On 09/05/2014 13:01, Boris BREZILLON :
> The sam9g25 and sam9g35 have the following errata:
Cf. below...
> "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 the IRQs.
>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx> # v3.10+
> Signed-off-by: Boris BREZILLON <boris.brezillon@xxxxxxxxxxxxxxxxxx>
> ---
> Hello,
>
> Sorry for the noise, I just forgot to remove the mask variable in my
> previous version.
>
> Best Regards,
>
> Boris
>
> 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..1527dda 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 */
> - }
> + /*
> + * The sam9g25 and sam9g35 have the following errata:
Actually all chips in what we call the "5 series" or "sam9x5" (sam9g15,
sam9g25, sam9x25, sam9g35 and sam9x35). And... no, the sam9g45 is not
part of that series ;-)
> + * "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);
> }
Okay for me (maybe change the comment as it can puzzle some users):
Acked-by: Nicolas Ferre <nicolas.ferre@xxxxxxxxx>
Thanks, bye,
--
Nicolas Ferre
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