[WATCHDOG] davinci watchdog driver

Add watchdog support for TI Davinci DM644x/DM646x processors.

Signed-off-by: Vladimir Barinov <vbarinov@ru.mvista.com> 
Signed-off-by: Kevin Hilman <khilman@mvista.com> 
Signed-off-by: Wim Van Sebroeck <wim@iguana.be> 

3 files changed, 297 insertions, 0 deletions

diff --git a/drivers/char/watchdog/Kconfig b/drivers/char/watchdog/Kconfig
index 2dfaf96..d9c2eb0 100644
--- a/drivers/char/watchdog/Kconfig
+++ b/drivers/char/watchdog/Kconfig
@@ -203,6 +203,18 @@ config IOP_WATCHDOG
 	  operating as an Root Complex and/or Central Resource, the PCI-X
 	  and/or PCIe busses will also be reset.  THIS IS A VERY BIG HAMMER.
 
+config DAVINCI_WATCHDOG
+	tristate "DaVinci watchdog"
+	depends on WATCHDOG && ARCH_DAVINCI
+	help
+	  Say Y here if to include support for the watchdog timer
+	  in the DaVinci DM644x/DM646x processors.
+	  To compile this driver as a module, choose M here: the
+	  module will be called davinci_wdt.
+
+	  NOTE: once enabled, this timer cannot be disabled.
+	  Say N if you are unsure.
+
 # AVR32 Architecture
 
 config AT32AP700X_WDT
diff --git a/drivers/char/watchdog/Makefile b/drivers/char/watchdog/Makefile
index 6f2342e..edbf30e 100644
--- a/drivers/char/watchdog/Makefile
+++ b/drivers/char/watchdog/Makefile
@@ -36,6 +36,7 @@ obj-$(CONFIG_MPCORE_WATCHDOG) += mpcore_wdt.o
 obj-$(CONFIG_EP93XX_WATCHDOG) += ep93xx_wdt.o
 obj-$(CONFIG_PNX4008_WATCHDOG) += pnx4008_wdt.o
 obj-$(CONFIG_IOP_WATCHDOG) += iop_wdt.o
+obj-$(CONFIG_DAVINCI_WATCHDOG) += davinci_wdt.o
 
