scsi: ufs: make sure all interrupts are processed

[ Upstream commit 7f6ba4f12e6cbfdefbb95cfd8fc67ece6c15d799 ]

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>
Reviewed-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 9bd26ef..50d1574 100644 (file)
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -4397,19 +4397,30 @@ 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;
 }