git.oblomov.eu Git - linux-2.6/blob - drivers/media/video/omap24xxcam-dma.c

   1 /*
   2  * drivers/media/video/omap24xxcam-dma.c
   3  *
   4  * Copyright (C) 2004 MontaVista Software, Inc.
   5  * Copyright (C) 2004 Texas Instruments.
   6  * Copyright (C) 2007 Nokia Corporation.
   7  *
   8  * Contact: Sakari Ailus <sakari.ailus@nokia.com>
   9  *
  10  * Based on code from Andy Lowe <source@mvista.com> and
  11  *                    David Cohen <david.cohen@indt.org.br>.
  12  *
  13  * This program is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU General Public License
  15  * version 2 as published by the Free Software Foundation.
  16  *
  17  * This program is distributed in the hope that it will be useful, but
  18  * WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20  * General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  25  * 02110-1301 USA
  26  */
  27
  28 #include <linux/kernel.h>
  29 #include <linux/io.h>
  30 #include <linux/scatterlist.h>
  31
  32 #include "omap24xxcam.h"
  33
  34 /*
  35  *
  36  * DMA hardware.
  37  *
  38  */
  39
  40 /* Ack all interrupt on CSR and IRQSTATUS_L0 */
  41 static void omap24xxcam_dmahw_ack_all(unsigned long base)
  42 {
  43         u32 csr;
  44         int i;
  45
  46         for (i = 0; i < NUM_CAMDMA_CHANNELS; ++i) {
  47                 csr = omap24xxcam_reg_in(base, CAMDMA_CSR(i));
  48                 /* ack interrupt in CSR */
  49                 omap24xxcam_reg_out(base, CAMDMA_CSR(i), csr);
  50         }
  51         omap24xxcam_reg_out(base, CAMDMA_IRQSTATUS_L0, 0xf);
  52 }
  53
  54 /* Ack dmach on CSR and IRQSTATUS_L0 */
  55 static u32 omap24xxcam_dmahw_ack_ch(unsigned long base, int dmach)
  56 {
  57         u32 csr;
  58
  59         csr = omap24xxcam_reg_in(base, CAMDMA_CSR(dmach));
  60         /* ack interrupt in CSR */
  61         omap24xxcam_reg_out(base, CAMDMA_CSR(dmach), csr);
  62         /* ack interrupt in IRQSTATUS */
  63         omap24xxcam_reg_out(base, CAMDMA_IRQSTATUS_L0, (1 << dmach));
  64
  65         return csr;
  66 }
  67
  68 static int omap24xxcam_dmahw_running(unsigned long base, int dmach)
  69 {
  70         return omap24xxcam_reg_in(base, CAMDMA_CCR(dmach)) & CAMDMA_CCR_ENABLE;
  71 }
  72
  73 static void omap24xxcam_dmahw_transfer_setup(unsigned long base, int dmach,
  74                                              dma_addr_t start, u32 len)
  75 {
  76         omap24xxcam_reg_out(base, CAMDMA_CCR(dmach),
  77                             CAMDMA_CCR_SEL_SRC_DST_SYNC
  78                             | CAMDMA_CCR_BS
  79                             | CAMDMA_CCR_DST_AMODE_POST_INC
  80                             | CAMDMA_CCR_SRC_AMODE_POST_INC
  81                             | CAMDMA_CCR_FS
  82                             | CAMDMA_CCR_WR_ACTIVE
  83                             | CAMDMA_CCR_RD_ACTIVE
  84                             | CAMDMA_CCR_SYNCHRO_CAMERA);
  85         omap24xxcam_reg_out(base, CAMDMA_CLNK_CTRL(dmach), 0);
  86         omap24xxcam_reg_out(base, CAMDMA_CEN(dmach), len);
  87         omap24xxcam_reg_out(base, CAMDMA_CFN(dmach), 1);
  88         omap24xxcam_reg_out(base, CAMDMA_CSDP(dmach),
  89                             CAMDMA_CSDP_WRITE_MODE_POSTED
  90                             | CAMDMA_CSDP_DST_BURST_EN_32
  91                             | CAMDMA_CSDP_DST_PACKED
  92                             | CAMDMA_CSDP_SRC_BURST_EN_32
