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path: root/drivers/watchdog/wdat_wdt.c
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Diffstat (limited to 'drivers/watchdog/wdat_wdt.c')
-rw-r--r--drivers/watchdog/wdat_wdt.c547
1 files changed, 547 insertions, 0 deletions
diff --git a/drivers/watchdog/wdat_wdt.c b/drivers/watchdog/wdat_wdt.c
new file mode 100644
index 000000000..ce7a4a9e4
--- /dev/null
+++ b/drivers/watchdog/wdat_wdt.c
@@ -0,0 +1,547 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ACPI Hardware Watchdog (WDAT) driver.
+ *
+ * Copyright (C) 2016, Intel Corporation
+ * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
+ */
+
+#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
+ * @instructions: 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) ")");
+
+#define WDAT_DEFAULT_TIMEOUT 30
+
+static int timeout = WDAT_DEFAULT_TIMEOUT;
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="
+ __MODULE_STRING(WDAT_DEFAULT_TIMEOUT) ")");
+
+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
+ * recommended to make it configurable through hardware register. We
+ * enable reboot now if it is configurable, 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_CURRENT_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)
+{
+ struct device *dev = &pdev->dev;
+ 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(dev, sizeof(*wdat), GFP_KERNEL);
+ if (!wdat)
+ return -ENOMEM;
+
+ regs = devm_kcalloc(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_timeout = DIV_ROUND_UP(wdat->period * tbl->min_count, 1000);
+ wdat->wdd.max_timeout = wdat->period * tbl->max_count / 1000;
+ 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(dev, res);
+ if (IS_ERR(reg))
+ return PTR_ERR(reg);
+ } else if (resource_type(res) == IORESOURCE_IO) {
+ reg = devm_ioport_map(dev, res->start, 1);
+ if (!reg)
+ return -ENOMEM;
+ } else {
+ dev_err(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(dev, "Skipping unknown action: %u\n", action);
+ continue;
+ }
+
+ instr = devm_kzalloc(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 + ACPI_ACCESS_BYTE_WIDTH(gas->access_width) - 1;
+ 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(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(dev, "I/O resource not found\n");
+ return -EINVAL;
+ }
+
+ instructions = wdat->instructions[action];
+ if (!instructions) {
+ instructions = devm_kzalloc(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);
+
+ /*
+ * Set initial timeout so that userspace has time to configure the
+ * watchdog properly after it has opened the device. In some cases
+ * the BIOS default is too short and causes immediate reboot.
+ */
+ if (watchdog_timeout_invalid(&wdat->wdd, timeout)) {
+ dev_warn(dev, "Invalid timeout %d given, using %d\n",
+ timeout, WDAT_DEFAULT_TIMEOUT);
+ timeout = WDAT_DEFAULT_TIMEOUT;
+ }
+
+ ret = wdat_wdt_set_timeout(&wdat->wdd, timeout);
+ if (ret)
+ return ret;
+
+ watchdog_set_nowayout(&wdat->wdd, nowayout);
+ watchdog_stop_on_reboot(&wdat->wdd);
+ watchdog_stop_on_unregister(&wdat->wdd);
+ return devm_watchdog_register_device(dev, &wdat->wdd);
+}
+
+static int wdat_wdt_suspend_noirq(struct device *dev)
+{
+ struct wdat_wdt *wdat = dev_get_drvdata(dev);
+ int ret;
+
+ if (!watchdog_active(&wdat->wdd))
+ return 0;
+
+ /*
+ * We need to stop the watchdog if firmware 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 wdat_wdt *wdat = dev_get_drvdata(dev);
+ 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;
+
+ ret = wdat_wdt_ping(&wdat->wdd);
+ if (ret)
+ return ret;
+ }
+
+ return wdat_wdt_start(&wdat->wdd);
+}
+
+static const struct dev_pm_ops wdat_wdt_pm_ops = {
+ 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 = pm_sleep_ptr(&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");
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