[PATCH v2] net: ethernet: ti: cpsw: fix extra rx interrupt

[PATCH v2] net: ethernet: ti: cpsw: fix extra rx interrupt

[Grygorii Strashko]

Now RX interrupt is triggered twice every time, because in
cpsw_rx_interrupt() it is asked first and then disabled. So there will be
pending interrupt always, when RX interrupt is enabled again in NAPI
handler.

Fix it by first disabling IRQ and then do ask.

Fixes: 870915feabdc ("drivers: net: cpsw: remove disable_irq/enable_irq as irq can be masked from cpsw itself")
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
---
Hi

It requires manual backporting if selected for stable.
I can prepare separate patch for 5.4 if needed. 

 drivers/net/ethernet/ti/cpsw_priv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/ti/cpsw_priv.c b/drivers/net/ethernet/ti/cpsw_priv.c
index b833cc1d188c..707d5eb480ce 100644
--- a/drivers/net/ethernet/ti/cpsw_priv.c
+++ b/drivers/net/ethernet/ti/cpsw_priv.c
@@ -100,8 +100,8 @@ irqreturn_t cpsw_rx_interrupt(int irq, void *dev_id)
 {
 	struct cpsw_common *cpsw = dev_id;
 
-	cpdma_ctlr_eoi(cpsw->dma, CPDMA_EOI_RX);
 	writel(0, &cpsw->wr_regs->rx_en);
+	cpdma_ctlr_eoi(cpsw->dma, CPDMA_EOI_RX);
 
 	if (cpsw->quirk_irq) {
 		disable_irq_nosync(cpsw->irqs_table[0]);
-- 
2.17.1

Re: [PATCH v2] net: ethernet: ti: cpsw: fix extra rx interrupt

[David Miller]

From: Grygorii Strashko <grygorii.strashko@ti.com>
Date: Fri, 6 Dec 2019 14:28:20 +0200

> Now RX interrupt is triggered twice every time, because in
> cpsw_rx_interrupt() it is asked first and then disabled. So there will be
> pending interrupt always, when RX interrupt is enabled again in NAPI
> handler.
> 
> Fix it by first disabling IRQ and then do ask.
> 
> Fixes: 870915feabdc ("drivers: net: cpsw: remove disable_irq/enable_irq as irq can be masked from cpsw itself")
> Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>

Applied and queued up for -stable.