drivers/dma/stm32-dma.c

   1 /*
   2  * Driver for STM32 DMA controller
   3  *
   4  * Inspired by dma-jz4740.c and tegra20-apb-dma.c
   5  *
   6  * Copyright (C) M'boumba Cedric Madianga 2015
   7  * Author: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
   8  *
   9  * License terms:  GNU General Public License (GPL), version 2
  10  */
  11
  12 #include <linux/clk.h>
  13 #include <linux/delay.h>
  14 #include <linux/dmaengine.h>
  15 #include <linux/dma-mapping.h>
  16 #include <linux/err.h>
  17 #include <linux/init.h>
  18 #include <linux/jiffies.h>
  19 #include <linux/list.h>
  20 #include <linux/module.h>
  21 #include <linux/of.h>
  22 #include <linux/of_device.h>
  23 #include <linux/of_dma.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/reset.h>
  26 #include <linux/sched.h>
  27 #include <linux/slab.h>
  28
  29 #include "virt-dma.h"
  30
  31 #define STM32_DMA_LISR                  0x0000 /* DMA Low Int Status Reg */
  32 #define STM32_DMA_HISR                  0x0004 /* DMA High Int Status Reg */
  33 #define STM32_DMA_LIFCR                 0x0008 /* DMA Low Int Flag Clear Reg */
  34 #define STM32_DMA_HIFCR                 0x000c /* DMA High Int Flag Clear Reg */
  35 #define STM32_DMA_TCI                   BIT(5) /* Transfer Complete Interrupt */
  36 #define STM32_DMA_TEI                   BIT(3) /* Transfer Error Interrupt */
  37 #define STM32_DMA_DMEI                  BIT(2) /* Direct Mode Error Interrupt */
  38 #define STM32_DMA_FEI                   BIT(0) /* FIFO Error Interrupt */
  39
  40 /* DMA Stream x Configuration Register */
  41 #define STM32_DMA_SCR(x)                (0x0010 + 0x18 * (x)) /* x = 0..7 */
  42 #define STM32_DMA_SCR_REQ(n)            ((n & 0x7) << 25)
  43 #define STM32_DMA_SCR_MBURST_MASK       GENMASK(24, 23)
  44 #define STM32_DMA_SCR_MBURST(n)         ((n & 0x3) << 23)
  45 #define STM32_DMA_SCR_PBURST_MASK       GENMASK(22, 21)
  46 #define STM32_DMA_SCR_PBURST(n)         ((n & 0x3) << 21)
  47 #define STM32_DMA_SCR_PL_MASK           GENMASK(17, 16)
  48 #define STM32_DMA_SCR_PL(n)             ((n & 0x3) << 16)
  49 #define STM32_DMA_SCR_MSIZE_MASK        GENMASK(14, 13)
  50 #define STM32_DMA_SCR_MSIZE(n)          ((n & 0x3) << 13)
  51 #define STM32_DMA_SCR_PSIZE_MASK        GENMASK(12, 11)
  52 #define STM32_DMA_SCR_PSIZE(n)          ((n & 0x3) << 11)
  53 #define STM32_DMA_SCR_PSIZE_GET(n)      ((n & STM32_DMA_SCR_PSIZE_MASK) >> 11)
  54 #define STM32_DMA_SCR_DIR_MASK          GENMASK(7, 6)
  55 #define STM32_DMA_SCR_DIR(n)            ((n & 0x3) << 6)
  56 #define STM32_DMA_SCR_CT                BIT(19) /* Target in double buffer */
  57 #define STM32_DMA_SCR_DBM               BIT(18) /* Double Buffer Mode */
  58 #define STM32_DMA_SCR_PINCOS            BIT(15) /* Peripheral inc offset size */
  59 #define STM32_DMA_SCR_MINC              BIT(10) /* Memory increment mode */
  60 #define STM32_DMA_SCR_PINC              BIT(9) /* Peripheral increment mode */
  61 #define STM32_DMA_SCR_CIRC              BIT(8) /* Circular mode */
  62 #define STM32_DMA_SCR_PFCTRL            BIT(5) /* Peripheral Flow Controller */
  63 #define STM32_DMA_SCR_TCIE              BIT(4) /* Transfer Cplete Int Enable*/
  64 #define STM32_DMA_SCR_TEIE              BIT(2) /* Transfer Error Int Enable */
  65 #define STM32_DMA_SCR_DMEIE             BIT(1) /* Direct Mode Err Int Enable */
  66 #define STM32_DMA_SCR_EN                BIT(0) /* Stream Enable */
  67 #define STM32_DMA_SCR_CFG_MASK          (STM32_DMA_SCR_PINC \
  68                                         | STM32_DMA_SCR_MINC \
  69                                         | STM32_DMA_SCR_PINCOS \
  70                                         | STM32_DMA_SCR_PL_MASK)
  71 #define STM32_DMA_SCR_IRQ_MASK          (STM32_DMA_SCR_TCIE \
  72                                         | STM32_DMA_SCR_TEIE \
  73                                         | STM32_DMA_SCR_DMEIE)
  74
  75 /* DMA Stream x number of data register */
  76 #define STM32_DMA_SNDTR(x)              (0x0014 + 0x18 * (x))
  77
  78 /* DMA stream peripheral address register */
  79 #define STM32_DMA_SPAR(x)               (0x0018 + 0x18 * (x))
  80
  81 /* DMA stream x memory 0 address register */
  82 #define STM32_DMA_SM0AR(x)              (0x001c + 0x18 * (x))
  83
  84 /* DMA stream x memory 1 address register */
  85 #define STM32_DMA_SM1AR(x)              (0x0020 + 0x18 * (x))
  86
  87 /* DMA stream x FIFO control register */
  88 #define STM32_DMA_SFCR(x)               (0x0024 + 0x18 * (x))
  89 #define STM32_DMA_SFCR_FTH_MASK         GENMASK(1, 0)
  90 #define STM32_DMA_SFCR_FTH(n)           (n & STM32_DMA_SFCR_FTH_MASK)
  91 #define STM32_DMA_SFCR_FEIE             BIT(7) /* FIFO error interrupt enable */
  92 #define STM32_DMA_SFCR_DMDIS            BIT(2) /* Direct mode disable */
  93 #define STM32_DMA_SFCR_MASK             (STM32_DMA_SFCR_FEIE \
  94                                         | STM32_DMA_SFCR_DMDIS)
  95
  96 /* DMA direction */
  97 #define STM32_DMA_DEV_TO_MEM            0x00
  98 #define STM32_DMA_MEM_TO_DEV            0x01
  99 #define STM32_DMA_MEM_TO_MEM            0x02
 100
 101 /* DMA priority level */
 102 #define STM32_DMA_PRIORITY_LOW          0x00
 103 #define STM32_DMA_PRIORITY_MEDIUM       0x01
 104 #define STM32_DMA_PRIORITY_HIGH         0x02
 105 #define STM32_DMA_PRIORITY_VERY_HIGH    0x03
 106
 107 /* DMA FIFO threshold selection */
 108 #define STM32_DMA_FIFO_THRESHOLD_1QUARTERFULL           0x00
 109 #define STM32_DMA_FIFO_THRESHOLD_HALFFULL               0x01
 110 #define STM32_DMA_FIFO_THRESHOLD_3QUARTERSFULL          0x02
 111 #define STM32_DMA_FIFO_THRESHOLD_FULL                   0x03
