From: Maxime Ripard <email@example.com> To: Chen-Yu Tsai <firstname.lastname@example.org> Cc: Ulf Hansson <email@example.com>, firstname.lastname@example.org, linux-arm-kernel <email@example.com>, devicetree <firstname.lastname@example.org>, linux-kernel <email@example.com>, linux-sunxi <firstname.lastname@example.org>, Chris Blake <email@example.com>, stable <firstname.lastname@example.org> Subject: Re: [PATCH 2/3] mmc: sunxi: Filter out unsupported modes declared in the device tree Date: Mon, 4 Feb 2019 14:41:10 +0100 [thread overview] Message-ID: <20190204134110.dvo3qvnhiksqig2l@flea> (raw) In-Reply-To: <CAGb2v64-3Cs_RaO4erAr96JStEUzZ7ZRDjAYYjK2QsWfxusKxQ@mail.gmail.com> [-- Attachment #1: Type: text/plain, Size: 3157 bytes --] On Mon, Feb 04, 2019 at 06:16:24PM +0800, Chen-Yu Tsai wrote: > On Mon, Feb 4, 2019 at 5:34 PM Maxime Ripard <email@example.com> wrote: > > > > On Sun, Feb 03, 2019 at 11:56:27PM +0800, Chen-Yu Tsai wrote: > > > The MMC device tree bindings include properties used to signal various > > > signalling speed modes. Until now the sunxi driver was accepting them > > > without any further filtering, while the sunxi device trees were not > > > actually using them. > > > > > > Since some of the H5 boards can not run at higher speed modes stably, > > > we are resorting to declaring the higher speed modes per-board. > > > > > > Regardless, having boards declare modes and blindly following them, > > > even without proper support in the driver, is generally a bad thing. > > > > > > Filter out all unsupported modes from the capabilities mask after > > > the device tree properties have been parsed. > > > > > > Cc: <firstname.lastname@example.org> > > > Signed-off-by: Chen-Yu Tsai <email@example.com> > > > > > > --- > > > > > > This should be backported to stable kernels in case people try to run > > > new device trees (that declare newly supported modes) with old kernels. > > > --- > > > drivers/mmc/host/sunxi-mmc.c | 16 ++++++++++++++++ > > > 1 file changed, 16 insertions(+) > > > > > > diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c > > > index 7415af8c8ff6..a01433012db0 100644 > > > --- a/drivers/mmc/host/sunxi-mmc.c > > > +++ b/drivers/mmc/host/sunxi-mmc.c > > > @@ -1415,6 +1415,22 @@ static int sunxi_mmc_probe(struct platform_device *pdev) > > > if (ret) > > > goto error_free_dma; > > > > > > + /* > > > + * If we don't support delay chains in the SoC, we can't use any > > > + * of the DDR speed modes. Mask them out in case the device > > > + * tree specifies the properties for them, which gets added to > > > + * the caps by mmc_of_parse() above. > > > + */ > > > + if (!(host->cfg->clk_delays || host->use_new_timings)) > > > + mmc->caps &= ~(MMC_CAP_3_3V_DDR | MMC_CAP_1_8V_DDR | > > > + MMC_CAP_1_2V_DDR); > > > + > > > + /* TODO: UHS modes untested due to lack of supporting boards */ > > > + mmc->caps &= ~MMC_CAP_UHS; > > > > I've tested up to SDR104 and it works on the A64 at least > > That's good to know. What board was this on? I had given up hope waiting > for a vendor to produce a board that could do proper voltage switching for > SD cards. On a Sootech SoM, that had an HS400 eMMC and an SDR104 Marvell WiFi chip. I don't have that board anymore, and the website seems down now though :/ > > > + /* TODO: This driver doesn't support HS200 and HS400 modes yet */ > > > + mmc->caps2 &= ~(MMC_CAP2_HS200 | MMC_CAP2_HS400); > > > > And HS200 works too. > > OK. I thought there was some special magic required in the driver. Maybe > that was for HS400 only? Again, what board was this on? Yeah, that was for HS400 only Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 228 bytes --]
next prev parent reply other threads:[~2019-02-04 13:41 UTC|newest] Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-02-03 15:56 mmc: sunxi: Fix eMMC usage on H5 boards Chen-Yu Tsai 2019-02-03 15:56 ` [PATCH 1/3] mmc: sunxi: Disable HS-DDR mode for H5 eMMC controller by default Chen-Yu Tsai 2019-02-04 9:32 ` Maxime Ripard 2019-02-03 15:56 ` [PATCH 2/3] mmc: sunxi: Filter out unsupported modes declared in the device tree Chen-Yu Tsai 2019-02-04 9:34 ` Maxime Ripard 2019-02-04 10:16 ` Chen-Yu Tsai 2019-02-04 13:41 ` Maxime Ripard [this message] 2019-02-05 8:42 ` Chen-Yu Tsai 2019-02-05 9:51 ` Maxime Ripard 2019-02-03 15:56 ` [PATCH 3/3] arm64: dts: allwinner: h5: libretech-all-h3-cc: Mark eMMC HS-DDR 3.3V capable Chen-Yu Tsai 2019-02-03 15:59 ` [PATCH 0/3] mmc: sunxi: Fix eMMC usage on H5 boards Chen-Yu Tsai
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