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/dmaengine.h>
  15 #include <linux/mfd/tmio.h>
  16 #include <linux/mmc/host.h>
  17 #include <linux/mmc/tmio.h>
  18 #include <linux/pagemap.h>
  19 #include <linux/scatterlist.h>
  20
  21 #include "tmio_mmc.h"
  22
  23 #define TMIO_MMC_MIN_DMA_LEN 8
  24
  25 static void tmio_mmc_enable_dma(struct tmio_mmc_host *host, bool enable)
  26 {
  27 #if defined(CONFIG_SUPERH) || defined(CONFIG_ARCH_SHMOBILE)
  28         /* Switch DMA mode on or off - SuperH specific? */
  29         writew(enable ? 2 : 0, host->ctl + (0xd8 << host->bus_shift));
  30 #endif
  31 }
  32
  33 static void tmio_mmc_start_dma_rx(struct tmio_mmc_host *host)
  34 {
  35         struct scatterlist *sg = host->sg_ptr, *sg_tmp;
  36         struct dma_async_tx_descriptor *desc = NULL;
  37         struct dma_chan *chan = host->chan_rx;
  38         struct tmio_mmc_data *pdata = host->pdata;
  39         dma_cookie_t cookie;
  40         int ret, i;
  41         bool aligned = true, multiple = true;
  42         unsigned int align = (1 << pdata->dma->alignment_shift) - 1;
  43
  44         for_each_sg(sg, sg_tmp, host->sg_len, i) {
  45                 if (sg_tmp->offset & align)
  46                         aligned = false;
  47                 if (sg_tmp->length & align) {
  48                         multiple = false;
  49                         break;
  50                 }
  51         }
  52
  53         if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_CACHE_SIZE ||
  54                           (align & PAGE_MASK))) || !multiple) {
  55                 ret = -EINVAL;
  56                 goto pio;
  57         }
  58
  59         if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
  60                 host->force_pio = true;
  61                 return;
  62         }
  63
  64         tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_RXRDY);
  65
  66         /* The only sg element can be unaligned, use our bounce buffer then */
  67         if (!aligned) {
  68                 sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
  69                 host->sg_ptr = &host->bounce_sg;
  70                 sg = host->sg_ptr;
  71         }
  72
  73         ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_FROM_DEVICE);
  74         if (ret > 0)
  75                 desc = chan->device->device_prep_slave_sg(chan, sg, ret,
  76                         DMA_FROM_DEVICE, DMA_CTRL_ACK);
  77
  78         if (desc) {
  79                 cookie = dmaengine_submit(desc);
  80                 if (cookie < 0) {
  81                         desc = NULL;
  82                         ret = cookie;
  83                 }
  84         }
  85         dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n",
  86                 __func__, host->sg_len, ret, cookie, host->mrq);
  87
  88 pio:
  89         if (!desc) {
  90                 /* DMA failed, fall back to PIO */
  91                 if (ret >= 0)
  92                         ret = -EIO;
  93                 host->chan_rx = NULL;
  94                 dma_release_channel(chan);
  95                 /* Free the Tx channel too */
  96                 chan = host->chan_tx;
  97                 if (chan) {
  98                         host->chan_tx = NULL;
  99                         dma_release_channel(chan);
 100                 }
 101                 dev_warn(&host->pdev->dev,
 102                          "DMA failed: %d, falling back to PIO\n", ret);
 103                 tmio_mmc_enable_dma(host, false);
 104         }
 105
 106         dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d, sg[%d]\n", __func__,
 107                 desc, cookie, host->sg_len);
 108 }
 109
 110 static void tmio_mmc_start_dma_tx(struct tmio_mmc_host *host)
 111 {
 112         struct scatterlist *sg = host->sg_ptr, *sg_tmp;
 113         struct dma_async_tx_descriptor *desc = NULL;