 112
 113 #define STM32_DMA_MAX_DATA_ITEMS        0xffff
 114 #define STM32_DMA_MAX_CHANNELS          0x08
 115 #define STM32_DMA_MAX_REQUEST_ID        0x08
 116 #define STM32_DMA_MAX_DATA_PARAM        0x03
 117
 118 enum stm32_dma_width {
 119         STM32_DMA_BYTE,
 120         STM32_DMA_HALF_WORD,
 121         STM32_DMA_WORD,
 122 };
 123
 124 enum stm32_dma_burst_size {
 125         STM32_DMA_BURST_SINGLE,
 126         STM32_DMA_BURST_INCR4,
 127         STM32_DMA_BURST_INCR8,
 128         STM32_DMA_BURST_INCR16,
 129 };
 130
 131 struct stm32_dma_cfg {
 132         u32 channel_id;
 133         u32 request_line;
 134         u32 stream_config;
 135         u32 threshold;
 136 };
 137
 138 struct stm32_dma_chan_reg {
 139         u32 dma_lisr;
 140         u32 dma_hisr;
 141         u32 dma_lifcr;
 142         u32 dma_hifcr;
 143         u32 dma_scr;
 144         u32 dma_sndtr;
 145         u32 dma_spar;
 146         u32 dma_sm0ar;
 147         u32 dma_sm1ar;
 148         u32 dma_sfcr;
 149 };
 150
 151 struct stm32_dma_sg_req {
 152         u32 len;
 153         struct stm32_dma_chan_reg chan_reg;
 154 };
 155
 156 struct stm32_dma_desc {
 157         struct virt_dma_desc vdesc;
 158         bool cyclic;
 159         u32 num_sgs;
 160         struct stm32_dma_sg_req sg_req[];
 161 };
 162
 163 struct stm32_dma_chan {
 164         struct virt_dma_chan vchan;
 165         bool config_init;
 166         bool busy;
 167         u32 id;
 168         u32 irq;
 169         struct stm32_dma_desc *desc;
 170         u32 next_sg;
 171         struct dma_slave_config dma_sconfig;
 172         struct stm32_dma_chan_reg chan_reg;
 173 };
 174
 175 struct stm32_dma_device {
 176         struct dma_device ddev;
 177         void __iomem *base;
 178         struct clk *clk;
 179         struct reset_control *rst;
 180         bool mem2mem;
 181         struct stm32_dma_chan chan[STM32_DMA_MAX_CHANNELS];
 182 };
 183
 184 static struct stm32_dma_device *stm32_dma_get_dev(struct stm32_dma_chan *chan)
 185 {
 186         return container_of(chan->vchan.chan.device, struct stm32_dma_device,
 187                             ddev);
 188 }
 189
 190 static struct stm32_dma_chan *to_stm32_dma_chan(struct dma_chan *c)
 191 {
 192         return container_of(c, struct stm32_dma_chan, vchan.chan);
 193 }
 194
 195 static struct stm32_dma_desc *to_stm32_dma_desc(struct virt_dma_desc *vdesc)
 196 {
 197         return container_of(vdesc, struct stm32_dma_desc, vdesc);
 198 }
 199
 200 static struct device *chan2dev(struct stm32_dma_chan *chan)
 201 {
 202         return &chan->vchan.chan.dev->device;
 203 }
 204
 205 static u32 stm32_dma_read(struct stm32_dma_device *dmadev, u32 reg)
 206 {
 207         return readl_relaxed(dmadev->base + reg);
 208 }
 209
 210 static void stm32_dma_write(struct stm32_dma_device *dmadev, u32 reg, u32 val)
 211 {
 212         writel_relaxed(val, dmadev->base + reg);
 213 }
 214
 215 static struct stm32_dma_desc *stm32_dma_alloc_desc(u32 num_sgs)
 216 {
 217         return kzalloc(sizeof(struct stm32_dma_desc) +
 218                        sizeof(struct stm32_dma_sg_req) * num_sgs, GFP_NOWAIT);
 219 }
 220
 221 static int stm32_dma_get_width(struct stm32_dma_chan *chan,
 222                                enum dma_slave_buswidth width)
 223 {
 224         switch (width) {
 225         case DMA_SLAVE_BUSWIDTH_1_BYTE:
 226                 return STM32_DMA_BYTE;
 227         case DMA_SLAVE_BUSWIDTH_2_BYTES:
 228                 return STM32_DMA_HALF_WORD;
 229         case DMA_SLAVE_BUSWIDTH_4_BYTES:
 230                 return STM32_DMA_WORD;
 231         default:
 232                 dev_err(chan2dev(chan), "Dma bus width not supported\n");
 233                 return -EINVAL;
 234         }
 235 }
 236
 237 static int stm32_dma_get_burst(struct stm32_dma_chan *chan, u32 maxburst)
 238 {
 239         switch (maxburst) {
 240         case 0:
 241         case 1:
 242                 return STM32_DMA_BURST_SINGLE;
 243         case 4:
 244                 return STM32_DMA_BURST_INCR4;
 245         case 8:
 246                 return STM32_DMA_BURST_INCR8;
 247         case 16:
 248                 return STM32_DMA_BURST_INCR16;
 249         default:
 250                 dev_err(chan2dev(chan), "Dma burst size not supported\n");
 251                 return -EINVAL;
 252         }
 253 }
 254
 255 static void stm32_dma_set_fifo_config(struct stm32_dma_chan *chan,
 256                                       u32 src_maxburst, u32 dst_maxburst)
 257 {
 258         chan->chan_reg.dma_sfcr &= ~STM32_DMA_SFCR_MASK;
 259         chan->chan_reg.dma_scr &= ~STM32_DMA_SCR_DMEIE;
 260
 261         if ((!src_maxburst) && (!dst_maxburst)) {
 262                 /* Using direct mode */
 263                 chan->chan_reg.dma_scr |= STM32_DMA_SCR_DMEIE;
 264         } else {
 265                 /* Using FIFO mode */
 266                 chan->chan_reg.dma_sfcr |= STM32_DMA_SFCR_MASK;
 267         }
 268 }
 269
 270 static int stm32_dma_slave_config(struct dma_chan *c,
 271                                   struct dma_slave_config *config)
 272 {
 273         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 274
 275         memcpy(&chan->dma_sconfig, config, sizeof(*config));
 276
 277         chan->config_init = true;
 278
 279         return 0;
 280 }
 281
 282 static u32 stm32_dma_irq_status(struct stm32_dma_chan *chan)
 283 {
 284         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 285         u32 flags, dma_isr;
 286
 287         /*
 288          * Read "flags" from DMA_xISR register corresponding to the selected
 289          * DMA channel at the correct bit offset inside that register.
