ARM: OMAP: Avoid sleeping during arch_reset

If we call clk_get() from arch_reset we get ugly messages before
reboot.
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/clock.c

@@ -37,6 +37,8 @@
 
 static struct prcm_config *curr_prcm_set;
 static u32 curr_perf_level = PRCM_FULL_SPEED;
+static struct clk *vclk;
+static struct clk *sclk;
 
 /*-------------------------------------------------------------------------
  * Omap2 specific clock functions
@@ -985,6 +987,20 @@ static void __init omap2_get_crystal_rate(struct clk *osc, struct clk *sys)
 	sys->rate = sclk;
 }
 
+/*
+ * Set clocks for bypass mode for reboot to work.
+ */
+void omap2_clk_prepare_for_reboot(void)
+{
+	u32 rate;
+
+	if (vclk == NULL || sclk == NULL)
+		return;
+
+	rate = clk_get_rate(sclk);
+	clk_set_rate(vclk, rate);
+}
+
 #ifdef CONFIG_OMAP_RESET_CLOCKS
 static void __init omap2_disable_unused_clocks(void)
 {
@@ -1081,5 +1097,9 @@ int __init omap2_clk_init(void)
 	if (cpu_is_omap2430())
 		clk_enable(&sdrc_ick);
 
+	/* Avoid sleeping sleeping during omap2_clk_prepare_for_reboot() */
+	vclk = clk_get(NULL, "virt_prcm_set");
+	sclk = clk_get(NULL, "sys_ck");
+
 	return 0;
 }

arch/arm/mach-omap2/prcm.c

@@ -20,6 +20,8 @@
 
 #include "prcm-regs.h"
 
+extern void omap2_clk_prepare_for_reboot(void);
+
 u32 omap_prcm_get_reset_sources(void)
 {
 	return RM_RSTST_WKUP & 0x7f;
@@ -29,12 +31,6 @@ EXPORT_SYMBOL(omap_prcm_get_reset_sources);
 /* Resets clock rates and reboots the system. Only called from system.h */
 void omap_prcm_arch_reset(char mode)
 {
-	u32 rate;
-	struct clk *vclk, *sclk;
-
-	vclk = clk_get(NULL, "virt_prcm_set");
-	sclk = clk_get(NULL, "sys_ck");
-	rate = clk_get_rate(sclk);
-	clk_set_rate(vclk, rate);	/* go to bypass for OMAP limitation */
+	omap2_clk_prepare_for_reboot();
 	RM_RSTCTRL_WKUP |= 2;
 }