pmdomain: apple: Add PMP reporting interface

This driver manages a shared SRAM area that is used to communicate
desired power states of devices that PMP manages.

Signed-off-by: Sasha Finkelstein <fnkl.kernel@gmail.com>

Author: WhatAmISupposedToPutHere

drivers/pmdomain/apple/Makefile

@@ -1,2 +1,3 @@
 # SPDX-License-Identifier: GPL-2.0-only
 obj-$(CONFIG_APPLE_PMGR_PWRSTATE)	+= pmgr-pwrstate.o
+obj-$(CONFIG_APPLE_PMP)	+= pmp-report.o

drivers/pmdomain/apple/pmp-report.c

@@ -0,0 +1,235 @@
+// SPDX-License-Identifier: GPL-2.0-only OR MIT
+/*
+ * Apple SoC PMP power state reporting driver
+ *
+ * Copyright The Asahi Linux Contributors
+ */
+
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/pm_domain.h>
+
+#define PMP_REPORT_READY 0x1
+
+struct apple_pmp_report_offsets {
+	u32 tgt_read;
+	u32 tgt_write;
+	u32 actual;
+	u32 status;
+};
+
+struct apple_pmp_report {
+	struct device *dev;
+	const struct apple_pmp_report_offsets *offsets;
+	void __iomem *base;
+	spinlock_t lock;
+};
+
+static int apple_pmp_report_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct apple_pmp_report *rep;
+	int ret;
+
+	rep = devm_kzalloc(dev, sizeof(*rep), GFP_KERNEL);
+	if (!rep)
+		return -ENOMEM;
+
+	rep->dev = dev;
+	rep->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(rep->base))
+		return PTR_ERR(rep->base);
+	rep->offsets = of_device_get_match_data(dev);
+	dev_set_drvdata(dev, rep);
+	ret = of_platform_populate(np, NULL, NULL, dev);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to create child devices\n");
+
+	return 0;
+}
+
+static const struct apple_pmp_report_offsets apple_pmp_offsets_t600x = {
+	.tgt_read = 0xf80,
+	.tgt_write = 0x107c0,
+	.actual = 0x1000,
+	.status = 0x10,
+};
+
+static const struct apple_pmp_report_offsets apple_pmp_offsets_t602x = {
+	.tgt_read = 0x2000,
+	.tgt_write = 0x11000,
+	.actual = 0x2080,
+	.status = 0x10,
+};
+
+static const struct apple_pmp_report_offsets apple_pmp_offsets_t8112 = {
+	.tgt_read = 0xa00,
+	.tgt_write = 0x10500,
+	.actual = 0xa40,
+	.status = 0x10,
+};
+
+static const struct of_device_id apple_pmp_report_of_match[] = {
+	{ .compatible = "apple,t6000-pmp-v2-report", .data = &apple_pmp_offsets_t600x },
+	{ .compatible = "apple,t6020-pmp-v2-report", .data = &apple_pmp_offsets_t602x },
+	{ .compatible = "apple,t8112-pmp-v2-report", .data = &apple_pmp_offsets_t8112 },
+	{}
+};
+
+static struct platform_driver apple_pmp_report_driver = {
+	.probe = apple_pmp_report_probe,
+	.driver = {
+		.name = "apple-pmp-report",
+		.of_match_table = apple_pmp_report_of_match,
+	},
+};
+
+struct apple_pmp_report_entry {
+	struct device *dev;
+	struct generic_pm_domain genpd;
+	u32 id;
+};
+
+#define genpd_to_apple_pmp_report_entry(_genpd) \
+	container_of(_genpd, struct apple_pmp_report_entry, genpd)
+
+static int apple_pmp_report_set_state(struct generic_pm_domain *genpd, bool enable)
+{
+	struct apple_pmp_report_entry *ent = genpd_to_apple_pmp_report_entry(genpd);
+	struct apple_pmp_report *rep = dev_get_drvdata(ent->dev->parent);
+	u64 bit_val = 1 << ent->id;
