[PATCH] Driver for the watchdog timer on all Freescale IMX processors.
Wolfram Sang
w.sang at pengutronix.de
Tue Dec 8 10:39:12 EST 2009
Signed-off-by: Darius Augulis <augulis.darius at gmail.com>
Signed-off-by: Wolfram Sang <w.sang at pengutronix.de>
Cc: Sascha Hauer <s.hauer at pengutronix.de>
Cc: Wim Van Sebroeck <wim at iguana.be>
---
Changes since the last version from Darius:
* removed all #ifdef CONFIG_ARCH_* and handle the differences at runtime
* simplified house-keeping of the timeout value and fixed the conversion
into the corresponding register value
* removed a superfluous static platform-device
* removed debug output and comments with (IMHO) little information
* cleaned up #includes
* fixed some typos & removed unnecessary tabs & added kernel coding style
* probably something else...
drivers/watchdog/Kconfig | 12 ++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/imx_wdt.c | 342 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 355 insertions(+), 0 deletions(-)
create mode 100644 drivers/watchdog/imx_wdt.c
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 3711b88..964cfc4 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -73,6 +73,18 @@ config WM8350_WATCHDOG
# ARM Architecture
+config IMX_WDT
+ tristate "IMX Watchdog"
+ depends on ARCH_MXC
+ help
+ This is the driver for the hardware watchdog
+ on the Freescale IMX 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 imx_wdt.
+
config AT91RM9200_WATCHDOG
tristate "AT91RM9200 watchdog"
depends on ARCH_AT91RM9200
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 699199b..b77df3f 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -46,6 +46,7 @@ obj-$(CONFIG_COH901327_WATCHDOG) += coh901327_wdt.o
obj-$(CONFIG_STMP3XXX_WATCHDOG) += stmp3xxx_wdt.o
obj-$(CONFIG_NUC900_WATCHDOG) += nuc900_wdt.o
obj-$(CONFIG_ADX_WATCHDOG) += adx_wdt.o
+obj-$(CONFIG_IMX_WDT) += imx_wdt.o
# AVR32 Architecture
obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
diff --git a/drivers/watchdog/imx_wdt.c b/drivers/watchdog/imx_wdt.c
new file mode 100644
index 0000000..759680e
--- /dev/null
+++ b/drivers/watchdog/imx_wdt.c
@@ -0,0 +1,342 @@
+/*
+ * Watchdog driver for IMX processors
+ *
+ * Copyright (C) 2008 Darius Augulis <augulis.darius at gmail.com>
+ * Copyright (C) 2009 Wolfram Sang <w.sang at pengutronix.de>
+ *
+ * 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 MX3. It is not
+ * possible to turn off the watchdog on MX2 or MX3 once it's enabled. Thus,
+ * timeout changing with IOCTL command is possible only on MX1. WD timer
+ * halting during suspend is implemented in all archs but in different ways.
+ *
+ * MX2 and MX3 have 16 bit watchdog registers compared to 32 bit on MX1.
+ * The layout is the same, so the offsets are corrected on the fly.
+ */
+
+#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 <mach/hardware.h>
+
+#define IMX_WDT_WCR 0x00 /* Control reg */
+#define IMX_WDT1_WCR_WDE (1 << 0)
+#define IMX_WDT1_WCR_WDEC (1 << 1)
+#define IMX_WDT1_WCR_WHALT (1 << 15)
+#define IMX_WDT2_WCR_WDZST (1 << 0)
+#define IMX_WDT2_WCR_WDE (1 << 2)
+#define IMX_WDT_WSR 0x02 /* Service reg */
+
+#define IMX_WDT1_MAX_TIME 64
+#define IMX_WDT2_MAX_TIME 128
+#define IMX_WDT_DEFAULT_TIME 10 /* in seconds */
+#define IMX_WDT_SEQ1 0x5555
+#define IMX_WDT_SEQ2 0xAAAA
+
+struct imx_wdt_struct {
+ struct resource *res;
+ struct device *dev;
+ struct clk *clk;
+ void __iomem *base;
+ unsigned timeout;