 # AVR32 Architecture
 obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
diff --git a/drivers/char/watchdog/davinci_wdt.c b/drivers/char/watchdog/davinci_wdt.c
new file mode 100644
index 0000000..27b4f66
--- /dev/null
+++ b/drivers/char/watchdog/davinci_wdt.c
@@ -0,0 +1,284 @@
+/*
+ * drivers/char/watchdog/davinci_wdt.c
+ *
+ * Watchdog driver for DaVinci DM644x/DM646x processors
+ *
+ * Copyright (C) 2006 Texas Instruments.
+ *
+ * 2007 (c) MontaVista Software, Inc. This file is licensed under
+ * the terms of the GNU General Public License version 2. This program
+ * is licensed "as is" without any warranty of any kind, whether express
+ * or implied.
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/init.h>
+#include <linux/bitops.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+
+#include <asm/hardware.h>
+#include <asm/uaccess.h>
+#include <asm/io.h>
+
+#define MODULE_NAME "DAVINCI-WDT: "
+
+#define DEFAULT_HEARTBEAT 60
+#define MAX_HEARTBEAT     600	/* really the max margin is 264/27MHz*/
+
+/* Timer register set definition */
+#define PID12	(0x0)
+#define EMUMGT	(0x4)
+#define TIM12	(0x10)
+#define TIM34	(0x14)
+#define PRD12	(0x18)
+#define PRD34	(0x1C)
+#define TCR	(0x20)
+#define TGCR	(0x24)
+#define WDTCR	(0x28)
+
+/* TCR bit definitions */
+#define ENAMODE12_DISABLED	(0 << 6)
+#define ENAMODE12_ONESHOT	(1 << 6)
+#define ENAMODE12_PERIODIC	(2 << 6)
+
+/* TGCR bit definitions */
+#define TIM12RS_UNRESET		(1 << 0)
+#define TIM34RS_UNRESET		(1 << 1)
+#define TIMMODE_64BIT_WDOG      (2 << 2)
+
+/* WDTCR bit definitions */
+#define WDEN			(1 << 14)
+#define WDFLAG			(1 << 15)
+#define WDKEY_SEQ0		(0xa5c6 << 16)
+#define WDKEY_SEQ1		(0xda7e << 16)
+
+static int heartbeat = DEFAULT_HEARTBEAT;
+
+static spinlock_t io_lock;
+static unsigned long wdt_status;
+#define WDT_IN_USE        0
+#define WDT_OK_TO_CLOSE   1
+#define WDT_REGION_INITED 2
+#define WDT_DEVICE_INITED 3
+
+static struct resource	*wdt_mem;
+static void __iomem	*wdt_base;
+
+static void wdt_service(void)
+{
+	spin_lock(&io_lock);
+
+	/* put watchdog in service state */
+	davinci_writel(WDKEY_SEQ0, wdt_base + WDTCR);
+	/* put watchdog in active state */
+	davinci_writel(WDKEY_SEQ1, wdt_base + WDTCR);
+
+	spin_unlock(&io_lock);
+}
+
+static void wdt_enable(void)
+{
+	u32 tgcr;
+	u32 timer_margin;
+
+	spin_lock(&io_lock);
+
+	/* disable, internal clock source */
+	davinci_writel(0, wdt_base + TCR);
+	/* reset timer, set mode to 64-bit watchdog, and unreset */
+	davinci_writel(0, wdt_base + TGCR);
+	tgcr = TIMMODE_64BIT_WDOG | TIM12RS_UNRESET | TIM34RS_UNRESET;
+	davinci_writel(tgcr, wdt_base + TGCR);
+	/* clear counter regs */
+	davinci_writel(0, wdt_base + TIM12);
+	davinci_writel(0, wdt_base + TIM34);
+	/* set timeout period */
+	timer_margin = (((u64)heartbeat * CLOCK_TICK_RATE) & 0xffffffff);
+	davinci_writel(timer_margin, wdt_base + PRD12);
+	timer_margin = (((u64)heartbeat * CLOCK_TICK_RATE) >> 32);
+	davinci_writel(timer_margin, wdt_base + PRD34);
+	/* enable run continuously */
+	davinci_writel(ENAMODE12_PERIODIC, wdt_base + TCR);
+	/* Once the WDT is in pre-active state write to
+	 * TIM12, TIM34, PRD12, PRD34, TCR, TGCR, WDTCR are
+	 * write protected (except for the WDKEY field)
+	 */
+	/* put watchdog in pre-active state */
+	davinci_writel(WDKEY_SEQ0 | WDEN, wdt_base + WDTCR);
+	/* put watchdog in active state */
+	davinci_writel(WDKEY_SEQ1 | WDEN, wdt_base + WDTCR);
+
+	spin_unlock(&io_lock);
+}
+
+static int davinci_wdt_open(struct inode *inode, struct file *file)
+{
