mmc: sh_mmcif: add DMA support
The MMCIF controller on sh-mobile platforms can use the DMA controller for data
transfers. Interface to the SH dmaengine driver to enable DMA. We also have to
lower the maximum number of segments to match with the number od DMA
descriptors on SuperH, this doesn't significantly affect driver's PIO
performance.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/drivers/mmc/host/sh_mmcif.c b/drivers/mmc/host/sh_mmcif.c
index b2f261c..d09a2b3 100644
--- a/drivers/mmc/host/sh_mmcif.c
+++ b/drivers/mmc/host/sh_mmcif.c
@@ -20,12 +20,14 @@
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
+#include <linux/dmaengine.h>
#include <linux/mmc/card.h>
#include <linux/mmc/core.h>
#include <linux/mmc/host.h>
#include <linux/mmc/mmc.h>
#include <linux/mmc/sdio.h>
#include <linux/mmc/sh_mmcif.h>
+#include <linux/pagemap.h>
#include <linux/platform_device.h>
#define DRIVER_NAME "sh_mmcif"
@@ -162,8 +164,13 @@
long timeout;
void __iomem *addr;
struct completion intr_wait;
-};
+ /* DMA support */
+ struct dma_chan *chan_rx;
+ struct dma_chan *chan_tx;
+ struct completion dma_complete;
+ unsigned int dma_sglen;
+};
static inline void sh_mmcif_bitset(struct sh_mmcif_host *host,
unsigned int reg, u32 val)
@@ -177,6 +184,208 @@
writel(~val & readl(host->addr + reg), host->addr + reg);
}
+#ifdef CONFIG_SH_MMCIF_DMA
+static void mmcif_dma_complete(void *arg)
+{
+ struct sh_mmcif_host *host = arg;
+ dev_dbg(&host->pd->dev, "Command completed\n");
+
+ if (WARN(!host->data, "%s: NULL data in DMA completion!\n",
+ dev_name(&host->pd->dev)))
+ return;
+
+ if (host->data->flags & MMC_DATA_READ)
+ dma_unmap_sg(&host->pd->dev, host->data->sg, host->dma_sglen,
+ DMA_FROM_DEVICE);
+ else
+ dma_unmap_sg(&host->pd->dev, host->data->sg, host->dma_sglen,
+ DMA_TO_DEVICE);
+
+ complete(&host->dma_complete);
+}
+
+static void sh_mmcif_start_dma_rx(struct sh_mmcif_host *host)
+{
+ struct scatterlist *sg = host->data->sg;
+ struct dma_async_tx_descriptor *desc = NULL;
+ struct dma_chan *chan = host->chan_rx;
+ dma_cookie_t cookie = -EINVAL;
+ int ret;
+
+ ret = dma_map_sg(&host->pd->dev, sg, host->data->sg_len, DMA_FROM_DEVICE);
+ if (ret > 0) {
+ host->dma_sglen = ret;
+ desc = chan->device->device_prep_slave_sg(chan, sg, ret,
+ DMA_FROM_DEVICE, DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+ }
+
+ if (desc) {
+ desc->callback = mmcif_dma_complete;
+ desc->callback_param = host;
+ cookie = desc->tx_submit(desc);
+ if (cookie < 0) {
+ desc = NULL;
+ ret = cookie;
+ } else {
+ sh_mmcif_bitset(host, MMCIF_CE_BUF_ACC, BUF_ACC_DMAREN);
+ chan->device->device_issue_pending(chan);
+ }
+ }
+ dev_dbg(&host->pd->dev, "%s(): mapped %d -> %d, cookie %d\n",
+ __func__, host->data->sg_len, ret, cookie);
+
+ if (!desc) {
