emulation is disabled,
 133  * because linear data block
 134  * form the physical address range is transferred.
 135  * Return value: if incorrect parameters are provided -%EINVAL.
 136  *              Zero indicates success.
 137  */
 138 int
 139 imx_dma_setup_single(imx_dmach_t dma_ch, dma_addr_t dma_address,
 140                      unsigned int dma_length, unsigned int dev_addr,
 141                      dmamode_t dmamode)
 142 {
 143         struct imx_dma_channel *imxdma = &imx_dma_channels[dma_ch];
 144
 145         imxdma->sg = NULL;
 146         imxdma->sgcount = 0;
 147         imxdma->dma_mode = dmamode;
 148         imxdma->resbytes = dma_length;
 149
 150         if (!dma_address) {
 151                 printk(KERN_ERR "imxdma%d: imx_dma_setup_single null address\n",
 152                        dma_ch);
 153                 return -EINVAL;
 154         }
 155
 156         if (!dma_length) {
 157                 printk(KERN_ERR "imxdma%d: imx_dma_setup_single zero length\n",
 158                        dma_ch);
 159                 return -EINVAL;
 160         }
 161
 162         if ((dmamode & DMA_MODE_MASK) == DMA_MODE_READ) {
 163                 pr_debug("imxdma%d: mx_dma_setup_single2dev dma_addressg=0x%08x dma_length=%d dev_addr=0x%08x for read\n",
 164                         dma_ch, (unsigned int)dma_address, dma_length,
 165                         dev_addr);
 166                 SAR(dma_ch) = dev_addr;
 167                 DAR(dma_ch) = (unsigned int)dma_address;
 168         } else if ((dmamode & DMA_MODE_MASK) == DMA_MODE_WRITE) {
 169                 pr_debug("imxdma%d: mx_dma_setup_single2dev dma_addressg=0x%08x dma_length=%d dev_addr=0x%08x for write\n",
 170                         dma_ch, (unsigned int)dma_address, dma_length,
 171                         dev_addr);
 172                 SAR(dma_ch) = (unsigned int)dma_address;
 173                 DAR(dma_ch) = dev_addr;
 174         } else {
 175                 printk(KERN_ERR "imxdma%d: imx_dma_setup_single bad dmamode\n",
 176                        dma_ch);
 177                 return -EINVAL;
 178         }
 179
 180         CNTR(dma_ch) = dma_length;
 181
 182         return 0;
 183 }
 184
 185 /**
 186  * imx_dma_setup_sg - setup i.MX DMA channel SG list to/from device transfer
 187  * @dma_ch: i.MX DMA channel number
 188  * @sg: pointer to the scatter-gather list/vector
 189  * @sgcount: scatter-gather list hungs count
 190  * @dma_length: total length of the transfer request in bytes
 191  * @dev_addr: physical device port address
 192  * @dmamode: DMA transfer mode, %DMA_MODE_READ from the device to the memory
 193  *           or %DMA_MODE_WRITE from memory to the device
 194  *
 195  * The function sets up DMA channel state and registers to be ready for transfer
 196  * specified by provided parameters. The scatter-gather emulation is set up
 197  * according to the parameters.
 198  *
 199  * The full preparation of the transfer requires setup of more register
 200  * by the caller before imx_dma_enable() can be called.
