root/drivers/dma/mxs-dma.c

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DEFINITIONS

This source file includes following definitions.
  1. to_mxs_dma_chan
  2. mxs_dma_reset_chan
  3. mxs_dma_enable_chan
  4. mxs_dma_disable_chan
  5. mxs_dma_pause_chan
  6. mxs_dma_resume_chan
  7. mxs_dma_tx_submit
  8. mxs_dma_tasklet
  9. mxs_dma_irq_to_chan
  10. mxs_dma_int_handler
  11. mxs_dma_alloc_chan_resources
  12. mxs_dma_free_chan_resources
  13. mxs_dma_prep_slave_sg
  14. mxs_dma_prep_dma_cyclic
  15. mxs_dma_terminate_all
  16. mxs_dma_tx_status
  17. mxs_dma_init
  18. mxs_dma_filter_fn
  19. mxs_dma_xlate
  20. mxs_dma_probe
  21. mxs_dma_module_init

   1 // SPDX-License-Identifier: GPL-2.0
   2 //
   3 // Copyright 2011 Freescale Semiconductor, Inc. All Rights Reserved.
   4 //
   5 // Refer to drivers/dma/imx-sdma.c
   6 
   7 #include <linux/init.h>
   8 #include <linux/types.h>
   9 #include <linux/mm.h>
  10 #include <linux/interrupt.h>
  11 #include <linux/clk.h>
  12 #include <linux/wait.h>
  13 #include <linux/sched.h>
  14 #include <linux/semaphore.h>
  15 #include <linux/device.h>
  16 #include <linux/dma-mapping.h>
  17 #include <linux/slab.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/dmaengine.h>
  20 #include <linux/delay.h>
  21 #include <linux/module.h>
  22 #include <linux/stmp_device.h>
  23 #include <linux/of.h>
  24 #include <linux/of_device.h>
  25 #include <linux/of_dma.h>
  26 #include <linux/list.h>
  27 #include <linux/dma/mxs-dma.h>
  28 
  29 #include <asm/irq.h>
  30 
  31 #include "dmaengine.h"
  32 
  33 /*
  34  * NOTE: The term "PIO" throughout the mxs-dma implementation means
  35  * PIO mode of mxs apbh-dma and apbx-dma.  With this working mode,
  36  * dma can program the controller registers of peripheral devices.
  37  */
  38 
  39 #define dma_is_apbh(mxs_dma)    ((mxs_dma)->type == MXS_DMA_APBH)
  40 #define apbh_is_old(mxs_dma)    ((mxs_dma)->dev_id == IMX23_DMA)
  41 
  42 #define HW_APBHX_CTRL0                          0x000
  43 #define BM_APBH_CTRL0_APB_BURST8_EN             (1 << 29)
  44 #define BM_APBH_CTRL0_APB_BURST_EN              (1 << 28)
  45 #define BP_APBH_CTRL0_RESET_CHANNEL             16
  46 #define HW_APBHX_CTRL1                          0x010
  47 #define HW_APBHX_CTRL2                          0x020
  48 #define HW_APBHX_CHANNEL_CTRL                   0x030
  49 #define BP_APBHX_CHANNEL_CTRL_RESET_CHANNEL     16
  50 /*
  51  * The offset of NXTCMDAR register is different per both dma type and version,
  52  * while stride for each channel is all the same 0x70.
  53  */
  54 #define HW_APBHX_CHn_NXTCMDAR(d, n) \
  55         (((dma_is_apbh(d) && apbh_is_old(d)) ? 0x050 : 0x110) + (n) * 0x70)
  56 #define HW_APBHX_CHn_SEMA(d, n) \
  57         (((dma_is_apbh(d) && apbh_is_old(d)) ? 0x080 : 0x140) + (n) * 0x70)
  58 #define HW_APBHX_CHn_BAR(d, n) \
  59         (((dma_is_apbh(d) && apbh_is_old(d)) ? 0x070 : 0x130) + (n) * 0x70)
  60 #define HW_APBX_CHn_DEBUG1(d, n) (0x150 + (n) * 0x70)
  61 
  62 /*
  63  * ccw bits definitions
  64  *
  65  * COMMAND:             0..1    (2)
  66  * CHAIN:               2       (1)
  67  * IRQ:                 3       (1)
  68  * NAND_LOCK:           4       (1) - not implemented
  69  * NAND_WAIT4READY:     5       (1) - not implemented
  70  * DEC_SEM:             6       (1)
  71  * WAIT4END:            7       (1)
  72  * HALT_ON_TERMINATE:   8       (1)
  73  * TERMINATE_FLUSH:     9       (1)
  74  * RESERVED:            10..11  (2)
  75  * PIO_NUM:             12..15  (4)
  76  */
  77 #define BP_CCW_COMMAND          0
  78 #define BM_CCW_COMMAND          (3 << 0)
  79 #define CCW_CHAIN               (1 << 2)
  80 #define CCW_IRQ                 (1 << 3)
  81 #define CCW_WAIT4RDY            (1 << 5)
  82 #define CCW_DEC_SEM             (1 << 6)
  83 #define CCW_WAIT4END            (1 << 7)
  84 #define CCW_HALT_ON_TERM        (1 << 8)
  85 #define CCW_TERM_FLUSH          (1 << 9)
  86 #define BP_CCW_PIO_NUM          12
  87 #define BM_CCW_PIO_NUM          (0xf << 12)
  88 
  89 #define BF_CCW(value, field)    (((value) << BP_CCW_##field) & BM_CCW_##field)
  90 
  91 #define MXS_DMA_CMD_NO_XFER     0
  92 #define MXS_DMA_CMD_WRITE       1
  93 #define MXS_DMA_CMD_READ        2
  94 #define MXS_DMA_CMD_DMA_SENSE   3       /* not implemented */
  95 
  96 struct mxs_dma_ccw {
  97         u32             next;
  98         u16             bits;
