drivers/dma/stm32-dma.c

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This source file includes following definitions.
stm32_dma_get_dev
to_stm32_dma_chan
to_stm32_dma_desc
chan2dev
stm32_dma_read
stm32_dma_write
stm32_dma_get_width
stm32_dma_get_max_width
stm32_dma_fifo_threshold_is_allowed
stm32_dma_is_burst_possible
stm32_dma_get_best_burst
stm32_dma_get_burst
stm32_dma_set_fifo_config
stm32_dma_slave_config
stm32_dma_irq_status
stm32_dma_irq_clear
stm32_dma_disable_chan
stm32_dma_stop
stm32_dma_terminate_all
stm32_dma_synchronize
stm32_dma_dump_reg
stm32_dma_start_transfer
stm32_dma_configure_next_sg
stm32_dma_handle_chan_done
stm32_dma_chan_irq
stm32_dma_issue_pending
stm32_dma_set_xfer_param
stm32_dma_clear_reg
stm32_dma_prep_slave_sg
stm32_dma_prep_dma_cyclic
stm32_dma_prep_dma_memcpy
stm32_dma_get_remaining_bytes
stm32_dma_is_current_sg
stm32_dma_desc_residue
stm32_dma_tx_status
stm32_dma_alloc_chan_resources
stm32_dma_free_chan_resources
stm32_dma_desc_free
stm32_dma_set_config
stm32_dma_of_xlate
stm32_dma_probe
stm32_dma_runtime_suspend
stm32_dma_runtime_resume
stm32_dma_init
   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Driver for STM32 DMA controller
   4  *
   5  * Inspired by dma-jz4740.c and tegra20-apb-dma.c
   6  *
   7  * Copyright (C) M'boumba Cedric Madianga 2015
   8  * Author: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
   9  *         Pierre-Yves Mordret <pierre-yves.mordret@st.com>
  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/pm_runtime.h>
  26 #include <linux/reset.h>
  27 #include <linux/sched.h>
  28 #include <linux/slab.h>
  29 
  30 #include "virt-dma.h"
  31 
  32 #define STM32_DMA_LISR                  0x0000 /* DMA Low Int Status Reg */
  33 #define STM32_DMA_HISR                  0x0004 /* DMA High Int Status Reg */
  34 #define STM32_DMA_LIFCR                 0x0008 /* DMA Low Int Flag Clear Reg */
  35 #define STM32_DMA_HIFCR                 0x000c /* DMA High Int Flag Clear Reg */
  36 #define STM32_DMA_TCI                   BIT(5) /* Transfer Complete Interrupt */
  37 #define STM32_DMA_HTI                   BIT(4) /* Half Transfer Interrupt */
  38 #define STM32_DMA_TEI                   BIT(3) /* Transfer Error Interrupt */
  39 #define STM32_DMA_DMEI                  BIT(2) /* Direct Mode Error Interrupt */
  40 #define STM32_DMA_FEI                   BIT(0) /* FIFO Error Interrupt */
  41 #define STM32_DMA_MASKI                 (STM32_DMA_TCI \
  42                                          | STM32_DMA_TEI \
  43                                          | STM32_DMA_DMEI \
  44                                          | STM32_DMA_FEI)
  45 
  46 /* DMA Stream x Configuration Register */
  47 #define STM32_DMA_SCR(x)                (0x0010 + 0x18 * (x)) /* x = 0..7 */
  48 #define STM32_DMA_SCR_REQ(n)            ((n & 0x7) << 25)
  49 #define STM32_DMA_SCR_MBURST_MASK       GENMASK(24, 23)
  50 #define STM32_DMA_SCR_MBURST(n)         ((n & 0x3) << 23)
  51 #define STM32_DMA_SCR_PBURST_MASK       GENMASK(22, 21)
  52 #define STM32_DMA_SCR_PBURST(n)         ((n & 0x3) << 21)
  53 #define STM32_DMA_SCR_PL_MASK           GENMASK(17, 16)
  54 #define STM32_DMA_SCR_PL(n)             ((n & 0x3) << 16)
  55 #define STM32_DMA_SCR_MSIZE_MASK        GENMASK(14, 13)
  56 #define STM32_DMA_SCR_MSIZE(n)          ((n & 0x3) << 13)
  57 #define STM32_DMA_SCR_PSIZE_MASK        GENMASK(12, 11)
  58 #define STM32_DMA_SCR_PSIZE(n)          ((n & 0x3) << 11)
  59 #define STM32_DMA_SCR_PSIZE_GET(n)      ((n & STM32_DMA_SCR_PSIZE_MASK) >> 11)
  60 #define STM32_DMA_SCR_DIR_MASK          GENMASK(7, 6)
  61 #define STM32_DMA_SCR_DIR(n)            ((n & 0x3) << 6)
  62 #define STM32_DMA_SCR_CT                BIT(19) /* Target in double buffer */
  63 #define STM32_DMA_SCR_DBM               BIT(18) /* Double Buffer Mode */
  64 #define STM32_DMA_SCR_PINCOS            BIT(15) /* Peripheral inc offset size */
  65 #define STM32_DMA_SCR_MINC              BIT(10) /* Memory increment mode */
  66 #define STM32_DMA_SCR_PINC              BIT(9) /* Peripheral increment mode */
  67 #define STM32_DMA_SCR_CIRC              BIT(8) /* Circular mode */
  68 #define STM32_DMA_SCR_PFCTRL            BIT(5) /* Peripheral Flow Controller */
  69 #define STM32_DMA_SCR_TCIE              BIT(4) /* Transfer Complete Int Enable
  70                                                 */
  71 #define STM32_DMA_SCR_TEIE              BIT(2) /* Transfer Error Int Enable */
  72 #define STM32_DMA_SCR_DMEIE             BIT(1) /* Direct Mode Err Int Enable */
  73 #define STM32_DMA_SCR_EN                BIT(0) /* Stream Enable */
  74 #define STM32_DMA_SCR_CFG_MASK          (STM32_DMA_SCR_PINC \
  75                                         | STM32_DMA_SCR_MINC \
  76                                         | STM32_DMA_SCR_PINCOS \
  77                                         | STM32_DMA_SCR_PL_MASK)
  78 #define STM32_DMA_SCR_IRQ_MASK          (STM32_DMA_SCR_TCIE \
  79                                         | STM32_DMA_SCR_TEIE \
  80                                         | STM32_DMA_SCR_DMEIE)
  81 
  82 /* DMA Stream x number of data register */
  83 #define STM32_DMA_SNDTR(x)              (0x0014 + 0x18 * (x))
  84 
  85 /* DMA stream peripheral address register */
  86 #define STM32_DMA_SPAR(x)               (0x0018 + 0x18 * (x))
  87 
  88 /* DMA stream x memory 0 address register */
  89 #define STM32_DMA_SM0AR(x)              (0x001c + 0x18 * (x))
  90 
  91 /* DMA stream x memory 1 address register */
  92 #define STM32_DMA_SM1AR(x)              (0x0020 + 0x18 * (x))
  93 
  94 /* DMA stream x FIFO control register */
  95 #define STM32_DMA_SFCR(x)               (0x0024 + 0x18 * (x))
  96 #define STM32_DMA_SFCR_FTH_MASK         GENMASK(1, 0)
  97 #define STM32_DMA_SFCR_FTH(n)           (n & STM32_DMA_SFCR_FTH_MASK)
  98 #define STM32_DMA_SFCR_FEIE             BIT(7) /* FIFO error interrupt enable */
  99 #define STM32_DMA_SFCR_DMDIS            BIT(2) /* Direct mode disable */
 100 #define STM32_DMA_SFCR_MASK             (STM32_DMA_SFCR_FEIE \
 101                                         | STM32_DMA_SFCR_DMDIS)
 102 
 103 /* DMA direction */
 104 #define STM32_DMA_DEV_TO_MEM            0x00
 105 #define STM32_DMA_MEM_TO_DEV            0x01
 106 #define STM32_DMA_MEM_TO_MEM            0x02
 107 
 108 /* DMA priority level */
 109 #define STM32_DMA_PRIORITY_LOW          0x00
 110 #define STM32_DMA_PRIORITY_MEDIUM       0x01
 111 #define STM32_DMA_PRIORITY_HIGH         0x02
 112 #define STM32_DMA_PRIORITY_VERY_HIGH    0x03
 113 
 114 /* DMA FIFO threshold selection */
 115 #define STM32_DMA_FIFO_THRESHOLD_1QUARTERFULL           0x00
