From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Ripard Subject: Re: [PATCH 2/3] mmc: sunxi: Filter out unsupported modes declared in the device tree Date: Mon, 4 Feb 2019 10:34:27 +0100 Message-ID: <20190204093427.vg63e5xmd7u52leh@flea> References: <20190203155628.16767-1-wens@csie.org> <20190203155628.16767-3-wens@csie.org> Reply-To: maxime.ripard-LDxbnhwyfcJBDgjK7y7TUQ@public.gmane.org Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="p42mp7wsvouznbye" Return-path: Sender: linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org Content-Disposition: inline In-Reply-To: <20190203155628.16767-3-wens-jdAy2FN1RRM@public.gmane.org> List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , To: Chen-Yu Tsai Cc: Ulf Hansson , linux-mmc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org, Chris Blake , stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: devicetree@vger.kernel.org --p42mp7wsvouznbye Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline 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: > Signed-off-by: Chen-Yu Tsai > > --- > > 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 > + /* TODO: This driver doesn't support HS200 and HS400 modes yet */ > + mmc->caps2 &= ~(MMC_CAP2_HS200 | MMC_CAP2_HS400); And HS200 works too. Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com --p42mp7wsvouznbye--