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_dma_callback(void *arg)
  47 {
  48         struct tmio_mmc_host *host = arg;
  49
  50         wait_for_completion(&host->dma_dataend);
  51
  52         spin_lock_irq(&host->lock);
  53
  54         if (!host->data)
  55                 goto out;
  56
  57         if (host->data->flags & MMC_DATA_READ)
  58                 dma_unmap_sg(host->chan_rx->device->dev,
  59                              host->sg_ptr, host->sg_len,
  60                              DMA_FROM_DEVICE);
  61         else
  62                 dma_unmap_sg(host->chan_tx->device->dev,
  63                              host->sg_ptr, host->sg_len,
  64                              DMA_TO_DEVICE);
  65
  66         tmio_mmc_do_data_irq(host);
  67 out:
  68         spin_unlock_irq(&host->lock);
  69 }
  70
  71 static void tmio_mmc_start_dma_rx(struct tmio_mmc_host *host)
  72 {
  73         struct scatterlist *sg = host->sg_ptr, *sg_tmp;
  74         struct dma_async_tx_descriptor *desc = NULL;
  75         struct dma_chan *chan = host->chan_rx;
  76         dma_cookie_t cookie;
  77         int ret, i;
  78         bool aligned = true, multiple = true;
  79         unsigned int align = (1 << host->pdata->alignment_shift) - 1;
  80
  81         for_each_sg(sg, sg_tmp, host->sg_len, i) {
  82                 if (sg_tmp->offset & align)
  83                         aligned = false;
  84                 if (sg_tmp->length & align) {
  85                         multiple = false;
  86                         break;
  87                 }
  88         }
  89
  90         if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_SIZE ||
  91                           (align & PAGE_MASK))) || !multiple) {
  92                 ret = -EINVAL;
  93                 goto pio;
  94         }
  95
  96         if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
  97                 host->force_pio = true;
  98                 return;
  99         }
 100
 101         tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_RXRDY);
 102
 103         /* The only sg element can be unaligned, use our bounce buffer then */
 104         if (!aligned) {
 105                 sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
 106                 host->sg_ptr = &host->bounce_sg;
 107                 sg = host->sg_ptr;
 108         }
 109
 110         ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_FROM_DEVICE);
 111         if (ret > 0)
 112                 desc = dmaengine_prep_slave_sg(chan, sg, ret,
 113                         DMA_DEV_TO_MEM, DMA_CTRL_ACK);
 114
 115         if (desc) {
 116                 reinit_completion(&host->dma_dataend);
 117                 desc->callback = tmio_mmc_dma_callback;
 118                 desc->callback_param = host;
 119
 120                 cookie = dmaengine_submit(desc);
 121                 if (cookie < 0) {
 122                         desc = NULL;
 123                         ret = cookie;
 124                 }
 125         }
 126 pio:
 127         if (!desc) {
 128                 /* DMA failed, fall back to PIO */
 129                 tmio_mmc_enable_dma(host, false);
 130                 if (ret >= 0)
 131                         ret = -EIO;
 132                 host->chan_rx = NULL;
 133                 dma_release_channel(chan);
 134                 /* Free the Tx channel too */
 135                 chan = host->chan_tx;
 136                 if (chan) {
 137                         host->chan_tx = NULL;
 138                         dma_release_channel(chan);
 139                 }
 140                 dev_warn(&host->pdev->dev,
 141                          "DMA failed: %d, falling back to PIO\n", ret);
 142         }
 143 }
 144
 145 static void tmio_mmc_start_dma_tx(struct tmio_mmc_host *host)
 146 {
 147         struct scatterlist *sg = host->sg_ptr, *sg_tmp;
 148         struct dma_async_tx_descriptor *desc = NULL;
 149         struct dma_chan *chan = host->chan_tx;
 150         dma_cookie_t cookie;
 151         int ret, i;
