clk: samsung: exynos5433: Extract PM support to common ARM64 layer

Exynos5433 clock driver implements PM support internally, which might be
also useful for other Exynos clock drivers. Extract all PM related code
from clk-exynos5433 to common ARM64 functions.

Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Link: https://lore.kernel.org/r/20230307002423.24454-4-semen.protsenko@linaro.org
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Author: Sam Protsenko

drivers/clk/samsung/clk-exynos-arm64.c

@@ -10,6 +10,9 @@
  */
 #include <linux/clk.h>
 #include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/slab.h>
 
 #include "clk-exynos-arm64.h"
 
@@ -21,6 +24,19 @@
 #define GATE_OFF_START		0x2000
 #define GATE_OFF_END		0x2fff
 
+struct exynos_arm64_cmu_data {
+	struct samsung_clk_reg_dump *clk_save;
+	unsigned int nr_clk_save;
+	const struct samsung_clk_reg_dump *clk_suspend;
+	unsigned int nr_clk_suspend;
+
+	struct clk *clk;
+	struct clk **pclks;
+	int nr_pclks;
+
+	struct samsung_clk_provider *ctx;
+};
+
 /**
  * exynos_arm64_init_clocks - Set clocks initial configuration
  * @np:			CMU device tree node with "reg" property (CMU addr)
@@ -76,17 +92,63 @@ static int __init exynos_arm64_enable_bus_clk(struct device *dev,
 	if (!cmu->clk_name)
 		return 0;
 
-	if (dev)
+	if (dev) {
+		struct exynos_arm64_cmu_data *data;
+
 		parent_clk = clk_get(dev, cmu->clk_name);
-	else
+		data = dev_get_drvdata(dev);
+		if (data)
+			data->clk = parent_clk;
+	} else {
 		parent_clk = of_clk_get_by_name(np, cmu->clk_name);
+	}
 
 	if (IS_ERR(parent_clk))
 		return PTR_ERR(parent_clk);
 
