Re: [REGRESSION] sdhci no longer detects SD cards on LX2160A - Russell King

From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: Fabio Estevam <festevam@gmail.com>
Cc: dann frazier <dann.frazier@canonical.com>,
	linux-mmc <linux-mmc@vger.kernel.org>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Will Deacon <will.deacon@arm.com>,
	Nicolin Chen <nicoleotsuka@gmail.com>,
	Christoph Hellwig <hch@lst.de>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [REGRESSION] sdhci no longer detects SD cards on LX2160A
Date: Tue, 17 Sep 2019 14:33:17 +0100	[thread overview]
Message-ID: <20190917133317.GQ25745@shell.armlinux.org.uk> (raw)
In-Reply-To: <CAOMZO5DXv8g5qTGdvobDdLWim+tW=vK4+K=P-VqJK23KERMhJw@mail.gmail.com>

On Tue, Sep 17, 2019 at 10:24:57AM -0300, Fabio Estevam wrote:
> Hi Russell,
> 
> On Tue, Sep 17, 2019 at 10:10 AM Russell King - ARM Linux admin
> <linux@armlinux.org.uk> wrote:
> 
> > Will suggested reverting bd2e75633c80 ("dma-contiguous: use fallback
> > alloc_pages for single pages") which has been implicated in the same
> > problem here:
> >
> > https://www.spinics.net/lists/arm-kernel/msg750623.html
> 
> It seems that the final fix was:
> https://lore.kernel.org/patchwork/patch/1121600/
> 
> Does it work for you if we follow the same idea?
> 
> --- a/drivers/mmc/host/sdhci-of-esdhc.c
> +++ b/drivers/mmc/host/sdhci-of-esdhc.c
> @@ -1105,6 +1105,7 @@ static int sdhci_esdhc_probe(struct platform_device *pdev)
> 
>         esdhc_init(pdev, host);
> 
> +       sdhci_enable_v4_mode(host);
>         sdhci_get_of_property(pdev);
> 
>         pltfm_host = sdhci_priv(host);

That attempts to set bit 12 of the host control register 2 (0x3e).
The LX2160A documentation states that bit 28 of 0x3c (they're 32-bit
wide registers there) is "reserved".

So, you're asking for a documented reserved bit to be set...

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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