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Commit f1869994 authored by Dale Farnsworth's avatar Dale Farnsworth Committed by Wim Van Sebroeck
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[WATCHDOG] mv64x60_wdt: Rework the timeout register manipulation 



Consolidate the timeout config register modification into a single
function.  Also, use the enabled flag in the config register to
determine whether the timer is enabled instead of a separately
maintained flag, MV64x60_WDOG_FLAG_ENABLED.

Add spinlock protection around enabling/disabling the watchdog timer.

Signed-off-by: default avatarDale Farnsworth <dale@farnsworth.org>
Signed-off-by: default avatarWim Van Sebroeck <wim@iguana.be>
parent 2422df5e

drivers/char/watchdog/mv64x60_wdt.c

+54 −36
Original line number Diff line number Diff line
@@ -29,75 +29,95 @@ 


#define MV64x60_WDT_WDC_OFFSET	0



/* 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)

/*

 * 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_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_wdt_regs + MV64x60_WDT_WDC_OFFSET);

	data &= ~(MV64x60_WDC_CTL1_MASK | MV64x60_WDC_CTL2_MASK);

	data |= val;

	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);



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));

	return ret;

}



static void mv64x60_wdt_handler_disable(void)

static void mv64x60_wdt_service(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));

		printk(KERN_NOTICE "mv64x60_wdt: watchdog deactivated\n");

	}

	mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_TRUE,

			       MV64x60_WDC_SERVICE_SHIFT);

}



static void mv64x60_wdt_handler_enable(void)

{

	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));

	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_set_timeout(int timeout)

static void mv64x60_wdt_handler_disable(void)

{

	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_set_timeout(unsigned int timeout)

{

	/* 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;

	writel((timeout * bus_clk) >> 8,

	       mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);

	mv64x60_wdt_service();

}



static int mv64x60_wdt_open(struct inode *inode, struct file *file)
@@ -108,7 +128,6 @@ static int mv64x60_wdt_open(struct inode *inode, struct file *file) 
	if (nowayout)

		__module_get(THIS_MODULE);



	mv64x60_wdt_service();

	mv64x60_wdt_handler_enable();



	return nonseekable_open(inode, file);
@@ -270,7 +289,6 @@ 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);