1 files changed, 526 insertions, 0 deletions

diff --git a/drivers/watchdog/wdat_wdt.c b/drivers/watchdog/wdat_wdt.c
new file mode 100644
index 000000000000..e473e3b23720
--- /dev/null
+++ b/drivers/watchdog/wdat_wdt.c
@@ -0,0 +1,526 @@
+/*
+ * ACPI Hardware Watchdog (WDAT) driver.
+ *
+ * Copyright (C) 2016, Intel Corporation
+ * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/acpi.h>
+#include <linux/ioport.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/watchdog.h>
+
+#define MAX_WDAT_ACTIONS ACPI_WDAT_ACTION_RESERVED
+
+/**
+ * struct wdat_instruction - Single ACPI WDAT instruction
+ * @entry: Copy of the ACPI table instruction
+ * @reg: Register the instruction is accessing
+ * @node: Next instruction in action sequence
+ */
+struct wdat_instruction {
+	struct acpi_wdat_entry entry;
+	void __iomem *reg;
+	struct list_head node;
+};
+
+/**
+ * struct wdat_wdt - ACPI WDAT watchdog device
+ * @pdev: Parent platform device
+ * @wdd: Watchdog core device
+ * @period: How long is one watchdog period in ms
+ * @stopped_in_sleep: Is this watchdog stopped by the firmware in S1-S5
+ * @stopped: Was the watchdog stopped by the driver in suspend
+ * @actions: An array of instruction lists indexed by an action number from
+ *           the WDAT table. There can be %NULL entries for not implemented
+ *           actions.
+ */
+struct wdat_wdt {
+	struct platform_device *pdev;
+	struct watchdog_device wdd;
+	unsigned int period;
+	bool stopped_in_sleep;
+	bool stopped;
+	struct list_head *instructions[MAX_WDAT_ACTIONS];
+};
+
+#define to_wdat_wdt(wdd) container_of(wdd, struct wdat_wdt, wdd)
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+static int wdat_wdt_read(struct wdat_wdt *wdat,
+	 const struct wdat_instruction *instr, u32 *value)
+{
+	const struct acpi_generic_address *gas = &instr->entry.register_region;
+
+	switch (gas->access_width) {
+	case 1:
+		*value = ioread8(instr->reg);
+		break;
+	case 2:
+		*value = ioread16(instr->reg);
+		break;
+	case 3:
+		*value = ioread32(instr->reg);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	dev_dbg(&wdat->pdev->dev, "Read %#x from 0x%08llx\n", *value,
+		gas->address);
+
+	return 0;
+}
+
+static int wdat_wdt_write(struct wdat_wdt *wdat,
+	const struct wdat_instruction *instr, u32 value)
+{
+	const struct acpi_generic_address *gas = &instr->entry.register_region;
+
+	switch (gas->access_width) {
+	case 1:
+		iowrite8((u8)value, instr->reg);
+		break;
+	case 2:
+		iowrite16((u16)value, instr->reg);
+		break;
+	case 3:
+		iowrite32(value, instr->reg);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	dev_dbg(&wdat->pdev->dev, "Wrote %#x to 0x%08llx\n", value,
+		gas->address);
+
+	return 0;
+}
+
+static int wdat_wdt_run_action(struct wdat_wdt *wdat, unsigned int action,
+			       u32 param, u32 *retval)
+{
+	struct wdat_instruction *instr;
+
+	if (action >= ARRAY_SIZE(wdat->instructions))
+		return -EINVAL;
+
+	if (!wdat->instructions[action])
+		return -EOPNOTSUPP;
+
+	dev_dbg(&wdat->pdev->dev, "Running action %#x\n", action);
+
+	/* Run each instruction sequentially */
+	list_for_each_entry(instr, wdat->instructions[action], node) {
+		const struct acpi_wdat_entry *entry = &instr->entry;
+		const struct acpi_generic_address *gas;
+		u32 flags, value, mask, x, y;
+		bool preserve;
+		int ret;