+ unsigned long status;
+};
+
+static struct imx_wdt_struct imx_wdt;
+
+static unsigned timeout = IMX_WDT_DEFAULT_TIME;
+module_param(timeout, uint, 0);
+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
+
+static struct watchdog_info imx1_wdt_info = {
+ .identity = "imx1 watchdog",
+ .firmware_version = 1,
+ .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
+};
+
+static struct watchdog_info imx2_wdt_info = {
+ .identity = "imx2+ watchdog",
+ .firmware_version = 2,
+ .options = WDIOF_KEEPALIVEPING,
+};
+
+static void imx_wdt_ping(struct imx_wdt_struct *imx_wdt)
+{
+ unsigned offset = IMX_WDT_WSR << (cpu_is_mx1() ? 1 : 0);
+ __raw_writew(IMX_WDT_SEQ1, imx_wdt->base + offset);
+ __raw_writew(IMX_WDT_SEQ2, imx_wdt->base + offset);
+}
+
+static void imx_wdt_stop(struct imx_wdt_struct *imx_wdt)
+{
+ if (cpu_is_mx1())
+ __raw_writew(0, imx_wdt->base + IMX_WDT_WCR);
+ else
+ dev_warn(imx_wdt->dev, "watchdog cannot be stopped!\n");
+}
+
+static void imx_wdt_start(struct imx_wdt_struct *imx_wdt)
+{
+ u16 val = __raw_readw(imx_wdt->base + IMX_WDT_WCR);
+
+ /* clears also IMX_WDT1_WCR_WHALT on IMX1 */
+ val = (val & 0x00ff) | ((imx_wdt->timeout * 2 - 1) << 8);
+ __raw_writew(val, imx_wdt->base + IMX_WDT_WCR);
+
+ if (cpu_is_mx1()) {
+#ifndef CONFIG_WATCHDOG_NOWAYOUT
+ val |= IMX_WDT1_WCR_WDEC;
+#endif
+ val |= IMX_WDT1_WCR_WDE;
+ } else {
+ val |= IMX_WDT2_WCR_WDE | IMX_WDT2_WCR_WDZST;
+ }
+
+ __raw_writew(val, imx_wdt->base + IMX_WDT_WCR);
+}
+
+static int imx_wdt_open(struct inode *inode, struct file *file)
+{
+ if (test_and_set_bit(0, &imx_wdt.status))
+ return -EBUSY;
+
+ file->private_data = &imx_wdt;
+
+ imx_wdt_start(&imx_wdt);
+ return nonseekable_open(inode, file);
+}
+
+static int imx_wdt_close(struct inode *inode, struct file *file)
+{
+ struct imx_wdt_struct *imx_wdt = file->private_data;
+
+#ifndef CONFIG_WATCHDOG_NOWAYOUT
+ /* Disable the watchdog if possible */
+ imx_wdt_stop(imx_wdt);
+#endif
+ clear_bit(0, &imx_wdt->status);
+ return 0;
+}
+
+static int imx_wdt_ioctl(struct inode *inode, struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ struct imx_wdt_struct *imx_wdt = file->private_data;
+ struct watchdog_info *info;
+ void __user *argp = (void __user *)arg;
+ int __user *p = argp;
+ int new_value;
+
+ switch (cmd) {
+ case WDIOC_KEEPALIVE:
+ imx_wdt_ping(imx_wdt);
+ return 0;
+
+ case WDIOC_GETSUPPORT:
+ info = cpu_is_mx1() ? &imx1_wdt_info : &imx2_wdt_info;
+ return copy_to_user(argp, info,
+ sizeof(struct watchdog_info)) ? -EFAULT : 0;
+
+ case WDIOC_SETTIMEOUT:
+ if (!cpu_is_mx1())
+ return -ENOTTY;
+ if (get_user(new_value, p))
+ return -EFAULT;
+ if ((new_value < 1) || (new_value > IMX_WDT1_MAX_TIME))
+ return -EINVAL;
+
+ imx_wdt->timeout = new_value;
+ imx_wdt_start(imx_wdt);
+
+ /* Fallthrough to return current value */
+ case WDIOC_GETTIMEOUT:
+ return put_user(imx_wdt->timeout, p);
+
+ default:
+ return -ENOTTY;
+ }
+}
+
+static ssize_t imx_wdt_write(struct file *file, const char *data,
+ size_t len, loff_t *ppos)
+{
+ struct imx_wdt_struct *imx_wdt = file->private_data;
+
+ imx_wdt_ping(imx_wdt);
+ return len;
+}
+
+static const struct file_operations imx_wdt_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .ioctl = imx_wdt_ioctl,
+ .open = imx_wdt_open,
+ .release = imx_wdt_close,
+ .write = imx_wdt_write,
+};
+
+static struct miscdevice imx_wdt_miscdev = {
+ .minor = WATCHDOG_MINOR,
+ .name = "watchdog",
