From: Marek Szyprowski <m.szyprowski@samsung.com> To: linux-clk@vger.kernel.org, linux-pm@vger.kernel.org, linux-samsung-soc@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Marek Szyprowski <m.szyprowski@samsung.com>, Stephen Boyd <sboyd@codeaurora.org>, Michael Turquette <mturquette@baylibre.com>, Ulf Hansson <ulf.hansson@linaro.org>, Sylwester Nawrocki <s.nawrocki@samsung.com>, Chanwoo Choi <cw00.choi@samsung.com>, Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Subject: [PATCH] clk: Manage proper runtime PM state in clk_change_rate() Date: Thu, 30 Nov 2017 13:14:51 +0100 [thread overview] Message-ID: <20171130121451.6710-1-m.szyprowski@samsung.com> (raw) In-Reply-To: CGME20171130121511eucas1p1832c1f6e5bc9e263860e40478efca132@eucas1p1.samsung.com 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 <cw00.choi@samsung.com> Fixes: 9a34b45397e5 ("clk: Add support for runtime PM") Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> --- For some unknown reason handling of this case was missing in the initial patch, which added runtime PM support for clock core. Even tests in linux-next did not revealed this issue. This patch finaly fixes it, as it is now easy to trigger it with v4.15-rc1. Best regards Marek Szyprowski Samsung R&D Institute Poland --- drivers/clk/clk.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 647d056df88c..8a1860a36c77 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -1564,6 +1564,9 @@ 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; @@ -1634,6 +1637,8 @@ 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, -- 2.15.0
WARNING: multiple messages have this Message-ID (diff)
From: m.szyprowski@samsung.com (Marek Szyprowski) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH] clk: Manage proper runtime PM state in clk_change_rate() Date: Thu, 30 Nov 2017 13:14:51 +0100 [thread overview] Message-ID: <20171130121451.6710-1-m.szyprowski@samsung.com> (raw) In-Reply-To: CGME20171130121511eucas1p1832c1f6e5bc9e263860e40478efca132@eucas1p1.samsung.com 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 <cw00.choi@samsung.com> Fixes: 9a34b45397e5 ("clk: Add support for runtime PM") Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> --- For some unknown reason handling of this case was missing in the initial patch, which added runtime PM support for clock core. Even tests in linux-next did not revealed this issue. This patch finaly fixes it, as it is now easy to trigger it with v4.15-rc1. Best regards Marek Szyprowski Samsung R&D Institute Poland --- drivers/clk/clk.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 647d056df88c..8a1860a36c77 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -1564,6 +1564,9 @@ 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; @@ -1634,6 +1637,8 @@ 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, -- 2.15.0
next parent reply other threads:[~2017-11-30 12:14 UTC|newest] Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <CGME20171130121511eucas1p1832c1f6e5bc9e263860e40478efca132@eucas1p1.samsung.com> 2017-11-30 12:14 ` Marek Szyprowski [this message] 2017-11-30 12:14 ` [PATCH] clk: Manage proper runtime PM state in clk_change_rate() Marek Szyprowski 2017-11-30 13:24 ` Ulf Hansson 2017-11-30 13:24 ` Ulf Hansson 2017-12-01 1:41 ` Chanwoo Choi 2017-12-01 1:41 ` Chanwoo Choi 2017-12-05 23:26 ` Stephen Boyd 2017-12-05 23:26 ` Stephen Boyd
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