soc: rockchip: power-domain: Add power domain driver

This driver is found on RK3288 SoCs.

In order to meet high performance and low power requirements, a power
management unit is designed or saving power when RK3288 in low power
mode.
The RK3288 PMU is dedicated for managing the power of the whole chip.

PMU can work in the Low Power Mode by setting bit[0] of PMU_PWRMODE_CON
register. After setting the register, PMU would enter the Low Power mode.
In the low power mode, pmu will auto power on/off the specified power
domain, send idle req to specified power domain, shut down/up pll and
so on. All of above are configurable by setting corresponding registers.

Signed-off-by: Caesar Wang <wxt@rock-chips.com>
Reviewed-by: Kevin Hilman <khilman@linaro.org>

[replace dsb() with dsb(sy) for arm64 buildability; sy is the default,
so no functional change; adapt to per-user clocks in genpd]
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

drivers/soc/Kconfig

@@ -2,6 +2,7 @@ menu "SOC (System On Chip) specific Drivers"
 
 source "drivers/soc/mediatek/Kconfig"
 source "drivers/soc/qcom/Kconfig"
+source "drivers/soc/rockchip/Kconfig"
 source "drivers/soc/sunxi/Kconfig"
 source "drivers/soc/ti/Kconfig"
 source "drivers/soc/versatile/Kconfig"

drivers/soc/Makefile

@@ -5,6 +5,7 @@
 obj-$(CONFIG_MACH_DOVE)		+= dove/
 obj-$(CONFIG_ARCH_MEDIATEK)	+= mediatek/
 obj-$(CONFIG_ARCH_QCOM)		+= qcom/
+obj-$(CONFIG_ARCH_ROCKCHIP)		+= rockchip/
 obj-$(CONFIG_ARCH_SUNXI)	+= sunxi/
 obj-$(CONFIG_ARCH_TEGRA)	+= tegra/
 obj-$(CONFIG_SOC_TI)		+= ti/

drivers/soc/rockchip/Kconfig

@@ -0,0 +1,14 @@
+#
+# Rockchip Soc drivers
+#
+config ROCKCHIP_PM_DOMAINS
+        bool "Rockchip generic power domain"
+        depends on PM
+        select PM_GENERIC_DOMAINS
+        help
+          Say y here to enable power domain support.
+          In order to meet high performance and low power requirements, a power
+          management unit is designed or saving power when RK3288 in low power
+          mode. The RK3288 PMU is dedicated for managing the power of the whole chip.
+
+          If unsure, say N.

drivers/soc/rockchip/Makefile

@@ -0,0 +1,4 @@
+#
+# Rockchip Soc drivers
+#
+obj-$(CONFIG_ROCKCHIP_PM_DOMAINS) += pm_domains.o