+	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
+		return -EBUSY;
+
+	wdt_enable();
+
+	return nonseekable_open(inode, file);
+}
+
+static ssize_t
+davinci_wdt_write(struct file *file, const char *data, size_t len,
+		  loff_t *ppos)
+{
+	/*  Can't seek (pwrite) on this device  */
+	if (ppos != &file->f_pos)
+		return -ESPIPE;
+
+	if (len)
+		wdt_service();
+
+	return len;
+}
+
+static struct watchdog_info ident = {
+	.options = WDIOF_CARDRESET | WDIOF_KEEPALIVEPING,
+	.identity = "DaVinci Watchdog",
+};
+
+static int
+davinci_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
+		  unsigned long arg)
+{
+	int ret = -ENOTTY;
+
+	switch (cmd) {
+	case WDIOC_GETSUPPORT:
+		ret = copy_to_user((struct watchdog_info *)arg, &ident,
+				   sizeof(ident)) ? -EFAULT : 0;
+		break;
+
+	case WDIOC_GETSTATUS:
+		ret = put_user(0, (int *)arg);
+		break;
+
+	case WDIOC_GETTIMEOUT:
+		ret = put_user(heartbeat, (int *)arg);
+		break;
+
+	case WDIOC_KEEPALIVE:
+		wdt_service();
+		ret = 0;
+		break;
+	}
+	return ret;
+}
+
+static int davinci_wdt_release(struct inode *inode, struct file *file)
+{
+	wdt_service();
+	clear_bit(WDT_IN_USE, &wdt_status);
+
+	return 0;
+}
+
+static const struct file_operations davinci_wdt_fops = {
+	.owner = THIS_MODULE,
+	.llseek = no_llseek,
+	.write = davinci_wdt_write,
+	.ioctl = davinci_wdt_ioctl,
+	.open = davinci_wdt_open,
+	.release = davinci_wdt_release,
+};
+
+static struct miscdevice davinci_wdt_miscdev = {
+	.minor = WATCHDOG_MINOR,
+	.name = "watchdog",
+	.fops = &davinci_wdt_fops,
+};
+
+static int davinci_wdt_probe(struct platform_device *pdev)
+{
+	int ret = 0, size;
+	struct resource *res;
+
+	spin_lock_init(&io_lock);
+
+	if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
+		heartbeat = DEFAULT_HEARTBEAT;
+
+	printk(KERN_INFO MODULE_NAME
+		"DaVinci Watchdog Timer: heartbeat %d sec\n", heartbeat);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (res == NULL) {
+		printk(KERN_INFO MODULE_NAME
+			"failed to get memory region resource\n");
+		return -ENOENT;
+	}
+
+	size = res->end - res->start + 1;
+	wdt_mem = request_mem_region(res->start, size, pdev->name);
+
+	if (wdt_mem == NULL) {
+		printk(KERN_INFO MODULE_NAME "failed to get memory region\n");
+		return -ENOENT;
+	}
+	wdt_base = (void __iomem *)(res->start);
+
+	ret = misc_register(&davinci_wdt_miscdev);
+	if (ret < 0) {
+		printk(KERN_ERR MODULE_NAME "cannot register misc device\n");
+		release_resource(wdt_mem);
+		kfree(wdt_mem);
+	} else {
+		set_bit(WDT_DEVICE_INITED, &wdt_status);
+	}
+
+	return ret;
+}
+
+static int davinci_wdt_remove(struct platform_device *pdev)
+{
+	misc_deregister(&davinci_wdt_miscdev);
+	if (wdt_mem) {
+		release_resource(wdt_mem);
+		kfree(wdt_mem);
+		wdt_mem = NULL;
+	}
+	return 0;
+}
+
+static struct platform_driver platform_wdt_driver = {
+	.driver = {
+		.name = "watchdog",
+	},
+	.probe = davinci_wdt_probe,
+	.remove = davinci_wdt_remove,
+};
+
+static int __init davinci_wdt_init(void)
+{
+	return platform_driver_register(&platform_wdt_driver);
+}
+
+static void __exit davinci_wdt_exit(void)
+{
+	return platform_driver_unregister(&platform_wdt_driver);
+}
+
+module_init(davinci_wdt_init);
+module_exit(davinci_wdt_exit);
+
+MODULE_AUTHOR("Texas Instruments");
+MODULE_DESCRIPTION("DaVinci Watchdog Driver");
+
+module_param(heartbeat, int, 0);
+MODULE_PARM_DESC(heartbeat,
+		 "Watchdog heartbeat period in seconds from 1 to "
+		 __MODULE_STRING(MAX_HEARTBEAT) ", default "
+		 __MODULE_STRING(DEFAULT_HEARTBEAT));
+
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);