 201  *
 202  * %BLR(dma_ch) holds transfer burst length in bytes, 0 means 64 bytes
 203  *
 204  * %RSSR(dma_ch) has to be set to the DMA request line source %DMA_REQ_xxx
 205  *
 206  * %CCR(dma_ch) has to specify transfer parameters, the next settings is typical
 207  * for linear or simple scatter-gather transfers if %DMA_MODE_READ is specified
 208  *
 209  * %CCR_DMOD_LINEAR | %CCR_DSIZ_32 | %CCR_SMOD_FIFO | %CCR_SSIZ_x
 210  *
 211  * The typical setup for %DMA_MODE_WRITE is specified by next options combination
 212  *
 213  * %CCR_SMOD_LINEAR | %CCR_SSIZ_32 | %CCR_DMOD_FIFO | %CCR_DSIZ_x
 214  *
 215  * Be careful here and do not mistakenly mix source and target device
 216  * port sizes constants, they are really different:
 217  * %CCR_SSIZ_8, %CCR_SSIZ_16, %CCR_SSIZ_32,
 218  * %CCR_DSIZ_8, %CCR_DSIZ_16, %CCR_DSIZ_32
 219  *
 220  * Return value: if incorrect parameters are provided -%EINVAL.
 221  * Zero indicates success.
 222  */
 223 int
 224 imx_dma_setup_sg(imx_dmach_t dma_ch,
 225                  struct scatterlist *sg, unsigned int sgcount, unsigned int dma_length,
 226                  unsigned int dev_addr, dmamode_t dmamode)
 227 {
 228         int res;
 229         struct imx_dma_channel *imxdma = &imx_dma_channels[dma_ch];
 230
 231         imxdma->sg = NULL;
 232         imxdma->sgcount = 0;
 233         imxdma->dma_mode = dmamode;
 234         imxdma->resbytes = dma_length;
 235
 236         if (!sg || !sgcount) {
 237                 printk(KERN_ERR "imxdma%d: imx_dma_setup_sg epty sg list\n",
 238                        dma_ch);
 239                 return -EINVAL;
 240         }
 241
 242         if (!sg->length) {
 243                 printk(KERN_ERR "imxdma%d: imx_dma_setup_sg zero length\n",
 244                        dma_ch);
 245                 return -EINVAL;
 246         }
 247
 248         if ((dmamode & DMA_MODE_MASK) == DMA_MODE_READ) {
 249                 pr_debug("imxdma%d: mx_dma_setup_sg2dev sg=%p sgcount=%d total length=%d dev_addr=0x%08x for read\n",
 250                         dma_ch, sg, sgcount, dma_length, dev_addr);
 251                 SAR(dma_ch) = dev_addr;
 252         } else if ((dmamode & DMA_MODE_MASK) == DMA_MODE_WRITE) {
 253                 pr_debug("imxdma%d: mx_dma_setup_sg2dev sg=%p sgcount=%d total length=%d dev_addr=0x%08x for write\n",
 254                         dma_ch, sg, sgcount, dma_length, dev_addr);
 255                 DAR(dma_ch) = dev_addr;
 256         } else {
 257                 printk(KERN_ERR "imxdma%d: imx_dma_setup_sg bad dmamode\n",
 258                        dma_ch);
 259                 return -EINVAL;
 260         }
 261
 262         res = imx_dma_setup_sg_base(dma_ch, sg, sgcount);
 263         if (res <= 0) {
 264                 printk(KERN_ERR "imxdma%d: no sg chunk ready\n", dma_ch);
 265                 return -EINVAL;
 266         }
 267
 268         return 0;
 269 }
 270
 271 /**
 272  * imx_dma_setup_handlers - setup i.MX DMA channel end and error notification handlers
 273  * @dma_ch: i.MX DMA channel number
 274  * @irq_handler: the pointer to the function called if the transfer
 275  *              ends successfully
 276  * @err_handler: the pointer to the function called if the premature
 277  *              end caused by error occurs
 278  * @data: user specified value to be passed to the handlers
 279  */
 280 int
 281 imx_dma_setup_handlers(imx_dmach_t dma_ch,
 282                        void (*irq_handler) (int, void *),
 283                        void (*err_handler) (int, void *, int),
 284                        void *data)
 285 {
 286         struct imx_dma_channel *imxdma = &imx_dma_channels[dma_ch];
 287         unsigned long flags;
 288
 289         if (!imxdma->name) {
 290                 printk(KERN_CRIT "%s: called for  not allocated channel %d\n",
 291                        __func__, dma_ch);
 292                 return -ENODEV;
 293         }
 294
 295         local_irq_save(flags);
 296         DISR = (1 << dma_ch);
 297         imxdma->irq_handler = irq_handler;
 298         imxdma->err_handler = err_handler;
 299         imxdma->data = data;
 300         local_irq_restore(flags);
 301         return 0;
 302 }
 303
 304 /**
 305  * imx_dma_enable - function to start i.MX DMA channel operation
 306  * @dma_ch: i.MX DMA channel number
 307  *
 308  * The channel has to be allocated by driver through imx_dma_request()
 309  * or imx_dma_request_by_prio() function.