drivers/soc/rockchip/pm_domains.c

@@ -0,0 +1,490 @@
+/*
+ * Rockchip Generic power domain support.
+ *
+ * Copyright (c) 2015 ROCKCHIP, Co. Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/io.h>
+#include <linux/err.h>
+#include <linux/pm_clock.h>
+#include <linux/pm_domain.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/clk.h>
+#include <linux/regmap.h>
+#include <linux/mfd/syscon.h>
+#include <dt-bindings/power/rk3288-power.h>
+
+struct rockchip_domain_info {
+	int pwr_mask;
+	int status_mask;
+	int req_mask;
+	int idle_mask;
+	int ack_mask;
+};
+
+struct rockchip_pmu_info {
+	u32 pwr_offset;
+	u32 status_offset;
+	u32 req_offset;
+	u32 idle_offset;
+	u32 ack_offset;
+
+	u32 core_pwrcnt_offset;
+	u32 gpu_pwrcnt_offset;
+
+	unsigned int core_power_transition_time;
+	unsigned int gpu_power_transition_time;
+
+	int num_domains;
+	const struct rockchip_domain_info *domain_info;
+};
+
+struct rockchip_pm_domain {
+	struct generic_pm_domain genpd;
+	const struct rockchip_domain_info *info;
+	struct rockchip_pmu *pmu;
+	int num_clks;
+	struct clk *clks[];
+};
+
+struct rockchip_pmu {
+	struct device *dev;
+	struct regmap *regmap;
+	const struct rockchip_pmu_info *info;
+	struct mutex mutex; /* mutex lock for pmu */
+	struct genpd_onecell_data genpd_data;
+	struct generic_pm_domain *domains[];
+};
+
+#define to_rockchip_pd(gpd) container_of(gpd, struct rockchip_pm_domain, genpd)
+
+#define DOMAIN(pwr, status, req, idle, ack)	\
+{						\
+	.pwr_mask = BIT(pwr),			\
+	.status_mask = BIT(status),		\
+	.req_mask = BIT(req),			\
+	.idle_mask = BIT(idle),			\
+	.ack_mask = BIT(ack),			\
+}
+
+#define DOMAIN_RK3288(pwr, status, req)		\
+	DOMAIN(pwr, status, req, req, (req) + 16)
+
+static bool rockchip_pmu_domain_is_idle(struct rockchip_pm_domain *pd)
+{
+	struct rockchip_pmu *pmu = pd->pmu;
+	const struct rockchip_domain_info *pd_info = pd->info;
+	unsigned int val;
+
+	regmap_read(pmu->regmap, pmu->info->idle_offset, &val);
+	return (val & pd_info->idle_mask) == pd_info->idle_mask;
+}
+
+static int rockchip_pmu_set_idle_request(struct rockchip_pm_domain *pd,
+					 bool idle)
+{
+	const struct rockchip_domain_info *pd_info = pd->info;
+	struct rockchip_pmu *pmu = pd->pmu;
+	unsigned int val;
+
+	regmap_update_bits(pmu->regmap, pmu->info->req_offset,
+			   pd_info->req_mask, idle ? -1U : 0);
+
+	dsb(sy);
+
+	do {
+		regmap_read(pmu->regmap, pmu->info->ack_offset, &val);
+	} while ((val & pd_info->ack_mask) != (idle ? pd_info->ack_mask : 0));
+
+	while (rockchip_pmu_domain_is_idle(pd) != idle)
+		cpu_relax();
+
+	return 0;
+}
+
+static bool rockchip_pmu_domain_is_on(struct rockchip_pm_domain *pd)
+{
+	struct rockchip_pmu *pmu = pd->pmu;
+	unsigned int val;
+
+	regmap_read(pmu->regmap, pmu->info->status_offset, &val);
+
+	/* 1'b0: power on, 1'b1: power off */
+	return !(val & pd->info->status_mask);
+}
+
+static void rockchip_do_pmu_set_power_domain(struct rockchip_pm_domain *pd,
+					     bool on)
+{
+	struct rockchip_pmu *pmu = pd->pmu;
+
+	regmap_update_bits(pmu->regmap, pmu->info->pwr_offset,
+			   pd->info->pwr_mask, on ? 0 : -1U);
+
+	dsb(sy);
+
+	while (rockchip_pmu_domain_is_on(pd) != on)
+		cpu_relax();
+}
+
+static int rockchip_pd_power(struct rockchip_pm_domain *pd, bool power_on)
+{
+	int i;
+
+	mutex_lock(&pd->pmu->mutex);
+
+	if (rockchip_pmu_domain_is_on(pd) != power_on) {
+		for (i = 0; i < pd->num_clks; i++)
+			clk_enable(pd->clks[i]);
+
+		if (!power_on) {
+			/* FIXME: add code to save AXI_QOS */
+
+			/* if powering down, idle request to NIU first */
+			rockchip_pmu_set_idle_request(pd, true);
+		}
+
+		rockchip_do_pmu_set_power_domain(pd, power_on);
+
+		if (power_on) {
+			/* if powering up, leave idle mode */
+			rockchip_pmu_set_idle_request(pd, false);
+
+			/* FIXME: add code to restore AXI_QOS */
+		}
+
+		for (i = pd->num_clks - 1; i >= 0; i--)
+			clk_disable(pd->clks[i]);
+	}
+
