watchdog: Add Aspeed ast2400 watchdog driver

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>

4 files changed, 235 insertions, 10 deletions

diff --git a/arch/arm/mach-aspeed/aspeed.c b/arch/arm/mach-aspeed/aspeed.c
index 397045d490a2..e852489475d3 100644
--- a/arch/arm/mach-aspeed/aspeed.c
+++ b/arch/arm/mach-aspeed/aspeed.c
@@ -204,15 +204,6 @@ static void __init aspeed_init_early(void)
 		do_palmetto_setup();
 }
 
-static void aspeed_restart(enum reboot_mode mode, const char *cmd)
-{
-	// XXX Move that to WDT driver
-	writel(0x0010, AST_IO(AST_BASE_WDT | 0x04));
-	writel(0x0003, AST_IO(AST_BASE_WDT | 0x0c));
-	writel(0x4755, AST_IO(AST_BASE_WDT | 0x08));
-	for (;;);
-}
-
 static void __init aspeed_map_io(void)
 {
 	iotable_init(aspeed_io_desc, ARRAY_SIZE(aspeed_io_desc));
@@ -231,5 +222,4 @@ DT_MACHINE_START(aspeed_dt, "ASpeed SoC")
 	.init_early	= aspeed_init_early,
 	.init_machine	= aspeed_dt_init,
 	.dt_compat	= aspeed_dt_match,
-	.restart	= aspeed_restart,
 MACHINE_END
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 1c427beffadd..48dddc7159e2 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -578,6 +578,16 @@ config LPC18XX_WATCHDOG
 	  To compile this driver as a module, choose M here: the
 	  module will be called lpc18xx_wdt.
 
+config ASPEED_24xx_WATCHDOG
+	tristate "Aspeed 23xx 24xx SoCs watchdog support"
+	depends on (ARCH_ASPEED || COMPILE_TEST) && OF
+	select WATCHDOG_CORE
+	help
+	  Say Y here to include support for the watchdog timer
+	  in Apseed 23xx or 24xx BMC SoCs.
+	  To compile this driver as a module, choose M here: the
+	  module will be called aspeed_wdt.
+
 # AVR32 Architecture
 
 config AT32AP700X_WDT
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 53d4827ddfe1..f4c9e4f1d85c 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -69,6 +69,7 @@ obj-$(CONFIG_MEDIATEK_WATCHDOG) += mtk_wdt.o
 obj-$(CONFIG_DIGICOLOR_WATCHDOG) += digicolor_wdt.o
 obj-$(CONFIG_LPC18XX_WATCHDOG) += lpc18xx_wdt.o
 obj-$(CONFIG_BCM7038_WDT) += bcm7038_wdt.o
+obj-$(CONFIG_ASPEED_24xx_WATCHDOG) += aspeed_wdt.o
 
