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 static void tmio_mmc_enable_dma(struct tmio_mmc_host *host, bool enable)
  27 {
  28 #if defined(CONFIG_SUPERH) || defined(CONFIG_ARCH_SHMOBILE)
  29         /* Switch DMA mode on or off - SuperH specific? */
  30         writew(enable ? 2 : 0, host->ctl + (0xd8 << host->bus_shift));
  31 #endif
  32 }
  33
  34 static void tmio_mmc_start_dma_rx(struct tmio_mmc_host *host)
  35 {
  36         struct scatterlist *sg = host->sg_ptr, *sg_tmp;
  37         struct dma_async_tx_descriptor *desc = NULL;
  38         struct dma_chan *chan = host->chan_rx;
  39         struct tmio_mmc_data *pdata = host->pdata;
  40         dma_cookie_t cookie;
  41         int ret, i;
  42         bool aligned = true, multiple = true;
  43         unsigned int align = (1 << pdata->dma->alignment_shift) - 1;
  44
  45         for_each_sg(sg, sg_tmp, host->sg_len, i) {
  46                 if (sg_tmp->offset & align)
  47                         aligned = false;
  48                 if (sg_tmp->length & align) {
  49                         multiple = false;
  50                         break;
  51                 }
  52         }
  53
  54         if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_CACHE_SIZE ||
  55                           (align & PAGE_MASK))) || !multiple) {
  56                 ret = -EINVAL;
  57                 goto pio;
  58         }
  59
  60         if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
  61                 host->force_pio = true;
  62                 return;
  63         }
  64
  65         tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_RXRDY);
  66
  67         /* The only sg element can be unaligned, use our bounce buffer then */
  68         if (!aligned) {
  69                 sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
  70                 host->sg_ptr = &host->bounce_sg;
  71                 sg = host->sg_ptr;
  72         }
  73
  74         ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_FROM_DEVICE);
  75         if (ret > 0)
  76                 desc = chan->device->device_prep_slave_sg(chan, sg, ret,
  77                         DMA_FROM_DEVICE, DMA_CTRL_ACK);
  78
  79         if (desc) {
  80                 cookie = dmaengine_submit(desc);
  81                 if (cookie < 0) {
  82                         desc = NULL;
  83                         ret = cookie;
  84                 }
  85         }
  86         dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n",
  87                 __func__, host->sg_len, ret, cookie, host->mrq);
  88
  89 pio:
  90         if (!desc) {
  91                 /* DMA failed, fall back to PIO */
  92                 if (ret >= 0)
  93                         ret = -EIO;
  94                 host->chan_rx = NULL;
  95                 dma_release_channel(chan);
  96                 /* Free the Tx channel too */
  97                 chan = host->chan_tx;
  98                 if (chan) {
  99                         host->chan_tx = NULL;
 100                         dma_release_channel(chan);
 101                 }
 102                 dev_warn(&host->pdev->dev,
 103                          "DMA failed: %d, falling back to PIO\n", ret);
 104                 tmio_mmc_enable_dma(host, false);
 105         }
 106
 107         dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d, sg[%d]\n", __func__,
 108                 desc, cookie, host->sg_len);
 109 }
 110
 111 static void tmio_mmc_start_dma_tx(struct tmio_mmc_host *host)
 112 {
 113         struct scatterlist *sg = host->sg_ptr, *sg_tmp;
 114         struct dma_async_tx_descriptor *desc = NULL;
 115         struct dma_chan *chan = host->chan_tx;
 116         struct tmio_mmc_data *pdata = host->pdata;
 117         dma_cookie_t cookie;
 118         int ret, i;
 119         bool aligned = true, multiple = true;
 120         unsigned int align = (1 << pdata->dma->alignment_shift) - 1;
 121
 122         for_each_sg(sg, sg_tmp, host->sg_len, i) {
 123                 if (sg_tmp->offset & align)
 124                         aligned = false;
 125                 if (sg_tmp->length & align) {
 126                         multiple = false;
 127                         break;
 128                 }
 129         }
 130
 131         if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_CACHE_SIZE ||
 132                           (align & PAGE_MASK))) || !multiple) {
 133                 ret = -EINVAL;
 134                 goto pio;
 135         }
 136
 137         if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
 138                 host->force_pio = true;
 139                 return;
 140         }
 141
 142         tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_TXRQ);
 143
 144         /* The only sg element can be unaligned, use our bounce buffer then */
 145         if (!aligned) {
 146                 unsigned long flags;
 147                 void *sg_vaddr = tmio_mmc_kmap_atomic(sg, &flags);
 148                 sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
 149                 memcpy(host->bounce_buf, sg_vaddr, host->bounce_sg.length);
 150                 tmio_mmc_kunmap_atomic(sg, &flags, sg_vaddr);
 151                 host->sg_ptr = &host->bounce_sg;
 152                 sg = host->sg_ptr;
 153         }
 154
 155         ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_TO_DEVICE);
 156         if (ret > 0)
 157                 desc = chan->device->device_prep_slave_sg(chan, sg, ret,
 158                         DMA_TO_DEVICE, DMA_CTRL_ACK);
 159
 160         if (desc) {
 161                 cookie = dmaengine_submit(desc);
 162                 if (cookie < 0) {
 163                         desc = NULL;
