sound/soc/sh/rcar/dma.c

   1 /*
   2  * Renesas R-Car Audio DMAC support
   3  *
   4  * Copyright (C) 2015 Renesas Electronics Corp.
   5  * Copyright (c) 2015 Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11 #include <linux/delay.h>
  12 #include <linux/of_dma.h>
  13 #include "rsnd.h"
  14
  15 /*
  16  * Audio DMAC peri peri register
  17  */
  18 #define PDMASAR         0x00
  19 #define PDMADAR         0x04
  20 #define PDMACHCR        0x0c
  21
  22 /* PDMACHCR */
  23 #define PDMACHCR_DE             (1 << 0)
  24
  25 struct rsnd_dma_ctrl {
  26         void __iomem *base;
  27         int dmapp_num;
  28 };
  29
  30 #define rsnd_priv_to_dmac(p)    ((struct rsnd_dma_ctrl *)(p)->dma)
  31
  32 /*
  33  *              Audio DMAC
  34  */
  35 static void __rsnd_dmaen_complete(struct rsnd_mod *mod,
  36                                   struct rsnd_dai_stream *io)
  37 {
  38         struct rsnd_priv *priv = rsnd_mod_to_priv(mod);
  39         bool elapsed = false;
  40         unsigned long flags;
  41
  42         /*
  43          * Renesas sound Gen1 needs 1 DMAC,
  44          * Gen2 needs 2 DMAC.
  45          * In Gen2 case, it are Audio-DMAC, and Audio-DMAC-peri-peri.
  46          * But, Audio-DMAC-peri-peri doesn't have interrupt,
  47          * and this driver is assuming that here.
  48          *
  49          * If Audio-DMAC-peri-peri has interrpt,
  50          * rsnd_dai_pointer_update() will be called twice,
  51          * ant it will breaks io->byte_pos
  52          */
  53         spin_lock_irqsave(&priv->lock, flags);
  54
  55         if (rsnd_io_is_working(io))
  56                 elapsed = rsnd_dai_pointer_update(io, io->byte_per_period);
  57
  58         spin_unlock_irqrestore(&priv->lock, flags);
  59
  60         if (elapsed)
  61                 rsnd_dai_period_elapsed(io);
  62 }
  63
  64 static void rsnd_dmaen_complete(void *data)
  65 {
  66         struct rsnd_mod *mod = data;
  67
  68         rsnd_mod_interrupt(mod, __rsnd_dmaen_complete);
  69 }
  70
  71 static void rsnd_dmaen_stop(struct rsnd_dai_stream *io, struct rsnd_dma *dma)
  72 {
  73         struct rsnd_dmaen *dmaen = rsnd_dma_to_dmaen(dma);
  74
  75         dmaengine_terminate_all(dmaen->chan);
  76 }
  77
  78 static void rsnd_dmaen_start(struct rsnd_dai_stream *io, struct rsnd_dma *dma)
  79 {
  80         struct rsnd_dmaen *dmaen = rsnd_dma_to_dmaen(dma);
  81         struct rsnd_mod *mod = rsnd_dma_to_mod(dma);
  82         struct rsnd_priv *priv = rsnd_mod_to_priv(mod);
  83         struct snd_pcm_substream *substream = io->substream;
  84         struct device *dev = rsnd_priv_to_dev(priv);
  85         struct dma_async_tx_descriptor *desc;
  86         int is_play = rsnd_io_is_play(io);
  87
  88         desc = dmaengine_prep_dma_cyclic(dmaen->chan,
  89                                          substream->runtime->dma_addr,
  90                                          snd_pcm_lib_buffer_bytes(substream),
  91                                          snd_pcm_lib_period_bytes(substream),
  92                                          is_play ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM,
