1 files changed, 473 insertions, 0 deletions
diff --git a/drivers/acpi/acpi_tad.c b/drivers/acpi/acpi_tad.c
new file mode 100644
index 000000000000..e99c4ed7e677
--- /dev/null
+++ b/drivers/acpi/acpi_tad.c
@@ -0,0 +1,473 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ACPI Time and Alarm (TAD) Device Driver
+ *
+ * Copyright (C) 2018 Intel Corporation
+ * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+ *
+ * This driver is based on Section 9.18 of the ACPI 6.2 specification revision.
+ *
+ * It only supports the system wakeup capabilities of the TAD.
+ *
+ * Provided are sysfs attributes, available under the TAD platform device,
+ * allowing user space to manage the AC and DC wakeup timers of the TAD:
+ * set and read their values, set and check their expire timer wake policies,
+ * check and clear their status and check the capabilities of the TAD reported
+ * by AML.  The DC timer attributes are only present if the TAD supports a
+ * separate DC alarm timer.
+ *
+ * The wakeup events handling and power management of the TAD is expected to
+ * be taken care of by the ACPI PM domain attached to its platform device.
+ */
+
+#include <linux/acpi.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/suspend.h>
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Rafael J. Wysocki");
+
+/* ACPI TAD capability flags (ACPI 6.2, Section 9.18.2) */
+#define ACPI_TAD_AC_WAKE	BIT(0)
+#define ACPI_TAD_DC_WAKE	BIT(1)
+#define ACPI_TAD_RT		BIT(2)
+#define ACPI_TAD_RT_IN_MS	BIT(3)
+#define ACPI_TAD_S4_S5__GWS	BIT(4)
+#define ACPI_TAD_AC_S4_WAKE	BIT(5)
+#define ACPI_TAD_AC_S5_WAKE	BIT(6)
+#define ACPI_TAD_DC_S4_WAKE	BIT(7)
+#define ACPI_TAD_DC_S5_WAKE	BIT(8)
+
+/* ACPI TAD alarm timer selection */
+#define ACPI_TAD_AC_TIMER	(u32)0
+#define ACPI_TAD_DC_TIMER	(u32)1
+
+/* Special value for disabled timer or expired timer wake policy. */
+#define ACPI_TAD_WAKE_DISABLED	(~(u32)0)
+
+struct acpi_tad_driver_data {
+	u32 capabilities;
+};
+
+static int acpi_tad_wake_set(struct device *dev, char *method, u32 timer_id,
+			     u32 value)
+{
+	acpi_handle handle = ACPI_HANDLE(dev);
+	union acpi_object args[] = {
+		{ .type = ACPI_TYPE_INTEGER, },
+		{ .type = ACPI_TYPE_INTEGER, },
+	};
+	struct acpi_object_list arg_list = {
+		.pointer = args,
+		.count = ARRAY_SIZE(args),
+	};
+	unsigned long long retval;
+	acpi_status status;
+
+	args[0].integer.value = timer_id;
+	args[1].integer.value = value;
+
+	pm_runtime_get_sync(dev);
+
+	status = acpi_evaluate_integer(handle, method, &arg_list, &retval);
+
+	pm_runtime_put_sync(dev);
+
+	if (ACPI_FAILURE(status) || retval)
+		return -EIO;
+
+	return 0;
+}
+
+static int acpi_tad_wake_write(struct device *dev, const char *buf, char *method,
+			       u32 timer_id, const char *specval)
+{
+	u32 value;
+
+	if (sysfs_streq(buf, specval)) {
+		value = ACPI_TAD_WAKE_DISABLED;
+	} else {
+		int ret = kstrtou32(buf, 0, &value);
+
+		if (ret)
+			return ret;
+
+		if (value == ACPI_TAD_WAKE_DISABLED)
+			return -EINVAL;
+	}
+
+	return acpi_tad_wake_set(dev, method, timer_id, value);
+}
+
+static ssize_t acpi_tad_wake_read(struct device *dev, char *buf, char *method,
