nagai/kernel
3
0
Fork 0
forked from mirrors/linux
Code Pull requests Activity

mmc: sdhci: Optimize delay loops

Browse source 
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: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Ludovic Desroches <ludovic.desroches@microchip.com>
This commit is contained in:
Adrian Hunter 2017-03-20 19:50:31 +02:00 committed by Ulf Hansson
parent 660fc733bd
commit 5a436cc0af
1 changed files with 9 additions and 10 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

19
drivers/mmc/host/sdhci.c
View file

@ -14,6 +14,7 @@
*/ */
#include <linux/delay.h> #include <linux/delay.h>
#include <linux/ktime.h>
#include <linux/highmem.h> #include <linux/highmem.h>
#include <linux/io.h> #include <linux/io.h>
#include <linux/module.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) void sdhci_reset(struct sdhci_host *host, u8 mask)
{ {
unsigned long timeout; ktime_t timeout;
sdhci_writeb(host, mask, SDHCI_SOFTWARE_RESET); sdhci_writeb(host, mask, SDHCI_SOFTWARE_RESET);
@ -177,18 +178,17 @@ void sdhci_reset(struct sdhci_host *host, u8 mask)
} }
/* Wait max 100 ms */ /* Wait max 100 ms */
timeout = 100; timeout = ktime_add_ms(ktime_get(), 100);
/* hw clears the bit when it's done */ /* hw clears the bit when it's done */
while (sdhci_readb(host, SDHCI_SOFTWARE_RESET) & mask) { 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", pr_err("%s: Reset 0x%x never completed.\n",
mmc_hostname(host->mmc), (int)mask); mmc_hostname(host->mmc), (int)mask);
sdhci_dumpregs(host); sdhci_dumpregs(host);
return; return;
} }
timeout--; udelay(10);
mdelay(1);
} }
} }
EXPORT_SYMBOL_GPL(sdhci_reset); 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) void sdhci_enable_clk(struct sdhci_host *host, u16 clk)
{ {
unsigned long timeout; ktime_t timeout;
clk |= SDHCI_CLOCK_INT_EN; clk |= SDHCI_CLOCK_INT_EN;
sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL); sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
/* Wait max 20 ms */ /* Wait max 20 ms */
timeout = 20; timeout = ktime_add_ms(ktime_get(), 20);
while (!((clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL)) while (!((clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL))
& SDHCI_CLOCK_INT_STABLE)) { & SDHCI_CLOCK_INT_STABLE)) {
if (timeout == 0) { if (ktime_after(ktime_get(), timeout)) {
pr_err("%s: Internal clock never stabilised.\n", pr_err("%s: Internal clock never stabilised.\n",
mmc_hostname(host->mmc)); mmc_hostname(host->mmc));
sdhci_dumpregs(host); sdhci_dumpregs(host);
return; return;
} }
timeout--;
spin_unlock_irq(&host->lock); spin_unlock_irq(&host->lock);
usleep_range(900, 1100); udelay(10);
spin_lock_irq(&host->lock); spin_lock_irq(&host->lock);
} }