From 87f8887a4efe1942855c677b0b68fa847bf10312 Mon Sep 17 00:00:00 2001 From: Marek Szyprowski Date: Thu, 30 Nov 2017 13:14:51 +0100 Subject: [PATCH] clk: Manage proper runtime PM state in clk_change_rate() clk_change_rate() propagates rate change down to all its children. Such operation requires managing proper runtime PM state of each child, what was missing. Add needed calls to clk_pm_runtime*() to ensure that set_rate() clock callback is called on runtime active clock. This fixes following issue found on Exynos5433 TM2 board with devfreq enabled: Synchronous External Abort: synchronous external abort (0x96000210) at 0xffffff80093f5600 Internal error: : 96000210 [#1] PREEMPT SMP Modules linked in: CPU: 0 PID: 5 Comm: kworker/u16:0 Not tainted 4.15.0-rc1-next-20171129+ #4 Hardware name: Samsung TM2 board (DT) Workqueue: devfreq_wq devfreq_monitor task: ffffffc0ca96b600 task.stack: ffffff80093a8000 pstate: a0000085 (NzCv daIf -PAN -UAO) pc : clk_divider_set_rate+0x54/0x118 lr : clk_divider_set_rate+0x44/0x118 ... Process kworker/u16:0 (pid: 5, stack limit = 0xffffff80093a8000) Call trace: clk_divider_set_rate+0x54/0x118 clk_change_rate+0xfc/0x4e0 clk_change_rate+0x1f0/0x4e0 clk_change_rate+0x1f0/0x4e0 clk_change_rate+0x1f0/0x4e0 clk_core_set_rate_nolock+0x138/0x148 clk_set_rate+0x28/0x50 exynos_bus_passive_target+0x6c/0x11c update_devfreq_passive+0x58/0xb4 devfreq_passive_notifier_call+0x50/0x5c notifier_call_chain+0x4c/0x88 __srcu_notifier_call_chain+0x54/0x80 srcu_notifier_call_chain+0x14/0x1c update_devfreq+0x100/0x1b4 devfreq_monitor+0x2c/0x88 process_one_work+0x148/0x3d8 worker_thread+0x13c/0x3f8 kthread+0x100/0x12c ret_from_fork+0x10/0x18 Reported-by: Chanwoo Choi Fixes: 9a34b45397e5 ("clk: Add support for runtime PM") Signed-off-by: Marek Szyprowski Reviewed-by: Ulf Hansson Tested-by: Chanwoo Choi Reviewed-by: Chanwoo Choi Signed-off-by: Stephen Boyd --- drivers/clk/clk.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index c626127..06852d0a 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -1565,6 +1565,9 @@ static void clk_change_rate(struct clk_core *core) best_parent_rate = core->parent->rate; } + if (clk_pm_runtime_get(core)) + return; + if (core->flags & CLK_SET_RATE_UNGATE) { unsigned long flags; @@ -1635,6 +1638,8 @@ static void clk_change_rate(struct clk_core *core) /* handle the new child who might not be in core->children yet */ if (core->new_child) clk_change_rate(core->new_child); + + clk_pm_runtime_put(core); } static int clk_core_set_rate_nolock(struct clk_core *core, -- 2.7.4