+				  u32 timer_id, const char *specval)
+{
+	acpi_handle handle = ACPI_HANDLE(dev);
+	union acpi_object args[] = {
+		{ .type = ACPI_TYPE_INTEGER, },
+	};
+	struct acpi_object_list arg_list = {
+		.pointer = args,
+		.count = ARRAY_SIZE(args),
+	};
+	unsigned long long retval;
+	acpi_status status;
+
+	args[0].integer.value = timer_id;
+
+	pm_runtime_get_sync(dev);
+
+	status = acpi_evaluate_integer(handle, method, &arg_list, &retval);
+
+	pm_runtime_put_sync(dev);
+
+	if (ACPI_FAILURE(status))
+		return -EIO;
+
+	if ((u32)retval == ACPI_TAD_WAKE_DISABLED)
+		return sprintf(buf, "%s\n", specval);
+
+	return sprintf(buf, "%u\n", (u32)retval);
+}
+
+static const char *alarm_specval = "disabled";
+
+static int acpi_tad_alarm_write(struct device *dev, const char *buf,
+				u32 timer_id)
+{
+	return acpi_tad_wake_write(dev, buf, "_STV", timer_id, alarm_specval);
+}
+
+static ssize_t acpi_tad_alarm_read(struct device *dev, char *buf, u32 timer_id)
+{
+	return acpi_tad_wake_read(dev, buf, "_TIV", timer_id, alarm_specval);
+}
+
+static const char *policy_specval = "never";
+
+static int acpi_tad_policy_write(struct device *dev, const char *buf,
+				 u32 timer_id)
+{
+	return acpi_tad_wake_write(dev, buf, "_STP", timer_id, policy_specval);
+}
+
+static ssize_t acpi_tad_policy_read(struct device *dev, char *buf, u32 timer_id)
+{
+	return acpi_tad_wake_read(dev, buf, "_TIP", timer_id, policy_specval);
+}
+
+static int acpi_tad_clear_status(struct device *dev, u32 timer_id)
+{
+	acpi_handle handle = ACPI_HANDLE(dev);
+	union acpi_object args[] = {
+		{ .type = ACPI_TYPE_INTEGER, },
+	};
+	struct acpi_object_list arg_list = {
+		.pointer = args,
+		.count = ARRAY_SIZE(args),
+	};
+	unsigned long long retval;
+	acpi_status status;
+
+	args[0].integer.value = timer_id;
+
+	pm_runtime_get_sync(dev);
+
+	status = acpi_evaluate_integer(handle, "_CWS", &arg_list, &retval);
+
+	pm_runtime_put_sync(dev);
+
+	if (ACPI_FAILURE(status) || retval)
+		return -EIO;
+
+	return 0;
+}
+
+static int acpi_tad_status_write(struct device *dev, const char *buf, u32 timer_id)
+{
+	int ret, value;
+
+	ret = kstrtoint(buf, 0, &value);
+	if (ret)
+		return ret;
+
+	if (value)
+		return -EINVAL;
+
+	return acpi_tad_clear_status(dev, timer_id);
+}
+
+static ssize_t acpi_tad_status_read(struct device *dev, char *buf, u32 timer_id)
+{
+	acpi_handle handle = ACPI_HANDLE(dev);
+	union acpi_object args[] = {
+		{ .type = ACPI_TYPE_INTEGER, },
+	};
+	struct acpi_object_list arg_list = {
+		.pointer = args,
+		.count = ARRAY_SIZE(args),
+	};
+	unsigned long long retval;
+	acpi_status status;
+
+	args[0].integer.value = timer_id;
+
+	pm_runtime_get_sync(dev);
+
+	status = acpi_evaluate_integer(handle, "_GWS", &arg_list, &retval);
+
+	pm_runtime_put_sync(dev);
+
+	if (ACPI_FAILURE(status))
+		return -EIO;
+
+	return sprintf(buf, "0x%02X\n", (u32)retval);
+}
+
+static ssize_t caps_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct acpi_tad_driver_data *dd = dev_get_drvdata(dev);
+
+	return sprintf(buf, "0x%02X\n", dd->capabilities);
+}
+
+static DEVICE_ATTR_RO(caps);
+
+static ssize_t ac_alarm_store(struct device *dev, struct device_attribute *attr,
