[PATCH v2] mxcmmc: use dmaengine API

[PATCH v2] mxcmmc: use dmaengine API

[Sascha Hauer]

This switches the mxcmmc driver to use the dmaengine API. Unlike
the old one this one is always present in the tree, even if no DMA
is implemented, hence we can remove all the #ifdefs in from the driver.
The driver automatically switches to PIO mode if no DMA support or no
suitable channel is available.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---

Arnd recognized that it's not a good idea that the driver has to
know about the dmaengine implementation (the struct imx_dma_data field).
I have a patch in my queue fixing this, but as this has to be
synchronized with the platform code, I'd like to address this in a later
patch.

 drivers/mmc/host/mxcmmc.c |  183 ++++++++++++++++++++++++++-------------------
 1 files changed, 105 insertions(+), 78 deletions(-)

diff --git a/drivers/mmc/host/mxcmmc.c b/drivers/mmc/host/mxcmmc.c
index 4428594..cc20e02 100644
--- a/drivers/mmc/host/mxcmmc.c
+++ b/drivers/mmc/host/mxcmmc.c
@@ -32,16 +32,14 @@
 #include <linux/io.h>
 #include <linux/gpio.h>
 #include <linux/regulator/consumer.h>
+#include <linux/dmaengine.h>
 
 #include <asm/dma.h>
 #include <asm/irq.h>
 #include <asm/sizes.h>
 #include <mach/mmc.h>
 
-#ifdef CONFIG_ARCH_MX2
-#include <mach/dma-mx1-mx2.h>
-#define HAS_DMA
-#endif
+#include <mach/dma.h>
 
 #define DRIVER_NAME "mxc-mmc"
 
@@ -118,7 +116,8 @@ struct mxcmci_host {
 	void __iomem		*base;
 	int			irq;
 	int			detect_irq;
-	int			dma;
+	struct dma_chan		*dma;
+	struct dma_async_tx_descriptor *desc;
 	int			do_dma;
 	int			default_irq_mask;
 	int			use_sdio;
@@ -129,7 +128,6 @@ struct mxcmci_host {
 	struct mmc_command	*cmd;
 	struct mmc_data		*data;
 
-	unsigned int		dma_nents;
 	unsigned int		datasize;
 	unsigned int		dma_dir;
 
@@ -144,6 +142,11 @@ struct mxcmci_host {
 	spinlock_t		lock;
 
 	struct regulator	*vcc;
+
+	int			burstlen;
+	int			dmareq;
+	struct dma_slave_config dma_slave_config;
+	struct imx_dma_data	dma_data;
 };
 
 static void mxcmci_set_clk_rate(struct mxcmci_host *host, unsigned int clk_ios);
@@ -206,17 +209,16 @@ static void mxcmci_softreset(struct mxcmci_host *host)
 
 	writew(0xff, host->base + MMC_REG_RES_TO);
 }
+static int mxcmci_setup_dma(struct mmc_host *mmc);
 
 static int mxcmci_setup_data(struct mxcmci_host *host, struct mmc_data *data)
 {
 	unsigned int nob = data->blocks;
 	unsigned int blksz = data->blksz;
 	unsigned int datasize = nob * blksz;
-#ifdef HAS_DMA
 	struct scatterlist *sg;
-	int i;
-	int ret;
-#endif
+	int i, nents;
+
 	if (data->flags & MMC_DATA_STREAM)
 		nob = 0xffff;
 
@@ -227,7 +229,9 @@ static int mxcmci_setup_data(struct mxcmci_host *host, struct mmc_data *data)
 	writew(blksz, host->base + MMC_REG_BLK_LEN);
 	host->datasize = datasize;
 
-#ifdef HAS_DMA
+	if (!mxcmci_use_dma(host))
+		return 0;
+
 	for_each_sg(data->sg, sg, data->sg_len, i) {
 		if (sg->offset & 3 || sg->length & 3) {
 			host->do_dma = 0;
@@ -235,34 +239,30 @@ static int mxcmci_setup_data(struct mxcmci_host *host, struct mmc_data *data)
 		}
 	}
 
-	if (data->flags & MMC_DATA_READ) {
+	if (data->flags & MMC_DATA_READ)
 		host->dma_dir = DMA_FROM_DEVICE;
-		host->dma_nents = dma_map_sg(mmc_dev(host->mmc), data->sg,
-					     data->sg_len,  host->dma_dir);
-
-		ret = imx_dma_setup_sg(host->dma, data->sg, host->dma_nents,
-				datasize,
-				host->res->start + MMC_REG_BUFFER_ACCESS,
-				DMA_MODE_READ);
-	} else {
+	else
 		host->dma_dir = DMA_TO_DEVICE;
-		host->dma_nents = dma_map_sg(mmc_dev(host->mmc), data->sg,
-					     data->sg_len,  host->dma_dir);
 
