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->pdata->flags & TMIO_MMC_HAVE_CTL_DMA_REG)
  32                 sd_ctrl_write16(host, CTL_DMA_ENABLE, enable ? 2 : 0);
  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         struct tmio_mmc_data *pdata = host->pdata;
  53         dma_cookie_t cookie;
  54         int ret, i;
  55         bool aligned = true, multiple = true;
  56         unsigned int align = (1 << pdata->dma->alignment_shift) - 1;
  57
  58         for_each_sg(sg, sg_tmp, host->sg_len, i) {
  59                 if (sg_tmp->offset & align)
  60                         aligned = false;
  61                 if (sg_tmp->length & align) {
  62                         multiple = false;
  63                         break;
  64                 }
  65         }
  66
  67         if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_CACHE_SIZE ||
  68                           (align & PAGE_MASK))) || !multiple) {
  69                 ret = -EINVAL;
  70                 goto pio;
  71         }
  72
  73         if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
  74                 host->force_pio = true;
  75                 return;
  76         }
  77
  78         tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_RXRDY);
  79
  80         /* The only sg element can be unaligned, use our bounce buffer then */
  81         if (!aligned) {
  82                 sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
  83                 host->sg_ptr = &host->bounce_sg;
  84                 sg = host->sg_ptr;
  85         }
  86
  87         ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_FROM_DEVICE);
  88         if (ret > 0)
  89                 desc = dmaengine_prep_slave_sg(chan, sg, ret,
  90                         DMA_DEV_TO_MEM, DMA_CTRL_ACK);
  91
  92         if (desc) {
  93                 cookie = dmaengine_submit(desc);
  94                 if (cookie < 0) {
  95                         desc = NULL;
  96                         ret = cookie;
  97                 }
  98         }
  99         dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n",
 100                 __func__, host->sg_len, ret, cookie, host->mrq);
 101
 102 pio:
 103         if (!desc) {
 104                 /* DMA failed, fall back to PIO */
 105                 tmio_mmc_enable_dma(host, false);
 106                 if (ret >= 0)
 107                         ret = -EIO;
 108                 host->chan_rx = NULL;
 109                 dma_release_channel(chan);
 110                 /* Free the Tx channel too */
 111                 chan = host->chan_tx;
 112                 if (chan) {
 113                         host->chan_tx = NULL;
 114                         dma_release_channel(chan);
 115                 }
 116                 dev_warn(&host->pdev->dev,
 117                          "DMA failed: %d, falling back to PIO\n", ret);
 118         }
 119
 120         dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d, sg[%d]\n", __func__,
 121                 desc, cookie, host->sg_len);
 122 }
 123
 124 static void tmio_mmc_start_dma_tx(struct tmio_mmc_host *host)
 125 {
 126         struct scatterlist *sg = host->sg_ptr, *sg_tmp;
 127         struct dma_async_tx_descriptor *desc = NULL;
 128         struct dma_chan *chan = host->chan_tx;
 129         struct tmio_mmc_data *pdata = host->pdata;
 130         dma_cookie_t cookie;
 131         int ret, i;
 132         bool aligned = true, multiple = true;
 133         unsigned int align = (1 << pdata->dma->alignment_shift) - 1;
 134
 135         for_each_sg(sg, sg_tmp, host->sg_len, i) {
 136                 if (sg_tmp->offset & align)
 137                         aligned = false;
 138                 if (sg_tmp->length & align) {
 139                         multiple = false;
 140                         break;
 141                 }
 142         }
 143
 144         if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_CACHE_SIZE ||
 145                           (align & PAGE_MASK))) || !multiple) {
 146                 ret = -EINVAL;
 147                 goto pio;
 148         }
 149