 310  * The transfer parameters has to be set to the channel registers through
 311  * call of the imx_dma_setup_single() or imx_dma_setup_sg() function
 312  * and registers %BLR(dma_ch), %RSSR(dma_ch) and %CCR(dma_ch) has to
 313  * be set prior this function call by the channel user.
 314  */
 315 void imx_dma_enable(imx_dmach_t dma_ch)
 316 {
 317         struct imx_dma_channel *imxdma = &imx_dma_channels[dma_ch];
 318         unsigned long flags;
 319
 320         pr_debug("imxdma%d: imx_dma_enable\n", dma_ch);
 321
 322         if (!imxdma->name) {
 323                 printk(KERN_CRIT "%s: called for  not allocated channel %d\n",
 324                        __func__, dma_ch);
 325                 return;
 326         }
 327
 328         local_irq_save(flags);
 329         DISR = (1 << dma_ch);
 330         DIMR &= ~(1 << dma_ch);
 331         CCR(dma_ch) |= CCR_CEN;
 332         local_irq_restore(flags);
 333 }
 334
 335 /**
 336  * imx_dma_disable - stop, finish i.MX DMA channel operatin
 337  * @dma_ch: i.MX DMA channel number
 338  */
 339 void imx_dma_disable(imx_dmach_t dma_ch)
 340 {
 341         unsigned long flags;
 342
 343         pr_debug("imxdma%d: imx_dma_disable\n", dma_ch);
 344
 345         local_irq_save(flags);
 346         DIMR |= (1 << dma_ch);
 347         CCR(dma_ch) &= ~CCR_CEN;
 348         DISR = (1 << dma_ch);
 349         local_irq_restore(flags);
 350 }
 351
 352 /**
 353  * imx_dma_request - request/allocate specified channel number
 354  * @dma_ch: i.MX DMA channel number
 355  * @name: the driver/caller own non-%NULL identification
 356  */
 357 int imx_dma_request(imx_dmach_t dma_ch, const char *name)
 358 {
 359         struct imx_dma_channel *imxdma = &imx_dma_channels[dma_ch];
 360         unsigned long flags;
 361
 362         /* basic sanity checks */
 363         if (!name)
 364                 return -EINVAL;
 365
 366         if (dma_ch >= IMX_DMA_CHANNELS) {
 367                 printk(KERN_CRIT "%s: called for  non-existed channel %d\n",
 368                        __func__, dma_ch);
 369                 return -EINVAL;
 370         }
 371
 372         local_irq_save(flags);
 373         if (imxdma->name) {
 374                 local_irq_restore(flags);
 375                 return -ENODEV;
 376         }
 377
 378         imxdma->name = name;
 379         imxdma->irq_handler = NULL;
 380         imxdma->err_handler = NULL;
 381         imxdma->data = NULL;
 382         imxdma->sg = NULL;
 383         local_irq_restore(flags);
 384         return 0;
 385 }
 386
 387 /**
 388  * imx_dma_free - release previously acquired channel
 389  * @dma_ch: i.MX DMA channel number
 390  */
 391 void imx_dma_free(imx_dmach_t dma_ch)
 392 {
 393         unsigned long flags;
 394         struct imx_dma_channel *imxdma = &imx_dma_channels[dma_ch];
 395
 396         if (!imxdma->name) {
 397                 printk(KERN_CRIT
 398                        "%s: trying to free channel %d which is already freed\n",
 399                        __func__, dma_ch);
 400                 return;
 401         }
 402
 403         local_irq_save(flags);
 404         /* Disable interrupts */
 405         DIMR |= (1 << dma_ch);
 406         CCR(dma_ch) &= ~CCR_CEN;
 407         imxdma->name = NULL;
 408         local_irq_restore(flags);
 409 }
 410
 411 /**
 412  * imx_dma_request_by_prio - find and request some of free channels best suiting requested priority
 413  * @name: the driver/caller own non-%NULL identification
 414  * @prio: one of the hardware distinguished priority level:
 415  *        %DMA_PRIO_HIGH, %DMA_PRIO_MEDIUM, %DMA_PRIO_LOW
 416  *
 417  * This function tries to find free channel in the specified priority group
 418  * if the priority cannot be achieved it tries to look for free channel
 419  * in the higher and then even lower priority groups.
