[Linux-stm32] [PATCH v4 10/10] mmc: mmci: Add busydetect timeout

[Linus Walleij]

Add a timeout for busydetect IRQs using a delayed work.
It might happen (and does happen) on Ux500 that the first
busy detect IRQ appears and not the second one. This will
make the host hang indefinitely waiting for the second
IRQ to appear.

Calculate the busy timeout unconditionally in
mmci_start_command() using the code developed for STM32
and use this as a timeout for the command.

This makes the eMMC work again on Skomer.

Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
---
ChangeLog v3->v4:
- Use the calculated command busy timeout from the core
  or the same calculated default as for STM32.
ChangeLog v2->v3:
- Rebased.
ChangeLog v1->v2:
- No changes
---
 drivers/mmc/host/mmci.c | 30 +++++++++++++++++++++++++++---
 drivers/mmc/host/mmci.h |  1 +
 2 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index 478f71dc7f34..12df1c231177 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -37,6 +37,7 @@
 #include <linux/pinctrl/consumer.h>
 #include <linux/reset.h>
 #include <linux/gpio/consumer.h>
+#include <linux/workqueue.h>
 
 #include <asm/div64.h>
 #include <asm/io.h>
@@ -740,6 +741,8 @@ static bool ux500_busy_complete(struct mmci_host *host, u32 status, u32 err_msk)
 			host->busy_status |= status & (MCI_CMDSENT | MCI_CMDRESPEND);
 			writel(host->variant->busy_detect_mask, base + MMCICLEAR);
 			host->busy_state = MMCI_BUSY_WAITING_FOR_END_IRQ;
+			schedule_delayed_work(&host->busy_timeout_work,
+					      msecs_to_jiffies(host->cmd->busy_timeout));
 		} else {
 			dev_dbg(mmc_dev(host->mmc),
 				"lost busy status when waiting for busy start IRQ\n");
@@ -751,6 +754,7 @@ static bool ux500_busy_complete(struct mmci_host *host, u32 status, u32 err_msk)
 		if (status & host->variant->busy_detect_flag) {
 			host->busy_status |= status & (MCI_CMDSENT | MCI_CMDRESPEND);
 			writel(host->variant->busy_detect_mask, base + MMCICLEAR);
+			cancel_delayed_work_sync(&host->busy_timeout_work);
 			ux500_busy_clear_mask_done(host);
 		} else {
 			dev_dbg(mmc_dev(host->mmc),
@@ -1295,10 +1299,11 @@ mmci_start_command(struct mmci_host *host, struct mmc_command *cmd, u32 c)
 	host->busy_status = 0;
 	host->busy_state = MMCI_BUSY_DONE;
 
-	if (host->variant->busy_timeout && cmd->flags & MMC_RSP_BUSY) {
-		if (!cmd->busy_timeout)
-			cmd->busy_timeout = 10 * MSEC_PER_SEC;
+	/* Assign a default timeout if the core does not provide one */
+	if (!cmd->busy_timeout)
+		cmd->busy_timeout = 10 * MSEC_PER_SEC;
 
+	if (host->variant->busy_timeout && cmd->flags & MMC_RSP_BUSY) {
 		if (cmd->busy_timeout > host->mmc->max_busy_timeout)
 			clks = (unsigned long long)host->mmc->max_busy_timeout * host->cclk;
 		else
@@ -1486,6 +1491,22 @@ mmci_cmd_irq(struct mmci_host *host, struct mmc_command *cmd,
 	}
 }
 
+/*
+ * This busy timeout worker is used to "kick" the command IRQ if a
+ * busy detect IRQ fails to appear in reasonable time. Only used on
+ * variants with busy detection IRQ delivery.
+ */
+static void busy_timeout_work(struct work_struct *work)
+{
+	struct mmci_host *host =
+		container_of(work, struct mmci_host, busy_timeout_work.work);
+	u32 status;
+
+	dev_dbg(mmc_dev(host->mmc), "timeout waiting for busy IRQ\n");
+	status = readl(host->base + MMCISTATUS);
+	mmci_cmd_irq(host, host->cmd, status);
+}
+
 static int mmci_get_rx_fifocnt(struct mmci_host *host, u32 status, int remain)
 {
 	return remain - (readl(host->base + MMCIFIFOCNT) << 2);
@@ -2299,6 +2320,9 @@ static int mmci_probe(struct amba_device *dev,
 			goto clk_disable;
 	}
 
+	if (host->variant->busy_detect && host->ops->busy_complete)
+		INIT_DELAYED_WORK(&host->busy_timeout_work, busy_timeout_work);
+
 	writel(MCI_IRQENABLE | variant->start_err, host->base + MMCIMASK0);
 
 	amba_set_drvdata(dev, mmc);
diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h
index 12a7bbd3ce26..95d3d0a6049b 100644
--- a/drivers/mmc/host/mmci.h
+++ b/drivers/mmc/host/mmci.h
@@ -451,6 +451,7 @@ struct mmci_host {
 	void			*dma_priv;
 
 	s32			next_cookie;
+	struct delayed_work	busy_timeout_work;
 };
 
 #define dma_inprogress(host)	((host)->dma_in_progress)

-- 
2.40.1