mmc: omap_hsmmc: fix a few bugs when setting the clock divisor
Andy Shevchenko [Fri, 6 May 2011 09:14:06 +0000 (12:14 +0300)]
There are two pieces of code which are similar, but not the same.
Each of them contains a bug.

The SYSCTL register should be read before writing to it in
omap_hsmmc_context_restore() to retain the state of the reserved bits.

Before setting the clock divisor and DTO bits the value from the SYSCTL
register should be masked properly. We were lucky to have no problems
with DTO bits. So, make sure we have clear DTO bits properly in
omap_hsmmc_set_ios().

Additionally get rid of msleep(1). The actual time is rarely higher
than 30us on OMAP 3630.

The resulting pieces of code are refactored into the
omap_hsmmc_set_clock() function.

Signed-off-by: Andy Shevchenko <ext-andriy.shevchenko@nokia.com>
Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

drivers/mmc/host/omap_hsmmc.c

index 2645bdc..bda284b 100644 (file)
@@ -612,6 +612,32 @@ static u16 calc_divisor(struct mmc_ios *ios)
        return dsor;
 }
 
+static void omap_hsmmc_set_clock(struct omap_hsmmc_host *host)
+{
+       struct mmc_ios *ios = &host->mmc->ios;
+       unsigned long regval;
+       unsigned long timeout;
+
+       dev_dbg(mmc_dev(host->mmc), "Set clock to %uHz\n", ios->clock);
+
+       omap_hsmmc_stop_clock(host);
+
+       regval = OMAP_HSMMC_READ(host->base, SYSCTL);
+       regval = regval & ~(CLKD_MASK | DTO_MASK);
+       regval = regval | (calc_divisor(ios) << 6) | (DTO << 16);
+       OMAP_HSMMC_WRITE(host->base, SYSCTL, regval);
+       OMAP_HSMMC_WRITE(host->base, SYSCTL,
+               OMAP_HSMMC_READ(host->base, SYSCTL) | ICE);
+
+       /* Wait till the ICS bit is set */
+       timeout = jiffies + msecs_to_jiffies(MMC_TIMEOUT_MS);
+       while ((OMAP_HSMMC_READ(host->base, SYSCTL) & ICS) != ICS
+               && time_before(jiffies, timeout))
+               cpu_relax();
+
+       omap_hsmmc_start_clock(host);
+}
+
 #ifdef CONFIG_PM
 
 /*
@@ -702,19 +728,7 @@ static int omap_hsmmc_context_restore(struct omap_hsmmc_host *host)
                break;
        }
 
-       omap_hsmmc_stop_clock(host);
-
-       OMAP_HSMMC_WRITE(host->base, SYSCTL,
-               (calc_divisor(ios) << 6) | (DTO << 16));
-       OMAP_HSMMC_WRITE(host->base, SYSCTL,
-               OMAP_HSMMC_READ(host->base, SYSCTL) | ICE);
-
-       timeout = jiffies + msecs_to_jiffies(MMC_TIMEOUT_MS);
-       while ((OMAP_HSMMC_READ(host->base, SYSCTL) & ICS) != ICS
-               && time_before(jiffies, timeout))
-               ;
-
-       omap_hsmmc_start_clock(host);
+       omap_hsmmc_set_clock(host);
 
        con = OMAP_HSMMC_READ(host->base, CON);
        if (ios->bus_mode == MMC_BUSMODE_OPENDRAIN)
@@ -1614,8 +1628,6 @@ static void omap_hsmmc_request(struct mmc_host *mmc, struct mmc_request *req)
 static void omap_hsmmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 {
        struct omap_hsmmc_host *host = mmc_priv(mmc);
-       unsigned long regval;
-       unsigned long timeout;
        u32 con;
        int do_send_init_stream = 0;
 
@@ -1677,22 +1689,7 @@ static void omap_hsmmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
                }
        }
 
-       omap_hsmmc_stop_clock(host);
-
-       regval = OMAP_HSMMC_READ(host->base, SYSCTL);
-       regval = regval & ~(CLKD_MASK);
-       regval = regval | (calc_divisor(ios) << 6) | (DTO << 16);
-       OMAP_HSMMC_WRITE(host->base, SYSCTL, regval);
-       OMAP_HSMMC_WRITE(host->base, SYSCTL,
-               OMAP_HSMMC_READ(host->base, SYSCTL) | ICE);
-
-       /* Wait till the ICS bit is set */
-       timeout = jiffies + msecs_to_jiffies(MMC_TIMEOUT_MS);
-       while ((OMAP_HSMMC_READ(host->base, SYSCTL) & ICS) != ICS
-               && time_before(jiffies, timeout))
-               msleep(1);
-
-       omap_hsmmc_start_clock(host);
+       omap_hsmmc_set_clock(host);
 
        if (do_send_init_stream)
                send_init_stream(host);