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

[Seungwon Jeon <tgih.jun@samsung.com>]

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.

Thanks,
Seungwon Jeon
> 
> Thanks.
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