  99         u16             xfer_bytes;
 100 #define MAX_XFER_BYTES  0xff00
 101         u32             bufaddr;
 102 #define MXS_PIO_WORDS   16
 103         u32             pio_words[MXS_PIO_WORDS];
 104 };
 105 
 106 #define CCW_BLOCK_SIZE  (4 * PAGE_SIZE)
 107 #define NUM_CCW (int)(CCW_BLOCK_SIZE / sizeof(struct mxs_dma_ccw))
 108 
 109 struct mxs_dma_chan {
 110         struct mxs_dma_engine           *mxs_dma;
 111         struct dma_chan                 chan;
 112         struct dma_async_tx_descriptor  desc;
 113         struct tasklet_struct           tasklet;
 114         unsigned int                    chan_irq;
 115         struct mxs_dma_ccw              *ccw;
 116         dma_addr_t                      ccw_phys;
 117         int                             desc_count;
 118         enum dma_status                 status;
 119         unsigned int                    flags;
 120         bool                            reset;
 121 #define MXS_DMA_SG_LOOP                 (1 << 0)
 122 #define MXS_DMA_USE_SEMAPHORE           (1 << 1)
 123 };
 124 
 125 #define MXS_DMA_CHANNELS                16
 126 #define MXS_DMA_CHANNELS_MASK           0xffff
 127 
 128 enum mxs_dma_devtype {
 129         MXS_DMA_APBH,
 130         MXS_DMA_APBX,
 131 };
 132 
 133 enum mxs_dma_id {
 134         IMX23_DMA,
 135         IMX28_DMA,
 136 };
 137 
 138 struct mxs_dma_engine {
 139         enum mxs_dma_id                 dev_id;
 140         enum mxs_dma_devtype            type;
 141         void __iomem                    *base;
 142         struct clk                      *clk;
 143         struct dma_device               dma_device;
 144         struct device_dma_parameters    dma_parms;
 145         struct mxs_dma_chan             mxs_chans[MXS_DMA_CHANNELS];
 146         struct platform_device          *pdev;
 147         unsigned int                    nr_channels;
 148 };
 149 
 150 struct mxs_dma_type {
 151         enum mxs_dma_id id;
 152         enum mxs_dma_devtype type;
 153 };
 154 
 155 static struct mxs_dma_type mxs_dma_types[] = {
 156         {
 157                 .id = IMX23_DMA,
 158                 .type = MXS_DMA_APBH,
 159         }, {
 160                 .id = IMX23_DMA,
 161                 .type = MXS_DMA_APBX,
 162         }, {
 163                 .id = IMX28_DMA,
 164                 .type = MXS_DMA_APBH,
 165         }, {
 166                 .id = IMX28_DMA,
 167                 .type = MXS_DMA_APBX,
 168         }
 169 };
 170 
 171 static const struct platform_device_id mxs_dma_ids[] = {
 172         {
 173                 .name = "imx23-dma-apbh",
 174                 .driver_data = (kernel_ulong_t) &mxs_dma_types[0],
 175         }, {
 176                 .name = "imx23-dma-apbx",
 177                 .driver_data = (kernel_ulong_t) &mxs_dma_types[1],
 178         }, {
 179                 .name = "imx28-dma-apbh",
 180                 .driver_data = (kernel_ulong_t) &mxs_dma_types[2],
 181         }, {
 182                 .name = "imx28-dma-apbx",
 183                 .driver_data = (kernel_ulong_t) &mxs_dma_types[3],
 184         }, {
 185                 /* end of list */
 186         }
 187 };
 188 
 189 static const struct of_device_id mxs_dma_dt_ids[] = {
 190         { .compatible = "fsl,imx23-dma-apbh", .data = &mxs_dma_ids[0], },
 191         { .compatible = "fsl,imx23-dma-apbx", .data = &mxs_dma_ids[1], },
 192         { .compatible = "fsl,imx28-dma-apbh", .data = &mxs_dma_ids[2], },
 193         { .compatible = "fsl,imx28-dma-apbx", .data = &mxs_dma_ids[3], },
 194         { /* sentinel */ }
 195 };
 196 MODULE_DEVICE_TABLE(of, mxs_dma_dt_ids);
 197 
 198 static struct mxs_dma_chan *to_mxs_dma_chan(struct dma_chan *chan)
 199 {
 200         return container_of(chan, struct mxs_dma_chan, chan);
 201 }
 202 
 203 static void mxs_dma_reset_chan(struct dma_chan *chan)
 204 {
 205         struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
 206         struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
 207         int chan_id = mxs_chan->chan.chan_id;
 208 
 209         /*
 210          * mxs dma channel resets can cause a channel stall. To recover from a
 211          * channel stall, we have to reset the whole DMA engine. To avoid this,
 212          * we use cyclic DMA with semaphores, that are enhanced in
 213          * mxs_dma_int_handler. To reset the channel, we can simply stop writing
 214          * into the semaphore counter.
