mmc: mmci: add hardware busy timeout feature

In the stm32_sdmmc variant, the datatimer is active not only during
data transfers with the DPSM, but also while waiting for the busyend
IRQs from commands having the MMC_RSP_BUSY flag set. This leads to an
incorrect IRQ being raised to signal MCI_DATATIMEOUT error, which
simply breaks the behaviour.

Address this by updating the datatimer value before sending a command
having the MMC_RSP_BUSY flag set. To inform the mmc core about the
maximum supported busy timeout, which also depends on the current
clock rate, set ->max_busy_timeout (in ms).

Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index e14003e..ed0b402 100644 (file)
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -1075,6 +1075,7 @@ static void
 mmci_start_command(struct mmci_host *host, struct mmc_command *cmd, u32 c)
 {
        void __iomem *base = host->base;
+       unsigned long long clks;
 
        dev_dbg(mmc_dev(host->mmc), "op %02x arg %08x flags %08x\n",
            cmd->opcode, cmd->arg, cmd->flags);
@@ -1097,6 +1098,16 @@ mmci_start_command(struct mmci_host *host, struct mmc_command *cmd, u32 c)
                else
                        c |= host->variant->cmdreg_srsp;
        }
+
+       if (host->variant->busy_timeout && cmd->flags & MMC_RSP_BUSY) {
+               if (!cmd->busy_timeout)
+                       cmd->busy_timeout = 10 * MSEC_PER_SEC;
+
+               clks = (unsigned long long)cmd->busy_timeout * host->cclk;
+               do_div(clks, MSEC_PER_SEC);
+               writel_relaxed(clks, host->base + MMCIDATATIMER);
+       }
+
        if (/*interrupt*/0)
                c |= MCI_CPSM_INTERRUPT;
 
@@ -1201,6 +1212,7 @@ static void
 mmci_cmd_irq(struct mmci_host *host, struct mmc_command *cmd,
             unsigned int status)
 {
+       u32 err_msk = MCI_CMDCRCFAIL | MCI_CMDTIMEOUT;
        void __iomem *base = host->base;
        bool sbc, busy_resp;
 
@@ -1215,8 +1227,11 @@ mmci_cmd_irq(struct mmci_host *host, struct mmc_command *cmd,
         * handling. Note that we tag on any latent IRQs postponed
         * due to waiting for busy status.
         */
-       if (!((status|host->busy_status) &
-             (MCI_CMDCRCFAIL|MCI_CMDTIMEOUT|MCI_CMDSENT|MCI_CMDRESPEND)))
+       if (host->variant->busy_timeout && busy_resp)
+               err_msk |= MCI_DATATIMEOUT;
+
+       if (!((status | host->busy_status) &
+             (err_msk | MCI_CMDSENT | MCI_CMDRESPEND)))
                return;
 
        /* Handle busy detection on DAT0 if the variant supports it. */
@@ -1235,8 +1250,7 @@ mmci_cmd_irq(struct mmci_host *host, struct mmc_command *cmd,
                 * while, to allow it to be set, but tests indicates that it
                 * isn't needed.
                 */
-               if (!host->busy_status &&
-                   !(status & (MCI_CMDCRCFAIL|MCI_CMDTIMEOUT)) &&
+               if (!host->busy_status && !(status & err_msk) &&
                    (readl(base + MMCISTATUS) & host->variant->busy_detect_flag)) {
 
                        writel(readl(base + MMCIMASK0) |
@@ -1290,6 +1304,9 @@ mmci_cmd_irq(struct mmci_host *host, struct mmc_command *cmd,
                cmd->error = -ETIMEDOUT;
        } else if (status & MCI_CMDCRCFAIL && cmd->flags & MMC_RSP_CRC) {
                cmd->error = -EILSEQ;
+       } else if (host->variant->busy_timeout && busy_resp &&
+                  status & MCI_DATATIMEOUT) {
+               cmd->error = -ETIMEDOUT;
        } else {
                cmd->resp[0] = readl(base + MMCIRESPONSE0);
                cmd->resp[1] = readl(base + MMCIRESPONSE1);
@@ -1583,6 +1600,20 @@ static void mmci_request(struct mmc_host *mmc, struct mmc_request *mrq)
        spin_unlock_irqrestore(&host->lock, flags);
 }
 
+static void mmci_set_max_busy_timeout(struct mmc_host *mmc)
+{
+       struct mmci_host *host = mmc_priv(mmc);
+       u32 max_busy_timeout = 0;
+
+       if (!host->variant->busy_detect)
+               return;
+
+       if (host->variant->busy_timeout && mmc->actual_clock)
+               max_busy_timeout = ~0UL / (mmc->actual_clock / MSEC_PER_SEC);
+
+       mmc->max_busy_timeout = max_busy_timeout;
+}
+
 static void mmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 {
        struct mmci_host *host = mmc_priv(mmc);
@@ -1687,6 +1718,8 @@ static void mmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
        else
                mmci_set_clkreg(host, ios->clock);
 
+       mmci_set_max_busy_timeout(mmc);
+
        if (host->ops && host->ops->set_pwrreg)
                host->ops->set_pwrreg(host, pwr);
        else
@@ -1957,7 +1990,6 @@ static int mmci_probe(struct amba_device *dev,
                        mmci_write_datactrlreg(host,
                                               host->variant->busy_dpsm_flag);
                mmc->caps |= MMC_CAP_WAIT_WHILE_BUSY;
-               mmc->max_busy_timeout = 0;
        }
 
        /* Prepare a CMD12 - needed to clear the DPSM on some variants. */

diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h
index 833236e..d8b7f67 100644 (file)
--- a/drivers/mmc/host/mmci.h
+++ b/drivers/mmc/host/mmci.h
@@ -287,6 +287,8 @@ struct mmci_host;
  * @signal_direction: input/out direction of bus signals can be indicated
  * @pwrreg_clkgate: MMCIPOWER register must be used to gate the clock
  * @busy_detect: true if the variant supports busy detection on DAT0.
+ * @busy_timeout: true if the variant starts data timer when the DPSM
+ *               enter in Wait_R or Busy state.
  * @busy_dpsm_flag: bitmask enabling busy detection in the DPSM
  * @busy_detect_flag: bitmask identifying the bit in the MMCISTATUS register
  *                   indicating that the card is busy
@@ -333,6 +335,7 @@ struct variant_data {
        u8                      signal_direction:1;
        u8                      pwrreg_clkgate:1;
        u8                      busy_detect:1;
+       u8                      busy_timeout:1;
        u32                     busy_dpsm_flag;
        u32                     busy_detect_flag;
        u32                     busy_detect_mask;