Hi Simon,
On 05.05.16 15:28, Simon Glass wrote:
At present CONFIG_SKIP_LOWLEVEL_INIT prevents U-Boot from calling lowlevel_init(). This means that the instruction cache is not enabled and the board runs very slowly.
What is really needed in many cases is to skip the call to lowlevel_init() but still perform CP15 init. Add an option to handle this.
Reviewed-by: Heiko Schocher hs@denx.de Tested-on: smartweb, corvus, taurus, axm Tested-by: Heiko Schocher hs@denx.de Reviewed-by: Joe Hershberger joe.hershberger@ni.com Signed-off-by: Simon Glass sjg@chromium.org
Changes in v2: None
README | 5 +++++ arch/arm/cpu/arm1136/start.S | 2 ++ arch/arm/cpu/arm920t/start.S | 3 ++- arch/arm/cpu/arm926ejs/start.S | 2 ++ arch/arm/cpu/arm946es/start.S | 2 ++ arch/arm/cpu/armv7/start.S | 5 ++++- arch/arm/cpu/sa1100/start.S | 2 ++ 7 files changed, 19 insertions(+), 2 deletions(-)
diff --git a/README b/README index 88ff837..9ab07b5 100644 --- a/README +++ b/README @@ -4829,6 +4829,11 @@ Low Level (hardware related) configuration options: other boot loader or by a debugger which performs these initializations itself.
+- CONFIG_SKIP_LOWLEVEL_INIT_ONLY
[ARM926EJ-S only] This allows just the call to lowlevel_init()to be skipped. The normal CPU15 init (such as enabling the
CPU15 -> CP15
instruction cache) is still performed.
- CONFIG_SPL_BUILD Modifies the behaviour of start.S when compiling a loader that is executed before the actual U-Boot. E.g. when
diff --git a/arch/arm/cpu/arm1136/start.S b/arch/arm/cpu/arm1136/start.S index 3ebdfdd..2f8fd6a 100644 --- a/arch/arm/cpu/arm1136/start.S +++ b/arch/arm/cpu/arm1136/start.S @@ -82,6 +82,7 @@ cpu_init_crit: orr r0, r0, #0x00001000 @ set bit 12 (I) I-Cache mcr p15, 0, r0, c1, c0, 0
+#ifndef CONFIG_SKIP_LOWLEVEL_INIT_ONLY /* * Jump to board specific initialization... The Mask ROM will have already initialized * basic memory. Go here to bump up clock rate and handle wake up conditions. @@ -89,5 +90,6 @@ cpu_init_crit: mov ip, lr /* persevere link reg across call */ bl lowlevel_init /* go setup pll,mux,memory */ mov lr, ip /* restore link */ +#endif mov pc, lr /* back to my caller */ #endif /* CONFIG_SKIP_LOWLEVEL_INIT */ diff --git a/arch/arm/cpu/arm920t/start.S b/arch/arm/cpu/arm920t/start.S index 69cabeb..3ada6d0 100644 --- a/arch/arm/cpu/arm920t/start.S +++ b/arch/arm/cpu/arm920t/start.S @@ -135,6 +135,7 @@ cpu_init_crit: orr r0, r0, #0x00001000 @ set bit 12 (I) I-Cache mcr p15, 0, r0, c1, c0, 0
+#ifndef CONFIG_SKIP_LOWLEVEL_INIT_ONLY /* * before relocating, we have to setup RAM timing * because memory timing is board-dependend, you will @@ -143,7 +144,7 @@ cpu_init_crit: mov ip, lr
bl lowlevel_init
- mov lr, ip
+#endif mov pc, lr #endif /* CONFIG_SKIP_LOWLEVEL_INIT */ diff --git a/arch/arm/cpu/arm926ejs/start.S b/arch/arm/cpu/arm926ejs/start.S index f05113d..959d1ed 100644 --- a/arch/arm/cpu/arm926ejs/start.S +++ b/arch/arm/cpu/arm926ejs/start.S @@ -101,11 +101,13 @@ flush_dcache: #endif mcr p15, 0, r0, c1, c0, 0
+#ifndef CONFIG_SKIP_LOWLEVEL_INIT_ONLY /* * Go setup Memory and board specific bits prior to relocation. */ mov ip, lr /* perserve link reg across call */ bl lowlevel_init /* go setup pll,mux,memory */ mov lr, ip /* restore link */ +#endif mov pc, lr /* back to my caller */ #endif /* CONFIG_SKIP_LOWLEVEL_INIT */ diff --git a/arch/arm/cpu/arm946es/start.S b/arch/arm/cpu/arm946es/start.S index 214cd8c..51053c3 100644 --- a/arch/arm/cpu/arm946es/start.S +++ b/arch/arm/cpu/arm946es/start.S @@ -90,11 +90,13 @@ cpu_init_crit: orr r0, r0, #0x00001000 /* set bit 12 (I) I-Cache */ mcr p15, 0, r0, c1, c0, 0
+#ifndef CONFIG_SKIP_LOWLEVEL_INIT_ONLY /* * Go setup Memory and board specific bits prior to relocation. */ mov ip, lr /* perserve link reg across call */ bl lowlevel_init /* go setup memory */ mov lr, ip /* restore link */ +#endif mov pc, lr /* back to my caller */ #endif diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S index b180944..691e5d3 100644 --- a/arch/arm/cpu/armv7/start.S +++ b/arch/arm/cpu/armv7/start.S @@ -66,8 +66,10 @@ save_boot_params_ret: /* the mask ROM code should have PLL and others stable */ #ifndef CONFIG_SKIP_LOWLEVEL_INIT bl cpu_init_cp15 +#ifndef CONFIG_SKIP_LOWLEVEL_INIT_ONLY bl cpu_init_crit #endif +#endif
bl _main
@@ -250,7 +252,8 @@ skip_errata_621766: mov pc, r5 @ back to my caller ENDPROC(cpu_init_cp15)
-#ifndef CONFIG_SKIP_LOWLEVEL_INIT +#if !defined(CONFIG_SKIP_LOWLEVEL_INIT) && \
- !defined(CONFIG_SKIP_LOWLEVEL_INIT_ONLY)
/*************************************************************************
- CPU_init_critical registers
diff --git a/arch/arm/cpu/sa1100/start.S b/arch/arm/cpu/sa1100/start.S index 408b70d..f5318c9 100644 --- a/arch/arm/cpu/sa1100/start.S +++ b/arch/arm/cpu/sa1100/start.S @@ -96,6 +96,7 @@ cpu_init_crit: ldr r1, cpuspeed str r1, [r0, #PPCR]
+#ifndef CONFIG_SKIP_LOWLEVEL_INIT_ONLY /* * before relocating, we have to setup RAM timing * because memory timing is board-dependend, you will @@ -104,6 +105,7 @@ cpu_init_crit: mov ip, lr bl lowlevel_init mov lr, ip +#endif
/* * disable MMU stuff and enable I-cache
Reviewed-by: Andreas Bießmann andreas@biessmann.org