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path: root/drivers/watchdog/mt7621_wdt.c
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Diffstat (limited to 'drivers/watchdog/mt7621_wdt.c')
-rw-r--r--drivers/watchdog/mt7621_wdt.c189
1 files changed, 189 insertions, 0 deletions
diff --git a/drivers/watchdog/mt7621_wdt.c b/drivers/watchdog/mt7621_wdt.c
new file mode 100644
index 000000000..a8aa3522c
--- /dev/null
+++ b/drivers/watchdog/mt7621_wdt.c
@@ -0,0 +1,189 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Ralink MT7621/MT7628 built-in hardware watchdog timer
+ *
+ * Copyright (C) 2014 John Crispin <john@phrozen.org>
+ *
+ * This driver was based on: drivers/watchdog/rt2880_wdt.c
+ */
+
+#include <linux/clk.h>
+#include <linux/reset.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/watchdog.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/mod_devicetable.h>
+
+#include <asm/mach-ralink/ralink_regs.h>
+
+#define SYSC_RSTSTAT 0x38
+#define WDT_RST_CAUSE BIT(1)
+
+#define RALINK_WDT_TIMEOUT 30
+
+#define TIMER_REG_TMRSTAT 0x00
+#define TIMER_REG_TMR1LOAD 0x24
+#define TIMER_REG_TMR1CTL 0x20
+
+#define TMR1CTL_ENABLE BIT(7)
+#define TMR1CTL_RESTART BIT(9)
+#define TMR1CTL_PRESCALE_SHIFT 16
+
+static void __iomem *mt7621_wdt_base;
+static struct reset_control *mt7621_wdt_reset;
+
+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 inline void rt_wdt_w32(unsigned reg, u32 val)
+{
+ iowrite32(val, mt7621_wdt_base + reg);
+}
+
+static inline u32 rt_wdt_r32(unsigned reg)
+{
+ return ioread32(mt7621_wdt_base + reg);
+}
+
+static int mt7621_wdt_ping(struct watchdog_device *w)
+{
+ rt_wdt_w32(TIMER_REG_TMRSTAT, TMR1CTL_RESTART);
+
+ return 0;
+}
+
+static int mt7621_wdt_set_timeout(struct watchdog_device *w, unsigned int t)
+{
+ w->timeout = t;
+ rt_wdt_w32(TIMER_REG_TMR1LOAD, t * 1000);
+ mt7621_wdt_ping(w);
+
+ return 0;
+}
+
+static int mt7621_wdt_start(struct watchdog_device *w)
+{
+ u32 t;
+
+ /* set the prescaler to 1ms == 1000us */
+ rt_wdt_w32(TIMER_REG_TMR1CTL, 1000 << TMR1CTL_PRESCALE_SHIFT);
+
+ mt7621_wdt_set_timeout(w, w->timeout);
+
+ t = rt_wdt_r32(TIMER_REG_TMR1CTL);
+ t |= TMR1CTL_ENABLE;
+ rt_wdt_w32(TIMER_REG_TMR1CTL, t);
+
+ return 0;
+}
+
+static int mt7621_wdt_stop(struct watchdog_device *w)
+{
+ u32 t;
+
+ mt7621_wdt_ping(w);
+
+ t = rt_wdt_r32(TIMER_REG_TMR1CTL);
+ t &= ~TMR1CTL_ENABLE;
+ rt_wdt_w32(TIMER_REG_TMR1CTL, t);
+
+ return 0;
+}
+
+static int mt7621_wdt_bootcause(void)
+{
+ if (rt_sysc_r32(SYSC_RSTSTAT) & WDT_RST_CAUSE)
+ return WDIOF_CARDRESET;
+
+ return 0;
+}
+
+static int mt7621_wdt_is_running(struct watchdog_device *w)
+{
+ return !!(rt_wdt_r32(TIMER_REG_TMR1CTL) & TMR1CTL_ENABLE);
+}
+
+static const struct watchdog_info mt7621_wdt_info = {
+ .identity = "Mediatek Watchdog",
+ .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+};
+
+static const struct watchdog_ops mt7621_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = mt7621_wdt_start,
+ .stop = mt7621_wdt_stop,
+ .ping = mt7621_wdt_ping,
+ .set_timeout = mt7621_wdt_set_timeout,
+};
+
+static struct watchdog_device mt7621_wdt_dev = {
+ .info = &mt7621_wdt_info,
+ .ops = &mt7621_wdt_ops,
+ .min_timeout = 1,
+ .max_timeout = 0xfffful / 1000,
+};
+
+static int mt7621_wdt_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ mt7621_wdt_base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(mt7621_wdt_base))
+ return PTR_ERR(mt7621_wdt_base);
+
+ mt7621_wdt_reset = devm_reset_control_get_exclusive(dev, NULL);
+ if (!IS_ERR(mt7621_wdt_reset))
+ reset_control_deassert(mt7621_wdt_reset);
+
+ mt7621_wdt_dev.bootstatus = mt7621_wdt_bootcause();
+
+ watchdog_init_timeout(&mt7621_wdt_dev, mt7621_wdt_dev.max_timeout,
+ dev);
+ watchdog_set_nowayout(&mt7621_wdt_dev, nowayout);
+ if (mt7621_wdt_is_running(&mt7621_wdt_dev)) {
+ /*
+ * Make sure to apply timeout from watchdog core, taking
+ * the prescaler of this driver here into account (the
+ * boot loader might be using a different prescaler).
+ *
+ * To avoid spurious resets because of different scaling,
+ * we first disable the watchdog, set the new prescaler
+ * and timeout, and then re-enable the watchdog.
+ */
+ mt7621_wdt_stop(&mt7621_wdt_dev);
+ mt7621_wdt_start(&mt7621_wdt_dev);
+ set_bit(WDOG_HW_RUNNING, &mt7621_wdt_dev.status);
+ }
+
+ return devm_watchdog_register_device(dev, &mt7621_wdt_dev);
+}
+
+static void mt7621_wdt_shutdown(struct platform_device *pdev)
+{
+ mt7621_wdt_stop(&mt7621_wdt_dev);
+}
+
+static const struct of_device_id mt7621_wdt_match[] = {
+ { .compatible = "mediatek,mt7621-wdt" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, mt7621_wdt_match);
+
+static struct platform_driver mt7621_wdt_driver = {
+ .probe = mt7621_wdt_probe,
+ .shutdown = mt7621_wdt_shutdown,
+ .driver = {
+ .name = KBUILD_MODNAME,
+ .of_match_table = mt7621_wdt_match,
+ },
+};
+
+module_platform_driver(mt7621_wdt_driver);
+
+MODULE_DESCRIPTION("MediaTek MT762x hardware watchdog driver");
+MODULE_AUTHOR("John Crispin <john@phrozen.org");
+MODULE_LICENSE("GPL v2");