[PATCH 1/6] Driver for the watchdog timer on Freescale IMX2 (and later) processors.
Wolfram Sang
w.sang at pengutronix.de
Thu Apr 29 04:03:17 EDT 2010
Signed-off-by: Wolfram Sang <w.sang at pengutronix.de>
Cc: Vladimir Zapolskiy <vzapolskiy at gmail.com>
Cc: Sascha Hauer <s.hauer at pengutronix.de>
Cc: Wim Van Sebroeck <wim at iguana.be>
---
drivers/watchdog/Kconfig | 12 ++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/imx2_wdt.c | 279 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 292 insertions(+), 0 deletions(-)
create mode 100644 drivers/watchdog/imx2_wdt.c
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 0e8468f..b24baec 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -306,6 +306,18 @@ config MAX63XX_WATCHDOG
help
Support for memory mapped max63{69,70,71,72,73,74} watchdog timer.
+config IMX2_WDT
+ tristate "IMX2+ Watchdog"
+ depends on ARCH_MX2 || ARCH_MX25 || ARCH_MX3 || ARCH_MX5
+ help
+ This is the driver for the hardware watchdog
+ on the Freescale IMX2 and later processors.
+ If you have one of these processors and wish to have
+ watchdog support enabled, say Y, otherwise say N.
+
+ To compile this driver as a module, choose M here: the
+ module will be called imx2_wdt.
+
# AVR32 Architecture
config AT32AP700X_WDT
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 5e3cb95..72f3e20 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -47,6 +47,7 @@ obj-$(CONFIG_STMP3XXX_WATCHDOG) += stmp3xxx_wdt.o
obj-$(CONFIG_NUC900_WATCHDOG) += nuc900_wdt.o
obj-$(CONFIG_ADX_WATCHDOG) += adx_wdt.o
obj-$(CONFIG_TS72XX_WATCHDOG) += ts72xx_wdt.o
+obj-$(CONFIG_IMX2_WDT) += imx2_wdt.o
# AVR32 Architecture
obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c
new file mode 100644
index 0000000..980aa2e
--- /dev/null
+++ b/drivers/watchdog/imx2_wdt.c
@@ -0,0 +1,279 @@
+/*
+ * Watchdog driver for IMX2 and later processors
+ *
+ * Copyright (C) 2010 Wolfram Sang, Pengutronix e.K. <w.sang at pengutronix.de>
+ *
+ * some parts adapted by similar drivers from Darius Augulis and Vladimir
+ * Zapolskiy.
+ *
+ * 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.
+ *
+ * NOTE: MX1 has a slightly different Watchdog than MX2 and later:
+ *
+ * MX1: MX2+:
+ * ---- -----
+ * Registers: 32-bit 16-bit
+ * Stopable timer: Yes No
+ * Need to enable clk: No Yes
+ * Halt on suspend: Manual Can be automatic
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+#include <linux/clk.h>
+#include <linux/fs.h>
+#include <linux/io.h>
+#include <linux/uaccess.h>
+#include <linux/timer.h>
+#include <linux/jiffies.h>
+#include <mach/hardware.h>
+
+#define DRIVER_NAME "imx2-wdt"
+
+#define IMX2_WDT_WCR 0x00 /* Control reg */
+#define IMX2_WDT_WCR_WDZST (1 << 0)
+#define IMX2_WDT_WCR_WDE (1 << 2)
+#define IMX2_WDT_WSR 0x02 /* Service reg */
+
+#define IMX2_WDT_MAX_TIME 128
+#define IMX2_WDT_DEFAULT_TIME 60 /* in seconds */
+#define IMX2_WDT_SEQ1 0x5555
+#define IMX2_WDT_SEQ2 0xAAAA
