From b5bd09820c79dc92b3e5fb5be4b47ce22c731443 Mon Sep 17 00:00:00 2001 From: Simon Glass Date: Thu, 5 May 2016 07:28:06 -0600 Subject: [PATCH] arm: Allow skipping of low-level init with I-cache on MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Tested-on: smartweb, corvus, taurus, axm Tested-by: Heiko Schocher Reviewed-by: Joe Hershberger Signed-off-by: Simon Glass Reviewed-by: Andreas Bießmann --- 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 1d0b946977..03bed18059 100644 --- a/README +++ b/README @@ -4824,6 +4824,11 @@ 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 + 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 3ebdfddc80..2f8fd6acc2 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 69cabebed9..3ada6d026f 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 f05113da9d..959d1ed86d 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 214cd8cbd9..51053c32dc 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 b18094447b..691e5d3fe1 100644 --- a/arch/arm/cpu/armv7/start.S +++ b/arch/arm/cpu/armv7/start.S @@ -66,7 +66,9 @@ 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 408b70dbc1..f5318c90d1 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