  93                             | CAMDMA_CSDP_SRC_PACKED
  94                             | CAMDMA_CSDP_DATA_TYPE_8BITS);
  95         omap24xxcam_reg_out(base, CAMDMA_CSSA(dmach), 0);
  96         omap24xxcam_reg_out(base, CAMDMA_CDSA(dmach), start);
  97         omap24xxcam_reg_out(base, CAMDMA_CSEI(dmach), 0);
  98         omap24xxcam_reg_out(base, CAMDMA_CSFI(dmach), DMA_THRESHOLD);
  99         omap24xxcam_reg_out(base, CAMDMA_CDEI(dmach), 0);
 100         omap24xxcam_reg_out(base, CAMDMA_CDFI(dmach), 0);
 101         omap24xxcam_reg_out(base, CAMDMA_CSR(dmach),
 102                             CAMDMA_CSR_MISALIGNED_ERR
 103                             | CAMDMA_CSR_SECURE_ERR
 104                             | CAMDMA_CSR_TRANS_ERR
 105                             | CAMDMA_CSR_BLOCK
 106                             | CAMDMA_CSR_DROP);
 107         omap24xxcam_reg_out(base, CAMDMA_CICR(dmach),
 108                             CAMDMA_CICR_MISALIGNED_ERR_IE
 109                             | CAMDMA_CICR_SECURE_ERR_IE
 110                             | CAMDMA_CICR_TRANS_ERR_IE
 111                             | CAMDMA_CICR_BLOCK_IE
 112                             | CAMDMA_CICR_DROP_IE);
 113 }
 114
 115 static void omap24xxcam_dmahw_transfer_start(unsigned long base, int dmach)
 116 {
 117         omap24xxcam_reg_out(base, CAMDMA_CCR(dmach),
 118                             CAMDMA_CCR_SEL_SRC_DST_SYNC
 119                             | CAMDMA_CCR_BS
 120                             | CAMDMA_CCR_DST_AMODE_POST_INC
 121                             | CAMDMA_CCR_SRC_AMODE_POST_INC
 122                             | CAMDMA_CCR_ENABLE
 123                             | CAMDMA_CCR_FS
 124                             | CAMDMA_CCR_SYNCHRO_CAMERA);
 125 }
 126
 127 static void omap24xxcam_dmahw_transfer_chain(unsigned long base, int dmach,
 128                                              int free_dmach)
 129 {
 130         int prev_dmach, ch;
 131
 132         if (dmach == 0)
 133                 prev_dmach = NUM_CAMDMA_CHANNELS - 1;
 134         else
 135                 prev_dmach = dmach - 1;
 136         omap24xxcam_reg_out(base, CAMDMA_CLNK_CTRL(prev_dmach),
 137                             CAMDMA_CLNK_CTRL_ENABLE_LNK | dmach);
 138         /* Did we chain the DMA transfer before the previous one
 139          * finished?
 140          */
 141         ch = (dmach + free_dmach) % NUM_CAMDMA_CHANNELS;
 142         while (!(omap24xxcam_reg_in(base, CAMDMA_CCR(ch))
 143                  & CAMDMA_CCR_ENABLE)) {
 144                 if (ch == dmach) {
 145                         /* The previous transfer has ended and this one
 146                          * hasn't started, so we must not have chained
 147                          * to the previous one in time.  We'll have to
 148                          * start it now.
 149                          */
 150                         omap24xxcam_dmahw_transfer_start(base, dmach);
 151                         break;
 152                 } else
 153                         ch = (ch + 1) % NUM_CAMDMA_CHANNELS;
 154         }
 155 }
 156
 157 /* Abort all chained DMA transfers. After all transfers have been
 158  * aborted and the DMA controller is idle, the completion routines for
 159  * any aborted transfers will be called in sequence. The DMA
 160  * controller may not be idle after this routine completes, because
 161  * the completion routines might start new transfers.
