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authorSimon Glass <sjg@chromium.org>2011-11-05 03:56:51 +0000
committerAlbert ARIBAUD <albert.u.boot@aribaud.net>2011-12-09 17:30:09 +0100
commit80433c9ac6fd3bd0fe1707a04d9668db4aba1dde (patch)
treebb02432e43369953e07cd26b1c29beb8c32f3828 /arch/arm
parent210576fc5e5d323c8039f95c7b5b2c7512a550e4 (diff)
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arm: Move CP15 init out of cpu_init_crit()
Some SOCs have do not start up with their 'main' CPU. The first U-Boot code may then be executed with a CPU which does not have a CP15, or not a useful one. Here we split the initialization of CP15 into a separate call, which can be performed later if required. Once the main CPU is running, you should call cpu_init_cp15() to perform this init as early as possible. Existing ARMv7 boards which define CONFIG_SKIP_LOWLEVEL_INIT should not need to change, this CP15 init is still skipped in that case. The only impact for these boards is that the cpu_init_cp15() will be available even if it is never used on these boards. Signed-off-by: Simon Glass <sjg@chromium.org> Signed-off-by: Tom Warren <twarren@nvidia.com>
Diffstat (limited to 'arch/arm')
-rw-r--r--arch/arm/cpu/armv7/start.S24
-rw-r--r--arch/arm/include/asm/u-boot-arm.h3
2 files changed, 21 insertions, 6 deletions
diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S
index d23dc9d..b05be6c 100644
--- a/arch/arm/cpu/armv7/start.S
+++ b/arch/arm/cpu/armv7/start.S
@@ -162,6 +162,7 @@ reset:
/* the mask ROM code should have PLL and others stable */
#ifndef CONFIG_SKIP_LOWLEVEL_INIT
+ bl cpu_init_cp15
bl cpu_init_crit
#endif
@@ -299,17 +300,16 @@ jump_2_ram:
_board_init_r_ofs:
.word board_init_r - _start
-
-#ifndef CONFIG_SKIP_LOWLEVEL_INIT
/*************************************************************************
*
- * CPU_init_critical registers
+ * cpu_init_cp15
*
- * setup important registers
- * setup memory timing
+ * Setup CP15 registers (cache, MMU, TLBs). The I-cache is turned on unless
+ * CONFIG_SYS_ICACHE_OFF is defined.
*
*************************************************************************/
-cpu_init_crit:
+.globl cpu_init_cp15
+cpu_init_cp15:
/*
* Invalidate L1 I/D
*/
@@ -334,7 +334,19 @@ cpu_init_crit:
orr r0, r0, #0x00001000 @ set bit 12 (I) I-cache
#endif
mcr p15, 0, r0, c1, c0, 0
+ mov pc, lr @ back to my caller
+
+#ifndef CONFIG_SKIP_LOWLEVEL_INIT
+/*************************************************************************
+ *
+ * CPU_init_critical registers
+ *
+ * setup important registers
+ * setup memory timing
+ *
+ *************************************************************************/
+cpu_init_crit:
/*
* Jump to board specific initialization...
* The Mask ROM will have already initialized
diff --git a/arch/arm/include/asm/u-boot-arm.h b/arch/arm/include/asm/u-boot-arm.h
index d3308f7..4ca75f9 100644
--- a/arch/arm/include/asm/u-boot-arm.h
+++ b/arch/arm/include/asm/u-boot-arm.h
@@ -46,6 +46,9 @@ extern ulong IRQ_STACK_START_IN; /* 8 bytes in IRQ stack */
int cpu_init(void);
int cleanup_before_linux(void);
+/* Set up ARMv7 MMU, caches and TLBs */
+void cpu_init_cp15(void);
+
/* cpu/.../arch/cpu.c */
int arch_cpu_init(void);
int arch_misc_init(void);