  93                                          DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
  94
  95         if (!desc) {
  96                 dev_err(dev, "dmaengine_prep_slave_sg() fail\n");
  97                 return;
  98         }
  99
 100         desc->callback          = rsnd_dmaen_complete;
 101         desc->callback_param    = mod;
 102
 103         if (dmaengine_submit(desc) < 0) {
 104                 dev_err(dev, "dmaengine_submit() fail\n");
 105                 return;
 106         }
 107
 108         dma_async_issue_pending(dmaen->chan);
 109 }
 110
 111 struct dma_chan *rsnd_dma_request_channel(struct device_node *of_node,
 112                                           struct rsnd_mod *mod, char *name)
 113 {
 114         struct dma_chan *chan;
 115         struct device_node *np;
 116         int i = 0;
 117
 118         for_each_child_of_node(of_node, np) {
 119                 if (i == rsnd_mod_id(mod))
 120                         break;
 121                 i++;
 122         }
 123
 124         chan = of_dma_request_slave_channel(np, name);
 125
 126         of_node_put(np);
 127         of_node_put(of_node);
 128
 129         return chan;
 130 }
 131
 132 static struct dma_chan *rsnd_dmaen_request_channel(struct rsnd_dai_stream *io,
 133                                                    struct rsnd_mod *mod_from,
 134                                                    struct rsnd_mod *mod_to)
 135 {
 136         if ((!mod_from && !mod_to) ||
 137             (mod_from && mod_to))
 138                 return NULL;
 139
 140         if (mod_from)
 141                 return rsnd_mod_dma_req(io, mod_from);
 142         else
 143                 return rsnd_mod_dma_req(io, mod_to);
 144 }
 145
 146 static int rsnd_dmaen_init(struct rsnd_dai_stream *io,
 147                            struct rsnd_dma *dma, int id,
 148                            struct rsnd_mod *mod_from, struct rsnd_mod *mod_to)
 149 {
 150         struct rsnd_dmaen *dmaen = rsnd_dma_to_dmaen(dma);
 151         struct rsnd_priv *priv = rsnd_io_to_priv(io);
 152         struct device *dev = rsnd_priv_to_dev(priv);
 153         struct dma_slave_config cfg = {};
 154         int is_play = rsnd_io_is_play(io);
 155         int ret;
 156
 157         if (dmaen->chan) {
 158                 dev_err(dev, "it already has dma channel\n");
 159                 return -EIO;
 160         }
 161
 162         if (dev->of_node) {
 163                 dmaen->chan = rsnd_dmaen_request_channel(io, mod_from, mod_to);
 164         } else {
 165                 dma_cap_mask_t mask;
 166
 167                 dma_cap_zero(mask);
 168                 dma_cap_set(DMA_SLAVE, mask);
 169
 170                 dmaen->chan = dma_request_channel(mask, shdma_chan_filter,
 171                                                   (void *)id);
 172         }
 173         if (IS_ERR_OR_NULL(dmaen->chan)) {
 174                 dmaen->chan = NULL;
 175                 dev_err(dev, "can't get dma channel\n");
 176                 goto rsnd_dma_channel_err;
 177         }
 178