+ /* DMA failed, fall back to PIO */
+ if (ret >= 0)
+ ret = -EIO;
+ host->chan_rx = NULL;
+ host->dma_sglen = 0;
+ dma_release_channel(chan);
+ /* Free the Tx channel too */
+ chan = host->chan_tx;
+ if (chan) {
+ host->chan_tx = NULL;
+ dma_release_channel(chan);
+ }
+ dev_warn(&host->pd->dev,
+ "DMA failed: %d, falling back to PIO\n", ret);
+ sh_mmcif_bitclr(host, MMCIF_CE_BUF_ACC, BUF_ACC_DMAREN | BUF_ACC_DMAWEN);
+ }
+
+ dev_dbg(&host->pd->dev, "%s(): desc %p, cookie %d, sg[%d]\n", __func__,
+ desc, cookie, host->data->sg_len);
+}
+
+static void sh_mmcif_start_dma_tx(struct sh_mmcif_host *host)
+{
+ struct scatterlist *sg = host->data->sg;
+ struct dma_async_tx_descriptor *desc = NULL;
+ struct dma_chan *chan = host->chan_tx;
+ dma_cookie_t cookie = -EINVAL;
+ int ret;
+
+ ret = dma_map_sg(&host->pd->dev, sg, host->data->sg_len, DMA_TO_DEVICE);
+ if (ret > 0) {
+ host->dma_sglen = ret;
+ desc = chan->device->device_prep_slave_sg(chan, sg, ret,
+ DMA_TO_DEVICE, DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+ }
+
+ if (desc) {
+ desc->callback = mmcif_dma_complete;
+ desc->callback_param = host;
+ cookie = desc->tx_submit(desc);
+ if (cookie < 0) {
+ desc = NULL;
+ ret = cookie;
+ } else {
+ sh_mmcif_bitset(host, MMCIF_CE_BUF_ACC, BUF_ACC_DMAWEN);
+ chan->device->device_issue_pending(chan);
+ }
+ }
+ dev_dbg(&host->pd->dev, "%s(): mapped %d -> %d, cookie %d\n",
+ __func__, host->data->sg_len, ret, cookie);
+
+ if (!desc) {
+ /* DMA failed, fall back to PIO */
+ if (ret >= 0)
+ ret = -EIO;
+ host->chan_tx = NULL;
+ host->dma_sglen = 0;
+ dma_release_channel(chan);
+ /* Free the Rx channel too */
+ chan = host->chan_rx;
+ if (chan) {
+ host->chan_rx = NULL;
+ dma_release_channel(chan);
+ }
+ dev_warn(&host->pd->dev,
+ "DMA failed: %d, falling back to PIO\n", ret);
+ sh_mmcif_bitclr(host, MMCIF_CE_BUF_ACC, BUF_ACC_DMAREN | BUF_ACC_DMAWEN);
+ }
+
+ dev_dbg(&host->pd->dev, "%s(): desc %p, cookie %d\n", __func__,
+ desc, cookie);
+}
+
+static bool sh_mmcif_filter(struct dma_chan *chan, void *arg)
+{
+ dev_dbg(chan->device->dev, "%s: slave data %p\n", __func__, arg);
+ chan->private = arg;
+ return true;
+}
+
+static void sh_mmcif_request_dma(struct sh_mmcif_host *host,
+ struct sh_mmcif_plat_data *pdata)
+{
+ host->dma_sglen = 0;
+
+ /* We can only either use DMA for both Tx and Rx or not use it at all */
+ if (pdata->dma) {
+ dma_cap_mask_t mask;
+
+ dma_cap_zero(mask);
+ dma_cap_set(DMA_SLAVE, mask);
+
+ host->chan_tx = dma_request_channel(mask, sh_mmcif_filter,
+ &pdata->dma->chan_priv_tx);
+ dev_dbg(&host->pd->dev, "%s: TX: got channel %p\n", __func__,
+ host->chan_tx);
+
+ if (!host->chan_tx)
+ return;
+
+ host->chan_rx = dma_request_channel(mask, sh_mmcif_filter,
+ &pdata->dma->chan_priv_rx);
