* [RESEND PATCH v4] ARM: at91: fix at91_sysirq_mask_rtc for sam9x5 SoCs
@ 2014-05-09 14:43 Boris BREZILLON
2014-05-09 14:51 ` Johan Hovold
0 siblings, 1 reply; 3+ messages in thread
From: Boris BREZILLON @ 2014-05-09 14:43 UTC (permalink / raw)
To: linux-arm-kernel
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@linux-foundation.org>
Cc: <stable@vger.kernel.org> # v3.10+
Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
---
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);
}
--
1.8.3.2
^ permalink raw reply related [flat|nested] 3+ messages in thread* [RESEND PATCH v4] ARM: at91: fix at91_sysirq_mask_rtc for sam9x5 SoCs
2014-05-09 14:43 [RESEND PATCH v4] ARM: at91: fix at91_sysirq_mask_rtc for sam9x5 SoCs Boris BREZILLON
@ 2014-05-09 14:51 ` Johan Hovold
2014-05-09 15:00 ` Boris BREZILLON
0 siblings, 1 reply; 3+ messages in thread
From: Johan Hovold @ 2014-05-09 14:51 UTC (permalink / raw)
To: linux-arm-kernel
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@linux-foundation.org>
> Cc: <stable@vger.kernel.org> # v3.10+
> Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Reviewed-by: Johan Hovold <jhovold@gmail.com>
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);
> }
^ permalink raw reply [flat|nested] 3+ messages in thread* [RESEND PATCH v4] ARM: at91: fix at91_sysirq_mask_rtc for sam9x5 SoCs
2014-05-09 14:51 ` Johan Hovold
@ 2014-05-09 15:00 ` Boris BREZILLON
0 siblings, 0 replies; 3+ messages in thread
From: Boris BREZILLON @ 2014-05-09 15:00 UTC (permalink / raw)
To: linux-arm-kernel
On 09/05/2014 16:51, Johan Hovold wrote:
> 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@linux-foundation.org>
>> Cc: <stable@vger.kernel.org> # v3.10+
>> Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
>> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
> Reviewed-by: Johan Hovold <jhovold@gmail.com>
>
> Looks good, but for the future: Why do you break the comment lines you
> added at column 60?
Oops, I guess I was influenced by the preceding lines (atmel's datasheet
quote).
>
> 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);
>> }
--
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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2014-05-09 14:43 [RESEND PATCH v4] ARM: at91: fix at91_sysirq_mask_rtc for sam9x5 SoCs Boris BREZILLON
2014-05-09 14:51 ` Johan Hovold
2014-05-09 15:00 ` Boris BREZILLON
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