+
+#define IMX2_WDT_STATUS_OPEN 0
+#define IMX2_WDT_STATUS_STARTED 1
+
+static struct {
+ struct clk *clk;
+ void __iomem *base;
+ unsigned timeout;
+ unsigned long status;
+ struct timer_list timer; /* Pings the watchdog when closed */
+} imx2_wdt;
+
+static struct miscdevice imx2_wdt_miscdev;
+
+static int nowayout = WATCHDOG_NOWAYOUT;
+
+static unsigned timeout = IMX2_WDT_DEFAULT_TIME;
+module_param(timeout, uint, 0);
+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
+
+static const struct watchdog_info imx2_wdt_info = {
+ .identity = "imx2+ watchdog",
+ .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
+};
+
+static void imx2_wdt_ping(void)
+{
+ __raw_writew(IMX2_WDT_SEQ1, imx2_wdt.base + IMX2_WDT_WSR);
+ __raw_writew(IMX2_WDT_SEQ2, imx2_wdt.base + IMX2_WDT_WSR);
+}
+
+static void imx2_wdt_timer_ping(unsigned long arg)
+{
+ imx2_wdt_ping();
+ mod_timer(&imx2_wdt.timer, jiffies + imx2_wdt.timeout * HZ / 2);
+}
+
+static void imx2_wdt_setup(void)
+{
+ u16 val = __raw_readw(imx2_wdt.base + IMX2_WDT_WCR);
+
+ val = (val & 0x00ff) | ((imx2_wdt.timeout * 2 - 1) << 8);
+ val |= IMX2_WDT_WCR_WDE;
+ __raw_writew(val, imx2_wdt.base + IMX2_WDT_WCR);
+ imx2_wdt_ping();
+}
+
+static int imx2_wdt_open(struct inode *inode, struct file *file)
+{
+ if (test_and_set_bit(IMX2_WDT_STATUS_OPEN, &imx2_wdt.status))
+ return -EBUSY;
+
+ clk_enable(imx2_wdt.clk);
+ imx2_wdt_setup();
+ del_timer_sync(&imx2_wdt.timer);
+ set_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status);
+ return nonseekable_open(inode, file);
+}
+
+static int imx2_wdt_close(struct inode *inode, struct file *file)
+{
+ /* no clk_disable. it cannot be disabled once started */
+ clear_bit(IMX2_WDT_STATUS_OPEN, &imx2_wdt.status);
+ if (nowayout)
+ dev_crit(imx2_wdt_miscdev.parent,
+ "Device closed: Expect reboot!\n");
+ else
+ imx2_wdt_timer_ping(0);
+
+ return 0;
+}
+
+static int imx2_wdt_ioctl(struct inode *inode, struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ void __user *argp = (void __user *)arg;
+ int __user *p = argp;
+ int new_value;
+
+ switch (cmd) {
+ case WDIOC_KEEPALIVE:
+ imx2_wdt_ping();
+ return 0;
+
+ case WDIOC_GETSUPPORT:
+ return copy_to_user(argp, &imx2_wdt_info,
+ sizeof(struct watchdog_info)) ? -EFAULT : 0;
+
+ case WDIOC_SETTIMEOUT:
+ if (get_user(new_value, p))
+ return -EFAULT;
+ if ((new_value < 1) || (new_value > IMX2_WDT_MAX_TIME))
+ return -EINVAL;
+
+ imx2_wdt.timeout = new_value;
+ imx2_wdt_setup();
+
+ /* Fallthrough to return current value */
+ case WDIOC_GETTIMEOUT:
+ return put_user(imx2_wdt.timeout, p);
+
+ default:
+ return -ENOTTY;
+ }
+}
+
+static ssize_t imx2_wdt_write(struct file *file, const char *data,
+ size_t len, loff_t *ppos)
+{
+ if (len)
+ imx2_wdt_ping();
+ return len;
+}
+
+static const struct file_operations imx2_wdt_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .ioctl = imx2_wdt_ioctl,
+ .open = imx2_wdt_open,
