pci: dwc: Clear MSI interrupt status after it is handled

Message ID 1502364295-3786-1-git-send-email-faiz_abbas@ti.com
State Accepted
Headers show

Commit Message

Faiz Abbas Aug. 10, 2017, 11:24 a.m.
If the interrupt status is cleared before it is handled, it is possible
that another interrupt will trigger while servicing the previous one.
This is causing timeouts in some wireless lan cards which use pcie.
Therefore, clear MSI interrupt status after it gets serviced instead
of before calling generic_handler.

Signed-off-by: Faiz Abbas <faiz_abbas@ti.com>
---
 drivers/pci/dwc/pcie-designware-host.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Joao Pinto Aug. 18, 2017, 11:43 a.m. | #1
Hello,

Às 12:24 PM de 8/10/2017, Faiz Abbas escreveu:
> If the interrupt status is cleared before it is handled, it is possible
> that another interrupt will trigger while servicing the previous one.
> This is causing timeouts in some wireless lan cards which use pcie.
> Therefore, clear MSI interrupt status after it gets serviced instead
> of before calling generic_handler.
> 
> Signed-off-by: Faiz Abbas <faiz_abbas@ti.com>
> ---
>  drivers/pci/dwc/pcie-designware-host.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/dwc/pcie-designware-host.c b/drivers/pci/dwc/pcie-designware-host.c
> index 28ed32b..78b2584 100644
> --- a/drivers/pci/dwc/pcie-designware-host.c
> +++ b/drivers/pci/dwc/pcie-designware-host.c
> @@ -71,9 +71,9 @@ irqreturn_t dw_handle_msi_irq(struct pcie_port *pp)
>  		while ((pos = find_next_bit((unsigned long *) &val, 32,
>  					    pos)) != 32) {
>  			irq = irq_find_mapping(pp->irq_domain, i * 32 + pos);
> +			generic_handle_irq(irq);
>  			dw_pcie_wr_own_conf(pp, PCIE_MSI_INTR0_STATUS + i * 12,
>  					    4, 1 << pos);
> -			generic_handle_irq(irq);
>  			pos++;
>  		}
>  	}
> 

It makes sense.

Acked-By: Joao Pinto <jpinto@synopsys.com>
Bjorn Helgaas Aug. 22, 2017, 8:51 p.m. | #2
On Thu, Aug 10, 2017 at 04:54:55PM +0530, Faiz Abbas wrote:
> If the interrupt status is cleared before it is handled, it is possible
> that another interrupt will trigger while servicing the previous one.
> This is causing timeouts in some wireless lan cards which use pcie.
> Therefore, clear MSI interrupt status after it gets serviced instead
> of before calling generic_handler.
> 
> Signed-off-by: Faiz Abbas <faiz_abbas@ti.com>

Applied with Joao's ack to pci/host-designware for v4.14, thanks!

> ---
>  drivers/pci/dwc/pcie-designware-host.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/dwc/pcie-designware-host.c b/drivers/pci/dwc/pcie-designware-host.c
> index 28ed32b..78b2584 100644
> --- a/drivers/pci/dwc/pcie-designware-host.c
> +++ b/drivers/pci/dwc/pcie-designware-host.c
> @@ -71,9 +71,9 @@ irqreturn_t dw_handle_msi_irq(struct pcie_port *pp)
>  		while ((pos = find_next_bit((unsigned long *) &val, 32,
>  					    pos)) != 32) {
>  			irq = irq_find_mapping(pp->irq_domain, i * 32 + pos);
> +			generic_handle_irq(irq);
>  			dw_pcie_wr_own_conf(pp, PCIE_MSI_INTR0_STATUS + i * 12,
>  					    4, 1 << pos);
> -			generic_handle_irq(irq);
>  			pos++;
>  		}
>  	}
> -- 
> 2.7.4
>

Patch

diff --git a/drivers/pci/dwc/pcie-designware-host.c b/drivers/pci/dwc/pcie-designware-host.c
index 28ed32b..78b2584 100644
--- a/drivers/pci/dwc/pcie-designware-host.c
+++ b/drivers/pci/dwc/pcie-designware-host.c
@@ -71,9 +71,9 @@  irqreturn_t dw_handle_msi_irq(struct pcie_port *pp)
 		while ((pos = find_next_bit((unsigned long *) &val, 32,
 					    pos)) != 32) {
 			irq = irq_find_mapping(pp->irq_domain, i * 32 + pos);
+			generic_handle_irq(irq);
 			dw_pcie_wr_own_conf(pp, PCIE_MSI_INTR0_STATUS + i * 12,
 					    4, 1 << pos);
-			generic_handle_irq(irq);
 			pos++;
 		}
 	}