 215          */
 216         if (mxs_chan->flags & MXS_DMA_USE_SEMAPHORE &&
 217                         mxs_chan->flags & MXS_DMA_SG_LOOP) {
 218                 mxs_chan->reset = true;
 219         } else if (dma_is_apbh(mxs_dma) && apbh_is_old(mxs_dma)) {
 220                 writel(1 << (chan_id + BP_APBH_CTRL0_RESET_CHANNEL),
 221                         mxs_dma->base + HW_APBHX_CTRL0 + STMP_OFFSET_REG_SET);
 222         } else {
 223                 unsigned long elapsed = 0;
 224                 const unsigned long max_wait = 50000; /* 50ms */
 225                 void __iomem *reg_dbg1 = mxs_dma->base +
 226                                 HW_APBX_CHn_DEBUG1(mxs_dma, chan_id);
 227 
 228                 /*
 229                  * On i.MX28 APBX, the DMA channel can stop working if we reset
 230                  * the channel while it is in READ_FLUSH (0x08) state.
 231                  * We wait here until we leave the state. Then we trigger the
 232                  * reset. Waiting a maximum of 50ms, the kernel shouldn't crash
 233                  * because of this.
 234                  */
 235                 while ((readl(reg_dbg1) & 0xf) == 0x8 && elapsed < max_wait) {
 236                         udelay(100);
 237                         elapsed += 100;
 238                 }
 239 
 240                 if (elapsed >= max_wait)
 241                         dev_err(&mxs_chan->mxs_dma->pdev->dev,
 242                                         "Failed waiting for the DMA channel %d to leave state READ_FLUSH, trying to reset channel in READ_FLUSH state now\n",
 243                                         chan_id);
 244 
 245                 writel(1 << (chan_id + BP_APBHX_CHANNEL_CTRL_RESET_CHANNEL),
 246                         mxs_dma->base + HW_APBHX_CHANNEL_CTRL + STMP_OFFSET_REG_SET);
 247         }
 248 
 249         mxs_chan->status = DMA_COMPLETE;
 250 }
 251 
 252 static void mxs_dma_enable_chan(struct dma_chan *chan)
 253 {
 254         struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
 255         struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
 256         int chan_id = mxs_chan->chan.chan_id;
 257 
 258         /* set cmd_addr up */
 259         writel(mxs_chan->ccw_phys,
 260                 mxs_dma->base + HW_APBHX_CHn_NXTCMDAR(mxs_dma, chan_id));
 261 
 262         /* write 1 to SEMA to kick off the channel */
 263         if (mxs_chan->flags & MXS_DMA_USE_SEMAPHORE &&
 264                         mxs_chan->flags & MXS_DMA_SG_LOOP) {
 265                 /* A cyclic DMA consists of at least 2 segments, so initialize
 266                  * the semaphore with 2 so we have enough time to add 1 to the
 267                  * semaphore if we need to */
 268                 writel(2, mxs_dma->base + HW_APBHX_CHn_SEMA(mxs_dma, chan_id));
 269         } else {
 270                 writel(1, mxs_dma->base + HW_APBHX_CHn_SEMA(mxs_dma, chan_id));
 271         }
 272         mxs_chan->reset = false;
 273 }
 274 
 275 static void mxs_dma_disable_chan(struct dma_chan *chan)
 276 {
 277         struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
 278 
 279         mxs_chan->status = DMA_COMPLETE;
 280 }
 281 
 282 static int mxs_dma_pause_chan(struct dma_chan *chan)
 283 {
 284         struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
 285         struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
 286         int chan_id = mxs_chan->chan.chan_id;
 287 
 288         /* freeze the channel */
 289         if (dma_is_apbh(mxs_dma) && apbh_is_old(mxs_dma))
