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);
 }