soc: apple: Add driver for Apple PMGR power state controls (6df9d38f) · Commits · github.com / kvm-riscv / linux

drivers/soc/Kconfig

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		@@ -3,6 +3,7 @@ menu "SOC (System On Chip) specific Drivers"

		source "drivers/soc/actions/Kconfig"
		source "drivers/soc/amlogic/Kconfig"
		source "drivers/soc/apple/Kconfig"
		source "drivers/soc/aspeed/Kconfig"
		source "drivers/soc/atmel/Kconfig"
		source "drivers/soc/bcm/Kconfig"

drivers/soc/Makefile

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		@@ -4,6 +4,7 @@
		#

		obj-$(CONFIG_ARCH_ACTIONS) += actions/
		obj-$(CONFIG_ARCH_APPLE) += apple/
		obj-y += aspeed/
		obj-$(CONFIG_ARCH_AT91) += atmel/
		obj-y += bcm/

drivers/soc/apple/Kconfig

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		# SPDX-License-Identifier: GPL-2.0-only

		if ARCH_APPLE \|\| COMPILE_TEST

		menu "Apple SoC drivers"

		config APPLE_PMGR_PWRSTATE
		tristate "Apple SoC PMGR power state control"
		depends on PM
		select REGMAP
		select MFD_SYSCON
		select PM_GENERIC_DOMAINS
		select RESET_CONTROLLER
		default ARCH_APPLE
		help
		The PMGR block in Apple SoCs provides high-level power state
		controls for SoC devices. This driver manages them through the
		generic power domain framework, and also provides reset support.

		endmenu

		endif

drivers/soc/apple/Makefile

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		# SPDX-License-Identifier: GPL-2.0-only
		obj-$(CONFIG_APPLE_PMGR_PWRSTATE) += apple-pmgr-pwrstate.o

drivers/soc/apple/apple-pmgr-pwrstate.c

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		// SPDX-License-Identifier: GPL-2.0-only OR MIT
		/*
		* Apple SoC PMGR device power state driver
		*
		* Copyright The Asahi Linux Contributors
		*/

		#include <linux/bitops.h>
		#include <linux/bitfield.h>
		#include <linux/err.h>
		#include <linux/of.h>
		#include <linux/of_address.h>
		#include <linux/platform_device.h>
		#include <linux/pm_domain.h>
		#include <linux/regmap.h>
		#include <linux/mfd/syscon.h>
		#include <linux/reset-controller.h>
		#include <linux/module.h>

		#define APPLE_PMGR_RESET BIT(31)
		#define APPLE_PMGR_AUTO_ENABLE BIT(28)
		#define APPLE_PMGR_PS_AUTO GENMASK(27, 24)
		#define APPLE_PMGR_PARENT_OFF BIT(11)
		#define APPLE_PMGR_DEV_DISABLE BIT(10)
		#define APPLE_PMGR_WAS_CLKGATED BIT(9)
		#define APPLE_PMGR_WAS_PWRGATED BIT(8)
		#define APPLE_PMGR_PS_ACTUAL GENMASK(7, 4)
		#define APPLE_PMGR_PS_TARGET GENMASK(3, 0)

		#define APPLE_PMGR_FLAGS (APPLE_PMGR_WAS_CLKGATED \| APPLE_PMGR_WAS_PWRGATED)

		#define APPLE_PMGR_PS_ACTIVE 0xf
		#define APPLE_PMGR_PS_CLKGATE 0x4
		#define APPLE_PMGR_PS_PWRGATE 0x0

		#define APPLE_PMGR_PS_SET_TIMEOUT 100
		#define APPLE_PMGR_RESET_TIME 1

		struct apple_pmgr_ps {
		struct device *dev;
		struct generic_pm_domain genpd;
		struct reset_controller_dev rcdev;
		struct regmap *regmap;
		u32 offset;
		};

		#define genpd_to_apple_pmgr_ps(_genpd) container_of(_genpd, struct apple_pmgr_ps, genpd)
		#define rcdev_to_apple_pmgr_ps(_rcdev) container_of(_rcdev, struct apple_pmgr_ps, rcdev)

		static int apple_pmgr_ps_set(struct generic_pm_domain *genpd, u32 pstate, bool auto_enable)
		{
		int ret;
		struct apple_pmgr_ps *ps = genpd_to_apple_pmgr_ps(genpd);
		u32 reg;

		ret = regmap_read(ps->regmap, ps->offset, &reg);
		if (ret < 0)
		return ret;