 152         bool aligned = true, multiple = true;
 153         unsigned int align = (1 << host->pdata->alignment_shift) - 1;
 154
 155         for_each_sg(sg, sg_tmp, host->sg_len, i) {
 156                 if (sg_tmp->offset & align)
 157                         aligned = false;
 158                 if (sg_tmp->length & align) {
 159                         multiple = false;
 160                         break;
 161                 }
 162         }
 163
 164         if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_SIZE ||
 165                           (align & PAGE_MASK))) || !multiple) {
 166                 ret = -EINVAL;
 167                 goto pio;
 168         }
 169
 170         if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
 171                 host->force_pio = true;
 172                 return;
 173         }
 174
 175         tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_TXRQ);
 176
 177         /* The only sg element can be unaligned, use our bounce buffer then */
 178         if (!aligned) {
 179                 unsigned long flags;
 180                 void *sg_vaddr = tmio_mmc_kmap_atomic(sg, &flags);
 181                 sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
 182                 memcpy(host->bounce_buf, sg_vaddr, host->bounce_sg.length);
 183                 tmio_mmc_kunmap_atomic(sg, &flags, sg_vaddr);
 184                 host->sg_ptr = &host->bounce_sg;
 185                 sg = host->sg_ptr;
 186         }
 187
 188         ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_TO_DEVICE);
 189         if (ret > 0)
 190                 desc = dmaengine_prep_slave_sg(chan, sg, ret,
 191                         DMA_MEM_TO_DEV, DMA_CTRL_ACK);
 192
 193         if (desc) {
 194                 reinit_completion(&host->dma_dataend);
 195                 desc->callback = tmio_mmc_dma_callback;
 196                 desc->callback_param = host;
 197
 198                 cookie = dmaengine_submit(desc);
 199                 if (cookie < 0) {
 200                         desc = NULL;
 201                         ret = cookie;
 202                 }
 203         }
 204 pio:
 205         if (!desc) {
 206                 /* DMA failed, fall back to PIO */
 207                 tmio_mmc_enable_dma(host, false);
 208                 if (ret >= 0)
 209                         ret = -EIO;
 210                 host->chan_tx = NULL;
 211                 dma_release_channel(chan);
 212                 /* Free the Rx channel too */
 213                 chan = host->chan_rx;
 214                 if (chan) {
 215                         host->chan_rx = NULL;
 216                         dma_release_channel(chan);
 217                 }
 218                 dev_warn(&host->pdev->dev,
 219                          "DMA failed: %d, falling back to PIO\n", ret);
 220         }
 221 }
 222
 223 void tmio_mmc_start_dma(struct tmio_mmc_host *host,
 224                                struct mmc_data *data)
 225 {
 226         if (data->flags & MMC_DATA_READ) {
 227                 if (host->chan_rx)
 228                         tmio_mmc_start_dma_rx(host);
 229         } else {
 230                 if (host->chan_tx)
 231                         tmio_mmc_start_dma_tx(host);
 232         }
 233 }
 234
 235 static void tmio_mmc_issue_tasklet_fn(unsigned long priv)
 236 {
 237         struct tmio_mmc_host *host = (struct tmio_mmc_host *)priv;
 238         struct dma_chan *chan = NULL;
 239
 240         spin_lock_irq(&host->lock);
 241
 242         if (host && host->data) {
 243                 if (host->data->flags & MMC_DATA_READ)
 244                         chan = host->chan_rx;
 245                 else
 246                         chan = host->chan_tx;
 247         }
 248
 249         spin_unlock_irq(&host->lock);
 250
 251         tmio_mmc_enable_mmc_irqs(host, TMIO_STAT_DATAEND);
 252
 253         if (chan)
 254                 dma_async_issue_pending(chan);
 255 }
 256
 257 void tmio_mmc_request_dma(struct tmio_mmc_host *host, struct tmio_mmc_data *pdata)
