mmc: sdhci: Program a relatively accurate SW timeout value

sdhci has a 10 second timeout to catch devices that stop responding.
In the case of quirk SDHCI_QUIRK2_DISABLE_HW_TIMEOUT, instead of
programming 10 second arbitrary value, calculate the total time it would
take for the entire transfer to happen and program the timeout value
accordingly.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index b229354..1c828e0 100644 (file)
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -738,6 +738,39 @@ static unsigned int sdhci_target_timeout(struct sdhci_host *host,
        return target_timeout;
 }
 
+static void sdhci_calc_sw_timeout(struct sdhci_host *host,
+                                 struct mmc_command *cmd)
+{
+       struct mmc_data *data = cmd->data;
+       struct mmc_host *mmc = host->mmc;
+       struct mmc_ios *ios = &mmc->ios;
+       unsigned char bus_width = 1 << ios->bus_width;
+       unsigned int blksz;
+       unsigned int freq;
+       u64 target_timeout;
+       u64 transfer_time;
+
+       target_timeout = sdhci_target_timeout(host, cmd, data);
+       target_timeout *= NSEC_PER_USEC;
+
+       if (data) {
+               blksz = data->blksz;
+               freq = host->mmc->actual_clock ? : host->clock;
+               transfer_time = (u64)blksz * NSEC_PER_SEC * (8 / bus_width);
+               do_div(transfer_time, freq);
+               /* multiply by '2' to account for any unknowns */
+               transfer_time = transfer_time * 2;
+               /* calculate timeout for the entire data */
+               host->data_timeout = data->blocks * target_timeout +
+                                    transfer_time;
+       } else {
+               host->data_timeout = target_timeout;
+       }
+
+       if (host->data_timeout)
+               host->data_timeout += MMC_CMD_TRANSFER_TIME;
+}
+
 static u8 sdhci_calc_timeout(struct sdhci_host *host, struct mmc_command *cmd,
                             bool *too_big)
 {
@@ -831,6 +864,7 @@ static void sdhci_set_timeout(struct sdhci_host *host, struct mmc_command *cmd)
 
                if (too_big &&
                    host->quirks2 & SDHCI_QUIRK2_DISABLE_HW_TIMEOUT) {
+                       sdhci_calc_sw_timeout(host, cmd);
                        sdhci_set_data_timeout_irq(host, false);
                } else if (!(host->ier & SDHCI_INT_DATA_TIMEOUT)) {
                        sdhci_set_data_timeout_irq(host, true);
@@ -845,6 +879,8 @@ static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_command *cmd)
        u8 ctrl;
        struct mmc_data *data = cmd->data;
 
+       host->data_timeout = 0;
+
        if (sdhci_data_line_cmd(cmd))
                sdhci_set_timeout(host, cmd);
 
@@ -1198,13 +1234,6 @@ void sdhci_send_command(struct sdhci_host *host, struct mmc_command *cmd)
                mdelay(1);
        }
 
-       timeout = jiffies;
-       if (!cmd->data && cmd->busy_timeout > 9000)
-               timeout += DIV_ROUND_UP(cmd->busy_timeout, 1000) * HZ + HZ;
-       else
-               timeout += 10 * HZ;
-       sdhci_mod_timer(host, cmd->mrq, timeout);
-
        host->cmd = cmd;
        if (sdhci_data_line_cmd(cmd)) {
                WARN_ON(host->data_cmd);
@@ -1244,6 +1273,15 @@ void sdhci_send_command(struct sdhci_host *host, struct mmc_command *cmd)
            cmd->opcode == MMC_SEND_TUNING_BLOCK_HS200)
                flags |= SDHCI_CMD_DATA;
 
+       timeout = jiffies;
+       if (host->data_timeout)
+               timeout += nsecs_to_jiffies(host->data_timeout);
+       else if (!cmd->data && cmd->busy_timeout > 9000)
+               timeout += DIV_ROUND_UP(cmd->busy_timeout, 1000) * HZ + HZ;
+       else
+               timeout += 10 * HZ;
+       sdhci_mod_timer(host, cmd->mrq, timeout);
+
        sdhci_writew(host, SDHCI_MAKE_CMD(cmd->opcode, flags), SDHCI_COMMAND);
 }
 EXPORT_SYMBOL_GPL(sdhci_send_command);

diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index f6555c0..23966f8 100644 (file)
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -332,6 +332,14 @@ struct sdhci_adma2_64_desc {
 /* Allow for a a command request and a data request at the same time */
 #define SDHCI_MAX_MRQS         2
 
+/*
+ * 48bit command and 136 bit response in 100KHz clock could take upto 2.48ms.
+ * However since the start time of the command, the time between
+ * command and response, and the time between response and start of data is
+ * not known, set the command transfer time to 10ms.
+ */
+#define MMC_CMD_TRANSFER_TIME  (10 * NSEC_PER_MSEC) /* max 10 ms */
+
 enum sdhci_cookie {
        COOKIE_UNMAPPED,
        COOKIE_PRE_MAPPED,      /* mapped by sdhci_pre_req() */
@@ -555,6 +563,8 @@ struct sdhci_host {
        /* Host SDMA buffer boundary. */
        u32                     sdma_boundary;
 
+       u64                     data_timeout;
+
        unsigned long private[0] ____cacheline_aligned;
 };