 290                 writel(1 << chan_id,
 291                         mxs_dma->base + HW_APBHX_CTRL0 + STMP_OFFSET_REG_SET);
 292         else
 293                 writel(1 << chan_id,
 294                         mxs_dma->base + HW_APBHX_CHANNEL_CTRL + STMP_OFFSET_REG_SET);
 295 
 296         mxs_chan->status = DMA_PAUSED;
 297         return 0;
 298 }
 299 
 300 static int mxs_dma_resume_chan(struct dma_chan *chan)
 301 {
 302         struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
 303         struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
 304         int chan_id = mxs_chan->chan.chan_id;
 305 
 306         /* unfreeze the channel */
 307         if (dma_is_apbh(mxs_dma) && apbh_is_old(mxs_dma))
 308                 writel(1 << chan_id,
 309                         mxs_dma->base + HW_APBHX_CTRL0 + STMP_OFFSET_REG_CLR);
 310         else
 311                 writel(1 << chan_id,
 312                         mxs_dma->base + HW_APBHX_CHANNEL_CTRL + STMP_OFFSET_REG_CLR);
 313 
 314         mxs_chan->status = DMA_IN_PROGRESS;
 315         return 0;
 316 }
 317 
 318 static dma_cookie_t mxs_dma_tx_submit(struct dma_async_tx_descriptor *tx)
 319 {
 320         return dma_cookie_assign(tx);
 321 }
 322 
 323 static void mxs_dma_tasklet(unsigned long data)
 324 {
 325         struct mxs_dma_chan *mxs_chan = (struct mxs_dma_chan *) data;
 326 
 327         dmaengine_desc_get_callback_invoke(&mxs_chan->desc, NULL);
 328 }
 329 
 330 static int mxs_dma_irq_to_chan(struct mxs_dma_engine *mxs_dma, int irq)
 331 {
 332         int i;
 333 
 334         for (i = 0; i != mxs_dma->nr_channels; ++i)
 335                 if (mxs_dma->mxs_chans[i].chan_irq == irq)
 336                         return i;
 337 
 338         return -EINVAL;
 339 }
 340 
 341 static irqreturn_t mxs_dma_int_handler(int irq, void *dev_id)
 342 {
 343         struct mxs_dma_engine *mxs_dma = dev_id;
 344         struct mxs_dma_chan *mxs_chan;
 345         u32 completed;
 346         u32 err;
 347         int chan = mxs_dma_irq_to_chan(mxs_dma, irq);
 348 
 349         if (chan < 0)
 350                 return IRQ_NONE;
 351 
 352         /* completion status */
 353         completed = readl(mxs_dma->base + HW_APBHX_CTRL1);
 354         completed = (completed >> chan) & 0x1;
 355 
 356         /* Clear interrupt */
 357         writel((1 << chan),
 358                         mxs_dma->base + HW_APBHX_CTRL1 + STMP_OFFSET_REG_CLR);
 359 
 360         /* error status */
 361         err = readl(mxs_dma->base + HW_APBHX_CTRL2);
 362         err &= (1 << (MXS_DMA_CHANNELS + chan)) | (1 << chan);
 363 
 364         /*
 365          * error status bit is in the upper 16 bits, error irq bit in the lower
 366          * 16 bits. We transform it into a simpler error code:
 367          * err: 0x00 = no error, 0x01 = TERMINATION, 0x02 = BUS_ERROR
 368          */
 369         err = (err >> (MXS_DMA_CHANNELS + chan)) + (err >> chan);
 370 
 371         /* Clear error irq */
 372         writel((1 << chan),
 373                         mxs_dma->base + HW_APBHX_CTRL2 + STMP_OFFSET_REG_CLR);
 374 
 375         /*
 376          * When both completion and error of termination bits set at the
 377          * same time, we do not take it as an error.  IOW, it only becomes
 378          * an error we need to handle here in case of either it's a bus
 379          * error or a termination error with no completion. 0x01 is termination
 380          * error, so we can subtract err & completed to get the real error case.
