This is a note to let you know that I've just added the patch titled

    ARM: at91: fix at91_sysirq_mask_rtc for sam9x5 SoCs

to the 3.15-stable tree which can be found at:
    
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     arm-at91-fix-at91_sysirq_mask_rtc-for-sam9x5-socs.patch
and it can be found in the queue-3.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.


>From 9dcc87fec8947308e0111c65dcd881e6aa5b1673 Mon Sep 17 00:00:00 2001
From: Boris BREZILLON <[email protected]>
Date: Fri, 6 Jun 2014 14:36:11 -0700
Subject: ARM: at91: fix at91_sysirq_mask_rtc for sam9x5 SoCs

From: Boris BREZILLON <[email protected]>

commit 9dcc87fec8947308e0111c65dcd881e6aa5b1673 upstream.

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.

Signed-off-by: Boris BREZILLON <[email protected]>
Reported-by: Bryan Evenson <[email protected]>
Reviewed-by: Johan Hovold <[email protected]>
Acked-by: Nicolas Ferre <[email protected]>
Cc: Bryan Evenson <[email protected]>
Cc: Andrew Victor <[email protected]>
Cc: Jean-Christophe Plagniol-Villard <[email protected]>
Cc: Alessandro Zummo <[email protected]>
Cc: Mark Roszko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 arch/arm/mach-at91/sysirq_mask.c |   22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

--- 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);
 }


Patches currently in stable-queue which might be from 
[email protected] are

queue-3.15/arm-at91-fix-at91_sysirq_mask_rtc-for-sam9x5-socs.patch
queue-3.15/rtc-rtc-at91rm9200-fix-infinite-wait-for-ackupd-irq.patch
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