[PATCH (v2) 10/11] watchdog: bcm63xx_wdt: Use bcm63xx_timer interrupt directly

[Simon Arlott <simon@fire.lp0.eu>]

There is only one user of bcm63xx_timer and that is the watchdog.
To allow the watchdog driver to be used on machine types other than
mach-bcm63xx, it needs to use an interrupt instead of a custom register
function.

Modify bcm63xx_timer to only disable the timers (so that they don't
interfere with the watchdog if an interrupt occurs) and remove its
exported functions.

Use the timer interrupt directly in bcm63xx_wdt.

Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
---
Patch 7 split into two patches.

There was no change to patch 8/10 which is now 9/11.

On 25/11/15 22:40, Simon Arlott wrote:
> Moved registration of the timer in the probe function to after register
> of the watchdog device because the interrupt handler uses wdd->dev.

This patch (9/10 now 10/11) was affected by this reordering, and an
earlier change to use "hw" instead of "wdd" as the interrupt data.

 arch/mips/bcm63xx/dev-wdt.c                        |   7 +
 arch/mips/bcm63xx/timer.c                          | 181 +--------------------
 arch/mips/include/asm/mach-bcm63xx/bcm63xx_timer.h |  11 --
 drivers/watchdog/bcm63xx_wdt.c                     |  41 +++--
 4 files changed, 36 insertions(+), 204 deletions(-)
 delete mode 100644 arch/mips/include/asm/mach-bcm63xx/bcm63xx_timer.h

diff --git a/arch/mips/bcm63xx/dev-wdt.c b/arch/mips/bcm63xx/dev-wdt.c
index 2a2346a..a7a5497 100644
--- a/arch/mips/bcm63xx/dev-wdt.c
+++ b/arch/mips/bcm63xx/dev-wdt.c
@@ -17,6 +17,11 @@ static struct resource wdt_resources[] = {
 		.end		= -1, /* filled at runtime */
 		.flags		= IORESOURCE_MEM,
 	},
+	{
+		.start		= -1, /* filled at runtime */
+		.end		= -1, /* filled at runtime */
+		.flags		= IORESOURCE_IRQ,
+	},
 };
 
 static struct platform_device bcm63xx_wdt_device = {
@@ -32,6 +37,8 @@ int __init bcm63xx_wdt_register(void)
 	wdt_resources[0].end = wdt_resources[0].start;
 	wdt_resources[0].end += RSET_WDT_SIZE - 1;
 
+	wdt_resources[1].start = bcm63xx_get_irq_number(IRQ_TIMER);
+
 	return platform_device_register(&bcm63xx_wdt_device);
 }
 arch_initcall(bcm63xx_wdt_register);
diff --git a/arch/mips/bcm63xx/timer.c b/arch/mips/bcm63xx/timer.c
index 2110359..9c7b41a6 100644
--- a/arch/mips/bcm63xx/timer.c
+++ b/arch/mips/bcm63xx/timer.c
@@ -9,196 +9,23 @@
 #include <linux/kernel.h>
 #include <linux/err.h>
 #include <linux/module.h>
-#include <linux/spinlock.h>
-#include <linux/interrupt.h>
-#include <linux/clk.h>
 #include <bcm63xx_cpu.h>
 #include <bcm63xx_io.h>
-#include <bcm63xx_timer.h>
 #include <bcm63xx_regs.h>
 