 # AVR32 Architecture
 obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c
new file mode 100644
index 000000000000..a1ea4c286e6c
--- /dev/null
+++ b/drivers/watchdog/aspeed_wdt.c
@@ -0,0 +1,224 @@
+/*
+ * Copyright 2015 IBM Corp.
+ *
+ * Joel Stanley <joel@jms.id.au>
+ *
+ * Based on the qcom-watchdog driver
+ *
+ * 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/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/reboot.h>
+#include <linux/watchdog.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+
+struct aspeed_wdt {
+	struct watchdog_device	wdd;
+	struct clk		*clk;
+	unsigned long		rate;
+	struct notifier_block	restart_nb;
+	void __iomem		*base;
+};
+
+static const struct of_device_id aspeed_wdt_of_table[] = {
+	{ .compatible = "aspeed,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_RESET_SYSTEM		(0x1  << 1)
+#define   WDT_CTRL_ENABLE		(0x1  << 0)
+
+#define	WDT_RESTART_MAGIC	0x4755
+
+static void aspeed_wdt_enable(struct aspeed_wdt *wdt, int count)
+{
+	u32 ctrl = WDT_CTRL_RESET_MODE_SOC | WDT_CTRL_RESET_SYSTEM |
+		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(ctrl, wdt->base + WDT_CTRL);
+}
+
+static int aspeed_wdt_start(struct watchdog_device *wdd)
+{
+	struct aspeed_wdt *wdt = container_of(wdd, struct aspeed_wdt, wdd);
+	dev_dbg(wdd->dev, "starting with timeout of %d (rate %lu)\n",
+			  wdd->timeout, wdt->rate);
+	aspeed_wdt_enable(wdt, wdd->timeout * wdt->rate);
+	return 0;
+}
+
+static int aspeed_wdt_stop(struct watchdog_device *wdd)
+{
+	struct aspeed_wdt *wdt = container_of(wdd, struct aspeed_wdt, wdd);
+
+	writel(0, wdt->base + WDT_CTRL);
+	return 0;
+}
+
+static int aspeed_wdt_ping(struct watchdog_device *wdd)
+{
+	struct aspeed_wdt *wdt = container_of(wdd, struct aspeed_wdt, wdd);
+
+	dev_dbg(wdd->dev, "ping\n");
+	writel(WDT_RESTART_MAGIC, wdt->base + WDT_RESTART);
+	return 0;
+}
+
+static int aspeed_wdt_set_timeout(struct watchdog_device *wdd,
+				  unsigned int timeout)
+{
+	dev_dbg(wdd->dev, "timeout set to %u\n", timeout);
+	wdd->timeout = timeout;
+	return aspeed_wdt_start(wdd);
+}
+
+static int aspeed_wdt_restart(struct notifier_block *nb, unsigned long action,
+			      void *data)
+{
+	struct aspeed_wdt *wdt = container_of(nb,
+			struct aspeed_wdt, restart_nb);
+
+	/*
+	 * Trigger watchdog bite:
+	 *    Setup reload count to be 128ms, and enable WDT.
+	 */
+	aspeed_wdt_enable(wdt, 128 * wdt->rate / 1000);
+
+	return NOTIFY_DONE;
+}
+
+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,
+	.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);
+
+	unregister_restart_handler(&wdt->restart_nb);
+	watchdog_unregister_device(&wdt->wdd);
+	clk_disable_unprepare(wdt->clk);
+	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);
+
+	wdt->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(wdt->clk)) {
+		dev_err(&pdev->dev, "failed to get input clock\n");
+		return PTR_ERR(wdt->clk);
+	}
+
+	ret = clk_prepare_enable(wdt->clk);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to setup clock\n");
+		goto err;
+	}
+
+	/*
+	 * We use the clock rate to calculate the max timeout, so ensure it's
+	 * not zero to avoid a divide-by-zero exception.
+	 *
+	 * WATCHDOG_CORE assumes units of seconds, if the WDT is clocked such
+	 * that it would bite before a second elapses it's usefulness is
+	 * limited.  Bail if this is the case.
+	 */
+	wdt->rate = clk_get_rate(wdt->clk);
+	if (wdt->rate == 0 ||
+	    wdt->rate > 0x10000000U) {
+		dev_err(&pdev->dev, "invalid clock rate\n");
+		ret = -EINVAL;
+		goto err;
+	}
+
+	wdt->wdd.dev = &pdev->dev;
+	wdt->wdd.info = &aspeed_wdt_info;
+	wdt->wdd.ops = &aspeed_wdt_ops;
+	wdt->wdd.min_timeout = 1;
+	wdt->wdd.max_timeout = 0x10000000U / wdt->rate;
+
+	/*
+	 * If 'timeout-sec' unspecified in devicetree, assume a 30 second
+	 * default, unless the max timeout is less than 30 seconds, then use
+	 * the max instead.
+	 */
+	wdt->wdd.timeout = min(wdt->wdd.max_timeout, 30U);
+	watchdog_init_timeout(&wdt->wdd, 0, &pdev->dev);
+
+	ret = watchdog_register_device(&wdt->wdd);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to register\n");
+		goto err;
+	}
+
+	/*
+	 * WDT restart notifier has priority 0 (use as a last resort)
+	 */
+	wdt->restart_nb.notifier_call = aspeed_wdt_restart;
+	ret = register_restart_handler(&wdt->restart_nb);
+	if (ret)
+		dev_err(&pdev->dev, "failed to setup restart handler\n");
+
+	dev_info(&pdev->dev, "rate %lu, max timeout %u, timeout %d\n",
+		 wdt->rate, wdt->wdd.max_timeout, wdt->wdd.timeout);
+
+	platform_set_drvdata(pdev, wdt);
+	return 0;
+
+err:
+	clk_disable_unprepare(wdt->clk);
+	return ret;
+}
+
+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 AST23/4xx Watchdog Driver");