diff mbox series

[v2,09/10] hwrng: stm32 - rework power management sequences

Message ID 20230911120203.774632-10-gatien.chevallier@foss.st.com
State Superseded
Headers show
Series hwrng: stm32: support STM32MP13x platforms | expand

Commit Message

Gatien CHEVALLIER Sept. 11, 2023, 12:02 p.m. UTC
Implement stm32_rng_suspend()/stm32_rng_resume() low-power APIs
called when the hardware block context will be lost.

There is no need to save the RNG_CR register in
stm32_rng_runtime_suspend() as the context is not lost. Therefore,
only enable/disable the RNG in the runtime sequences.

Signed-off-by: Gatien Chevallier <gatien.chevallier@foss.st.com>
---

Changes in V2:
	- Use pm_ptr() and add __maybe_unused to the pm API

 drivers/char/hw_random/stm32-rng.c | 108 ++++++++++++++++++++++++++---
 1 file changed, 97 insertions(+), 11 deletions(-)

Comments

kernel test robot Sept. 12, 2023, 12:45 p.m. UTC | #1
Hi Gatien,

kernel test robot noticed the following build warnings:

[auto build test WARNING on atorgue-stm32/stm32-next]
[also build test WARNING on robh/for-next herbert-crypto-2.6/master herbert-cryptodev-2.6/master linus/master v6.6-rc1 next-20230912]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Gatien-Chevallier/dt-bindings-rng-introduce-new-compatible-for-STM32MP13x/20230912-051851
base:   https://git.kernel.org/pub/scm/linux/kernel/git/atorgue/stm32.git stm32-next
patch link:    https://lore.kernel.org/r/20230911120203.774632-10-gatien.chevallier%40foss.st.com
patch subject: [PATCH v2 09/10] hwrng: stm32 - rework power management sequences
config: arm64-randconfig-r003-20230912 (https://download.01.org/0day-ci/archive/20230912/202309122017.GsJspucF-lkp@intel.com/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20230912/202309122017.GsJspucF-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202309122017.GsJspucF-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/char/hw_random/stm32-rng.c:472:21: warning: attribute declaration must precede definition [-Wignored-attributes]
     472 | static const struct __maybe_unused dev_pm_ops stm32_rng_pm_ops = {
         |                     ^
   include/linux/compiler_attributes.h:344:56: note: expanded from macro '__maybe_unused'
     344 | #define __maybe_unused                  __attribute__((__unused__))
         |                                                        ^
   include/linux/pm.h:286:8: note: previous definition is here
     286 | struct dev_pm_ops {
         |        ^
   1 warning generated.


vim +472 drivers/char/hw_random/stm32-rng.c

   471	
 > 472	static const struct __maybe_unused dev_pm_ops stm32_rng_pm_ops = {
   473		SET_RUNTIME_PM_OPS(stm32_rng_runtime_suspend,
   474				   stm32_rng_runtime_resume, NULL)
   475		SET_SYSTEM_SLEEP_PM_OPS(stm32_rng_suspend,
   476					stm32_rng_resume)
   477	};
   478
diff mbox series

Patch

diff --git a/drivers/char/hw_random/stm32-rng.c b/drivers/char/hw_random/stm32-rng.c
index 4a602d666dad..01198a2e32c6 100644
--- a/drivers/char/hw_random/stm32-rng.c
+++ b/drivers/char/hw_random/stm32-rng.c
@@ -55,11 +55,25 @@  struct stm32_rng_data {
 	bool	has_cond_reset;
 };
 
+/**
+ * struct stm32_rng_config - RNG configuration data
+ *
+ * @cr:			RNG configuration. 0 means default hardware RNG configuration
+ * @nscr:		Noise sources control configuration.
+ * @htcr:		Health tests configuration.
+ */
+struct stm32_rng_config {
+	u32 cr;
+	u32 nscr;
+	u32 htcr;
+};
+
 struct stm32_rng_private {
 	struct hwrng rng;
 	void __iomem *base;
 	struct clk *clk;
 	struct reset_control *rst;
+	struct stm32_rng_config pm_conf;
 	const struct stm32_rng_data *data;
 	bool ced;
 	bool lock_conf;
@@ -355,11 +369,10 @@  static int stm32_rng_remove(struct platform_device *ofdev)
 	return 0;
 }
 
-#ifdef CONFIG_PM
-static int stm32_rng_runtime_suspend(struct device *dev)
+static int __maybe_unused stm32_rng_runtime_suspend(struct device *dev)
 {
-	u32 reg;
 	struct stm32_rng_private *priv = dev_get_drvdata(dev);
+	u32 reg;
 
 	reg = readl_relaxed(priv->base + RNG_CR);
 	reg &= ~RNG_CR_RNGEN;
@@ -369,25 +382,98 @@  static int stm32_rng_runtime_suspend(struct device *dev)
 	return 0;
 }
 
