If of_genpd_add_provider_onecell() fails the following kernel crash is
observed on a kernel built with multi_v7_defconfig:
[ 1.739301] [00000040] *pgd=00000000
[ 1.739310] Internal error: Oops: 5 [#1] SMP ARM
[ 1.739319] Modules linked in:
[ 1.739328] CPU: 1 PID: 95 Comm: kworker/1:4 Not tainted 4.8.0-11897-g6b5e09a #1
[ 1.739331] Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
[ 1.739352] Workqueue: pm genpd_power_off_work_fn
[ 1.739356] task: ee63d400 task.stack: ee70a000
[ 1.739365] PC is at mutex_lock+0xc/0x4c
[ 1.739374] LR is at regulator_disable+0x2c/0x60
[ 1.739379] pc : [<c0bc0da0>] lr : [<c06e4b10>] psr: 60000013
[ 1.739379] sp : ee70beb0 ip : 10624dd3 fp : ee6e6280
[ 1.739382] r10: eefb0900 r9 : 00000000 r8 : c1309918
[ 1.739385] r7 : 00000000 r6 : 00000040 r5 : 00000000 r4 : 00000040
[ 1.739390] r3 : 0000004c r2 : 7fffd540 r1 : 000001e4 r0 : 00000040
Instead of returning of_genpd_add_provider_onecell() directly,
we should check its return value and in the case of error we
should unwind the previously taken actions, which in these case are:
- Call imx6q_pm_pu_power_off()
- Set imx6q_pu_domain.reg back to NULL
Setting imx6q_pu_domain.reg to NULL in the error case is important
as it will prevent further operations in the pu_reg regulator.
This kernel crash is not observed with imx_v6_v7_defconfig because
it selects GPU and VPU drivers, which are consumers of the GPC block
and thus change the refcount of the pu_reg regulator.
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
f9d1f7a7ad