linux-kernel - Re: [PATCH v3 6/7] mmc: sdhci_am654: Fix SDHCI_RESET

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Message-ID: <c677b825-012d-8f7f-2de9-16dd9363666c@gmail.com>
Date:   Tue, 25 Oct 2022 16:29:38 -0700
From:   Florian Fainelli <f.fainelli@...il.com>
To:     Brian Norris <briannorris@...omium.org>,
        Florian Fainelli <f.fainelli@...il.com>
Cc:     Adrian Hunter <adrian.hunter@...el.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Shawn Lin <shawn.lin@...k-chips.com>,
        linux-mmc@...r.kernel.org, Al Cooper <alcooperx@...il.com>,
        Bjorn Andersson <andersson@...nel.org>,
        Sowjanya Komatineni <skomatineni@...dia.com>,
        Broadcom internal kernel review list 
        <bcm-kernel-feedback-list@...adcom.com>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Konrad Dybcio <konrad.dybcio@...ainline.org>,
        NXP Linux Team <linux-imx@....com>,
        Thierry Reding <thierry.reding@...il.com>,
        Fabio Estevam <festevam@...il.com>,
        Michal Simek <michal.simek@...inx.com>,
        linux-kernel@...r.kernel.org, Shawn Guo <shawnguo@...nel.org>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        linux-arm-msm@...r.kernel.org, Haibo Chen <haibo.chen@....com>,
        Andy Gross <agross@...nel.org>,
        linux-arm-kernel@...ts.infradead.org,
        Faiz Abbas <faiz_abbas@...com>,
        Jonathan Hunter <jonathanh@...dia.com>
Subject: Re: [PATCH v3 6/7] mmc: sdhci_am654: Fix SDHCI_RESET_ALL for CQHCI

On 10/25/22 15:26, Brian Norris wrote:
> On Tue, Oct 25, 2022 at 02:53:46PM -0700, Florian Fainelli wrote:
>> On 10/25/22 14:45, Brian Norris wrote:
>>> On Tue, Oct 25, 2022 at 04:10:44PM +0300, Adrian Hunter wrote:
>>>> On 24/10/22 20:55, Brian Norris wrote:
>>>>> diff --git a/drivers/mmc/host/sdhci_am654.c b/drivers/mmc/host/sdhci_am654.c
>>>>> index 8f1023480e12..6a282c7a221e 100644
>>>>> --- a/drivers/mmc/host/sdhci_am654.c
>>>>> +++ b/drivers/mmc/host/sdhci_am654.c
>>>
>>>>> @@ -378,7 +379,7 @@ static void sdhci_am654_reset(struct sdhci_host *host, u8 mask)
>>>>>    	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
>>>>>    	struct sdhci_am654_data *sdhci_am654 = sdhci_pltfm_priv(pltfm_host);
>>>>> -	sdhci_reset(host, mask);
>>>>> +	sdhci_and_cqhci_reset(host, mask);
>>>>>    	if (sdhci_am654->quirks & SDHCI_AM654_QUIRK_FORCE_CDTEST) {
>>>>>    		ctrl = sdhci_readb(host, SDHCI_HOST_CONTROL);
>>>>
>>>> What about sdhci_reset in sdhci_am654_ops ?
>>>
>>> Oops, I think you caught a big fallacy in some of my patches: I assumed
>>> there was a single reset() implementation in a given driver (an unwise
>>> assumption, I realize). I see at least sdhci-brcmstb.c also has several
>>> variant ops that call sdhci_reset(), and I should probably convert them
>>> too.
>>
>> You got it right for sdhci-brcmstb.c because "supports-cqe" which gates the
>> enabling of CQE can only be found with the "brcm,bcm7216-sdhci" compatible
>> which implies using brcmstb_reset().
> 
> I don't see any in-tree device trees for these chips (which is OK), and
> that's not what the Documentation/ says, and AFAICT nothing in the
> driver is limiting other variants from specifying the "supports-cqe"
> flag in their (out-of-tree) device tree. The closest thing I see is that
> an *example* in brcm,sdhci-brcmstb.yaml shows "supports-cqe" only on
> brcm,bcm7216-sdhci -- but an example is not a binding agreement. Am I
> missing something?
> 
> Now of course, you probably know behind the scenes that there are no
> other sdhci-brcmstb-relevant controllers that "support cqe", but AFAICT
> I have no way of knowing that a priori. The driver and bindings give
> (too much?) flexibility.

Yes that is fair enough, I will amend the binding document to make it 
clearer that 'supports-cqe' only applies in case of "brcm,bcm7216-sdhci" 
and not for other compatibles.
-- 
Florian