mmc: omap: timeout counter fix

Having a loop with a counter is no timing guarentee for timing
accuracy or compiler optimizations. For e.g. the same loop counter
which runs when the MPU is running at 600MHz will timeout in around
half the time when running at 1GHz. or the example where GCC 4.5
compiles with different optimization compared to GCC 4.4. use timer
to keep track of time elapse and we use an emperical number - 1sec
for a worst case timeout.  This should never happen, and is adequate
imaginary condition for us to fail with timeout.

Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>

diff --git a/drivers/mmc/omap_hsmmc.c b/drivers/mmc/omap_hsmmc.c
index c7f76209f33cbe8a6ca23d490bf31958c121ec4c..6f2280abff91af577644e0249a175702d477524e 100644 (file)
--- a/drivers/mmc/omap_hsmmc.c
+++ b/drivers/mmc/omap_hsmmc.c
@@ -31,6 +31,9 @@
 #include <asm/io.h>
 #include <asm/arch/mmc_host_def.h>
 
+/* If we fail after 1 second wait, something is really bad */
+#define MAX_RETRY_MS   1000
+
 static int mmc_read_data(hsmmc_t *mmc_base, char *buf, unsigned int size);
 static int mmc_write_data(hsmmc_t *mmc_base, const char *buf, unsigned int siz);
 static struct mmc hsmmc_dev[2];
@@ -70,18 +73,29 @@ unsigned char mmc_board_init(hsmmc_t *mmc_base)
 
 void mmc_init_stream(hsmmc_t *mmc_base)
 {
+       ulong start;
 
        writel(readl(&mmc_base->con) | INIT_INITSTREAM, &mmc_base->con);
 
        writel(MMC_CMD0, &mmc_base->cmd);
-       while (!(readl(&mmc_base->stat) & CC_MASK))
-               ;
+       start = get_timer(0);
+       while (!(readl(&mmc_base->stat) & CC_MASK)) {
+               if (get_timer(0) - start > MAX_RETRY_MS) {
+                       printf("%s: timedout waiting for cc!\n", __func__);
+                       return;
+               }
+       }
        writel(CC_MASK, &mmc_base->stat)
                ;
        writel(MMC_CMD0, &mmc_base->cmd)
                ;
-       while (!(readl(&mmc_base->stat) & CC_MASK))
-               ;
+       start = get_timer(0);
+       while (!(readl(&mmc_base->stat) & CC_MASK)) {
+               if (get_timer(0) - start > MAX_RETRY_MS) {
+                       printf("%s: timedout waiting for cc2!\n", __func__);
+                       return;
+               }
+       }
        writel(readl(&mmc_base->con) & ~INIT_INITSTREAM, &mmc_base->con);
 }
 
@@ -91,16 +105,28 @@ static int mmc_init_setup(struct mmc *mmc)
        hsmmc_t *mmc_base = (hsmmc_t *)mmc->priv;
        unsigned int reg_val;
        unsigned int dsor;
+       ulong start;
 
        mmc_board_init(mmc_base);
 
        writel(readl(&mmc_base->sysconfig) | MMC_SOFTRESET,
                &mmc_base->sysconfig);
-       while ((readl(&mmc_base->sysstatus) & RESETDONE) == 0)
-               ;
+       start = get_timer(0);
+       while ((readl(&mmc_base->sysstatus) & RESETDONE) == 0) {
+               if (get_timer(0) - start > MAX_RETRY_MS) {
+                       printf("%s: timedout waiting for cc2!\n", __func__);
+                       return TIMEOUT;
+               }
+       }
        writel(readl(&mmc_base->sysctl) | SOFTRESETALL, &mmc_base->sysctl);
-       while ((readl(&mmc_base->sysctl) & SOFTRESETALL) != 0x0)
-               ;
+       start = get_timer(0);
+       while ((readl(&mmc_base->sysctl) & SOFTRESETALL) != 0x0) {
+               if (get_timer(0) - start > MAX_RETRY_MS) {
+                       printf("%s: timedout waiting for softresetall!\n",
+                               __func__);
+                       return TIMEOUT;
+               }
+       }
        writel(DTW_1_BITMODE | SDBP_PWROFF | SDVS_3V0, &mmc_base->hctl);
        writel(readl(&mmc_base->capa) | VS30_3V0SUP | VS18_1V8SUP,
                &mmc_base->capa);
@@ -116,8 +142,13 @@ static int mmc_init_setup(struct mmc *mmc)
                (ICE_STOP | DTO_15THDTO | CEN_DISABLE));
        mmc_reg_out(&mmc_base->sysctl, ICE_MASK | CLKD_MASK,
                (dsor << CLKD_OFFSET) | ICE_OSCILLATE);
-       while ((readl(&mmc_base->sysctl) & ICS_MASK) == ICS_NOTREADY)
-               ;
+       start = get_timer(0);
+       while ((readl(&mmc_base->sysctl) & ICS_MASK) == ICS_NOTREADY) {
+               if (get_timer(0) - start > MAX_RETRY_MS) {
+                       printf("%s: timedout waiting for ics!\n", __func__);
+                       return TIMEOUT;
+               }
+       }
        writel(readl(&mmc_base->sysctl) | CEN_ENABLE, &mmc_base->sysctl);
 