+
+		gas = &entry->register_region;
+
+		preserve = entry->instruction & ACPI_WDAT_PRESERVE_REGISTER;
+		flags = entry->instruction & ~ACPI_WDAT_PRESERVE_REGISTER;
+		value = entry->value;
+		mask = entry->mask;
+
+		switch (flags) {
+		case ACPI_WDAT_READ_VALUE:
+			ret = wdat_wdt_read(wdat, instr, &x);
+			if (ret)
+				return ret;
+			x >>= gas->bit_offset;
+			x &= mask;
+			if (retval)
+				*retval = x == value;
+			break;
+
+		case ACPI_WDAT_READ_COUNTDOWN:
+			ret = wdat_wdt_read(wdat, instr, &x);
+			if (ret)
+				return ret;
+			x >>= gas->bit_offset;
+			x &= mask;
+			if (retval)
+				*retval = x;
+			break;
+
+		case ACPI_WDAT_WRITE_VALUE:
+			x = value & mask;
+			x <<= gas->bit_offset;
+			if (preserve) {
+				ret = wdat_wdt_read(wdat, instr, &y);
+				if (ret)
+					return ret;
+				y = y & ~(mask << gas->bit_offset);
+				x |= y;
+			}
+			ret = wdat_wdt_write(wdat, instr, x);
+			if (ret)
+				return ret;
+			break;
+
+		case ACPI_WDAT_WRITE_COUNTDOWN:
+			x = param;
+			x &= mask;
+			x <<= gas->bit_offset;
+			if (preserve) {
+				ret = wdat_wdt_read(wdat, instr, &y);
+				if (ret)
+					return ret;
+				y = y & ~(mask << gas->bit_offset);
+				x |= y;
+			}
+			ret = wdat_wdt_write(wdat, instr, x);
+			if (ret)
+				return ret;
+			break;
+
+		default:
+			dev_err(&wdat->pdev->dev, "Unknown instruction: %u\n",
+				flags);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+static int wdat_wdt_enable_reboot(struct wdat_wdt *wdat)
+{
+	int ret;
+
+	/*
+	 * WDAT specification says that the watchdog is required to reboot
+	 * the system when it fires. However, it also states that it is
+	 * recommeded to make it configurable through hardware register. We
+	 * enable reboot now if it is configrable, just in case.
+	 */
+	ret = wdat_wdt_run_action(wdat, ACPI_WDAT_SET_REBOOT, 0, NULL);
+	if (ret && ret != -EOPNOTSUPP) {
+		dev_err(&wdat->pdev->dev,
+			"Failed to enable reboot when watchdog triggers\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static void wdat_wdt_boot_status(struct wdat_wdt *wdat)
+{
+	u32 boot_status = 0;
+	int ret;
+
+	ret = wdat_wdt_run_action(wdat, ACPI_WDAT_GET_STATUS, 0, &boot_status);
+	if (ret && ret != -EOPNOTSUPP) {
+		dev_err(&wdat->pdev->dev, "Failed to read boot status\n");
+		return;
+	}
+
+	if (boot_status)
+		wdat->wdd.bootstatus = WDIOF_CARDRESET;
+
+	/* Clear the boot status in case BIOS did not do it */
+	ret = wdat_wdt_run_action(wdat, ACPI_WDAT_SET_STATUS, 0, NULL);
+	if (ret && ret != -EOPNOTSUPP)
+		dev_err(&wdat->pdev->dev, "Failed to clear boot status\n");
+}
+
+static void wdat_wdt_set_running(struct wdat_wdt *wdat)
+{
+	u32 running = 0;
+	int ret;
+
+	ret = wdat_wdt_run_action(wdat, ACPI_WDAT_GET_RUNNING_STATE, 0,
+				  &running);
+	if (ret && ret != -EOPNOTSUPP)
+		dev_err(&wdat->pdev->dev, "Failed to read running state\n");
+
+	if (running)
+		set_bit(WDOG_HW_RUNNING, &wdat->wdd.status);
+}
+
+static int wdat_wdt_start(struct watchdog_device *wdd)
+{
+	return wdat_wdt_run_action(to_wdat_wdt(wdd),
+				   ACPI_WDAT_SET_RUNNING_STATE, 0, NULL);
+}
+
+static int wdat_wdt_stop(struct watchdog_device *wdd)
+{
+	return wdat_wdt_run_action(to_wdat_wdt(wdd),
+				   ACPI_WDAT_SET_STOPPED_STATE, 0, NULL);
+}
+
+static int wdat_wdt_ping(struct watchdog_device *wdd)
+{