		/* Resets are synchronous, and only work if the device is powered and clocked. */
		if (reg & APPLE_PMGR_RESET && pstate != APPLE_PMGR_PS_ACTIVE)
		dev_err(ps->dev, "PS %s: powering off with RESET active\n",
		genpd->name);

		reg &= ~(APPLE_PMGR_AUTO_ENABLE \| APPLE_PMGR_FLAGS \| APPLE_PMGR_PS_TARGET);
		reg \|= FIELD_PREP(APPLE_PMGR_PS_TARGET, pstate);

		dev_dbg(ps->dev, "PS %s: pwrstate = 0x%x: 0x%x\n", genpd->name, pstate, reg);

		regmap_write(ps->regmap, ps->offset, reg);

		ret = regmap_read_poll_timeout_atomic(
		ps->regmap, ps->offset, reg,
		(FIELD_GET(APPLE_PMGR_PS_ACTUAL, reg) == pstate), 1,
		APPLE_PMGR_PS_SET_TIMEOUT);
		if (ret < 0)
		dev_err(ps->dev, "PS %s: Failed to reach power state 0x%x (now: 0x%x)\n",
		genpd->name, pstate, reg);

		if (auto_enable) {
		/* Not all devices implement this; this is a no-op where not implemented. */
		reg &= ~APPLE_PMGR_FLAGS;
		reg \|= APPLE_PMGR_AUTO_ENABLE;
		regmap_write(ps->regmap, ps->offset, reg);
		}

		return ret;
		}

		static bool apple_pmgr_ps_is_active(struct apple_pmgr_ps *ps)
		{
		u32 reg = 0;

		regmap_read(ps->regmap, ps->offset, &reg);
		/*
		* We consider domains as active if they are actually on, or if they have auto-PM
		* enabled and the intended target is on.
		*/
		return (FIELD_GET(APPLE_PMGR_PS_ACTUAL, reg) == APPLE_PMGR_PS_ACTIVE \|\|
		(FIELD_GET(APPLE_PMGR_PS_TARGET, reg) == APPLE_PMGR_PS_ACTIVE &&
		reg & APPLE_PMGR_AUTO_ENABLE));
		}

		static int apple_pmgr_ps_power_on(struct generic_pm_domain *genpd)
		{
		return apple_pmgr_ps_set(genpd, APPLE_PMGR_PS_ACTIVE, true);
		}

		static int apple_pmgr_ps_power_off(struct generic_pm_domain *genpd)
		{
		return apple_pmgr_ps_set(genpd, APPLE_PMGR_PS_PWRGATE, false);
		}

		static int apple_pmgr_reset_assert(struct reset_controller_dev *rcdev, unsigned long id)
		{
		struct apple_pmgr_ps *ps = rcdev_to_apple_pmgr_ps(rcdev);

		mutex_lock(&ps->genpd.mlock);

		if (ps->genpd.status == GENPD_STATE_OFF)
		dev_err(ps->dev, "PS 0x%x: asserting RESET while powered down\n", ps->offset);

		dev_dbg(ps->dev, "PS 0x%x: assert reset\n", ps->offset);
		/* Quiesce device before asserting reset */
		regmap_update_bits(ps->regmap, ps->offset, APPLE_PMGR_FLAGS \| APPLE_PMGR_DEV_DISABLE,
		APPLE_PMGR_DEV_DISABLE);
		regmap_update_bits(ps->regmap, ps->offset, APPLE_PMGR_FLAGS \| APPLE_PMGR_RESET,
		APPLE_PMGR_RESET);

		mutex_unlock(&ps->genpd.mlock);

		return 0;
		}

		static int apple_pmgr_reset_deassert(struct reset_controller_dev *rcdev, unsigned long id)
		{
		struct apple_pmgr_ps *ps = rcdev_to_apple_pmgr_ps(rcdev);

		mutex_lock(&ps->genpd.mlock);

		dev_dbg(ps->dev, "PS 0x%x: deassert reset\n", ps->offset);
		regmap_update_bits(ps->regmap, ps->offset, APPLE_PMGR_FLAGS \| APPLE_PMGR_RESET, 0);
		regmap_update_bits(ps->regmap, ps->offset, APPLE_PMGR_FLAGS \| APPLE_PMGR_DEV_DISABLE, 0);

		if (ps->genpd.status == GENPD_STATE_OFF)
		dev_err(ps->dev, "PS 0x%x: RESET was deasserted while powered down\n", ps->offset);

		mutex_unlock(&ps->genpd.mlock);

		return 0;
		}

		static int apple_pmgr_reset_reset(struct reset_controller_dev *rcdev, unsigned long id)
		{
		int ret;

		ret = apple_pmgr_reset_assert(rcdev, id);
		if (ret)
		return ret;

		usleep_range(APPLE_PMGR_RESET_TIME, 2 * APPLE_PMGR_RESET_TIME);

		return apple_pmgr_reset_deassert(rcdev, id);
		}

		static int apple_pmgr_reset_status(struct reset_controller_dev *rcdev, unsigned long id)
		{
		struct apple_pmgr_ps *ps = rcdev_to_apple_pmgr_ps(rcdev);
		u32 reg = 0;

		regmap_read(ps->regmap, ps->offset, &reg);