 162  */
 163 static void omap24xxcam_dmahw_abort_ch(unsigned long base, int dmach)
 164 {
 165         /* mask all interrupts from this channel */
 166         omap24xxcam_reg_out(base, CAMDMA_CICR(dmach), 0);
 167         /* unlink this channel */
 168         omap24xxcam_reg_merge(base, CAMDMA_CLNK_CTRL(dmach), 0,
 169                               CAMDMA_CLNK_CTRL_ENABLE_LNK);
 170         /* disable this channel */
 171         omap24xxcam_reg_merge(base, CAMDMA_CCR(dmach), 0, CAMDMA_CCR_ENABLE);
 172 }
 173
 174 static void omap24xxcam_dmahw_init(unsigned long base)
 175 {
 176         omap24xxcam_reg_out(base, CAMDMA_OCP_SYSCONFIG,
 177                             CAMDMA_OCP_SYSCONFIG_MIDLEMODE_FSTANDBY
 178                             | CAMDMA_OCP_SYSCONFIG_SIDLEMODE_FIDLE
 179                             | CAMDMA_OCP_SYSCONFIG_AUTOIDLE);
 180
 181         omap24xxcam_reg_merge(base, CAMDMA_GCR, 0x10,
 182                               CAMDMA_GCR_MAX_CHANNEL_FIFO_DEPTH);
 183
 184         omap24xxcam_reg_out(base, CAMDMA_IRQENABLE_L0, 0xf);
 185 }
 186
 187 /*
 188  *
 189  * Individual DMA channel handling.
 190  *
 191  */
 192
 193 /* Start a DMA transfer from the camera to memory.
 194  * Returns zero if the transfer was successfully started, or non-zero if all
 195  * DMA channels are already in use or starting is currently inhibited.
 196  */
 197 static int omap24xxcam_dma_start(struct omap24xxcam_dma *dma, dma_addr_t start,
 198                                  u32 len, dma_callback_t callback, void *arg)
 199 {
 200         unsigned long flags;
 201         int dmach;
 202
 203         spin_lock_irqsave(&dma->lock, flags);
 204
 205         if (!dma->free_dmach || atomic_read(&dma->dma_stop)) {
 206                 spin_unlock_irqrestore(&dma->lock, flags);
 207                 return -EBUSY;
 208         }
 209
 210         dmach = dma->next_dmach;
 211
 212         dma->ch_state[dmach].callback = callback;
 213         dma->ch_state[dmach].arg = arg;
 214
 215         omap24xxcam_dmahw_transfer_setup(dma->base, dmach, start, len);
 216
 217         /* We're ready to start the DMA transfer. */
 218
 219         if (dma->free_dmach < NUM_CAMDMA_CHANNELS) {
 220                 /* A transfer is already in progress, so try to chain to it. */
 221                 omap24xxcam_dmahw_transfer_chain(dma->base, dmach,
 222                                                  dma->free_dmach);
 223         } else {
 224                 /* No transfer is in progress, so we'll just start this one
 225                  * now.
 226                  */
 227                 omap24xxcam_dmahw_transfer_start(dma->base, dmach);
 228         }
 229
 230         dma->next_dmach = (dma->next_dmach + 1) % NUM_CAMDMA_CHANNELS;
 231         dma->free_dmach--;
 232
 233         spin_unlock_irqrestore(&dma->lock, flags);
 234
 235         return 0;
 236 }
 237
 238 /* Abort all chained DMA transfers. After all transfers have been
 239  * aborted and the DMA controller is idle, the completion routines for
 240  * any aborted transfers will be called in sequence. The DMA
 241  * controller may not be idle after this routine completes, because
 242  * the completion routines might start new transfers.