 164                         ret = cookie;
 165                 }
 166         }
 167         dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n",
 168                 __func__, host->sg_len, ret, cookie, host->mrq);
 169
 170 pio:
 171         if (!desc) {
 172                 /* DMA failed, fall back to PIO */
 173                 if (ret >= 0)
 174                         ret = -EIO;
 175                 host->chan_tx = NULL;
 176                 dma_release_channel(chan);
 177                 /* Free the Rx channel too */
 178                 chan = host->chan_rx;
 179                 if (chan) {
 180                         host->chan_rx = NULL;
 181                         dma_release_channel(chan);
 182                 }
 183                 dev_warn(&host->pdev->dev,
 184                          "DMA failed: %d, falling back to PIO\n", ret);
 185                 tmio_mmc_enable_dma(host, false);
 186         }
 187
 188         dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d\n", __func__,
 189                 desc, cookie);
 190 }
 191
 192 void tmio_mmc_start_dma(struct tmio_mmc_host *host,
 193                                struct mmc_data *data)
 194 {
 195         if (data->flags & MMC_DATA_READ) {
 196                 if (host->chan_rx)
 197                         tmio_mmc_start_dma_rx(host);
 198         } else {
 199                 if (host->chan_tx)
 200                         tmio_mmc_start_dma_tx(host);
 201         }
 202 }
 203
 204 static void tmio_mmc_issue_tasklet_fn(unsigned long priv)
 205 {
 206         struct tmio_mmc_host *host = (struct tmio_mmc_host *)priv;
 207         struct dma_chan *chan = NULL;
 208
 209         spin_lock_irq(&host->lock);
 210
 211         if (host && host->data) {
 212                 if (host->data->flags & MMC_DATA_READ)
 213                         chan = host->chan_rx;
 214                 else
 215                         chan = host->chan_tx;
 216         }
 217
 218         spin_unlock_irq(&host->lock);
 219
 220         tmio_mmc_enable_mmc_irqs(host, TMIO_STAT_DATAEND);
 221
 222         if (chan)
 223                 dma_async_issue_pending(chan);
 224 }
 225
 226 static void tmio_mmc_tasklet_fn(unsigned long arg)
 227 {
 228         struct tmio_mmc_host *host = (struct tmio_mmc_host *)arg;
 229
 230         spin_lock_irq(&host->lock);
 231
 232         if (!host->data)
 233                 goto out;
 234
 235         if (host->data->flags & MMC_DATA_READ)
 236                 dma_unmap_sg(host->chan_rx->device->dev,
 237                              host->sg_ptr, host->sg_len,
 238                              DMA_FROM_DEVICE);
 239         else
 240                 dma_unmap_sg(host->chan_tx->device->dev,
 241                              host->sg_ptr, host->sg_len,
 242                              DMA_TO_DEVICE);
 243
 244         tmio_mmc_do_data_irq(host);
 245 out:
 246         spin_unlock_irq(&host->lock);
 247 }
 248
 249 /* It might be necessary to make filter MFD specific */
 250 static bool tmio_mmc_filter(struct dma_chan *chan, void *arg)
 251 {
 252         dev_dbg(chan->device->dev, "%s: slave data %p\n", __func__, arg);
 253         chan->private = arg;
 254         return true;
 255 }
 256
 257 void tmio_mmc_request_dma(struct tmio_mmc_host *host, struct tmio_mmc_data *pdata)
 258 {
 259         /* We can only either use DMA for both Tx and Rx or not use it at all */
 260         if (!pdata->dma)
 261                 return;
 262
 263         if (!host->chan_tx && !host->chan_rx) {
 264                 dma_cap_mask_t mask;
 265
 266                 dma_cap_zero(mask);
 267                 dma_cap_set(DMA_SLAVE, mask);
 268
 269                 host->chan_tx = dma_request_channel(mask, tmio_mmc_filter,
 270                                                     pdata->dma->chan_priv_tx);
 271                 dev_dbg(&host->pdev->dev, "%s: TX: got channel %p\n", __func__,
 272                         host->chan_tx);
 273
 274                 if (!host->chan_tx)
 275                         return;
 276
 277                 host->chan_rx = dma_request_channel(mask, tmio_mmc_filter,
 278                                                     pdata->dma->chan_priv_rx);
 279                 dev_dbg(&host->pdev->dev, "%s: RX: got channel %p\n", __func__,
 280                         host->chan_rx);
 281
 282                 if (!host->chan_rx)
 283                         goto ereqrx;
 284
 285                 host->bounce_buf = (u8 *)__get_free_page(GFP_KERNEL | GFP_DMA);
 286                 if (!host->bounce_buf)
 287                         goto ebouncebuf;
 288
 289                 tasklet_init(&host->dma_complete, tmio_mmc_tasklet_fn, (unsigned long)host);
 290                 tasklet_init(&host->dma_issue, tmio_mmc_issue_tasklet_fn, (unsigned long)host);
 291         }
 292
 293         tmio_mmc_enable_dma(host, true);
 294
 295         return;
 296
 297 ebouncebuf:
 298         dma_release_channel(host->chan_rx);
 299         host->chan_rx = NULL;
 300 ereqrx:
 301         dma_release_channel(host->chan_tx);
 302         host->chan_tx = NULL;
 303 }
 304
 305 void tmio_mmc_release_dma(struct tmio_mmc_host *host)
 306 {
 307         if (host->chan_tx) {
 308                 struct dma_chan *chan = host->chan_tx;
 309                 host->chan_tx = NULL;
 310                 dma_release_channel(chan);
 311         }
 312         if (host->chan_rx) {
 313                 struct dma_chan *chan = host->chan_rx;
 314                 host->chan_rx = NULL;
 315                 dma_release_channel(chan);
 316         }
 317         if (host->bounce_buf) {
 318                 free_pages((unsigned long)host->bounce_buf, 0);
 319                 host->bounce_buf = NULL;
 320         }
 321 }