-		ret = imx_dma_setup_sg(host->dma, data->sg, host->dma_nents,
-				datasize,
-				host->res->start + MMC_REG_BUFFER_ACCESS,
-				DMA_MODE_WRITE);
-	}
+	nents = dma_map_sg(host->dma->device->dev, data->sg,
+				     data->sg_len,  host->dma_dir);
+	if (nents != data->sg_len)
+		return -EINVAL;
+
+	host->desc = host->dma->device->device_prep_slave_sg(host->dma,
+		data->sg, data->sg_len, host->dma_dir,
+		DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 
-	if (ret) {
-		dev_err(mmc_dev(host->mmc), "failed to setup DMA : %d\n", ret);
-		return ret;
+	if (!host->desc) {
+		dma_unmap_sg(host->dma->device->dev, data->sg, data->sg_len,
+				host->dma_dir);
+		host->do_dma = 0;
+		return 0; /* Fall back to PIO */
 	}
 	wmb();
 
-	imx_dma_enable(host->dma);
-#endif /* HAS_DMA */
+	dmaengine_submit(host->desc);
+
 	return 0;
 }
 
@@ -337,13 +337,11 @@ static int mxcmci_finish_data(struct mxcmci_host *host, unsigned int stat)
 	struct mmc_data *data = host->data;
 	int data_error;
 
-#ifdef HAS_DMA
 	if (mxcmci_use_dma(host)) {
-		imx_dma_disable(host->dma);
-		dma_unmap_sg(mmc_dev(host->mmc), data->sg, host->dma_nents,
+		dmaengine_terminate_all(host->dma);
+		dma_unmap_sg(host->dma->device->dev, data->sg, data->sg_len,
 				host->dma_dir);
 	}
-#endif
 
 	if (stat & STATUS_ERR_MASK) {
 		dev_dbg(mmc_dev(host->mmc), "request failed. status: 0x%08x\n",
@@ -545,7 +543,6 @@ static void mxcmci_datawork(struct work_struct *work)
 	}
 }
 
-#ifdef HAS_DMA
 static void mxcmci_data_done(struct mxcmci_host *host, unsigned int stat)
 {
 	struct mmc_data *data = host->data;
@@ -568,7 +565,6 @@ static void mxcmci_data_done(struct mxcmci_host *host, unsigned int stat)
 		mxcmci_finish_request(host, host->req);
 	}
 }
-#endif /* HAS_DMA */
 
 static void mxcmci_cmd_done(struct mxcmci_host *host, unsigned int stat)
 {
@@ -606,12 +602,10 @@ static irqreturn_t mxcmci_irq(int irq, void *devid)
 	sdio_irq = (stat & STATUS_SDIO_INT_ACTIVE) && host->use_sdio;
 	spin_unlock_irqrestore(&host->lock, flags);
 
-#ifdef HAS_DMA
 	if (mxcmci_use_dma(host) &&
 	    (stat & (STATUS_READ_OP_DONE | STATUS_WRITE_OP_DONE)))
 		writel(STATUS_READ_OP_DONE | STATUS_WRITE_OP_DONE,
 			host->base + MMC_REG_STATUS);
-#endif
 
 	if (sdio_irq) {
 		writel(STATUS_SDIO_INT_ACTIVE, host->base + MMC_REG_STATUS);
@@ -621,14 +615,14 @@ static irqreturn_t mxcmci_irq(int irq, void *devid)
 	if (stat & STATUS_END_CMD_RESP)
 		mxcmci_cmd_done(host, stat);
 
-#ifdef HAS_DMA
 	if (mxcmci_use_dma(host) &&
 		  (stat & (STATUS_DATA_TRANS_DONE | STATUS_WRITE_OP_DONE)))
 		mxcmci_data_done(host, stat);
-#endif
+
 	if (host->default_irq_mask &&
 		  (stat & (STATUS_CARD_INSERTION | STATUS_CARD_REMOVAL)))
 		mmc_detect_change(host->mmc, msecs_to_jiffies(200));
+
 	return IRQ_HANDLED;
 }
 