 116 #define STM32_DMA_FIFO_THRESHOLD_HALFFULL               0x01
 117 #define STM32_DMA_FIFO_THRESHOLD_3QUARTERSFULL          0x02
 118 #define STM32_DMA_FIFO_THRESHOLD_FULL                   0x03
 119 
 120 #define STM32_DMA_MAX_DATA_ITEMS        0xffff
 121 /*
 122  * Valid transfer starts from @0 to @0xFFFE leading to unaligned scatter
 123  * gather at boundary. Thus it's safer to round down this value on FIFO
 124  * size (16 Bytes)
 125  */
 126 #define STM32_DMA_ALIGNED_MAX_DATA_ITEMS        \
 127         ALIGN_DOWN(STM32_DMA_MAX_DATA_ITEMS, 16)
 128 #define STM32_DMA_MAX_CHANNELS          0x08
 129 #define STM32_DMA_MAX_REQUEST_ID        0x08
 130 #define STM32_DMA_MAX_DATA_PARAM        0x03
 131 #define STM32_DMA_FIFO_SIZE             16      /* FIFO is 16 bytes */
 132 #define STM32_DMA_MIN_BURST             4
 133 #define STM32_DMA_MAX_BURST             16
 134 
 135 /* DMA Features */
 136 #define STM32_DMA_THRESHOLD_FTR_MASK    GENMASK(1, 0)
 137 #define STM32_DMA_THRESHOLD_FTR_GET(n)  ((n) & STM32_DMA_THRESHOLD_FTR_MASK)
 138 
 139 enum stm32_dma_width {
 140         STM32_DMA_BYTE,
 141         STM32_DMA_HALF_WORD,
 142         STM32_DMA_WORD,
 143 };
 144 
 145 enum stm32_dma_burst_size {
 146         STM32_DMA_BURST_SINGLE,
 147         STM32_DMA_BURST_INCR4,
 148         STM32_DMA_BURST_INCR8,
 149         STM32_DMA_BURST_INCR16,
 150 };
 151 
 152 /**
 153  * struct stm32_dma_cfg - STM32 DMA custom configuration
 154  * @channel_id: channel ID
 155  * @request_line: DMA request
 156  * @stream_config: 32bit mask specifying the DMA channel configuration
 157  * @features: 32bit mask specifying the DMA Feature list
 158  */
 159 struct stm32_dma_cfg {
 160         u32 channel_id;
 161         u32 request_line;
 162         u32 stream_config;
 163         u32 features;
 164 };
 165 
 166 struct stm32_dma_chan_reg {
 167         u32 dma_lisr;
 168         u32 dma_hisr;
 169         u32 dma_lifcr;
 170         u32 dma_hifcr;
 171         u32 dma_scr;
 172         u32 dma_sndtr;
 173         u32 dma_spar;
 174         u32 dma_sm0ar;
 175         u32 dma_sm1ar;
 176         u32 dma_sfcr;
 177 };
 178 
 179 struct stm32_dma_sg_req {
 180         u32 len;
 181         struct stm32_dma_chan_reg chan_reg;
 182 };
 183 
 184 struct stm32_dma_desc {
 185         struct virt_dma_desc vdesc;
 186         bool cyclic;
 187         u32 num_sgs;
 188         struct stm32_dma_sg_req sg_req[];
 189 };
 190 
 191 struct stm32_dma_chan {
 192         struct virt_dma_chan vchan;
 193         bool config_init;
 194         bool busy;
 195         u32 id;
 196         u32 irq;
 197         struct stm32_dma_desc *desc;
 198         u32 next_sg;
 199         struct dma_slave_config dma_sconfig;
 200         struct stm32_dma_chan_reg chan_reg;
 201         u32 threshold;
 202         u32 mem_burst;
 203         u32 mem_width;
 204 };
 205 
 206 struct stm32_dma_device {
 207         struct dma_device ddev;
 208         void __iomem *base;
 209         struct clk *clk;
 210         struct reset_control *rst;
 211         bool mem2mem;
 212         struct stm32_dma_chan chan[STM32_DMA_MAX_CHANNELS];
 213 };
 214 
 215 static struct stm32_dma_device *stm32_dma_get_dev(struct stm32_dma_chan *chan)
 216 {
 217         return container_of(chan->vchan.chan.device, struct stm32_dma_device,
 218                             ddev);
 219 }
 220 
 221 static struct stm32_dma_chan *to_stm32_dma_chan(struct dma_chan *c)
 222 {
 223         return container_of(c, struct stm32_dma_chan, vchan.chan);
 224 }
 225 
 226 static struct stm32_dma_desc *to_stm32_dma_desc(struct virt_dma_desc *vdesc)
 227 {
 228         return container_of(vdesc, struct stm32_dma_desc, vdesc);
 229 }
 230 
 231 static struct device *chan2dev(struct stm32_dma_chan *chan)
 232 {
 233         return &chan->vchan.chan.dev->device;
 234 }
 235 
 236 static u32 stm32_dma_read(struct stm32_dma_device *dmadev, u32 reg)
 237 {
 238         return readl_relaxed(dmadev->base + reg);
 239 }
 240 
 241 static void stm32_dma_write(struct stm32_dma_device *dmadev, u32 reg, u32 val)
 242 {
 243         writel_relaxed(val, dmadev->base + reg);
 244 }
 245 
 246 static int stm32_dma_get_width(struct stm32_dma_chan *chan,
 247                                enum dma_slave_buswidth width)
 248 {
 249         switch (width) {
 250         case DMA_SLAVE_BUSWIDTH_1_BYTE:
 251                 return STM32_DMA_BYTE;
 252         case DMA_SLAVE_BUSWIDTH_2_BYTES:
 253                 return STM32_DMA_HALF_WORD;
 254         case DMA_SLAVE_BUSWIDTH_4_BYTES:
 255                 return STM32_DMA_WORD;
 256         default:
 257                 dev_err(chan2dev(chan), "Dma bus width not supported\n");
 258                 return -EINVAL;
 259         }
 260 }
 261 
 262 static enum dma_slave_buswidth stm32_dma_get_max_width(u32 buf_len,
 263                                                        u32 threshold)
 264 {
 265         enum dma_slave_buswidth max_width;
 266 
 267         if (threshold == STM32_DMA_FIFO_THRESHOLD_FULL)
 268                 max_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
 269         else
 270                 max_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 271 
 272         while ((buf_len < max_width  || buf_len % max_width) &&
 273                max_width > DMA_SLAVE_BUSWIDTH_1_BYTE)
 274                 max_width = max_width >> 1;
 275 
 276         return max_width;
 277 }
 278 
 279 static bool stm32_dma_fifo_threshold_is_allowed(u32 burst, u32 threshold,
 280                                                 enum dma_slave_buswidth width)
 281 {
 282         u32 remaining;
 283 
 284         if (width != DMA_SLAVE_BUSWIDTH_UNDEFINED) {
 285                 if (burst != 0) {
 286                         /*
 287                          * If number of beats fit in several whole bursts
 288                          * this configuration is allowed.
 289                          */
 290                         remaining = ((STM32_DMA_FIFO_SIZE / width) *
 291                                      (threshold + 1) / 4) % burst;
 292 
 293                         if (remaining == 0)
 294                                 return true;
 295                 } else {
 296                         return true;
 297                 }
 298         }
 299 
 300         return false;
 301 }
 302 
 303 static bool stm32_dma_is_burst_possible(u32 buf_len, u32 threshold)
 304 {
 305         /*
 306          * Buffer or period length has to be aligned on FIFO depth.
 307          * Otherwise bytes may be stuck within FIFO at buffer or period
 308          * length.
