linux-kernel - [PATCH] clk: Don't try to enable critical clocks if prepare failed

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Message-Id: <20191225163429.29694-1-linux@roeck-us.net>
Date:   Wed, 25 Dec 2019 08:34:29 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Michael Turquette <mturquette@...libre.com>
Cc:     Stephen Boyd <sboyd@...nel.org>, linux-clk@...r.kernel.org,
        linux-kernel@...r.kernel.org, Guenter Roeck <linux@...ck-us.net>,
        Jerome Brunet <jbrunet@...libre.com>
Subject: [PATCH] clk: Don't try to enable critical clocks if prepare failed

The following traceback is seen if a critical clock fails to prepare.

bcm2835-clk 3f101000.cprman: plld: couldn't lock PLL
------------[ cut here ]------------
Enabling unprepared plld_per
WARNING: CPU: 1 PID: 1 at drivers/clk/clk.c:1014 clk_core_enable+0xcc/0x2c0
...
Call trace:
 clk_core_enable+0xcc/0x2c0
 __clk_register+0x5c4/0x788
 devm_clk_hw_register+0x4c/0xb0
 bcm2835_register_pll_divider+0xc0/0x150
 bcm2835_clk_probe+0x134/0x1e8
 platform_drv_probe+0x50/0xa0
 really_probe+0xd4/0x308
 driver_probe_device+0x54/0xe8
 device_driver_attach+0x6c/0x78
 __driver_attach+0x54/0xd8
...

Check return values from clk_core_prepare() and clk_core_enable() and
bail out if any of those functions returns an error.

Cc: Jerome Brunet <jbrunet@...libre.com>
Fixes: 99652a469df1 ("clk: migrate the count of orphaned clocks at init")
Signed-off-by: Guenter Roeck <linux@...ck-us.net>
---
 drivers/clk/clk.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 6a11239ccde3..772258de2d1f 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -3426,11 +3426,17 @@ static int __clk_core_init(struct clk_core *core)
 	if (core->flags & CLK_IS_CRITICAL) {
 		unsigned long flags;
 
-		clk_core_prepare(core);
+		ret = clk_core_prepare(core);
+		if (ret)
+			goto out;
 
 		flags = clk_enable_lock();
-		clk_core_enable(core);
+		ret = clk_core_enable(core);
 		clk_enable_unlock(flags);
+		if (ret) {
+			clk_core_unprepare(core);
+			goto out;
+		}
 	}
 
 	clk_core_reparent_orphans_nolock();
-- 
2.17.1