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 defined(CONFIG_SUPERH) || defined(CONFIG_ARCH_SHMOBILE)
  32         /* Switch DMA mode on or off - SuperH specific? */
  33         sd_ctrl_write16(host, CTL_DMA_ENABLE, enable ? 2 : 0);
  34 #endif
  35 }
  36
  37 static void tmio_mmc_start_dma_rx(struct tmio_mmc_host *host)
  38 {
  39         struct scatterlist *sg = host->sg_ptr, *sg_tmp;
  40         struct dma_async_tx_descriptor *desc = NULL;
  41         struct dma_chan *chan = host->chan_rx;
  42         struct tmio_mmc_data *pdata = host->pdata;
  43         dma_cookie_t cookie;
  44         int ret, i;
  45         bool aligned = true, multiple = true;
  46         unsigned int align = (1 << pdata->dma->alignment_shift) - 1;
  47
  48         for_each_sg(sg, sg_tmp, host->sg_len, i) {
  49                 if (sg_tmp->offset & align)
  50                         aligned = false;
  51                 if (sg_tmp->length & align) {
  52                         multiple = false;
  53                         break;
  54                 }
  55         }
  56
  57         if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_CACHE_SIZE ||
  58                           (align & PAGE_MASK))) || !multiple) {
  59                 ret = -EINVAL;
  60                 goto pio;
  61         }
  62
  63         if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
  64                 host->force_pio = true;
  65                 return;
  66         }
  67
  68         tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_RXRDY);
  69
  70         /* The only sg element can be unaligned, use our bounce buffer then */
  71         if (!aligned) {
  72                 sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
  73                 host->sg_ptr = &host->bounce_sg;
  74                 sg = host->sg_ptr;
  75         }
  76
  77         ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_FROM_DEVICE);
  78         if (ret > 0)
  79                 desc = chan->device->device_prep_slave_sg(chan, sg, ret,
  80                         DMA_FROM_DEVICE, DMA_CTRL_ACK);
  81
  82         if (desc) {
  83                 cookie = dmaengine_submit(desc);
  84                 if (cookie < 0) {
  85                         desc = NULL;
  86                         ret = cookie;
  87                 }
  88         }
  89         dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n",
  90                 __func__, host->sg_len, ret, cookie, host->mrq);
  91
  92 pio:
  93         if (!desc) {
  94                 /* DMA failed, fall back to PIO */
  95                 if (ret >= 0)
  96                         ret = -EIO;
  97                 host->chan_rx = NULL;
  98                 dma_release_channel(chan);
  99                 /* Free the Tx channel too */
 100                 chan = host->chan_tx;
 101                 if (chan) {
 102                         host->chan_tx = NULL;
 103                         dma_release_channel(chan);
 104                 }
 105                 dev_warn(&host->pdev->dev,
 106                          "DMA failed: %d, falling back to PIO\n", ret);
 107                 tmio_mmc_enable_dma(host, false);
 108         }
 109
 110         dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d, sg[%d]\n", __func__,
 111                 desc, cookie, host->sg_len);
 112 }
 113
 114 static void tmio_mmc_start_dma_tx(struct tmio_mmc_host *host)
 115 {
 116         struct scatterlist *sg = host->sg_ptr, *sg_tmp;
 117         struct dma_async_tx_descriptor *desc = NULL;
 118         struct dma_chan *chan = host->chan_tx;
 119         struct tmio_mmc_data *pdata = host->pdata;
 120         dma_cookie_t cookie;
 121         int ret, i;
 122         bool aligned = true, multiple = true;
 123         unsigned int align = (1 << pdata->dma->alignment_shift) - 1;
 124
 125         for_each_sg(sg, sg_tmp, host->sg_len, i) {
 126                 if (sg_tmp->offset & align)
 127                         aligned = false;
 128                 if (sg_tmp->length & align) {
 129                         multiple = false;
 130                         break;
 131                 }
 132         }
 133
 134         if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_CACHE_SIZE ||
 135                           (align & PAGE_MASK))) || !multiple) {
 136                 ret = -EINVAL;
 137                 goto pio;
 138         }
 139
 140         if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
 141                 host->force_pio = true;
 142                 return;
 143         }
 144
 145         tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_TXRQ);
 146
 147         /* The only sg element can be unaligned, use our bounce buffer then */
 148         if (!aligned) {
 149                 unsigned long flags;
 150                 void *sg_vaddr = tmio_mmc_kmap_atomic(sg, &flags);
 151                 sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
 152                 memcpy(host->bounce_buf, sg_vaddr, host->bounce_sg.length);
 153                 tmio_mmc_kunmap_atomic(sg, &flags, sg_vaddr);
 154                 host->sg_ptr = &host->bounce_sg;
 155                 sg = host->sg_ptr;
 156         }
 157
 158         ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_TO_DEVICE);
 159         if (ret > 0)
 160                 desc = chan->device->device_prep_slave_sg(chan, sg, ret,
 161                         DMA_TO_DEVICE, DMA_CTRL_ACK);
 162
 163         if (desc) {
 164                 cookie = dmaengine_submit(desc);
 165                 if (cookie < 0) {
 166                         desc = NULL;
