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 void tmio_mmc_abort_dma(struct tmio_mmc_host *host)
  38 {
  39         tmio_mmc_enable_dma(host, false);
  40
  41         if (host->chan_rx)
  42                 dmaengine_terminate_all(host->chan_rx);
  43         if (host->chan_tx)
  44                 dmaengine_terminate_all(host->chan_tx);
  45
  46         tmio_mmc_enable_dma(host, true);
  47 }
  48
  49 static void tmio_mmc_start_dma_rx(struct tmio_mmc_host *host)
  50 {
  51         struct scatterlist *sg = host->sg_ptr, *sg_tmp;
  52         struct dma_async_tx_descriptor *desc = NULL;
  53         struct dma_chan *chan = host->chan_rx;
  54         struct tmio_mmc_data *pdata = host->pdata;
  55         dma_cookie_t cookie;
  56         int ret, i;
  57         bool aligned = true, multiple = true;
  58         unsigned int align = (1 << pdata->dma->alignment_shift) - 1;
  59
  60         for_each_sg(sg, sg_tmp, host->sg_len, i) {
  61                 if (sg_tmp->offset & align)
  62                         aligned = false;
  63                 if (sg_tmp->length & align) {
  64                         multiple = false;
  65                         break;
  66                 }
  67         }
  68
  69         if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_CACHE_SIZE ||
  70                           (align & PAGE_MASK))) || !multiple) {
  71                 ret = -EINVAL;
  72                 goto pio;
  73         }
  74
  75         if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
  76                 host->force_pio = true;
  77                 return;
  78         }
  79
  80         tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_RXRDY);
  81
  82         /* The only sg element can be unaligned, use our bounce buffer then */
  83         if (!aligned) {
  84                 sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
  85                 host->sg_ptr = &host->bounce_sg;
  86                 sg = host->sg_ptr;
  87         }
  88
  89         ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_FROM_DEVICE);
  90         if (ret > 0)
  91                 desc = dmaengine_prep_slave_sg(chan, sg, ret,
  92                         DMA_DEV_TO_MEM, DMA_CTRL_ACK);
  93
  94         if (desc) {
  95                 cookie = dmaengine_submit(desc);
  96                 if (cookie < 0) {
  97                         desc = NULL;
  98                         ret = cookie;
  99                 }
 100         }
 101         dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n",
 102                 __func__, host->sg_len, ret, cookie, host->mrq);
 103
 104 pio:
 105         if (!desc) {
 106                 /* DMA failed, fall back to PIO */
 107                 if (ret >= 0)
 108                         ret = -EIO;
 109                 host->chan_rx = NULL;
 110                 dma_release_channel(chan);
 111                 /* Free the Tx channel too */
 112                 chan = host->chan_tx;
 113                 if (chan) {
 114                         host->chan_tx = NULL;
 115                         dma_release_channel(chan);
 116                 }
 117                 dev_warn(&host->pdev->dev,
 118                          "DMA failed: %d, falling back to PIO\n", ret);
 119                 tmio_mmc_enable_dma(host, false);
 120         }
 121
 122         dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d, sg[%d]\n", __func__,
 123                 desc, cookie, host->sg_len);
 124 }
 125
 126 static void tmio_mmc_start_dma_tx(struct tmio_mmc_host *host)
 127 {
 128         struct scatterlist *sg = host->sg_ptr, *sg_tmp;
 129         struct dma_async_tx_descriptor *desc = NULL;
 130         struct dma_chan *chan = host->chan_tx;
 131         struct tmio_mmc_data *pdata = host->pdata;
 132         dma_cookie_t cookie;
 133         int ret, i;
 134         bool aligned = true, multiple = true;
 135         unsigned int align = (1 << pdata->dma->alignment_shift) - 1;
 136
 137         for_each_sg(sg, sg_tmp, host->sg_len, i) {
 138                 if (sg_tmp->offset & align)
 139                         aligned = false;
 140                 if (sg_tmp->length & align) {
 141                         multiple = false;
 142                         break;
 143                 }
 144         }
 145
 146         if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_CACHE_SIZE ||
 147                           (align & PAGE_MASK))) || !multiple) {
 148                 ret = -EINVAL;
 149                 goto pio;
 150         }
 151
 152         if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
 153                 host->force_pio = true;
 154                 return;
 155         }
 156
 157         tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_TXRQ);
 158
 159         /* The only sg element can be unaligned, use our bounce buffer then */
 160         if (!aligned) {
 161                 unsigned long flags;
 162                 void *sg_vaddr = tmio_mmc_kmap_atomic(sg, &flags);
 163                 sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
 164                 memcpy(host->bounce_buf, sg_vaddr, host->bounce_sg.length);
 165                 tmio_mmc_kunmap_atomic(sg, &flags, sg_vaddr);
 166                 host->sg_ptr = &host->bounce_sg;
 167                 sg = host->sg_ptr;
 168         }
 169
 170         ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_TO_DEVICE);
 171         if (ret > 0)
 172                 desc = dmaengine_prep_slave_sg(chan, sg, ret,
 173                         DMA_MEM_TO_DEV, DMA_CTRL_ACK);
 174
 175         if (desc) {
 176                 cookie = dmaengine_submit(desc);
 177                 if (cookie < 0) {
 178                         desc = NULL;
