[U-Boot] omap3: Is lowlevel_init() ever called?

[Premi, Sanjeev]

Hi all,

I have been trying to debug 'strange' clock settings in the omap3evm; that would
surface quite infrequently. However, today I was able to get them regularly.

Symptom: the MPU clock is set at 381MHz instead of expected 500MHz.

Tracing back from prcm_init() to s_init() to lowlevel_init() and cpu_init_crit()
I feel that lowlevel_init() is being skipped at together.

In the patch below, I am updating a flag on very beginning of s_init() and later
printing in print_cpuinfo(). To exclude any other (possible) foul-play by stray
pointer, I initialized this flag to 11 and expect it to be 55 after s_init() is
called. But the value remains 11 - when printed in print_cpuinfo().

Also, CONFIG_SKIP_LOWLEVEL_INIT is not defined in omap3_evm_config.

Though I am at 2009.08, I did not see any differences in start.S that could have
an apparent effect.

Am I missing something completely?

Best regards,
Sanjeev



diff --git a/cpu/arm_cortexa8/omap3/board.c b/cpu/arm_cortexa8/omap3/board.c
index 939ed6c..5dfd8f3 100644
--- a/cpu/arm_cortexa8/omap3/board.c
+++ b/cpu/arm_cortexa8/omap3/board.c
@@ -42,6 +42,8 @@ extern omap3_sysinfo sysinfo;
 
 extern u32 is_mem_sdr(void);
 
+int s_init_flag=11;
+
 /******************************************************************************
  * Routine: delay
  * Description: spinning delay to use before udelay works
@@ -193,6 +195,8 @@ void s_init(void)
 {
 	int in_sdram = is_running_in_sdram();
 
+	s_init_flag=55;
+
 	watchdog_init();
 
 	try_unlock_memory();
diff --git a/cpu/arm_cortexa8/omap3/lowlevel_init.S b/cpu/arm_cortexa8/omap3/lowlevel_init.S
index 73063ec..d83dd53 100644
--- a/cpu/arm_cortexa8/omap3/lowlevel_init.S
+++ b/cpu/arm_cortexa8/omap3/lowlevel_init.S
@@ -174,7 +174,11 @@ lowlevel_init:
 	ldr	sp, SRAM_STACK
 	str	ip, [sp]	/* stash old link register */
 	mov	ip, lr		/* save link reg across call */
+	nop
+	nop
 	bl	s_init		/* go setup pll, mux, memory */
+	nop
+	nop
 	ldr	ip, [sp]	/* restore save ip */
 	mov	lr, ip		/* restore link reg */
 
diff --git a/cpu/arm_cortexa8/omap3/sys_info.c b/cpu/arm_cortexa8/omap3/sys_info.c
index 2fb6c10..2f29032 100644
--- a/cpu/arm_cortexa8/omap3/sys_info.c
+++ b/cpu/arm_cortexa8/omap3/sys_info.c
@@ -31,6 +31,8 @@
 #include <asm/arch/sys_proto.h>
 #include <i2c.h>
 
+extern int s_init_flag;
+
 extern omap3_sysinfo sysinfo;
 static struct sdrc *sdrc_base = (struct sdrc *)OMAP34XX_SDRC_BASE;
 static struct ctrl *ctrl_base = (struct ctrl *)OMAP34XX_CTRL_BASE;
@@ -414,6 +416,8 @@ int print_cpuinfo (void)
 			cpu_s, sec_s, rev_s[get_cpu_rev()],
 			(cpu_family == CPU_AM35XX) ? "" : " CPU-OPP2");
 
+	printf ("s_init_flag = %d\n", s_init_flag);
+	
 	return 0;
 }
 #endif	/* CONFIG_DISPLAY_CPUINFO */

======================================

U-Boot 2009.08-00047-gd5ef5fe-dirty (Nov 30 2009 - 23:15:59)

OMAP3430/3530-GP ES3.1, CPU-OPP2 L3-165MHz
s_init_flag = 11
OMAP3 EVM board + LPDDR/NAND
DRAM:  128 MB
NAND:  256 MiB
In:    serial
Out:   serial
Err:   serial
Die ID #609200040000000004032d460c01201a
Net:   smc911x-0
Hit any key to stop autoboot:  0
OMAP3_EVM #
OMAP3_EVM #
OMAP3_EVM #