On Fri, May 09, 2014 at 04:43:30PM +0200, Boris BREZILLON wrote:
> sam9x5 SoCs have the following errata:
> "RTC: Interrupt Mask Register cannot be used
> Interrupt Mask Register read always returns 0."
>
> Hence we should not rely on what IMR claims about already masked IRQs
> and just disable all IRQs.
>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx> # v3.10+
> Signed-off-by: Boris BREZILLON <boris.brezillon@xxxxxxxxxxxxxxxxxx>
> Acked-by: Nicolas Ferre <nicolas.ferre@xxxxxxxxx>
Reviewed-by: Johan Hovold <jhovold@xxxxxxxxx>
Looks good, but for the future: Why do you break the comment lines you
added at column 60?
Thanks,
Johan
> ---
> Hello,
>
> Again, sorry for the noise, but I forgot to add Nicolas' ack and to keep
> Andrew and the stable ML in cc.
>
> Best Regards,
>
> Boris
>
> Changes since v3:
> - fix commit message and comment
> Changes since v2:
> - removed unused variable 'mask'
> Changes since v1:
> - use a macro to define IRQs bitmask
> - read IMR register to ensure the write to IDR has been flushed
> - quote atmel's datasheet errata in commit message
> - comment the code to describe why we're not using IMR to disable
> the interrupts
>
> arch/arm/mach-at91/sysirq_mask.c | 22 +++++++++++++---------
> 1 file changed, 13 insertions(+), 9 deletions(-)
>
> diff --git a/arch/arm/mach-at91/sysirq_mask.c b/arch/arm/mach-at91/sysirq_mask.c
> index 2ba694f..f8bc351 100644
> --- a/arch/arm/mach-at91/sysirq_mask.c
> +++ b/arch/arm/mach-at91/sysirq_mask.c
> @@ -25,24 +25,28 @@
>
> #include "generic.h"
>
> -#define AT91_RTC_IDR 0x24 /* Interrupt Disable Register */
> -#define AT91_RTC_IMR 0x28 /* Interrupt Mask Register */
> +#define AT91_RTC_IDR 0x24 /* Interrupt Disable Register */
> +#define AT91_RTC_IMR 0x28 /* Interrupt Mask Register */
> +#define AT91_RTC_IRQ_MASK 0x1f /* Available IRQs mask */
>
> void __init at91_sysirq_mask_rtc(u32 rtc_base)
> {
> void __iomem *base;
> - u32 mask;
>
> base = ioremap(rtc_base, 64);
> if (!base)
> return;
>
> - mask = readl_relaxed(base + AT91_RTC_IMR);
> - if (mask) {
> - pr_info("AT91: Disabling rtc irq\n");
> - writel_relaxed(mask, base + AT91_RTC_IDR);
> - (void)readl_relaxed(base + AT91_RTC_IMR); /* flush */
> - }
> + /*
> + * sam9x5 SoCs have the following errata:
> + * "RTC: Interrupt Mask Register cannot be used
> + * Interrupt Mask Register read always returns 0."
> + *
> + * Hence we're not relying on IMR values to disable
> + * interrupts.
> + */
> + writel_relaxed(AT91_RTC_IRQ_MASK, base + AT91_RTC_IDR);
> + (void)readl_relaxed(base + AT91_RTC_IMR); /* flush */
>
> iounmap(base);
> }
--
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