 258 {
 259         /* We can only either use DMA for both Tx and Rx or not use it at all */
 260         if (!host->dma || (!host->pdev->dev.of_node &&
 261                 (!pdata->chan_priv_tx || !pdata->chan_priv_rx)))
 262                 return;
 263
 264         if (!host->chan_tx && !host->chan_rx) {
 265                 struct resource *res = platform_get_resource(host->pdev,
 266                                                              IORESOURCE_MEM, 0);
 267                 struct dma_slave_config cfg = {};
 268                 dma_cap_mask_t mask;
 269                 int ret;
 270
 271                 if (!res)
 272                         return;
 273
 274                 dma_cap_zero(mask);
 275                 dma_cap_set(DMA_SLAVE, mask);
 276
 277                 host->chan_tx = dma_request_slave_channel_compat(mask,
 278                                         host->dma->filter, pdata->chan_priv_tx,
 279                                         &host->pdev->dev, "tx");
 280                 dev_dbg(&host->pdev->dev, "%s: TX: got channel %p\n", __func__,
 281                         host->chan_tx);
 282
 283                 if (!host->chan_tx)
 284                         return;
 285
 286                 cfg.direction = DMA_MEM_TO_DEV;
 287                 cfg.dst_addr = res->start + (CTL_SD_DATA_PORT << host->bus_shift);
 288                 cfg.dst_addr_width = host->dma->dma_buswidth;
 289                 if (!cfg.dst_addr_width)
 290                         cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 291                 cfg.src_addr = 0;
 292                 ret = dmaengine_slave_config(host->chan_tx, &cfg);
 293                 if (ret < 0)
 294                         goto ecfgtx;
 295
 296                 host->chan_rx = dma_request_slave_channel_compat(mask,
 297                                         host->dma->filter, pdata->chan_priv_rx,
 298                                         &host->pdev->dev, "rx");
 299                 dev_dbg(&host->pdev->dev, "%s: RX: got channel %p\n", __func__,
 300                         host->chan_rx);
 301
 302                 if (!host->chan_rx)
 303                         goto ereqrx;
 304
 305                 cfg.direction = DMA_DEV_TO_MEM;
 306                 cfg.src_addr = cfg.dst_addr + host->pdata->dma_rx_offset;
 307                 cfg.src_addr_width = host->dma->dma_buswidth;
 308                 if (!cfg.src_addr_width)
 309                         cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 310                 cfg.dst_addr = 0;
 311                 ret = dmaengine_slave_config(host->chan_rx, &cfg);
 312                 if (ret < 0)
 313                         goto ecfgrx;
 314
 315                 host->bounce_buf = (u8 *)__get_free_page(GFP_KERNEL | GFP_DMA);
 316                 if (!host->bounce_buf)
 317                         goto ebouncebuf;
 318
 319                 init_completion(&host->dma_dataend);
 320                 tasklet_init(&host->dma_issue, tmio_mmc_issue_tasklet_fn, (unsigned long)host);
 321         }
 322
 323         tmio_mmc_enable_dma(host, true);
 324
 325         return;
 326
 327 ebouncebuf:
 328 ecfgrx:
 329         dma_release_channel(host->chan_rx);
 330         host->chan_rx = NULL;
 331 ereqrx:
 332 ecfgtx:
 333         dma_release_channel(host->chan_tx);
 334         host->chan_tx = NULL;
 335 }
 336
 337 void tmio_mmc_release_dma(struct tmio_mmc_host *host)
 338 {
 339         if (host->chan_tx) {
 340                 struct dma_chan *chan = host->chan_tx;
 341                 host->chan_tx = NULL;
 342                 dma_release_channel(chan);
 343         }
 344         if (host->chan_rx) {
 345                 struct dma_chan *chan = host->chan_rx;
 346                 host->chan_rx = NULL;
 347                 dma_release_channel(chan);
 348         }
 349         if (host->bounce_buf) {
 350                 free_pages((unsigned long)host->bounce_buf, 0);
 351                 host->bounce_buf = NULL;
 352         }
 353 }