[U-Boot] [PATCH V2] arm: armv7: omap3: Fix restore sequence in lowlevel_init

[U-Boot] [PATCH V2] arm: armv7: omap3: Fix restore sequence in lowlevel_init

[Albert ARIBAUD]

The restore sequence in lowlevel_init was in the wrong order,
causing lr to lose its original value and be set equal to ip
instead. Also, its use of the stack clashes with that of
s_init, so move the s_init call after the restore and turn
it  into a tail-optimized branch.

Signed-off-by: Albert ARIBAUD <albert.u.boot@aribaud.net>
---
V2: move s_init call after restore and tail-optimize it into a branch
V1: fix order of restores

 arch/arm/cpu/armv7/omap3/lowlevel_init.S |    9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/arch/arm/cpu/armv7/omap3/lowlevel_init.S b/arch/arm/cpu/armv7/omap3/lowlevel_init.S
index ebf69fa..eacfef8 100644
--- a/arch/arm/cpu/armv7/omap3/lowlevel_init.S
+++ b/arch/arm/cpu/armv7/omap3/lowlevel_init.S
@@ -214,7 +214,7 @@ pll_div_val5:
 
 ENTRY(lowlevel_init)
 	ldr	sp, SRAM_STACK
-	str	ip, [sp]	/* stash old link register */
+	str	ip, [sp]	/* stash ip register */
 	mov	ip, lr		/* save link reg across call */
 #if !defined(CONFIG_SYS_NAND_BOOT) && !defined(CONFIG_SYS_ONENAND_BOOT)
 /*
@@ -224,12 +224,11 @@ ENTRY(lowlevel_init)
 	ldr	r1, =SRAM_CLK_CODE
 	bl	cpy_clk_code
 #endif /* NAND Boot */
-	bl	s_init		/* go setup pll, mux, memory */
-	ldr	ip, [sp]	/* restore save ip */
 	mov	lr, ip		/* restore link reg */
+	ldr	ip, [sp]	/* restore save ip */
+	/* tail-call s_init to setup pll, mux, memory */
+	b	s_init
 
-	/* back to arch calling code */
-	mov	pc, lr
 ENDPROC(lowlevel_init)
 
 	/* the literal pools origin */
-- 
1.7.9.5

[U-Boot] [PATCH V2] arm: armv7: omap3: Fix restore sequence in lowlevel_init

[Jeroen Hofstee]

On 10/07/2012 09:24 PM, Albert ARIBAUD wrote:
> The restore sequence in lowlevel_init was in the wrong order,
> causing lr to lose its original value and be set equal to ip
> instead. Also, its use of the stack clashes with that of
> s_init, so move the s_init call after the restore and turn
> it  into a tail-optimized branch.
>
> Signed-off-by: Albert ARIBAUD <albert.u.boot@aribaud.net>
> ---
> V2: move s_init call after restore and tail-optimize it into a branch
> V1: fix order of restores
>
>   arch/arm/cpu/armv7/omap3/lowlevel_init.S |    9 ++++-----
>   1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/arch/arm/cpu/armv7/omap3/lowlevel_init.S b/arch/arm/cpu/armv7/omap3/lowlevel_init.S
> index ebf69fa..eacfef8 100644
> --- a/arch/arm/cpu/armv7/omap3/lowlevel_init.S
> +++ b/arch/arm/cpu/armv7/omap3/lowlevel_init.S
> @@ -214,7 +214,7 @@ pll_div_val5:
>   
>   ENTRY(lowlevel_init)
>   	ldr	sp, SRAM_STACK
> -	str	ip, [sp]	/* stash old link register */
> +	str	ip, [sp]	/* stash ip register */
>   	mov	ip, lr		/* save link reg across call */
>   #if !defined(CONFIG_SYS_NAND_BOOT) && !defined(CONFIG_SYS_ONENAND_BOOT)
>   /*
> @@ -224,12 +224,11 @@ ENTRY(lowlevel_init)
>   	ldr	r1, =SRAM_CLK_CODE
>   	bl	cpy_clk_code
>   #endif /* NAND Boot */
> -	bl	s_init		/* go setup pll, mux, memory */
> -	ldr	ip, [sp]	/* restore save ip */
>   	mov	lr, ip		/* restore link reg */
> +	ldr	ip, [sp]	/* restore save ip */
> +	/* tail-call s_init to setup pll, mux, memory */
> +	b	s_init
>   
> -	/* back to arch calling code */
> -	mov	pc, lr
>   ENDPROC(lowlevel_init)
>   
>   	/* the literal pools origin */
Tested-by: Jeroen Hofstee <jeroen@myspectrum.nl>

on a tam3517 SOM (am3517 mcu) derived board.

Regards,
Jeroen

[U-Boot] [U-Boot, V2] arm: armv7: omap3: Fix restore sequence in lowlevel_init

[Tom Rini]

On Sun, Oct 07, 2012 at 09:24:10AM -0000, Albert ARIBAUD wrote:

> The restore sequence in lowlevel_init was in the wrong order,
> causing lr to lose its original value and be set equal to ip
> instead. Also, its use of the stack clashes with that of
> s_init, so move the s_init call after the restore and turn
> it  into a tail-optimized branch.
> 
> Signed-off-by: Albert ARIBAUD <albert.u.boot@aribaud.net>
> Tested-by: Jeroen Hofstee <jeroen@myspectrum.nl>

Applied to u-boot/master, thanks!

-- 
Tom
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