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path: root/drivers/char/watchdog/mv64x60_wdt.c
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Diffstat (limited to 'drivers/char/watchdog/mv64x60_wdt.c')
-rw-r--r--drivers/char/watchdog/mv64x60_wdt.c218
1 files changed, 140 insertions, 78 deletions
diff --git a/drivers/char/watchdog/mv64x60_wdt.c b/drivers/char/watchdog/mv64x60_wdt.c
index b887cdb0133..0365c317f7e 100644
--- a/drivers/char/watchdog/mv64x60_wdt.c
+++ b/drivers/char/watchdog/mv64x60_wdt.c
@@ -23,61 +23,101 @@
#include <linux/watchdog.h>
#include <linux/platform_device.h>
-#include <asm/mv64x60.h>
+#include <linux/mv643xx.h>
#include <asm/uaccess.h>
#include <asm/io.h>
-/* MV64x60 WDC (config) register access definitions */
-#define MV64x60_WDC_CTL1_MASK (3 << 24)
-#define MV64x60_WDC_CTL1(val) ((val & 3) << 24)
-#define MV64x60_WDC_CTL2_MASK (3 << 26)
-#define MV64x60_WDC_CTL2(val) ((val & 3) << 26)
+#define MV64x60_WDT_WDC_OFFSET 0
+
+/*
+ * The watchdog configuration register contains a pair of 2-bit fields,
+ * 1. a reload field, bits 27-26, which triggers a reload of
+ * the countdown register, and
+ * 2. an enable field, bits 25-24, which toggles between
+ * enabling and disabling the watchdog timer.
+ * Bit 31 is a read-only field which indicates whether the
+ * watchdog timer is currently enabled.
+ *
+ * The low 24 bits contain the timer reload value.
+ */
+#define MV64x60_WDC_ENABLE_SHIFT 24
+#define MV64x60_WDC_SERVICE_SHIFT 26
+#define MV64x60_WDC_ENABLED_SHIFT 31
+
+#define MV64x60_WDC_ENABLED_TRUE 1
+#define MV64x60_WDC_ENABLED_FALSE 0
/* Flags bits */
#define MV64x60_WDOG_FLAG_OPENED 0
-#define MV64x60_WDOG_FLAG_ENABLED 1
static unsigned long wdt_flags;
static int wdt_status;
-static void __iomem *mv64x60_regs;
+static void __iomem *mv64x60_wdt_regs;
static int mv64x60_wdt_timeout;
+static int mv64x60_wdt_count;
+static unsigned int bus_clk;
+static char expect_close;
+static DEFINE_SPINLOCK(mv64x60_wdt_spinlock);
+
+static int nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
-static void mv64x60_wdt_reg_write(u32 val)
+static int mv64x60_wdt_toggle_wdc(int enabled_predicate, int field_shift)
{
- /* Allow write only to CTL1 / CTL2 fields, retaining values in
- * other fields.
- */
- u32 data = readl(mv64x60_regs + MV64x60_WDT_WDC);
- data &= ~(MV64x60_WDC_CTL1_MASK | MV64x60_WDC_CTL2_MASK);
- data |= val;
- writel(data, mv64x60_regs + MV64x60_WDT_WDC);
+ u32 data;
+ u32 enabled;
+ int ret = 0;
+
+ spin_lock(&mv64x60_wdt_spinlock);
+ data = readl(mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
+ enabled = (data >> MV64x60_WDC_ENABLED_SHIFT) & 1;
+
+ /* only toggle the requested field if enabled state matches predicate */
+ if ((enabled ^ enabled_predicate) == 0) {
+ /* We write a 1, then a 2 -- to the appropriate field */
+ data = (1 << field_shift) | mv64x60_wdt_count;
+ writel(data, mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
+
+ data = (2 << field_shift) | mv64x60_wdt_count;
+ writel(data, mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
+ ret = 1;
+ }
+ spin_unlock(&mv64x60_wdt_spinlock);
+
+ return ret;
}
static void mv64x60_wdt_service(void)
