linux-kernel - [PATCH v2] soc: mediatek: Check if power domains can be powered on at boot time

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Date:   Mon, 28 Sep 2020 11:31:35 +0800
From:   Nicolas Boichat <drinkcat@...omium.org>
To:     Matthias Brugger <matthias.bgg@...il.com>
Cc:     Nicolas Boichat <drinkcat@...omium.org>,
        Daniel Kurtz <djkurtz@...omium.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-mediatek@...ts.infradead.org
Subject: [PATCH v2] soc: mediatek: Check if power domains can be powered on at boot time

In the error case, where a power domain cannot be powered on
successfully at boot time (in mtk_register_power_domains),
pm_genpd_init would still be called with is_off=false, and the
system would later try to disable the power domain again, triggering
warnings as disabled clocks are disabled again (and other potential
issues).

Also print a warning splat in that case, as this should never
happen.

Fixes: c84e358718a66f7 ("soc: Mediatek: Add SCPSYS power domain driver")
Signed-off-by: Nicolas Boichat <drinkcat@...omium.org>
---

Changes in v2:
 - Add WARN_ON if the domain can't be powered on, to make it more
   obvious that this should not happen (there is already an error
   message).

 drivers/soc/mediatek/mtk-scpsys.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/soc/mediatek/mtk-scpsys.c b/drivers/soc/mediatek/mtk-scpsys.c
index f669d3754627..ca75b14931ec 100644
--- a/drivers/soc/mediatek/mtk-scpsys.c
+++ b/drivers/soc/mediatek/mtk-scpsys.c
@@ -524,6 +524,7 @@ static void mtk_register_power_domains(struct platform_device *pdev,
 	for (i = 0; i < num; i++) {
 		struct scp_domain *scpd = &scp->domains[i];
 		struct generic_pm_domain *genpd = &scpd->genpd;
+		bool on;
 
 		/*
 		 * Initially turn on all domains to make the domains usable
@@ -531,9 +532,9 @@ static void mtk_register_power_domains(struct platform_device *pdev,
 		 * software.  The unused domains will be switched off during
 		 * late_init time.
 		 */
-		genpd->power_on(genpd);
+		on = !WARN_ON(genpd->power_on(genpd) < 0);
 
-		pm_genpd_init(genpd, NULL, false);
+		pm_genpd_init(genpd, NULL, !on);
 	}
 
 	/*
-- 
2.28.0.681.g6f77f65b4e-goog