On 05/10/2021 17:59, Hector Martin wrote:
> 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 (auto-pm,
> clockgate-only state), 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.
>
> Signed-off-by: Hector Martin <marcan@xxxxxxxxx>
> ---
> MAINTAINERS | 1 +
> 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 | 281 ++++++++++++++++++++++++
> 6 files changed, 307 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/MAINTAINERS b/MAINTAINERS
> index 5fe53d9a2956..def5e05da2bc 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1725,6 +1725,7 @@ F: Documentation/devicetree/bindings/pinctrl/apple,pinctrl.yaml
> F: Documentation/devicetree/bindings/power/apple*
> F: arch/arm64/boot/dts/apple/
> F: drivers/irqchip/irq-apple-aic.c
> +F: drivers/soc/apple/*
> F: include/dt-bindings/interrupt-controller/apple-aic.h
> F: include/dt-bindings/pinctrl/apple.h
>
> 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..a0338dbb29b8
> --- /dev/null
> +++ b/drivers/soc/apple/apple-pmgr-pwrstate.c
> @@ -0,0 +1,281 @@
> +// 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_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)
> +{
> + int ret;
> + struct apple_pmgr_ps *ps = genpd_to_apple_pmgr_ps(genpd);
> + u32 reg;
> +
> + regmap_read(ps->regmap, ps->offset, ®);
MMIO accesses should not fail, but regmap API could fail if for example
clk_enable() fails. In such case you will write below value based on
random stack init. Please check the return value here.
> +
> + /* 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 0x%x: powering off with RESET active\n", ps->offset);
> +
> + reg &= ~(APPLE_PMGR_AUTO_ENABLE | APPLE_PMGR_WAS_CLKGATED | APPLE_PMGR_WAS_PWRGATED |
> + APPLE_PMGR_PS_TARGET);
> + reg |= FIELD_PREP(APPLE_PMGR_PS_TARGET, pstate);
> +
> + dev_dbg(ps->dev, "PS 0x%x: pwrstate = 0x%x: 0x%x\n", ps->offset, 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 0x%x: Failed to reach power state 0x%x (now: 0x%x)\n",
> + ps->offset, pstate, reg);
> + return ret;
> +}
> +
> +static bool apple_pmgr_ps_is_active(struct apple_pmgr_ps *ps)
> +{
> + u32 reg;
> +
> + regmap_read(ps->regmap, ps->offset, ®);
Check the return value or initialize reg to 0.
> + return FIELD_GET(APPLE_PMGR_PS_ACTUAL, reg) == APPLE_PMGR_PS_ACTIVE;
> +}
> +
> +static int apple_pmgr_ps_power_on(struct generic_pm_domain *genpd)
> +{
> + return apple_pmgr_ps_set(genpd, APPLE_PMGR_PS_ACTIVE);
> +}
> +
> +static int apple_pmgr_ps_power_off(struct generic_pm_domain *genpd)
> +{
> + return apple_pmgr_ps_set(genpd, APPLE_PMGR_PS_PWRGATE);
> +}
> +
> +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_set_bits(ps->regmap, ps->offset, APPLE_PMGR_DEV_DISABLE);
> + regmap_set_bits(ps->regmap, ps->offset, 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);
This looks wrong: it can be a spin-lock, not mutex, so you should use
genpd_lock.
However now I wonder if there could be a case when a reset-controller
consumer calls it from it's GENPD_NOTIFY_ON notifier? In such case you
would have this lock taken.
> +
> + dev_dbg(ps->dev, "PS 0x%x: deassert reset\n", ps->offset);
> + regmap_clear_bits(ps->regmap, ps->offset, APPLE_PMGR_RESET);
> + regmap_clear_bits(ps->regmap, ps->offset, APPLE_PMGR_DEV_DISABLE);
> +
> + 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;
> +
> + 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;
> +
> + 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, "apple,domain-name", &name);
> + if (ret < 0) {
> + dev_err(dev, "missing apple,domain-name 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;
> + }
> +
> + if (of_property_read_bool(node, "apple,always-on"))
> + ps->genpd.flags |= GENPD_FLAG_ALWAYS_ON;
> +
> + ps->genpd.name = name;
> + ps->genpd.power_on = apple_pmgr_ps_power_on;
> + ps->genpd.power_off = apple_pmgr_ps_power_off;
> +
> + ret = pm_genpd_init(&ps->genpd, NULL, !apple_pmgr_ps_is_active(ps));
> + 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;
> + }
> + }
> +
> + 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,t8103-pmgr-pwrstate" },
> + { .compatible = "apple,pmgr-pwrstate" },
You call the device/driver "pwrstate", which it seems is "power state".
These are not power states. These are power controllers or power
domains. Power state is rather a state of power domain - e.g. on or
gated. How about renaming it to power domain or pd?
> + {}
> +};
> +
> +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@xxxxxxxxx>");
> +MODULE_DESCRIPTION("PMGR power state driver for Apple SoCs");
> +MODULE_LICENSE("GPL v2");
> +
> +module_platform_driver(apple_pmgr_ps_driver);
>
Best regards,
Krzysztof