{
- /* Write 01 followed by 10 to CTL2 */
- mv64x60_wdt_reg_write(MV64x60_WDC_CTL2(0x01));
- mv64x60_wdt_reg_write(MV64x60_WDC_CTL2(0x02));
+ mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_TRUE,
+ MV64x60_WDC_SERVICE_SHIFT);
+}
+
+static void mv64x60_wdt_handler_enable(void)
+{
+ if (mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_FALSE,
+ MV64x60_WDC_ENABLE_SHIFT)) {
+ mv64x60_wdt_service();
+ printk(KERN_NOTICE "mv64x60_wdt: watchdog activated\n");
+ }
}
static void mv64x60_wdt_handler_disable(void)
{
- if (test_and_clear_bit(MV64x60_WDOG_FLAG_ENABLED, &wdt_flags)) {
- /* Write 01 followed by 10 to CTL1 */
- mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x01));
- mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x02));
+ if (mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_TRUE,
+ MV64x60_WDC_ENABLE_SHIFT))
printk(KERN_NOTICE "mv64x60_wdt: watchdog deactivated\n");
- }
}
-static void mv64x60_wdt_handler_enable(void)
+static void mv64x60_wdt_set_timeout(unsigned int timeout)
{
- if (!test_and_set_bit(MV64x60_WDOG_FLAG_ENABLED, &wdt_flags)) {
- /* Write 01 followed by 10 to CTL1 */
- mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x01));
- mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x02));
- printk(KERN_NOTICE "mv64x60_wdt: watchdog activated\n");
- }
+ /* maximum bus cycle count is 0xFFFFFFFF */
+ if (timeout > 0xFFFFFFFF / bus_clk)
+ timeout = 0xFFFFFFFF / bus_clk;
+
+ mv64x60_wdt_count = timeout * bus_clk >> 8;
+ mv64x60_wdt_timeout = timeout;
}
static int mv64x60_wdt_open(struct inode *inode, struct file *file)
@@ -85,21 +125,24 @@ static int mv64x60_wdt_open(struct inode *inode, struct file *file)
if (test_and_set_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags))
return -EBUSY;
- mv64x60_wdt_service();
- mv64x60_wdt_handler_enable();
+ if (nowayout)
+ __module_get(THIS_MODULE);
- nonseekable_open(inode, file);
+ mv64x60_wdt_handler_enable();
- return 0;
+ return nonseekable_open(inode, file);
}
static int mv64x60_wdt_release(struct inode *inode, struct file *file)
{
- mv64x60_wdt_service();
-
-#if !defined(CONFIG_WATCHDOG_NOWAYOUT)
- mv64x60_wdt_handler_disable();
-#endif
+ if (expect_close == 42)
+ mv64x60_wdt_handler_disable();
+ else {
+ printk(KERN_CRIT
+ "mv64x60_wdt: unexpected close, not stopping timer!\n");
+ mv64x60_wdt_service();
+ }
+ expect_close = 0;
clear_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags);
@@ -109,8 +152,22 @@ static int mv64x60_wdt_release(struct inode *inode, struct file *file)
static ssize_t mv64x60_wdt_write(struct file *file, const char __user *data,
size_t len, loff_t * ppos)
{
- if (len)
+ if (len) {
+ if (!nowayout) {
+ size_t i;
+
+ expect_close = 0;
+
+ for (i = 0; i != len; i++) {
+ char c;
+ if(get_user(c, data + i))
+ return -EFAULT;
+ if (c == 'V')
+ expect_close = 42;
+ }
+ }
mv64x60_wdt_service();
+ }
return len;
}
@@ -119,9 +176,12 @@ static int mv64x60_wdt_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
int timeout;
+ int options;
void __user *argp = (void __user *)arg;
static struct watchdog_info info = {
- .options = WDIOF_KEEPALIVEPING,
+ .options = WDIOF_SETTIMEOUT |
+ WDIOF_MAGICCLOSE |
