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 void tmio_mmc_enable_dma(struct tmio_mmc_host *host, bool enable)
  26 {
  27         if (!host->chan_tx || !host->chan_rx)
  28                 return;
  29
  30 #if defined(CONFIG_SUPERH) || defined(CONFIG_ARCH_SHMOBILE)
  31         /* Switch DMA mode on or off - SuperH specific? */
  32         sd_ctrl_write16(host, CTL_DMA_ENABLE, enable ? 2 : 0);
  33 #endif
  34 }
  35
  36 static void tmio_mmc_start_dma_rx(struct tmio_mmc_host *host)
  37 {
  38         struct scatterlist *sg = host->sg_ptr, *sg_tmp;
  39         struct dma_async_tx_descriptor *desc = NULL;
  40         struct dma_chan *chan = host->chan_rx;
  41         struct tmio_mmc_data *pdata = host->pdata;
  42         dma_cookie_t cookie;
  43         int ret, i;
  44         bool aligned = true, multiple = true;
  45         unsigned int align = (1 << pdata->dma->alignment_shift) - 1;
  46
  47         for_each_sg(sg, sg_tmp, host->sg_len, i) {
  48                 if (sg_tmp->offset & align)
  49                         aligned = false;
  50                 if (sg_tmp->length & align) {
  51                         multiple = false;
  52                         break;
  53                 }
  54         }
  55
  56         if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_CACHE_SIZE ||
  57                           (align & PAGE_MASK))) || !multiple) {
  58                 ret = -EINVAL;
  59                 goto pio;
  60         }
  61
  62         if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
  63                 host->force_pio = true;
  64                 return;
  65         }
  66
  67         tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_RXRDY);
  68
  69         /* The only sg element can be unaligned, use our bounce buffer then */
  70         if (!aligned) {
  71                 sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
  72                 host->sg_ptr = &host->bounce_sg;
  73                 sg = host->sg_ptr;
  74         }
  75
  76         ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_FROM_DEVICE);
  77         if (ret > 0)
  78                 desc = chan->device->device_prep_slave_sg(chan, sg, ret,
  79                         DMA_FROM_DEVICE, DMA_CTRL_ACK);
  80
  81         if (desc) {
  82                 cookie = dmaengine_submit(desc);
  83                 if (cookie < 0) {
  84                         desc = NULL;
  85                         ret = cookie;
  86                 }
  87         }
  88         dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n",
  89                 __func__, host->sg_len, ret, cookie, host->mrq);
  90
  91 pio:
  92         if (!desc) {
  93                 /* DMA failed, fall back to PIO */
  94                 if (ret >= 0)
  95                         ret = -EIO;
  96                 host->chan_rx = NULL;
  97                 dma_release_channel(chan);
  98                 /* Free the Tx channel too */
  99                 chan = host->chan_tx;
 100                 if (chan) {
 101                         host->chan_tx = NULL;
 102                         dma_release_channel(chan);
 103                 }
 104                 dev_warn(&host->pdev->dev,
 105                          "DMA failed: %d, falling back to PIO\n", ret);
 106                 tmio_mmc_enable_dma(host, false);
 107         }
 108
 109         dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d, sg[%d]\n", __func__,
 110                 desc, cookie, host->sg_len);
 111 }
 112
 113 static void tmio_mmc_start_dma_tx(struct tmio_mmc_host *host)
 114 {
 115         struct scatterlist *sg = host->sg_ptr, *sg_tmp;
 116         struct dma_async_tx_descriptor *desc = NULL;
 117         struct dma_chan *chan = host->chan_tx;
 118         struct tmio_mmc_data *pdata = host->pdata;
 119         dma_cookie_t cookie;
 120         int ret, i;
 121         bool aligned = true, multiple = true;
 122         unsigned int align = (1 << pdata->dma->alignment_shift) - 1;
 123
 124         for_each_sg(sg, sg_tmp, host->sg_len, i) {
 125                 if (sg_tmp->offset & align)
 126                         aligned = false;
 127                 if (sg_tmp->length & align) {
 128                         multiple = false;
 129                         break;
 130                 }
 131         }
 132
 133         if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_CACHE_SIZE ||
 134                           (align & PAGE_MASK))) || !multiple) {
 135                 ret = -EINVAL;
 136                 goto pio;
 137         }
 138
 139         if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
 140                 host->force_pio = true;
 141                 return;
 142         }
 143
 144         tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_TXRQ);
 145
 146         /* The only sg element can be unaligned, use our bounce buffer then */
 147         if (!aligned) {
 148                 unsigned long flags;
 149                 void *sg_vaddr = tmio_mmc_kmap_atomic(sg, &flags);
 150                 sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
 151                 memcpy(host->bounce_buf, sg_vaddr, host->bounce_sg.length);
 152                 tmio_mmc_kunmap_atomic(sg, &flags, sg_vaddr);
 153                 host->sg_ptr = &host->bounce_sg;
 154                 sg = host->sg_ptr;
 155         }
 156
 157         ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_TO_DEVICE);
 158         if (ret > 0)
 159                 desc = chan->device->device_prep_slave_sg(chan, sg, ret,
 160                         DMA_TO_DEVICE, DMA_CTRL_ACK);
 161
 162         if (desc) {
 163                 cookie = dmaengine_submit(desc);
 164                 if (cookie < 0) {
 165                         desc = NULL;
