[PATCH 1/1] mmc: mmci: add threaded irq to abort DPSM of non-functional state

From: Ludovic Barre
Date: Wed Nov 13 2019 - 12:25:46 EST


From: Ludovic Barre <ludovic.barre@xxxxxx>

If datatimeout occurs on R1B request, the Data Path State Machine stays
in busy and is non-functional. Only a reset aborts the DPSM.

Like a reset must be outside of critical section, this patch adds
threaded irq function to release state machine. In this case,
the mmc_request_done is called at the end of threaded irq and
skipped into irq handler.

Signed-off-by: Ludovic Barre <ludovic.barre@xxxxxx>
---
drivers/mmc/host/mmci.c | 44 ++++++++++++++++++++++++++++++++++++-----
drivers/mmc/host/mmci.h | 1 +
2 files changed, 40 insertions(+), 5 deletions(-)

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index 40e72c30ea84..ec6e249c87ca 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -556,6 +556,9 @@ static void mmci_dma_error(struct mmci_host *host)
static void
mmci_request_end(struct mmci_host *host, struct mmc_request *mrq)
{
+ if (host->irq_action == IRQ_WAKE_THREAD)
+ return;
+
writel(0, host->base + MMCICOMMAND);

BUG_ON(host->data);
@@ -1321,6 +1324,7 @@ mmci_cmd_irq(struct mmci_host *host, struct mmc_command *cmd,
} else if (host->variant->busy_timeout && busy_resp &&
status & MCI_DATATIMEOUT) {
cmd->error = -ETIMEDOUT;
+ host->irq_action = IRQ_WAKE_THREAD;
} else {
cmd->resp[0] = readl(base + MMCIRESPONSE0);
cmd->resp[1] = readl(base + MMCIRESPONSE1);
@@ -1532,9 +1536,9 @@ static irqreturn_t mmci_irq(int irq, void *dev_id)
{
struct mmci_host *host = dev_id;
u32 status;
- int ret = 0;

spin_lock(&host->lock);
+ host->irq_action = IRQ_HANDLED;

do {
status = readl(host->base + MMCISTATUS);
@@ -1574,12 +1578,41 @@ static irqreturn_t mmci_irq(int irq, void *dev_id)
if (host->variant->busy_detect_flag)
status &= ~host->variant->busy_detect_flag;

- ret = 1;
} while (status);

spin_unlock(&host->lock);

- return IRQ_RETVAL(ret);
+ return host->irq_action;
+}
+
+/*
+ * mmci_irq_threaded is call if the mmci host need to release state machines
+ * before to terminate the request.
+ * If datatimeout occurs on R1B request, the Data Path State Machine stays
+ * in busy and is non-functional. Only a reset can to abort the DPSM.
+ */
+static irqreturn_t mmci_irq_threaded(int irq, void *dev_id)
+{
+ struct mmci_host *host = dev_id;
+ 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);
+
+ host->irq_action = IRQ_HANDLED;
+ mmci_request_end(host, host->mrq);
+ spin_unlock_irqrestore(&host->lock, flags);
+
+ return host->irq_action;
}

static void mmci_request(struct mmc_host *mmc, struct mmc_request *mrq)
@@ -2071,8 +2104,9 @@ static int mmci_probe(struct amba_device *dev,
goto clk_disable;
}

- ret = devm_request_irq(&dev->dev, dev->irq[0], mmci_irq, IRQF_SHARED,
- DRIVER_NAME " (cmd)", host);
+ ret = devm_request_threaded_irq(&dev->dev, dev->irq[0], mmci_irq,
+ mmci_irq_threaded, IRQF_SHARED,
+ DRIVER_NAME " (cmd)", host);
if (ret)
goto clk_disable;

diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h
index 158e1231aa23..5e63c0596364 100644
--- a/drivers/mmc/host/mmci.h
+++ b/drivers/mmc/host/mmci.h
@@ -412,6 +412,7 @@ struct mmci_host {

struct timer_list timer;
unsigned int oldstat;
+ u32 irq_action;

/* pio stuff */
struct sg_mapping_iter sg_miter;
--
2.17.1