 309          */
 310         return ((buf_len % ((threshold + 1) * 4)) == 0);
 311 }
 312 
 313 static u32 stm32_dma_get_best_burst(u32 buf_len, u32 max_burst, u32 threshold,
 314                                     enum dma_slave_buswidth width)
 315 {
 316         u32 best_burst = max_burst;
 317 
 318         if (best_burst == 1 || !stm32_dma_is_burst_possible(buf_len, threshold))
 319                 return 0;
 320 
 321         while ((buf_len < best_burst * width && best_burst > 1) ||
 322                !stm32_dma_fifo_threshold_is_allowed(best_burst, threshold,
 323                                                     width)) {
 324                 if (best_burst > STM32_DMA_MIN_BURST)
 325                         best_burst = best_burst >> 1;
 326                 else
 327                         best_burst = 0;
 328         }
 329 
 330         return best_burst;
 331 }
 332 
 333 static int stm32_dma_get_burst(struct stm32_dma_chan *chan, u32 maxburst)
 334 {
 335         switch (maxburst) {
 336         case 0:
 337         case 1:
 338                 return STM32_DMA_BURST_SINGLE;
 339         case 4:
 340                 return STM32_DMA_BURST_INCR4;
 341         case 8:
 342                 return STM32_DMA_BURST_INCR8;
 343         case 16:
 344                 return STM32_DMA_BURST_INCR16;
 345         default:
 346                 dev_err(chan2dev(chan), "Dma burst size not supported\n");
 347                 return -EINVAL;
 348         }
 349 }
 350 
 351 static void stm32_dma_set_fifo_config(struct stm32_dma_chan *chan,
 352                                       u32 src_burst, u32 dst_burst)
 353 {
 354         chan->chan_reg.dma_sfcr &= ~STM32_DMA_SFCR_MASK;
 355         chan->chan_reg.dma_scr &= ~STM32_DMA_SCR_DMEIE;
 356 
 357         if (!src_burst && !dst_burst) {
 358                 /* Using direct mode */
 359                 chan->chan_reg.dma_scr |= STM32_DMA_SCR_DMEIE;
 360         } else {
 361                 /* Using FIFO mode */
 362                 chan->chan_reg.dma_sfcr |= STM32_DMA_SFCR_MASK;
 363         }
 364 }
 365 
 366 static int stm32_dma_slave_config(struct dma_chan *c,
 367                                   struct dma_slave_config *config)
 368 {
 369         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 370 
 371         memcpy(&chan->dma_sconfig, config, sizeof(*config));
 372 
 373         chan->config_init = true;
 374 
 375         return 0;
 376 }
 377 
 378 static u32 stm32_dma_irq_status(struct stm32_dma_chan *chan)
 379 {
 380         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 381         u32 flags, dma_isr;
 382 
 383         /*
 384          * Read "flags" from DMA_xISR register corresponding to the selected
 385          * DMA channel at the correct bit offset inside that register.
 386          *
 387          * If (ch % 4) is 2 or 3, left shift the mask by 16 bits.
 388          * If (ch % 4) is 1 or 3, additionally left shift the mask by 6 bits.
 389          */
 390 
 391         if (chan->id & 4)
 392                 dma_isr = stm32_dma_read(dmadev, STM32_DMA_HISR);
 393         else
 394                 dma_isr = stm32_dma_read(dmadev, STM32_DMA_LISR);
 395 
 396         flags = dma_isr >> (((chan->id & 2) << 3) | ((chan->id & 1) * 6));
 397 
 398         return flags & STM32_DMA_MASKI;
 399 }
 400 
 401 static void stm32_dma_irq_clear(struct stm32_dma_chan *chan, u32 flags)
 402 {
 403         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 404         u32 dma_ifcr;
 405 
 406         /*
 407          * Write "flags" to the DMA_xIFCR register corresponding to the selected
 408          * DMA channel at the correct bit offset inside that register.
 409          *
 410          * If (ch % 4) is 2 or 3, left shift the mask by 16 bits.
 411          * If (ch % 4) is 1 or 3, additionally left shift the mask by 6 bits.
 412          */
 413         flags &= STM32_DMA_MASKI;
 414         dma_ifcr = flags << (((chan->id & 2) << 3) | ((chan->id & 1) * 6));
 415 
 416         if (chan->id & 4)
 417                 stm32_dma_write(dmadev, STM32_DMA_HIFCR, dma_ifcr);
 418         else
 419                 stm32_dma_write(dmadev, STM32_DMA_LIFCR, dma_ifcr);
 420 }
 421 
 422 static int stm32_dma_disable_chan(struct stm32_dma_chan *chan)
 423 {
 424         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 425         unsigned long timeout = jiffies + msecs_to_jiffies(5000);
 426         u32 dma_scr, id;
 427 
 428         id = chan->id;
 429         dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id));
 430 
 431         if (dma_scr & STM32_DMA_SCR_EN) {
 432                 dma_scr &= ~STM32_DMA_SCR_EN;
 433                 stm32_dma_write(dmadev, STM32_DMA_SCR(id), dma_scr);
 434 
 435                 do {
 436                         dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id));
 437                         dma_scr &= STM32_DMA_SCR_EN;
 438                         if (!dma_scr)
 439                                 break;
 440 
 441                         if (time_after_eq(jiffies, timeout)) {
 442                                 dev_err(chan2dev(chan), "%s: timeout!\n",
 443                                         __func__);
 444                                 return -EBUSY;
 445                         }
 446                         cond_resched();
 447                 } while (1);
 448         }
 449 
 450         return 0;
 451 }
 452 
 453 static void stm32_dma_stop(struct stm32_dma_chan *chan)
 454 {
 455         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 456         u32 dma_scr, dma_sfcr, status;
 457         int ret;
 458 
 459         /* Disable interrupts */
 460         dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id));
 461         dma_scr &= ~STM32_DMA_SCR_IRQ_MASK;
 462         stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), dma_scr);
 463         dma_sfcr = stm32_dma_read(dmadev, STM32_DMA_SFCR(chan->id));
 464         dma_sfcr &= ~STM32_DMA_SFCR_FEIE;
 465         stm32_dma_write(dmadev, STM32_DMA_SFCR(chan->id), dma_sfcr);
 466 
 467         /* Disable DMA */
 468         ret = stm32_dma_disable_chan(chan);
 469         if (ret < 0)
 470                 return;
 471 
 472         /* Clear interrupt status if it is there */
 473         status = stm32_dma_irq_status(chan);
 474         if (status) {
 475                 dev_dbg(chan2dev(chan), "%s(): clearing interrupt: 0x%08x\n",
 476                         __func__, status);
 477                 stm32_dma_irq_clear(chan, status);
 478         }
 479 
 480         chan->busy = false;
 481 }
 482 
 483 static int stm32_dma_terminate_all(struct dma_chan *c)
 484 {
 485         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 486         unsigned long flags;
 487         LIST_HEAD(head);
 488 
 489         spin_lock_irqsave(&chan->vchan.lock, flags);
 490 
 491         if (chan->busy) {
 492                 stm32_dma_stop(chan);
 493                 chan->desc = NULL;
 494         }
 495 
 496         vchan_get_all_descriptors(&chan->vchan, &head);
 497         spin_unlock_irqrestore(&chan->vchan.lock, flags);
 498         vchan_dma_desc_free_list(&chan->vchan, &head);
 499 
 500         return 0;
 501 }
 502 
 503 static void stm32_dma_synchronize(struct dma_chan *c)
 504 {
 505         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 506 
 507         vchan_synchronize(&chan->vchan);
 508 }
 509 
 510 static void stm32_dma_dump_reg(struct stm32_dma_chan *chan)
 511 {
 512         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 513         u32 scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id));
 514         u32 ndtr = stm32_dma_read(dmadev, STM32_DMA_SNDTR(chan->id));
 515         u32 spar = stm32_dma_read(dmadev, STM32_DMA_SPAR(chan->id));
 516         u32 sm0ar = stm32_dma_read(dmadev, STM32_DMA_SM0AR(chan->id));