-static DEFINE_RAW_SPINLOCK(timer_reg_lock);
-static DEFINE_RAW_SPINLOCK(timer_data_lock);
-static struct clk *periph_clk;
-
-static struct timer_data {
-	void	(*cb)(void *);
-	void	*data;
-} timer_data[BCM63XX_TIMER_COUNT];
-
-static irqreturn_t timer_interrupt(int irq, void *dev_id)
-{
-	u32 stat;
-	int i;
-
-	raw_spin_lock(&timer_reg_lock);
-	stat = bcm_timer_readl(TIMER_IRQSTAT_REG);
-	bcm_timer_writel(stat, TIMER_IRQSTAT_REG);
-	raw_spin_unlock(&timer_reg_lock);
-
-	for (i = 0; i < BCM63XX_TIMER_COUNT; i++) {
-		if (!(stat & TIMER_IRQSTAT_TIMER_CAUSE(i)))
-			continue;
-
-		raw_spin_lock(&timer_data_lock);
-		if (!timer_data[i].cb) {
-			raw_spin_unlock(&timer_data_lock);
-			continue;
-		}
-
-		timer_data[i].cb(timer_data[i].data);
-		raw_spin_unlock(&timer_data_lock);
-	}
-
-	return IRQ_HANDLED;
-}
-
-int bcm63xx_timer_enable(int id)
-{
-	u32 reg;
-	unsigned long flags;
-
-	if (id >= BCM63XX_TIMER_COUNT)
-		return -EINVAL;
-
-	raw_spin_lock_irqsave(&timer_reg_lock, flags);
-
-	reg = bcm_timer_readl(TIMER_CTLx_REG(id));
-	reg |= TIMER_CTL_ENABLE_MASK;
-	bcm_timer_writel(reg, TIMER_CTLx_REG(id));
-
-	reg = bcm_timer_readl(TIMER_IRQSTAT_REG);
-	reg |= TIMER_IRQSTAT_TIMER_IR_EN(id);
-	bcm_timer_writel(reg, TIMER_IRQSTAT_REG);
-
-	raw_spin_unlock_irqrestore(&timer_reg_lock, flags);
-	return 0;
-}
-
-EXPORT_SYMBOL(bcm63xx_timer_enable);
-
-int bcm63xx_timer_disable(int id)
+static int bcm63xx_timer_init(void)
 {
 	u32 reg;
-	unsigned long flags;
-
-	if (id >= BCM63XX_TIMER_COUNT)
-		return -EINVAL;
-
-	raw_spin_lock_irqsave(&timer_reg_lock, flags);
-
-	reg = bcm_timer_readl(TIMER_CTLx_REG(id));
-	reg &= ~TIMER_CTL_ENABLE_MASK;
-	bcm_timer_writel(reg, TIMER_CTLx_REG(id));
-
-	reg = bcm_timer_readl(TIMER_IRQSTAT_REG);
-	reg &= ~TIMER_IRQSTAT_TIMER_IR_EN(id);
-	bcm_timer_writel(reg, TIMER_IRQSTAT_REG);
-
-	raw_spin_unlock_irqrestore(&timer_reg_lock, flags);
-	return 0;
-}
-
-EXPORT_SYMBOL(bcm63xx_timer_disable);
-
-int bcm63xx_timer_register(int id, void (*callback)(void *data), void *data)
-{
-	unsigned long flags;
-	int ret;
-
-	if (id >= BCM63XX_TIMER_COUNT || !callback)
-		return -EINVAL;
-
-	ret = 0;
-	raw_spin_lock_irqsave(&timer_data_lock, flags);
-	if (timer_data[id].cb) {
-		ret = -EBUSY;
-		goto out;
-	}
-
-	timer_data[id].cb = callback;
-	timer_data[id].data = data;
-
-out:
-	raw_spin_unlock_irqrestore(&timer_data_lock, flags);
-	return ret;
-}
-
-EXPORT_SYMBOL(bcm63xx_timer_register);
-
-void bcm63xx_timer_unregister(int id)
-{
-	unsigned long flags;
-
-	if (id >= BCM63XX_TIMER_COUNT)
-		return;
-
-	raw_spin_lock_irqsave(&timer_data_lock, flags);
-	timer_data[id].cb = NULL;
-	raw_spin_unlock_irqrestore(&timer_data_lock, flags);
-}
-
-EXPORT_SYMBOL(bcm63xx_timer_unregister);
-
-unsigned int bcm63xx_timer_countdown(unsigned int countdown_us)
-{
-	return (clk_get_rate(periph_clk) / (1000 * 1000)) * countdown_us;
-}
-
-EXPORT_SYMBOL(bcm63xx_timer_countdown);
-
-int bcm63xx_timer_set(int id, int monotonic, unsigned int countdown_us)
-{
-	u32 reg, countdown;
-	unsigned long flags;
-
-	if (id >= BCM63XX_TIMER_COUNT)
-		return -EINVAL;
-
-	countdown = bcm63xx_timer_countdown(countdown_us);
-	if (countdown & ~TIMER_CTL_COUNTDOWN_MASK)
-		return -EINVAL;
-
-	raw_spin_lock_irqsave(&timer_reg_lock, flags);
-	reg = bcm_timer_readl(TIMER_CTLx_REG(id));
-
-	if (monotonic)
-		reg &= ~TIMER_CTL_MONOTONIC_MASK;
-	else
-		reg |= TIMER_CTL_MONOTONIC_MASK;
-
-	reg &= ~TIMER_CTL_COUNTDOWN_MASK;
-	reg |= countdown;
-	bcm_timer_writel(reg, TIMER_CTLx_REG(id));
-
-	raw_spin_unlock_irqrestore(&timer_reg_lock, flags);
-	return 0;
-}
-
-EXPORT_SYMBOL(bcm63xx_timer_set);
-
-int bcm63xx_timer_init(void)
-{
-	int ret, irq;
-	u32 reg;
 
+	/* Disable all timers so that they won't interfere with use of the
+	 * timer interrupt by the watchdog.
+	 */
 	reg = bcm_timer_readl(TIMER_IRQSTAT_REG);
 	reg &= ~TIMER_IRQSTAT_TIMER0_IR_EN;
 	reg &= ~TIMER_IRQSTAT_TIMER1_IR_EN;
 	reg &= ~TIMER_IRQSTAT_TIMER2_IR_EN;
 	bcm_timer_writel(reg, TIMER_IRQSTAT_REG);
 