 290          *
 291          * If (ch % 4) is 2 or 3, left shift the mask by 16 bits.
 292          * If (ch % 4) is 1 or 3, additionally left shift the mask by 6 bits.
 293          */
 294
 295         if (chan->id & 4)
 296                 dma_isr = stm32_dma_read(dmadev, STM32_DMA_HISR);
 297         else
 298                 dma_isr = stm32_dma_read(dmadev, STM32_DMA_LISR);
 299
 300         flags = dma_isr >> (((chan->id & 2) << 3) | ((chan->id & 1) * 6));
 301
 302         return flags;
 303 }
 304
 305 static void stm32_dma_irq_clear(struct stm32_dma_chan *chan, u32 flags)
 306 {
 307         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 308         u32 dma_ifcr;
 309
 310         /*
 311          * Write "flags" to the DMA_xIFCR register corresponding to the selected
 312          * DMA channel at the correct bit offset inside that register.
 313          *
 314          * If (ch % 4) is 2 or 3, left shift the mask by 16 bits.
 315          * If (ch % 4) is 1 or 3, additionally left shift the mask by 6 bits.
 316          */
 317         dma_ifcr = flags << (((chan->id & 2) << 3) | ((chan->id & 1) * 6));
 318
 319         if (chan->id & 4)
 320                 stm32_dma_write(dmadev, STM32_DMA_HIFCR, dma_ifcr);
 321         else
 322                 stm32_dma_write(dmadev, STM32_DMA_LIFCR, dma_ifcr);
 323 }
 324
 325 static int stm32_dma_disable_chan(struct stm32_dma_chan *chan)
 326 {
 327         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 328         unsigned long timeout = jiffies + msecs_to_jiffies(5000);
 329         u32 dma_scr, id;
 330
 331         id = chan->id;
 332         dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id));
 333
 334         if (dma_scr & STM32_DMA_SCR_EN) {
 335                 dma_scr &= ~STM32_DMA_SCR_EN;
 336                 stm32_dma_write(dmadev, STM32_DMA_SCR(id), dma_scr);
 337
 338                 do {
 339                         dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id));
 340                         dma_scr &= STM32_DMA_SCR_EN;
 341                         if (!dma_scr)
 342                                 break;
 343
 344                         if (time_after_eq(jiffies, timeout)) {
 345                                 dev_err(chan2dev(chan), "%s: timeout!\n",
 346                                         __func__);
 347                                 return -EBUSY;
 348                         }
 349                         cond_resched();
 350                 } while (1);
 351         }
 352
 353         return 0;
 354 }
 355
 356 static void stm32_dma_stop(struct stm32_dma_chan *chan)
 357 {
 358         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 359         u32 dma_scr, dma_sfcr, status;
 360         int ret;
 361
 362         /* Disable interrupts */
 363         dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id));
 364         dma_scr &= ~STM32_DMA_SCR_IRQ_MASK;
 365         stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), dma_scr);
 366         dma_sfcr = stm32_dma_read(dmadev, STM32_DMA_SFCR(chan->id));
 367         dma_sfcr &= ~STM32_DMA_SFCR_FEIE;
 368         stm32_dma_write(dmadev, STM32_DMA_SFCR(chan->id), dma_sfcr);
 369
 370         /* Disable DMA */
 371         ret = stm32_dma_disable_chan(chan);
 372         if (ret < 0)
 373                 return;
 374
 375         /* Clear interrupt status if it is there */
 376         status = stm32_dma_irq_status(chan);
 377         if (status) {
 378                 dev_dbg(chan2dev(chan), "%s(): clearing interrupt: 0x%08x\n",
 379                         __func__, status);
 380                 stm32_dma_irq_clear(chan, status);
 381         }
 382
 383         chan->busy = false;
 384 }
 385
 386 static int stm32_dma_terminate_all(struct dma_chan *c)
 387 {
 388         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 389         unsigned long flags;
 390         LIST_HEAD(head);
 391
 392         spin_lock_irqsave(&chan->vchan.lock, flags);
 393
 394         if (chan->busy) {
 395                 stm32_dma_stop(chan);
 396                 chan->desc = NULL;
 397         }
 398
 399         vchan_get_all_descriptors(&chan->vchan, &head);
 400         spin_unlock_irqrestore(&chan->vchan.lock, flags);
 401         vchan_dma_desc_free_list(&chan->vchan, &head);
 402
 403         return 0;
 404 }
 405
 406 static void stm32_dma_dump_reg(struct stm32_dma_chan *chan)
 407 {
 408         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 409         u32 scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id));
 410         u32 ndtr = stm32_dma_read(dmadev, STM32_DMA_SNDTR(chan->id));
 411         u32 spar = stm32_dma_read(dmadev, STM32_DMA_SPAR(chan->id));
 412         u32 sm0ar = stm32_dma_read(dmadev, STM32_DMA_SM0AR(chan->id));
 413         u32 sm1ar = stm32_dma_read(dmadev, STM32_DMA_SM1AR(chan->id));
 414         u32 sfcr = stm32_dma_read(dmadev, STM32_DMA_SFCR(chan->id));
 415
 416         dev_dbg(chan2dev(chan), "SCR:   0x%08x\n", scr);
 417         dev_dbg(chan2dev(chan), "NDTR:  0x%08x\n", ndtr);
 418         dev_dbg(chan2dev(chan), "SPAR:  0x%08x\n", spar);
 419         dev_dbg(chan2dev(chan), "SM0AR: 0x%08x\n", sm0ar);
 420         dev_dbg(chan2dev(chan), "SM1AR: 0x%08x\n", sm1ar);
 421         dev_dbg(chan2dev(chan), "SFCR:  0x%08x\n", sfcr);
 422 }
 423
 424 static int stm32_dma_start_transfer(struct stm32_dma_chan *chan)
 425 {
 426         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 427         struct virt_dma_desc *vdesc;
 428         struct stm32_dma_sg_req *sg_req;
 429         struct stm32_dma_chan_reg *reg;
 430         u32 status;
 431         int ret;
 432