 179         cfg.direction   = is_play ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM;
 180         cfg.src_addr    = dma->src_addr;
 181         cfg.dst_addr    = dma->dst_addr;
 182         cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
 183         cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
 184
 185         dev_dbg(dev, "dma : %pad -> %pad\n",
 186                 &cfg.src_addr, &cfg.dst_addr);
 187
 188         ret = dmaengine_slave_config(dmaen->chan, &cfg);
 189         if (ret < 0)
 190                 goto rsnd_dma_init_err;
 191
 192         return 0;
 193
 194 rsnd_dma_init_err:
 195         rsnd_dma_quit(io, dma);
 196 rsnd_dma_channel_err:
 197
 198         /*
 199          * DMA failed. try to PIO mode
 200          * see
 201          *      rsnd_ssi_fallback()
 202          *      rsnd_rdai_continuance_probe()
 203          */
 204         return -EAGAIN;
 205 }
 206
 207 static void rsnd_dmaen_quit(struct rsnd_dai_stream *io, struct rsnd_dma *dma)
 208 {
 209         struct rsnd_dmaen *dmaen = rsnd_dma_to_dmaen(dma);
 210
 211         if (dmaen->chan)
 212                 dma_release_channel(dmaen->chan);
 213
 214         dmaen->chan = NULL;
 215 }
 216
 217 static struct rsnd_dma_ops rsnd_dmaen_ops = {
 218         .start  = rsnd_dmaen_start,
 219         .stop   = rsnd_dmaen_stop,
 220         .init   = rsnd_dmaen_init,
 221         .quit   = rsnd_dmaen_quit,
 222 };
 223
 224 /*
 225  *              Audio DMAC peri peri
 226  */
 227 static const u8 gen2_id_table_ssiu[] = {
 228         0x00, /* SSI00 */
 229         0x04, /* SSI10 */
 230         0x08, /* SSI20 */
 231         0x0c, /* SSI3  */
 232         0x0d, /* SSI4  */
 233         0x0e, /* SSI5  */
 234         0x0f, /* SSI6  */
 235         0x10, /* SSI7  */
 236         0x11, /* SSI8  */
 237         0x12, /* SSI90 */
 238 };
 239 static const u8 gen2_id_table_scu[] = {
 240         0x2d, /* SCU_SRCI0 */
 241         0x2e, /* SCU_SRCI1 */
 242         0x2f, /* SCU_SRCI2 */
 243         0x30, /* SCU_SRCI3 */
 244         0x31, /* SCU_SRCI4 */
 245         0x32, /* SCU_SRCI5 */
 246         0x33, /* SCU_SRCI6 */
 247         0x34, /* SCU_SRCI7 */
 248         0x35, /* SCU_SRCI8 */
 249         0x36, /* SCU_SRCI9 */
 250 };
 251 static const u8 gen2_id_table_cmd[] = {
 252         0x37, /* SCU_CMD0 */
 253         0x38, /* SCU_CMD1 */
 254 };
 255
 256 static u32 rsnd_dmapp_get_id(struct rsnd_dai_stream *io,
 257                              struct rsnd_mod *mod)
 258 {
 259         struct rsnd_mod *ssi = rsnd_io_to_mod_ssi(io);
 260         struct rsnd_mod *src = rsnd_io_to_mod_src(io);
 261         struct rsnd_mod *dvc = rsnd_io_to_mod_dvc(io);
 262         const u8 *entry = NULL;
 263         int id = rsnd_mod_id(mod);
 264         int size = 0;
 265
 266         if (mod == ssi) {
 267                 entry = gen2_id_table_ssiu;
 268                 size = ARRAY_SIZE(gen2_id_table_ssiu);
 269         } else if (mod == src) {
 270                 entry = gen2_id_table_scu;
 271                 size = ARRAY_SIZE(gen2_id_table_scu);
 272         } else if (mod == dvc) {
 273                 entry = gen2_id_table_cmd;