 517         u32 sm1ar = stm32_dma_read(dmadev, STM32_DMA_SM1AR(chan->id));
 518         u32 sfcr = stm32_dma_read(dmadev, STM32_DMA_SFCR(chan->id));
 519 
 520         dev_dbg(chan2dev(chan), "SCR:   0x%08x\n", scr);
 521         dev_dbg(chan2dev(chan), "NDTR:  0x%08x\n", ndtr);
 522         dev_dbg(chan2dev(chan), "SPAR:  0x%08x\n", spar);
 523         dev_dbg(chan2dev(chan), "SM0AR: 0x%08x\n", sm0ar);
 524         dev_dbg(chan2dev(chan), "SM1AR: 0x%08x\n", sm1ar);
 525         dev_dbg(chan2dev(chan), "SFCR:  0x%08x\n", sfcr);
 526 }
 527 
 528 static void stm32_dma_configure_next_sg(struct stm32_dma_chan *chan);
 529 
 530 static void stm32_dma_start_transfer(struct stm32_dma_chan *chan)
 531 {
 532         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 533         struct virt_dma_desc *vdesc;
 534         struct stm32_dma_sg_req *sg_req;
 535         struct stm32_dma_chan_reg *reg;
 536         u32 status;
 537         int ret;
 538 
 539         ret = stm32_dma_disable_chan(chan);
 540         if (ret < 0)
 541                 return;
 542 
 543         if (!chan->desc) {
 544                 vdesc = vchan_next_desc(&chan->vchan);
 545                 if (!vdesc)
 546                         return;
 547 
 548                 chan->desc = to_stm32_dma_desc(vdesc);
 549                 chan->next_sg = 0;
 550         }
 551 
 552         if (chan->next_sg == chan->desc->num_sgs)
 553                 chan->next_sg = 0;
 554 
 555         sg_req = &chan->desc->sg_req[chan->next_sg];
 556         reg = &sg_req->chan_reg;
 557 
 558         stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), reg->dma_scr);
 559         stm32_dma_write(dmadev, STM32_DMA_SPAR(chan->id), reg->dma_spar);
 560         stm32_dma_write(dmadev, STM32_DMA_SM0AR(chan->id), reg->dma_sm0ar);
 561         stm32_dma_write(dmadev, STM32_DMA_SFCR(chan->id), reg->dma_sfcr);
 562         stm32_dma_write(dmadev, STM32_DMA_SM1AR(chan->id), reg->dma_sm1ar);
 563         stm32_dma_write(dmadev, STM32_DMA_SNDTR(chan->id), reg->dma_sndtr);
 564 
 565         chan->next_sg++;
 566 
 567         /* Clear interrupt status if it is there */
 568         status = stm32_dma_irq_status(chan);
 569         if (status)
 570                 stm32_dma_irq_clear(chan, status);
 571 
 572         if (chan->desc->cyclic)
 573                 stm32_dma_configure_next_sg(chan);
 574 
 575         stm32_dma_dump_reg(chan);
 576 
 577         /* Start DMA */
 578         reg->dma_scr |= STM32_DMA_SCR_EN;
 579         stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), reg->dma_scr);
 580 
 581         chan->busy = true;
 582 
 583         dev_dbg(chan2dev(chan), "vchan %pK: started\n", &chan->vchan);
 584 }
 585 
 586 static void stm32_dma_configure_next_sg(struct stm32_dma_chan *chan)
 587 {
 588         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 589         struct stm32_dma_sg_req *sg_req;
 590         u32 dma_scr, dma_sm0ar, dma_sm1ar, id;
 591 
 592         id = chan->id;
 593         dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id));
 594 
 595         if (dma_scr & STM32_DMA_SCR_DBM) {
 596                 if (chan->next_sg == chan->desc->num_sgs)
 597                         chan->next_sg = 0;
 598 
 599                 sg_req = &chan->desc->sg_req[chan->next_sg];
 600 
 601                 if (dma_scr & STM32_DMA_SCR_CT) {
 602                         dma_sm0ar = sg_req->chan_reg.dma_sm0ar;
 603                         stm32_dma_write(dmadev, STM32_DMA_SM0AR(id), dma_sm0ar);
 604                         dev_dbg(chan2dev(chan), "CT=1 <=> SM0AR: 0x%08x\n",
 605                                 stm32_dma_read(dmadev, STM32_DMA_SM0AR(id)));
 606                 } else {
 607                         dma_sm1ar = sg_req->chan_reg.dma_sm1ar;
 608                         stm32_dma_write(dmadev, STM32_DMA_SM1AR(id), dma_sm1ar);
 609                         dev_dbg(chan2dev(chan), "CT=0 <=> SM1AR: 0x%08x\n",
 610                                 stm32_dma_read(dmadev, STM32_DMA_SM1AR(id)));
 611                 }
 612         }
 613 }
 614 
 615 static void stm32_dma_handle_chan_done(struct stm32_dma_chan *chan)
 616 {
 617         if (chan->desc) {
 618                 if (chan->desc->cyclic) {
 619                         vchan_cyclic_callback(&chan->desc->vdesc);
 620                         chan->next_sg++;
 621                         stm32_dma_configure_next_sg(chan);
 622                 } else {
 623                         chan->busy = false;
 624                         if (chan->next_sg == chan->desc->num_sgs) {
 625                                 list_del(&chan->desc->vdesc.node);
 626                                 vchan_cookie_complete(&chan->desc->vdesc);
 627                                 chan->desc = NULL;
 628                         }
 629                         stm32_dma_start_transfer(chan);
 630                 }
 631         }
 632 }
 633 
 634 static irqreturn_t stm32_dma_chan_irq(int irq, void *devid)
 635 {
 636         struct stm32_dma_chan *chan = devid;
 637         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 638         u32 status, scr, sfcr;
 639 
 640         spin_lock(&chan->vchan.lock);
 641 
 642         status = stm32_dma_irq_status(chan);
 643         scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id));
 644         sfcr = stm32_dma_read(dmadev, STM32_DMA_SFCR(chan->id));
 645 
 646         if (status & STM32_DMA_TCI) {
 647                 stm32_dma_irq_clear(chan, STM32_DMA_TCI);
 648                 if (scr & STM32_DMA_SCR_TCIE)
 649                         stm32_dma_handle_chan_done(chan);
 650                 status &= ~STM32_DMA_TCI;
 651         }
 652         if (status & STM32_DMA_HTI) {
 653                 stm32_dma_irq_clear(chan, STM32_DMA_HTI);
 654                 status &= ~STM32_DMA_HTI;
 655         }
 656         if (status & STM32_DMA_FEI) {
 657                 stm32_dma_irq_clear(chan, STM32_DMA_FEI);
 658                 status &= ~STM32_DMA_FEI;
 659                 if (sfcr & STM32_DMA_SFCR_FEIE) {
 660                         if (!(scr & STM32_DMA_SCR_EN))
 661                                 dev_err(chan2dev(chan), "FIFO Error\n");
 662                         else
 663                                 dev_dbg(chan2dev(chan), "FIFO over/underrun\n");
 664                 }
 665         }
 666         if (status) {
 667                 stm32_dma_irq_clear(chan, status);
 668                 dev_err(chan2dev(chan), "DMA error: status=0x%08x\n", status);
 669                 if (!(scr & STM32_DMA_SCR_EN))
 670                         dev_err(chan2dev(chan), "chan disabled by HW\n");
 671         }
 672 
 673         spin_unlock(&chan->vchan.lock);
 674 
 675         return IRQ_HANDLED;
 676 }
 677 
 678 static void stm32_dma_issue_pending(struct dma_chan *c)
 679 {
 680         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 681         unsigned long flags;
 682 
 683         spin_lock_irqsave(&chan->vchan.lock, flags);
 684         if (vchan_issue_pending(&chan->vchan) && !chan->desc && !chan->busy) {
 685                 dev_dbg(chan2dev(chan), "vchan %pK: issued\n", &chan->vchan);
 686                 stm32_dma_start_transfer(chan);
 687 
 688         }
 689         spin_unlock_irqrestore(&chan->vchan.lock, flags);
 690 }
 691 
 692 static int stm32_dma_set_xfer_param(struct stm32_dma_chan *chan,
 693                                     enum dma_transfer_direction direction,
 694                                     enum dma_slave_buswidth *buswidth,
 695                                     u32 buf_len)
 696 {
 697         enum dma_slave_buswidth src_addr_width, dst_addr_width;
 698         int src_bus_width, dst_bus_width;
 699         int src_burst_size, dst_burst_size;
 700         u32 src_maxburst, dst_maxburst, src_best_burst, dst_best_burst;