 433         ret = stm32_dma_disable_chan(chan);
 434         if (ret < 0)
 435                 return ret;
 436
 437         if (!chan->desc) {
 438                 vdesc = vchan_next_desc(&chan->vchan);
 439                 if (!vdesc)
 440                         return -EPERM;
 441
 442                 chan->desc = to_stm32_dma_desc(vdesc);
 443                 chan->next_sg = 0;
 444         }
 445
 446         if (chan->next_sg == chan->desc->num_sgs)
 447                 chan->next_sg = 0;
 448
 449         sg_req = &chan->desc->sg_req[chan->next_sg];
 450         reg = &sg_req->chan_reg;
 451
 452         stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), reg->dma_scr);
 453         stm32_dma_write(dmadev, STM32_DMA_SPAR(chan->id), reg->dma_spar);
 454         stm32_dma_write(dmadev, STM32_DMA_SM0AR(chan->id), reg->dma_sm0ar);
 455         stm32_dma_write(dmadev, STM32_DMA_SFCR(chan->id), reg->dma_sfcr);
 456         stm32_dma_write(dmadev, STM32_DMA_SM1AR(chan->id), reg->dma_sm1ar);
 457         stm32_dma_write(dmadev, STM32_DMA_SNDTR(chan->id), reg->dma_sndtr);
 458
 459         chan->next_sg++;
 460
 461         /* Clear interrupt status if it is there */
 462         status = stm32_dma_irq_status(chan);
 463         if (status)
 464                 stm32_dma_irq_clear(chan, status);
 465
 466         stm32_dma_dump_reg(chan);
 467
 468         /* Start DMA */
 469         reg->dma_scr |= STM32_DMA_SCR_EN;
 470         stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), reg->dma_scr);
 471
 472         chan->busy = true;
 473
 474         return 0;
 475 }
 476
 477 static void stm32_dma_configure_next_sg(struct stm32_dma_chan *chan)
 478 {
 479         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 480         struct stm32_dma_sg_req *sg_req;
 481         u32 dma_scr, dma_sm0ar, dma_sm1ar, id;
 482
 483         id = chan->id;
 484         dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id));
 485
 486         if (dma_scr & STM32_DMA_SCR_DBM) {
 487                 if (chan->next_sg == chan->desc->num_sgs)
 488                         chan->next_sg = 0;
 489
 490                 sg_req = &chan->desc->sg_req[chan->next_sg];
 491
 492                 if (dma_scr & STM32_DMA_SCR_CT) {
 493                         dma_sm0ar = sg_req->chan_reg.dma_sm0ar;
 494                         stm32_dma_write(dmadev, STM32_DMA_SM0AR(id), dma_sm0ar);
 495                         dev_dbg(chan2dev(chan), "CT=1 <=> SM0AR: 0x%08x\n",
 496                                 stm32_dma_read(dmadev, STM32_DMA_SM0AR(id)));
 497                 } else {
 498                         dma_sm1ar = sg_req->chan_reg.dma_sm1ar;
 499                         stm32_dma_write(dmadev, STM32_DMA_SM1AR(id), dma_sm1ar);
 500                         dev_dbg(chan2dev(chan), "CT=0 <=> SM1AR: 0x%08x\n",
 501                                 stm32_dma_read(dmadev, STM32_DMA_SM1AR(id)));
 502                 }
 503
 504                 chan->next_sg++;
 505         }
 506 }
 507
 508 static void stm32_dma_handle_chan_done(struct stm32_dma_chan *chan)
 509 {
 510         if (chan->desc) {
 511                 if (chan->desc->cyclic) {
 512                         vchan_cyclic_callback(&chan->desc->vdesc);
 513                         stm32_dma_configure_next_sg(chan);
 514                 } else {
 515                         chan->busy = false;
 516                         if (chan->next_sg == chan->desc->num_sgs) {
 517                                 list_del(&chan->desc->vdesc.node);
 518                                 vchan_cookie_complete(&chan->desc->vdesc);
 519                                 chan->desc = NULL;
 520                         }
 521                         stm32_dma_start_transfer(chan);
 522                 }
 523         }
 524 }
 525
 526 static irqreturn_t stm32_dma_chan_irq(int irq, void *devid)
 527 {
 528         struct stm32_dma_chan *chan = devid;
 529         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 530         u32 status, scr;
 531
 532         spin_lock(&chan->vchan.lock);
 533
 534         status = stm32_dma_irq_status(chan);
 535         scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id));
 536
 537         if ((status & STM32_DMA_TCI) && (scr & STM32_DMA_SCR_TCIE)) {
 538                 stm32_dma_irq_clear(chan, STM32_DMA_TCI);
 539                 stm32_dma_handle_chan_done(chan);
 540
 541         } else {
 542                 stm32_dma_irq_clear(chan, status);
 543                 dev_err(chan2dev(chan), "DMA error: status=0x%08x\n", status);
 544         }
 545
 546         spin_unlock(&chan->vchan.lock);
 547
 548         return IRQ_HANDLED;
 549 }
 550
 551 static void stm32_dma_issue_pending(struct dma_chan *c)
 552 {
 553         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 554         unsigned long flags;
 555         int ret;
 556
 557         spin_lock_irqsave(&chan->vchan.lock, flags);
 558         if (!chan->busy) {
 559                 if (vchan_issue_pending(&chan->vchan) && !chan->desc) {
 560                         ret = stm32_dma_start_transfer(chan);
 561                         if ((!ret) && (chan->desc->cyclic))
 562                                 stm32_dma_configure_next_sg(chan);
 563                 }
 564         }
 565         spin_unlock_irqrestore(&chan->vchan.lock, flags);
 566 }
 567
 568 static int stm32_dma_set_xfer_param(struct stm32_dma_chan *chan,
 569                                     enum dma_transfer_direction direction,
 570                                     enum dma_slave_buswidth *buswidth)
 571 {
 572         enum dma_slave_buswidth src_addr_width, dst_addr_width;
 573         int src_bus_width, dst_bus_width;
