--- /dev/null
+/*
+ * Copyright 2016 IBM Corporation
+ *
+ * Joel Stanley <joel@jms.id.au>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+
+struct aspeed_wdt {
+ struct watchdog_device wdd;
+ void __iomem *base;
+ u32 ctrl;
+};
+
+static const struct of_device_id aspeed_wdt_of_table[] = {
+ { .compatible = "aspeed,ast2400-wdt" },
+ { .compatible = "aspeed,ast2500-wdt" },
+ { },
+};
+MODULE_DEVICE_TABLE(of, aspeed_wdt_of_table);
+
+#define WDT_STATUS 0x00
+#define WDT_RELOAD_VALUE 0x04
+#define WDT_RESTART 0x08
+#define WDT_CTRL 0x0C
+#define WDT_CTRL_RESET_MODE_SOC (0x00 << 5)
+#define WDT_CTRL_RESET_MODE_FULL_CHIP (0x01 << 5)
+#define WDT_CTRL_1MHZ_CLK BIT(4)
+#define WDT_CTRL_WDT_EXT BIT(3)
+#define WDT_CTRL_WDT_INTR BIT(2)
+#define WDT_CTRL_RESET_SYSTEM BIT(1)
+#define WDT_CTRL_ENABLE BIT(0)
+
+#define WDT_RESTART_MAGIC 0x4755
+
+/* 32 bits at 1MHz, in milliseconds */
+#define WDT_MAX_TIMEOUT_MS 4294967
+#define WDT_DEFAULT_TIMEOUT 30
+#define WDT_RATE_1MHZ 1000000
+
+static struct aspeed_wdt *to_aspeed_wdt(struct watchdog_device *wdd)
+{
+ return container_of(wdd, struct aspeed_wdt, wdd);
+}
+
+static void aspeed_wdt_enable(struct aspeed_wdt *wdt, int count)
+{
+ wdt->ctrl |= WDT_CTRL_ENABLE;
+
+ writel(0, wdt->base + WDT_CTRL);
+ writel(count, wdt->base + WDT_RELOAD_VALUE);
+ writel(WDT_RESTART_MAGIC, wdt->base + WDT_RESTART);
+ writel(wdt->ctrl, wdt->base + WDT_CTRL);
+}
+
+static int aspeed_wdt_start(struct watchdog_device *wdd)
+{
+ struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);
+
+ aspeed_wdt_enable(wdt, wdd->timeout * WDT_RATE_1MHZ);
+
+ return 0;
+}
+
+static int aspeed_wdt_stop(struct watchdog_device *wdd)
+{
+ struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);
+
+ wdt->ctrl &= ~WDT_CTRL_ENABLE;
+ writel(wdt->ctrl, wdt->base + WDT_CTRL);
+
+ return 0;
+}
+
+static int aspeed_wdt_ping(struct watchdog_device *wdd)
+{
+ struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);
+
+ writel(WDT_RESTART_MAGIC, wdt->base + WDT_RESTART);
+
+ return 0;
+}
+
+static int aspeed_wdt_set_timeout(struct watchdog_device *wdd,
+ unsigned int timeout)
+{
+ struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);
+ u32 actual;
+
+ wdd->timeout = timeout;
+
+ actual = min(timeout, wdd->max_hw_heartbeat_ms * 1000);
+
+ writel(actual * WDT_RATE_1MHZ, wdt->base + WDT_RELOAD_VALUE);
+ writel(WDT_RESTART_MAGIC, wdt->base + WDT_RESTART);
+
+ return 0;
+}
+
+static int aspeed_wdt_restart(struct watchdog_device *wdd,
+ unsigned long action, void *data)
+{
+ struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);
+
+ aspeed_wdt_enable(wdt, 128 * WDT_RATE_1MHZ / 1000);
+
+ mdelay(1000);
+
+ return 0;
+}
+
+static const struct watchdog_ops aspeed_wdt_ops = {
+ .start = aspeed_wdt_start,
+ .stop = aspeed_wdt_stop,
+ .ping = aspeed_wdt_ping,
+ .set_timeout = aspeed_wdt_set_timeout,
+ .restart = aspeed_wdt_restart,
+ .owner = THIS_MODULE,
+};
+
+static const struct watchdog_info aspeed_wdt_info = {
+ .options = WDIOF_KEEPALIVEPING
+ | WDIOF_MAGICCLOSE
+ | WDIOF_SETTIMEOUT,
+ .identity = KBUILD_MODNAME,
+};
+
+static int aspeed_wdt_remove(struct platform_device *pdev)
+{
+ struct aspeed_wdt *wdt = platform_get_drvdata(pdev);
+
+ watchdog_unregister_device(&wdt->wdd);
+
+ return 0;
+}
+
+static int aspeed_wdt_probe(struct platform_device *pdev)
+{
+ struct aspeed_wdt *wdt;
+ struct resource *res;
+ int ret;
+
+ wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
+ if (!wdt)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ wdt->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(wdt->base))
+ return PTR_ERR(wdt->base);
+
+ /*
+ * The ast2400 wdt can run at PCLK, or 1MHz. The ast2500 only
+ * runs at 1MHz. We chose to always run at 1MHz, as there's no
+ * good reason to have a faster watchdog counter.
+ */
+ wdt->wdd.info = &aspeed_wdt_info;
+ wdt->wdd.ops = &aspeed_wdt_ops;
+ wdt->wdd.max_hw_heartbeat_ms = WDT_MAX_TIMEOUT_MS;
+ wdt->wdd.parent = &pdev->dev;
+
+ wdt->wdd.timeout = WDT_DEFAULT_TIMEOUT;
+ watchdog_init_timeout(&wdt->wdd, 0, &pdev->dev);
+
+ /*
+ * Control reset on a per-device basis to ensure the
+ * host is not affected by a BMC reboot, so only reset
+ * the SOC and not the full chip
+ */
+ wdt->ctrl = WDT_CTRL_RESET_MODE_SOC |
+ WDT_CTRL_1MHZ_CLK |
+ WDT_CTRL_RESET_SYSTEM;
+
+ if (readl(wdt->base + WDT_CTRL) & WDT_CTRL_ENABLE) {
+ aspeed_wdt_start(&wdt->wdd);
+ set_bit(WDOG_HW_RUNNING, &wdt->wdd.status);
+ }
+
+ ret = watchdog_register_device(&wdt->wdd);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to register\n");
+ return ret;
+ }
+
+ platform_set_drvdata(pdev, wdt);
+
+ return 0;
+}
+
+static struct platform_driver aspeed_watchdog_driver = {
+ .probe = aspeed_wdt_probe,
+ .remove = aspeed_wdt_remove,
+ .driver = {
+ .name = KBUILD_MODNAME,
+ .of_match_table = of_match_ptr(aspeed_wdt_of_table),
+ },
+};
+module_platform_driver(aspeed_watchdog_driver);
+
+MODULE_DESCRIPTION("Aspeed Watchdog Driver");
+MODULE_LICENSE("GPL");
projects / linux.git / commitdiff