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Subject[PATCH 1/1] scsi: ufs: make sure all interrupts are processed
Date
From: Venkat Gopalakrishnan <venkatg@codeaurora.org>

As multiple requests are submitted to the ufs host controller in
parallel there could be instances where the command completion
interrupt arrives later for a request that is already processed
earlier as the corresponding doorbell was cleared when handling
the previous interrupt. Read the interrupt status in a loop after
processing the received interrupt to catch such interrupts and
handle it.

Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>
Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
---
drivers/scsi/ufs/ufshcd.c | 27 +++++++++++++++++++--------
1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 8af2af3..58d81de 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -5357,19 +5357,30 @@ static irqreturn_t ufshcd_intr(int irq, void *__hba)
u32 intr_status, enabled_intr_status;
irqreturn_t retval = IRQ_NONE;
struct ufs_hba *hba = __hba;
+ int retries = hba->nutrs;

spin_lock(hba->host->host_lock);
intr_status = ufshcd_readl(hba, REG_INTERRUPT_STATUS);
- enabled_intr_status =
- intr_status & ufshcd_readl(hba, REG_INTERRUPT_ENABLE);

- if (intr_status)
- ufshcd_writel(hba, intr_status, REG_INTERRUPT_STATUS);
+ /*
+ * There could be max of hba->nutrs reqs in flight and in worst case
+ * if the reqs get finished 1 by 1 after the interrupt status is
+ * read, make sure we handle them by checking the interrupt status
+ * again in a loop until we process all of the reqs before returning.
+ */
+ do {
+ enabled_intr_status =
+ intr_status & ufshcd_readl(hba, REG_INTERRUPT_ENABLE);
+ if (intr_status)
+ ufshcd_writel(hba, intr_status, REG_INTERRUPT_STATUS);
+ if (enabled_intr_status) {
+ ufshcd_sl_intr(hba, enabled_intr_status);
+ retval = IRQ_HANDLED;
+ }
+
+ intr_status = ufshcd_readl(hba, REG_INTERRUPT_STATUS);
+ } while (intr_status && --retries);

- if (enabled_intr_status) {
- ufshcd_sl_intr(hba, enabled_intr_status);
- retval = IRQ_HANDLED;
- }
spin_unlock(hba->host->host_lock);
return retval;
}
--
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
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