linux-kernel - [PATCH] mmc: pwrseq: Use highest priority for eMMC restart handler

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Date:	Wed, 21 Oct 2015 17:15:40 +0200
From:	Javier Martinez Canillas <javier@....samsung.com>
To:	linux-kernel@...r.kernel.org
Cc:	Markus Reichl <m.reichl@...etechno.de>,
	Anand Moon <linux.amoon@...il.com>,
	linux-samsung-soc@...r.kernel.org,
	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	Alim Akhtar <alim.akhtar@...sung.com>,
	Javier Martinez Canillas <javier@....samsung.com>,
	Marek Szyprowski <m.szyprowski@...sung.com>,
	linux-mmc@...r.kernel.org, Alexandre Courbot <acourbot@...dia.com>,
	Ulf Hansson <ulf.hansson@...aro.org>
Subject: [PATCH] mmc: pwrseq: Use highest priority for eMMC restart handler

The pwrseq_emmc driver does a eMMC card reset before a system reboot to
allow broken or limited ROM boot-loaders (that don't have an eMMC reset
logic) to be able to read the second stage from the eMMC.

But this has to be called before a system reboot handler and while most
of them use the priority 128, there are other restart handlers (such as
the syscon-reboot one) that use a higher priority. So, use the highest
priority to make sure that the eMMC hw is reset before a system reboot.

Signed-off-by: Javier Martinez Canillas <javier@....samsung.com>
Tested-by: Markus Reichl <m.reichl@...etechno.de>
Tested-by: Anand Moon <linux.amoon@...il.com>
Reviewed-by: Alim Akhtar <alim.akhtar@...sung.com>

---
Hello,

This patch was needed since a recent series from Alim [0] added
syscon reboot and poweroff support to Exynos SoCs and removed
the reset handler in the Exynos Power Management Unit (PMU) code.

But the PMU and syscon-reboot restart handler have a different
priority so [0] breaks restart when eMMC is used on these boards.

[0]: http://www.spinics.net/lists/arm-kernel/msg454396.html

So this patch must be merged before [0] to avoid regressions.

Best regards,
Javier

 drivers/mmc/core/pwrseq_emmc.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/mmc/core/pwrseq_emmc.c b/drivers/mmc/core/pwrseq_emmc.c
index 137c97fb7aa8..ad4f94ec7e8d 100644
--- a/drivers/mmc/core/pwrseq_emmc.c
+++ b/drivers/mmc/core/pwrseq_emmc.c
@@ -84,11 +84,11 @@ struct mmc_pwrseq *mmc_pwrseq_emmc_alloc(struct mmc_host *host,
 
 	/*
 	 * register reset handler to ensure emmc reset also from
-	 * emergency_reboot(), priority 129 schedules it just before
-	 * system reboot
+	 * emergency_reboot(), priority 255 is the highest priority
+	 * so it will be executed before any system reboot handler.
 	 */
 	pwrseq->reset_nb.notifier_call = mmc_pwrseq_emmc_reset_nb;
-	pwrseq->reset_nb.priority = 129;
+	pwrseq->reset_nb.priority = 255;
 	register_restart_handler(&pwrseq->reset_nb);
 
 	pwrseq->pwrseq.ops = &mmc_pwrseq_emmc_ops;
-- 
2.4.3

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