From 5a436cc0af6202265de0d2d2d35f1b4fd85caf3b Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Mon, 20 Mar 2017 19:50:31 +0200 Subject: [PATCH] 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: Adrian Hunter Signed-off-by: Ulf Hansson Tested-by: Ludovic Desroches --- drivers/mmc/host/sdhci.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 63bc33a54d0d..777c82efce1d 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -14,6 +14,7 @@ */ #include +#include #include #include #include @@ -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); }