 179                         ret = cookie;
 180                 }
 181         }
 182         dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n",
 183                 __func__, host->sg_len, ret, cookie, host->mrq);
 184
 185 pio:
 186         if (!desc) {
 187                 /* DMA failed, fall back to PIO */
 188                 if (ret >= 0)
 189                         ret = -EIO;
 190                 host->chan_tx = NULL;
 191                 dma_release_channel(chan);
 192                 /* Free the Rx channel too */
 193                 chan = host->chan_rx;
 194                 if (chan) {
 195                         host->chan_rx = NULL;
 196                         dma_release_channel(chan);
 197                 }
 198                 dev_warn(&host->pdev->dev,
 199                          "DMA failed: %d, falling back to PIO\n", ret);
 200                 tmio_mmc_enable_dma(host, false);
 201         }
 202
 203         dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d\n", __func__,
 204                 desc, cookie);
 205 }
 206
 207 void tmio_mmc_start_dma(struct tmio_mmc_host *host,
 208                                struct mmc_data *data)
 209 {
 210         if (data->flags & MMC_DATA_READ) {
 211                 if (host->chan_rx)
 212                         tmio_mmc_start_dma_rx(host);
 213         } else {
 214                 if (host->chan_tx)
 215                         tmio_mmc_start_dma_tx(host);
 216         }
 217 }
 218
 219 static void tmio_mmc_issue_tasklet_fn(unsigned long priv)
 220 {
 221         struct tmio_mmc_host *host = (struct tmio_mmc_host *)priv;
 222         struct dma_chan *chan = NULL;
 223
 224         spin_lock_irq(&host->lock);
 225
 226         if (host && host->data) {
 227                 if (host->data->flags & MMC_DATA_READ)
 228                         chan = host->chan_rx;
 229                 else
 230                         chan = host->chan_tx;
 231         }
 232
 233         spin_unlock_irq(&host->lock);
 234
 235         tmio_mmc_enable_mmc_irqs(host, TMIO_STAT_DATAEND);
 236
 237         if (chan)
 238                 dma_async_issue_pending(chan);
 239 }
 240
 241 static void tmio_mmc_tasklet_fn(unsigned long arg)
 242 {
 243         struct tmio_mmc_host *host = (struct tmio_mmc_host *)arg;
 244
 245         spin_lock_irq(&host->lock);
 246
 247         if (!host->data)
 248                 goto out;
 249
 250         if (host->data->flags & MMC_DATA_READ)
 251                 dma_unmap_sg(host->chan_rx->device->dev,
 252                              host->sg_ptr, host->sg_len,
 253                              DMA_FROM_DEVICE);
 254         else
 255                 dma_unmap_sg(host->chan_tx->device->dev,
 256                              host->sg_ptr, host->sg_len,
 257                              DMA_TO_DEVICE);
 258
 259         tmio_mmc_do_data_irq(host);
 260 out:
 261         spin_unlock_irq(&host->lock);
 262 }
 263
 264 /* It might be necessary to make filter MFD specific */
 265 static bool tmio_mmc_filter(struct dma_chan *chan, void *arg)
 266 {
 267         dev_dbg(chan->device->dev, "%s: slave data %p\n", __func__, arg);
 268         chan->private = arg;
 269         return true;
 270 }
 271
 272 void tmio_mmc_request_dma(struct tmio_mmc_host *host, struct tmio_mmc_data *pdata)
 273 {
 274         /* We can only either use DMA for both Tx and Rx or not use it at all */
 275         if (!pdata->dma)
 276                 return;
 277
 278         if (!host->chan_tx && !host->chan_rx) {
 279                 dma_cap_mask_t mask;
 280
 281                 dma_cap_zero(mask);
 282                 dma_cap_set(DMA_SLAVE, mask);
 283
 284                 host->chan_tx = dma_request_channel(mask, tmio_mmc_filter,
 285                                                     pdata->dma->chan_priv_tx);
 286                 dev_dbg(&host->pdev->dev, "%s: TX: got channel %p\n", __func__,
 287                         host->chan_tx);
 288
 289                 if (!host->chan_tx)
 290                         return;
 291
 292                 host->chan_rx = dma_request_channel(mask, tmio_mmc_filter,
 293                                                     pdata->dma->chan_priv_rx);
 294                 dev_dbg(&host->pdev->dev, "%s: RX: got channel %p\n", __func__,
 295                         host->chan_rx);
 296
 297                 if (!host->chan_rx)
 298                         goto ereqrx;
 299
 300                 host->bounce_buf = (u8 *)__get_free_page(GFP_KERNEL | GFP_DMA);
 301                 if (!host->bounce_buf)
 302                         goto ebouncebuf;
 303
 304                 tasklet_init(&host->dma_complete, tmio_mmc_tasklet_fn, (unsigned long)host);
 305                 tasklet_init(&host->dma_issue, tmio_mmc_issue_tasklet_fn, (unsigned long)host);
 306         }
 307
 308         tmio_mmc_enable_dma(host, true);
 309
 310         return;
 311
 312 ebouncebuf:
 313         dma_release_channel(host->chan_rx);
 314         host->chan_rx = NULL;
 315 ereqrx:
 316         dma_release_channel(host->chan_tx);
 317         host->chan_tx = NULL;
 318 }
 319
 320 void tmio_mmc_release_dma(struct tmio_mmc_host *host)
 321 {
 322         if (host->chan_tx) {
 323                 struct dma_chan *chan = host->chan_tx;
 324                 host->chan_tx = NULL;
 325                 dma_release_channel(chan);
 326         }
 327         if (host->chan_rx) {
 328                 struct dma_chan *chan = host->chan_rx;
 329                 host->chan_rx = NULL;
 330                 dma_release_channel(chan);
 331         }
 332         if (host->bounce_buf) {
 333                 free_pages((unsigned long)host->bounce_buf, 0);
 334                 host->bounce_buf = NULL;
 335         }
 336 }