linux-kernel - [RFT PATCH] mmc: pwrseq_simple: Fix incorrect handling of GPIO bitmap

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Message-Id: <20181012190901.1243-1-jmkrzyszt@gmail.com>
Date:   Fri, 12 Oct 2018 21:09:01 +0200
From:   Janusz Krzysztofik <jmkrzyszt@...il.com>
To:     Ulf Hansson <ulf.hansson@...aro.org>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        linux-mmc@...r.kernel.org, linux-gpio@...r.kernel.org,
        Linux Samsung SOC <linux-samsung-soc@...r.kernel.org>,
        linux-kernel@...r.kernel.org, Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Fabio Estevam <fabio.estevam@....com>,
        NXP Linux Team <linux-imx@....com>,
        linux-arm-kernel@...ts.infradead.org,
        Kukjin Kim <kgene@...nel.org>,
        Benoît Cousson <bcousson@...libre.com>,
        Tony Lindgren <tony@...mide.com>,
        Enric Balletbo i Serra <eballetbo@...il.com>,
        Javier Martinez Canillas <javier@...hile0.org>,
        linux-omap@...r.kernel.org, Heiko Stuebner <heiko@...ech.de>,
        linux-rockchip@...ts.infradead.org,
        Carlo Caione <carlo@...one.org>,
        Kevin Hilman <khilman@...libre.com>,
        linux-amlogic@...ts.infradead.org,
        Janusz Krzysztofik <jmkrzyszt@...il.com>
Subject: [RFT PATCH] mmc: pwrseq_simple: Fix incorrect handling of GPIO bitmap

Commit b9762bebc633 ("gpiolib: Pass bitmaps, not integer arrays, to
get/set array") changed the way GPIO values are passed to
gpiod_get/set_array_value() and friends.  The new code introduced into
mmc_pwrseq_simple_set_gpios_value() incorrectly interpretes the 'value'
argument as a bitmap of GPIO values and assigns it directly to the
'values' bitmap variable passed to gpiod_set_array_value_cansleep()
instead of filling that bitmap with bits equal to the 'value' argument.
As a result, only member 0 of the array is handled correctly.

Moreover, wrong assumption is taken about the 'values' bitmap size not
exceding the number of bits of the 'value' argument type.

Fix it.

Signed-off-by: Janusz Krzysztofik <jmkrzyszt@...il.com>
---
Hi,

I think that patch has been missed while we were resolving issues 
related to GPIO fast bitmap processing.  Since all issues other than the 
one addreessed by this patch have been been hopefully identified and 
fixed, GPIO tree seems now to be in good shape in regard to that. 
However, I believe pwrseq_simple is still broken.  Hence, I'm 
resubmitting this patch to Ulf for inclusion in MMC tree, Cc: many other 
people who are kindly requested to test it if possible.

I've identified the following DT files representing devices which may be 
affected (have more than one GPIO assigned to pwrseq_simple):
- arch/arm/boot/dts/imx6qdl-sr-som-brcm.dtsi
- arch/arm/boot/dts/exynos5250-snow-common.dtsi
- arch/arm/boot/dts/imx6sl-warp.dts
- arch/arm/boot/dts/omap3-igep0030.dts
- arch/arm/boot/dts/omap3-igep0020.dts
- arch/arm/boot/dts/rk3036-kylin.dts
- arch/arm64/boot/dts/rockchip/rk3368-r88.dts
- arch/arm64/boot/dts/amlogic/meson-gxbb-vega-s95.dtsi

Please start with checking if pwrseq_simple from linux-next works for 
you and if not, please test if this patch fixes the issue.

Thanks,
Janusz

 drivers/mmc/core/pwrseq_simple.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/core/pwrseq_simple.c b/drivers/mmc/core/pwrseq_simple.c
index 7f882a2bb872..ece34c734693 100644
--- a/drivers/mmc/core/pwrseq_simple.c
+++ b/drivers/mmc/core/pwrseq_simple.c
@@ -40,13 +40,22 @@ static void mmc_pwrseq_simple_set_gpios_value(struct mmc_pwrseq_simple *pwrseq,
 	struct gpio_descs *reset_gpios = pwrseq->reset_gpios;

 	if (!IS_ERR(reset_gpios)) {
-		DECLARE_BITMAP(values, BITS_PER_TYPE(value));
+		unsigned long *values;
 		int nvalues = reset_gpios->ndescs;

-		values[0] = value;
+		values = bitmap_alloc(nvalues, GFP_KERNEL);
+		if (!values)
+			return;
+
+		if (value)
+			bitmap_fill(values, nvalues);
+		else
+			bitmap_zero(values, nvalues);

 		gpiod_set_array_value_cansleep(nvalues, reset_gpios->desc,
 					       reset_gpios->info, values);
+
+		kfree(values);
 	}
 }

-- 
2.16.4