Re: [PATCH 06/10] mci: rockchip-dwcmshc-sdhci: use ADMA2

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

On 5/11/26 4:01 PM, Sascha Hauer wrote:
> On 2026-05-11 14:55, Ahmad Fatoum wrote:
>> Hello Sascha,
>>
>> On 5/11/26 2:08 PM, Sascha Hauer wrote:
>>> The SDMA engine doesn't seem to be fast enough to keep up with HS400
>>> support. In preparation to add HS400 support to the driver switch to
>>> ADMA when available.
>>>
>>> Assisted-by: Claude Opus 4.7 <noreply@anthropic.com>
>>> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
>>> ---
>>>  drivers/mci/rockchip-dwcmshc-sdhci.c | 5 +++++
>>>  1 file changed, 5 insertions(+)
>>>
>>> diff --git a/drivers/mci/rockchip-dwcmshc-sdhci.c b/drivers/mci/rockchip-dwcmshc-sdhci.c
>>> index 04ee528f07..23c887e906 100644
>>> --- a/drivers/mci/rockchip-dwcmshc-sdhci.c
>>> +++ b/drivers/mci/rockchip-dwcmshc-sdhci.c
>>> @@ -361,6 +361,11 @@ static int rk_sdhci_probe(struct device *dev)
>>>  
>>>  	sdhci_setup_host(&host->sdhci);
>>>  
>>> +	ret = sdhci_setup_adma(&host->sdhci);
>>> +	if (ret && ret != -ENOTSUPP)
>>> +		dev_warn(dev, "ADMA setup failed (%pe), falling back to SDMA\n",
>>> +			 ERR_PTR(ret));
>>
>> As transparent fallback is implemented, could this be folded into
>> sdhci_setup_host, so it's opt-out instead of opt-in?
> 
> I don't expect much advantage from ADMA for drivers that do not need it.
> The advantage is that ADMA can do scatter gather DMA, but we don't make
> use of it in barebox.
> 
> I'd rather leave it opt-in for now at least for a few rounds.

Fair enough.

> 
> Sascha
> 
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