Commit 2f7b1d8b authored by Pin-yen Lin's avatar Pin-yen Lin Committed by Stephen Boyd
Browse files

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



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: acddfc2c ("clk: mediatek: Add MT8183 clock support")
Signed-off-by: default avatarPin-yen Lin <treapking@chromium.org>

Link: https://lore.kernel.org/r/20240312115249.3341654-1-treapking@chromium.org


Reviewed-by: default avatarAngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Tested-by: default avatarAngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: default avatarStephen Boyd <sboyd@kernel.org>
parent 754e5287

drivers/clk/mediatek/clk-mtk.c

+15 −0
Original line number Diff line number Diff line
@@ -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;

}