 420  *
 421  * Return value: If there is no free channel to allocate, -%ENODEV is returned.
 422  *               On successful allocation channel is returned.
 423  */
 424 imx_dmach_t imx_dma_request_by_prio(const char *name, imx_dma_prio prio)
 425 {
 426         int i;
 427         int best;
 428
 429         switch (prio) {
 430         case (DMA_PRIO_HIGH):
 431                 best = 8;
 432                 break;
 433         case (DMA_PRIO_MEDIUM):
 434                 best = 4;
 435                 break;
 436         case (DMA_PRIO_LOW):
 437         default:
 438                 best = 0;
 439                 break;
 440         }
 441
 442         for (i = best; i < IMX_DMA_CHANNELS; i++) {
 443                 if (!imx_dma_request(i, name)) {
 444                         return i;
 445                 }
 446         }
 447
 448         for (i = best - 1; i >= 0; i--) {
 449                 if (!imx_dma_request(i, name)) {
 450                         return i;
 451                 }
 452         }
 453
 454         printk(KERN_ERR "%s: no free DMA channel found\n", __func__);
 455
 456         return -ENODEV;
 457 }
 458
 459 static irqreturn_t dma_err_handler(int irq, void *dev_id)
 460 {
 461         int i, disr = DISR;
 462         struct imx_dma_channel *channel;
 463         unsigned int err_mask = DBTOSR | DRTOSR | DSESR | DBOSR;
 464         int errcode;
 465
 466         DISR = disr & err_mask;
 467         for (i = 0; i < IMX_DMA_CHANNELS; i++) {
 468                 if(!(err_mask & (1 << i)))
 469                         continue;
 470                 channel = &imx_dma_channels[i];
 471                 errcode = 0;
 472
 473                 if (DBTOSR & (1 << i)) {
 474                         DBTOSR = (1 << i);
 475                         errcode |= IMX_DMA_ERR_BURST;
 476                 }
 477                 if (DRTOSR & (1 << i)) {
 478                         DRTOSR = (1 << i);
 479                         errcode |= IMX_DMA_ERR_REQUEST;
 480                 }
 481                 if (DSESR & (1 << i)) {
 482                         DSESR = (1 << i);
 483                         errcode |= IMX_DMA_ERR_TRANSFER;
 484                 }
 485                 if (DBOSR & (1 << i)) {
 486                         DBOSR = (1 << i);
 487                         errcode |= IMX_DMA_ERR_BUFFER;
 488                 }
 489
 490                 /*
 491                  * The cleaning of @sg field would be questionable
 492                  * there, because its value can help to compute
 493                  * remaining/transferred bytes count in the handler
 494                  */
 495                 /*imx_dma_channels[i].sg = NULL;*/
 496
 497                 if (channel->name && channel->err_handler) {
 498                         channel->err_handler(i, channel->data, errcode);
 499                         continue;
 500                 }
 501
 502                 imx_dma_channels[i].sg = NULL;
 503
 504                 printk(KERN_WARNING
 505                        "DMA timeout on channel %d (%s) -%s%s%s%s\n",
 506                        i, channel->name,
 507                        errcode&IMX_DMA_ERR_BURST?    " burst":"",
 508                        errcode&IMX_DMA_ERR_REQUEST?  " request":"",