+ .release = imx2_wdt_close,
+ .write = imx2_wdt_write,
+};
+
+static struct miscdevice imx2_wdt_miscdev = {
+ .minor = WATCHDOG_MINOR,
+ .name = "watchdog",
+ .fops = &imx2_wdt_fops,
+};
+
+static void imx2_wdt_shutdown(struct platform_device *pdev)
+{
+ del_timer_sync(&imx2_wdt.timer);
+ if (test_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status))
+ dev_crit(imx2_wdt_miscdev.parent,
+ "Device shutdown: Expect reboot!\n");
+}
+
+static int __devinit imx2_wdt_probe(struct platform_device *pdev)
+{
+ int ret;
+ int res_size;
+ struct resource *res;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(&pdev->dev, "can't get device resources\n");
+ return -ENODEV;
+ }
+
+ res_size = resource_size(res);
+ if (!devm_request_mem_region(&pdev->dev, res->start, res_size,
+ res->name)) {
+ dev_err(&pdev->dev, "can't allocate %d bytes at %d address\n",
+ res_size, res->start);
+ return -ENOMEM;
+ }
+
+ imx2_wdt.base = devm_ioremap_nocache(&pdev->dev, res->start, res_size);
+ if (!imx2_wdt.base) {
+ dev_err(&pdev->dev, "ioremap failed\n");
+ return -ENOMEM;
+ }
+
+ imx2_wdt.clk = clk_get_sys("imx-wdt.0", NULL);
+ if (IS_ERR(imx2_wdt.clk)) {
+ dev_err(&pdev->dev, "can't get Watchdog clock\n");
+ return PTR_ERR(imx2_wdt.clk);
+ }
+
+ imx2_wdt.timeout = clamp_t(unsigned, timeout, 1, IMX2_WDT_MAX_TIME);
+ if (imx2_wdt.timeout != timeout)
+ dev_warn(&pdev->dev, "Initial timeout out of range! "
+ "Clamped from %u to %u\n", timeout, imx2_wdt.timeout);
+
+ imx2_wdt_miscdev.parent = &pdev->dev;
+ ret = misc_register(&imx2_wdt_miscdev);
+ if (ret)
+ goto fail;
+
+ setup_timer(&imx2_wdt.timer, imx2_wdt_timer_ping, 0);
+ dev_info(&pdev->dev, "IMX2+ Watchdog Timer enabled\n");
+ return 0;
+
+fail:
+ imx2_wdt_miscdev.parent = NULL;
+ clk_put(imx2_wdt.clk);
+ return ret;
+}
+
+static int __devexit imx2_wdt_remove(struct platform_device *pdev)
+{
+ del_timer_sync(&imx2_wdt.timer);
+ misc_deregister(&imx2_wdt_miscdev);
+ imx2_wdt_miscdev.parent = NULL;
+
+ if (test_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status))
+ dev_crit(imx2_wdt_miscdev.parent,
+ "Device removed: Expect reboot!\n");
+ else
+ clk_put(imx2_wdt.clk);
+
+ return 0;
+}
+
+static struct platform_driver imx2_wdt_driver = {
+ .probe = imx2_wdt_probe,
+ .remove = __devexit_p(imx2_wdt_remove),
+ .shutdown = imx2_wdt_shutdown,
+ .driver = {
+ .name = DRIVER_NAME,
+ .owner = THIS_MODULE,
+ },
+};
+
+static int __init imx2_wdt_init(void)
+{
+ return platform_driver_probe(&imx2_wdt_driver, imx2_wdt_probe);
+}
+module_init(imx2_wdt_init);
+
+static void __exit imx2_wdt_exit(void)
+{
+ platform_driver_unregister(&imx2_wdt_driver);
+}
+module_exit(imx2_wdt_exit);
+
+MODULE_AUTHOR("Wolfram Sang");
+MODULE_DESCRIPTION("Watchdog driver for IMX2 and later");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+MODULE_ALIAS("platform:" DRIVER_NAME);
--
1.7.0
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