diff options
Diffstat (limited to 'drivers/watchdog/aspeed_wdt.c')
| -rw-r--r-- | drivers/watchdog/aspeed_wdt.c | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c new file mode 100644 index 000000000000..f5ad8023c2e6 --- /dev/null +++ b/drivers/watchdog/aspeed_wdt.c @@ -0,0 +1,212 @@ +/* + * 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"); |