diff mbox

[net-next,1/1] drivers: net: cpsw: irq not disabled in cpsw isr in particular sequence

Message ID 1367495531-19470-1-git-send-email-mugunthanvnm@ti.com
State Accepted, archived
Delegated to: David Miller
Headers show

Commit Message

Mugunthan V N May 2, 2013, 11:52 a.m. UTC
In CPSW NAPI, after processing all interrupts IRQ is enabled and then book
keeping irq_enabled is updated. In random cases when a packet is transmitted
or received between processing packets and IRQ enabled, then just after
enabled IRQ and before irq_enabled is updated, ISR is called so IRQs are
not disabled as irq_enabled is still false and CPU gets locked in CPSW ISR.

By changing the sequence as update the irq_enabled and then enable IRQ
fixes the issue. This issue is not captured always as it is a timing issue
whether Tx or Rx IRQ is invoked between packet processing and enable IRQ.

Cc: Sebastian Siewior <bigeasy@linutronix.de>
Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
---
 drivers/net/ethernet/ti/cpsw.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Sebastian Andrzej Siewior May 2, 2013, 12:37 p.m. UTC | #1
* Mugunthan V N | 2013-05-02 17:22:11 [+0530]:

>In CPSW NAPI, after processing all interrupts IRQ is enabled and then book
>keeping irq_enabled is updated. In random cases when a packet is transmitted
>or received between processing packets and IRQ enabled, then just after
>enabled IRQ and before irq_enabled is updated, ISR is called so IRQs are
>not disabled as irq_enabled is still false and CPU gets locked in CPSW ISR.
>
>By changing the sequence as update the irq_enabled and then enable IRQ
>fixes the issue. This issue is not captured always as it is a timing issue
>whether Tx or Rx IRQ is invoked between packet processing and enable IRQ.

Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

Sebastian
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David Miller May 2, 2013, 8:52 p.m. UTC | #2
From: Mugunthan V N <mugunthanvnm@ti.com>
Date: Thu, 2 May 2013 17:22:11 +0530

> In CPSW NAPI, after processing all interrupts IRQ is enabled and then book
> keeping irq_enabled is updated. In random cases when a packet is transmitted
> or received between processing packets and IRQ enabled, then just after
> enabled IRQ and before irq_enabled is updated, ISR is called so IRQs are
> not disabled as irq_enabled is still false and CPU gets locked in CPSW ISR.
> 
> By changing the sequence as update the irq_enabled and then enable IRQ
> fixes the issue. This issue is not captured always as it is a timing issue
> whether Tx or Rx IRQ is invoked between packet processing and enable IRQ.
> 
> Cc: Sebastian Siewior <bigeasy@linutronix.de>
> Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>

Applied, thanks.
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diff mbox

Patch

diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c
index 59c4391..21a5b29 100644
--- a/drivers/net/ethernet/ti/cpsw.c
+++ b/drivers/net/ethernet/ti/cpsw.c
@@ -555,8 +555,8 @@  static int cpsw_poll(struct napi_struct *napi, int budget)
 		cpdma_ctlr_eoi(priv->dma, CPDMA_EOI_RX);
 		prim_cpsw = cpsw_get_slave_priv(priv, 0);
 		if (prim_cpsw->irq_enabled == false) {
-			cpsw_enable_irq(priv);
 			prim_cpsw->irq_enabled = true;
+			cpsw_enable_irq(priv);
 		}
 	}