 274                 size = ARRAY_SIZE(gen2_id_table_cmd);
 275         }
 276
 277         if (!entry)
 278                 return 0xFF;
 279
 280         if (size <= id)
 281                 return 0xFF;
 282
 283         return entry[id];
 284 }
 285
 286 static u32 rsnd_dmapp_get_chcr(struct rsnd_dai_stream *io,
 287                                struct rsnd_mod *mod_from,
 288                                struct rsnd_mod *mod_to)
 289 {
 290         return  (rsnd_dmapp_get_id(io, mod_from) << 24) +
 291                 (rsnd_dmapp_get_id(io, mod_to) << 16);
 292 }
 293
 294 #define rsnd_dmapp_addr(dmac, dma, reg) \
 295         (dmac->base + 0x20 + reg + \
 296          (0x10 * rsnd_dma_to_dmapp(dma)->dmapp_id))
 297 static void rsnd_dmapp_write(struct rsnd_dma *dma, u32 data, u32 reg)
 298 {
 299         struct rsnd_mod *mod = rsnd_dma_to_mod(dma);
 300         struct rsnd_priv *priv = rsnd_mod_to_priv(mod);
 301         struct rsnd_dma_ctrl *dmac = rsnd_priv_to_dmac(priv);
 302         struct device *dev = rsnd_priv_to_dev(priv);
 303
 304         dev_dbg(dev, "w %p : %08x\n", rsnd_dmapp_addr(dmac, dma, reg), data);
 305
 306         iowrite32(data, rsnd_dmapp_addr(dmac, dma, reg));
 307 }
 308
 309 static u32 rsnd_dmapp_read(struct rsnd_dma *dma, u32 reg)
 310 {
 311         struct rsnd_mod *mod = rsnd_dma_to_mod(dma);
 312         struct rsnd_priv *priv = rsnd_mod_to_priv(mod);
 313         struct rsnd_dma_ctrl *dmac = rsnd_priv_to_dmac(priv);
 314
 315         return ioread32(rsnd_dmapp_addr(dmac, dma, reg));
 316 }
 317
 318 static void rsnd_dmapp_stop(struct rsnd_dai_stream *io, struct rsnd_dma *dma)
 319 {
 320         int i;
 321
 322         rsnd_dmapp_write(dma, 0, PDMACHCR);
 323
 324         for (i = 0; i < 1024; i++) {
 325                 if (0 == rsnd_dmapp_read(dma, PDMACHCR))
 326                         return;
 327                 udelay(1);
 328         }
 329 }
 330
 331 static void rsnd_dmapp_start(struct rsnd_dai_stream *io, struct rsnd_dma *dma)
 332 {
 333         struct rsnd_dmapp *dmapp = rsnd_dma_to_dmapp(dma);
 334
 335         rsnd_dmapp_write(dma, dma->src_addr,    PDMASAR);
 336         rsnd_dmapp_write(dma, dma->dst_addr,    PDMADAR);
 337         rsnd_dmapp_write(dma, dmapp->chcr,      PDMACHCR);
 338 }
 339
 340 static int rsnd_dmapp_init(struct rsnd_dai_stream *io,
 341                            struct rsnd_dma *dma, int id,
 342                            struct rsnd_mod *mod_from, struct rsnd_mod *mod_to)
 343 {
 344         struct rsnd_dmapp *dmapp = rsnd_dma_to_dmapp(dma);
 345         struct rsnd_priv *priv = rsnd_io_to_priv(io);
 346         struct rsnd_dma_ctrl *dmac = rsnd_priv_to_dmac(priv);
 347         struct device *dev = rsnd_priv_to_dev(priv);
 348
 349         dmapp->dmapp_id = dmac->dmapp_num;
 350         dmapp->chcr = rsnd_dmapp_get_chcr(io, mod_from, mod_to) | PDMACHCR_DE;
 351
 352         dmac->dmapp_num++;
 353
 354         rsnd_dmapp_stop(io, dma);
 355
 356         dev_dbg(dev, "id/src/dst/chcr = %d/%pad/%pad/%08x\n",
 357                 dmapp->dmapp_id, &dma->src_addr, &dma->dst_addr, dmapp->chcr);
 358
