6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Pin-yen Lin <treapking@xxxxxxxxxxxx>
[ Upstream commit 2f7b1d8b5505efb0057cd1ab85fca206063ea4c3 ]
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@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20240312115249.3341654-1-treapking@xxxxxxxxxxxx
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
Tested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/clk/mediatek/clk-mtk.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/drivers/clk/mediatek/clk-mtk.c b/drivers/clk/mediatek/clk-mtk.c
index bfabd94a474a5..fa2c1b1c7dee4 100644
--- a/drivers/clk/mediatek/clk-mtk.c
+++ b/drivers/clk/mediatek/clk-mtk.c
@@ -14,6 +14,7 @@
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
#include <linux/slab.h>
#include "clk-mtk.h"
@@ -470,6 +471,16 @@ 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;
@@ -531,6 +542,8 @@ int mtk_clk_simple_probe(struct platform_device *pdev)
goto unregister_clks;
}
+ pm_runtime_put(&pdev->dev);
+
return r;
unregister_clks:
@@ -556,6 +569,8 @@ int mtk_clk_simple_probe(struct platform_device *pdev)
mtk_free_clk_data(clk_data);
if (mcd->shared_io && base)
iounmap(base);
+
+ pm_runtime_put(&pdev->dev);
return r;
}
EXPORT_SYMBOL_GPL(mtk_clk_simple_probe);
--
2.43.0
