[PATCH v3 08/11] soc: apple: Add driver for Apple PMGR power state controls
Hector Martin
marcan at marcan.st
Tue Nov 23 23:34:18 PST 2021
Implements genpd and reset providers for downstream devices. Each
instance of the driver binds to a single register and represents a
single SoC power domain.
The driver does not currently implement all features (clockgate-only
state, misc flags), but we declare the respective registers for
documentation purposes. These features will be added as they become
useful for downstream devices.
This also creates the apple/soc tree and Kconfig submenu.
Acked-by: Linus Walleij <linus.walleij at linaro.org>
Signed-off-by: Hector Martin <marcan at marcan.st>
---
drivers/soc/Kconfig | 1 +
drivers/soc/Makefile | 1 +
drivers/soc/apple/Kconfig | 21 ++
drivers/soc/apple/Makefile | 2 +
drivers/soc/apple/apple-pmgr-pwrstate.c | 317 ++++++++++++++++++++++++
5 files changed, 342 insertions(+)
create mode 100644 drivers/soc/apple/Kconfig
create mode 100644 drivers/soc/apple/Makefile
create mode 100644 drivers/soc/apple/apple-pmgr-pwrstate.c
diff --git a/drivers/soc/Kconfig b/drivers/soc/Kconfig
index e8a30c4c5aec..a8562678c437 100644
--- a/drivers/soc/Kconfig
+++ b/drivers/soc/Kconfig
@@ -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"
diff --git a/drivers/soc/Makefile b/drivers/soc/Makefile
index a05e9fbcd3e0..adb30c2d4fea 100644
--- a/drivers/soc/Makefile
+++ b/drivers/soc/Makefile
@@ -4,6 +4,7 @@
#
obj-$(CONFIG_ARCH_ACTIONS) += actions/
+obj-$(CONFIG_ARCH_APPLE) += apple/
obj-y += aspeed/
obj-$(CONFIG_ARCH_AT91) += atmel/
obj-y += bcm/
diff --git a/drivers/soc/apple/Kconfig b/drivers/soc/apple/Kconfig
new file mode 100644
index 000000000000..271092b6aee7
--- /dev/null
+++ b/drivers/soc/apple/Kconfig
@@ -0,0 +1,21 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+if ARCH_APPLE || COMPILE_TEST
+
+menu "Apple SoC drivers"
+
+config APPLE_PMGR_PWRSTATE
+ tristate "Apple SoC PMGR power state control"
+ select REGMAP
+ select MFD_SYSCON
+ select PM_GENERIC_DOMAINS
+ select RESET_CONTROLLER
+ default ARCH_APPLE
+ help
+ The PMGR block in Apple SoCs provides high-level power state
+ controls for SoC devices. This driver manages them through the
+ generic power domain framework, and also provides reset support.
+
+endmenu
+
+endif
diff --git a/drivers/soc/apple/Makefile b/drivers/soc/apple/Makefile
new file mode 100644
index 000000000000..c114e84667e4
--- /dev/null
+++ b/drivers/soc/apple/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_APPLE_PMGR_PWRSTATE) += apple-pmgr-pwrstate.o
diff --git a/drivers/soc/apple/apple-pmgr-pwrstate.c b/drivers/soc/apple/apple-pmgr-pwrstate.c
new file mode 100644
index 000000000000..8ad9d5fdefbf
--- /dev/null
+++ b/drivers/soc/apple/apple-pmgr-pwrstate.c
@@ -0,0 +1,317 @@
+// 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, ®);
+ 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);
+
+ 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, ®);
+
+ 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 at marcan.st>");
+MODULE_DESCRIPTION("PMGR power state driver for Apple SoCs");
+MODULE_LICENSE("GPL v2");
+
+module_platform_driver(apple_pmgr_ps_driver);
--
2.33.0
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