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 (host->dma->enable)
  32                 host->dma->enable(host, enable);
  33 }
  34
  35 void tmio_mmc_abort_dma(struct tmio_mmc_host *host)
  36 {
  37         tmio_mmc_enable_dma(host, false);
  38
  39         if (host->chan_rx)
  40                 dmaengine_terminate_all(host->chan_rx);
  41         if (host->chan_tx)
  42                 dmaengine_terminate_all(host->chan_tx);
  43
  44         tmio_mmc_enable_dma(host, true);
  45 }
  46
  47 static void tmio_mmc_start_dma_rx(struct tmio_mmc_host *host)
  48 {
  49         struct scatterlist *sg = host->sg_ptr, *sg_tmp;
  50         struct dma_async_tx_descriptor *desc = NULL;
  51         struct dma_chan *chan = host->chan_rx;
  52         dma_cookie_t cookie;
  53         int ret, i;
  54         bool aligned = true, multiple = true;
  55         unsigned int align = (1 << host->pdata->alignment_shift) - 1;
  56
  57         for_each_sg(sg, sg_tmp, host->sg_len, i) {
  58                 if (sg_tmp->offset & align)
  59                         aligned = false;
  60                 if (sg_tmp->length & align) {
  61                         multiple = false;
  62                         break;
  63                 }
  64         }
  65
  66         if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_CACHE_SIZE ||
  67                           (align & PAGE_MASK))) || !multiple) {
  68                 ret = -EINVAL;
  69                 goto pio;
  70         }
  71
  72         if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
  73                 host->force_pio = true;
  74                 return;
  75         }
  76
  77         tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_RXRDY);
  78
  79         /* The only sg element can be unaligned, use our bounce buffer then */
  80         if (!aligned) {
  81                 sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
  82                 host->sg_ptr = &host->bounce_sg;
  83                 sg = host->sg_ptr;
  84         }
  85
  86         ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_FROM_DEVICE);
  87         if (ret > 0)
  88                 desc = dmaengine_prep_slave_sg(chan, sg, ret,
  89                         DMA_DEV_TO_MEM, DMA_CTRL_ACK);
  90
  91         if (desc) {
  92                 cookie = dmaengine_submit(desc);
  93                 if (cookie < 0) {
  94                         desc = NULL;
  95                         ret = cookie;
  96                 }
  97         }
  98 pio:
  99         if (!desc) {
 100                 /* DMA failed, fall back to PIO */
 101                 tmio_mmc_enable_dma(host, false);
 102                 if (ret >= 0)
 103                         ret = -EIO;
 104                 host->chan_rx = NULL;
 105                 dma_release_channel(chan);
 106                 /* Free the Tx channel too */
 107                 chan = host->chan_tx;
 108                 if (chan) {
 109                         host->chan_tx = NULL;
 110                         dma_release_channel(chan);
 111                 }
 112                 dev_warn(&host->pdev->dev,
 113                          "DMA failed: %d, falling back to PIO\n", ret);
 114         }
 115 }
 116
 117 static void tmio_mmc_start_dma_tx(struct tmio_mmc_host *host)
 118 {
 119         struct scatterlist *sg = host->sg_ptr, *sg_tmp;
 120         struct dma_async_tx_descriptor *desc = NULL;
 121         struct dma_chan *chan = host->chan_tx;
 122         dma_cookie_t cookie;
 123         int ret, i;
 124         bool aligned = true, multiple = true;
 125         unsigned int align = (1 << host->pdata->alignment_shift) - 1;
 126
 127         for_each_sg(sg, sg_tmp, host->sg_len, i) {
 128                 if (sg_tmp->offset & align)
 129                         aligned = false;
 130                 if (sg_tmp->length & align) {
 131                         multiple = false;
 132                         break;
 133                 }
 134         }
 135
 136         if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_CACHE_SIZE ||
 137                           (align & PAGE_MASK))) || !multiple) {
 138                 ret = -EINVAL;
 139                 goto pio;
 140         }
 141
 142         if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
 143                 host->force_pio = true;
 144                 return;
 145         }
 146
 147         tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_TXRQ);
 148
 149         /* The only sg element can be unaligned, use our bounce buffer then */
 150         if (!aligned) {
 151                 unsigned long flags;
 152                 void *sg_vaddr = tmio_mmc_kmap_atomic(sg, &flags);
 153                 sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
 154                 memcpy(host->bounce_buf, sg_vaddr, host->bounce_sg.length);
 155                 tmio_mmc_kunmap_atomic(sg, &flags, sg_vaddr);
 156                 host->sg_ptr = &host->bounce_sg;
 157                 sg = host->sg_ptr;
 158         }
 159
 160         ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_TO_DEVICE);