+ .fops = &imx_wdt_fops,
+};
+
+static void imx_wdt_shutdown(struct platform_device *pdev)
+{
+ struct imx_wdt_struct *imx_wdt = platform_get_drvdata(pdev);
+
+ imx_wdt_stop(imx_wdt);
+}
+
+static int __init imx_wdt_probe(struct platform_device *pdev)
+{
+ int ret;
+ int res_size;
+ struct resource *res;
+ void __iomem *base;
+
+ 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 (!request_mem_region(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;
+ }
+
+ base = ioremap(res->start, res_size);
+ if (!base) {
+ dev_err(&pdev->dev, "ioremap failed\n");
+ ret = -EIO;
+ goto fail0;
+ }
+
+ imx_wdt.clk = clk_get(&pdev->dev, "wdog_clk");
+ if (IS_ERR(imx_wdt.clk)) {
+ dev_err(&pdev->dev, "can't get Watchdog clock\n");
+ ret = PTR_ERR(imx_wdt.clk);
+ goto fail2;
+ }
+ clk_enable(imx_wdt.clk);
+
+ imx_wdt.dev = &pdev->dev;
+ imx_wdt.base = base;
+ imx_wdt.res = res;
+ imx_wdt.timeout = clamp_t(unsigned, timeout, 1,
+ cpu_is_mx1() ? IMX_WDT1_MAX_TIME : IMX_WDT2_MAX_TIME);
+
+ platform_set_drvdata(pdev, &imx_wdt);
+
+ if (imx_wdt_miscdev.parent) {
+ ret = -EBUSY;
+ goto fail3;
+ }
+ imx_wdt_miscdev.parent = &pdev->dev;
+
+ ret = misc_register(&imx_wdt_miscdev);
+ if (ret)
+ goto fail3;
+
+ dev_info(&pdev->dev, "IMX Watchdog Timer enabled\n");
+ return 0;
+
+fail3:
+ clk_disable(imx_wdt.clk);
+ clk_put(imx_wdt.clk);
+fail2:
+ platform_set_drvdata(pdev, NULL);
+ iounmap(base);
+fail0:
+ release_mem_region(res->start, res_size);
+
+ return ret;
+}
+
+static int __exit imx_wdt_remove(struct platform_device *pdev)
+{
+ struct imx_wdt_struct *imx_wdt = platform_get_drvdata(pdev);
+
+ platform_set_drvdata(pdev, NULL);
+ misc_deregister(&imx_wdt_miscdev);
+ iounmap(imx_wdt->base);
+ release_mem_region(imx_wdt->res->start, resource_size(imx_wdt->res));
+ clk_disable(imx_wdt->clk);
+ clk_put(imx_wdt->clk);
+ return 0;
+}
+
+#ifdef CONFIG_PM
+/* Those are only needed for IMX1, other variants do this in hardware */
+static int imx_wdt_suspend(struct platform_device *pdev, pm_message_t message)
+{
+ struct imx_wdt_struct *imx_wdt = platform_get_drvdata(pdev);
+
+ u32 temp = __raw_readw(imx_wdt->base + IMX_WDT_WCR);
+ __raw_writew(temp | IMX_WDT1_WCR_WHALT, imx_wdt->base + IMX_WDT_WCR);
+
+ return 0;
+}
+
+static int imx_wdt_resume(struct platform_device *pdev)
+{
+ struct imx_wdt_struct *imx_wdt = platform_get_drvdata(pdev);
+ u32 temp;
+
+ if (imx_wdt->status) {
+ temp = __raw_readw(imx_wdt->base + IMX_WDT_WCR);
+ __raw_writew(temp & ~IMX_WDT1_WCR_WHALT,
+ imx_wdt->base + IMX_WDT_WCR);
+ }
+
+ return 0;
+}
+#endif
+
+static struct platform_driver imx_wdt_driver = {
+ .probe = imx_wdt_probe,
+ .remove = __exit_p(imx_wdt_remove),
+ .shutdown = imx_wdt_shutdown,
+ .driver = {
+ .name = "imx_wdt",
+ .owner = THIS_MODULE,
+ },
+};
+
+static int __init imx_wdt_init(void)
+{
+#ifdef CONFIG_PM
+ if (cpu_is_mx1()) {
+ imx_wdt_driver.suspend = imx_wdt_suspend;
+ imx_wdt_driver.resume = imx_wdt_resume;
+ }
+#endif
+ return platform_driver_probe(&imx_wdt_driver, imx_wdt_probe);
+}
+module_init(imx_wdt_init);
+
+static void __exit imx_wdt_exit(void)
+{
+ platform_driver_unregister(&imx_wdt_driver);
+}
+module_exit(imx_wdt_exit);
+
+MODULE_AUTHOR("Darius Augulis, Wolfram Sang");
+MODULE_DESCRIPTION("Watchdog driver for IMX");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+MODULE_ALIAS("platform:imx_wdt");
--
1.6.3.3
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