-	periph_clk = clk_get(NULL, "periph");
-	if (IS_ERR(periph_clk))
-		return -ENODEV;
-
-	irq = bcm63xx_get_irq_number(IRQ_TIMER);
-	ret = request_irq(irq, timer_interrupt, 0, "bcm63xx_timer", NULL);
-	if (ret) {
-		pr_err("%s: failed to register irq\n", __func__);
-		return ret;
-	}
-
 	return 0;
 }
 
diff --git a/arch/mips/include/asm/mach-bcm63xx/bcm63xx_timer.h b/arch/mips/include/asm/mach-bcm63xx/bcm63xx_timer.h
deleted file mode 100644
index c0fce83..0000000
--- a/arch/mips/include/asm/mach-bcm63xx/bcm63xx_timer.h
+++ /dev/null
@@ -1,11 +0,0 @@
-#ifndef BCM63XX_TIMER_H_
-#define BCM63XX_TIMER_H_
-
-int bcm63xx_timer_register(int id, void (*callback)(void *data), void *data);
-void bcm63xx_timer_unregister(int id);
-int bcm63xx_timer_set(int id, int monotonic, unsigned int countdown_us);
-int bcm63xx_timer_enable(int id);
-int bcm63xx_timer_disable(int id);
-unsigned int bcm63xx_timer_countdown(unsigned int countdown_us);
-
-#endif /* !BCM63XX_TIMER_H_ */
diff --git a/drivers/watchdog/bcm63xx_wdt.c b/drivers/watchdog/bcm63xx_wdt.c
index f409523..fa6c28b 100644
--- a/drivers/watchdog/bcm63xx_wdt.c
+++ b/drivers/watchdog/bcm63xx_wdt.c
@@ -17,6 +17,7 @@
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/errno.h>
+#include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -28,9 +29,6 @@
 #include <linux/resource.h>
 #include <linux/platform_device.h>
 
-#include <bcm63xx_regs.h>
-#include <bcm63xx_timer.h>
-
 #define PFX KBUILD_MODNAME
 
 #define WDT_CLK_NAME		"periph"
@@ -41,6 +39,7 @@ struct bcm63xx_wdt_hw {
 	void __iomem *regs;
 	struct clk *clk;
 	unsigned long clock_hz;
+	int irq;
 	bool running;
 };
 
@@ -99,7 +98,7 @@ static int bcm63xx_wdt_set_timeout(struct watchdog_device *wdd,
 }
 
 /* The watchdog interrupt occurs when half the timeout is remaining */
-static void bcm63xx_wdt_isr(void *data)
+static irqreturn_t bcm63xx_wdt_interrupt(int irq, void *data)
 {
 	struct bcm63xx_wdt_hw *hw = data;
 	unsigned long flags;
@@ -139,6 +138,7 @@ static void bcm63xx_wdt_isr(void *data)
 			"warning timer fired, reboot in %ums\n", ms);
 	}
 	raw_spin_unlock_irqrestore(&hw->lock, flags);
+	return IRQ_HANDLED;
 }
 
 static struct watchdog_ops bcm63xx_wdt_ops = {
@@ -237,24 +237,31 @@ static int bcm63xx_wdt_probe(struct platform_device *pdev)
 		goto disable_clk;
 	}
 
-	ret = bcm63xx_timer_register(TIMER_WDT_ID, bcm63xx_wdt_isr, hw);
-	if (ret < 0) {
-		dev_err(&pdev->dev, "failed to register wdt timer isr\n");
-		goto unregister_watchdog;
+	hw->irq = platform_get_irq(pdev, 0);
+	if (hw->irq >= 0) {
+		ret = devm_request_irq(&pdev->dev, hw->irq,
+			bcm63xx_wdt_interrupt, IRQF_TIMER,
+			dev_name(&pdev->dev), hw);
+		if (ret)
+			hw->irq = -1;
 	}
 
-	dev_info(&pdev->dev,
-		"%s at MMIO 0x%p (timeout = %us, max_timeout = %us)",
-		dev_name(wdd->dev), hw->regs,
-		wdd->timeout, wdd->max_timeout);
+	if (hw->irq >= 0) {
+		dev_info(&pdev->dev,
+			"%s at MMIO 0x%p (irq = %d, timeout = %us, max_timeout = %us)",
+			dev_name(wdd->dev), hw->regs, hw->irq,
+			wdd->timeout, wdd->max_timeout);
+	} else {
+		dev_info(&pdev->dev,
+			"%s at MMIO 0x%p (timeout = %us, max_timeout = %us)",
+			dev_name(wdd->dev), hw->regs,
+			wdd->timeout, wdd->max_timeout);
+	}
 
 	if (hw->running)
 		dev_alert(wdd->dev, "running, reboot in %us\n", timeleft);
 	return 0;
 
-unregister_watchdog:
-	watchdog_unregister_device(wdd);
-
 disable_clk:
 	clk_disable_unprepare(hw->clk);
 	return ret;
@@ -264,7 +271,9 @@ static int bcm63xx_wdt_remove(struct platform_device *pdev)
 {
 	struct bcm63xx_wdt_hw *hw = platform_get_drvdata(pdev);
 
-	bcm63xx_timer_unregister(TIMER_WDT_ID);
+	if (hw->irq >= 0)
+		devm_free_irq(&pdev->dev, hw->irq, hw);
+
 	watchdog_unregister_device(&hw->wdd);
 	clk_disable_unprepare(hw->clk);
 	return 0;
-- 
2.1.4

-- 
Simon Arlott