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         spin_lock_irq(&host->lock);
  51
  52         if (!host->data)
  53                 goto out;
  54
  55         if (host->data->flags & MMC_DATA_READ)
  56                 dma_unmap_sg(host->chan_rx->device->dev,
  57                              host->sg_ptr, host->sg_len,
  58                              DMA_FROM_DEVICE);
  59         else
  60                 dma_unmap_sg(host->chan_tx->device->dev,
  61                              host->sg_ptr, host->sg_len,
  62                              DMA_TO_DEVICE);
  63
  64         spin_unlock_irq(&host->lock);
  65
  66         wait_for_completion(&host->dma_dataend);
  67
  68         spin_lock_irq(&host->lock);
  69         tmio_mmc_do_data_irq(host);
  70 out:
  71         spin_unlock_irq(&host->lock);
  72 }
  73
  74 static void tmio_mmc_start_dma_rx(struct tmio_mmc_host *host)
  75 {
  76         struct scatterlist *sg = host->sg_ptr, *sg_tmp;
  77         struct dma_async_tx_descriptor *desc = NULL;
  78         struct dma_chan *chan = host->chan_rx;
  79         dma_cookie_t cookie;
  80         int ret, i;
  81         bool aligned = true, multiple = true;
  82         unsigned int align = (1 << host->pdata->alignment_shift) - 1;
  83
  84         for_each_sg(sg, sg_tmp, host->sg_len, i) {
  85                 if (sg_tmp->offset & align)
  86                         aligned = false;
  87                 if (sg_tmp->length & align) {
  88                         multiple = false;
  89                         break;
  90                 }
  91         }
  92
  93         if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_SIZE ||
  94                           (align & PAGE_MASK))) || !multiple) {
  95                 ret = -EINVAL;
  96                 goto pio;
  97         }
  98
  99         if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
 100                 host->force_pio = true;
 101                 return;
 102         }
 103
 104         tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_RXRDY);
 105
 106         /* The only sg element can be unaligned, use our bounce buffer then */
 107         if (!aligned) {
 108                 sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
 109                 host->sg_ptr = &host->bounce_sg;
 110                 sg = host->sg_ptr;
 111         }
 112
 113         ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_FROM_DEVICE);
 114         if (ret > 0)
 115                 desc = dmaengine_prep_slave_sg(chan, sg, ret,
 116                         DMA_DEV_TO_MEM, DMA_CTRL_ACK);
 117
 118         if (desc) {
 119                 reinit_completion(&host->dma_dataend);
 120                 desc->callback = tmio_mmc_dma_callback;
 121                 desc->callback_param = host;
 122
 123                 cookie = dmaengine_submit(desc);
 124                 if (cookie < 0) {
 125                         desc = NULL;
 126                         ret = cookie;
 127                 }
 128         }
 129 pio:
 130         if (!desc) {
 131                 /* DMA failed, fall back to PIO */
 132                 tmio_mmc_enable_dma(host, false);
 133                 if (ret >= 0)
 134                         ret = -EIO;
 135                 host->chan_rx = NULL;
 136                 dma_release_channel(chan);
 137                 /* Free the Tx channel too */
 138                 chan = host->chan_tx;
 139                 if (chan) {
 140                         host->chan_tx = NULL;
 141                         dma_release_channel(chan);
 142                 }
 143                 dev_warn(&host->pdev->dev,
 144                          "DMA failed: %d, falling back to PIO\n", ret);
 145         }
 146 }
 147
 148 static void tmio_mmc_start_dma_tx(struct tmio_mmc_host *host)
 149 {
 150         struct scatterlist *sg = host->sg_ptr, *sg_tmp;
 151         struct dma_async_tx_descriptor *desc = NULL;
 152         struct dma_chan *chan = host->chan_tx;
 153         dma_cookie_t cookie;
 154         int ret, i;