 381          */
 382         err -= err & completed;
 383 
 384         mxs_chan = &mxs_dma->mxs_chans[chan];
 385 
 386         if (err) {
 387                 dev_dbg(mxs_dma->dma_device.dev,
 388                         "%s: error in channel %d\n", __func__,
 389                         chan);
 390                 mxs_chan->status = DMA_ERROR;
 391                 mxs_dma_reset_chan(&mxs_chan->chan);
 392         } else if (mxs_chan->status != DMA_COMPLETE) {
 393                 if (mxs_chan->flags & MXS_DMA_SG_LOOP) {
 394                         mxs_chan->status = DMA_IN_PROGRESS;
 395                         if (mxs_chan->flags & MXS_DMA_USE_SEMAPHORE)
 396                                 writel(1, mxs_dma->base +
 397                                         HW_APBHX_CHn_SEMA(mxs_dma, chan));
 398                 } else {
 399                         mxs_chan->status = DMA_COMPLETE;
 400                 }
 401         }
 402 
 403         if (mxs_chan->status == DMA_COMPLETE) {
 404                 if (mxs_chan->reset)
 405                         return IRQ_HANDLED;
 406                 dma_cookie_complete(&mxs_chan->desc);
 407         }
 408 
 409         /* schedule tasklet on this channel */
 410         tasklet_schedule(&mxs_chan->tasklet);
 411 
 412         return IRQ_HANDLED;
 413 }
 414 
 415 static int mxs_dma_alloc_chan_resources(struct dma_chan *chan)
 416 {
 417         struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
 418         struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
 419         int ret;
 420 
 421         mxs_chan->ccw = dma_alloc_coherent(mxs_dma->dma_device.dev,
 422                                            CCW_BLOCK_SIZE,
 423                                            &mxs_chan->ccw_phys, GFP_KERNEL);
 424         if (!mxs_chan->ccw) {
 425                 ret = -ENOMEM;
 426                 goto err_alloc;
 427         }
 428 
 429         ret = request_irq(mxs_chan->chan_irq, mxs_dma_int_handler,
 430                           0, "mxs-dma", mxs_dma);
 431         if (ret)
 432                 goto err_irq;
 433 
 434         ret = clk_prepare_enable(mxs_dma->clk);
 435         if (ret)
 436                 goto err_clk;
 437 
 438         mxs_dma_reset_chan(chan);
 439 
 440         dma_async_tx_descriptor_init(&mxs_chan->desc, chan);
 441         mxs_chan->desc.tx_submit = mxs_dma_tx_submit;
 442 
 443         /* the descriptor is ready */
 444         async_tx_ack(&mxs_chan->desc);
 445 
 446         return 0;
 447 
 448 err_clk:
 449         free_irq(mxs_chan->chan_irq, mxs_dma);
 450 err_irq:
 451         dma_free_coherent(mxs_dma->dma_device.dev, CCW_BLOCK_SIZE,
 452                         mxs_chan->ccw, mxs_chan->ccw_phys);
 453 err_alloc:
 454         return ret;
 455 }
 456 
 457 static void mxs_dma_free_chan_resources(struct dma_chan *chan)
 458 {
 459         struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
 460         struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
 461 
 462         mxs_dma_disable_chan(chan);
 463 
 464         free_irq(mxs_chan->chan_irq, mxs_dma);
 465 
 466         dma_free_coherent(mxs_dma->dma_device.dev, CCW_BLOCK_SIZE,
 467                         mxs_chan->ccw, mxs_chan->ccw_phys);
 468 
 469         clk_disable_unprepare(mxs_dma->clk);
 470 }
 471 
 472 /*
 473  * How to use the flags for ->device_prep_slave_sg() :
 474  *    [1] If there is only one DMA command in the DMA chain, the code should be:
 475  *            ......
 476  *            ->device_prep_slave_sg(DMA_CTRL_ACK);
 477  *            ......
 478  *    [2] If there are two DMA commands in the DMA chain, the code should be
 479  *            ......
 480  *            ->device_prep_slave_sg(0);
 481  *            ......
 482  *            ->device_prep_slave_sg(DMA_CTRL_ACK);
 483  *            ......
 484  *    [3] If there are more than two DMA commands in the DMA chain, the code
 485  *        should be:
 486  *            ......
 487  *            ->device_prep_slave_sg(0);                                // First
 488  *            ......
 489  *            ->device_prep_slave_sg(DMA_CTRL_ACK]);
 490  *            ......
 491  *            ->device_prep_slave_sg(DMA_CTRL_ACK); // Last
 492  *            ......
 493  */
 494 static struct dma_async_tx_descriptor *mxs_dma_prep_slave_sg(
 495                 struct dma_chan *chan, struct scatterlist *sgl,
 496                 unsigned int sg_len, enum dma_transfer_direction direction,
 497                 unsigned long flags, void *context)
 498 {
 499         struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
 500         struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
 501         struct mxs_dma_ccw *ccw;
 502         struct scatterlist *sg;
 503         u32 i, j;
 504         u32 *pio;
 505         int idx = 0;
 506 
 507         if (mxs_chan->status == DMA_IN_PROGRESS)
 508                 idx = mxs_chan->desc_count;
 509 
 510         if (sg_len + idx > NUM_CCW) {
 511                 dev_err(mxs_dma->dma_device.dev,
 512                                 "maximum number of sg exceeded: %d > %d\n",
 513                                 sg_len, NUM_CCW);
 514                 goto err_out;
 515         }
 516 
 517         mxs_chan->status = DMA_IN_PROGRESS;
 518         mxs_chan->flags = 0;
 519 
 520         /*
 521          * If the sg is prepared with append flag set, the sg
 522          * will be appended to the last prepared sg.