 701         u32 dma_scr, threshold;
 702 
 703         src_addr_width = chan->dma_sconfig.src_addr_width;
 704         dst_addr_width = chan->dma_sconfig.dst_addr_width;
 705         src_maxburst = chan->dma_sconfig.src_maxburst;
 706         dst_maxburst = chan->dma_sconfig.dst_maxburst;
 707         threshold = chan->threshold;
 708 
 709         switch (direction) {
 710         case DMA_MEM_TO_DEV:
 711                 /* Set device data size */
 712                 dst_bus_width = stm32_dma_get_width(chan, dst_addr_width);
 713                 if (dst_bus_width < 0)
 714                         return dst_bus_width;
 715 
 716                 /* Set device burst size */
 717                 dst_best_burst = stm32_dma_get_best_burst(buf_len,
 718                                                           dst_maxburst,
 719                                                           threshold,
 720                                                           dst_addr_width);
 721 
 722                 dst_burst_size = stm32_dma_get_burst(chan, dst_best_burst);
 723                 if (dst_burst_size < 0)
 724                         return dst_burst_size;
 725 
 726                 /* Set memory data size */
 727                 src_addr_width = stm32_dma_get_max_width(buf_len, threshold);
 728                 chan->mem_width = src_addr_width;
 729                 src_bus_width = stm32_dma_get_width(chan, src_addr_width);
 730                 if (src_bus_width < 0)
 731                         return src_bus_width;
 732 
 733                 /* Set memory burst size */
 734                 src_maxburst = STM32_DMA_MAX_BURST;
 735                 src_best_burst = stm32_dma_get_best_burst(buf_len,
 736                                                           src_maxburst,
 737                                                           threshold,
 738                                                           src_addr_width);
 739                 src_burst_size = stm32_dma_get_burst(chan, src_best_burst);
 740                 if (src_burst_size < 0)
 741                         return src_burst_size;
 742 
 743                 dma_scr = STM32_DMA_SCR_DIR(STM32_DMA_MEM_TO_DEV) |
 744                         STM32_DMA_SCR_PSIZE(dst_bus_width) |
 745                         STM32_DMA_SCR_MSIZE(src_bus_width) |
 746                         STM32_DMA_SCR_PBURST(dst_burst_size) |
 747                         STM32_DMA_SCR_MBURST(src_burst_size);
 748 
 749                 /* Set FIFO threshold */
 750                 chan->chan_reg.dma_sfcr &= ~STM32_DMA_SFCR_FTH_MASK;
 751                 chan->chan_reg.dma_sfcr |= STM32_DMA_SFCR_FTH(threshold);
 752 
 753                 /* Set peripheral address */
 754                 chan->chan_reg.dma_spar = chan->dma_sconfig.dst_addr;
 755                 *buswidth = dst_addr_width;
 756                 break;
 757 
 758         case DMA_DEV_TO_MEM:
 759                 /* Set device data size */
 760                 src_bus_width = stm32_dma_get_width(chan, src_addr_width);
 761                 if (src_bus_width < 0)
 762                         return src_bus_width;
 763 
 764                 /* Set device burst size */
 765                 src_best_burst = stm32_dma_get_best_burst(buf_len,
 766                                                           src_maxburst,
 767                                                           threshold,
 768                                                           src_addr_width);
 769                 chan->mem_burst = src_best_burst;
 770                 src_burst_size = stm32_dma_get_burst(chan, src_best_burst);
 771                 if (src_burst_size < 0)
 772                         return src_burst_size;
 773 
 774                 /* Set memory data size */
 775                 dst_addr_width = stm32_dma_get_max_width(buf_len, threshold);
 776                 chan->mem_width = dst_addr_width;
 777                 dst_bus_width = stm32_dma_get_width(chan, dst_addr_width);
 778                 if (dst_bus_width < 0)
 779                         return dst_bus_width;
 780 
 781                 /* Set memory burst size */
 782                 dst_maxburst = STM32_DMA_MAX_BURST;
 783                 dst_best_burst = stm32_dma_get_best_burst(buf_len,
 784                                                           dst_maxburst,
 785                                                           threshold,
 786                                                           dst_addr_width);
 787                 chan->mem_burst = dst_best_burst;
 788                 dst_burst_size = stm32_dma_get_burst(chan, dst_best_burst);
 789                 if (dst_burst_size < 0)
 790                         return dst_burst_size;
 791 
 792                 dma_scr = STM32_DMA_SCR_DIR(STM32_DMA_DEV_TO_MEM) |
 793                         STM32_DMA_SCR_PSIZE(src_bus_width) |
 794                         STM32_DMA_SCR_MSIZE(dst_bus_width) |
 795                         STM32_DMA_SCR_PBURST(src_burst_size) |
 796                         STM32_DMA_SCR_MBURST(dst_burst_size);
 797 
 798                 /* Set FIFO threshold */
 799                 chan->chan_reg.dma_sfcr &= ~STM32_DMA_SFCR_FTH_MASK;
 800                 chan->chan_reg.dma_sfcr |= STM32_DMA_SFCR_FTH(threshold);
 801 
 802                 /* Set peripheral address */
 803                 chan->chan_reg.dma_spar = chan->dma_sconfig.src_addr;
 804                 *buswidth = chan->dma_sconfig.src_addr_width;
 805                 break;
 806 
 807         default:
 808                 dev_err(chan2dev(chan), "Dma direction is not supported\n");
 809                 return -EINVAL;
 810         }
 811 
 812         stm32_dma_set_fifo_config(chan, src_best_burst, dst_best_burst);
 813 
 814         /* Set DMA control register */
 815         chan->chan_reg.dma_scr &= ~(STM32_DMA_SCR_DIR_MASK |
 816                         STM32_DMA_SCR_PSIZE_MASK | STM32_DMA_SCR_MSIZE_MASK |
 817                         STM32_DMA_SCR_PBURST_MASK | STM32_DMA_SCR_MBURST_MASK);
 818         chan->chan_reg.dma_scr |= dma_scr;
 819 
 820         return 0;
 821 }
 822 
 823 static void stm32_dma_clear_reg(struct stm32_dma_chan_reg *regs)
 824 {
 825         memset(regs, 0, sizeof(struct stm32_dma_chan_reg));
 826 }
 827 
 828 static struct dma_async_tx_descriptor *stm32_dma_prep_slave_sg(
 829         struct dma_chan *c, struct scatterlist *sgl,
 830         u32 sg_len, enum dma_transfer_direction direction,
 831         unsigned long flags, void *context)
 832 {
 833         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 834         struct stm32_dma_desc *desc;
 835         struct scatterlist *sg;
 836         enum dma_slave_buswidth buswidth;
 837         u32 nb_data_items;
 838         int i, ret;
 839 
 840         if (!chan->config_init) {
 841                 dev_err(chan2dev(chan), "dma channel is not configured\n");
 842                 return NULL;
 843         }
 844 
 845         if (sg_len < 1) {
 846                 dev_err(chan2dev(chan), "Invalid segment length %d\n", sg_len);
 847                 return NULL;
 848         }
 849 
 850         desc = kzalloc(struct_size(desc, sg_req, sg_len), GFP_NOWAIT);
 851         if (!desc)
 852                 return NULL;
 853 
 854         /* Set peripheral flow controller */
 855         if (chan->dma_sconfig.device_fc)
 856                 chan->chan_reg.dma_scr |= STM32_DMA_SCR_PFCTRL;
 857         else
 858                 chan->chan_reg.dma_scr &= ~STM32_DMA_SCR_PFCTRL;
 859 
 860         for_each_sg(sgl, sg, sg_len, i) {
 861                 ret = stm32_dma_set_xfer_param(chan, direction, &buswidth,
 862                                                sg_dma_len(sg));
 863                 if (ret < 0)
 864                         goto err;
