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clk: mediatek: Do a runtime PM get on controllers during probe

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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: acddfc2c26 ("clk: mediatek: Add MT8183 clock support")
Signed-off-by: Pin-yen Lin <treapking@chromium.org>

Link: https://lore.kernel.org/r/20240312115249.3341654-1-treapking@chromium.org
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Tested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
This commit is contained in:
Pin-yen Lin 2024-03-12 19:51:55 +08:00 committed by Stephen Boyd
parent 754e5287c7
commit 2f7b1d8b55
1 changed files with 15 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

15
drivers/clk/mediatek/clk-mtk.c
View file

@ -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;
}