+	u64 val;
+	unsigned long flags;
+
+	spin_lock_irqsave(&rep->lock, flags);
+	val = readq(rep->base + rep->offsets->tgt_read);
+	val &= ~bit_val;
+	if (enable)
+		val |= bit_val;
+	writeq(val, rep->base + rep->offsets->tgt_write);
+	spin_unlock_irqrestore(&rep->lock, flags);
+	val = readq(rep->base + rep->offsets->status);
+	if ((val & PMP_REPORT_READY) == 0)
+		return 0;
+	return readq_poll_timeout_atomic(
+		rep->base + rep->offsets->actual,
+		val,
+		!!(val & bit_val) == !!enable,
+		100,
+		50000);
+}
+
+static int apple_pmp_report_entry_power_on(struct generic_pm_domain *genpd)
+{
+	return apple_pmp_report_set_state(genpd, true);
+}
+
+static int apple_pmp_report_entry_power_off(struct generic_pm_domain *genpd)
+{
+	return apple_pmp_report_set_state(genpd, false);
+}
+
+static int apple_pmp_report_entry_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *node = dev->of_node;
+	struct apple_pmp_report_entry *ent;
+	int ret;
+	const char *name;
+	struct of_phandle_iterator it;
+
+	ent = devm_kzalloc(dev, sizeof(*ent), GFP_KERNEL);
+	if (!ent)
+		return -ENOMEM;
+
+	ent->dev = dev;
+
+	ret = of_property_read_u32(node, "reg", &ent->id);
+	if (ret)
+		return dev_err_probe(dev, ret, "missing reg property\n");
+
+	ret = of_property_read_string(node, "label", &name);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "missing label property\n");
+
+	if (of_property_read_bool(node, "apple,always-on"))
+		ent->genpd.flags |= GENPD_FLAG_ACTIVE_WAKEUP;
+	ent->genpd.name = name;
+	ent->genpd.power_on = apple_pmp_report_entry_power_on;
+	ent->genpd.power_off = apple_pmp_report_entry_power_off;
+
+	ret = pm_genpd_init(&ent->genpd, NULL, true);
+	if (ret)
+		return dev_err_probe(dev, ret, "pm_genpd_init failed\n");
+
+	ret = of_genpd_add_provider_simple(node, &ent->genpd);
+	if (ret)
+		return dev_err_probe(dev, ret, "of_genpd_add_provider_simple failed\n");
+
+	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);
+
+	return 0;
+err_remove:
+	of_genpd_del_provider(node);
+	pm_genpd_remove(&ent->genpd);
+	return ret;
+}
+
+static const struct of_device_id apple_pmp_report_entry_of_match[] = {
+	{ .compatible = "apple,t6000-pmp-v2-report-entry" },
+	{}
+};
+
+static struct platform_driver apple_pmp_report_entry_driver = {
+	.probe = apple_pmp_report_entry_probe,
+	.driver = {
+		.name = "apple-pmp-report-entry",
+		.of_match_table = apple_pmp_report_entry_of_match,
+	},
+};
+
+MODULE_DEVICE_TABLE(of, apple_pmp_report_of_match);
+MODULE_DEVICE_TABLE(of, apple_pmp_report_entry_of_match);
+
+static int __init apple_pmp_report_init(void)
+{
+	platform_driver_register(&apple_pmp_report_entry_driver);
+	platform_driver_register(&apple_pmp_report_driver);
+	return 0;
+}
+
+static void __exit apple_pmp_report_exit(void)
+{
+	platform_driver_unregister(&apple_pmp_report_entry_driver);
+	platform_driver_unregister(&apple_pmp_report_driver);
+}
+
+module_init(apple_pmp_report_init);
+module_exit(apple_pmp_report_exit);
+
+MODULE_DESCRIPTION("PMP power state reporting driver for Apple SoCs");