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/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 (host->dma->enable)
  31                 host->dma->enable(host, enable);
  32 }
  33
  34 void tmio_mmc_abort_dma(struct tmio_mmc_host *host)
  35 {
  36         tmio_mmc_enable_dma(host, false);
  37
  38         if (host->chan_rx)
  39                 dmaengine_terminate_all(host->chan_rx);
  40         if (host->chan_tx)
  41                 dmaengine_terminate_all(host->chan_tx);
  42
  43         tmio_mmc_enable_dma(host, true);
  44 }
  45
  46 static void tmio_mmc_start_dma_rx(struct tmio_mmc_host *host)
  47 {
  48         struct scatterlist *sg = host->sg_ptr, *sg_tmp;
  49         struct dma_async_tx_descriptor *desc = NULL;
  50         struct dma_chan *chan = host->chan_rx;
  51         dma_cookie_t cookie;
  52         int ret, i;
  53         bool aligned = true, multiple = true;
  54         unsigned int align = (1 << host->pdata->alignment_shift) - 1;
  55
  56         for_each_sg(sg, sg_tmp, host->sg_len, i) {
  57                 if (sg_tmp->offset & align)
  58                         aligned = false;
  59                 if (sg_tmp->length & align) {
  60                         multiple = false;
  61                         break;
  62                 }
  63         }
  64
  65         if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_SIZE ||
  66                           (align & PAGE_MASK))) || !multiple) {
  67                 ret = -EINVAL;
  68                 goto pio;
  69         }
  70
  71         if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
  72                 host->force_pio = true;
  73                 return;
  74         }
  75
  76         tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_RXRDY);
  77
  78         /* The only sg element can be unaligned, use our bounce buffer then */
  79         if (!aligned) {
  80                 sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
  81                 host->sg_ptr = &host->bounce_sg;
  82                 sg = host->sg_ptr;
  83         }
  84
  85         ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_FROM_DEVICE);
  86         if (ret > 0)
  87                 desc = dmaengine_prep_slave_sg(chan, sg, ret,
  88                         DMA_DEV_TO_MEM, DMA_CTRL_ACK);
  89
  90         if (desc) {
  91                 cookie = dmaengine_submit(desc);
  92                 if (cookie < 0) {
  93                         desc = NULL;
  94                         ret = cookie;
  95                 }
  96         }
  97 pio:
  98         if (!desc) {
  99                 /* DMA failed, fall back to PIO */
 100                 tmio_mmc_enable_dma(host, false);
 101                 if (ret >= 0)
 102                         ret = -EIO;
 103                 host->chan_rx = NULL;
 104                 dma_release_channel(chan);
 105                 /* Free the Tx channel too */
 106                 chan = host->chan_tx;
 107                 if (chan) {
 108                         host->chan_tx = NULL;
 109                         dma_release_channel(chan);
 110                 }
 111                 dev_warn(&host->pdev->dev,
 112                          "DMA failed: %d, falling back to PIO\n", ret);
 113         }
 114 }
 115
 116 static void tmio_mmc_start_dma_tx(struct tmio_mmc_host *host)
 117 {
 118         struct scatterlist *sg = host->sg_ptr, *sg_tmp;
 119         struct dma_async_tx_descriptor *desc = NULL;
 120         struct dma_chan *chan = host->chan_tx;
 121         dma_cookie_t cookie;
 122         int ret, i;
 123         bool aligned = true, multiple = true;
 124         unsigned int align = (1 << host->pdata->alignment_shift) - 1;
 125
 126         for_each_sg(sg, sg_tmp, host->sg_len, i) {
 127                 if (sg_tmp->offset & align)
 128                         aligned = false;
 129                 if (sg_tmp->length & align) {
 130                         multiple = false;
 131                         break;
 132                 }
 133         }
 134
 135         if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_SIZE ||
 136                           (align & PAGE_MASK))) || !multiple) {
 137                 ret = -EINVAL;
 138                 goto pio;
 139         }
 140
 141         if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
 142                 host->force_pio = true;
 143                 return;
 144         }
 145
 146         tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_TXRQ);
 147
 148         /* The only sg element can be unaligned, use our bounce buffer then */
 149         if (!aligned) {
 150                 unsigned long flags;
 151                 void *sg_vaddr = tmio_mmc_kmap_atomic(sg, &flags);
 152                 sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
 153                 memcpy(host->bounce_buf, sg_vaddr, host->bounce_sg.length);
 154                 tmio_mmc_kunmap_atomic(sg, &flags, sg_vaddr);
 155                 host->sg_ptr = &host->bounce_sg;
 156                 sg = host->sg_ptr;
 157         }
 158
 159         ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_TO_DEVICE);
 160         if (ret > 0)
 161                 desc = dmaengine_prep_slave_sg(chan, sg, ret,
 162                         DMA_MEM_TO_DEV, DMA_CTRL_ACK);
 163
 164         if (desc) {
 165                 cookie = dmaengine_submit(desc);
 166                 if (cookie < 0) {
 167                         desc = NULL;
 168                         ret = cookie;
 169                 }
 170         }
 171 pio:
 172         if (!desc) {
 173                 /* DMA failed, fall back to PIO */
 174                 tmio_mmc_enable_dma(host, false);
 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         }
 188 }
 189
 190 void tmio_mmc_start_dma(struct tmio_mmc_host *host,