 161         if (ret > 0)
 162                 desc = dmaengine_prep_slave_sg(chan, sg, ret,
 163                         DMA_MEM_TO_DEV, DMA_CTRL_ACK);
 164
 165         if (desc) {
 166                 cookie = dmaengine_submit(desc);
 167                 if (cookie < 0) {
 168                         desc = NULL;
 169                         ret = cookie;
 170                 }
 171         }
 172 pio:
 173         if (!desc) {
 174                 /* DMA failed, fall back to PIO */
 175                 tmio_mmc_enable_dma(host, false);
 176                 if (ret >= 0)
 177                         ret = -EIO;
 178                 host->chan_tx = NULL;
 179                 dma_release_channel(chan);
 180                 /* Free the Rx channel too */
 181                 chan = host->chan_rx;
 182                 if (chan) {
 183                         host->chan_rx = NULL;
 184                         dma_release_channel(chan);
 185                 }
 186                 dev_warn(&host->pdev->dev,
 187                          "DMA failed: %d, falling back to PIO\n", ret);
 188         }
 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 void tmio_mmc_request_dma(struct tmio_mmc_host *host, struct tmio_mmc_data *pdata)
 249 {
 250         /* We can only either use DMA for both Tx and Rx or not use it at all */
 251         if (!host->dma || (!host->pdev->dev.of_node &&
 252                 (!pdata->chan_priv_tx || !pdata->chan_priv_rx)))
 253                 return;
 254
 255         if (!host->chan_tx && !host->chan_rx) {
 256                 struct resource *res = platform_get_resource(host->pdev,
 257                                                              IORESOURCE_MEM, 0);
 258                 struct dma_slave_config cfg = {};
 259                 dma_cap_mask_t mask;
 260                 int ret;
 261
 262                 if (!res)
 263                         return;
 264
 265                 dma_cap_zero(mask);
 266                 dma_cap_set(DMA_SLAVE, mask);
 267
 268                 host->chan_tx = dma_request_slave_channel_compat(mask,
 269                                         host->dma->filter, pdata->chan_priv_tx,
 270                                         &host->pdev->dev, "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                 cfg.direction = DMA_MEM_TO_DEV;
 278                 cfg.dst_addr = res->start + (CTL_SD_DATA_PORT << host->bus_shift);
 279                 cfg.dst_addr_width = host->dma->dma_buswidth;
 280                 if (!cfg.dst_addr_width)
 281                         cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 282                 cfg.src_addr = 0;
 283                 ret = dmaengine_slave_config(host->chan_tx, &cfg);
 284                 if (ret < 0)
 285                         goto ecfgtx;
 286
 287                 host->chan_rx = dma_request_slave_channel_compat(mask,
 288                                         host->dma->filter, pdata->chan_priv_rx,
 289                                         &host->pdev->dev, "rx");
 290                 dev_dbg(&host->pdev->dev, "%s: RX: got channel %p\n", __func__,
 291                         host->chan_rx);
 292
 293                 if (!host->chan_rx)
 294                         goto ereqrx;
 295
 296                 cfg.direction = DMA_DEV_TO_MEM;
 297                 cfg.src_addr = cfg.dst_addr + host->pdata->dma_rx_offset;
 298                 cfg.src_addr_width = host->dma->dma_buswidth;
 299                 if (!cfg.src_addr_width)
 300                         cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 301                 cfg.dst_addr = 0;
 302                 ret = dmaengine_slave_config(host->chan_rx, &cfg);
 303                 if (ret < 0)
 304                         goto ecfgrx;
 305
 306                 host->bounce_buf = (u8 *)__get_free_page(GFP_KERNEL | GFP_DMA);
 307                 if (!host->bounce_buf)
 308                         goto ebouncebuf;
 309
 310                 tasklet_init(&host->dma_complete, tmio_mmc_tasklet_fn, (unsigned long)host);
 311                 tasklet_init(&host->dma_issue, tmio_mmc_issue_tasklet_fn, (unsigned long)host);
 312         }
 313
 314         tmio_mmc_enable_dma(host, true);
 315
 316         return;
 317
 318 ebouncebuf:
 319 ecfgrx:
 320         dma_release_channel(host->chan_rx);
 321         host->chan_rx = NULL;
 322 ereqrx:
 323 ecfgtx:
 324         dma_release_channel(host->chan_tx);
 325         host->chan_tx = NULL;
 326 }
 327
 328 void tmio_mmc_release_dma(struct tmio_mmc_host *host)
 329 {
 330         if (host->chan_tx) {
 331                 struct dma_chan *chan = host->chan_tx;
 332                 host->chan_tx = NULL;
 333                 dma_release_channel(chan);
 334         }
 335         if (host->chan_rx) {
 336                 struct dma_chan *chan = host->chan_rx;
 337                 host->chan_rx = NULL;
 338                 dma_release_channel(chan);
 339         }
 340         if (host->bounce_buf) {
 341                 free_pages((unsigned long)host->bounce_buf, 0);
 342                 host->bounce_buf = NULL;
 343         }
 344 }