		return !!(reg & APPLE_PMGR_RESET);
		}

		const struct reset_control_ops apple_pmgr_reset_ops = {
		.assert = apple_pmgr_reset_assert,
		.deassert = apple_pmgr_reset_deassert,
		.reset = apple_pmgr_reset_reset,
		.status = apple_pmgr_reset_status,
		};

		static int apple_pmgr_reset_xlate(struct reset_controller_dev *rcdev,
		const struct of_phandle_args *reset_spec)
		{
		return 0;
		}

		static int apple_pmgr_ps_probe(struct platform_device *pdev)
		{
		struct device *dev = &pdev->dev;
		struct device_node *node = dev->of_node;
		struct apple_pmgr_ps *ps;
		struct regmap *regmap;
		struct of_phandle_iterator it;
		int ret;
		const char *name;
		bool active;

		regmap = syscon_node_to_regmap(node->parent);
		if (IS_ERR(regmap))
		return PTR_ERR(regmap);

		ps = devm_kzalloc(dev, sizeof(*ps), GFP_KERNEL);
		if (!ps)
		return -ENOMEM;

		ps->dev = dev;
		ps->regmap = regmap;

		ret = of_property_read_string(node, "label", &name);
		if (ret < 0) {
		dev_err(dev, "missing label property\n");
		return ret;
		}

		ret = of_property_read_u32(node, "reg", &ps->offset);
		if (ret < 0) {
		dev_err(dev, "missing reg property\n");
		return ret;
		}

		ps->genpd.name = name;
		ps->genpd.power_on = apple_pmgr_ps_power_on;
		ps->genpd.power_off = apple_pmgr_ps_power_off;

		active = apple_pmgr_ps_is_active(ps);
		if (of_property_read_bool(node, "apple,always-on")) {
		ps->genpd.flags \|= GENPD_FLAG_ALWAYS_ON;
		if (!active) {
		dev_warn(dev, "always-on domain %s is not on at boot\n", name);
		/* Turn it on so pm_genpd_init does not fail */
		active = apple_pmgr_ps_power_on(&ps->genpd) == 0;
		}
		}

		/* Turn on auto-PM if the domain is already on */
		if (active)
		regmap_update_bits(regmap, ps->offset, APPLE_PMGR_FLAGS \| APPLE_PMGR_AUTO_ENABLE,
		APPLE_PMGR_AUTO_ENABLE);

		ret = pm_genpd_init(&ps->genpd, NULL, !active);
		if (ret < 0) {
		dev_err(dev, "pm_genpd_init failed\n");
		return ret;
		}

		ret = of_genpd_add_provider_simple(node, &ps->genpd);
		if (ret < 0) {
		dev_err(dev, "of_genpd_add_provider_simple failed\n");
		return ret;
		}

		of_for_each_phandle(&it, ret, node, "power-domains", "#power-domain-cells", -1) {
		struct of_phandle_args parent, child;

		parent.np = it.node;
		parent.args_count = of_phandle_iterator_args(&it, parent.args, MAX_PHANDLE_ARGS);
		child.np = node;
		child.args_count = 0;
		ret = of_genpd_add_subdomain(&parent, &child);

		if (ret == -EPROBE_DEFER) {
		of_node_put(parent.np);
		goto err_remove;
		} else if (ret < 0) {
		dev_err(dev, "failed to add to parent domain: %d (%s -> %s)\n",
		ret, it.node->name, node->name);
		of_node_put(parent.np);
		goto err_remove;
		}
		}

		/*
		* Do not participate in regular PM; parent power domains are handled via the
		* genpd hierarchy.
		*/
		pm_genpd_remove_device(dev);

		ps->rcdev.owner = THIS_MODULE;
		ps->rcdev.nr_resets = 1;
		ps->rcdev.ops = &apple_pmgr_reset_ops;
		ps->rcdev.of_node = dev->of_node;
		ps->rcdev.of_reset_n_cells = 0;
		ps->rcdev.of_xlate = apple_pmgr_reset_xlate;

		ret = devm_reset_controller_register(dev, &ps->rcdev);
		if (ret < 0)
		goto err_remove;

		return 0;
		err_remove:
		of_genpd_del_provider(node);
		pm_genpd_remove(&ps->genpd);
		return ret;
		}

		static const struct of_device_id apple_pmgr_ps_of_match[] = {
		{ .compatible = "apple,pmgr-pwrstate" },
		{}
		};

		MODULE_DEVICE_TABLE(of, apple_pmgr_ps_of_match);

		static struct platform_driver apple_pmgr_ps_driver = {
		.probe = apple_pmgr_ps_probe,
		.driver = {
		.name = "apple-pmgr-pwrstate",
		.of_match_table = apple_pmgr_ps_of_match,
		},
		};

		MODULE_AUTHOR("Hector Martin <marcan@marcan.st>");
		MODULE_DESCRIPTION("PMGR power state driver for Apple SoCs");
		MODULE_LICENSE("GPL v2");

		module_platform_driver(apple_pmgr_ps_driver);