+ WDIOF_KEEPALIVEPING,
.firmware_version = 0,
.identity = "MV64x60 watchdog",
};
@@ -143,7 +203,15 @@ static int mv64x60_wdt_ioctl(struct inode *inode, struct file *file,
return -EOPNOTSUPP;
case WDIOC_SETOPTIONS:
- return -EOPNOTSUPP;
+ if (get_user(options, (int __user *)argp))
+ return -EFAULT;
+
+ if (options & WDIOS_DISABLECARD)
+ mv64x60_wdt_handler_disable();
+
+ if (options & WDIOS_ENABLECARD)
+ mv64x60_wdt_handler_enable();
+ break;
case WDIOC_KEEPALIVE:
mv64x60_wdt_service();
@@ -151,11 +219,13 @@ static int mv64x60_wdt_ioctl(struct inode *inode, struct file *file,
break;
case WDIOC_SETTIMEOUT:
- return -EOPNOTSUPP;
+ if (get_user(timeout, (int __user *)argp))
+ return -EFAULT;
+ mv64x60_wdt_set_timeout(timeout);
+ /* Fall through */
case WDIOC_GETTIMEOUT:
- timeout = mv64x60_wdt_timeout * HZ;
- if (put_user(timeout, (int __user *)argp))
+ if (put_user(mv64x60_wdt_timeout, (int __user *)argp))
return -EFAULT;
break;
@@ -184,18 +254,33 @@ static struct miscdevice mv64x60_wdt_miscdev = {
static int __devinit mv64x60_wdt_probe(struct platform_device *dev)
{
struct mv64x60_wdt_pdata *pdata = dev->dev.platform_data;
- int bus_clk = 133;
+ struct resource *r;
+ int timeout = 10;
- mv64x60_wdt_timeout = 10;
+ bus_clk = 133; /* in MHz */
if (pdata) {
- mv64x60_wdt_timeout = pdata->timeout;
+ timeout = pdata->timeout;
bus_clk = pdata->bus_clk;
}
- mv64x60_regs = mv64x60_get_bridge_vbase();
+ /* Since bus_clk is truncated MHz, actual frequency could be
+ * up to 1MHz higher. Round up, since it's better to time out
+ * too late than too soon.
+ */
+ bus_clk++;
+ bus_clk *= 1000000; /* convert to Hz */
+
+ r = platform_get_resource(dev, IORESOURCE_MEM, 0);
+ if (!r)
+ return -ENODEV;
- writel((mv64x60_wdt_timeout * (bus_clk * 1000000)) >> 8,
- mv64x60_regs + MV64x60_WDT_WDC);
+ mv64x60_wdt_regs = ioremap(r->start, r->end - r->start + 1);
+ if (mv64x60_wdt_regs == NULL)
+ return -ENOMEM;
+
+ mv64x60_wdt_set_timeout(timeout);
+
+ mv64x60_wdt_handler_disable(); /* in case timer was already running */
return misc_register(&mv64x60_wdt_miscdev);
}
@@ -204,9 +289,10 @@ static int __devexit mv64x60_wdt_remove(struct platform_device *dev)
{
misc_deregister(&mv64x60_wdt_miscdev);
- mv64x60_wdt_service();
mv64x60_wdt_handler_disable();
+ iounmap(mv64x60_wdt_regs);
+
return 0;
}
@@ -219,40 +305,16 @@ static struct platform_driver mv64x60_wdt_driver = {
},
};
-static struct platform_device *mv64x60_wdt_dev;
-
static int __init mv64x60_wdt_init(void)
{
- int ret;
-
printk(KERN_INFO "MV64x60 watchdog driver\n");
- mv64x60_wdt_dev = platform_device_alloc(MV64x60_WDT_NAME, -1);
- if (!mv64x60_wdt_dev) {
- ret = -ENOMEM;
- goto out;
- }
-
- ret = platform_device_add(mv64x60_wdt_dev);
- if (ret) {
- platform_device_put(mv64x60_wdt_dev);
- goto out;
- }
-
- ret = platform_driver_register(&mv64x60_wdt_driver);
- if (ret) {
- platform_device_unregister(mv64x60_wdt_dev);
- goto out;
- }
-
- out:
- return ret;
+ return platform_driver_register(&mv64x60_wdt_driver);
}
static void __exit mv64x60_wdt_exit(void)
{
platform_driver_unregister(&mv64x60_wdt_driver);
- platform_device_unregister(mv64x60_wdt_dev);
}
module_init(mv64x60_wdt_init);