 243  */
 244 static void omap24xxcam_dma_abort(struct omap24xxcam_dma *dma, u32 csr)
 245 {
 246         unsigned long flags;
 247         int dmach, i, free_dmach;
 248         dma_callback_t callback;
 249         void *arg;
 250
 251         spin_lock_irqsave(&dma->lock, flags);
 252
 253         /* stop any DMA transfers in progress */
 254         dmach = (dma->next_dmach + dma->free_dmach) % NUM_CAMDMA_CHANNELS;
 255         for (i = 0; i < NUM_CAMDMA_CHANNELS; i++) {
 256                 omap24xxcam_dmahw_abort_ch(dma->base, dmach);
 257                 dmach = (dmach + 1) % NUM_CAMDMA_CHANNELS;
 258         }
 259
 260         /* We have to be careful here because the callback routine
 261          * might start a new DMA transfer, and we only want to abort
 262          * transfers that were started before this routine was called.
 263          */
 264         free_dmach = dma->free_dmach;
 265         while ((dma->free_dmach < NUM_CAMDMA_CHANNELS) &&
 266                (free_dmach < NUM_CAMDMA_CHANNELS)) {
 267                 dmach = (dma->next_dmach + dma->free_dmach)
 268                         % NUM_CAMDMA_CHANNELS;
 269                 callback = dma->ch_state[dmach].callback;
 270                 arg = dma->ch_state[dmach].arg;
 271                 dma->free_dmach++;
 272                 free_dmach++;
 273                 if (callback) {
 274                         /* leave interrupts disabled during callback */
 275                         spin_unlock(&dma->lock);
 276                         (*callback) (dma, csr, arg);
 277                         spin_lock(&dma->lock);
 278                 }
 279         }
 280
 281         spin_unlock_irqrestore(&dma->lock, flags);
 282 }
 283
 284 /* Abort all chained DMA transfers. After all transfers have been
 285  * aborted and the DMA controller is idle, the completion routines for
 286  * any aborted transfers will be called in sequence. If the completion
 287  * routines attempt to start a new DMA transfer it will fail, so the
 288  * DMA controller will be idle after this routine completes.
 289  */
 290 static void omap24xxcam_dma_stop(struct omap24xxcam_dma *dma, u32 csr)
 291 {
 292         atomic_inc(&dma->dma_stop);
 293         omap24xxcam_dma_abort(dma, csr);
 294         atomic_dec(&dma->dma_stop);
 295 }
 296
 297 /* Camera DMA interrupt service routine. */
 298 void omap24xxcam_dma_isr(struct omap24xxcam_dma *dma)
 299 {
 300         int dmach;
 301         dma_callback_t callback;
 302         void *arg;
 303         u32 csr;
 304         const u32 csr_error = CAMDMA_CSR_MISALIGNED_ERR
 305                 | CAMDMA_CSR_SUPERVISOR_ERR | CAMDMA_CSR_SECURE_ERR
 306                 | CAMDMA_CSR_TRANS_ERR | CAMDMA_CSR_DROP;
 307
 308         spin_lock(&dma->lock);
 309
 310         if (dma->free_dmach == NUM_CAMDMA_CHANNELS) {
 311                 /* A camera DMA interrupt occurred while all channels
 312                  * are idle, so we'll acknowledge the interrupt in the
 313                  * IRQSTATUS register and exit.
 314                  */
 315                 omap24xxcam_dmahw_ack_all(dma->base);
 316                 spin_unlock(&dma->lock);
 317                 return;
 318         }
 319
 320         while (dma->free_dmach < NUM_CAMDMA_CHANNELS) {
 321                 dmach = (dma->next_dmach + dma->free_dmach)
 322                         % NUM_CAMDMA_CHANNELS;
 323                 if (omap24xxcam_dmahw_running(dma->base, dmach)) {
 324                         /* This buffer hasn't finished yet, so we're done. */
 325                         break;
 326                 }
 327                 csr = omap24xxcam_dmahw_ack_ch(dma->base, dmach);
 328                 if (csr & csr_error) {
 329                         /* A DMA error occurred, so stop all DMA
 330                          * transfers in progress.
