2018-05-03 11:16:37

by Asutosh Das (asd)

Subject: [PATCH v2 08/10] scsi: ufs: make sure all interrupts are processed

From: Venkat Gopalakrishnan <[email protected]>

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 <[email protected]>
Signed-off-by: Asutosh Das <[email protected]>
---
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 c35a076..09b7a3f 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -5383,19 +5383,30 @@ 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.

2018-05-16 21:14:30

by Subhash Jadavani

Subject: Re: [PATCH v2 08/10] scsi: ufs: make sure all interrupts are processed

On 2018-05-03 04:07, Asutosh Das wrote:
> From: Venkat Gopalakrishnan <[email protected]>
>
> 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 <[email protected]>
> Signed-off-by: Asutosh Das <[email protected]>
> ---
> 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 c35a076..09b7a3f 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -5383,19 +5383,30 @@ 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;
> }

Looks good to me.
Reviewed-by: Subhash Jadavani <[email protected]>

--
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a Linux Foundation Collaborative Project