 359         return 0;
 360 }
 361
 362 static struct rsnd_dma_ops rsnd_dmapp_ops = {
 363         .start  = rsnd_dmapp_start,
 364         .stop   = rsnd_dmapp_stop,
 365         .init   = rsnd_dmapp_init,
 366         .quit   = rsnd_dmapp_stop,
 367 };
 368
 369 /*
 370  *              Common DMAC Interface
 371  */
 372
 373 /*
 374  *      DMA read/write register offset
 375  *
 376  *      RSND_xxx_I_N    for Audio DMAC input
 377  *      RSND_xxx_O_N    for Audio DMAC output
 378  *      RSND_xxx_I_P    for Audio DMAC peri peri input
 379  *      RSND_xxx_O_P    for Audio DMAC peri peri output
 380  *
 381  *      ex) R-Car H2 case
 382  *            mod        / DMAC in    / DMAC out   / DMAC PP in / DMAC pp out
 383  *      SSI : 0xec541000 / 0xec241008 / 0xec24100c
 384  *      SSIU: 0xec541000 / 0xec100000 / 0xec100000 / 0xec400000 / 0xec400000
 385  *      SCU : 0xec500000 / 0xec000000 / 0xec004000 / 0xec300000 / 0xec304000
 386  *      CMD : 0xec500000 /            / 0xec008000                0xec308000
 387  */
 388 #define RDMA_SSI_I_N(addr, i)   (addr ##_reg - 0x00300000 + (0x40 * i) + 0x8)
 389 #define RDMA_SSI_O_N(addr, i)   (addr ##_reg - 0x00300000 + (0x40 * i) + 0xc)
 390
 391 #define RDMA_SSIU_I_N(addr, i)  (addr ##_reg - 0x00441000 + (0x1000 * i))
 392 #define RDMA_SSIU_O_N(addr, i)  (addr ##_reg - 0x00441000 + (0x1000 * i))
 393
 394 #define RDMA_SSIU_I_P(addr, i)  (addr ##_reg - 0x00141000 + (0x1000 * i))
 395 #define RDMA_SSIU_O_P(addr, i)  (addr ##_reg - 0x00141000 + (0x1000 * i))
 396
 397 #define RDMA_SRC_I_N(addr, i)   (addr ##_reg - 0x00500000 + (0x400 * i))
 398 #define RDMA_SRC_O_N(addr, i)   (addr ##_reg - 0x004fc000 + (0x400 * i))
 399
 400 #define RDMA_SRC_I_P(addr, i)   (addr ##_reg - 0x00200000 + (0x400 * i))
 401 #define RDMA_SRC_O_P(addr, i)   (addr ##_reg - 0x001fc000 + (0x400 * i))
 402
 403 #define RDMA_CMD_O_N(addr, i)   (addr ##_reg - 0x004f8000 + (0x400 * i))
 404 #define RDMA_CMD_O_P(addr, i)   (addr ##_reg - 0x001f8000 + (0x400 * i))
 405
 406 static dma_addr_t
 407 rsnd_gen2_dma_addr(struct rsnd_dai_stream *io,
 408                    struct rsnd_mod *mod,
 409                    int is_play, int is_from)
 410 {
 411         struct rsnd_priv *priv = rsnd_io_to_priv(io);
 412         struct device *dev = rsnd_priv_to_dev(priv);
 413         phys_addr_t ssi_reg = rsnd_gen_get_phy_addr(priv, RSND_GEN2_SSI);
 414         phys_addr_t src_reg = rsnd_gen_get_phy_addr(priv, RSND_GEN2_SCU);
 415         int is_ssi = !!(rsnd_io_to_mod_ssi(io) == mod);
 416         int use_src = !!rsnd_io_to_mod_src(io);
 417         int use_dvc = !!rsnd_io_to_mod_dvc(io);
 418         int id = rsnd_mod_id(mod);
 419         struct dma_addr {
 420                 dma_addr_t out_addr;
 421                 dma_addr_t in_addr;
 422         } dma_addrs[3][2][3] = {
 423                 /* SRC */
 424                 {{{ 0,                          0 },
 425                   /* Capture */
 426                   { RDMA_SRC_O_N(src, id),      RDMA_SRC_I_P(src, id) },
 427                   { RDMA_CMD_O_N(src, id),      RDMA_SRC_I_P(src, id) } },
 428                  /* Playback */
