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[PATCH 2/2] watchdog: MIPS: add ralink watchdog driver

To: Wim Van Sebroeck <wim@iguana.be>
Subject: [PATCH 2/2] watchdog: MIPS: add ralink watchdog driver
From: John Crispin <blogic@openwrt.org>
Date: Thu, 8 Aug 2013 11:31:43 +0200
Cc: John Crispin <blogic@openwrt.org>, linux-watchdog@vger.kernel.org, linux-mips@linux-mips.org
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Sender: linux-mips-bounce@linux-mips.org
Add a driver for the watchdog timer found on Ralink SoC

Signed-off-by: John Crispin <blogic@openwrt.org>
Cc: linux-watchdog@vger.kernel.org
Cc: linux-mips@linux-mips.org
---
 drivers/watchdog/Kconfig      |    7 ++
 drivers/watchdog/Makefile     |    1 +
 drivers/watchdog/rt2880_wdt.c |  208 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 216 insertions(+)
 create mode 100644 drivers/watchdog/rt2880_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 362085d..00b1450 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -1117,6 +1117,13 @@ config LANTIQ_WDT
        help
          Hardware driver for the Lantiq SoC Watchdog Timer.
 
+config RALINK_WDT
+       tristate "Ralink SoC watchdog"
+       select WATCHDOG_CORE
+       depends on RALINK
+       help
+         Hardware driver for the Ralink SoC Watchdog Timer.
+
 # PARISC Architecture
 
 # POWERPC Architecture
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 2f26a0b..8ce381d 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -135,6 +135,7 @@ obj-$(CONFIG_TXX9_WDT) += txx9wdt.o
 obj-$(CONFIG_OCTEON_WDT) += octeon-wdt.o
 octeon-wdt-y := octeon-wdt-main.o octeon-wdt-nmi.o
 obj-$(CONFIG_LANTIQ_WDT) += lantiq_wdt.o
+obj-$(CONFIG_RALINK_WDT) += rt2880_wdt.o
 