 509                        errcode&IMX_DMA_ERR_TRANSFER? " transfer":"",
 510                        errcode&IMX_DMA_ERR_BUFFER?   " buffer":"");
 511         }
 512         return IRQ_HANDLED;
 513 }
 514
 515 static irqreturn_t dma_irq_handler(int irq, void *dev_id)
 516 {
 517         int i, disr = DISR;
 518
 519         pr_debug("imxdma: dma_irq_handler called, disr=0x%08x\n",
 520                      disr);
 521
 522         DISR = disr;
 523         for (i = 0; i < IMX_DMA_CHANNELS; i++) {
 524                 if (disr & (1 << i)) {
 525                         struct imx_dma_channel *channel = &imx_dma_channels[i];
 526                         if (channel->name) {
 527                                 if (imx_dma_sg_next(i, CNTR(i))) {
 528                                         CCR(i) &= ~CCR_CEN;
 529                                         mb();
 530                                         CCR(i) |= CCR_CEN;
 531                                 } else {
 532                                         if (channel->irq_handler)
 533                                                 channel->irq_handler(i,
 534                                                         channel->data);
 535                                 }
 536                         } else {
 537                                 /*
 538                                  * IRQ for an unregistered DMA channel:
 539                                  * let's clear the interrupts and disable it.
 540                                  */
 541                                 printk(KERN_WARNING
 542                                        "spurious IRQ for DMA channel %d\n", i);
 543                         }
 544                 }
 545         }
 546         return IRQ_HANDLED;
 547 }
 548
 549 static int __init imx_dma_init(void)
 550 {
 551         int ret;
 552         int i;
 553
 554         /* reset DMA module */
 555         DCR = DCR_DRST;
 556
 557         ret = request_irq(DMA_INT, dma_irq_handler, 0, "DMA", NULL);
 558         if (ret) {
 559                 printk(KERN_CRIT "Wow!  Can't register IRQ for DMA\n");
 560                 return ret;
 561         }
 562
 563         ret = request_irq(DMA_ERR, dma_err_handler, 0, "DMA", NULL);
 564         if (ret) {
 565                 printk(KERN_CRIT "Wow!  Can't register ERRIRQ for DMA\n");
 566                 free_irq(DMA_INT, NULL);
 567         }
 568
 569         /* enable DMA module */
 570         DCR = DCR_DEN;
 571
 572         /* clear all interrupts */
 573         DISR = (1 << IMX_DMA_CHANNELS) - 1;
 574
 575         /* enable interrupts */
 576         DIMR = (1 << IMX_DMA_CHANNELS) - 1;
 577
 578         for (i = 0; i < IMX_DMA_CHANNELS; i++) {
 579                 imx_dma_channels[i].sg = NULL;
 580                 imx_dma_channels[i].dma_num = i;
 581         }
 582
 583         return ret;
 584 }
 585
 586 arch_initcall(imx_dma_init);
 587
 588 EXPORT_SYMBOL(imx_dma_setup_single);
 589 EXPORT_SYMBOL(imx_dma_setup_sg);
 590 EXPORT_SYMBOL(imx_dma_setup_handlers);
 591 EXPORT_SYMBOL(imx_dma_enable);
 592 EXPORT_SYMBOL(imx_dma_disable);
 593 EXPORT_SYMBOL(imx_dma_request);
 594 EXPORT_SYMBOL(imx_dma_free);
 595 EXPORT_SYMBOL(imx_dma_request_by_prio);
 596 EXPORT_SYMBOL(imx_dma_channels);