        writel(readl(&mmc_base->hctl) | SDBP_PWRON, &mmc_base->hctl);
@@ -137,14 +168,23 @@ static int mmc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
 {
        hsmmc_t *mmc_base = (hsmmc_t *)mmc->priv;
        unsigned int flags, mmc_stat;
-       unsigned int retry = 0x100000;
+       ulong start;
 
-
-       while ((readl(&mmc_base->pstate) & DATI_MASK) == DATI_CMDDIS)
-               ;
+       start = get_timer(0);
+       while ((readl(&mmc_base->pstate) & DATI_MASK) == DATI_CMDDIS) {
+               if (get_timer(0) - start > MAX_RETRY_MS) {
+                       printf("%s: timedout waiting for cmddis!\n", __func__);
+                       return TIMEOUT;
+               }
+       }
        writel(0xFFFFFFFF, &mmc_base->stat);
-       while (readl(&mmc_base->stat))
-               ;
+       start = get_timer(0);
+       while (readl(&mmc_base->stat)) {
+               if (get_timer(0) - start > MAX_RETRY_MS) {
+                       printf("%s: timedout waiting for stat!\n", __func__);
+                       return TIMEOUT;
+               }
+       }
        /*
         * CMDREG
         * CMDIDX[13:8] : Command index
@@ -200,15 +240,14 @@ static int mmc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
        writel(cmd->cmdarg, &mmc_base->arg);
        writel((cmd->cmdidx << 24) | flags, &mmc_base->cmd);
 
+       start = get_timer(0);
        do {
                mmc_stat = readl(&mmc_base->stat);
-               retry--;
-       } while ((mmc_stat == 0) && (retry > 0));
-
-       if (retry == 0) {
-               printf("%s : timeout: No status update\n", __func__);
-               return TIMEOUT;
-       }
+               if (get_timer(0) - start > MAX_RETRY_MS) {
+                       printf("%s : timeout: No status update\n", __func__);
+                       return TIMEOUT;
+               }
+       } while (!mmc_stat);
 
        if ((mmc_stat & IE_CTO) != 0)
                return TIMEOUT;
@@ -253,8 +292,14 @@ static int mmc_read_data(hsmmc_t *mmc_base, char *buf, unsigned int size)
        count /= 4;
 
        while (size) {
+               ulong start = get_timer(0);
                do {
                        mmc_stat = readl(&mmc_base->stat);
+                       if (get_timer(0) - start > MAX_RETRY_MS) {
+                               printf("%s: timedout waiting for status!\n",
+                                               __func__);
+                               return TIMEOUT;
+                       }
                } while (mmc_stat == 0);
 
                if ((mmc_stat & ERRI_MASK) != 0)
@@ -298,8 +343,14 @@ static int mmc_write_data(hsmmc_t *mmc_base, const char *buf, unsigned int size)
        count /= 4;
 
        while (size) {
+               ulong start = get_timer(0);
                do {
                        mmc_stat = readl(&mmc_base->stat);
+                       if (get_timer(0) - start > MAX_RETRY_MS) {
+                               printf("%s: timedout waiting for status!\n",
+                                               __func__);
+                               return TIMEOUT;
+                       }
                } while (mmc_stat == 0);
 
                if ((mmc_stat & ERRI_MASK) != 0)
@@ -334,6 +385,7 @@ static void mmc_set_ios(struct mmc *mmc)
 {
        hsmmc_t *mmc_base = (hsmmc_t *)mmc->priv;
        unsigned int dsor = 0;
+       ulong start;
 
        /* configue bus width */
        switch (mmc->bus_width) {
@@ -372,8 +424,13 @@ static void mmc_set_ios(struct mmc *mmc)
        mmc_reg_out(&mmc_base->sysctl, ICE_MASK | CLKD_MASK,
                                (dsor << CLKD_OFFSET) | ICE_OSCILLATE);
 
-       while ((readl(&mmc_base->sysctl) & ICS_MASK) == ICS_NOTREADY)
-               ;
+       start = get_timer(0);
+       while ((readl(&mmc_base->sysctl) & ICS_MASK) == ICS_NOTREADY) {
+               if (get_timer(0) - start > MAX_RETRY_MS) {
+                       printf("%s: timedout waiting for ics!\n", __func__);
+                       return;
+               }
+       }
        writel(readl(&mmc_base->sysctl) | CEN_ENABLE, &mmc_base->sysctl);
 }