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soc: imx: imx93-blk-ctrl: Add dedicated lockdep class for nested genpd locks

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This is the same approach as being used within imx8mp-blk-ctrl. This fixes
the lockdep warning about 'possible recursive locking detected' with the
following (reduced) backtrace:
genpd_lock_mtx+0x14/0x1c
genpd_runtime_resume+0x108/0x308
__rpm_callback+0x44/0x19c
rpm_callback+0x64/0x70
rpm_resume+0x438/0x6d8
__pm_runtime_resume+0x54/0xb0
imx93_blk_ctrl_power_on+0x100/0x294
_genpd_power_on+0x8c/0x16c
genpd_power_on.part.0+0xa0/0x1a0
__genpd_dev_pm_attach+0x14c/0x2e4
genpd_dev_pm_attach+0x58/0x64
dev_pm_domain_attach+0x1c/0x2c

Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
This commit is contained in:
Alexander Stein 2023-07-06 09:46:29 +02:00 committed by Shawn Guo
parent 06c2afb862
commit 7b95e20e32
1 changed files with 15 additions and 0 deletions
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15
drivers/soc/imx/imx93-blk-ctrl.c
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@ -187,6 +187,8 @@ static int imx93_blk_ctrl_power_off(struct generic_pm_domain *genpd)
return 0;
}
static struct lock_class_key blk_ctrl_genpd_lock_class;
static int imx93_blk_ctrl_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
@ -269,6 +271,19 @@ static int imx93_blk_ctrl_probe(struct platform_device *pdev)
goto cleanup_pds;
}
/*
* We use runtime PM to trigger power on/off of the upstream GPC
* domain, as a strict hierarchical parent/child power domain
* setup doesn't allow us to meet the sequencing requirements.
* This means we have nested locking of genpd locks, without the
* nesting being visible at the genpd level, so we need a
* separate lock class to make lockdep aware of the fact that
* this are separate domain locks that can be nested without a
* self-deadlock.
*/
lockdep_set_class(&domain->genpd.mlock,
&blk_ctrl_genpd_lock_class);
bc->onecell_data.domains[i] = &domain->genpd;
}