// 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_PS_MIN GENMASK(19, 16)
#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;
u32 min_state;
};
#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, ®);
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, ®);
/*
* 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);
unsigned long flags;
spin_lock_irqsave(&ps->genpd.slock, flags);
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);
spin_unlock_irqrestore(&ps->genpd.slock, flags);
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);
unsigned long flags;
spin_lock_irqsave(&ps->genpd.slock, flags);
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);
spin_unlock_irqrestore(&ps->genpd.slock, flags);
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, ®);
return !!(reg & APPLE_PMGR_RESET);
}
static 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.flags |= GENPD_FLAG_IRQ_SAFE;
ps->genpd.name = name;
ps->genpd.power_on = apple_pmgr_ps_power_on;
ps->genpd.power_off = apple_pmgr_ps_power_off;
ret = of_property_read_u32(node, "apple,min-state", &ps->min_state);
if (ret == 0 && ps->min_state <= APPLE_PMGR_PS_ACTIVE)
regmap_update_bits(regmap, ps->offset, APPLE_PMGR_FLAGS | APPLE_PMGR_PS_MIN,
FIELD_PREP(APPLE_PMGR_PS_MIN, ps->min_state));
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 <[email protected]>");
MODULE_DESCRIPTION("PMGR power state driver for Apple SoCs");
module_platform_driver(apple_pmgr_ps_driver);
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