-static int stm32_rng_runtime_resume(struct device *dev)
+static int __maybe_unused stm32_rng_suspend(struct device *dev)
+{
+	struct stm32_rng_private *priv = dev_get_drvdata(dev);
+
+	if (priv->data->has_cond_reset) {
+		priv->pm_conf.nscr = readl_relaxed(priv->base + RNG_NSCR);
+		priv->pm_conf.htcr = readl_relaxed(priv->base + RNG_HTCR);
+	}
+
+	/* Do not save that RNG is enabled as it will be handled at resume */
+	priv->pm_conf.cr = readl_relaxed(priv->base + RNG_CR) & ~RNG_CR_RNGEN;
+
+	writel_relaxed(priv->pm_conf.cr, priv->base + RNG_CR);
+
+	clk_disable_unprepare(priv->clk);
+
+	return 0;
+}
+
+static int __maybe_unused stm32_rng_runtime_resume(struct device *dev)
 {
-	u32 reg;
 	struct stm32_rng_private *priv = dev_get_drvdata(dev);
+	int err;
+	u32 reg;
+
+	err = clk_prepare_enable(priv->clk);
+	if (err)
+		return err;
+
+	/* Clean error indications */
+	writel_relaxed(0, priv->base + RNG_SR);
 
-	clk_prepare_enable(priv->clk);
 	reg = readl_relaxed(priv->base + RNG_CR);
 	reg |= RNG_CR_RNGEN;
 	writel_relaxed(reg, priv->base + RNG_CR);
 
 	return 0;
 }
-#endif
 
-static const struct dev_pm_ops stm32_rng_pm_ops = {
+static int __maybe_unused stm32_rng_resume(struct device *dev)
+{
+	struct stm32_rng_private *priv = dev_get_drvdata(dev);
+	int err;
+	u32 reg;
+
+	err = clk_prepare_enable(priv->clk);
+	if (err)
+		return err;
+
+	/* Clean error indications */
+	writel_relaxed(0, priv->base + RNG_SR);
+
+	if (priv->data->has_cond_reset) {
+		/*
+		 * Correct configuration in bits [29:4] must be set in the same
+		 * access that set RNG_CR_CONDRST bit. Else config setting is
+		 * not taken into account. CONFIGLOCK bit must also be unset but
+		 * it is not handled at the moment.
+		 */
+		writel_relaxed(priv->pm_conf.cr | RNG_CR_CONDRST, priv->base + RNG_CR);
+
+		writel_relaxed(priv->pm_conf.nscr, priv->base + RNG_NSCR);
+		writel_relaxed(priv->pm_conf.htcr, priv->base + RNG_HTCR);
+
+		reg = readl_relaxed(priv->base + RNG_CR);
+		reg |= RNG_CR_RNGEN;
+		reg &= ~RNG_CR_CONDRST;
+		writel_relaxed(reg, priv->base + RNG_CR);
+
+		err = readl_relaxed_poll_timeout_atomic(priv->base + RNG_CR, reg,
+							reg & ~RNG_CR_CONDRST, 10, 100000);
+
+		if (err) {
+			clk_disable_unprepare(priv->clk);
+			dev_err((struct device *)priv->rng.priv,
+				"%s: timeout:%x CR: %x!\n", __func__, err, reg);
+			return -EINVAL;
+		}
+	} else {
+		reg = priv->pm_conf.cr;
+		reg |= RNG_CR_RNGEN;
+		writel_relaxed(reg, priv->base + RNG_CR);
+	}
+
+	return 0;
+}
+
+static const struct __maybe_unused dev_pm_ops stm32_rng_pm_ops = {
 	SET_RUNTIME_PM_OPS(stm32_rng_runtime_suspend,
 			   stm32_rng_runtime_resume, NULL)
-	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
-				pm_runtime_force_resume)
+	SET_SYSTEM_SLEEP_PM_OPS(stm32_rng_suspend,
+				stm32_rng_resume)
 };
 
 static const struct stm32_rng_data stm32mp13_rng_data = {
@@ -467,7 +553,7 @@  static int stm32_rng_probe(struct platform_device *ofdev)
 static struct platform_driver stm32_rng_driver = {
 	.driver = {
 		.name = "stm32-rng",
-		.pm = &stm32_rng_pm_ops,
+		.pm = pm_ptr(&stm32_rng_pm_ops),
 		.of_match_table = stm32_rng_match,
 	},
 	.probe = stm32_rng_probe,