 865 
 866                 desc->sg_req[i].len = sg_dma_len(sg);
 867 
 868                 nb_data_items = desc->sg_req[i].len / buswidth;
 869                 if (nb_data_items > STM32_DMA_ALIGNED_MAX_DATA_ITEMS) {
 870                         dev_err(chan2dev(chan), "nb items not supported\n");
 871                         goto err;
 872                 }
 873 
 874                 stm32_dma_clear_reg(&desc->sg_req[i].chan_reg);
 875                 desc->sg_req[i].chan_reg.dma_scr = chan->chan_reg.dma_scr;
 876                 desc->sg_req[i].chan_reg.dma_sfcr = chan->chan_reg.dma_sfcr;
 877                 desc->sg_req[i].chan_reg.dma_spar = chan->chan_reg.dma_spar;
 878                 desc->sg_req[i].chan_reg.dma_sm0ar = sg_dma_address(sg);
 879                 desc->sg_req[i].chan_reg.dma_sm1ar = sg_dma_address(sg);
 880                 desc->sg_req[i].chan_reg.dma_sndtr = nb_data_items;
 881         }
 882 
 883         desc->num_sgs = sg_len;
 884         desc->cyclic = false;
 885 
 886         return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
 887 
 888 err:
 889         kfree(desc);
 890         return NULL;
 891 }
 892 
 893 static struct dma_async_tx_descriptor *stm32_dma_prep_dma_cyclic(
 894         struct dma_chan *c, dma_addr_t buf_addr, size_t buf_len,
 895         size_t period_len, enum dma_transfer_direction direction,
 896         unsigned long flags)
 897 {
 898         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 899         struct stm32_dma_desc *desc;
 900         enum dma_slave_buswidth buswidth;
 901         u32 num_periods, nb_data_items;
 902         int i, ret;
 903 
 904         if (!buf_len || !period_len) {
 905                 dev_err(chan2dev(chan), "Invalid buffer/period len\n");
 906                 return NULL;
 907         }
 908 
 909         if (!chan->config_init) {
 910                 dev_err(chan2dev(chan), "dma channel is not configured\n");
 911                 return NULL;
 912         }
 913 
 914         if (buf_len % period_len) {
 915                 dev_err(chan2dev(chan), "buf_len not multiple of period_len\n");
 916                 return NULL;
 917         }
 918 
 919         /*
 920          * We allow to take more number of requests till DMA is
 921          * not started. The driver will loop over all requests.
 922          * Once DMA is started then new requests can be queued only after
 923          * terminating the DMA.
 924          */
 925         if (chan->busy) {
 926                 dev_err(chan2dev(chan), "Request not allowed when dma busy\n");
 927                 return NULL;
 928         }
 929 
 930         ret = stm32_dma_set_xfer_param(chan, direction, &buswidth, period_len);
 931         if (ret < 0)
 932                 return NULL;
 933 
 934         nb_data_items = period_len / buswidth;
 935         if (nb_data_items > STM32_DMA_ALIGNED_MAX_DATA_ITEMS) {
 936                 dev_err(chan2dev(chan), "number of items not supported\n");
 937                 return NULL;
 938         }
 939 
 940         /*  Enable Circular mode or double buffer mode */
 941         if (buf_len == period_len)
 942                 chan->chan_reg.dma_scr |= STM32_DMA_SCR_CIRC;
 943         else
 944                 chan->chan_reg.dma_scr |= STM32_DMA_SCR_DBM;
 945 
 946         /* Clear periph ctrl if client set it */
 947         chan->chan_reg.dma_scr &= ~STM32_DMA_SCR_PFCTRL;
 948 
 949         num_periods = buf_len / period_len;
 950 
 951         desc = kzalloc(struct_size(desc, sg_req, num_periods), GFP_NOWAIT);
 952         if (!desc)
 953                 return NULL;
 954 
 955         for (i = 0; i < num_periods; i++) {
 956                 desc->sg_req[i].len = period_len;
 957 
 958                 stm32_dma_clear_reg(&desc->sg_req[i].chan_reg);
 959                 desc->sg_req[i].chan_reg.dma_scr = chan->chan_reg.dma_scr;
 960                 desc->sg_req[i].chan_reg.dma_sfcr = chan->chan_reg.dma_sfcr;
 961                 desc->sg_req[i].chan_reg.dma_spar = chan->chan_reg.dma_spar;
 962                 desc->sg_req[i].chan_reg.dma_sm0ar = buf_addr;
 963                 desc->sg_req[i].chan_reg.dma_sm1ar = buf_addr;
 964                 desc->sg_req[i].chan_reg.dma_sndtr = nb_data_items;
 965                 buf_addr += period_len;
 966         }
 967 
 968         desc->num_sgs = num_periods;
 969         desc->cyclic = true;
 970 
 971         return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
 972 }
 973 
 974 static struct dma_async_tx_descriptor *stm32_dma_prep_dma_memcpy(
 975         struct dma_chan *c, dma_addr_t dest,
 976         dma_addr_t src, size_t len, unsigned long flags)
 977 {
 978         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 979         enum dma_slave_buswidth max_width;
 980         struct stm32_dma_desc *desc;
 981         size_t xfer_count, offset;
 982         u32 num_sgs, best_burst, dma_burst, threshold;
 983         int i;
 984 
 985         num_sgs = DIV_ROUND_UP(len, STM32_DMA_ALIGNED_MAX_DATA_ITEMS);
 986         desc = kzalloc(struct_size(desc, sg_req, num_sgs), GFP_NOWAIT);
 987         if (!desc)
 988                 return NULL;
 989 
 990         threshold = chan->threshold;
 991 
 992         for (offset = 0, i = 0; offset < len; offset += xfer_count, i++) {
 993                 xfer_count = min_t(size_t, len - offset,
 994                                    STM32_DMA_ALIGNED_MAX_DATA_ITEMS);
 995 
 996                 /* Compute best burst size */
 997                 max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
 998                 best_burst = stm32_dma_get_best_burst(len, STM32_DMA_MAX_BURST,
 999                                                       threshold, max_width);
1000                 dma_burst = stm32_dma_get_burst(chan, best_burst);
1001 
1002                 stm32_dma_clear_reg(&desc->sg_req[i].chan_reg);
1003                 desc->sg_req[i].chan_reg.dma_scr =
1004                         STM32_DMA_SCR_DIR(STM32_DMA_MEM_TO_MEM) |
1005                         STM32_DMA_SCR_PBURST(dma_burst) |
1006                         STM32_DMA_SCR_MBURST(dma_burst) |
1007                         STM32_DMA_SCR_MINC |
1008                         STM32_DMA_SCR_PINC |
1009                         STM32_DMA_SCR_TCIE |
1010                         STM32_DMA_SCR_TEIE;
1011                 desc->sg_req[i].chan_reg.dma_sfcr |= STM32_DMA_SFCR_MASK;
1012                 desc->sg_req[i].chan_reg.dma_sfcr |=
1013                         STM32_DMA_SFCR_FTH(threshold);
1014                 desc->sg_req[i].chan_reg.dma_spar = src + offset;
1015                 desc->sg_req[i].chan_reg.dma_sm0ar = dest + offset;
1016                 desc->sg_req[i].chan_reg.dma_sndtr = xfer_count;
1017                 desc->sg_req[i].len = xfer_count;
1018         }
1019 
1020         desc->num_sgs = num_sgs;
1021         desc->cyclic = false;
1022 
1023         return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
1024 }
1025 
1026 static u32 stm32_dma_get_remaining_bytes(struct stm32_dma_chan *chan)
1027 {
1028         u32 dma_scr, width, ndtr;
1029         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
1030 
1031         dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id));
1032         width = STM32_DMA_SCR_PSIZE_GET(dma_scr);
1033         ndtr = stm32_dma_read(dmadev, STM32_DMA_SNDTR(chan->id));
1034 
1035         return ndtr << width;
1036 }
1037 
1038 /**
1039  * stm32_dma_is_current_sg - check that expected sg_req is currently transferred
1040  * @chan: dma channel
1041  *
1042  * This function called when IRQ are disable, checks that the hardware has not
1043  * switched on the next transfer in double buffer mode. The test is done by
1044  * comparing the next_sg memory address with the hardware related register
1045  * (based on CT bit value).
