Re: [PATCH] mmc: dw_mmc: clear INSTS register when initialize

Jaehoon Chung
2013-04-26T05:18:42Z

On 04/26/2013 01:24 PM, Seungwon Jeon wrote:
> On Thursday, April 25, 2013, Joonyoung Shim wrote:
>> On 04/25/2013 09:45 AM, Jaehoon Chung wrote:
>>> On 04/24/2013 12:05 PM, Joonyoung Shim wrote:
>>>> On 04/24/2013 10:34 AM, Seungwon Jeon wrote:
>>>>> On Tuesday, April 23, 2013, Jaehoon Chung wrote:
>>>>>> On 04/23/2013 06:57 PM, Seungwon Jeon wrote:
>>>>>>> Hi,
>>>>>>>
>>>>>>> On Thursday, April 18, 2013, Joonyoung Shim wrote:
>>>>>>>> If pending interrupt for IDMAC exists when probe, it will call interrupt
>>>>>>>> handler unnecessarily.
>>>>>>>>
>>>>>>>> Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
>>>>>>>> ---
>>>>>>>> drivers/mmc/host/dw_mmc.c | 3 +++
>>>>>>>> 1 file changed, 3 insertions(+)
>>>>>>>>
>>>>>>>> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
>>>>>>>> index 323c502..b0057a2 100644
>>>>>>>> --- a/drivers/mmc/host/dw_mmc.c
>>>>>>>> +++ b/drivers/mmc/host/dw_mmc.c
>>>>>>>> @@ -2192,6 +2192,7 @@ int dw_mci_probe(struct dw_mci *host)
>>>>>>>>
>>>>>>>> /* Clear the interrupts for the host controller */
>>>>>>>> mci_writel(host, RINTSTS, 0xFFFFFFFF);
>>>>>>>> + mci_writel(host, IDSTS, 0xFFFFFFFF);
>>>>>>> 0x337 is correct for bits. Could you check the bit filed?
>>>> I feel it's better to use already existing defines than 0x337.
>>>>
>>>>>> I think that don't care which reset value used.
>>>>>> "It is recommended that you write 0xffff_ffff to the Raw Interrupt register @0x044 and IDSTS
>> @0x8C
>>>>>> in order to clear any pending interrupts before setting the int_enable bit."
>>>>>> This boot mode case is also used the 0xffff_ffff.
>>>> Jaehoon, can i get this sentence from which document?
>>> That comment is existed at "Synopsys DesignWare Cores mobile storage host databook".
>>> So we can use the 0xffff_ffff.
>>>
>>> Best Regards,
>>> Jaehoon Chung
>>>>> In case IDSTS all 32bit are not for interrupt status unlike RINTSTS.
>>>>> IDSTS[31:17] is reserved and IDSTS[16:0] also contains 'reserved' and 'read-only' field.
>>>>> Correct use would be needed.
>>
>> I know, but as Jaehoon said, it recommands to write 0xFFFFFFFF "Synopsys
>> DesignWare Cores mobile storage host databook" document, so i also think
>> it's ok.
>>
>> Nevertheless if you want to use strict bits set, i can modify it. What
>> is your idea?
> Jaehoon,
> Thank you for information. I also checked that description,
> but I still feel it doesn't make sense a little bit.
> It seems that manual mentions both RINTSTS and IDSTS at a time while focusing the RINTSTS.
> In a general approach, it's expected to touch relevant fields.
Dear Seungwon,

I don't mind which reset value is used. Then we can use the define macro like IDSTS_RESET_VALUE.
It's important that reset the IDSTS register to prevent pending interrupt.

Best Regards,
Jaehoon Chung
>
> Thanks,
> Seungwon Jeon
>>
>> Thanks.
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