+			      const char *buf, size_t count)
+{
+	int ret = acpi_tad_alarm_write(dev, buf, ACPI_TAD_AC_TIMER);
+
+	return ret ? ret : count;
+}
+
+static ssize_t ac_alarm_show(struct device *dev, struct device_attribute *attr,
+			     char *buf)
+{
+	return acpi_tad_alarm_read(dev, buf, ACPI_TAD_AC_TIMER);
+}
+
+static DEVICE_ATTR(ac_alarm, S_IRUSR | S_IWUSR, ac_alarm_show, ac_alarm_store);
+
+static ssize_t ac_policy_store(struct device *dev, struct device_attribute *attr,
+			       const char *buf, size_t count)
+{
+	int ret = acpi_tad_policy_write(dev, buf, ACPI_TAD_AC_TIMER);
+
+	return ret ? ret : count;
+}
+
+static ssize_t ac_policy_show(struct device *dev, struct device_attribute *attr,
+			      char *buf)
+{
+	return acpi_tad_policy_read(dev, buf, ACPI_TAD_AC_TIMER);
+}
+
+static DEVICE_ATTR(ac_policy, S_IRUSR | S_IWUSR, ac_policy_show, ac_policy_store);
+
+static ssize_t ac_status_store(struct device *dev, struct device_attribute *attr,
+			       const char *buf, size_t count)
+{
+	int ret = acpi_tad_status_write(dev, buf, ACPI_TAD_AC_TIMER);
+
+	return ret ? ret : count;
+}
+
+static ssize_t ac_status_show(struct device *dev, struct device_attribute *attr,
+			      char *buf)
+{
+	return acpi_tad_status_read(dev, buf, ACPI_TAD_AC_TIMER);
+}
+
+static DEVICE_ATTR(ac_status, S_IRUSR | S_IWUSR, ac_status_show, ac_status_store);
+
+static struct attribute *acpi_tad_attrs[] = {
+	&dev_attr_caps.attr,
+	&dev_attr_ac_alarm.attr,
+	&dev_attr_ac_policy.attr,
+	&dev_attr_ac_status.attr,
+	NULL,
+};
+static const struct attribute_group acpi_tad_attr_group = {
+	.attrs	= acpi_tad_attrs,
+};
+
+static ssize_t dc_alarm_store(struct device *dev, struct device_attribute *attr,
+			      const char *buf, size_t count)
+{
+	int ret = acpi_tad_alarm_write(dev, buf, ACPI_TAD_DC_TIMER);
+
+	return ret ? ret : count;
+}
+
+static ssize_t dc_alarm_show(struct device *dev, struct device_attribute *attr,
+			     char *buf)
+{
+	return acpi_tad_alarm_read(dev, buf, ACPI_TAD_DC_TIMER);
+}
+
+static DEVICE_ATTR(dc_alarm, S_IRUSR | S_IWUSR, dc_alarm_show, dc_alarm_store);
+
+static ssize_t dc_policy_store(struct device *dev, struct device_attribute *attr,
+			       const char *buf, size_t count)
+{
+	int ret = acpi_tad_policy_write(dev, buf, ACPI_TAD_DC_TIMER);
+
+	return ret ? ret : count;
+}
+
+static ssize_t dc_policy_show(struct device *dev, struct device_attribute *attr,
+			      char *buf)
+{
+	return acpi_tad_policy_read(dev, buf, ACPI_TAD_DC_TIMER);
+}
+
+static DEVICE_ATTR(dc_policy, S_IRUSR | S_IWUSR, dc_policy_show, dc_policy_store);
+
+static ssize_t dc_status_store(struct device *dev, struct device_attribute *attr,
+			       const char *buf, size_t count)
+{
+	int ret = acpi_tad_status_write(dev, buf, ACPI_TAD_DC_TIMER);
+
+	return ret ? ret : count;
+}
+
+static ssize_t dc_status_show(struct device *dev, struct device_attribute *attr,
+			      char *buf)
+{
+	return acpi_tad_status_read(dev, buf, ACPI_TAD_DC_TIMER);
+}
+
+static DEVICE_ATTR(dc_status, S_IRUSR | S_IWUSR, dc_status_show, dc_status_store);
+
+static struct attribute *acpi_tad_dc_attrs[] = {
