From: Maxime Ripard <maxime.ripard@bootlin.com>
To: Chen-Yu Tsai <wens@csie.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>,
linux-mmc@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-sunxi@googlegroups.com,
Chris Blake <chrisrblake93@gmail.com>,
stable@vger.kernel.org
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 [thread overview]
Message-ID: <20190204093427.vg63e5xmd7u52leh@flea> (raw)
In-Reply-To: <20190203155628.16767-3-wens@csie.org>
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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: <stable@vger.kernel.org>
> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
>
> ---
>
> 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
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next prev parent reply other threads:[~2019-02-04 9:34 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 [this message]
2019-02-04 10:16 ` Chen-Yu Tsai
2019-02-04 13:41 ` Maxime Ripard
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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