+	return wdat_wdt_run_action(to_wdat_wdt(wdd), ACPI_WDAT_RESET, 0, NULL);
+}
+
+static int wdat_wdt_set_timeout(struct watchdog_device *wdd,
+				unsigned int timeout)
+{
+	struct wdat_wdt *wdat = to_wdat_wdt(wdd);
+	unsigned int periods;
+	int ret;
+
+	periods = timeout * 1000 / wdat->period;
+	ret = wdat_wdt_run_action(wdat, ACPI_WDAT_SET_COUNTDOWN, periods, NULL);
+	if (!ret)
+		wdd->timeout = timeout;
+	return ret;
+}
+
+static unsigned int wdat_wdt_get_timeleft(struct watchdog_device *wdd)
+{
+	struct wdat_wdt *wdat = to_wdat_wdt(wdd);
+	u32 periods = 0;
+
+	wdat_wdt_run_action(wdat, ACPI_WDAT_GET_COUNTDOWN, 0, &periods);
+	return periods * wdat->period / 1000;
+}
+
+static const struct watchdog_info wdat_wdt_info = {
+	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+	.firmware_version = 0,
+	.identity = "wdat_wdt",
+};
+
+static const struct watchdog_ops wdat_wdt_ops = {
+	.owner = THIS_MODULE,
+	.start = wdat_wdt_start,
+	.stop = wdat_wdt_stop,
+	.ping = wdat_wdt_ping,
+	.set_timeout = wdat_wdt_set_timeout,
+	.get_timeleft = wdat_wdt_get_timeleft,
+};
+
+static int wdat_wdt_probe(struct platform_device *pdev)
+{
+	const struct acpi_wdat_entry *entries;
+	const struct acpi_table_wdat *tbl;
+	struct wdat_wdt *wdat;
+	struct resource *res;
+	void __iomem **regs;
+	acpi_status status;
+	int i, ret;
+
+	status = acpi_get_table(ACPI_SIG_WDAT, 0,
+				(struct acpi_table_header **)&tbl);
+	if (ACPI_FAILURE(status))
+		return -ENODEV;
+
+	wdat = devm_kzalloc(&pdev->dev, sizeof(*wdat), GFP_KERNEL);
+	if (!wdat)
+		return -ENOMEM;
+
+	regs = devm_kcalloc(&pdev->dev, pdev->num_resources, sizeof(*regs),
+			    GFP_KERNEL);
+	if (!regs)
+		return -ENOMEM;
+
+	/* WDAT specification wants to have >= 1ms period */
+	if (tbl->timer_period < 1)
+		return -EINVAL;
+	if (tbl->min_count > tbl->max_count)
+		return -EINVAL;
+
+	wdat->period = tbl->timer_period;
+	wdat->wdd.min_hw_heartbeat_ms = wdat->period * tbl->min_count;
+	wdat->wdd.max_hw_heartbeat_ms = wdat->period * tbl->max_count;
+	wdat->stopped_in_sleep = tbl->flags & ACPI_WDAT_STOPPED;
+	wdat->wdd.info = &wdat_wdt_info;
+	wdat->wdd.ops = &wdat_wdt_ops;
+	wdat->pdev = pdev;
+
+	/* Request and map all resources */
+	for (i = 0; i < pdev->num_resources; i++) {
+		void __iomem *reg;
+
+		res = &pdev->resource[i];
+		if (resource_type(res) == IORESOURCE_MEM) {
+			reg = devm_ioremap_resource(&pdev->dev, res);
+			if (IS_ERR(reg))
+				return PTR_ERR(reg);
+		} else if (resource_type(res) == IORESOURCE_IO) {
+			reg = devm_ioport_map(&pdev->dev, res->start, 1);
+			if (!reg)
+				return -ENOMEM;
+		} else {
+			dev_err(&pdev->dev, "Unsupported resource\n");
+			return -EINVAL;
+		}
+
+		regs[i] = reg;
+	}
+
+	entries = (struct acpi_wdat_entry *)(tbl + 1);
+	for (i = 0; i < tbl->entries; i++) {
+		const struct acpi_generic_address *gas;
+		struct wdat_instruction *instr;
+		struct list_head *instructions;
+		unsigned int action;
+		struct resource r;
+		int j;
+
+		action = entries[i].action;
+		if (action >= MAX_WDAT_ACTIONS) {
+			dev_dbg(&pdev->dev, "Skipping unknown action: %u\n",
+				action);
+			continue;
+		}
+
+		instr = devm_kzalloc(&pdev->dev, sizeof(*instr), GFP_KERNEL);
+		if (!instr)
+			return -ENOMEM;
+
+		INIT_LIST_HEAD(&instr->node);
+		instr->entry = entries[i];
+
+		gas = &entries[i].register_region;
+
