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Commit d0719e59 authored by San Mehat's avatar San Mehat Committed by Daniel Walker
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mmc: msm_sdcc: Fix issue where clocks could be disabled mid transaction 



msmsdcc_enable_clocks() was incorrectly being called depending on
the state of host->clks_on. This means the busclk idle timer was never
being deleted if the clock was already on.. Bogus.

    Also fixes a possible double clk disable if the call to
del_timer_sync() in msmsdcc_disable_clocks() raced with
the busclk timer.

Signed-off-by: default avatarSan Mehat <san@google.com>
Signed-off-by: default avatarDaniel Walker <dwalker@codeaurora.org>
parent 6ac9ea69

drivers/mmc/host/msm_sdcc.c

+27 −34
Original line number Diff line number Diff line
@@ -72,21 +72,25 @@ msmsdcc_disable_clocks(struct msmsdcc_host *host, int deferr) 
		mod_timer(&host->busclk_timer, jiffies + BUSCLK_TIMEOUT);

	} else {

		del_timer_sync(&host->busclk_timer);

		/* Need to check clks_on again in case the busclk

		 * timer fired

		 */

		if (host->clks_on) {

			clk_disable(host->clk);

			clk_disable(host->pclk);

			host->clks_on = 0;

		}

	}

}



static inline int

msmsdcc_enable_clocks(struct msmsdcc_host *host)

{

	int rc;



	WARN_ON(host->clks_on);



	del_timer_sync(&host->busclk_timer);



	if (!host->clks_on) {

		rc = clk_enable(host->pclk);

		if (rc)

			return rc;
@@ -98,6 +102,7 @@ msmsdcc_enable_clocks(struct msmsdcc_host *host) 
		udelay(1 + ((3 * USEC_PER_SEC) /

		       (host->clk_rate ? host->clk_rate : msmsdcc_fmin)));

		host->clks_on = 1;

	}

	return 0;

}
@@ -180,7 +185,8 @@ msmsdcc_dma_exec_func(struct msm_dmov_cmd *cmd) 
	struct msmsdcc_host *host = (struct msmsdcc_host *)cmd->data;



	msmsdcc_writel(host, host->cmd_timeout, MMCIDATATIMER);

	msmsdcc_writel(host, (unsigned int)host->curr.xfer_size, MMCIDATALENGTH);

	msmsdcc_writel(host, (unsigned int)host->curr.xfer_size,

		       MMCIDATALENGTH);

	msmsdcc_writel(host, host->cmd_pio_irqmask, MMCIMASK1);

	msmsdcc_writel(host, host->cmd_datactrl, MMCIDATACTRL);
@@ -854,13 +860,7 @@ msmsdcc_request(struct mmc_host *mmc, struct mmc_request *mrq) 
		return;

	}



	/* Need to drop the host lock here in case

	 * the busclk wd fires 

	 */

	spin_unlock_irqrestore(&host->lock, flags);

	if (!host->clks_on)

	msmsdcc_enable_clocks(host);

	spin_lock_irqsave(&host->lock, flags);



	host->curr.mrq = mrq;
@@ -893,11 +893,10 @@ msmsdcc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) 
	int rc;

	unsigned long flags;



	if (!host->clks_on)

		msmsdcc_enable_clocks(host);



	spin_lock_irqsave(&host->lock, flags);



	msmsdcc_enable_clocks(host);



	if (ios->clock) {

		if (ios->clock != host->clk_rate) {

			rc = clk_set_rate(host->clk, ios->clock);
@@ -1026,13 +1025,9 @@ static void 
msmsdcc_busclk_expired(unsigned long _data)

{

	struct msmsdcc_host	*host = (struct msmsdcc_host *) _data;

	unsigned long 		flags;



	spin_lock_irqsave(&host->lock, flags);

	dev_info(mmc_dev(host->mmc), "Bus clock timer expired\n");

	if (host->clks_on)

		msmsdcc_disable_clocks(host, 0);

	spin_unlock_irqrestore(&host->lock, flags);

}



static int
@@ -1324,10 +1319,8 @@ msmsdcc_suspend(struct platform_device *dev, pm_message_t state) 


		if (mmc->card && mmc->card->type != MMC_TYPE_SDIO)

			rc = mmc_suspend_host(mmc, state);

		if (!rc) {

		if (!rc)

			msmsdcc_writel(host, 0, MMCIMASK0);



		}

		if (host->clks_on)

			msmsdcc_disable_clocks(host, 0);

	}