+	mutex_unlock(&pd->pmu->mutex);
+	return 0;
+}
+
+static int rockchip_pd_power_on(struct generic_pm_domain *domain)
+{
+	struct rockchip_pm_domain *pd = to_rockchip_pd(domain);
+
+	return rockchip_pd_power(pd, true);
+}
+
+static int rockchip_pd_power_off(struct generic_pm_domain *domain)
+{
+	struct rockchip_pm_domain *pd = to_rockchip_pd(domain);
+
+	return rockchip_pd_power(pd, false);
+}
+
+static int rockchip_pd_attach_dev(struct generic_pm_domain *genpd,
+				  struct device *dev)
+{
+	struct clk *clk;
+	int i;
+	int error;
+
+	dev_dbg(dev, "attaching to power domain '%s'\n", genpd->name);
+
+	error = pm_clk_create(dev);
+	if (error) {
+		dev_err(dev, "pm_clk_create failed %d\n", error);
+		return error;
+	}
+
+	i = 0;
+	while ((clk = of_clk_get(dev->of_node, i++)) && !IS_ERR(clk)) {
+		dev_dbg(dev, "adding clock '%pC' to list of PM clocks\n", clk);
+		error = pm_clk_add_clk(dev, clk);
+		if (error) {
+			dev_err(dev, "pm_clk_add_clk failed %d\n", error);
+			clk_put(clk);
+			pm_clk_destroy(dev);
+			return error;
+		}
+	}
+
+	return 0;
+}
+
+static void rockchip_pd_detach_dev(struct generic_pm_domain *genpd,
+				   struct device *dev)
+{
+	dev_dbg(dev, "detaching from power domain '%s'\n", genpd->name);
+
+	pm_clk_destroy(dev);
+}
+
+static int rockchip_pm_add_one_domain(struct rockchip_pmu *pmu,
+				      struct device_node *node)
+{
+	const struct rockchip_domain_info *pd_info;
+	struct rockchip_pm_domain *pd;
+	struct clk *clk;
+	int clk_cnt;
+	int i;
+	u32 id;
+	int error;
+
+	error = of_property_read_u32(node, "reg", &id);
+	if (error) {
+		dev_err(pmu->dev,
+			"%s: failed to retrieve domain id (reg): %d\n",
+			node->name, error);
+		return -EINVAL;
+	}
+
+	if (id >= pmu->info->num_domains) {
+		dev_err(pmu->dev, "%s: invalid domain id %d\n",
+			node->name, id);
+		return -EINVAL;
+	}
+
+	pd_info = &pmu->info->domain_info[id];
+	if (!pd_info) {
+		dev_err(pmu->dev, "%s: undefined domain id %d\n",
+			node->name, id);
+		return -EINVAL;
+	}
+
+	clk_cnt = of_count_phandle_with_args(node, "clocks", "#clock-cells");
+	pd = devm_kzalloc(pmu->dev,
+			  sizeof(*pd) + clk_cnt * sizeof(pd->clks[0]),
+			  GFP_KERNEL);
+	if (!pd)
+		return -ENOMEM;
+
+	pd->info = pd_info;
+	pd->pmu = pmu;
+
+	for (i = 0; i < clk_cnt; i++) {
+		clk = of_clk_get(node, i);
+		if (IS_ERR(clk)) {
+			error = PTR_ERR(clk);
+			dev_err(pmu->dev,
+				"%s: failed to get clk %pC (index %d): %d\n",
+				node->name, clk, i, error);
+			goto err_out;
+		}
+
+		error = clk_prepare(clk);
+		if (error) {
+			dev_err(pmu->dev,
+				"%s: failed to prepare clk %pC (index %d): %d\n",
+				node->name, clk, i, error);
+			clk_put(clk);
+			goto err_out;
+		}
+
+		pd->clks[pd->num_clks++] = clk;
+
+		dev_dbg(pmu->dev, "added clock '%pC' to domain '%s'\n",
+			clk, node->name);
+	}
+
+	error = rockchip_pd_power(pd, true);
+	if (error) {
+		dev_err(pmu->dev,
+			"failed to power on domain '%s': %d\n",
+			node->name, error);
+		goto err_out;
+	}
+
+	pd->genpd.name = node->name;
+	pd->genpd.power_off = rockchip_pd_power_off;
+	pd->genpd.power_on = rockchip_pd_power_on;
+	pd->genpd.attach_dev = rockchip_pd_attach_dev;
+	pd->genpd.detach_dev = rockchip_pd_detach_dev;
+	pd->genpd.flags = GENPD_FLAG_PM_CLK;
+	pm_genpd_init(&pd->genpd, NULL, false);
+
+	pmu->genpd_data.domains[id] = &pd->genpd;
+	return 0;
+
+err_out:
+	while (--i >= 0) {
+		clk_unprepare(pd->clks[i]);
+		clk_put(pd->clks[i]);
+	}
+	return error;
+}
+
+static void rockchip_pm_remove_one_domain(struct rockchip_pm_domain *pd)
+{
+	int i;
+
+	for (i = 0; i < pd->num_clks; i++) {
+		clk_unprepare(pd->clks[i]);
+		clk_put(pd->clks[i]);
+	}
+
+	/* protect the zeroing of pm->num_clks */
+	mutex_lock(&pd->pmu->mutex);
+	pd->num_clks = 0;
+	mutex_unlock(&pd->pmu->mutex);
+
+	/* devm will free our memory */
+}
+
+static void rockchip_pm_domain_cleanup(struct rockchip_pmu *pmu)
+{
