| Message ID | 20240312115249.3341654-1-treapking@chromium.org (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Headers | show |
| Series | [v4] clk: mediatek: Do a runtime PM get on controllers during probe | expand |
Il 12/03/24 12:51, Pin-yen Lin ha scritto: > mt8183-mfgcfg has a mutual dependency with genpd during the probing > stage, which leads to a deadlock in the following call stack: > > CPU0: genpd_lock --> clk_prepare_lock > genpd_power_off_work_fn() > genpd_lock() > generic_pm_domain::power_off() > clk_unprepare() > clk_prepare_lock() > > CPU1: clk_prepare_lock --> genpd_lock > clk_register() > __clk_core_init() > clk_prepare_lock() > clk_pm_runtime_get() > genpd_lock() > > Do a runtime PM get at the probe function to make sure clk_register() > won't acquire the genpd lock. Instead of only modifying mt8183-mfgcfg, > do this on all mediatek clock controller probings because we don't > believe this would cause any regression. > > Verified on MT8183 and MT8192 Chromebooks. > > Fixes: acddfc2c261b ("clk: mediatek: Add MT8183 clock support") > Signed-off-by: Pin-yen Lin <treapking@chromium.org> > MT8195 Cherry Tomato - no issues as well. Tested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Quoting Pin-yen Lin (2024-03-12 04:51:55) > mt8183-mfgcfg has a mutual dependency with genpd during the probing > stage, which leads to a deadlock in the following call stack: > > CPU0: genpd_lock --> clk_prepare_lock > genpd_power_off_work_fn() > genpd_lock() > generic_pm_domain::power_off() > clk_unprepare() > clk_prepare_lock() > > CPU1: clk_prepare_lock --> genpd_lock > clk_register() > __clk_core_init() > clk_prepare_lock() > clk_pm_runtime_get() > genpd_lock() > > Do a runtime PM get at the probe function to make sure clk_register() > won't acquire the genpd lock. Instead of only modifying mt8183-mfgcfg, > do this on all mediatek clock controller probings because we don't > believe this would cause any regression. > > Verified on MT8183 and MT8192 Chromebooks. > > Fixes: acddfc2c261b ("clk: mediatek: Add MT8183 clock support") > Signed-off-by: Pin-yen Lin <treapking@chromium.org> > > --- Applied to clk-fixes
diff --git a/drivers/clk/mediatek/clk-mtk.c b/drivers/clk/mediatek/clk-mtk.c index 2e55368dc4d8..bd37ab4d1a9b 100644 --- a/drivers/clk/mediatek/clk-mtk.c +++ b/drivers/clk/mediatek/clk-mtk.c @@ -13,6 +13,7 @@ #include <linux/of.h> #include <linux/of_address.h> #include <linux/platform_device.h> +#include <linux/pm_runtime.h> #include <linux/slab.h> #include "clk-mtk.h" @@ -494,6 +495,16 @@ static int __mtk_clk_simple_probe(struct platform_device *pdev, return IS_ERR(base) ? PTR_ERR(base) : -ENOMEM; } + + devm_pm_runtime_enable(&pdev->dev); + /* + * Do a pm_runtime_resume_and_get() to workaround a possible + * deadlock between clk_register() and the genpd framework. + */ + r = pm_runtime_resume_and_get(&pdev->dev); + if (r) + return r; + /* Calculate how many clk_hw_onecell_data entries to allocate */ num_clks = mcd->num_clks + mcd->num_composite_clks; num_clks += mcd->num_fixed_clks + mcd->num_factor_clks; @@ -574,6 +585,8 @@ static int __mtk_clk_simple_probe(struct platform_device *pdev, goto unregister_clks; } + pm_runtime_put(&pdev->dev); + return r; unregister_clks: @@ -604,6 +617,8 @@ static int __mtk_clk_simple_probe(struct platform_device *pdev, free_base: if (mcd->shared_io && base) iounmap(base); + + pm_runtime_put(&pdev->dev); return r; }
mt8183-mfgcfg has a mutual dependency with genpd during the probing stage, which leads to a deadlock in the following call stack: CPU0: genpd_lock --> clk_prepare_lock genpd_power_off_work_fn() genpd_lock() generic_pm_domain::power_off() clk_unprepare() clk_prepare_lock() CPU1: clk_prepare_lock --> genpd_lock clk_register() __clk_core_init() clk_prepare_lock() clk_pm_runtime_get() genpd_lock() Do a runtime PM get at the probe function to make sure clk_register() won't acquire the genpd lock. Instead of only modifying mt8183-mfgcfg, do this on all mediatek clock controller probings because we don't believe this would cause any regression. Verified on MT8183 and MT8192 Chromebooks. Fixes: acddfc2c261b ("clk: mediatek: Add MT8183 clock support") Signed-off-by: Pin-yen Lin <treapking@chromium.org> --- v3: https://lore.kernel.org/all/20240108081834.408403-1-treapking@chromium.org/ Changes in v4: - Remove the need_runtime_pm flag and apply this to all mtk controllers Changes in v3: - Update the commit message and the comments before runtime PM call Changes in v2: - Fix the order of error handling - Update the commit message and add a comment before the runtime PM call drivers/clk/mediatek/clk-mtk.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)