 331                          */
 332                         spin_unlock(&dma->lock);
 333                         omap24xxcam_dma_stop(dma, csr);
 334                         return;
 335                 } else {
 336                         callback = dma->ch_state[dmach].callback;
 337                         arg = dma->ch_state[dmach].arg;
 338                         dma->free_dmach++;
 339                         if (callback) {
 340                                 spin_unlock(&dma->lock);
 341                                 (*callback) (dma, csr, arg);
 342                                 spin_lock(&dma->lock);
 343                         }
 344                 }
 345         }
 346
 347         spin_unlock(&dma->lock);
 348
 349         omap24xxcam_sgdma_process(
 350                 container_of(dma, struct omap24xxcam_sgdma, dma));
 351 }
 352
 353 void omap24xxcam_dma_hwinit(struct omap24xxcam_dma *dma)
 354 {
 355         unsigned long flags;
 356
 357         spin_lock_irqsave(&dma->lock, flags);
 358
 359         omap24xxcam_dmahw_init(dma->base);
 360
 361         spin_unlock_irqrestore(&dma->lock, flags);
 362 }
 363
 364 static void omap24xxcam_dma_init(struct omap24xxcam_dma *dma,
 365                                  unsigned long base)
 366 {
 367         int ch;
 368
 369         /* group all channels on DMA IRQ0 and unmask irq */
 370         spin_lock_init(&dma->lock);
 371         dma->base = base;
 372         dma->free_dmach = NUM_CAMDMA_CHANNELS;
 373         dma->next_dmach = 0;
 374         for (ch = 0; ch < NUM_CAMDMA_CHANNELS; ch++) {
 375                 dma->ch_state[ch].callback = NULL;
 376                 dma->ch_state[ch].arg = NULL;
 377         }
 378 }
 379
 380 /*
 381  *
 382  * Scatter-gather DMA.
 383  *
 384  * High-level DMA construct for transferring whole picture frames to
 385  * memory that is discontinuous.
 386  *
 387  */
 388
 389 /* DMA completion routine for the scatter-gather DMA fragments. */
 390 static void omap24xxcam_sgdma_callback(struct omap24xxcam_dma *dma, u32 csr,
 391                                        void *arg)
 392 {
 393         struct omap24xxcam_sgdma *sgdma =
 394                 container_of(dma, struct omap24xxcam_sgdma, dma);
 395         int sgslot = (int)arg;
 396         struct sgdma_state *sg_state;
 397         const u32 csr_error = CAMDMA_CSR_MISALIGNED_ERR
 398                 | CAMDMA_CSR_SUPERVISOR_ERR | CAMDMA_CSR_SECURE_ERR
 399                 | CAMDMA_CSR_TRANS_ERR | CAMDMA_CSR_DROP;
 400
 401         spin_lock(&sgdma->lock);
 402
 403         /* We got an interrupt, we can remove the timer */
 404         del_timer(&sgdma->reset_timer);
 405
 406         sg_state = sgdma->sg_state + sgslot;
 407         if (!sg_state->queued_sglist) {
 408                 spin_unlock(&sgdma->lock);
 409                 printk(KERN_ERR "%s: sgdma completed when none queued!\n",
 410                        __func__);
 411                 return;
 412         }
 413
 414         sg_state->csr |= csr;
 415         if (!--sg_state->queued_sglist) {
 416                 /* Queue for this sglist is empty, so check to see if we're
 417                  * done.