 150         if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
 151                 host->force_pio = true;
 152                 return;
 153         }
 154
 155         tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_TXRQ);
 156
 157         /* The only sg element can be unaligned, use our bounce buffer then */
 158         if (!aligned) {
 159                 unsigned long flags;
 160                 void *sg_vaddr = tmio_mmc_kmap_atomic(sg, &flags);
 161                 sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
 162                 memcpy(host->bounce_buf, sg_vaddr, host->bounce_sg.length);
 163                 tmio_mmc_kunmap_atomic(sg, &flags, sg_vaddr);
 164                 host->sg_ptr = &host->bounce_sg;
 165                 sg = host->sg_ptr;
 166         }
 167
 168         ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_TO_DEVICE);
 169         if (ret > 0)
 170                 desc = dmaengine_prep_slave_sg(chan, sg, ret,
 171                         DMA_MEM_TO_DEV, DMA_CTRL_ACK);
 172
 173         if (desc) {
 174                 cookie = dmaengine_submit(desc);
 175                 if (cookie < 0) {
 176                         desc = NULL;
 177                         ret = cookie;
 178                 }
 179         }
 180         dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n",
 181                 __func__, host->sg_len, ret, cookie, host->mrq);
 182
 183 pio:
 184         if (!desc) {
 185                 /* DMA failed, fall back to PIO */
 186                 tmio_mmc_enable_dma(host, false);
 187                 if (ret >= 0)
 188                         ret = -EIO;
 189                 host->chan_tx = NULL;
 190                 dma_release_channel(chan);
 191                 /* Free the Rx channel too */
 192                 chan = host->chan_rx;
 193                 if (chan) {
 194                         host->chan_rx = NULL;
 195                         dma_release_channel(chan);
 196                 }
 197                 dev_warn(&host->pdev->dev,
 198                          "DMA failed: %d, falling back to PIO\n", ret);
 199         }
 200
 201         dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d\n", __func__,
 202                 desc, cookie);
 203 }
 204
 205 void tmio_mmc_start_dma(struct tmio_mmc_host *host,
 206                                struct mmc_data *data)
 207 {
 208         if (data->flags & MMC_DATA_READ) {
 209                 if (host->chan_rx)
 210                         tmio_mmc_start_dma_rx(host);
 211         } else {
 212                 if (host->chan_tx)
 213                         tmio_mmc_start_dma_tx(host);
 214         }
 215 }
 216
 217 static void tmio_mmc_issue_tasklet_fn(unsigned long priv)
 218 {
 219         struct tmio_mmc_host *host = (struct tmio_mmc_host *)priv;
 220         struct dma_chan *chan = NULL;
 221
 222         spin_lock_irq(&host->lock);
 223
 224         if (host && host->data) {
 225                 if (host->data->flags & MMC_DATA_READ)
 226                         chan = host->chan_rx;
 227                 else
 228                         chan = host->chan_tx;
 229         }
 230
 231         spin_unlock_irq(&host->lock);
 232
 233         tmio_mmc_enable_mmc_irqs(host, TMIO_STAT_DATAEND);
 234
 235         if (chan)
 236                 dma_async_issue_pending(chan);
 237 }
 238
 239 static void tmio_mmc_tasklet_fn(unsigned long arg)
 240 {
 241         struct tmio_mmc_host *host = (struct tmio_mmc_host *)arg;
 242
 243         spin_lock_irq(&host->lock);
 244
 245         if (!host->data)
 246                 goto out;
 247
 248         if (host->data->flags & MMC_DATA_READ)
 249                 dma_unmap_sg(host->chan_rx->device->dev,
 250                              host->sg_ptr, host->sg_len,
 251                              DMA_FROM_DEVICE);
 252         else
 253                 dma_unmap_sg(host->chan_tx->device->dev,
 254                              host->sg_ptr, host->sg_len,
 255                              DMA_TO_DEVICE);
 256
 257         tmio_mmc_do_data_irq(host);
 258 out:
 259         spin_unlock_irq(&host->lock);
 260 }
 261