 574         int src_burst_size, dst_burst_size;
 575         u32 src_maxburst, dst_maxburst;
 576         u32 dma_scr = 0;
 577
 578         src_addr_width = chan->dma_sconfig.src_addr_width;
 579         dst_addr_width = chan->dma_sconfig.dst_addr_width;
 580         src_maxburst = chan->dma_sconfig.src_maxburst;
 581         dst_maxburst = chan->dma_sconfig.dst_maxburst;
 582
 583         switch (direction) {
 584         case DMA_MEM_TO_DEV:
 585                 dst_bus_width = stm32_dma_get_width(chan, dst_addr_width);
 586                 if (dst_bus_width < 0)
 587                         return dst_bus_width;
 588
 589                 dst_burst_size = stm32_dma_get_burst(chan, dst_maxburst);
 590                 if (dst_burst_size < 0)
 591                         return dst_burst_size;
 592
 593                 if (!src_addr_width)
 594                         src_addr_width = dst_addr_width;
 595
 596                 src_bus_width = stm32_dma_get_width(chan, src_addr_width);
 597                 if (src_bus_width < 0)
 598                         return src_bus_width;
 599
 600                 src_burst_size = stm32_dma_get_burst(chan, src_maxburst);
 601                 if (src_burst_size < 0)
 602                         return src_burst_size;
 603
 604                 dma_scr = STM32_DMA_SCR_DIR(STM32_DMA_MEM_TO_DEV) |
 605                         STM32_DMA_SCR_PSIZE(dst_bus_width) |
 606                         STM32_DMA_SCR_MSIZE(src_bus_width) |
 607                         STM32_DMA_SCR_PBURST(dst_burst_size) |
 608                         STM32_DMA_SCR_MBURST(src_burst_size);
 609
 610                 chan->chan_reg.dma_spar = chan->dma_sconfig.dst_addr;
 611                 *buswidth = dst_addr_width;
 612                 break;
 613
 614         case DMA_DEV_TO_MEM:
 615                 src_bus_width = stm32_dma_get_width(chan, src_addr_width);
 616                 if (src_bus_width < 0)
 617                         return src_bus_width;
 618
 619                 src_burst_size = stm32_dma_get_burst(chan, src_maxburst);
 620                 if (src_burst_size < 0)
 621                         return src_burst_size;
 622
 623                 if (!dst_addr_width)
 624                         dst_addr_width = src_addr_width;
 625
 626                 dst_bus_width = stm32_dma_get_width(chan, dst_addr_width);
 627                 if (dst_bus_width < 0)
 628                         return dst_bus_width;
 629
 630                 dst_burst_size = stm32_dma_get_burst(chan, dst_maxburst);
 631                 if (dst_burst_size < 0)
 632                         return dst_burst_size;
 633
 634                 dma_scr = STM32_DMA_SCR_DIR(STM32_DMA_DEV_TO_MEM) |
 635                         STM32_DMA_SCR_PSIZE(src_bus_width) |
 636                         STM32_DMA_SCR_MSIZE(dst_bus_width) |
 637                         STM32_DMA_SCR_PBURST(src_burst_size) |
 638                         STM32_DMA_SCR_MBURST(dst_burst_size);
 639
 640                 chan->chan_reg.dma_spar = chan->dma_sconfig.src_addr;
 641                 *buswidth = chan->dma_sconfig.src_addr_width;
 642                 break;
 643
 644         default:
 645                 dev_err(chan2dev(chan), "Dma direction is not supported\n");
 646                 return -EINVAL;
 647         }
 648
 649         stm32_dma_set_fifo_config(chan, src_maxburst, dst_maxburst);
 650
 651         chan->chan_reg.dma_scr &= ~(STM32_DMA_SCR_DIR_MASK |
 652                         STM32_DMA_SCR_PSIZE_MASK | STM32_DMA_SCR_MSIZE_MASK |
 653                         STM32_DMA_SCR_PBURST_MASK | STM32_DMA_SCR_MBURST_MASK);
 654         chan->chan_reg.dma_scr |= dma_scr;
 655
 656         return 0;
 657 }
 658
 659 static void stm32_dma_clear_reg(struct stm32_dma_chan_reg *regs)
 660 {
 661         memset(regs, 0, sizeof(struct stm32_dma_chan_reg));
 662 }
 663
 664 static struct dma_async_tx_descriptor *stm32_dma_prep_slave_sg(
 665         struct dma_chan *c, struct scatterlist *sgl,
 666         u32 sg_len, enum dma_transfer_direction direction,
 667         unsigned long flags, void *context)
 668 {
 669         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 670         struct stm32_dma_desc *desc;
 671         struct scatterlist *sg;
 672         enum dma_slave_buswidth buswidth;
 673         u32 nb_data_items;
 674         int i, ret;
 675
 676         if (!chan->config_init) {
 677                 dev_err(chan2dev(chan), "dma channel is not configured\n");
 678                 return NULL;
 679         }
 680
 681         if (sg_len < 1) {
 682                 dev_err(chan2dev(chan), "Invalid segment length %d\n", sg_len);
 683                 return NULL;
 684         }
 685
 686         desc = stm32_dma_alloc_desc(sg_len);
 687         if (!desc)
 688                 return NULL;
 689
 690         ret = stm32_dma_set_xfer_param(chan, direction, &buswidth);
 691         if (ret < 0)
 692                 goto err;
 693
 694         /* Set peripheral flow controller */
 695         if (chan->dma_sconfig.device_fc)
 696                 chan->chan_reg.dma_scr |= STM32_DMA_SCR_PFCTRL;
 697         else
 698                 chan->chan_reg.dma_scr &= ~STM32_DMA_SCR_PFCTRL;
 699
 700         for_each_sg(sgl, sg, sg_len, i) {
 701                 desc->sg_req[i].len = sg_dma_len(sg);
 702
 703                 nb_data_items = desc->sg_req[i].len / buswidth;
 704                 if (nb_data_items > STM32_DMA_MAX_DATA_ITEMS) {
 705                         dev_err(chan2dev(chan), "nb items not supported\n");
 706                         goto err;
 707                 }
 708
 709                 stm32_dma_clear_reg(&desc->sg_req[i].chan_reg);
