linux-kernel - [PATCH 4/5] crypto: stm32/crc: don't sleep in runtime pm

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Date:   Tue, 12 May 2020 16:11:12 +0200
From:   Nicolas Toromanoff <nicolas.toromanoff@...com>
To:     Herbert Xu <herbert@...dor.apana.org.au>,
        "David S . Miller" <davem@...emloft.net>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...com>
CC:     Nicolas Toromanoff <nicolas.toromanoff@...com>,
        <linux-crypto@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH 4/5] crypto: stm32/crc: don't sleep in runtime pm

Ensure stm32_crc_update() and stm32_crc_init() can be called
in atomic context and can't sleep.

Add pm_runtime_irq_safe() to make pm_runtime_get_sync() atomic.
Change runtime pm to call clk_enable()/clk_disable() and change
system pm to unprepare/prepare the clock and force runtime pm
suspend/resume.

Signed-off-by: Nicolas Toromanoff <nicolas.toromanoff@...com>
---
 drivers/crypto/stm32/stm32-crc32.c | 45 ++++++++++++++++++++++++------
 1 file changed, 36 insertions(+), 9 deletions(-)

diff --git a/drivers/crypto/stm32/stm32-crc32.c b/drivers/crypto/stm32/stm32-crc32.c
index 10304511f9b4..413415c216ef 100644
--- a/drivers/crypto/stm32/stm32-crc32.c
+++ b/drivers/crypto/stm32/stm32-crc32.c
@@ -297,6 +297,7 @@ static int stm32_crc_probe(struct platform_device *pdev)
 
 	pm_runtime_get_noresume(dev);
 	pm_runtime_set_active(dev);
+	pm_runtime_irq_safe(dev);
 	pm_runtime_enable(dev);
 
 	platform_set_drvdata(pdev, crc);
@@ -350,34 +351,60 @@ static int stm32_crc_remove(struct platform_device *pdev)
 	return 0;
 }
 
-#ifdef CONFIG_PM
-static int stm32_crc_runtime_suspend(struct device *dev)
+static int __maybe_unused stm32_crc_suspend(struct device *dev)
 {
 	struct stm32_crc *crc = dev_get_drvdata(dev);
+	int ret;
 
-	clk_disable_unprepare(crc->clk);
+	ret = pm_runtime_force_suspend(dev);
+	if (ret)
+		return ret;
+
+	clk_unprepare(crc->clk);
 
 	return 0;
 }
 
-static int stm32_crc_runtime_resume(struct device *dev)
+static int __maybe_unused stm32_crc_resume(struct device *dev)
 {
 	struct stm32_crc *crc = dev_get_drvdata(dev);
 	int ret;
 
-	ret = clk_prepare_enable(crc->clk);
+	ret = clk_prepare(crc->clk);
 	if (ret) {
-		dev_err(crc->dev, "Failed to prepare_enable clock\n");
+		dev_err(crc->dev, "Failed to prepare clock\n");
+		return ret;
+	}
+
+	return pm_runtime_force_resume(dev);
+}
+
+static int __maybe_unused stm32_crc_runtime_suspend(struct device *dev)
+{
+	struct stm32_crc *crc = dev_get_drvdata(dev);
+
+	clk_disable(crc->clk);
+
+	return 0;
+}
+
+static int __maybe_unused stm32_crc_runtime_resume(struct device *dev)
+{
+	struct stm32_crc *crc = dev_get_drvdata(dev);
+	int ret;
+
+	ret = clk_enable(crc->clk);
+	if (ret) {
+		dev_err(crc->dev, "Failed to enable clock\n");
 		return ret;
 	}
 
 	return 0;
 }
-#endif
 
 static const struct dev_pm_ops stm32_crc_pm_ops = {
-	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
-				pm_runtime_force_resume)
+	SET_SYSTEM_SLEEP_PM_OPS(stm32_crc_suspend,
+				stm32_crc_resume)
 	SET_RUNTIME_PM_OPS(stm32_crc_runtime_suspend,
 			   stm32_crc_runtime_resume, NULL)
 };
-- 
2.17.1