@@ -642,9 +636,10 @@ static void mxcmci_request(struct mmc_host *mmc, struct mmc_request *req)
 
 	host->req = req;
 	host->cmdat &= ~CMD_DAT_CONT_INIT;
-#ifdef HAS_DMA
-	host->do_dma = 1;
-#endif
+
+	if (host->dma)
+		host->do_dma = 1;
+
 	if (req->data) {
 		error = mxcmci_setup_data(host, req->data);
 		if (error) {
@@ -660,6 +655,7 @@ static void mxcmci_request(struct mmc_host *mmc, struct mmc_request *req)
 	}
 
 	error = mxcmci_start_cmd(host, req->cmd, cmdat);
+
 out:
 	if (error)
 		mxcmci_finish_request(host, req);
@@ -698,22 +694,46 @@ static void mxcmci_set_clk_rate(struct mxcmci_host *host, unsigned int clk_ios)
 			prescaler, divider, clk_in, clk_ios);
 }
 
+static int mxcmci_setup_dma(struct mmc_host *mmc)
+{
+	struct mxcmci_host *host = mmc_priv(mmc);
+	struct dma_slave_config *config = &host->dma_slave_config;
+
+	config->dst_addr = host->res->start + MMC_REG_BUFFER_ACCESS;
+	config->src_addr = host->res->start + MMC_REG_BUFFER_ACCESS;
+	config->dst_addr_width = 4;
+	config->src_addr_width = 4;
+	config->dst_maxburst = host->burstlen;
+	config->src_maxburst = host->burstlen;
+
+	return dmaengine_slave_config(host->dma, config);
+}
+
 static void mxcmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 {
 	struct mxcmci_host *host = mmc_priv(mmc);
-#ifdef HAS_DMA
-	unsigned int blen;
+	int burstlen, ret;
+
 	/*
 	 * use burstlen of 64 in 4 bit mode (--> reg value  0)
 	 * use burstlen of 16 in 1 bit mode (--> reg value 16)
 	 */
 	if (ios->bus_width == MMC_BUS_WIDTH_4)
-		blen = 0;
+		burstlen = 64;
 	else
-		blen = 16;
+		burstlen = 16;
+
+	if (mxcmci_use_dma(host) && burstlen != host->burstlen) {
+		host->burstlen = burstlen;
+		ret = mxcmci_setup_dma(mmc);
+		if (ret) {
+			dev_err(mmc_dev(host->mmc),
+				"failed to config DMA channel. Falling back to PIO\n");
+			dma_release_channel(host->dma);
+			host->do_dma = 0;
+		}
+	}
 
-	imx_dma_config_burstlen(host->dma, blen);
-#endif
 	if (ios->bus_width == MMC_BUS_WIDTH_4)
 		host->cmdat |= CMD_DAT_CONT_BUS_WIDTH_4;
 	else
@@ -794,6 +814,18 @@ static void mxcmci_init_card(struct mmc_host *host, struct mmc_card *card)
 		host->caps |= MMC_CAP_4_BIT_DATA;
 }
 
+static bool filter(struct dma_chan *chan, void *param)
+{
+	struct mxcmci_host *host = param;
+
+	if (!imx_dma_is_general_purpose(chan))
+		return false;
+
+	chan->private = &host->dma_data;
+
+	return true;
+}
+
 static const struct mmc_host_ops mxcmci_ops = {
 	.request		= mxcmci_request,
 	.set_ios		= mxcmci_set_ios,
@@ -808,6 +840,7 @@ static int mxcmci_probe(struct platform_device *pdev)
 	struct mxcmci_host *host = NULL;
 	struct resource *iores, *r;
 	int ret = 0, irq;
+	dma_cap_mask_t mask;
 
 	printk(KERN_INFO "i.MX SDHC driver\n");
 
@@ -883,29 +916,23 @@ static int mxcmci_probe(struct platform_device *pdev)
 
 	writel(host->default_irq_mask, host->base + MMC_REG_INT_CNTR);
 
-#ifdef HAS_DMA
-	host->dma = imx_dma_request_by_prio(DRIVER_NAME, DMA_PRIO_LOW);
-	if (host->dma < 0) {
-		dev_err(mmc_dev(host->mmc), "imx_dma_request_by_prio failed\n");
-		ret = -EBUSY;
-		goto out_clk_put;
-	}
-
 	r = platform_get_resource(pdev, IORESOURCE_DMA, 0);
-	if (!r) {
-		ret = -EINVAL;
-		goto out_free_dma;
+	if (r) {
+		host->dmareq = r->start;
+		host->dma_data.peripheral_type = IMX_DMATYPE_SDHC;
+		host->dma_data.priority = DMA_PRIO_LOW;
+		host->dma_data.dma_request = host->dmareq;
+		dma_cap_zero(mask);
+		dma_cap_set(DMA_SLAVE, mask);
+		host->dma = dma_request_channel(mask, filter, host);
+		if (host->dma)
+			mmc->max_seg_size = dma_get_max_seg_size(
+					host->dma->device->dev);
 	}
 