 710                 desc->sg_req[i].chan_reg.dma_scr = chan->chan_reg.dma_scr;
 711                 desc->sg_req[i].chan_reg.dma_sfcr = chan->chan_reg.dma_sfcr;
 712                 desc->sg_req[i].chan_reg.dma_spar = chan->chan_reg.dma_spar;
 713                 desc->sg_req[i].chan_reg.dma_sm0ar = sg_dma_address(sg);
 714                 desc->sg_req[i].chan_reg.dma_sm1ar = sg_dma_address(sg);
 715                 desc->sg_req[i].chan_reg.dma_sndtr = nb_data_items;
 716         }
 717
 718         desc->num_sgs = sg_len;
 719         desc->cyclic = false;
 720
 721         return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
 722
 723 err:
 724         kfree(desc);
 725         return NULL;
 726 }
 727
 728 static struct dma_async_tx_descriptor *stm32_dma_prep_dma_cyclic(
 729         struct dma_chan *c, dma_addr_t buf_addr, size_t buf_len,
 730         size_t period_len, enum dma_transfer_direction direction,
 731         unsigned long flags)
 732 {
 733         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 734         struct stm32_dma_desc *desc;
 735         enum dma_slave_buswidth buswidth;
 736         u32 num_periods, nb_data_items;
 737         int i, ret;
 738
 739         if (!buf_len || !period_len) {
 740                 dev_err(chan2dev(chan), "Invalid buffer/period len\n");
 741                 return NULL;
 742         }
 743
 744         if (!chan->config_init) {
 745                 dev_err(chan2dev(chan), "dma channel is not configured\n");
 746                 return NULL;
 747         }
 748
 749         if (buf_len % period_len) {
 750                 dev_err(chan2dev(chan), "buf_len not multiple of period_len\n");
 751                 return NULL;
 752         }
 753
 754         /*
 755          * We allow to take more number of requests till DMA is
 756          * not started. The driver will loop over all requests.
 757          * Once DMA is started then new requests can be queued only after
 758          * terminating the DMA.
 759          */
 760         if (chan->busy) {
 761                 dev_err(chan2dev(chan), "Request not allowed when dma busy\n");
 762                 return NULL;
 763         }
 764
 765         ret = stm32_dma_set_xfer_param(chan, direction, &buswidth);
 766         if (ret < 0)
 767                 return NULL;
 768
 769         nb_data_items = period_len / buswidth;
 770         if (nb_data_items > STM32_DMA_MAX_DATA_ITEMS) {
 771                 dev_err(chan2dev(chan), "number of items not supported\n");
 772                 return NULL;
 773         }
 774
 775         /*  Enable Circular mode or double buffer mode */
 776         if (buf_len == period_len)
 777                 chan->chan_reg.dma_scr |= STM32_DMA_SCR_CIRC;
 778         else
 779                 chan->chan_reg.dma_scr |= STM32_DMA_SCR_DBM;
 780
 781         /* Clear periph ctrl if client set it */
 782         chan->chan_reg.dma_scr &= ~STM32_DMA_SCR_PFCTRL;
 783
 784         num_periods = buf_len / period_len;
 785
 786         desc = stm32_dma_alloc_desc(num_periods);
 787         if (!desc)
 788                 return NULL;
 789
 790         for (i = 0; i < num_periods; i++) {
 791                 desc->sg_req[i].len = period_len;
 792
 793                 stm32_dma_clear_reg(&desc->sg_req[i].chan_reg);
 794                 desc->sg_req[i].chan_reg.dma_scr = chan->chan_reg.dma_scr;
 795                 desc->sg_req[i].chan_reg.dma_sfcr = chan->chan_reg.dma_sfcr;
 796                 desc->sg_req[i].chan_reg.dma_spar = chan->chan_reg.dma_spar;
 797                 desc->sg_req[i].chan_reg.dma_sm0ar = buf_addr;
 798                 desc->sg_req[i].chan_reg.dma_sm1ar = buf_addr;
 799                 desc->sg_req[i].chan_reg.dma_sndtr = nb_data_items;
 800                 buf_addr += period_len;
 801         }
 802
 803         desc->num_sgs = num_periods;
 804         desc->cyclic = true;
 805
 806         return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
 807 }
 808
 809 static struct dma_async_tx_descriptor *stm32_dma_prep_dma_memcpy(
 810         struct dma_chan *c, dma_addr_t dest,
 811         dma_addr_t src, size_t len, unsigned long flags)
 812 {
 813         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 814         u32 num_sgs;
 815         struct stm32_dma_desc *desc;
 816         size_t xfer_count, offset;
 817         int i;
 818
 819         num_sgs = DIV_ROUND_UP(len, STM32_DMA_MAX_DATA_ITEMS);
 820         desc = stm32_dma_alloc_desc(num_sgs);
 821         if (!desc)
 822                 return NULL;
 823
 824         for (offset = 0, i = 0; offset < len; offset += xfer_count, i++) {
 825                 xfer_count = min_t(size_t, len - offset,
 826                                    STM32_DMA_MAX_DATA_ITEMS);
 827
 828                 desc->sg_req[i].len = xfer_count;
 829
 830                 stm32_dma_clear_reg(&desc->sg_req[i].chan_reg);
 831                 desc->sg_req[i].chan_reg.dma_scr =
 832                         STM32_DMA_SCR_DIR(STM32_DMA_MEM_TO_MEM) |
 833                         STM32_DMA_SCR_MINC |
 834                         STM32_DMA_SCR_PINC |
 835                         STM32_DMA_SCR_TCIE |
 836                         STM32_DMA_SCR_TEIE;
 837                 desc->sg_req[i].chan_reg.dma_sfcr = STM32_DMA_SFCR_DMDIS |
 838                         STM32_DMA_SFCR_FTH(STM32_DMA_FIFO_THRESHOLD_FULL) |
 839                         STM32_DMA_SFCR_FEIE;
 840                 desc->sg_req[i].chan_reg.dma_spar = src + offset;
 841                 desc->sg_req[i].chan_reg.dma_sm0ar = dest + offset;
 842                 desc->sg_req[i].chan_reg.dma_sndtr = xfer_count;
 843         }
 844
