kernel/drivers/mmc/host/tmio_mmc_dma.c

   1 /*
   2  * linux/drivers/mmc/tmio_mmc_dma.c
   3  *
   4  * Copyright (C) 2010-2011 Guennadi Liakhovetski
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * DMA function for TMIO MMC implementations
  11  */
  12
  13 #include <linux/device.h>
  14 #include <linux/dma-mapping.h>
  15 #include <linux/dmaengine.h>
  16 #include <linux/mfd/tmio.h>
  17 #include <linux/mmc/host.h>
  18 #include <linux/mmc/tmio.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/scatterlist.h>
  21
  22 #include "tmio_mmc.h"
  23
  24 #define TMIO_MMC_MIN_DMA_LEN 8
  25
  26 void tmio_mmc_enable_dma(struct tmio_mmc_host *host, bool enable)
  27 {
  28         if (!host->chan_tx || !host->chan_rx)
  29                 return;
  30
  31         if (host->dma->enable)
  32                 host->dma->enable(host, enable);
  33 }
  34
  35 void tmio_mmc_abort_dma(struct tmio_mmc_host *host)
  36 {
  37         tmio_mmc_enable_dma(host, false);
  38
  39         if (host->chan_rx)
  40                 dmaengine_terminate_all(host->chan_rx);
  41         if (host->chan_tx)
  42                 dmaengine_terminate_all(host->chan_tx);
  43
  44         tmio_mmc_enable_dma(host, true);
  45 }
  46
  47 static void tmio_mmc_start_dma_rx(struct tmio_mmc_host *host)
  48 {
  49         struct scatterlist *sg = host->sg_ptr, *sg_tmp;
  50         struct dma_async_tx_descriptor *desc = NULL;
  51         struct dma_chan *chan = host->chan_rx;
  52         dma_cookie_t cookie;
  53         int ret, i;
  54         bool aligned = true, multiple = true;
  55         unsigned int align = (1 << host->pdata->alignment_shift) - 1;
  56
  57         for_each_sg(sg, sg_tmp, host->sg_len, i) {
  58                 if (sg_tmp->offset & align)
  59                         aligned = false;
  60                 if (sg_tmp->length & align) {
  61                         multiple = false;
  62                         break;
  63                 }
  64         }
  65
  66         if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_CACHE_SIZE ||
  67                           (align & PAGE_MASK))) || !multiple) {
  68                 ret = -EINVAL;
  69                 goto pio;
  70         }
  71
  72         if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
  73                 host->force_pio = true;
  74                 return;
  75         }
  76
  77         tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_RXRDY);
  78
  79         /* The only sg element can be unaligned, use our bounce buffer then */
  80         if (!aligned) {
  81                 sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
  82                 host->sg_ptr = &host->bounce_sg;
  83                 sg = host->sg_ptr;
  84         }
  85
  86         ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_FROM_DEVICE);
  87         if (ret > 0)
  88                 desc = dmaengine_prep_slave_sg(chan, sg, ret,
  89                         DMA_DEV_TO_MEM, DMA_CTRL_ACK);
  90
  91         if (desc) {
  92                 cookie = dmaengine_submit(desc);
  93                 if (cookie < 0) {
  94                         desc = NULL;
  95                         ret = cookie;
  96                 }
  97         }
  98         dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n",
  99                 __func__, host->sg_len, ret, cookie, host->mrq);
 100
 101 pio:
 102         if (!desc) {
 103                 /* DMA failed, fall back to PIO */
 104                 tmio_mmc_enable_dma(host, false);
 105                 if (ret >= 0)
 106                         ret = -EIO;
 107                 host->chan_rx = NULL;
 108                 dma_release_channel(chan);
 109                 /* Free the Tx channel too */
 110                 chan = host->chan_tx;
 111                 if (chan) {
 112                         host->chan_tx = NULL;
 113                         dma_release_channel(chan);
 114                 }
 115                 dev_warn(&host->pdev->dev,
 116                          "DMA failed: %d, falling back to PIO\n", ret);
 117         }
 118
 119         dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d, sg[%d]\n", __func__,
 120                 desc, cookie, host->sg_len);
 121 }
 122
 123 static void tmio_mmc_start_dma_tx(struct tmio_mmc_host *host)
 124 {
 125         struct scatterlist *sg = host->sg_ptr, *sg_tmp;
 126         struct dma_async_tx_descriptor *desc = NULL;
 127         struct dma_chan *chan = host->chan_tx;