 # PARISC Architecture
 
diff --git a/drivers/watchdog/rt2880_wdt.c b/drivers/watchdog/rt2880_wdt.c
new file mode 100644
index 0000000..4d07964
--- /dev/null
+++ b/drivers/watchdog/rt2880_wdt.c
@@ -0,0 +1,208 @@
+/*
+ * Ralink RT288x/RT3xxx/MT76xx built-in hardware watchdog timer
+ *
+ * Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org>
+ * Copyright (C) 2013 John Crispin <blogic@openwrt.org>
+ *
+ * This driver was based on: drivers/watchdog/softdog.c
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#include <linux/clk.h>
+#include <linux/reset.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/watchdog.h>
+#include <linux/miscdevice.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+
+#include <asm/mach-ralink/ralink_regs.h>
+
+#define SYSC_RSTSTAT                   0x38
+#define WDT_RST_CAUSE                  BIT(1)
+
+#define RALINK_WDT_TIMEOUT             30
+#define RALINK_WDT_PRESCALE            65536
+
+#define TIMER_REG_TMR1LOAD             0x00
+#define TIMER_REG_TMR1CTL              0x08
+
+#define TMRSTAT_TMR1RST                        BIT(5)
+
+#define TMR1CTL_ENABLE                 BIT(7)
+#define TMR1CTL_MODE_SHIFT             4
+#define TMR1CTL_MODE_MASK              0x3
+#define TMR1CTL_MODE_FREE_RUNNING      0x0
+#define TMR1CTL_MODE_PERIODIC          0x1
+#define TMR1CTL_MODE_TIMEOUT           0x2
+#define TMR1CTL_MODE_WDT               0x3
+#define TMR1CTL_PRESCALE_MASK          0xf
+#define TMR1CTL_PRESCALE_65536         0xf
+
+static struct clk *rt288x_wdt_clk;
+static unsigned long rt288x_wdt_freq;
+static void __iomem *rt288x_wdt_base;
+
+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, rt288x_wdt_base + reg);
+}
+
+static inline u32 rt_wdt_r32(unsigned reg)
+{
+       return ioread32(rt288x_wdt_base + reg);
+}
+
+static int rt288x_wdt_ping(struct watchdog_device *w)
+{
+       rt_wdt_w32(TIMER_REG_TMR1LOAD, w->timeout * rt288x_wdt_freq);
+
+       return 0;
+}
+
+static int rt288x_wdt_start(struct watchdog_device *w)
+{
+       u32 t;
+
+       t = rt_wdt_r32(TIMER_REG_TMR1CTL);
+       t &= ~(TMR1CTL_MODE_MASK << TMR1CTL_MODE_SHIFT |
+               TMR1CTL_PRESCALE_MASK);
+       t |= (TMR1CTL_MODE_WDT << TMR1CTL_MODE_SHIFT |
+               TMR1CTL_PRESCALE_65536);
+       rt_wdt_w32(TIMER_REG_TMR1CTL, t);
+
+       rt288x_wdt_ping(w);
+
+       t = rt_wdt_r32(TIMER_REG_TMR1CTL);
+       t |= TMR1CTL_ENABLE;
+       rt_wdt_w32(TIMER_REG_TMR1CTL, t);
+
+       return 0;
+}
+
+static int rt288x_wdt_stop(struct watchdog_device *w)
+{
+       u32 t;
+
+       rt288x_wdt_ping(w);
+
+       t = rt_wdt_r32(TIMER_REG_TMR1CTL);
+       t &= ~TMR1CTL_ENABLE;
+       rt_wdt_w32(TIMER_REG_TMR1CTL, t);
+
+       return 0;
+}
+
+static int rt288x_wdt_set_timeout(struct watchdog_device *w, unsigned int t)
+{
+       w->timeout = t;
+       rt288x_wdt_ping(w);
+
+       return 0;
+}
+
+static int rt288x_wdt_bootcause(void)
+{
+       if (rt_sysc_r32(SYSC_RSTSTAT) & WDT_RST_CAUSE)
+               return WDIOF_CARDRESET;
+
+       return 0;
+}
+
+static struct watchdog_info rt288x_wdt_info = {
+       .identity = "Ralink Watchdog",
+       .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+};
+
+static struct watchdog_ops rt288x_wdt_ops = {
+       .owner = THIS_MODULE,
+       .start = rt288x_wdt_start,
+       .stop = rt288x_wdt_stop,
+       .ping = rt288x_wdt_ping,
+       .set_timeout = rt288x_wdt_set_timeout,
+};
+
+static struct watchdog_device rt288x_wdt_dev = {
+       .info = &rt288x_wdt_info,
+       .ops = &rt288x_wdt_ops,
+       .min_timeout = 1,
+};
+
+static int rt288x_wdt_probe(struct platform_device *pdev)
+{
+       struct resource *res;
+       int ret;
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       rt288x_wdt_base = devm_request_and_ioremap(&pdev->dev, res);
+       if (IS_ERR(rt288x_wdt_base))
+               return PTR_ERR(rt288x_wdt_base);
+
+       rt288x_wdt_clk = devm_clk_get(&pdev->dev, NULL);
+       if (IS_ERR(rt288x_wdt_clk))
+               return PTR_ERR(rt288x_wdt_clk);
+
+       device_reset(&pdev->dev);
+
+       rt288x_wdt_freq = clk_get_rate(rt288x_wdt_clk) / RALINK_WDT_PRESCALE;
+
+       rt288x_wdt_dev.dev = &pdev->dev;
+       rt288x_wdt_dev.bootstatus = rt288x_wdt_bootcause();
+
+       rt288x_wdt_dev.max_timeout = (0xfffful / rt288x_wdt_freq);
+       rt288x_wdt_dev.timeout = rt288x_wdt_dev.max_timeout;
+
+       watchdog_set_nowayout(&rt288x_wdt_dev, nowayout);
+
+       ret = watchdog_register_device(&rt288x_wdt_dev);
+       if (!ret)
+               dev_info(&pdev->dev, "Initialized\n");
+
+       return 0;
+}
+
+static int rt288x_wdt_remove(struct platform_device *pdev)
+{
+       watchdog_unregister_device(&rt288x_wdt_dev);
+
+       return 0;
+}
+
+static void rt288x_wdt_shutdown(struct platform_device *pdev)
+{
+       rt288x_wdt_stop(&rt288x_wdt_dev);
+}
+
+static const struct of_device_id rt288x_wdt_match[] = {
+       { .compatible = "ralink,rt2880-wdt" },
+       {},
+};
+MODULE_DEVICE_TABLE(of, rt288x_wdt_match);
+
+static struct platform_driver rt288x_wdt_driver = {
+       .probe          = rt288x_wdt_probe,
+       .remove         = rt288x_wdt_remove,
+       .shutdown       = rt288x_wdt_shutdown,
+       .driver         = {
+               .name           = KBUILD_MODNAME,
+               .owner          = THIS_MODULE,
+               .of_match_table = rt288x_wdt_match,
+       },
+};
+
+module_platform_driver(rt288x_wdt_driver);
+
+MODULE_DESCRIPTION("MediaTek/Ralink RT288x/RT3xxx hardware watchdog driver");
+MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
-- 
1.7.10.4


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