 418                  */
 419                 if ((sg_state->next_sglist == sg_state->sglen)
 420                     || (sg_state->csr & csr_error)) {
 421                         sgdma_callback_t callback = sg_state->callback;
 422                         void *arg = sg_state->arg;
 423                         u32 sg_csr = sg_state->csr;
 424                         /* All done with this sglist */
 425                         sgdma->free_sgdma++;
 426                         if (callback) {
 427                                 spin_unlock(&sgdma->lock);
 428                                 (*callback) (sgdma, sg_csr, arg);
 429                                 return;
 430                         }
 431                 }
 432         }
 433
 434         spin_unlock(&sgdma->lock);
 435 }
 436
 437 /* Start queued scatter-gather DMA transfers. */
 438 void omap24xxcam_sgdma_process(struct omap24xxcam_sgdma *sgdma)
 439 {
 440         unsigned long flags;
 441         int queued_sgdma, sgslot;
 442         struct sgdma_state *sg_state;
 443         const u32 csr_error = CAMDMA_CSR_MISALIGNED_ERR
 444                 | CAMDMA_CSR_SUPERVISOR_ERR | CAMDMA_CSR_SECURE_ERR
 445                 | CAMDMA_CSR_TRANS_ERR | CAMDMA_CSR_DROP;
 446
 447         spin_lock_irqsave(&sgdma->lock, flags);
 448
 449         queued_sgdma = NUM_SG_DMA - sgdma->free_sgdma;
 450         sgslot = (sgdma->next_sgdma + sgdma->free_sgdma) % NUM_SG_DMA;
 451         while (queued_sgdma > 0) {
 452                 sg_state = sgdma->sg_state + sgslot;
 453                 while ((sg_state->next_sglist < sg_state->sglen) &&
 454                        !(sg_state->csr & csr_error)) {
 455                         const struct scatterlist *sglist;
 456                         unsigned int len;
 457
 458                         sglist = sg_state->sglist + sg_state->next_sglist;
 459                         /* try to start the next DMA transfer */
 460                         if (sg_state->next_sglist + 1 == sg_state->sglen) {
 461                                 /*
 462                                  *  On the last sg, we handle the case where
 463                                  *  cam->img.pix.sizeimage % PAGE_ALIGN != 0
 464                                  */
 465                                 len = sg_state->len - sg_state->bytes_read;
 466                         } else {
 467                                 len = sg_dma_len(sglist);
 468                         }
 469
 470                         if (omap24xxcam_dma_start(&sgdma->dma,
 471                                                   sg_dma_address(sglist),
 472                                                   len,
 473                                                   omap24xxcam_sgdma_callback,
 474                                                   (void *)sgslot)) {
 475                                 /* DMA start failed */
 476                                 spin_unlock_irqrestore(&sgdma->lock, flags);
 477                                 return;
 478                         } else {
 479                                 unsigned long expires;
 480                                 /* DMA start was successful */
 481                                 sg_state->next_sglist++;
 482                                 sg_state->bytes_read += len;
 483                                 sg_state->queued_sglist++;
 484
 485                                 /* We start the reset timer */
 486                                 expires = jiffies + HZ;
 487                                 mod_timer(&sgdma->reset_timer, expires);
 488                         }
 489                 }
 490                 queued_sgdma--;
 491                 sgslot = (sgslot + 1) % NUM_SG_DMA;
 492         }
 493
 494         spin_unlock_irqrestore(&sgdma->lock, flags);
 495 }
 496
 497 /*
 498  * Queue a scatter-gather DMA transfer from the camera to memory.
 499  * Returns zero if the transfer was successfully queued, or non-zero
 500  * if all of the scatter-gather slots are already in use.