+	struct generic_pm_domain *genpd;
+	struct rockchip_pm_domain *pd;
+	int i;
+
+	for (i = 0; i < pmu->genpd_data.num_domains; i++) {
+		genpd = pmu->genpd_data.domains[i];
+		if (genpd) {
+			pd = to_rockchip_pd(genpd);
+			rockchip_pm_remove_one_domain(pd);
+		}
+	}
+
+	/* devm will free our memory */
+}
+
+static void rockchip_configure_pd_cnt(struct rockchip_pmu *pmu,
+				      u32 domain_reg_offset,
+				      unsigned int count)
+{
+	/* First configure domain power down transition count ... */
+	regmap_write(pmu->regmap, domain_reg_offset, count);
+	/* ... and then power up count. */
+	regmap_write(pmu->regmap, domain_reg_offset + 4, count);
+}
+
+static int rockchip_pm_domain_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct device_node *node;
+	struct device *parent;
+	struct rockchip_pmu *pmu;
+	const struct of_device_id *match;
+	const struct rockchip_pmu_info *pmu_info;
+	int error;
+
+	if (!np) {
+		dev_err(dev, "device tree node not found\n");
+		return -ENODEV;
+	}
+
+	match = of_match_device(dev->driver->of_match_table, dev);
+	if (!match || !match->data) {
+		dev_err(dev, "missing pmu data\n");
+		return -EINVAL;
+	}
+
+	pmu_info = match->data;
+
+	pmu = devm_kzalloc(dev,
+			   sizeof(*pmu) +
+				pmu_info->num_domains * sizeof(pmu->domains[0]),
+			   GFP_KERNEL);
+	if (!pmu)
+		return -ENOMEM;
+
+	pmu->dev = &pdev->dev;
+	mutex_init(&pmu->mutex);
+
+	pmu->info = pmu_info;
+
+	pmu->genpd_data.domains = pmu->domains;
+	pmu->genpd_data.num_domains = pmu_info->num_domains;
+
+	parent = dev->parent;
+	if (!parent) {
+		dev_err(dev, "no parent for syscon devices\n");
+		return -ENODEV;
+	}
+
+	pmu->regmap = syscon_node_to_regmap(parent->of_node);
+
+	/*
+	 * Configure power up and down transition delays for CORE
+	 * and GPU domains.
+	 */
+	rockchip_configure_pd_cnt(pmu, pmu_info->core_pwrcnt_offset,
+				  pmu_info->core_power_transition_time);
+	rockchip_configure_pd_cnt(pmu, pmu_info->gpu_pwrcnt_offset,
+				  pmu_info->gpu_power_transition_time);
+
+	error = -ENODEV;
+
+	for_each_available_child_of_node(np, node) {
+		error = rockchip_pm_add_one_domain(pmu, node);
+		if (error) {
+			dev_err(dev, "failed to handle node %s: %d\n",
+				node->name, error);
+			goto err_out;
+		}
+	}
+
+	if (error) {
+		dev_dbg(dev, "no power domains defined\n");
+		goto err_out;
+	}
+
+	of_genpd_add_provider_onecell(np, &pmu->genpd_data);
+
+	return 0;
+
+err_out:
+	rockchip_pm_domain_cleanup(pmu);
+	return error;
+}
+
+static const struct rockchip_domain_info rk3288_pm_domains[] = {
+	[RK3288_PD_VIO]		= DOMAIN_RK3288(7, 7, 4),
+	[RK3288_PD_HEVC]	= DOMAIN_RK3288(14, 10, 9),
+	[RK3288_PD_VIDEO]	= DOMAIN_RK3288(8, 8, 3),
+	[RK3288_PD_GPU]		= DOMAIN_RK3288(9, 9, 2),
+};
+
+static const struct rockchip_pmu_info rk3288_pmu = {
+	.pwr_offset = 0x08,
+	.status_offset = 0x0c,
+	.req_offset = 0x10,
+	.idle_offset = 0x14,
+	.ack_offset = 0x14,
+
+	.core_pwrcnt_offset = 0x34,
+	.gpu_pwrcnt_offset = 0x3c,
+
+	.core_power_transition_time = 24, /* 1us */
+	.gpu_power_transition_time = 24, /* 1us */
+
+	.num_domains = ARRAY_SIZE(rk3288_pm_domains),
+	.domain_info = rk3288_pm_domains,
+};
+
+static const struct of_device_id rockchip_pm_domain_dt_match[] = {
+	{
+		.compatible = "rockchip,rk3288-power-controller",
+		.data = (void *)&rk3288_pmu,
+	},
+	{ /* sentinel */ },
+};
+
+static struct platform_driver rockchip_pm_domain_driver = {
+	.probe = rockchip_pm_domain_probe,
+	.driver = {
+		.name   = "rockchip-pm-domain",
+		.of_match_table = rockchip_pm_domain_dt_match,
+		/*
+		 * We can't forcibly eject devices form power domain,
+		 * so we can't really remove power domains once they
+		 * were added.
+		 */
+		.suppress_bind_attrs = true,
+	},
+};
+
+static int __init rockchip_pm_domain_drv_register(void)
+{
+	return platform_driver_register(&rockchip_pm_domain_driver);
+}
+postcore_initcall(rockchip_pm_domain_drv_register);