 155         bool aligned = true, multiple = true;
 156         unsigned int align = (1 << host->pdata->alignment_shift) - 1;
 157
 158         for_each_sg(sg, sg_tmp, host->sg_len, i) {
 159                 if (sg_tmp->offset & align)
 160                         aligned = false;
 161                 if (sg_tmp->length & align) {
 162                         multiple = false;
 163                         break;
 164                 }
 165         }
 166
 167         if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_SIZE ||
 168                           (align & PAGE_MASK))) || !multiple) {
 169                 ret = -EINVAL;
 170                 goto pio;
 171         }
 172
 173         if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
 174                 host->force_pio = true;
 175                 return;
 176         }
 177
 178         tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_TXRQ);
 179
 180         /* The only sg element can be unaligned, use our bounce buffer then */
 181         if (!aligned) {
 182                 unsigned long flags;
 183                 void *sg_vaddr = tmio_mmc_kmap_atomic(sg, &flags);
 184                 sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
 185                 memcpy(host->bounce_buf, sg_vaddr, host->bounce_sg.length);
 186                 tmio_mmc_kunmap_atomic(sg, &flags, sg_vaddr);
 187                 host->sg_ptr = &host->bounce_sg;
 188                 sg = host->sg_ptr;
 189         }
 190
 191         ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_TO_DEVICE);
 192         if (ret > 0)
 193                 desc = dmaengine_prep_slave_sg(chan, sg, ret,
 194                         DMA_MEM_TO_DEV, DMA_CTRL_ACK);
 195
 196         if (desc) {
 197                 reinit_completion(&host->dma_dataend);
 198                 desc->callback = tmio_mmc_dma_callback;
 199                 desc->callback_param = host;
 200
 201                 cookie = dmaengine_submit(desc);
 202                 if (cookie < 0) {
 203                         desc = NULL;
 204                         ret = cookie;
 205                 }
 206         }
 207 pio:
 208         if (!desc) {
 209                 /* DMA failed, fall back to PIO */
 210                 tmio_mmc_enable_dma(host, false);
 211                 if (ret >= 0)
 212                         ret = -EIO;
 213                 host->chan_tx = NULL;
 214                 dma_release_channel(chan);
 215                 /* Free the Rx channel too */
 216                 chan = host->chan_rx;
 217                 if (chan) {
 218                         host->chan_rx = NULL;
 219                         dma_release_channel(chan);
 220                 }
 221                 dev_warn(&host->pdev->dev,
 222                          "DMA failed: %d, falling back to PIO\n", ret);
 223         }
 224 }
 225
 226 void tmio_mmc_start_dma(struct tmio_mmc_host *host,
 227                                struct mmc_data *data)
 228 {
 229         if (data->flags & MMC_DATA_READ) {
 230                 if (host->chan_rx)
 231                         tmio_mmc_start_dma_rx(host);
 232         } else {
 233                 if (host->chan_tx)
 234                         tmio_mmc_start_dma_tx(host);
 235         }
 236 }
 237
 238 static void tmio_mmc_issue_tasklet_fn(unsigned long priv)
 239 {
 240         struct tmio_mmc_host *host = (struct tmio_mmc_host *)priv;
 241         struct dma_chan *chan = NULL;
 242
 243         spin_lock_irq(&host->lock);
 244
 245         if (host && host->data) {
 246                 if (host->data->flags & MMC_DATA_READ)
 247                         chan = host->chan_rx;
 248                 else
 249                         chan = host->chan_tx;
 250         }
 251
 252         spin_unlock_irq(&host->lock);
 253
 254         tmio_mmc_enable_mmc_irqs(host, TMIO_STAT_DATAEND);
 255
 256         if (chan)
 257                 dma_async_issue_pending(chan);
 258 }
 259
 260 void tmio_mmc_request_dma(struct tmio_mmc_host *host, struct tmio_mmc_data *pdata)