 191                                struct mmc_data *data)
 192 {
 193         if (data->flags & MMC_DATA_READ) {
 194                 if (host->chan_rx)
 195                         tmio_mmc_start_dma_rx(host);
 196         } else {
 197                 if (host->chan_tx)
 198                         tmio_mmc_start_dma_tx(host);
 199         }
 200 }
 201
 202 static void tmio_mmc_issue_tasklet_fn(unsigned long priv)
 203 {
 204         struct tmio_mmc_host *host = (struct tmio_mmc_host *)priv;
 205         struct dma_chan *chan = NULL;
 206
 207         spin_lock_irq(&host->lock);
 208
 209         if (host && host->data) {
 210                 if (host->data->flags & MMC_DATA_READ)
 211                         chan = host->chan_rx;
 212                 else
 213                         chan = host->chan_tx;
 214         }
 215
 216         spin_unlock_irq(&host->lock);
 217
 218         tmio_mmc_enable_mmc_irqs(host, TMIO_STAT_DATAEND);
 219
 220         if (chan)
 221                 dma_async_issue_pending(chan);
 222 }
 223
 224 static void tmio_mmc_tasklet_fn(unsigned long arg)
 225 {
 226         struct tmio_mmc_host *host = (struct tmio_mmc_host *)arg;
 227
 228         spin_lock_irq(&host->lock);
 229
 230         if (!host->data)
 231                 goto out;
 232
 233         if (host->data->flags & MMC_DATA_READ)
 234                 dma_unmap_sg(host->chan_rx->device->dev,
 235                              host->sg_ptr, host->sg_len,
 236                              DMA_FROM_DEVICE);
 237         else
 238                 dma_unmap_sg(host->chan_tx->device->dev,
 239                              host->sg_ptr, host->sg_len,
 240                              DMA_TO_DEVICE);
 241
 242         tmio_mmc_do_data_irq(host);
 243 out:
 244         spin_unlock_irq(&host->lock);
 245 }
 246
 247 void tmio_mmc_request_dma(struct tmio_mmc_host *host, struct tmio_mmc_data *pdata)
 248 {
 249         /* We can only either use DMA for both Tx and Rx or not use it at all */
 250         if (!host->dma || (!host->pdev->dev.of_node &&
 251                 (!pdata->chan_priv_tx || !pdata->chan_priv_rx)))
 252                 return;
 253
 254         if (!host->chan_tx && !host->chan_rx) {
 255                 struct resource *res = platform_get_resource(host->pdev,
 256                                                              IORESOURCE_MEM, 0);
 257                 struct dma_slave_config cfg = {};
 258                 dma_cap_mask_t mask;
 259                 int ret;
 260
 261                 if (!res)
 262                         return;
 263
 264                 dma_cap_zero(mask);
 265                 dma_cap_set(DMA_SLAVE, mask);
 266
 267                 host->chan_tx = dma_request_slave_channel_compat(mask,
 268                                         host->dma->filter, pdata->chan_priv_tx,
 269                                         &host->pdev->dev, "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                 cfg.direction = DMA_MEM_TO_DEV;
 277                 cfg.dst_addr = res->start + (CTL_SD_DATA_PORT << host->bus_shift);
 278                 cfg.dst_addr_width = host->dma->dma_buswidth;
 279                 if (!cfg.dst_addr_width)
 280                         cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 281                 cfg.src_addr = 0;
 282                 ret = dmaengine_slave_config(host->chan_tx, &cfg);
 283                 if (ret < 0)
 284                         goto ecfgtx;
 285
 286                 host->chan_rx = dma_request_slave_channel_compat(mask,
 287                                         host->dma->filter, pdata->chan_priv_rx,
 288                                         &host->pdev->dev, "rx");
 289                 dev_dbg(&host->pdev->dev, "%s: RX: got channel %p\n", __func__,
 290                         host->chan_rx);
 291
 292                 if (!host->chan_rx)
 293                         goto ereqrx;
 294
 295                 cfg.direction = DMA_DEV_TO_MEM;
 296                 cfg.src_addr = cfg.dst_addr + host->pdata->dma_rx_offset;
 297                 cfg.src_addr_width = host->dma->dma_buswidth;
 298                 if (!cfg.src_addr_width)
 299                         cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 300                 cfg.dst_addr = 0;
 301                 ret = dmaengine_slave_config(host->chan_rx, &cfg);
 302                 if (ret < 0)
 303                         goto ecfgrx;
 304
 305                 host->bounce_buf = (u8 *)__get_free_page(GFP_KERNEL | GFP_DMA);
 306                 if (!host->bounce_buf)
 307                         goto ebouncebuf;
 308
 309                 tasklet_init(&host->dma_complete, tmio_mmc_tasklet_fn, (unsigned long)host);
 310                 tasklet_init(&host->dma_issue, tmio_mmc_issue_tasklet_fn, (unsigned long)host);
 311         }
 312
 313         tmio_mmc_enable_dma(host, true);
 314
 315         return;
 316
 317 ebouncebuf:
 318 ecfgrx:
 319         dma_release_channel(host->chan_rx);
 320         host->chan_rx = NULL;
 321 ereqrx:
 322 ecfgtx:
 323         dma_release_channel(host->chan_tx);
 324         host->chan_tx = NULL;
 325 }
 326
 327 void tmio_mmc_release_dma(struct tmio_mmc_host *host)
 328 {
 329         if (host->chan_tx) {
 330                 struct dma_chan *chan = host->chan_tx;
 331                 host->chan_tx = NULL;
 332                 dma_release_channel(chan);
 333         }
 334         if (host->chan_rx) {
 335                 struct dma_chan *chan = host->chan_rx;
 336                 host->chan_rx = NULL;
 337                 dma_release_channel(chan);
 338         }
 339         if (host->bounce_buf) {
 340                 free_pages((unsigned long)host->bounce_buf, 0);
 341                 host->bounce_buf = NULL;
 342         }
 343 }