 262 void tmio_mmc_request_dma(struct tmio_mmc_host *host, struct tmio_mmc_data *pdata)
 263 {
 264         /* We can only either use DMA for both Tx and Rx or not use it at all */
 265         if (!pdata->dma || (!host->pdev->dev.of_node &&
 266                 (!pdata->dma->chan_priv_tx || !pdata->dma->chan_priv_rx)))
 267                 return;
 268
 269         if (!host->chan_tx && !host->chan_rx) {
 270                 struct resource *res = platform_get_resource(host->pdev,
 271                                                              IORESOURCE_MEM, 0);
 272                 struct dma_slave_config cfg = {};
 273                 dma_cap_mask_t mask;
 274                 int ret;
 275
 276                 if (!res)
 277                         return;
 278
 279                 dma_cap_zero(mask);
 280                 dma_cap_set(DMA_SLAVE, mask);
 281
 282                 host->chan_tx = dma_request_slave_channel_compat(mask,
 283                                         pdata->dma->filter, pdata->dma->chan_priv_tx,
 284                                         &host->pdev->dev, "tx");
 285                 dev_dbg(&host->pdev->dev, "%s: TX: got channel %p\n", __func__,
 286                         host->chan_tx);
 287
 288                 if (!host->chan_tx)
 289                         return;
 290
 291                 if (pdata->dma->chan_priv_tx)
 292                         cfg.slave_id = pdata->dma->slave_id_tx;
 293                 cfg.direction = DMA_MEM_TO_DEV;
 294                 cfg.dst_addr = res->start + (CTL_SD_DATA_PORT << host->pdata->bus_shift);
 295                 cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 296                 cfg.src_addr = 0;
 297                 ret = dmaengine_slave_config(host->chan_tx, &cfg);
 298                 if (ret < 0)
 299                         goto ecfgtx;
 300
 301                 host->chan_rx = dma_request_slave_channel_compat(mask,
 302                                         pdata->dma->filter, pdata->dma->chan_priv_rx,
 303                                         &host->pdev->dev, "rx");
 304                 dev_dbg(&host->pdev->dev, "%s: RX: got channel %p\n", __func__,
 305                         host->chan_rx);
 306
 307                 if (!host->chan_rx)
 308                         goto ereqrx;
 309
 310                 if (pdata->dma->chan_priv_rx)
 311                         cfg.slave_id = pdata->dma->slave_id_rx;
 312                 cfg.direction = DMA_DEV_TO_MEM;
 313                 cfg.src_addr = cfg.dst_addr + pdata->dma->dma_rx_offset;
 314                 cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 315                 cfg.dst_addr = 0;
 316                 ret = dmaengine_slave_config(host->chan_rx, &cfg);
 317                 if (ret < 0)
 318                         goto ecfgrx;
 319
 320                 host->bounce_buf = (u8 *)__get_free_page(GFP_KERNEL | GFP_DMA);
 321                 if (!host->bounce_buf)
 322                         goto ebouncebuf;
 323
 324                 tasklet_init(&host->dma_complete, tmio_mmc_tasklet_fn, (unsigned long)host);
 325                 tasklet_init(&host->dma_issue, tmio_mmc_issue_tasklet_fn, (unsigned long)host);
 326         }
 327
 328         tmio_mmc_enable_dma(host, true);
 329
 330         return;
 331
 332 ebouncebuf:
 333 ecfgrx:
 334         dma_release_channel(host->chan_rx);
 335         host->chan_rx = NULL;
 336 ereqrx:
 337 ecfgtx:
 338         dma_release_channel(host->chan_tx);
 339         host->chan_tx = NULL;
 340 }
 341
 342 void tmio_mmc_release_dma(struct tmio_mmc_host *host)
 343 {
 344         if (host->chan_tx) {
 345                 struct dma_chan *chan = host->chan_tx;
 346                 host->chan_tx = NULL;
 347                 dma_release_channel(chan);
 348         }
 349         if (host->chan_rx) {
 350                 struct dma_chan *chan = host->chan_rx;
 351                 host->chan_rx = NULL;
 352                 dma_release_channel(chan);
 353         }
 354         if (host->bounce_buf) {
 355                 free_pages((unsigned long)host->bounce_buf, 0);
 356                 host->bounce_buf = NULL;
 357         }
 358 }