 166                         ret = cookie;
 167                 }
 168         }
 169         dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n",
 170                 __func__, host->sg_len, ret, cookie, host->mrq);
 171
 172 pio:
 173         if (!desc) {
 174                 /* DMA failed, fall back to PIO */
 175                 if (ret >= 0)
 176                         ret = -EIO;
 177                 host->chan_tx = NULL;
 178                 dma_release_channel(chan);
 179                 /* Free the Rx channel too */
 180                 chan = host->chan_rx;
 181                 if (chan) {
 182                         host->chan_rx = NULL;
 183                         dma_release_channel(chan);
 184                 }
 185                 dev_warn(&host->pdev->dev,
 186                          "DMA failed: %d, falling back to PIO\n", ret);
 187                 tmio_mmc_enable_dma(host, false);
 188         }
 189
 190         dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d\n", __func__,
 191                 desc, cookie);
 192 }
 193
 194 void tmio_mmc_start_dma(struct tmio_mmc_host *host,
 195                                struct mmc_data *data)
 196 {
 197         if (data->flags & MMC_DATA_READ) {
 198                 if (host->chan_rx)
 199                         tmio_mmc_start_dma_rx(host);
 200         } else {
 201                 if (host->chan_tx)
 202                         tmio_mmc_start_dma_tx(host);
 203         }
 204 }
 205
 206 static void tmio_mmc_issue_tasklet_fn(unsigned long priv)
 207 {
 208         struct tmio_mmc_host *host = (struct tmio_mmc_host *)priv;
 209         struct dma_chan *chan = NULL;
 210
 211         spin_lock_irq(&host->lock);
 212
 213         if (host && host->data) {
 214                 if (host->data->flags & MMC_DATA_READ)
 215                         chan = host->chan_rx;
 216                 else
 217                         chan = host->chan_tx;
 218         }
 219
 220         spin_unlock_irq(&host->lock);
 221
 222         tmio_mmc_enable_mmc_irqs(host, TMIO_STAT_DATAEND);
 223
 224         if (chan)
 225                 dma_async_issue_pending(chan);
 226 }
 227
 228 static void tmio_mmc_tasklet_fn(unsigned long arg)
 229 {
 230         struct tmio_mmc_host *host = (struct tmio_mmc_host *)arg;
 231
 232         spin_lock_irq(&host->lock);
 233
 234         if (!host->data)
 235                 goto out;
 236
 237         if (host->data->flags & MMC_DATA_READ)
 238                 dma_unmap_sg(host->chan_rx->device->dev,
 239                              host->sg_ptr, host->sg_len,
 240                              DMA_FROM_DEVICE);
 241         else
 242                 dma_unmap_sg(host->chan_tx->device->dev,
 243                              host->sg_ptr, host->sg_len,
 244                              DMA_TO_DEVICE);
 245
 246         tmio_mmc_do_data_irq(host);
 247 out:
 248         spin_unlock_irq(&host->lock);
 249 }
 250
 251 /* It might be necessary to make filter MFD specific */
 252 static bool tmio_mmc_filter(struct dma_chan *chan, void *arg)
 253 {
 254         dev_dbg(chan->device->dev, "%s: slave data %p\n", __func__, arg);
 255         chan->private = arg;
 256         return true;
 257 }
 258
 259 void tmio_mmc_request_dma(struct tmio_mmc_host *host, struct tmio_mmc_data *pdata)
 260 {
 261         /* We can only either use DMA for both Tx and Rx or not use it at all */
 262         if (!pdata->dma)
 263                 return;
 264
 265         if (!host->chan_tx && !host->chan_rx) {
 266                 dma_cap_mask_t mask;
 267
 268                 dma_cap_zero(mask);
 269                 dma_cap_set(DMA_SLAVE, mask);
 270
 271                 host->chan_tx = dma_request_channel(mask, tmio_mmc_filter,
 272                                                     pdata->dma->chan_priv_tx);
 273                 dev_dbg(&host->pdev->dev, "%s: TX: got channel %p\n", __func__,
 274                         host->chan_tx);
 275
 276                 if (!host->chan_tx)
 277                         return;
 278
 279                 host->chan_rx = dma_request_channel(mask, tmio_mmc_filter,
 280                                                     pdata->dma->chan_priv_rx);
 281                 dev_dbg(&host->pdev->dev, "%s: RX: got channel %p\n", __func__,
 282                         host->chan_rx);
 283
 284                 if (!host->chan_rx)
 285                         goto ereqrx;
 286
 287                 host->bounce_buf = (u8 *)__get_free_page(GFP_KERNEL | GFP_DMA);
 288                 if (!host->bounce_buf)
 289                         goto ebouncebuf;
 290
 291                 tasklet_init(&host->dma_complete, tmio_mmc_tasklet_fn, (unsigned long)host);
 292                 tasklet_init(&host->dma_issue, tmio_mmc_issue_tasklet_fn, (unsigned long)host);
 293         }
 294
 295         tmio_mmc_enable_dma(host, true);
 296
 297         return;
 298
 299 ebouncebuf:
 300         dma_release_channel(host->chan_rx);
 301         host->chan_rx = NULL;
 302 ereqrx:
 303         dma_release_channel(host->chan_tx);
 304         host->chan_tx = NULL;
 305 }
 306
 307 void tmio_mmc_release_dma(struct tmio_mmc_host *host)
 308 {
 309         if (host->chan_tx) {
 310                 struct dma_chan *chan = host->chan_tx;
 311                 host->chan_tx = NULL;
 312                 dma_release_channel(chan);
 313         }
 314         if (host->chan_rx) {
 315                 struct dma_chan *chan = host->chan_rx;
 316                 host->chan_rx = NULL;
 317                 dma_release_channel(chan);
 318         }
 319         if (host->bounce_buf) {
 320                 free_pages((unsigned long)host->bounce_buf, 0);
 321                 host->bounce_buf = NULL;
 322         }
 323 }