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Commit 9d2fc80f authored by Russell King's avatar Russell King Committed by Chris Ball
Browse files

mmc: sdhci-esdhc-imx: avoid DMA to kernel stack 



sdhci-esdhc-imx tries to DMA to the kernel stack when tuning the
interface, which causes dma-debug to complain.  Fix this by kmallocing
a buffer to hold the received tuning pattern.

Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
Tested-by: default avatarMarkus Pargmann <mpa@pengutronix.de>
Tested-by: default avatarStephen Warren <swarren@nvidia.com>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: default avatarChris Ball <chris@printf.net>
parent 1771059c

drivers/mmc/host/sdhci-esdhc-imx.c

+16 −9
Original line number Diff line number Diff line
@@ -711,13 +711,12 @@ static void esdhc_request_done(struct mmc_request *mrq) 
	complete(&mrq->completion);

}



static int esdhc_send_tuning_cmd(struct sdhci_host *host, u32 opcode)

static int esdhc_send_tuning_cmd(struct sdhci_host *host, u32 opcode,

				 struct scatterlist *sg)

{

	struct mmc_command cmd = {0};

	struct mmc_request mrq = {NULL};

	struct mmc_data data = {0};

	struct scatterlist sg;

	char tuning_pattern[ESDHC_TUNING_BLOCK_PATTERN_LEN];



	cmd.opcode = opcode;

	cmd.arg = 0;
@@ -726,11 +725,9 @@ static int esdhc_send_tuning_cmd(struct sdhci_host *host, u32 opcode) 
	data.blksz = ESDHC_TUNING_BLOCK_PATTERN_LEN;

	data.blocks = 1;

	data.flags = MMC_DATA_READ;

	data.sg = &sg;

	data.sg = sg;

	data.sg_len = 1;



	sg_init_one(&sg, tuning_pattern, sizeof(tuning_pattern));



	mrq.cmd = &cmd;

	mrq.cmd->mrq = &mrq;

	mrq.data = &data;
@@ -770,13 +767,21 @@ static void esdhc_post_tuning(struct sdhci_host *host) 


static int esdhc_executing_tuning(struct sdhci_host *host, u32 opcode)

{

	struct scatterlist sg;

	char *tuning_pattern;

	int min, max, avg, ret;



	tuning_pattern = kmalloc(ESDHC_TUNING_BLOCK_PATTERN_LEN, GFP_KERNEL);

	if (!tuning_pattern)

		return -ENOMEM;



	sg_init_one(&sg, tuning_pattern, ESDHC_TUNING_BLOCK_PATTERN_LEN);



	/* find the mininum delay first which can pass tuning */

	min = ESDHC_TUNE_CTRL_MIN;

	while (min < ESDHC_TUNE_CTRL_MAX) {

		esdhc_prepare_tuning(host, min);

		if (!esdhc_send_tuning_cmd(host, opcode))

		if (!esdhc_send_tuning_cmd(host, opcode, &sg))

			break;

		min += ESDHC_TUNE_CTRL_STEP;

	}
@@ -785,7 +790,7 @@ static int esdhc_executing_tuning(struct sdhci_host *host, u32 opcode) 
	max = min + ESDHC_TUNE_CTRL_STEP;

	while (max < ESDHC_TUNE_CTRL_MAX) {

		esdhc_prepare_tuning(host, max);

		if (esdhc_send_tuning_cmd(host, opcode)) {

		if (esdhc_send_tuning_cmd(host, opcode, &sg)) {

			max -= ESDHC_TUNE_CTRL_STEP;

			break;

		}
@@ -795,9 +800,11 @@ static int esdhc_executing_tuning(struct sdhci_host *host, u32 opcode) 
	/* use average delay to get the best timing */

	avg = (min + max) / 2;

	esdhc_prepare_tuning(host, avg);

	ret = esdhc_send_tuning_cmd(host, opcode);

	ret = esdhc_send_tuning_cmd(host, opcode, &sg);

	esdhc_post_tuning(host);



	kfree(tuning_pattern);



	dev_dbg(mmc_dev(host->mmc), "tunning %s at 0x%x ret %d\n",

		ret ? "failed" : "passed", avg, ret);