 167                         ret = cookie;
 168                 }
 169         }
 170         dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n",
 171                 __func__, host->sg_len, ret, cookie, host->mrq);
 172
 173 pio:
 174         if (!desc) {
 175                 /* DMA failed, fall back to PIO */
 176                 if (ret >= 0)
 177                         ret = -EIO;
 178                 host->chan_tx = NULL;
 179                 dma_release_channel(chan);
 180                 /* Free the Rx channel too */
 181                 chan = host->chan_rx;
 182                 if (chan) {
 183                         host->chan_rx = NULL;
 184                         dma_release_channel(chan);
 185                 }
 186                 dev_warn(&host->pdev->dev,
 187                          "DMA failed: %d, falling back to PIO\n", ret);
 188                 tmio_mmc_enable_dma(host, false);
 189         }
 190
 191         dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d\n", __func__,
 192                 desc, cookie);
 193 }
 194
 195 void tmio_mmc_start_dma(struct tmio_mmc_host *host,
 196                                struct mmc_data *data)
 197 {
 198         if (data->flags & MMC_DATA_READ) {
 199                 if (host->chan_rx)
 200                         tmio_mmc_start_dma_rx(host);
 201         } else {
 202                 if (host->chan_tx)
 203                         tmio_mmc_start_dma_tx(host);
 204         }
 205 }
 206
 207 static void tmio_mmc_issue_tasklet_fn(unsigned long priv)
 208 {
 209         struct tmio_mmc_host *host = (struct tmio_mmc_host *)priv;
 210         struct dma_chan *chan = NULL;
 211
 212         spin_lock_irq(&host->lock);
 213
 214         if (host && host->data) {
 215                 if (host->data->flags & MMC_DATA_READ)
 216                         chan = host->chan_rx;
 217                 else
 218                         chan = host->chan_tx;
 219         }
 220
 221         spin_unlock_irq(&host->lock);
 222
 223         tmio_mmc_enable_mmc_irqs(host, TMIO_STAT_DATAEND);
 224
 225         if (chan)
 226                 dma_async_issue_pending(chan);
 227 }
 228
 229 static void tmio_mmc_tasklet_fn(unsigned long arg)
 230 {
 231         struct tmio_mmc_host *host = (struct tmio_mmc_host *)arg;
 232
 233         spin_lock_irq(&host->lock);
 234
 235         if (!host->data)
 236                 goto out;
 237
 238         if (host->data->flags & MMC_DATA_READ)
 239                 dma_unmap_sg(host->chan_rx->device->dev,
 240                              host->sg_ptr, host->sg_len,
 241                              DMA_FROM_DEVICE);
 242         else
 243                 dma_unmap_sg(host->chan_tx->device->dev,
 244                              host->sg_ptr, host->sg_len,
 245                              DMA_TO_DEVICE);
 246
 247         tmio_mmc_do_data_irq(host);
 248 out:
 249         spin_unlock_irq(&host->lock);
 250 }
 251
 252 /* It might be necessary to make filter MFD specific */
 253 static bool tmio_mmc_filter(struct dma_chan *chan, void *arg)
 254 {
 255         dev_dbg(chan->device->dev, "%s: slave data %p\n", __func__, arg);
 256         chan->private = arg;
 257         return true;
 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 (!pdata->dma)
 264                 return;
 265
 266         if (!host->chan_tx && !host->chan_rx) {
 267                 dma_cap_mask_t mask;
 268
 269                 dma_cap_zero(mask);
 270                 dma_cap_set(DMA_SLAVE, mask);
 271
 272                 host->chan_tx = dma_request_channel(mask, tmio_mmc_filter,
 273                                                     pdata->dma->chan_priv_tx);
 274                 dev_dbg(&host->pdev->dev, "%s: TX: got channel %p\n", __func__,
 275                         host->chan_tx);
 276
 277                 if (!host->chan_tx)
 278                         return;
 279
 280                 host->chan_rx = dma_request_channel(mask, tmio_mmc_filter,
 281                                                     pdata->dma->chan_priv_rx);
 282                 dev_dbg(&host->pdev->dev, "%s: RX: got channel %p\n", __func__,
 283                         host->chan_rx);
 284
 285                 if (!host->chan_rx)
 286                         goto ereqrx;
 287
 288                 host->bounce_buf = (u8 *)__get_free_page(GFP_KERNEL | GFP_DMA);
 289                 if (!host->bounce_buf)
 290                         goto ebouncebuf;
 291
 292                 tasklet_init(&host->dma_complete, tmio_mmc_tasklet_fn, (unsigned long)host);
 293                 tasklet_init(&host->dma_issue, tmio_mmc_issue_tasklet_fn, (unsigned long)host);
 294         }
 295
 296         tmio_mmc_enable_dma(host, true);
 297
 298         return;
 299
 300 ebouncebuf:
 301         dma_release_channel(host->chan_rx);
 302         host->chan_rx = NULL;
 303 ereqrx:
 304         dma_release_channel(host->chan_tx);
 305         host->chan_tx = NULL;
 306 }
 307
 308 void tmio_mmc_release_dma(struct tmio_mmc_host *host)
 309 {
 310         if (host->chan_tx) {
 311                 struct dma_chan *chan = host->chan_tx;
 312                 host->chan_tx = NULL;
 313                 dma_release_channel(chan);
 314         }
 315         if (host->chan_rx) {
 316                 struct dma_chan *chan = host->chan_rx;
 317                 host->chan_rx = NULL;
 318                 dma_release_channel(chan);
 319         }
 320         if (host->bounce_buf) {
 321                 free_pages((unsigned long)host->bounce_buf, 0);
 322                 host->bounce_buf = NULL;
 323         }
 324 }