+		memset(&r, 0, sizeof(r));
+		r.start = gas->address;
+		r.end = r.start + gas->access_width;
+		if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
+			r.flags = IORESOURCE_MEM;
+		} else if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
+			r.flags = IORESOURCE_IO;
+		} else {
+			dev_dbg(&pdev->dev, "Unsupported address space: %d\n",
+				gas->space_id);
+			continue;
+		}
+
+		/* Find the matching resource */
+		for (j = 0; j < pdev->num_resources; j++) {
+			res = &pdev->resource[j];
+			if (resource_contains(res, &r)) {
+				instr->reg = regs[j] + r.start - res->start;
+				break;
+			}
+		}
+
+		if (!instr->reg) {
+			dev_err(&pdev->dev, "I/O resource not found\n");
+			return -EINVAL;
+		}
+
+		instructions = wdat->instructions[action];
+		if (!instructions) {
+			instructions = devm_kzalloc(&pdev->dev,
+					sizeof(*instructions), GFP_KERNEL);
+			if (!instructions)
+				return -ENOMEM;
+
+			INIT_LIST_HEAD(instructions);
+			wdat->instructions[action] = instructions;
+		}
+
+		list_add_tail(&instr->node, instructions);
+	}
+
+	wdat_wdt_boot_status(wdat);
+	wdat_wdt_set_running(wdat);
+
+	ret = wdat_wdt_enable_reboot(wdat);
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(pdev, wdat);
+
+	watchdog_set_nowayout(&wdat->wdd, nowayout);
+	return devm_watchdog_register_device(&pdev->dev, &wdat->wdd);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int wdat_wdt_suspend_noirq(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct wdat_wdt *wdat = platform_get_drvdata(pdev);
+	int ret;
+
+	if (!watchdog_active(&wdat->wdd))
+		return 0;
+
+	/*
+	 * We need to stop the watchdog if firmare is not doing it or if we
+	 * are going suspend to idle (where firmware is not involved). If
+	 * firmware is stopping the watchdog we kick it here one more time
+	 * to give it some time.
+	 */
+	wdat->stopped = false;
+	if (acpi_target_system_state() == ACPI_STATE_S0 ||
+	    !wdat->stopped_in_sleep) {
+		ret = wdat_wdt_stop(&wdat->wdd);
+		if (!ret)
+			wdat->stopped = true;
+	} else {
+		ret = wdat_wdt_ping(&wdat->wdd);
+	}
+
+	return ret;
+}
+
+static int wdat_wdt_resume_noirq(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct wdat_wdt *wdat = platform_get_drvdata(pdev);
+	int ret;
+
+	if (!watchdog_active(&wdat->wdd))
+		return 0;
+
+	if (!wdat->stopped) {
+		/*
+		 * Looks like the boot firmware reinitializes the watchdog
+		 * before it hands off to the OS on resume from sleep so we
+		 * stop and reprogram the watchdog here.
+		 */
+		ret = wdat_wdt_stop(&wdat->wdd);
+		if (ret)
+			return ret;
+
+		ret = wdat_wdt_set_timeout(&wdat->wdd, wdat->wdd.timeout);
+		if (ret)
+			return ret;
+
+		ret = wdat_wdt_enable_reboot(wdat);
+		if (ret)
+			return ret;
+	}
+
+	return wdat_wdt_start(&wdat->wdd);
+}
+#endif
+
+static const struct dev_pm_ops wdat_wdt_pm_ops = {
+	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(wdat_wdt_suspend_noirq,
+				      wdat_wdt_resume_noirq)
+};
+
+static struct platform_driver wdat_wdt_driver = {
+	.probe = wdat_wdt_probe,
+	.driver = {
+		.name = "wdat_wdt",
+		.pm = &wdat_wdt_pm_ops,
+	},
+};
+
+module_platform_driver(wdat_wdt_driver);
+
+MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>");
+MODULE_DESCRIPTION("ACPI Hardware Watchdog (WDAT) driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:wdat_wdt");