 114         struct dma_chan *chan = host->chan_tx;
 115         struct tmio_mmc_data *pdata = host->pdata;
 116         dma_cookie_t cookie;
 117         int ret, i;
 118         bool aligned = true, multiple = true;
 119         unsigned int align = (1 << pdata->dma->alignment_shift) - 1;
 120
 121         for_each_sg(sg, sg_tmp, host->sg_len, i) {
 122                 if (sg_tmp->offset & align)
 123                         aligned = false;
 124                 if (sg_tmp->length & align) {
 125                         multiple = false;
 126                         break;
 127                 }
 128         }
 129
 130         if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_CACHE_SIZE ||
 131                           (align & PAGE_MASK))) || !multiple) {
 132                 ret = -EINVAL;
 133                 goto pio;
 134         }
 135
 136         if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
 137                 host->force_pio = true;
 138                 return;
 139         }
 140
 141         tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_TXRQ);
 142
 143         /* The only sg element can be unaligned, use our bounce buffer then */
 144         if (!aligned) {
 145                 unsigned long flags;
 146                 void *sg_vaddr = tmio_mmc_kmap_atomic(sg, &flags);
 147                 sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
 148                 memcpy(host->bounce_buf, sg_vaddr, host->bounce_sg.length);
 149                 tmio_mmc_kunmap_atomic(sg, &flags, sg_vaddr);
 150                 host->sg_ptr = &host->bounce_sg;
 151                 sg = host->sg_ptr;
 152         }
 153
 154         ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_TO_DEVICE);
 155         if (ret > 0)
 156                 desc = chan->device->device_prep_slave_sg(chan, sg, ret,
 157                         DMA_TO_DEVICE, DMA_CTRL_ACK);
 158
 159         if (desc) {
 160                 cookie = dmaengine_submit(desc);
 161                 if (cookie < 0) {
 162                         desc = NULL;
 163                         ret = cookie;
 164                 }
 165         }
 166         dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n",
 167                 __func__, host->sg_len, ret, cookie, host->mrq);
 168
 169 pio:
 170         if (!desc) {
 171                 /* DMA failed, fall back to PIO */
 172                 if (ret >= 0)
 173                         ret = -EIO;
 174                 host->chan_tx = NULL;
 175                 dma_release_channel(chan);
 176                 /* Free the Rx channel too */
 177                 chan = host->chan_rx;
 178                 if (chan) {
 179                         host->chan_rx = NULL;
 180                         dma_release_channel(chan);
 181                 }
 182                 dev_warn(&host->pdev->dev,
 183                          "DMA failed: %d, falling back to PIO\n", ret);
 184                 tmio_mmc_enable_dma(host, false);
 185         }
 186
 187         dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d\n", __func__,
 188                 desc, cookie);
 189 }
 190
 191 void tmio_mmc_start_dma(struct tmio_mmc_host *host,
 192                                struct mmc_data *data)
 193 {
 194         if (data->flags & MMC_DATA_READ) {
 195                 if (host->chan_rx)
 196                         tmio_mmc_start_dma_rx(host);
 197         } else {
 198                 if (host->chan_tx)
 199                         tmio_mmc_start_dma_tx(host);
 200         }
 201 }
 202
 203 static void tmio_mmc_issue_tasklet_fn(unsigned long priv)
 204 {
 205         struct tmio_mmc_host *host = (struct tmio_mmc_host *)priv;
 206         struct dma_chan *chan = NULL;
 207
 208         spin_lock_irq(&host->lock);
 209
 210         if (host && host->data) {
 211                 if (host->data->flags & MMC_DATA_READ)
 212                         chan = host->chan_rx;