 523          */
 524         if (idx) {
 525                 BUG_ON(idx < 1);
 526                 ccw = &mxs_chan->ccw[idx - 1];
 527                 ccw->next = mxs_chan->ccw_phys + sizeof(*ccw) * idx;
 528                 ccw->bits |= CCW_CHAIN;
 529                 ccw->bits &= ~CCW_IRQ;
 530                 ccw->bits &= ~CCW_DEC_SEM;
 531         } else {
 532                 idx = 0;
 533         }
 534 
 535         if (direction == DMA_TRANS_NONE) {
 536                 ccw = &mxs_chan->ccw[idx++];
 537                 pio = (u32 *) sgl;
 538 
 539                 for (j = 0; j < sg_len;)
 540                         ccw->pio_words[j++] = *pio++;
 541 
 542                 ccw->bits = 0;
 543                 ccw->bits |= CCW_IRQ;
 544                 ccw->bits |= CCW_DEC_SEM;
 545                 if (flags & MXS_DMA_CTRL_WAIT4END)
 546                         ccw->bits |= CCW_WAIT4END;
 547                 ccw->bits |= CCW_HALT_ON_TERM;
 548                 ccw->bits |= CCW_TERM_FLUSH;
 549                 ccw->bits |= BF_CCW(sg_len, PIO_NUM);
 550                 ccw->bits |= BF_CCW(MXS_DMA_CMD_NO_XFER, COMMAND);
 551                 if (flags & MXS_DMA_CTRL_WAIT4RDY)
 552                         ccw->bits |= CCW_WAIT4RDY;
 553         } else {
 554                 for_each_sg(sgl, sg, sg_len, i) {
 555                         if (sg_dma_len(sg) > MAX_XFER_BYTES) {
 556                                 dev_err(mxs_dma->dma_device.dev, "maximum bytes for sg entry exceeded: %d > %d\n",
 557                                                 sg_dma_len(sg), MAX_XFER_BYTES);
 558                                 goto err_out;
 559                         }
 560 
 561                         ccw = &mxs_chan->ccw[idx++];
 562 
 563                         ccw->next = mxs_chan->ccw_phys + sizeof(*ccw) * idx;
 564                         ccw->bufaddr = sg->dma_address;
 565                         ccw->xfer_bytes = sg_dma_len(sg);
 566 
 567                         ccw->bits = 0;
 568                         ccw->bits |= CCW_CHAIN;
 569                         ccw->bits |= CCW_HALT_ON_TERM;
 570                         ccw->bits |= CCW_TERM_FLUSH;
 571                         ccw->bits |= BF_CCW(direction == DMA_DEV_TO_MEM ?
 572                                         MXS_DMA_CMD_WRITE : MXS_DMA_CMD_READ,
 573                                         COMMAND);
 574 
 575                         if (i + 1 == sg_len) {
 576                                 ccw->bits &= ~CCW_CHAIN;
 577                                 ccw->bits |= CCW_IRQ;
 578                                 ccw->bits |= CCW_DEC_SEM;
 579                                 if (flags & MXS_DMA_CTRL_WAIT4END)
 580                                         ccw->bits |= CCW_WAIT4END;
 581                         }
 582                 }
 583         }
 584         mxs_chan->desc_count = idx;
 585 
 586         return &mxs_chan->desc;
 587 
 588 err_out:
 589         mxs_chan->status = DMA_ERROR;
 590         return NULL;
 591 }
 592 
 593 static struct dma_async_tx_descriptor *mxs_dma_prep_dma_cyclic(
 594                 struct dma_chan *chan, dma_addr_t dma_addr, size_t buf_len,
 595                 size_t period_len, enum dma_transfer_direction direction,
 596                 unsigned long flags)
 597 {
 598         struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
 599         struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
 600         u32 num_periods = buf_len / period_len;
 601         u32 i = 0, buf = 0;
 602 
 603         if (mxs_chan->status == DMA_IN_PROGRESS)
 604                 return NULL;
 605 
 606         mxs_chan->status = DMA_IN_PROGRESS;
 607         mxs_chan->flags |= MXS_DMA_SG_LOOP;
 608         mxs_chan->flags |= MXS_DMA_USE_SEMAPHORE;
 609 
 610         if (num_periods > NUM_CCW) {
 611                 dev_err(mxs_dma->dma_device.dev,
 612                                 "maximum number of sg exceeded: %d > %d\n",
 613                                 num_periods, NUM_CCW);
 614                 goto err_out;
 615         }
 616 
 617         if (period_len > MAX_XFER_BYTES) {
 618                 dev_err(mxs_dma->dma_device.dev,
 619                                 "maximum period size exceeded: %zu > %d\n",
 620                                 period_len, MAX_XFER_BYTES);
 621                 goto err_out;
 622         }
 623 
 624         while (buf < buf_len) {
 625                 struct mxs_dma_ccw *ccw = &mxs_chan->ccw[i];
 626 
 627                 if (i + 1 == num_periods)
 628                         ccw->next = mxs_chan->ccw_phys;
 629                 else
 630                         ccw->next = mxs_chan->ccw_phys + sizeof(*ccw) * (i + 1);
 631 
 632                 ccw->bufaddr = dma_addr;
 633                 ccw->xfer_bytes = period_len;
 634 
 635                 ccw->bits = 0;
 636                 ccw->bits |= CCW_CHAIN;
 637                 ccw->bits |= CCW_IRQ;
 638                 ccw->bits |= CCW_HALT_ON_TERM;
 639                 ccw->bits |= CCW_TERM_FLUSH;
 640                 ccw->bits |= CCW_DEC_SEM;
 641                 ccw->bits |= BF_CCW(direction == DMA_DEV_TO_MEM ?