-	ret = imx_dma_config_channel(host->dma,
-				     IMX_DMA_MEMSIZE_32 | IMX_DMA_TYPE_FIFO,
-				     IMX_DMA_MEMSIZE_32 | IMX_DMA_TYPE_LINEAR,
-				     r->start, 0);
-	if (ret) {
-		dev_err(mmc_dev(host->mmc), "failed to config DMA channel\n");
-		goto out_free_dma;
-	}
-#endif
+	if (!host->dma)
+		dev_info(mmc_dev(host->mmc), "dma not available. Using PIO\n");
+
 	INIT_WORK(&host->datawork, mxcmci_datawork);
 
 	ret = request_irq(host->irq, mxcmci_irq, 0, DRIVER_NAME, host);
@@ -928,9 +955,8 @@ static int mxcmci_probe(struct platform_device *pdev)
 out_free_irq:
 	free_irq(host->irq, host);
 out_free_dma:
-#ifdef HAS_DMA
-	imx_dma_free(host->dma);
-#endif
+	if (host->dma)
+		dma_release_channel(host->dma);
 out_clk_put:
 	clk_disable(host->clk);
 	clk_put(host->clk);
@@ -960,9 +986,10 @@ static int mxcmci_remove(struct platform_device *pdev)
 
 	free_irq(host->irq, host);
 	iounmap(host->base);
-#ifdef HAS_DMA
-	imx_dma_free(host->dma);
-#endif
+
+	if (host->dma)
+		dma_release_channel(host->dma);
+
 	clk_disable(host->clk);
 	clk_put(host->clk);
 
-- 
1.7.2.3

-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

[PATCH v2] mxcmmc: use dmaengine API

[Arnd Bergmann]

On Friday 18 February 2011, Sascha Hauer wrote:
> This switches the mxcmmc driver to use the dmaengine API. Unlike
> the old one this one is always present in the tree, even if no DMA
> is implemented, hence we can remove all the #ifdefs in from the driver.
> The driver automatically switches to PIO mode if no DMA support or no
> suitable channel is available.
> 
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

The patch looks good to me, but shouldn't you also add a Kconfig
dependency or select on CONFIG_DMA_ENGINE? I don't see where that
gets set.

Acked-by: Arnd Bergmann <arnd@arndb.de>

> Arnd recognized that it's not a good idea that the driver has to
> know about the dmaengine implementation (the struct imx_dma_data field).
> I have a patch in my queue fixing this, but as this has to be
> synchronized with the platform code, I'd like to address this in a later
> patch.

Sounds good, since this patch is definitely a step forward.

	Arnd

[PATCH v2] mxcmmc: use dmaengine API

[Chris Ball]

Hi Sascha,

On Fri, Feb 18, 2011 at 02:37:02PM +0100, Arnd Bergmann wrote:
> On Friday 18 February 2011, Sascha Hauer wrote:
> > This switches the mxcmmc driver to use the dmaengine API. Unlike
> > the old one this one is always present in the tree, even if no DMA
> > is implemented, hence we can remove all the #ifdefs in from the driver.
> > The driver automatically switches to PIO mode if no DMA support or no
> > suitable channel is available.
> > 
> > Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> 
> The patch looks good to me, but shouldn't you also add a Kconfig
> dependency or select on CONFIG_DMA_ENGINE? I don't see where that
> gets set.
> 
> Acked-by: Arnd Bergmann <arnd@arndb.de>

I've pushed this to mmc-next now, but please do reply to Arnd's Kconfig
question.

Thanks,

-- 
Chris Ball   <cjb@laptop.org>   <http://printf.net/>
One Laptop Per Child

[PATCH v2] mxcmmc: use dmaengine API

[Sascha Hauer]

On Fri, Feb 18, 2011 at 02:37:02PM +0100, Arnd Bergmann wrote:
> On Friday 18 February 2011, Sascha Hauer wrote:
> > This switches the mxcmmc driver to use the dmaengine API. Unlike
> > the old one this one is always present in the tree, even if no DMA
> > is implemented, hence we can remove all the #ifdefs in from the driver.
> > The driver automatically switches to PIO mode if no DMA support or no
> > suitable channel is available.
> > 
> > Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> 
> The patch looks good to me, but shouldn't you also add a Kconfig
> dependency or select on CONFIG_DMA_ENGINE? I don't see where that
> gets set.

I was about to answer with a patch adding a select on CONFIG_DMA_ENGINE
but just realized this isn't necessary. Without dmaengine support
dma_request_channel becomes a static inline returning NULL. The mxcmmc
driver falls back to PIO then and still works.

Sascha


-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |