ARM: OMAP2: Make sure peripherals can be accessed after clk_enable
Some peripherals seem to need additional delay until they
can actually be accessed after enabling their FCLK and ICLK.
Signed-off-by: Juha Yrjola <juha.yrjola@solidboot.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
diff --git a/arch/arm/mach-omap2/clock.c b/arch/arm/mach-omap2/clock.c
index eee273b..26ac49e 100644
--- a/arch/arm/mach-omap2/clock.c
+++ b/arch/arm/mach-omap2/clock.c
@@ -32,6 +32,8 @@
#include "memory.h"
#include "clock.h"
+#undef DEBUG
+
//#define DOWN_VARIABLE_DPLL 1 /* Experimental */
static struct prcm_config *curr_prcm_set;
@@ -114,11 +116,53 @@
while (!(CM_IDLEST_CKGEN & cval)) { /* Wait for lock */
++i;
udelay(1);
- if (i == 100000)
+ if (i == 100000) {
+ printk(KERN_ERR "Clock %s didn't lock\n", clk->name);
break;
+ }
}
}
+static void omap2_clk_wait_ready(struct clk *clk)
+{
+ unsigned long reg, other_reg, st_reg;
+ u32 bit;
+ int i;
+
+ reg = (unsigned long) clk->enable_reg;
+ if (reg == (unsigned long) &CM_FCLKEN1_CORE ||
+ reg == (unsigned long) &CM_FCLKEN2_CORE)
+ other_reg = (reg & ~0xf0) | 0x10;
+ else if (reg == (unsigned long) &CM_ICLKEN1_CORE ||
+ reg == (unsigned long) &CM_ICLKEN2_CORE)
+ other_reg = (reg & ~0xf0) | 0x00;
+ else
+ return;
+
+ /* No check for DSS or cam clocks */
+ if ((reg & 0x0f) == 0) {
+ if (clk->enable_bit <= 1 || clk->enable_bit == 31)
+ return;
+ }
+
+ /* Check if both functional and interface clocks
+ * are running. */
+ bit = 1 << clk->enable_bit;
+ if (!(__raw_readl(other_reg) & bit))
+ return;
+ st_reg = (other_reg & ~0xf0) | 0x20;
+ i = 0;
+ while (!(__raw_readl(st_reg) & bit)) {
+ i++;
+ if (i == 100000) {
+ printk(KERN_ERR "Timeout enabling clock %s\n", clk->name);
+ break;
+ }
+ }
+ if (i)
+ pr_debug("Clock %s stable after %d loops\n", clk->name, i);
+}
+
/* Enables clock without considering parent dependencies or use count
* REVISIT: Maybe change this to use clk->enable like on omap1?
*/
@@ -150,6 +194,8 @@
__raw_writel(regval32, clk->enable_reg);
wmb();
+ omap2_clk_wait_ready(clk);
+
return 0;
}