Re: [PATCH] hw/sd/sdhci: Set reset value of interrupt registers

[BALATON Zoltan <balaton@eik.bme.hu>]

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On Thu, 6 Feb 2025, Philippe Mathieu-Daudé wrote:
> On 15/1/25 20:04, BALATON Zoltan wrote:
>> The interrupt enable registers are not reset to 0 but some bits are
>> enabled on reset. At least some U-Boot versions seem to expect this
>> and not initialise these registers before expecting interrupts. The
>> numbers in this patch match what QorIQ P1022 has on reset and fix
>> U-Boot for this SoC and should not break other drivers that initialise
>> (and thus overwrite) these reset values.
>> 
>> Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
>> ---
>> I've also noticed that the work around marked with an XXX comment near
>> line 600 breaks the U-Boot I've tested so I need to disable it:
>> if ((s->sdmasysad % boundary_chk) == 0) {
>> -        page_aligned = true;
>> +//        page_aligned = true;
>> }
>> What should this hack fix and could it be now removed or somehow
>> restricted to cases where it's needed?
>
> Cc'ing Jamin for
> https://lore.kernel.org/qemu-devel/20241213031205.641009-2-jamin_lin@aspeedtech.com/
>
>> 
>> hw/sd/sdhci.c | 2 ++
>>   1 file changed, 2 insertions(+)
>> 
>> diff --git a/hw/sd/sdhci.c b/hw/sd/sdhci.c
>> index 58375483e3..88eb0bfcb2 100644
>> --- a/hw/sd/sdhci.c
>> +++ b/hw/sd/sdhci.c
>> @@ -303,6 +303,8 @@ static void sdhci_reset(SDHCIState *s)
>>       s->data_count = 0;
>>       s->stopped_state = sdhc_not_stopped;
>>       s->pending_insert_state = false;
>> +    s->norintstsen = 0x013f;
>> +    s->errintstsen = 0x117f;
>
> I guess the problem is earlier:
>
>    /*
>     * Set all registers to 0. Capabilities/Version registers are not cleared
>     * and assumed to always preserve their value, given to them during
>     * initialization
>     */
>    memset(&s->sdmasysad, 0, (uintptr_t)&s->capareg - 
> (uintptr_t)&s->sdmasysad);
>
> Not all registers have to be reset.

Nothing seems to program those registers before reset but the reset values 
are documented (for Freescale eSDHCI) to be the above so just not zeroing 
them does not seem to be enough. Bernhard has similar patch in his branch, 
not sure if he came up with that separately or took this one. Do you have 
some docs on which regs should not be reset?

Regards,
BALATON Zoltan