 213                 else
 214                         chan = host->chan_tx;
 215         }
 216
 217         spin_unlock_irq(&host->lock);
 218
 219         tmio_mmc_enable_mmc_irqs(host, TMIO_STAT_DATAEND);
 220
 221         if (chan)
 222                 dma_async_issue_pending(chan);
 223 }
 224
 225 static void tmio_mmc_tasklet_fn(unsigned long arg)
 226 {
 227         struct tmio_mmc_host *host = (struct tmio_mmc_host *)arg;
 228
 229         spin_lock_irq(&host->lock);
 230
 231         if (!host->data)
 232                 goto out;
 233
 234         if (host->data->flags & MMC_DATA_READ)
 235                 dma_unmap_sg(host->chan_rx->device->dev,
 236                              host->sg_ptr, host->sg_len,
 237                              DMA_FROM_DEVICE);
 238         else
 239                 dma_unmap_sg(host->chan_tx->device->dev,
 240                              host->sg_ptr, host->sg_len,
 241                              DMA_TO_DEVICE);
 242
 243         tmio_mmc_do_data_irq(host);
 244 out:
 245         spin_unlock_irq(&host->lock);
 246 }
 247
 248 /* It might be necessary to make filter MFD specific */
 249 static bool tmio_mmc_filter(struct dma_chan *chan, void *arg)
 250 {
 251         dev_dbg(chan->device->dev, "%s: slave data %p\n", __func__, arg);
 252         chan->private = arg;
 253         return true;
 254 }
 255
 256 void tmio_mmc_request_dma(struct tmio_mmc_host *host, struct tmio_mmc_data *pdata)
 257 {
 258         /* We can only either use DMA for both Tx and Rx or not use it at all */
 259         if (!pdata->dma)
 260                 return;
 261
 262         if (!host->chan_tx && !host->chan_rx) {
 263                 dma_cap_mask_t mask;
 264
 265                 dma_cap_zero(mask);
 266                 dma_cap_set(DMA_SLAVE, mask);
 267
 268                 host->chan_tx = dma_request_channel(mask, tmio_mmc_filter,
 269                                                     pdata->dma->chan_priv_tx);
 270                 dev_dbg(&host->pdev->dev, "%s: TX: got channel %p\n", __func__,
 271                         host->chan_tx);
 272
 273                 if (!host->chan_tx)
 274                         return;
 275
 276                 host->chan_rx = dma_request_channel(mask, tmio_mmc_filter,
 277                                                     pdata->dma->chan_priv_rx);
 278                 dev_dbg(&host->pdev->dev, "%s: RX: got channel %p\n", __func__,
 279                         host->chan_rx);
 280
 281                 if (!host->chan_rx)
 282                         goto ereqrx;
 283
 284                 host->bounce_buf = (u8 *)__get_free_page(GFP_KERNEL | GFP_DMA);
 285                 if (!host->bounce_buf)
 286                         goto ebouncebuf;
 287
 288                 tasklet_init(&host->dma_complete, tmio_mmc_tasklet_fn, (unsigned long)host);
 289                 tasklet_init(&host->dma_issue, tmio_mmc_issue_tasklet_fn, (unsigned long)host);
 290         }
 291
 292         tmio_mmc_enable_dma(host, true);
 293
 294         return;
 295
 296 ebouncebuf:
 297         dma_release_channel(host->chan_rx);
 298         host->chan_rx = NULL;
 299 ereqrx:
 300         dma_release_channel(host->chan_tx);
 301         host->chan_tx = NULL;
 302 }
 303
 304 void tmio_mmc_release_dma(struct tmio_mmc_host *host)
 305 {
 306         if (host->chan_tx) {
 307                 struct dma_chan *chan = host->chan_tx;
 308                 host->chan_tx = NULL;
 309                 dma_release_channel(chan);
 310         }
 311         if (host->chan_rx) {
 312                 struct dma_chan *chan = host->chan_rx;
 313                 host->chan_rx = NULL;
 314                 dma_release_channel(chan);
 315         }
 316         if (host->bounce_buf) {
 317                 free_pages((unsigned long)host->bounce_buf, 0);
 318                 host->bounce_buf = NULL;
 319         }
 320 }