 429                  {{ 0,                          0, },
 430                   { RDMA_SRC_O_P(src, id),      RDMA_SRC_I_N(src, id) },
 431                   { RDMA_CMD_O_P(src, id),      RDMA_SRC_I_N(src, id) } }
 432                 },
 433                 /* SSI */
 434                 /* Capture */
 435                 {{{ RDMA_SSI_O_N(ssi, id),      0 },
 436                   { RDMA_SSIU_O_P(ssi, id),     0 },
 437                   { RDMA_SSIU_O_P(ssi, id),     0 } },
 438                  /* Playback */
 439                  {{ 0,                          RDMA_SSI_I_N(ssi, id) },
 440                   { 0,                          RDMA_SSIU_I_P(ssi, id) },
 441                   { 0,                          RDMA_SSIU_I_P(ssi, id) } }
 442                 },
 443                 /* SSIU */
 444                 /* Capture */
 445                 {{{ RDMA_SSIU_O_N(ssi, id),     0 },
 446                   { RDMA_SSIU_O_P(ssi, id),     0 },
 447                   { RDMA_SSIU_O_P(ssi, id),     0 } },
 448                  /* Playback */
 449                  {{ 0,                          RDMA_SSIU_I_N(ssi, id) },
 450                   { 0,                          RDMA_SSIU_I_P(ssi, id) },
 451                   { 0,                          RDMA_SSIU_I_P(ssi, id) } } },
 452         };
 453
 454         /* it shouldn't happen */
 455         if (use_dvc && !use_src)
 456                 dev_err(dev, "DVC is selected without SRC\n");
 457
 458         /* use SSIU or SSI ? */
 459         if (is_ssi && rsnd_ssi_use_busif(io, mod))
 460                 is_ssi++;
 461
 462         return (is_from) ?
 463                 dma_addrs[is_ssi][is_play][use_src + use_dvc].out_addr :
 464                 dma_addrs[is_ssi][is_play][use_src + use_dvc].in_addr;
 465 }
 466
 467 static dma_addr_t rsnd_dma_addr(struct rsnd_dai_stream *io,
 468                                 struct rsnd_mod *mod,
 469                                 int is_play, int is_from)
 470 {
 471         struct rsnd_priv *priv = rsnd_io_to_priv(io);
 472
 473         /*
 474          * gen1 uses default DMA addr
 475          */
 476         if (rsnd_is_gen1(priv))
 477                 return 0;
 478
 479         if (!mod)
 480                 return 0;
 481
 482         return rsnd_gen2_dma_addr(io, mod, is_play, is_from);
 483 }
 484
 485 #define MOD_MAX 4 /* MEM/SSI/SRC/DVC */
 486 static void rsnd_dma_of_path(struct rsnd_dma *dma,
 487                              struct rsnd_dai_stream *io,
 488                              int is_play,
 489                              struct rsnd_mod **mod_from,
 490                              struct rsnd_mod **mod_to)
 491 {
 492         struct rsnd_mod *this = rsnd_dma_to_mod(dma);
 493         struct rsnd_mod *ssi = rsnd_io_to_mod_ssi(io);
 494         struct rsnd_mod *src = rsnd_io_to_mod_src(io);
 495         struct rsnd_mod *dvc = rsnd_io_to_mod_dvc(io);
 496         struct rsnd_mod *mod[MOD_MAX];
 497         int i, index;
 498
 499
 500         for (i = 0; i < MOD_MAX; i++)
 501                 mod[i] = NULL;
 502
 503         /*
 504          * in play case...
