From mboxrd@z Thu Jan  1 00:00:00 1970
From: santosh.shilimkar@oracle.com (santosh shilimkar)
Date: Mon, 22 Jun 2015 14:23:10 -0700
Subject: [PATCH] ARM: keystone: ecc: add ddr3 ecc interrupt handling
In-Reply-To: <55887521.7010708@ti.com>
References: <1434654589-28157-1-git-send-email-vitalya@ti.com>
 <558436C1.3050402@oracle.com> <55887521.7010708@ti.com>
Message-ID: <55887CBE.8040504@oracle.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org


On 6/22/2015 1:50 PM, Murali Karicheri wrote:
> On 06/19/2015 11:35 AM, santosh shilimkar wrote:
>> On 6/18/2015 12:09 PM, Vitaly Andrianov wrote:
>>> This patch adds ARM L1/L2 ECC handler support and DDR3 ECC interrupt
>>> handling for Keystone II devices, the kernel will reboot if the error
>>> is 2-bit error for DDR ECC or L1/L2 ECC error.
>>>
>>> Signed-off-by: Hao Zhang <hzhang@ti.com>
>>> Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
>>> Signed-off-by: Vitaly Andrianov <vitalya@ti.com>
>>> ---
>>>   arch/arm/mach-keystone/Makefile       |  2 +-
>>>   arch/arm/mach-keystone/keystone.c     | 63 ++++++++++++++++++++++++--
>>>   arch/arm/mach-keystone/keystone.h     |  1 +
>>>   arch/arm/mach-keystone/keystone_ecc.c | 85
>>> +++++++++++++++++++++++++++++++++++
>>>   arch/arm/mach-keystone/platsmp.c      |  3 +-
>>>   5 files changed, 148 insertions(+), 6 deletions(-)
>>>   create mode 100644 arch/arm/mach-keystone/keystone_ecc.c
>>>
>
>>>
>>> @@ -49,6 +54,56 @@ static int keystone_platform_notifier(struct
>>> notifier_block *nb,
>>>       return NOTIFY_OK;
>>>   }
>>>
>> +RMK. Would like to know if he wish to have below code in
>> generic ARM code
>>
>>> +#define L2_INTERN_ASYNC_ERROR  BIT(30)
>>> +
>>> +static irqreturn_t arm_l1l2_ecc_err_irq_handler(int irq, void
>>> *reg_virt)
>>> +{
>>> +    int ret = IRQ_NONE;
>>> +    u32 status, fault;
>>> +
>>> +    /* read and clear L2ECTLR CP15 register for L2 ECC error */
>>> +    asm("mrc p15, 1, %0, c9, c0, 3" : "=r"(status));
>>> +
>>> +    if (status & L2_INTERN_ASYNC_ERROR) {
>>> +        status &= ~L2_INTERN_ASYNC_ERROR;
>>> +        asm("mcr p15, 1, %0, c9, c0, 3" : : "r" (status));
>>> +        asm("mcr p15, 0, %0, c5, c1, 0" : "=r" (fault));
>>> +        /*
>>> +         * Do a machine restart as this is double bit ECC error
>>> +         * that can't be corrected
>>> +         */
>>> +        pr_err("ARM Cortex A15 L1/L2 ECC error, CP15 ADFSR 0x%x\n",
>>> +               fault);
>>> +        machine_restart(NULL);
>>> +        ret = IRQ_HANDLED;
>>> +    }
>>> +    return ret;
>> So your non-double bit errors even though handled returns as IRQ_NONE.
>
> looking at the A15 TRM, I see only single and double bit errors
> are documented. There is no discussion about more than 2 bit errors.
> Single bit errors don't raise an interrupt. So only case this gets
> called should be for double bit which is handled. So just log an error
> message as below and return IRQ_HANDLED?
>
> pr_err("Unexpected ARM Cortex A15 L1/L2 multi bit error");
>
Sounds ok.