ARM: imx: move clk_prepare() out from mxc_restart()

It's inappropriate to call clk_prepare() in mxc_restart(), because the
restart routine could be called in atomic context.  Move clk_get() and
clk_prepare() into mxc_arch_reset_init() and only have the atomic part
clk_enable() be called in mxc_restart().

As a result, mxc_arch_reset_init() needs to be called after clk gets
initialized.

While there, it also changes printk(KERN_ERR ...) to pr_err() and adds
__init annotation for mxc_arch_reset_init().

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

1 files changed, 17 insertions, 10 deletions

diff --git a/arch/arm/mach-imx/system.c b/arch/arm/mach-imx/system.c
index 695e0d73bf85..02cf449094f1 100644
--- a/arch/arm/mach-imx/system.c
+++ b/arch/arm/mach-imx/system.c
@@ -30,6 +30,7 @@
 #include "hardware.h"
 
 static void __iomem *wdog_base;
+static struct clk *wdog_clk;
 
 /*
  * Reset the system. It is called by machine_restart().
@@ -38,16 +39,13 @@ void mxc_restart(char mode, const char *cmd)
 {
 	unsigned int wcr_enable;
 
-	if (cpu_is_mx1()) {
-		wcr_enable = (1 << 0);
-	} else {
-		struct clk *clk;
+	if (wdog_clk)
+		clk_enable(wdog_clk);
 
-		clk = clk_get_sys("imx2-wdt.0", NULL);
-		if (!IS_ERR(clk))
-			clk_prepare_enable(clk);
+	if (cpu_is_mx1())
+		wcr_enable = (1 << 0);
+	else
 		wcr_enable = (1 << 2);
-	}
 
 	/* Assert SRS signal */
 	__raw_writew(wcr_enable, wdog_base);
@@ -55,7 +53,7 @@ void mxc_restart(char mode, const char *cmd)
 	/* wait for reset to assert... */
 	mdelay(500);
 
-	printk(KERN_ERR "Watchdog reset failed to assert reset\n");
+	pr_err("%s: Watchdog reset failed to assert reset\n", __func__);
 
 	/* delay to allow the serial port to show the message */
 	mdelay(50);
@@ -64,7 +62,16 @@ void mxc_restart(char mode, const char *cmd)
 	soft_restart(0);
 }
 
-void mxc_arch_reset_init(void __iomem *base)
+void __init mxc_arch_reset_init(void __iomem *base)
 {
 	wdog_base = base;
+
+	wdog_clk = clk_get_sys("imx2-wdt.0", NULL);
+	if (IS_ERR(wdog_clk)) {
+		pr_warn("%s: failed to get wdog clock\n", __func__);
+		wdog_clk = NULL;
+		return;
+	}
+
+	clk_prepare(wdog_clk);
 }