 	return clk_prepare_enable(parent_clk);
 }
 
+static int __init exynos_arm64_cmu_prepare_pm(struct device *dev,
+		const struct samsung_cmu_info *cmu)
+{
+	struct exynos_arm64_cmu_data *data = dev_get_drvdata(dev);
+	int i;
+
+	data->clk_save = samsung_clk_alloc_reg_dump(cmu->clk_regs,
+						    cmu->nr_clk_regs);
+	if (!data->clk_save)
+		return -ENOMEM;
+
+	data->nr_clk_save = cmu->nr_clk_regs;
+	data->clk_suspend = cmu->suspend_regs;
+	data->nr_clk_suspend = cmu->nr_suspend_regs;
+	data->nr_pclks = of_clk_get_parent_count(dev->of_node);
+	if (!data->nr_pclks)
+		return 0;
+
+	data->pclks = devm_kcalloc(dev, sizeof(struct clk *), data->nr_pclks,
+				   GFP_KERNEL);
+	if (!data->pclks) {
+		kfree(data->clk_save);
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < data->nr_pclks; i++) {
+		struct clk *clk = of_clk_get(dev->of_node, i);
+
+		if (IS_ERR(clk)) {
+			kfree(data->clk_save);
+			while (--i >= 0)
+				clk_put(data->pclks[i]);
+			return PTR_ERR(clk);
+		}
+		data->pclks[i] = clk;
+	}
+
+	return 0;
+}
+
 /**
  * exynos_arm64_register_cmu - Register specified Exynos CMU domain
  * @dev:	Device object; may be NULL if this function is not being
@@ -117,3 +179,113 @@ void __init exynos_arm64_register_cmu(struct device *dev,
 	exynos_arm64_init_clocks(np, cmu->clk_regs, cmu->nr_clk_regs);
 	samsung_cmu_register_one(np, cmu);
 }
+
+/**
+ * exynos_arm64_register_cmu_pm - Register Exynos CMU domain with PM support
+ *
+ * @pdev:	Platform device object
+ * @set_manual:	If true, set gate clocks to manual mode
+ *
+ * It's a version of exynos_arm64_register_cmu() with PM support. Should be
+ * called from probe function of platform driver.
+ *
+ * Return: 0 on success, or negative error code on error.
+ */
+int __init exynos_arm64_register_cmu_pm(struct platform_device *pdev,
+					bool set_manual)
+{
+	const struct samsung_cmu_info *cmu;
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct exynos_arm64_cmu_data *data;
+	void __iomem *reg_base;
+	int ret;
+
+	cmu = of_device_get_match_data(dev);
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, data);
+
+	ret = exynos_arm64_cmu_prepare_pm(dev, cmu);
+	if (ret)
+		return ret;
+
+	/*
+	 * Try to boot even if the parent clock enablement fails, as it might be
+	 * already enabled by bootloader.
+	 */
+	ret = exynos_arm64_enable_bus_clk(dev, NULL, cmu);
+	if (ret)
+		dev_err(dev, "%s: could not enable bus clock %s; err = %d\n",
+		       __func__, cmu->clk_name, ret);
+
+	if (set_manual)
+		exynos_arm64_init_clocks(np, cmu->clk_regs, cmu->nr_clk_regs);
+
+	reg_base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(reg_base))
+		return PTR_ERR(reg_base);
+
+	data->ctx = samsung_clk_init(dev, reg_base, cmu->nr_clk_ids);
+
+	/*
+	 * Enable runtime PM here to allow the clock core using runtime PM
+	 * for the registered clocks. Additionally, we increase the runtime
+	 * PM usage count before registering the clocks, to prevent the
+	 * clock core from runtime suspending the device.
+	 */
+	pm_runtime_get_noresume(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+
+	samsung_cmu_register_clocks(data->ctx, cmu);
+	samsung_clk_of_add_provider(dev->of_node, data->ctx);
+	pm_runtime_put_sync(dev);
+
+	return 0;
+}
+
+int exynos_arm64_cmu_suspend(struct device *dev)
+{
+	struct exynos_arm64_cmu_data *data = dev_get_drvdata(dev);
+	int i;
+
+	samsung_clk_save(data->ctx->reg_base, data->clk_save,
+			 data->nr_clk_save);
+
+	for (i = 0; i < data->nr_pclks; i++)
+		clk_prepare_enable(data->pclks[i]);
+
+	/* For suspend some registers have to be set to certain values */
+	samsung_clk_restore(data->ctx->reg_base, data->clk_suspend,
+			    data->nr_clk_suspend);
+
+	for (i = 0; i < data->nr_pclks; i++)
+		clk_disable_unprepare(data->pclks[i]);
+
+	clk_disable_unprepare(data->clk);
+
+	return 0;
+}
+
+int exynos_arm64_cmu_resume(struct device *dev)
+{
+	struct exynos_arm64_cmu_data *data = dev_get_drvdata(dev);
+	int i;
+
+	clk_prepare_enable(data->clk);
+
+	for (i = 0; i < data->nr_pclks; i++)
+		clk_prepare_enable(data->pclks[i]);
+
+	samsung_clk_restore(data->ctx->reg_base, data->clk_save,
+			    data->nr_clk_save);
+
+	for (i = 0; i < data->nr_pclks; i++)
+		clk_disable_unprepare(data->pclks[i]);
+
+	return 0;
+}

drivers/clk/samsung/clk-exynos-arm64.h

@@ -16,5 +16,8 @@
 
 void exynos_arm64_register_cmu(struct device *dev,
 		struct device_node *np, const struct samsung_cmu_info *cmu);
+int exynos_arm64_register_cmu_pm(struct platform_device *pdev, bool set_manual);
+int exynos_arm64_cmu_suspend(struct device *dev);
+int exynos_arm64_cmu_resume(struct device *dev);
 
 #endif /* __CLK_EXYNOS_ARM64_H */