 642                                 MXS_DMA_CMD_WRITE : MXS_DMA_CMD_READ, COMMAND);
 643 
 644                 dma_addr += period_len;
 645                 buf += period_len;
 646 
 647                 i++;
 648         }
 649         mxs_chan->desc_count = i;
 650 
 651         return &mxs_chan->desc;
 652 
 653 err_out:
 654         mxs_chan->status = DMA_ERROR;
 655         return NULL;
 656 }
 657 
 658 static int mxs_dma_terminate_all(struct dma_chan *chan)
 659 {
 660         mxs_dma_reset_chan(chan);
 661         mxs_dma_disable_chan(chan);
 662 
 663         return 0;
 664 }
 665 
 666 static enum dma_status mxs_dma_tx_status(struct dma_chan *chan,
 667                         dma_cookie_t cookie, struct dma_tx_state *txstate)
 668 {
 669         struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
 670         struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
 671         u32 residue = 0;
 672 
 673         if (mxs_chan->status == DMA_IN_PROGRESS &&
 674                         mxs_chan->flags & MXS_DMA_SG_LOOP) {
 675                 struct mxs_dma_ccw *last_ccw;
 676                 u32 bar;
 677 
 678                 last_ccw = &mxs_chan->ccw[mxs_chan->desc_count - 1];
 679                 residue = last_ccw->xfer_bytes + last_ccw->bufaddr;
 680 
 681                 bar = readl(mxs_dma->base +
 682                                 HW_APBHX_CHn_BAR(mxs_dma, chan->chan_id));
 683                 residue -= bar;
 684         }
 685 
 686         dma_set_tx_state(txstate, chan->completed_cookie, chan->cookie,
 687                         residue);
 688 
 689         return mxs_chan->status;
 690 }
 691 
 692 static int __init mxs_dma_init(struct mxs_dma_engine *mxs_dma)
 693 {
 694         int ret;
 695 
 696         ret = clk_prepare_enable(mxs_dma->clk);
 697         if (ret)
 698                 return ret;
 699 
 700         ret = stmp_reset_block(mxs_dma->base);
 701         if (ret)
 702                 goto err_out;
 703 
 704         /* enable apbh burst */
 705         if (dma_is_apbh(mxs_dma)) {
 706                 writel(BM_APBH_CTRL0_APB_BURST_EN,
 707                         mxs_dma->base + HW_APBHX_CTRL0 + STMP_OFFSET_REG_SET);
 708                 writel(BM_APBH_CTRL0_APB_BURST8_EN,
 709                         mxs_dma->base + HW_APBHX_CTRL0 + STMP_OFFSET_REG_SET);
 710         }
 711 
 712         /* enable irq for all the channels */
 713         writel(MXS_DMA_CHANNELS_MASK << MXS_DMA_CHANNELS,
 714                 mxs_dma->base + HW_APBHX_CTRL1 + STMP_OFFSET_REG_SET);
 715 
 716 err_out:
 717         clk_disable_unprepare(mxs_dma->clk);
 718         return ret;
 719 }
 720 
 721 struct mxs_dma_filter_param {
 722         unsigned int chan_id;
 723 };
 724 
 725 static bool mxs_dma_filter_fn(struct dma_chan *chan, void *fn_param)
 726 {
 727         struct mxs_dma_filter_param *param = fn_param;
 728         struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
 729         struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
 730         int chan_irq;
 731 
 732         if (chan->chan_id != param->chan_id)
 733                 return false;
 734 
 735         chan_irq = platform_get_irq(mxs_dma->pdev, param->chan_id);
 736         if (chan_irq < 0)
 737                 return false;
 738 
 739         mxs_chan->chan_irq = chan_irq;
 740 
 741         return true;
 742 }
 743 
 744 static struct dma_chan *mxs_dma_xlate(struct of_phandle_args *dma_spec,
 745                                struct of_dma *ofdma)
 746 {
 747         struct mxs_dma_engine *mxs_dma = ofdma->of_dma_data;
 748         dma_cap_mask_t mask = mxs_dma->dma_device.cap_mask;
 749         struct mxs_dma_filter_param param;
 750 
 751         if (dma_spec->args_count != 1)
 752                 return NULL;
 753 
 754         param.chan_id = dma_spec->args[0];
 755 
 756         if (param.chan_id >= mxs_dma->nr_channels)
 757                 return NULL;
 758 
 759         return __dma_request_channel(&mask, mxs_dma_filter_fn, &param,
 760                                      ofdma->of_node);
 761 }
 762 
 763 static int __init mxs_dma_probe(struct platform_device *pdev)
 764 {
 765         struct device_node *np = pdev->dev.of_node;
 766         const struct platform_device_id *id_entry;
 767         const struct of_device_id *of_id;
 768         const struct mxs_dma_type *dma_type;
 769         struct mxs_dma_engine *mxs_dma;
 770         struct resource *iores;
 771         int ret, i;
 772 
 773         mxs_dma = devm_kzalloc(&pdev->dev, sizeof(*mxs_dma), GFP_KERNEL);