 505          *
 506          * src -> dst
 507          *
 508          * mem -> SSI
 509          * mem -> SRC -> SSI
 510          * mem -> SRC -> DVC -> SSI
 511          */
 512         mod[0] = NULL; /* for "mem" */
 513         index = 1;
 514         for (i = 1; i < MOD_MAX; i++) {
 515                 if (!src) {
 516                         mod[i] = ssi;
 517                 } else if (!dvc) {
 518                         mod[i] = src;
 519                         src = NULL;
 520                 } else {
 521                         if ((!is_play) && (this == src))
 522                                 this = dvc;
 523
 524                         mod[i] = (is_play) ? src : dvc;
 525                         i++;
 526                         mod[i] = (is_play) ? dvc : src;
 527                         src = NULL;
 528                         dvc = NULL;
 529                 }
 530
 531                 if (mod[i] == this)
 532                         index = i;
 533
 534                 if (mod[i] == ssi)
 535                         break;
 536         }
 537
 538         if (is_play) {
 539                 *mod_from = mod[index - 1];
 540                 *mod_to   = mod[index];
 541         } else {
 542                 *mod_from = mod[index];
 543                 *mod_to   = mod[index - 1];
 544         }
 545 }
 546
 547 void rsnd_dma_stop(struct rsnd_dai_stream *io, struct rsnd_dma *dma)
 548 {
 549         dma->ops->stop(io, dma);
 550 }
 551
 552 void rsnd_dma_start(struct rsnd_dai_stream *io, struct rsnd_dma *dma)
 553 {
 554         dma->ops->start(io, dma);
 555 }
 556
 557 void rsnd_dma_quit(struct rsnd_dai_stream *io, struct rsnd_dma *dma)
 558 {
 559         struct rsnd_mod *mod = rsnd_dma_to_mod(dma);
 560         struct rsnd_priv *priv = rsnd_mod_to_priv(mod);
 561         struct rsnd_dma_ctrl *dmac = rsnd_priv_to_dmac(priv);
 562
 563         if (!dmac)
 564                 return;
 565
 566         dma->ops->quit(io, dma);
 567 }
 568
 569 int rsnd_dma_init(struct rsnd_dai_stream *io, struct rsnd_dma *dma, int id)
 570 {
 571         struct rsnd_mod *mod_from;
 572         struct rsnd_mod *mod_to;
 573         struct rsnd_priv *priv = rsnd_io_to_priv(io);
 574         struct rsnd_dma_ctrl *dmac = rsnd_priv_to_dmac(priv);
 575         int is_play = rsnd_io_is_play(io);
 576
 577         /*
 578          * DMA failed. try to PIO mode
 579          * see
 580          *      rsnd_ssi_fallback()
 581          *      rsnd_rdai_continuance_probe()
 582          */
 583         if (!dmac)
 584                 return -EAGAIN;
 585
 586         rsnd_dma_of_path(dma, io, is_play, &mod_from, &mod_to);
 587
 588         dma->src_addr = rsnd_dma_addr(io, mod_from, is_play, 1);
 589         dma->dst_addr = rsnd_dma_addr(io, mod_to,   is_play, 0);
 590
 591         /* for Gen2 */
 592         if (mod_from && mod_to)
 593                 dma->ops = &rsnd_dmapp_ops;
 594         else
 595                 dma->ops = &rsnd_dmaen_ops;
 596
 597         /* for Gen1, overwrite */
 598         if (rsnd_is_gen1(priv))
 599                 dma->ops = &rsnd_dmaen_ops;
 600
 601         return dma->ops->init(io, dma, id, mod_from, mod_to);
 602 }
 603
 604 int rsnd_dma_probe(struct platform_device *pdev,
 605                    const struct rsnd_of_data *of_data,
 606                    struct rsnd_priv *priv)
 607 {
 608         struct device *dev = rsnd_priv_to_dev(priv);
 609         struct rsnd_dma_ctrl *dmac;
 610         struct resource *res;
 611
 612         /*
 613          * for Gen1
 614          */
 615         if (rsnd_is_gen1(priv))
 616                 return 0;
 617
 618         /*
 619          * for Gen2
 620          */
 621         res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "audmapp");
 622         dmac = devm_kzalloc(dev, sizeof(*dmac), GFP_KERNEL);
 623         if (!dmac || !res) {
 624                 dev_err(dev, "dma allocate failed\n");
 625                 return 0; /* it will be PIO mode */
 626         }
 627
 628         dmac->dmapp_num = 0;
 629         dmac->base = devm_ioremap_resource(dev, res);
 630         if (IS_ERR(dmac->base))
 631                 return PTR_ERR(dmac->base);
 632
 633         priv->dma = dmac;
 634
 635         return 0;
 636 }