+ dev_dbg(&host->pd->dev, "%s: RX: got channel %p\n", __func__,
+ host->chan_rx);
+
+ if (!host->chan_rx) {
+ dma_release_channel(host->chan_tx);
+ host->chan_tx = NULL;
+ return;
+ }
+
+ init_completion(&host->dma_complete);
+ }
+}
+
+static void sh_mmcif_release_dma(struct sh_mmcif_host *host)
+{
+ sh_mmcif_bitclr(host, MMCIF_CE_BUF_ACC, BUF_ACC_DMAREN | BUF_ACC_DMAWEN);
+ /* Descriptors are freed automatically */
+ if (host->chan_tx) {
+ struct dma_chan *chan = host->chan_tx;
+ host->chan_tx = NULL;
+ dma_release_channel(chan);
+ }
+ if (host->chan_rx) {
+ struct dma_chan *chan = host->chan_rx;
+ host->chan_rx = NULL;
+ dma_release_channel(chan);
+ }
+
+ host->dma_sglen = 0;
+}
+#else
+static void sh_mmcif_start_dma_tx(struct sh_mmcif_host *host)
+{
+}
+
+static void sh_mmcif_start_dma_rx(struct sh_mmcif_host *host)
+{
+}
+
+static void sh_mmcif_request_dma(struct sh_mmcif_host *host,
+ struct sh_mmcif_plat_data *pdata)
+{
+ /* host->chan_tx, host->chan_tx and host->dma_sglen are all zero */
+}
+
+static void sh_mmcif_release_dma(struct sh_mmcif_host *host)
+{
+}
+#endif
static void sh_mmcif_clock_control(struct sh_mmcif_host *host, unsigned int clk)
{
@@ -564,7 +773,20 @@
}
sh_mmcif_get_response(host, cmd);
if (host->data) {
- ret = sh_mmcif_data_trans(host, mrq, cmd->opcode);
+ if (!host->dma_sglen) {
+ ret = sh_mmcif_data_trans(host, mrq, cmd->opcode);
+ } else {
+ long time =
+ wait_for_completion_interruptible_timeout(&host->dma_complete,
+ host->timeout);
+ if (!time)
+ ret = -ETIMEDOUT;
+ else if (time < 0)
+ ret = time;
+ sh_mmcif_bitclr(host, MMCIF_CE_BUF_ACC,
+ BUF_ACC_DMAREN | BUF_ACC_DMAWEN);
+ host->dma_sglen = 0;
+ }
if (ret < 0)
mrq->data->bytes_xfered = 0;
else
@@ -622,6 +844,15 @@
break;
}
host->data = mrq->data;
+ if (mrq->data) {
+ if (mrq->data->flags & MMC_DATA_READ) {
+ if (host->chan_rx)
+ sh_mmcif_start_dma_rx(host);
+ } else {
+ if (host->chan_tx)
+ sh_mmcif_start_dma_tx(host);
+ }
+ }
sh_mmcif_start_cmd(host, mrq, mrq->cmd);
host->data = NULL;
@@ -806,14 +1037,18 @@
mmc->caps = MMC_CAP_MMC_HIGHSPEED;
if (pd->caps)
mmc->caps |= pd->caps;
- mmc->max_segs = 128;
+ mmc->max_segs = 32;
mmc->max_blk_size = 512;
- mmc->max_blk_count = 65535;
- mmc->max_req_size = mmc->max_blk_size * mmc->max_blk_count;
+ mmc->max_req_size = PAGE_CACHE_SIZE * mmc->max_segs;
+ mmc->max_blk_count = mmc->max_req_size / mmc->max_blk_size;
mmc->max_seg_size = mmc->max_req_size;
sh_mmcif_sync_reset(host);
platform_set_drvdata(pdev, host);
+
+ /* See if we also get DMA */
+ sh_mmcif_request_dma(host, pd);
+
mmc_add_host(mmc);
ret = request_irq(irq[0], sh_mmcif_intr, 0, "sh_mmc:error", host);
@@ -852,6 +1087,7 @@
int irq[2];
mmc_remove_host(host->mmc);
+ sh_mmcif_release_dma(host);
if (host->addr)
iounmap(host->addr);