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Commit 5a436cc0 authored by Adrian Hunter's avatar Adrian Hunter Committed by Ulf Hansson
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mmc: sdhci: Optimize delay loops 



The delay loops for reset and clock enable always take at least 1 ms
because they use mdelay(1). However they can take a lot less time e.g. less
than 50us. Use ktime and reduce the delay to 10 microseconds per loop.

Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Tested-by: default avatarLudovic Desroches <ludovic.desroches@microchip.com>
parent 660fc733

drivers/mmc/host/sdhci.c

+9 −10
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
 */



#include <linux/delay.h>

#include <linux/ktime.h>

#include <linux/highmem.h>

#include <linux/io.h>

#include <linux/module.h>
@@ -165,7 +166,7 @@ static void sdhci_runtime_pm_bus_off(struct sdhci_host *host) 


void sdhci_reset(struct sdhci_host *host, u8 mask)

{

	unsigned long timeout;

	ktime_t timeout;



	sdhci_writeb(host, mask, SDHCI_SOFTWARE_RESET);
@@ -177,18 +178,17 @@ void sdhci_reset(struct sdhci_host *host, u8 mask) 
	}



	/* Wait max 100 ms */

	timeout = 100;

	timeout = ktime_add_ms(ktime_get(), 100);



	/* hw clears the bit when it's done */

	while (sdhci_readb(host, SDHCI_SOFTWARE_RESET) & mask) {

		if (timeout == 0) {

		if (ktime_after(ktime_get(), timeout)) {

			pr_err("%s: Reset 0x%x never completed.\n",

				mmc_hostname(host->mmc), (int)mask);

			sdhci_dumpregs(host);

			return;

		}

		timeout--;

		mdelay(1);

		udelay(10);

	}

}

EXPORT_SYMBOL_GPL(sdhci_reset);
@@ -1346,24 +1346,23 @@ EXPORT_SYMBOL_GPL(sdhci_calc_clk); 


void sdhci_enable_clk(struct sdhci_host *host, u16 clk)

{

	unsigned long timeout;

	ktime_t timeout;



	clk |= SDHCI_CLOCK_INT_EN;

	sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);



	/* Wait max 20 ms */

	timeout = 20;

	timeout = ktime_add_ms(ktime_get(), 20);

	while (!((clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL))

		& SDHCI_CLOCK_INT_STABLE)) {

		if (timeout == 0) {

		if (ktime_after(ktime_get(), timeout)) {

			pr_err("%s: Internal clock never stabilised.\n",

			       mmc_hostname(host->mmc));

			sdhci_dumpregs(host);

			return;

		}

		timeout--;

		spin_unlock_irq(&host->lock);

		usleep_range(900, 1100);

		udelay(10);

		spin_lock_irq(&host->lock);

	}