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Commit 68c5ed59 authored by Ben Dooks's avatar Ben Dooks Committed by Linus Torvalds
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s3cmci: DMA fixes 



Fixes for the DMA transfer mode of the driver to try and improve the state
of the code:

- Ensure that dma_complete is set during the end of the command phase
  so that transfers do not stall awaiting the completion

- Update the DMA debugging to provide a bit more useful information
  such as how many DMA descriptors where not processed and print the
  DMA addresses in hexadecimal.

- Fix the DMA channel request code to actually request DMA for the
  S3CMCI block instead of whatever '0' signified.

- Add fallback to PIO if we cannot get the DMA channel, as many of the
  devices with this block only have a limited number of DMA channels.

- Only try and claim and free the DMA channel if we are trying to use it.

This improves the driver DMA code to the point where it can now identify a
card and read the partition table.  However the DMA can still stall when
trying to move data between the host and memory.

Signed-off-by: default avatarBen Dooks <ben@simtec.co.uk>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 26f14947

drivers/mmc/host/s3cmci.c

+47 −15
Original line number Diff line number Diff line
@@ -183,6 +183,21 @@ static inline bool s3cmci_host_usedma(struct s3cmci_host *host) 
#endif

}



/**

 * s3cmci_host_canpio - return true if host has pio code available

 *

 * Return true if the driver has been compiled with the PIO support code

 * available.

 */

static inline bool s3cmci_host_canpio(void)

{

#ifdef CONFIG_MMC_S3C_PIO

	return true;

#else

	return false;

#endif

}



static inline u32 enable_imask(struct s3cmci_host *host, u32 imask)

{

	u32 newmask;
@@ -786,6 +801,7 @@ static void s3cmci_dma_done_callback(struct s3c2410_dma_chan *dma_ch, 
	dbg(host, dbg_dma, "DMA FINISHED Size:%i DSTA:%08x DCNT:%08x\n",

		size, mci_dsta, mci_dcnt);



	host->dma_complete = 1;

	host->complete_what = COMPLETION_FINALIZE;



out:
@@ -816,7 +832,8 @@ static void finalize_request(struct s3cmci_host *host) 
	if (cmd->data && (cmd->error == 0) &&

	    (cmd->data->error == 0)) {

		if (s3cmci_host_usedma(host) && (!host->dma_complete)) {

			dbg(host, dbg_dma, "DMA Missing!\n");

			dbg(host, dbg_dma, "DMA Missing (%d)!\n",

			    host->dma_complete);

			return;

		}

	}
@@ -1065,7 +1082,7 @@ static int s3cmci_prepare_pio(struct s3cmci_host *host, struct mmc_data *data) 
static int s3cmci_prepare_dma(struct s3cmci_host *host, struct mmc_data *data)

{

	int dma_len, i;

	int rw = (data->flags & MMC_DATA_WRITE) ? 1 : 0;

	int rw = data->flags & MMC_DATA_WRITE;



	BUG_ON((data->flags & BOTH_DIR) == BOTH_DIR);
@@ -1073,7 +1090,7 @@ static int s3cmci_prepare_dma(struct s3cmci_host *host, struct mmc_data *data) 
	s3c2410_dma_ctrl(host->dma, S3C2410_DMAOP_FLUSH);



	dma_len = dma_map_sg(mmc_dev(host->mmc), data->sg, data->sg_len,

			     (rw) ? DMA_TO_DEVICE : DMA_FROM_DEVICE);

			     rw ? DMA_TO_DEVICE : DMA_FROM_DEVICE);



	if (dma_len == 0)

		return -ENOMEM;
@@ -1084,11 +1101,11 @@ static int s3cmci_prepare_dma(struct s3cmci_host *host, struct mmc_data *data) 
	for (i = 0; i < dma_len; i++) {

		int res;



		dbg(host, dbg_dma, "enqueue %i:%u@%u\n", i,

		dbg(host, dbg_dma, "enqueue %i: %08x@%u\n", i,

		    sg_dma_address(&data->sg[i]),

		    sg_dma_len(&data->sg[i]));



		res = s3c2410_dma_enqueue(host->dma, (void *) host,

		res = s3c2410_dma_enqueue(host->dma, host,

					  sg_dma_address(&data->sg[i]),

					  sg_dma_len(&data->sg[i]));
@@ -1581,8 +1598,6 @@ static int __devinit s3cmci_probe(struct platform_device *pdev) 
	host->complete_what 	= COMPLETION_NONE;

	host->pio_active 	= XFER_NONE;



	host->dma		= S3CMCI_DMA;



#ifdef CONFIG_MMC_S3C_PIODMA

	host->dodma		= host->pdata->dma;

#endif
@@ -1665,10 +1680,21 @@ static int __devinit s3cmci_probe(struct platform_device *pdev) 
		gpio_direction_input(host->pdata->gpio_wprotect);

	}



	if (s3c2410_dma_request(S3CMCI_DMA, &s3cmci_dma_client, NULL) < 0) {

		dev_err(&pdev->dev, "unable to get DMA channel.\n");

	/* depending on the dma state, get a dma channel to use. */



	if (s3cmci_host_usedma(host)) {

		host->dma = s3c2410_dma_request(DMACH_SDI, &s3cmci_dma_client,

						host);

		if (host->dma < 0) {

			dev_err(&pdev->dev, "cannot get DMA channel.\n");

			if (!s3cmci_host_canpio()) {

				ret = -EBUSY;

				goto probe_free_gpio_wp;

			} else {

				dev_warn(&pdev->dev, "falling back to PIO.\n");

				host->dodma = 0;

			}

		}

	}



	host->clk = clk_get(&pdev->dev, "sdi");
@@ -1676,7 +1702,7 @@ static int __devinit s3cmci_probe(struct platform_device *pdev) 
		dev_err(&pdev->dev, "failed to find clock source.\n");

		ret = PTR_ERR(host->clk);

		host->clk = NULL;

		goto probe_free_host;

		goto probe_free_dma;

	}



	ret = clk_enable(host->clk);
@@ -1738,6 +1764,10 @@ static int __devinit s3cmci_probe(struct platform_device *pdev) 
 clk_free:

	clk_put(host->clk);



 probe_free_dma:

	if (s3cmci_host_usedma(host))

		s3c2410_dma_free(host->dma, &s3cmci_dma_client);



 probe_free_gpio_wp:

	if (host->pdata->gpio_wprotect)

		gpio_free(host->pdata->gpio_wprotect);
@@ -1796,7 +1826,9 @@ static int __devexit s3cmci_remove(struct platform_device *pdev) 
	clk_put(host->clk);



	tasklet_disable(&host->pio_tasklet);

	s3c2410_dma_free(S3CMCI_DMA, &s3cmci_dma_client);



	if (s3cmci_host_usedma(host))

		s3c2410_dma_free(host->dma, &s3cmci_dma_client);



	free_irq(host->irq, host);

drivers/mmc/host/s3cmci.h

+0 −3
Original line number Diff line number Diff line
@@ -8,9 +8,6 @@ 
 * published by the Free Software Foundation.

 */



/* FIXME: DMA Resource management ?! */

#define S3CMCI_DMA 0



enum s3cmci_waitfor {

	COMPLETION_NONE,

	COMPLETION_FINALIZE,