 128         dma_cookie_t cookie;
 129         int ret, i;
 130         bool aligned = true, multiple = true;
 131         unsigned int align = (1 << host->pdata->alignment_shift) - 1;
 132
 133         for_each_sg(sg, sg_tmp, host->sg_len, i) {
 134                 if (sg_tmp->offset & align)
 135                         aligned = false;
 136                 if (sg_tmp->length & align) {
 137                         multiple = false;
 138                         break;
 139                 }
 140         }
 141
 142         if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_CACHE_SIZE ||
 143                           (align & PAGE_MASK))) || !multiple) {
 144                 ret = -EINVAL;
 145                 goto pio;
 146         }
 147
 148         if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
 149                 host->force_pio = true;
 150                 return;
 151         }
 152
 153         tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_TXRQ);
 154
 155         /* The only sg element can be unaligned, use our bounce buffer then */
 156         if (!aligned) {
 157                 unsigned long flags;
 158                 void *sg_vaddr = tmio_mmc_kmap_atomic(sg, &flags);
 159                 sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
 160                 memcpy(host->bounce_buf, sg_vaddr, host->bounce_sg.length);
 161                 tmio_mmc_kunmap_atomic(sg, &flags, sg_vaddr);
 162                 host->sg_ptr = &host->bounce_sg;
 163                 sg = host->sg_ptr;
 164         }
 165
 166         ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_TO_DEVICE);
 167         if (ret > 0)
 168                 desc = dmaengine_prep_slave_sg(chan, sg, ret,
 169                         DMA_MEM_TO_DEV, DMA_CTRL_ACK);
 170
 171         if (desc) {
 172                 cookie = dmaengine_submit(desc);
 173                 if (cookie < 0) {
 174                         desc = NULL;
 175                         ret = cookie;
 176                 }
 177         }
 178         dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n",
 179                 __func__, host->sg_len, ret, cookie, host->mrq);
 180
 181 pio:
 182         if (!desc) {
 183                 /* DMA failed, fall back to PIO */
 184                 tmio_mmc_enable_dma(host, false);
 185                 if (ret >= 0)
 186                         ret = -EIO;
 187                 host->chan_tx = NULL;
 188                 dma_release_channel(chan);
 189                 /* Free the Rx channel too */
 190                 chan = host->chan_rx;
 191                 if (chan) {
 192                         host->chan_rx = NULL;
 193                         dma_release_channel(chan);
 194                 }
 195                 dev_warn(&host->pdev->dev,
 196                          "DMA failed: %d, falling back to PIO\n", ret);
 197         }
 198
 199         dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d\n", __func__,
 200                 desc, cookie);
 201 }
 202
 203 void tmio_mmc_start_dma(struct tmio_mmc_host *host,
 204                                struct mmc_data *data)
 205 {
 206         if (data->flags & MMC_DATA_READ) {
 207                 if (host->chan_rx)
 208                         tmio_mmc_start_dma_rx(host);
 209         } else {
 210                 if (host->chan_tx)
 211                         tmio_mmc_start_dma_tx(host);
 212         }
 213 }
 214
 215 static void tmio_mmc_issue_tasklet_fn(unsigned long priv)
 216 {
 217         struct tmio_mmc_host *host = (struct tmio_mmc_host *)priv;
 218         struct dma_chan *chan = NULL;
 219
 220         spin_lock_irq(&host->lock);
 221
 222         if (host && host->data) {
 223                 if (host->data->flags & MMC_DATA_READ)
 224                         chan = host->chan_rx;
 225                 else
 226                         chan = host->chan_tx;
 227         }
 228
 229         spin_unlock_irq(&host->lock);
 230
 231         tmio_mmc_enable_mmc_irqs(host, TMIO_STAT_DATAEND);
 232
 233         if (chan)
 234                 dma_async_issue_pending(chan);
 235 }
 236
 237 static void tmio_mmc_tasklet_fn(unsigned long arg)
 238 {
 239         struct tmio_mmc_host *host = (struct tmio_mmc_host *)arg;
 240
 241         spin_lock_irq(&host->lock);
 242
 243         if (!host->data)
 244                 goto out;
 245
 246         if (host->data->flags & MMC_DATA_READ)
 247                 dma_unmap_sg(host->chan_rx->device->dev,
 248                              host->sg_ptr, host->sg_len,
 249                              DMA_FROM_DEVICE);
 250         else
 251                 dma_unmap_sg(host->chan_tx->device->dev,
 252                              host->sg_ptr, host->sg_len,
 253                              DMA_TO_DEVICE);
 254
 255         tmio_mmc_do_data_irq(host);
 256 out:
 257         spin_unlock_irq(&host->lock);
 258 }
 259
 260 void tmio_mmc_request_dma(struct tmio_mmc_host *host, struct tmio_mmc_data *pdata)
 261 {
 262         /* We can only either use DMA for both Tx and Rx or not use it at all */
 263         if (!host->dma || (!host->pdev->dev.of_node &&
 264                 (!pdata->chan_priv_tx || !pdata->chan_priv_rx)))
 265                 return;
 266
 267         if (!host->chan_tx && !host->chan_rx) {
 268                 struct resource *res = platform_get_resource(host->pdev,
 269                                                              IORESOURCE_MEM, 0);
 270                 struct dma_slave_config cfg = {};
 271                 dma_cap_mask_t mask;
 272                 int ret;
 273
 274                 if (!res)
 275                         return;
 276
 277                 dma_cap_zero(mask);
 278                 dma_cap_set(DMA_SLAVE, mask);
 279
 280                 host->chan_tx = dma_request_slave_channel_compat(mask,
 281                                         host->dma->filter, pdata->chan_priv_tx,
 282                                         &host->pdev->dev, "tx");
 283                 dev_dbg(&host->pdev->dev, "%s: TX: got channel %p\n", __func__,
 284                         host->chan_tx);
 285
 286                 if (!host->chan_tx)
 287                         return;
 288
 289                 cfg.direction = DMA_MEM_TO_DEV;
 290                 cfg.dst_addr = res->start + (CTL_SD_DATA_PORT << host->bus_shift);
 291                 cfg.dst_addr_width = host->dma->dma_buswidth;
 292                 if (!cfg.dst_addr_width)
 293                         cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 294                 cfg.src_addr = 0;
 295                 ret = dmaengine_slave_config(host->chan_tx, &cfg);
 296                 if (ret < 0)
 297                         goto ecfgtx;
 298
 299                 host->chan_rx = dma_request_slave_channel_compat(mask,
 300                                         host->dma->filter, pdata->chan_priv_rx,
 301                                         &host->pdev->dev, "rx");
 302                 dev_dbg(&host->pdev->dev, "%s: RX: got channel %p\n", __func__,
 303                         host->chan_rx);
 304
 305                 if (!host->chan_rx)
 306                         goto ereqrx;
 307
 308                 cfg.direction = DMA_DEV_TO_MEM;
 309                 cfg.src_addr = cfg.dst_addr + host->pdata->dma_rx_offset;
 310                 cfg.src_addr_width = host->dma->dma_buswidth;
 311                 if (!cfg.src_addr_width)
 312                         cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 313                 cfg.dst_addr = 0;
 314                 ret = dmaengine_slave_config(host->chan_rx, &cfg);
 315                 if (ret < 0)
 316                         goto ecfgrx;
 317
 318                 host->bounce_buf = (u8 *)__get_free_page(GFP_KERNEL | GFP_DMA);
 319                 if (!host->bounce_buf)
 320                         goto ebouncebuf;
 321
 322                 tasklet_init(&host->dma_complete, tmio_mmc_tasklet_fn, (unsigned long)host);
 323                 tasklet_init(&host->dma_issue, tmio_mmc_issue_tasklet_fn, (unsigned long)host);
 324         }
 325
 326         tmio_mmc_enable_dma(host, true);
 327
 328         return;
 329
 330 ebouncebuf:
 331 ecfgrx:
 332         dma_release_channel(host->chan_rx);
 333         host->chan_rx = NULL;
 334 ereqrx:
 335 ecfgtx:
 336         dma_release_channel(host->chan_tx);
 337         host->chan_tx = NULL;
 338 }
 339
 340 void tmio_mmc_release_dma(struct tmio_mmc_host *host)
 341 {
 342         if (host->chan_tx) {
 343                 struct dma_chan *chan = host->chan_tx;
 344                 host->chan_tx = NULL;
 345                 dma_release_channel(chan);
 346         }
 347         if (host->chan_rx) {
 348                 struct dma_chan *chan = host->chan_rx;
 349                 host->chan_rx = NULL;
 350                 dma_release_channel(chan);
 351         }
 352         if (host->bounce_buf) {
 353                 free_pages((unsigned long)host->bounce_buf, 0);
 354                 host->bounce_buf = NULL;
 355         }
 356 }