[PATCH 2/2] mmc: mmci: add unstuck feature

[Ludovic Barre]

From: Ludovic Barre <ludovic.ba...@st.com>

On busy_timeout feature if busy is too long on R1B command
a datatimeout occurs and a specific actions is needed to clear
the DPSM bit:
-reset the controller to clear the DPSM bit.
-restore registers: clk, pwr, datactrl.

Signed-off-by: Ludovic Barre <ludovic.ba...@st.com>
---
 drivers/mmc/host/mmci.c | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index 40e72c30ea84..dafba4e0afc5 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -1320,7 +1320,7 @@ mmci_cmd_irq(struct mmci_host *host, struct mmc_command 
*cmd,
                cmd->error = -EILSEQ;
        } else if (host->variant->busy_timeout && busy_resp &&
                   status & MCI_DATATIMEOUT) {
-               cmd->error = -ETIMEDOUT;
+               cmd->error = -EDEADLK;
        } else {
                cmd->resp[0] = readl(base + MMCIRESPONSE0);
                cmd->resp[1] = readl(base + MMCIRESPONSE1);
@@ -1332,7 +1332,6 @@ mmci_cmd_irq(struct mmci_host *host, struct mmc_command 
*cmd,
                if (host->data) {
                        /* Terminate the DMA transfer */
                        mmci_dma_error(host);
-
                        mmci_stop_data(host);
                        if (host->variant->cmdreg_stop && cmd->error) {
                                mmci_stop_command(host);
@@ -1787,6 +1786,25 @@ static int mmci_sig_volt_switch(struct mmc_host *mmc, 
struct mmc_ios *ios)
        return ret;
 }
 
+static void mmci_hw_unstuck(struct mmc_host *mmc)
+{
+       struct mmci_host *host = mmc_priv(mmc);
+       unsigned long flags;
+
+       if (host->rst) {
+               reset_control_assert(host->rst);
+               udelay(2);
+               reset_control_deassert(host->rst);
+       }
+
+       spin_lock_irqsave(&host->lock, flags);
+       writel(host->clk_reg, host->base + MMCICLOCK);
+       writel(host->pwr_reg, host->base + MMCIPOWER);
+       writel(MCI_IRQENABLE | host->variant->start_err,
+              host->base + MMCIMASK0);
+       spin_unlock_irqrestore(&host->lock, flags);
+}
+
 static struct mmc_host_ops mmci_ops = {
        .request        = mmci_request,
        .pre_req        = mmci_pre_request,
@@ -1795,6 +1813,7 @@ static struct mmc_host_ops mmci_ops = {
        .get_ro         = mmc_gpio_get_ro,
        .get_cd         = mmci_get_cd,
        .start_signal_voltage_switch = mmci_sig_volt_switch,
+       .hw_unstuck     = mmci_hw_unstuck,
 };
 
 static int mmci_of_parse(struct device_node *np, struct mmc_host *mmc)
-- 
2.17.1