linux-kernel - [PATCH 2/5] clk: imx95-blk-ctl: Fix synchronous abort

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Message-Id: <20250701-imx95-blk-ctl-7-1-v1-2-00db23bd8876@nxp.com>
Date: Tue, 01 Jul 2025 15:04:38 +0800
From: Peng Fan <peng.fan@....com>
To: Michael Turquette <mturquette@...libre.com>, 
 Stephen Boyd <sboyd@...nel.org>, Rob Herring <robh@...nel.org>, 
 Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>, Shawn Guo <shawnguo@...nel.org>, 
 Sascha Hauer <s.hauer@...gutronix.de>, 
 Pengutronix Kernel Team <kernel@...gutronix.de>, 
 Fabio Estevam <festevam@...il.com>, Abel Vesa <abelvesa@...nel.org>, 
 Frank Li <frank.li@....com>
Cc: linux-clk@...r.kernel.org, devicetree@...r.kernel.org, 
 imx@...ts.linux.dev, linux-arm-kernel@...ts.infradead.org, 
 linux-kernel@...r.kernel.org, Abel Vesa <abel.vesa@...aro.org>, 
 Peng Fan <peng.fan@....com>, Laurentiu Palcu <laurentiu.palcu@....nxp.com>
Subject: [PATCH 2/5] clk: imx95-blk-ctl: Fix synchronous abort

From: Laurentiu Palcu <laurentiu.palcu@....nxp.com>

When enabling runtime PM for clock suppliers that also belong to a power
domain, the following crash is thrown:

---
Internal error: synchronous external abort: 0000000096000010 [#1] PREEMPT SMP
Workqueue: events_unbound deferred_probe_work_func
pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : clk_mux_get_parent+0x60/0x90
lr : clk_core_reparent_orphans_nolock+0x58/0xd8
Call trace:
 clk_mux_get_parent+0x60/0x90
 clk_core_reparent_orphans_nolock+0x58/0xd8
 of_clk_add_hw_provider.part.0+0x90/0x100
 of_clk_add_hw_provider+0x1c/0x38
 imx95_bc_probe+0x2e0/0x3f0
 platform_probe+0x70/0xd8

Enabling runtime PM without explicitly resuming the device caused
the power domain cut off after clk_register() is called. As a result,
a crash happens when the clock hardware provider is added and attempts
to access the BLK_CTL register

Fix this by using devm_pm_runtime_enable() instead of pm_runtime_enable()
and getting rid of the pm_runtime_disable() in the cleanup path.

Fixes: 5224b189462f ("clk: imx: add i.MX95 BLK CTL clk driver")
Signed-off-by: Laurentiu Palcu <laurentiu.palcu@....nxp.com>
Signed-off-by: Peng Fan <peng.fan@....com>
---
 drivers/clk/imx/clk-imx95-blk-ctl.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/clk/imx/clk-imx95-blk-ctl.c b/drivers/clk/imx/clk-imx95-blk-ctl.c
index cc2ee2be18195f0e05e911bcb26e284b1a894244..86bdcd21753102b7d160288e7b69bf73da5a5706 100644
--- a/drivers/clk/imx/clk-imx95-blk-ctl.c
+++ b/drivers/clk/imx/clk-imx95-blk-ctl.c
@@ -342,8 +342,10 @@ static int imx95_bc_probe(struct platform_device *pdev)
 	if (!clk_hw_data)
 		return -ENOMEM;
 
-	if (bc_data->rpm_enabled)
-		pm_runtime_enable(&pdev->dev);
+	if (bc_data->rpm_enabled) {
+		devm_pm_runtime_enable(&pdev->dev);
+		pm_runtime_resume_and_get(&pdev->dev);
+	}
 
 	clk_hw_data->num = bc_data->num_clks;
 	hws = clk_hw_data->hws;
@@ -383,8 +385,10 @@ static int imx95_bc_probe(struct platform_device *pdev)
 		goto cleanup;
 	}
 
-	if (pm_runtime_enabled(bc->dev))
+	if (pm_runtime_enabled(bc->dev)) {
+		pm_runtime_put_sync(&pdev->dev);
 		clk_disable_unprepare(bc->clk_apb);
+	}
 
 	return 0;
 
@@ -395,9 +399,6 @@ static int imx95_bc_probe(struct platform_device *pdev)
 		clk_hw_unregister(hws[i]);
 	}
 
-	if (bc_data->rpm_enabled)
-		pm_runtime_disable(&pdev->dev);
-
 	return ret;
 }
 

-- 
2.37.1