 845         desc->num_sgs = num_sgs;
 846         desc->cyclic = false;
 847
 848         return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
 849 }
 850
 851 static size_t stm32_dma_desc_residue(struct stm32_dma_chan *chan,
 852                                      struct stm32_dma_desc *desc,
 853                                      u32 next_sg)
 854 {
 855         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 856         u32 dma_scr, width, residue, count;
 857         int i;
 858
 859         residue = 0;
 860
 861         for (i = next_sg; i < desc->num_sgs; i++)
 862                 residue += desc->sg_req[i].len;
 863
 864         if (next_sg != 0) {
 865                 dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id));
 866                 width = STM32_DMA_SCR_PSIZE_GET(dma_scr);
 867                 count = stm32_dma_read(dmadev, STM32_DMA_SNDTR(chan->id));
 868
 869                 residue += count << width;
 870         }
 871
 872         return residue;
 873 }
 874
 875 static enum dma_status stm32_dma_tx_status(struct dma_chan *c,
 876                                            dma_cookie_t cookie,
 877                                            struct dma_tx_state *state)
 878 {
 879         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 880         struct virt_dma_desc *vdesc;
 881         enum dma_status status;
 882         unsigned long flags;
 883         u32 residue;
 884
 885         status = dma_cookie_status(c, cookie, state);
 886         if ((status == DMA_COMPLETE) || (!state))
 887                 return status;
 888
 889         spin_lock_irqsave(&chan->vchan.lock, flags);
 890         vdesc = vchan_find_desc(&chan->vchan, cookie);
 891         if (cookie == chan->desc->vdesc.tx.cookie) {
 892                 residue = stm32_dma_desc_residue(chan, chan->desc,
 893                                                  chan->next_sg);
 894         } else if (vdesc) {
 895                 residue = stm32_dma_desc_residue(chan,
 896                                                  to_stm32_dma_desc(vdesc), 0);
 897         } else {
 898                 residue = 0;
 899         }
 900
 901         dma_set_residue(state, residue);
 902
 903         spin_unlock_irqrestore(&chan->vchan.lock, flags);
 904
 905         return status;
 906 }
 907
 908 static int stm32_dma_alloc_chan_resources(struct dma_chan *c)
 909 {
 910         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 911         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 912         int ret;
 913
 914         chan->config_init = false;
 915         ret = clk_prepare_enable(dmadev->clk);
 916         if (ret < 0) {
 917                 dev_err(chan2dev(chan), "clk_prepare_enable failed: %d\n", ret);
 918                 return ret;
 919         }
 920
 921         ret = stm32_dma_disable_chan(chan);
 922         if (ret < 0)
 923                 clk_disable_unprepare(dmadev->clk);
 924
 925         return ret;
 926 }
 927
 928 static void stm32_dma_free_chan_resources(struct dma_chan *c)
 929 {
 930         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 931         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 932         unsigned long flags;
 933
 934         dev_dbg(chan2dev(chan), "Freeing channel %d\n", chan->id);
 935
 936         if (chan->busy) {
 937                 spin_lock_irqsave(&chan->vchan.lock, flags);
 938                 stm32_dma_stop(chan);
 939                 chan->desc = NULL;
 940                 spin_unlock_irqrestore(&chan->vchan.lock, flags);
 941         }
 942
 943         clk_disable_unprepare(dmadev->clk);
 944
 945         vchan_free_chan_resources(to_virt_chan(c));
 946 }
 947
 948 static void stm32_dma_desc_free(struct virt_dma_desc *vdesc)
 949 {
 950         kfree(container_of(vdesc, struct stm32_dma_desc, vdesc));
 951 }
 952
 953 static void stm32_dma_set_config(struct stm32_dma_chan *chan,
 954                           struct stm32_dma_cfg *cfg)
 955 {
 956         stm32_dma_clear_reg(&chan->chan_reg);
 957
 958         chan->chan_reg.dma_scr = cfg->stream_config & STM32_DMA_SCR_CFG_MASK;
 959         chan->chan_reg.dma_scr |= STM32_DMA_SCR_REQ(cfg->request_line);
 960
 961         /* Enable Interrupts  */
 962         chan->chan_reg.dma_scr |= STM32_DMA_SCR_TEIE | STM32_DMA_SCR_TCIE;
 963
 964         chan->chan_reg.dma_sfcr = cfg->threshold & STM32_DMA_SFCR_FTH_MASK;
 965 }
 966
 967 static struct dma_chan *stm32_dma_of_xlate(struct of_phandle_args *dma_spec,
 968                                            struct of_dma *ofdma)
 969 {
 970         struct stm32_dma_device *dmadev = ofdma->of_dma_data;
 971         struct stm32_dma_cfg cfg;
 972         struct stm32_dma_chan *chan;
 973         struct dma_chan *c;
 974
 975         if (dma_spec->args_count < 3)
 976                 return NULL;
 977
 978         cfg.channel_id = dma_spec->args[0];
 979         cfg.request_line = dma_spec->args[1];
 980         cfg.stream_config = dma_spec->args[2];
 981         cfg.threshold = 0;
 982
 983         if ((cfg.channel_id >= STM32_DMA_MAX_CHANNELS) || (cfg.request_line >=
 984                                 STM32_DMA_MAX_REQUEST_ID))
 985                 return NULL;
 986
 987         if (dma_spec->args_count > 3)
 988                 cfg.threshold = dma_spec->args[3];
 989
 990         chan = &dmadev->chan[cfg.channel_id];
 991
 992         c = dma_get_slave_channel(&chan->vchan.chan);
 993         if (c)
 994                 stm32_dma_set_config(chan, &cfg);
 995
 996         return c;
 997 }
 998
 999 static const struct of_device_id stm32_dma_of_match[] = {
1000         { .compatible = "st,stm32-dma", },
