linux-kernel - Re: [PATCH] drivers/spi/atmel_spi.c: prevent premature irqs

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Message-ID: <4DA2C0C0.6050903@atmel.com>
Date:	Mon, 11 Apr 2011 10:50:08 +0200
From:	Nicolas Ferre <nicolas.ferre@...el.com>
To:	"Voss, Nikolaus" <N.Voss@...nmann.de>
CC:	"'Linux Kernel'" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] drivers/spi/atmel_spi.c: prevent premature irqs

Le 11/04/2011 08:53, Voss, Nikolaus :
> When restarting a kernel using kexec, filled rx buffers on SPI master
> interface reliably crash the kernel. This patch disables rx interrupts
> on startup to avoid this. Interrupts will be regulary enabled at start
> of a new SPI master transfer.
> 
> Signed-off-by: Nikolaus Voss <n.voss@...nmann.de>
> ---
>  drivers/spi/atmel_spi.c |    3 +++
>  1 files changed, 3 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/spi/atmel_spi.c b/drivers/spi/atmel_spi.c
> index 1a478bf..d17f14c 100644
> --- a/drivers/spi/atmel_spi.c
> +++ b/drivers/spi/atmel_spi.c
> @@ -811,6 +811,9 @@ static int __init atmel_spi_probe(struct platform_device *pdev)
>  	as->irq = irq;
>  	as->clk = clk;
>  
> +	/* disable rx interrupts to avoid premature irq triggering */
> +	spi_writel(as, IDR, SPI_BIT(RXBUFF) | SPI_BIT(ENDRX) | SPI_BIT(OVRES));
> +

What about something like this?

/* disable all interrupts to avoid premature irq triggering */
spi_writel(as, IDR, 0xffffffff);


>  	ret = request_irq(irq, atmel_spi_interrupt, 0,
>  			dev_name(&pdev->dev), master);
>  	if (ret)

Best regards,
-- 
Nicolas Ferre

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