[PATCH v4 04/18] watchdog: orion: Use atomic access for shared registers
From: Ezequiel Garcia <hidden>
Date: 2014-01-22 23:05:01
Also in:
linux-devicetree, linux-watchdog
Subsystem:
the rest, watchdog device drivers · Maintainers:
Linus Torvalds, Wim Van Sebroeck, Guenter Roeck
Possibly related (same subject, not in this thread)
- 2014-01-25 · Re: [PATCH v4 04/18] watchdog: orion: Use atomic access for shared registers · Guenter Roeck <hidden>
Since the timer control register is shared with the clocksource driver, use the recently introduced atomic_io_clear_set() to access such register. Given the watchdog core already provides serialization for all the watchdog ops, this commit allows to remove the spinlock entirely. Signed-off-by: Ezequiel Garcia <redacted> --- drivers/watchdog/orion_wdt.c | 42 +++++------------------------------------- 1 file changed, 5 insertions(+), 37 deletions(-)
diff --git a/drivers/watchdog/orion_wdt.c b/drivers/watchdog/orion_wdt.c
index 7f19fa3..b92a991 100644
--- a/drivers/watchdog/orion_wdt.c
+++ b/drivers/watchdog/orion_wdt.c@@ -20,7 +20,6 @@ #include <linux/watchdog.h> #include <linux/init.h> #include <linux/io.h> -#include <linux/spinlock.h> #include <linux/clk.h> #include <linux/err.h> #include <linux/of.h>
@@ -46,25 +45,16 @@ static unsigned int wdt_max_duration; /* (seconds) */ static struct clk *clk; static unsigned int wdt_tclk; static void __iomem *wdt_reg; -static DEFINE_SPINLOCK(wdt_lock); static int orion_wdt_ping(struct watchdog_device *wdt_dev) { - spin_lock(&wdt_lock); - /* Reload watchdog duration */ writel(wdt_tclk * wdt_dev->timeout, wdt_reg + WDT_VAL); - - spin_unlock(&wdt_lock); return 0; } static int orion_wdt_start(struct watchdog_device *wdt_dev) { - u32 reg; - - spin_lock(&wdt_lock); - /* Set watchdog duration */ writel(wdt_tclk * wdt_dev->timeout, wdt_reg + WDT_VAL);
@@ -72,48 +62,26 @@ static int orion_wdt_start(struct watchdog_device *wdt_dev) writel(~WDT_INT_REQ, BRIDGE_CAUSE); /* Enable watchdog timer */ - reg = readl(wdt_reg + TIMER_CTRL); - reg |= WDT_EN; - writel(reg, wdt_reg + TIMER_CTRL); + atomic_io_modify(wdt_reg + TIMER_CTRL, WDT_EN, WDT_EN); /* Enable reset on watchdog */ - reg = readl(RSTOUTn_MASK); - reg |= WDT_RESET_OUT_EN; - writel(reg, RSTOUTn_MASK); - - spin_unlock(&wdt_lock); + atomic_io_modify(RSTOUTn_MASK, WDT_RESET_OUT_EN, WDT_RESET_OUT_EN); return 0; } static int orion_wdt_stop(struct watchdog_device *wdt_dev) { - u32 reg; - - spin_lock(&wdt_lock); - /* Disable reset on watchdog */ - reg = readl(RSTOUTn_MASK); - reg &= ~WDT_RESET_OUT_EN; - writel(reg, RSTOUTn_MASK); + atomic_io_modify(RSTOUTn_MASK, WDT_RESET_OUT_EN, 0); /* Disable watchdog timer */ - reg = readl(wdt_reg + TIMER_CTRL); - reg &= ~WDT_EN; - writel(reg, wdt_reg + TIMER_CTRL); - - spin_unlock(&wdt_lock); + atomic_io_modify(wdt_reg + TIMER_CTRL, WDT_EN, 0); return 0; } static unsigned int orion_wdt_get_timeleft(struct watchdog_device *wdt_dev) { - unsigned int time_left; - - spin_lock(&wdt_lock); - time_left = readl(wdt_reg + WDT_VAL) / wdt_tclk; - spin_unlock(&wdt_lock); - - return time_left; + return readl(wdt_reg + WDT_VAL) / wdt_tclk; } static int orion_wdt_set_timeout(struct watchdog_device *wdt_dev,
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