+	&dev_attr_dc_alarm.attr,
+	&dev_attr_dc_policy.attr,
+	&dev_attr_dc_status.attr,
+	NULL,
+};
+static const struct attribute_group acpi_tad_dc_attr_group = {
+	.attrs	= acpi_tad_dc_attrs,
+};
+
+static int acpi_tad_disable_timer(struct device *dev, u32 timer_id)
+{
+	return acpi_tad_wake_set(dev, "_STV", timer_id, ACPI_TAD_WAKE_DISABLED);
+}
+
+static int acpi_tad_remove(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct acpi_tad_driver_data *dd = dev_get_drvdata(dev);
+
+	device_init_wakeup(dev, false);
+
+	pm_runtime_get_sync(dev);
+
+	if (dd->capabilities & ACPI_TAD_DC_WAKE)
+		sysfs_remove_group(&dev->kobj, &acpi_tad_dc_attr_group);
+
+	sysfs_remove_group(&dev->kobj, &acpi_tad_attr_group);
+
+	acpi_tad_disable_timer(dev, ACPI_TAD_AC_TIMER);
+	acpi_tad_clear_status(dev, ACPI_TAD_AC_TIMER);
+	if (dd->capabilities & ACPI_TAD_DC_WAKE) {
+		acpi_tad_disable_timer(dev, ACPI_TAD_DC_TIMER);
+		acpi_tad_clear_status(dev, ACPI_TAD_DC_TIMER);
+	}
+
+	pm_runtime_put_sync(dev);
+	pm_runtime_disable(dev);
+	return 0;
+}
+
+static int acpi_tad_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	acpi_handle handle = ACPI_HANDLE(dev);
+	struct acpi_tad_driver_data *dd;
+	acpi_status status;
+	unsigned long long caps;
+	int ret;
+
+	/*
+	 * Initialization failure messages are mostly about firmware issues, so
+	 * print them at the "info" level.
+	 */
+	status = acpi_evaluate_integer(handle, "_GCP", NULL, &caps);
+	if (ACPI_FAILURE(status)) {
+		dev_info(dev, "Unable to get capabilities\n");
+		return -ENODEV;
+	}
+
+	if (!(caps & ACPI_TAD_AC_WAKE)) {
+		dev_info(dev, "Unsupported capabilities\n");
+		return -ENODEV;
+	}
+
+	if (!acpi_has_method(handle, "_PRW")) {
+		dev_info(dev, "Missing _PRW\n");
+		return -ENODEV;
+	}
+
+	dd = devm_kzalloc(dev, sizeof(*dd), GFP_KERNEL);
+	if (!dd)
+		return -ENOMEM;
+
+	dd->capabilities = caps;
+	dev_set_drvdata(dev, dd);
+
+	/*
+	 * Assume that the ACPI PM domain has been attached to the device and
+	 * simply enable system wakeup and runtime PM and put the device into
+	 * runtime suspend.  Everything else should be taken care of by the ACPI
+	 * PM domain callbacks.
+	 */
+	device_init_wakeup(dev, true);
+	dev_pm_set_driver_flags(dev, DPM_FLAG_SMART_SUSPEND |
+				     DPM_FLAG_LEAVE_SUSPENDED);
+	/*
+	 * The platform bus type layer tells the ACPI PM domain powers up the
+	 * device, so set the runtime PM status of it to "active".
+	 */
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+	pm_runtime_suspend(dev);
+
+	ret = sysfs_create_group(&dev->kobj, &acpi_tad_attr_group);
+	if (ret)
+		goto fail;
+
+	if (caps & ACPI_TAD_DC_WAKE) {
+		ret = sysfs_create_group(&dev->kobj, &acpi_tad_dc_attr_group);
+		if (ret)
+			goto fail;
+	}
+
+	return 0;
+
+fail:
+	acpi_tad_remove(pdev);
+	return ret;
+}
+
+static const struct acpi_device_id acpi_tad_ids[] = {
+	{"ACPI000E", 0},
+	{}
+};
+
+static struct platform_driver acpi_tad_driver = {
+	.driver = {
+		.name = "acpi-tad",
+		.acpi_match_table = acpi_tad_ids,
+	},
+	.probe = acpi_tad_probe,
+	.remove = acpi_tad_remove,
+};
+MODULE_DEVICE_TABLE(acpi, acpi_tad_ids);
+
+module_platform_driver(acpi_tad_driver);