1001         { /* sentinel */ },
1002 };
1003 MODULE_DEVICE_TABLE(of, stm32_dma_of_match);
1004
1005 static int stm32_dma_probe(struct platform_device *pdev)
1006 {
1007         struct stm32_dma_chan *chan;
1008         struct stm32_dma_device *dmadev;
1009         struct dma_device *dd;
1010         const struct of_device_id *match;
1011         struct resource *res;
1012         int i, ret;
1013
1014         match = of_match_device(stm32_dma_of_match, &pdev->dev);
1015         if (!match) {
1016                 dev_err(&pdev->dev, "Error: No device match found\n");
1017                 return -ENODEV;
1018         }
1019
1020         dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev), GFP_KERNEL);
1021         if (!dmadev)
1022                 return -ENOMEM;
1023
1024         dd = &dmadev->ddev;
1025
1026         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1027         dmadev->base = devm_ioremap_resource(&pdev->dev, res);
1028         if (IS_ERR(dmadev->base))
1029                 return PTR_ERR(dmadev->base);
1030
1031         dmadev->clk = devm_clk_get(&pdev->dev, NULL);
1032         if (IS_ERR(dmadev->clk)) {
1033                 dev_err(&pdev->dev, "Error: Missing controller clock\n");
1034                 return PTR_ERR(dmadev->clk);
1035         }
1036
1037         dmadev->mem2mem = of_property_read_bool(pdev->dev.of_node,
1038                                                 "st,mem2mem");
1039
1040         dmadev->rst = devm_reset_control_get(&pdev->dev, NULL);
1041         if (!IS_ERR(dmadev->rst)) {
1042                 reset_control_assert(dmadev->rst);
1043                 udelay(2);
1044                 reset_control_deassert(dmadev->rst);
1045         }
1046
1047         dma_cap_set(DMA_SLAVE, dd->cap_mask);
1048         dma_cap_set(DMA_PRIVATE, dd->cap_mask);
1049         dma_cap_set(DMA_CYCLIC, dd->cap_mask);
1050         dd->device_alloc_chan_resources = stm32_dma_alloc_chan_resources;
1051         dd->device_free_chan_resources = stm32_dma_free_chan_resources;
1052         dd->device_tx_status = stm32_dma_tx_status;
1053         dd->device_issue_pending = stm32_dma_issue_pending;
1054         dd->device_prep_slave_sg = stm32_dma_prep_slave_sg;
1055         dd->device_prep_dma_cyclic = stm32_dma_prep_dma_cyclic;
1056         dd->device_config = stm32_dma_slave_config;
1057         dd->device_terminate_all = stm32_dma_terminate_all;
1058         dd->src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
1059                 BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
1060                 BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
1061         dd->dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
1062                 BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
1063                 BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
1064         dd->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
1065         dd->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
1066         dd->dev = &pdev->dev;
1067         INIT_LIST_HEAD(&dd->channels);
1068
1069         if (dmadev->mem2mem) {
1070                 dma_cap_set(DMA_MEMCPY, dd->cap_mask);
1071                 dd->device_prep_dma_memcpy = stm32_dma_prep_dma_memcpy;
1072                 dd->directions |= BIT(DMA_MEM_TO_MEM);
1073         }
1074
1075         for (i = 0; i < STM32_DMA_MAX_CHANNELS; i++) {
1076                 chan = &dmadev->chan[i];
1077                 chan->id = i;
1078                 chan->vchan.desc_free = stm32_dma_desc_free;
1079                 vchan_init(&chan->vchan, dd);
1080         }
1081
1082         ret = dma_async_device_register(dd);
1083         if (ret)
1084                 return ret;
1085
1086         for (i = 0; i < STM32_DMA_MAX_CHANNELS; i++) {
1087                 chan = &dmadev->chan[i];
1088                 res = platform_get_resource(pdev, IORESOURCE_IRQ, i);
1089                 if (!res) {
1090                         ret = -EINVAL;
1091                         dev_err(&pdev->dev, "No irq resource for chan %d\n", i);
1092                         goto err_unregister;
1093                 }
1094                 chan->irq = res->start;
1095                 ret = devm_request_irq(&pdev->dev, chan->irq,
1096                                        stm32_dma_chan_irq, 0,
1097                                        dev_name(chan2dev(chan)), chan);
1098                 if (ret) {
1099                         dev_err(&pdev->dev,
1100                                 "request_irq failed with err %d channel %d\n",
1101                                 ret, i);
1102                         goto err_unregister;
1103                 }
1104         }
1105
1106         ret = of_dma_controller_register(pdev->dev.of_node,
1107                                          stm32_dma_of_xlate, dmadev);
1108         if (ret < 0) {
1109                 dev_err(&pdev->dev,
1110                         "STM32 DMA DMA OF registration failed %d\n", ret);
1111                 goto err_unregister;
1112         }
1113
1114         platform_set_drvdata(pdev, dmadev);
1115
1116         dev_info(&pdev->dev, "STM32 DMA driver registered\n");
1117
1118         return 0;
1119
1120 err_unregister:
1121         dma_async_device_unregister(dd);
1122
1123         return ret;
1124 }
1125
1126 static struct platform_driver stm32_dma_driver = {
1127         .driver = {
1128                 .name = "stm32-dma",
1129                 .of_match_table = stm32_dma_of_match,
1130         },
1131 };
1132
1133 static int __init stm32_dma_init(void)
1134 {
1135         return platform_driver_probe(&stm32_dma_driver, stm32_dma_probe);
1136 }
1137 subsys_initcall(stm32_dma_init);