1046  *
1047  * Returns true if expected current transfer is still running or double
1048  * buffer mode is not activated.
1049  */
1050 static bool stm32_dma_is_current_sg(struct stm32_dma_chan *chan)
1051 {
1052         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
1053         struct stm32_dma_sg_req *sg_req;
1054         u32 dma_scr, dma_smar, id;
1055 
1056         id = chan->id;
1057         dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id));
1058 
1059         if (!(dma_scr & STM32_DMA_SCR_DBM))
1060                 return true;
1061 
1062         sg_req = &chan->desc->sg_req[chan->next_sg];
1063 
1064         if (dma_scr & STM32_DMA_SCR_CT) {
1065                 dma_smar = stm32_dma_read(dmadev, STM32_DMA_SM0AR(id));
1066                 return (dma_smar == sg_req->chan_reg.dma_sm0ar);
1067         }
1068 
1069         dma_smar = stm32_dma_read(dmadev, STM32_DMA_SM1AR(id));
1070 
1071         return (dma_smar == sg_req->chan_reg.dma_sm1ar);
1072 }
1073 
1074 static size_t stm32_dma_desc_residue(struct stm32_dma_chan *chan,
1075                                      struct stm32_dma_desc *desc,
1076                                      u32 next_sg)
1077 {
1078         u32 modulo, burst_size;
1079         u32 residue;
1080         u32 n_sg = next_sg;
1081         struct stm32_dma_sg_req *sg_req = &chan->desc->sg_req[chan->next_sg];
1082         int i;
1083 
1084         /*
1085          * Calculate the residue means compute the descriptors
1086          * information:
1087          * - the sg_req currently transferred
1088          * - the Hardware remaining position in this sg (NDTR bits field).
1089          *
1090          * A race condition may occur if DMA is running in cyclic or double
1091          * buffer mode, since the DMA register are automatically reloaded at end
1092          * of period transfer. The hardware may have switched to the next
1093          * transfer (CT bit updated) just before the position (SxNDTR reg) is
1094          * read.
1095          * In this case the SxNDTR reg could (or not) correspond to the new
1096          * transfer position, and not the expected one.
1097          * The strategy implemented in the stm32 driver is to:
1098          *  - read the SxNDTR register
1099          *  - crosscheck that hardware is still in current transfer.
1100          * In case of switch, we can assume that the DMA is at the beginning of
1101          * the next transfer. So we approximate the residue in consequence, by
1102          * pointing on the beginning of next transfer.
1103          *
1104          * This race condition doesn't apply for none cyclic mode, as double
1105          * buffer is not used. In such situation registers are updated by the
1106          * software.
1107          */
1108 
1109         residue = stm32_dma_get_remaining_bytes(chan);
1110 
1111         if (!stm32_dma_is_current_sg(chan)) {
1112                 n_sg++;
1113                 if (n_sg == chan->desc->num_sgs)
1114                         n_sg = 0;
1115                 residue = sg_req->len;
1116         }
1117 
1118         /*
1119          * In cyclic mode, for the last period, residue = remaining bytes
1120          * from NDTR,
1121          * else for all other periods in cyclic mode, and in sg mode,
1122          * residue = remaining bytes from NDTR + remaining
1123          * periods/sg to be transferred
1124          */
1125         if (!chan->desc->cyclic || n_sg != 0)
1126                 for (i = n_sg; i < desc->num_sgs; i++)
1127                         residue += desc->sg_req[i].len;
1128 
1129         if (!chan->mem_burst)
1130                 return residue;
1131 
1132         burst_size = chan->mem_burst * chan->mem_width;
1133         modulo = residue % burst_size;
1134         if (modulo)
1135                 residue = residue - modulo + burst_size;
1136 
1137         return residue;
1138 }
1139 
1140 static enum dma_status stm32_dma_tx_status(struct dma_chan *c,
1141                                            dma_cookie_t cookie,
1142                                            struct dma_tx_state *state)
1143 {
1144         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
1145         struct virt_dma_desc *vdesc;
1146         enum dma_status status;
1147         unsigned long flags;
1148         u32 residue = 0;
1149 
1150         status = dma_cookie_status(c, cookie, state);
1151         if (status == DMA_COMPLETE || !state)
1152                 return status;
1153 
1154         spin_lock_irqsave(&chan->vchan.lock, flags);
1155         vdesc = vchan_find_desc(&chan->vchan, cookie);
1156         if (chan->desc && cookie == chan->desc->vdesc.tx.cookie)
1157                 residue = stm32_dma_desc_residue(chan, chan->desc,
1158                                                  chan->next_sg);
1159         else if (vdesc)
1160                 residue = stm32_dma_desc_residue(chan,
1161                                                  to_stm32_dma_desc(vdesc), 0);
1162         dma_set_residue(state, residue);
1163 
1164         spin_unlock_irqrestore(&chan->vchan.lock, flags);
1165 
1166         return status;
1167 }
1168 
1169 static int stm32_dma_alloc_chan_resources(struct dma_chan *c)
1170 {
1171         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
1172         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
1173         int ret;
1174 
1175         chan->config_init = false;
1176 
1177         ret = pm_runtime_get_sync(dmadev->ddev.dev);
1178         if (ret < 0)
1179                 return ret;
1180 
1181         ret = stm32_dma_disable_chan(chan);
1182         if (ret < 0)
1183                 pm_runtime_put(dmadev->ddev.dev);
1184 
1185         return ret;
1186 }
1187 
1188 static void stm32_dma_free_chan_resources(struct dma_chan *c)
1189 {
1190         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
1191         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
1192         unsigned long flags;
1193 
1194         dev_dbg(chan2dev(chan), "Freeing channel %d\n", chan->id);
1195 
1196         if (chan->busy) {
1197                 spin_lock_irqsave(&chan->vchan.lock, flags);
1198                 stm32_dma_stop(chan);
1199                 chan->desc = NULL;
1200                 spin_unlock_irqrestore(&chan->vchan.lock, flags);
1201         }
1202 
1203         pm_runtime_put(dmadev->ddev.dev);
1204 
1205         vchan_free_chan_resources(to_virt_chan(c));
1206 }
1207 
1208 static void stm32_dma_desc_free(struct virt_dma_desc *vdesc)
1209 {
1210         kfree(container_of(vdesc, struct stm32_dma_desc, vdesc));
1211 }
1212 
1213 static void stm32_dma_set_config(struct stm32_dma_chan *chan,
1214                                  struct stm32_dma_cfg *cfg)
1215 {
1216         stm32_dma_clear_reg(&chan->chan_reg);
1217 
1218         chan->chan_reg.dma_scr = cfg->stream_config & STM32_DMA_SCR_CFG_MASK;
1219         chan->chan_reg.dma_scr |= STM32_DMA_SCR_REQ(cfg->request_line);
1220 
1221         /* Enable Interrupts  */
1222         chan->chan_reg.dma_scr |= STM32_DMA_SCR_TEIE | STM32_DMA_SCR_TCIE;
1223 
1224         chan->threshold = STM32_DMA_THRESHOLD_FTR_GET(cfg->features);
1225 }
1226 
1227 static struct dma_chan *stm32_dma_of_xlate(struct of_phandle_args *dma_spec,
1228                                            struct of_dma *ofdma)
1229 {
1230         struct stm32_dma_device *dmadev = ofdma->of_dma_data;
1231         struct device *dev = dmadev->ddev.dev;
1232         struct stm32_dma_cfg cfg;
1233         struct stm32_dma_chan *chan;
1234         struct dma_chan *c;
1235 
1236         if (dma_spec->args_count < 4) {
1237                 dev_err(dev, "Bad number of cells\n");
1238                 return NULL;
1239         }
1240 
1241         cfg.channel_id = dma_spec->args[0];
1242         cfg.request_line = dma_spec->args[1];
1243         cfg.stream_config = dma_spec->args[2];