 774         if (!mxs_dma)
 775                 return -ENOMEM;
 776 
 777         ret = of_property_read_u32(np, "dma-channels", &mxs_dma->nr_channels);
 778         if (ret) {
 779                 dev_err(&pdev->dev, "failed to read dma-channels\n");
 780                 return ret;
 781         }
 782 
 783         of_id = of_match_device(mxs_dma_dt_ids, &pdev->dev);
 784         if (of_id)
 785                 id_entry = of_id->data;
 786         else
 787                 id_entry = platform_get_device_id(pdev);
 788 
 789         dma_type = (struct mxs_dma_type *)id_entry->driver_data;
 790         mxs_dma->type = dma_type->type;
 791         mxs_dma->dev_id = dma_type->id;
 792 
 793         iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 794         mxs_dma->base = devm_ioremap_resource(&pdev->dev, iores);
 795         if (IS_ERR(mxs_dma->base))
 796                 return PTR_ERR(mxs_dma->base);
 797 
 798         mxs_dma->clk = devm_clk_get(&pdev->dev, NULL);
 799         if (IS_ERR(mxs_dma->clk))
 800                 return PTR_ERR(mxs_dma->clk);
 801 
 802         dma_cap_set(DMA_SLAVE, mxs_dma->dma_device.cap_mask);
 803         dma_cap_set(DMA_CYCLIC, mxs_dma->dma_device.cap_mask);
 804 
 805         INIT_LIST_HEAD(&mxs_dma->dma_device.channels);
 806 
 807         /* Initialize channel parameters */
 808         for (i = 0; i < MXS_DMA_CHANNELS; i++) {
 809                 struct mxs_dma_chan *mxs_chan = &mxs_dma->mxs_chans[i];
 810 
 811                 mxs_chan->mxs_dma = mxs_dma;
 812                 mxs_chan->chan.device = &mxs_dma->dma_device;
 813                 dma_cookie_init(&mxs_chan->chan);
 814 
 815                 tasklet_init(&mxs_chan->tasklet, mxs_dma_tasklet,
 816                              (unsigned long) mxs_chan);
 817 
 818 
 819                 /* Add the channel to mxs_chan list */
 820                 list_add_tail(&mxs_chan->chan.device_node,
 821                         &mxs_dma->dma_device.channels);
 822         }
 823 
 824         ret = mxs_dma_init(mxs_dma);
 825         if (ret)
 826                 return ret;
 827 
 828         mxs_dma->pdev = pdev;
 829         mxs_dma->dma_device.dev = &pdev->dev;
 830 
 831         /* mxs_dma gets 65535 bytes maximum sg size */
 832         mxs_dma->dma_device.dev->dma_parms = &mxs_dma->dma_parms;
 833         dma_set_max_seg_size(mxs_dma->dma_device.dev, MAX_XFER_BYTES);
 834 
 835         mxs_dma->dma_device.device_alloc_chan_resources = mxs_dma_alloc_chan_resources;
 836         mxs_dma->dma_device.device_free_chan_resources = mxs_dma_free_chan_resources;
 837         mxs_dma->dma_device.device_tx_status = mxs_dma_tx_status;
 838         mxs_dma->dma_device.device_prep_slave_sg = mxs_dma_prep_slave_sg;
 839         mxs_dma->dma_device.device_prep_dma_cyclic = mxs_dma_prep_dma_cyclic;
 840         mxs_dma->dma_device.device_pause = mxs_dma_pause_chan;
 841         mxs_dma->dma_device.device_resume = mxs_dma_resume_chan;
 842         mxs_dma->dma_device.device_terminate_all = mxs_dma_terminate_all;
 843         mxs_dma->dma_device.src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
 844         mxs_dma->dma_device.dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
 845         mxs_dma->dma_device.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
 846         mxs_dma->dma_device.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
 847         mxs_dma->dma_device.device_issue_pending = mxs_dma_enable_chan;
 848 
 849         ret = dmaenginem_async_device_register(&mxs_dma->dma_device);
 850         if (ret) {
 851                 dev_err(mxs_dma->dma_device.dev, "unable to register\n");
 852                 return ret;
 853         }
 854 
 855         ret = of_dma_controller_register(np, mxs_dma_xlate, mxs_dma);
 856         if (ret) {
 857                 dev_err(mxs_dma->dma_device.dev,
 858                         "failed to register controller\n");
 859         }
 860 
 861         dev_info(mxs_dma->dma_device.dev, "initialized\n");
 862 
 863         return 0;
 864 }
 865 
 866 static struct platform_driver mxs_dma_driver = {
 867         .driver         = {
 868                 .name   = "mxs-dma",
 869                 .of_match_table = mxs_dma_dt_ids,
 870         },
 871         .id_table       = mxs_dma_ids,
 872 };
 873 
 874 static int __init mxs_dma_module_init(void)
 875 {
 876         return platform_driver_probe(&mxs_dma_driver, mxs_dma_probe);
 877 }
 878 subsys_initcall(mxs_dma_module_init);

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