 261 {
 262         /* We can only either use DMA for both Tx and Rx or not use it at all */
 263         if (!host->dma || (!host->pdev->dev.of_node &&
 264                 (!pdata->chan_priv_tx || !pdata->chan_priv_rx)))
 265                 return;
 266
 267         if (!host->chan_tx && !host->chan_rx) {
 268                 struct resource *res = platform_get_resource(host->pdev,
 269                                                              IORESOURCE_MEM, 0);
 270                 struct dma_slave_config cfg = {};
 271                 dma_cap_mask_t mask;
 272                 int ret;
 273
 274                 if (!res)
 275                         return;
 276
 277                 dma_cap_zero(mask);
 278                 dma_cap_set(DMA_SLAVE, mask);
 279
 280                 host->chan_tx = dma_request_slave_channel_compat(mask,
 281                                         host->dma->filter, pdata->chan_priv_tx,
 282                                         &host->pdev->dev, "tx");
 283                 dev_dbg(&host->pdev->dev, "%s: TX: got channel %p\n", __func__,
 284                         host->chan_tx);
 285
 286                 if (!host->chan_tx)
 287                         return;
 288
 289                 cfg.direction = DMA_MEM_TO_DEV;
 290                 cfg.dst_addr = res->start + (CTL_SD_DATA_PORT << host->bus_shift);
 291                 cfg.dst_addr_width = host->dma->dma_buswidth;
 292                 if (!cfg.dst_addr_width)
 293                         cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 294                 cfg.src_addr = 0;
 295                 ret = dmaengine_slave_config(host->chan_tx, &cfg);
 296                 if (ret < 0)
 297                         goto ecfgtx;
 298
 299                 host->chan_rx = dma_request_slave_channel_compat(mask,
 300                                         host->dma->filter, pdata->chan_priv_rx,
 301                                         &host->pdev->dev, "rx");
 302                 dev_dbg(&host->pdev->dev, "%s: RX: got channel %p\n", __func__,
 303                         host->chan_rx);
 304
 305                 if (!host->chan_rx)
 306                         goto ereqrx;
 307
 308                 cfg.direction = DMA_DEV_TO_MEM;
 309                 cfg.src_addr = cfg.dst_addr + host->pdata->dma_rx_offset;
 310                 cfg.src_addr_width = host->dma->dma_buswidth;
 311                 if (!cfg.src_addr_width)
 312                         cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 313                 cfg.dst_addr = 0;
 314                 ret = dmaengine_slave_config(host->chan_rx, &cfg);
 315                 if (ret < 0)
 316                         goto ecfgrx;
 317
 318                 host->bounce_buf = (u8 *)__get_free_page(GFP_KERNEL | GFP_DMA);
 319                 if (!host->bounce_buf)
 320                         goto ebouncebuf;
 321
 322                 init_completion(&host->dma_dataend);
 323                 tasklet_init(&host->dma_issue, tmio_mmc_issue_tasklet_fn, (unsigned long)host);
 324         }
 325
 326         tmio_mmc_enable_dma(host, true);
 327
 328         return;
 329
 330 ebouncebuf:
 331 ecfgrx:
 332         dma_release_channel(host->chan_rx);
 333         host->chan_rx = NULL;
 334 ereqrx:
 335 ecfgtx:
 336         dma_release_channel(host->chan_tx);
 337         host->chan_tx = NULL;
 338 }
 339
 340 void tmio_mmc_release_dma(struct tmio_mmc_host *host)
 341 {
 342         if (host->chan_tx) {
 343                 struct dma_chan *chan = host->chan_tx;
 344                 host->chan_tx = NULL;
 345                 dma_release_channel(chan);
 346         }
 347         if (host->chan_rx) {
 348                 struct dma_chan *chan = host->chan_rx;
 349                 host->chan_rx = NULL;
 350                 dma_release_channel(chan);
 351         }
 352         if (host->bounce_buf) {
 353                 free_pages((unsigned long)host->bounce_buf, 0);
 354                 host->bounce_buf = NULL;
 355         }
 356 }