Re: [PATCH] hw/sd/sdhci: Do not force sdhci_mmio_*_ops onto all SD controllers

[Bernhard Beschow]

Am 10. Juli 2023 16:01:46 UTC schrieb Bernhard Beschow <shentey@gmail.com>:
>
>
>Am 10. Juli 2023 10:16:35 UTC schrieb "Philippe Mathieu-Daudé" 
><philmd@linaro.org>:
>>On 9/7/23 10:09, Bernhard Beschow wrote:
>>> Since commit c0a55a0c9da2 "hw/sd/sdhci: Support big endian SD host 
>>> controller
>>> interfaces" sdhci_common_realize() forces all SD card controllers to use 
>>> either
>>> sdhci_mmio_le_ops or sdhci_mmio_be_ops, depending on the "endianness" 
>>> property.
>>> However, there are device models which use different MMIO ops: 
>>> TYPE_IMX_USDHC
>>> uses usdhc_mmio_ops and TYPE_S3C_SDHCI uses sdhci_s3c_mmio_ops.
>>> 
>>> Forcing sdhci_mmio_le_ops breaks SD card handling on the "sabrelite" board, 
>>> for
>>> example. Fix this by defaulting the io_ops to little endian and switch to 
>>> big
>>> endian in sdhci_common_realize() only if there is a matchig big endian 
>>> variant
>>> available.
>>> 
>>> Fixes: c0a55a0c9da2 ("hw/sd/sdhci: Support big endian SD host controller
>>> interfaces")
>>> 
>>> Signed-off-by: Bernhard Beschow <shentey@gmail.com>
>>> ---
>>>   hw/sd/sdhci.c | 8 +++++++-
>>>   1 file changed, 7 insertions(+), 1 deletion(-)
>>> 
>>> diff --git a/hw/sd/sdhci.c b/hw/sd/sdhci.c
>>> index 6811f0f1a8..362c2c86aa 100644
>>> --- a/hw/sd/sdhci.c
>>> +++ b/hw/sd/sdhci.c
>>> @@ -1382,6 +1382,8 @@ void sdhci_initfn(SDHCIState *s)
>>>         s->insert_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, 
>>> sdhci_raise_insertion_irq, s);
>>>       s->transfer_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, 
>>> sdhci_data_transfer, s);
>>> +
>>> +    s->io_ops = &sdhci_mmio_le_ops;
>>>   }
>>>     void sdhci_uninitfn(SDHCIState *s)
>>> @@ -1399,9 +1401,13 @@ void sdhci_common_realize(SDHCIState *s, Error 
>>> **errp)
>>>   
>>
>>What about simply keeping the same code guarded with 'if (!s->io_ops)'?
>
>I chose below approach since it provides an error message when one attempts to 
>set one of the other device models to BE rather than just silently ignoring it.
>
>Also, I didn't want to make the assumption that `s->io_ops == NULL` implied 
>that sdhci_mmio_*_ops is needed. That's similar material the bug fixed is made 
>of, so I wanted to prevent that in the first place by being more explicit.
>
>In combination with the new error message the limitations of the current code 
>become hopefully very apparent now, and at the same time should provide enough 
>hints for adding BE support to the other device models if ever needed.
>
>Best regards,
>Bernhard

Ping

+ qemu--stable

>
>>
>>>       switch (s->endianness) {
>>>       case DEVICE_LITTLE_ENDIAN:
>>> -        s->io_ops = &sdhci_mmio_le_ops;
>>> +        /* s->io_ops is little endian by default */
>>>           break;
>>>       case DEVICE_BIG_ENDIAN:
>>> +        if (s->io_ops != &sdhci_mmio_le_ops) {
>>> +            error_setg(errp, "SD controller doesn't support big 
>>> endianness");
>>> +            return;
>>> +        }
>>>           s->io_ops = &sdhci_mmio_be_ops;
>>>           break;
>>>       default:
>>