1244         cfg.features = dma_spec->args[3];
1245 
1246         if (cfg.channel_id >= STM32_DMA_MAX_CHANNELS ||
1247             cfg.request_line >= STM32_DMA_MAX_REQUEST_ID) {
1248                 dev_err(dev, "Bad channel and/or request id\n");
1249                 return NULL;
1250         }
1251 
1252         chan = &dmadev->chan[cfg.channel_id];
1253 
1254         c = dma_get_slave_channel(&chan->vchan.chan);
1255         if (!c) {
1256                 dev_err(dev, "No more channels available\n");
1257                 return NULL;
1258         }
1259 
1260         stm32_dma_set_config(chan, &cfg);
1261 
1262         return c;
1263 }
1264 
1265 static const struct of_device_id stm32_dma_of_match[] = {
1266         { .compatible = "st,stm32-dma", },
1267         { /* sentinel */ },
1268 };
1269 MODULE_DEVICE_TABLE(of, stm32_dma_of_match);
1270 
1271 static int stm32_dma_probe(struct platform_device *pdev)
1272 {
1273         struct stm32_dma_chan *chan;
1274         struct stm32_dma_device *dmadev;
1275         struct dma_device *dd;
1276         const struct of_device_id *match;
1277         struct resource *res;
1278         int i, ret;
1279 
1280         match = of_match_device(stm32_dma_of_match, &pdev->dev);
1281         if (!match) {
1282                 dev_err(&pdev->dev, "Error: No device match found\n");
1283                 return -ENODEV;
1284         }
1285 
1286         dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev), GFP_KERNEL);
1287         if (!dmadev)
1288                 return -ENOMEM;
1289 
1290         dd = &dmadev->ddev;
1291 
1292         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1293         dmadev->base = devm_ioremap_resource(&pdev->dev, res);
1294         if (IS_ERR(dmadev->base))
1295                 return PTR_ERR(dmadev->base);
1296 
1297         dmadev->clk = devm_clk_get(&pdev->dev, NULL);
1298         if (IS_ERR(dmadev->clk)) {
1299                 dev_err(&pdev->dev, "Error: Missing controller clock\n");
1300                 return PTR_ERR(dmadev->clk);
1301         }
1302 
1303         ret = clk_prepare_enable(dmadev->clk);
1304         if (ret < 0) {
1305                 dev_err(&pdev->dev, "clk_prep_enable error: %d\n", ret);
1306                 return ret;
1307         }
1308 
1309         dmadev->mem2mem = of_property_read_bool(pdev->dev.of_node,
1310                                                 "st,mem2mem");
1311 
1312         dmadev->rst = devm_reset_control_get(&pdev->dev, NULL);
1313         if (!IS_ERR(dmadev->rst)) {
1314                 reset_control_assert(dmadev->rst);
1315                 udelay(2);
1316                 reset_control_deassert(dmadev->rst);
1317         }
1318 
1319         dma_cap_set(DMA_SLAVE, dd->cap_mask);
1320         dma_cap_set(DMA_PRIVATE, dd->cap_mask);
1321         dma_cap_set(DMA_CYCLIC, dd->cap_mask);
1322         dd->device_alloc_chan_resources = stm32_dma_alloc_chan_resources;
1323         dd->device_free_chan_resources = stm32_dma_free_chan_resources;
1324         dd->device_tx_status = stm32_dma_tx_status;
1325         dd->device_issue_pending = stm32_dma_issue_pending;
1326         dd->device_prep_slave_sg = stm32_dma_prep_slave_sg;
1327         dd->device_prep_dma_cyclic = stm32_dma_prep_dma_cyclic;
1328         dd->device_config = stm32_dma_slave_config;
1329         dd->device_terminate_all = stm32_dma_terminate_all;
1330         dd->device_synchronize = stm32_dma_synchronize;
1331         dd->src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
1332                 BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
1333                 BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
1334         dd->dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
1335                 BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
1336                 BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
1337         dd->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
1338         dd->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
1339         dd->max_burst = STM32_DMA_MAX_BURST;
1340         dd->dev = &pdev->dev;
1341         INIT_LIST_HEAD(&dd->channels);
1342 
1343         if (dmadev->mem2mem) {
1344                 dma_cap_set(DMA_MEMCPY, dd->cap_mask);
1345                 dd->device_prep_dma_memcpy = stm32_dma_prep_dma_memcpy;
1346                 dd->directions |= BIT(DMA_MEM_TO_MEM);
1347         }
1348 
1349         for (i = 0; i < STM32_DMA_MAX_CHANNELS; i++) {
1350                 chan = &dmadev->chan[i];
1351                 chan->id = i;
1352                 chan->vchan.desc_free = stm32_dma_desc_free;
1353                 vchan_init(&chan->vchan, dd);
1354         }
1355 
1356         ret = dma_async_device_register(dd);
1357         if (ret)
1358                 goto clk_free;
1359 
1360         for (i = 0; i < STM32_DMA_MAX_CHANNELS; i++) {
1361                 chan = &dmadev->chan[i];
1362                 ret = platform_get_irq(pdev, i);
1363                 if (ret < 0)
1364                         goto err_unregister;
1365                 chan->irq = ret;
1366 
1367                 ret = devm_request_irq(&pdev->dev, chan->irq,
1368                                        stm32_dma_chan_irq, 0,
1369                                        dev_name(chan2dev(chan)), chan);
1370                 if (ret) {
1371                         dev_err(&pdev->dev,
1372                                 "request_irq failed with err %d channel %d\n",
1373                                 ret, i);
1374                         goto err_unregister;
1375                 }
1376         }
1377 
1378         ret = of_dma_controller_register(pdev->dev.of_node,
1379                                          stm32_dma_of_xlate, dmadev);
1380         if (ret < 0) {
1381                 dev_err(&pdev->dev,
1382                         "STM32 DMA DMA OF registration failed %d\n", ret);
1383                 goto err_unregister;
1384         }
1385 
1386         platform_set_drvdata(pdev, dmadev);
1387 
1388         pm_runtime_set_active(&pdev->dev);
1389         pm_runtime_enable(&pdev->dev);
1390         pm_runtime_get_noresume(&pdev->dev);
1391         pm_runtime_put(&pdev->dev);
1392 
1393         dev_info(&pdev->dev, "STM32 DMA driver registered\n");
1394 
1395         return 0;
1396 
1397 err_unregister:
1398         dma_async_device_unregister(dd);
1399 clk_free:
1400         clk_disable_unprepare(dmadev->clk);
1401 
1402         return ret;
1403 }
1404 
1405 #ifdef CONFIG_PM
1406 static int stm32_dma_runtime_suspend(struct device *dev)
1407 {
1408         struct stm32_dma_device *dmadev = dev_get_drvdata(dev);
1409 
1410         clk_disable_unprepare(dmadev->clk);
1411 
1412         return 0;
1413 }
1414 
1415 static int stm32_dma_runtime_resume(struct device *dev)
1416 {
1417         struct stm32_dma_device *dmadev = dev_get_drvdata(dev);
1418         int ret;
1419 
1420         ret = clk_prepare_enable(dmadev->clk);
1421         if (ret) {
1422                 dev_err(dev, "failed to prepare_enable clock\n");
1423                 return ret;
1424         }
1425 
1426         return 0;
1427 }
1428 #endif
1429 
1430 static const struct dev_pm_ops stm32_dma_pm_ops = {
1431         SET_RUNTIME_PM_OPS(stm32_dma_runtime_suspend,
1432                            stm32_dma_runtime_resume, NULL)
1433 };
1434 
1435 static struct platform_driver stm32_dma_driver = {
1436         .driver = {
1437                 .name = "stm32-dma",
1438                 .of_match_table = stm32_dma_of_match,
1439                 .pm = &stm32_dma_pm_ops,
1440         },
1441 };
1442 
1443 static int __init stm32_dma_init(void)
1444 {
1445         return platform_driver_probe(&stm32_dma_driver, stm32_dma_probe);
1446 }
1447 subsys_initcall(stm32_dma_init);
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/dma/stm32-dma.c

DEFINITIONS