 501  */
 502 int omap24xxcam_sgdma_queue(struct omap24xxcam_sgdma *sgdma,
 503                             const struct scatterlist *sglist, int sglen,
 504                             int len, sgdma_callback_t callback, void *arg)
 505 {
 506         unsigned long flags;
 507         struct sgdma_state *sg_state;
 508
 509         if ((sglen < 0) || ((sglen > 0) & !sglist))
 510                 return -EINVAL;
 511
 512         spin_lock_irqsave(&sgdma->lock, flags);
 513
 514         if (!sgdma->free_sgdma) {
 515                 spin_unlock_irqrestore(&sgdma->lock, flags);
 516                 return -EBUSY;
 517         }
 518
 519         sg_state = sgdma->sg_state + sgdma->next_sgdma;
 520
 521         sg_state->sglist = sglist;
 522         sg_state->sglen = sglen;
 523         sg_state->next_sglist = 0;
 524         sg_state->bytes_read = 0;
 525         sg_state->len = len;
 526         sg_state->queued_sglist = 0;
 527         sg_state->csr = 0;
 528         sg_state->callback = callback;
 529         sg_state->arg = arg;
 530
 531         sgdma->next_sgdma = (sgdma->next_sgdma + 1) % NUM_SG_DMA;
 532         sgdma->free_sgdma--;
 533
 534         spin_unlock_irqrestore(&sgdma->lock, flags);
 535
 536         omap24xxcam_sgdma_process(sgdma);
 537
 538         return 0;
 539 }
 540
 541 /* Sync scatter-gather DMA by aborting any DMA transfers currently in progress.
 542  * Any queued scatter-gather DMA transactions that have not yet been started
 543  * will remain queued.  The DMA controller will be idle after this routine
 544  * completes.  When the scatter-gather queue is restarted, the next
 545  * scatter-gather DMA transfer will begin at the start of a new transaction.
 546  */
 547 void omap24xxcam_sgdma_sync(struct omap24xxcam_sgdma *sgdma)
 548 {
 549         unsigned long flags;
 550         int sgslot;
 551         struct sgdma_state *sg_state;
 552         u32 csr = CAMDMA_CSR_TRANS_ERR;
 553
 554         /* stop any DMA transfers in progress */
 555         omap24xxcam_dma_stop(&sgdma->dma, csr);
 556
 557         spin_lock_irqsave(&sgdma->lock, flags);
 558
 559         if (sgdma->free_sgdma < NUM_SG_DMA) {
 560                 sgslot = (sgdma->next_sgdma + sgdma->free_sgdma) % NUM_SG_DMA;
 561                 sg_state = sgdma->sg_state + sgslot;
 562                 if (sg_state->next_sglist != 0) {
 563                         /* This DMA transfer was in progress, so abort it. */
 564                         sgdma_callback_t callback = sg_state->callback;
 565                         void *arg = sg_state->arg;
 566                         sgdma->free_sgdma++;
 567                         if (callback) {
 568                                 /* leave interrupts masked */
 569                                 spin_unlock(&sgdma->lock);
 570                                 (*callback) (sgdma, csr, arg);
 571                                 spin_lock(&sgdma->lock);
 572                         }
 573                 }
 574         }
 575
 576         spin_unlock_irqrestore(&sgdma->lock, flags);
 577 }
 578
 579 void omap24xxcam_sgdma_init(struct omap24xxcam_sgdma *sgdma,
 580                             unsigned long base,
 581                             void (*reset_callback)(unsigned long data),
 582                             unsigned long reset_callback_data)
 583 {
 584         int sg;
 585
 586         spin_lock_init(&sgdma->lock);
 587         sgdma->free_sgdma = NUM_SG_DMA;
 588         sgdma->next_sgdma = 0;
 589         for (sg = 0; sg < NUM_SG_DMA; sg++) {
 590                 sgdma->sg_state[sg].sglen = 0;
 591                 sgdma->sg_state[sg].next_sglist = 0;
 592                 sgdma->sg_state[sg].bytes_read = 0;
 593                 sgdma->sg_state[sg].queued_sglist = 0;
 594                 sgdma->sg_state[sg].csr = 0;
 595                 sgdma->sg_state[sg].callback = NULL;
 596                 sgdma->sg_state[sg].arg = NULL;
 597         }
 598
 599         omap24xxcam_dma_init(&sgdma->dma, base);
 600         setup_timer(&sgdma->reset_timer, reset_callback, reset_callback_data);
 601 }