[U-Boot] [PATCH] OMAP3: set L1NEON bit in aux control register

[U-Boot] [PATCH] OMAP3: set L1NEON bit in aux control register

[Mans Rullgard]

This is required to work around ARM erratum 621766, affecting
Cortex-A8 r1p0-3:

  When a sequence of Neon load instructions is intermixed with several
  branches, some of which are mispredicted, it is possible for the
  processor to deadlock due to Neon loads on the speculative path not
  being properly flushed from the Neon load queue.

Signed-off-by: Mans Rullgard <mans@mansr.com>
---
 cpu/arm_cortexa8/omap3/board.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/cpu/arm_cortexa8/omap3/board.c b/cpu/arm_cortexa8/omap3/board.c
index 90809a6..7c2a7ea 100644
--- a/cpu/arm_cortexa8/omap3/board.c
+++ b/cpu/arm_cortexa8/omap3/board.c
@@ -139,6 +139,8 @@ void setup_auxcr()
 	__asm__ __volatile__("mrc p15, 0, r0, c1, c0, 1");
 	/* Enabling ASA */
 	__asm__ __volatile__("orr r0, r0, #0x10");
+	/* Enable L1NEON */
+	__asm__ __volatile__("orr r0, r0, #1<<5");
 	/* SMI instruction to call ROM Code API */
 	__asm__ __volatile__(".word 0xE1600070");
 	__asm__ __volatile__("mov r0, %0":"=r"(i));
-- 
1.6.0.3

[U-Boot] [PATCH] OMAP3: set L1NEON bit in aux control register

[Dirk Behme]

Mans Rullgard wrote:
> This is required to work around ARM erratum 621766, affecting
> Cortex-A8 r1p0-3:
> 
>   When a sequence of Neon load instructions is intermixed with several
>   branches, some of which are mispredicted, it is possible for the
>   processor to deadlock due to Neon loads on the speculative path not
>   being properly flushed from the Neon load queue.
> 
> Signed-off-by: Mans Rullgard <mans@mansr.com>

Acked-by: Dirk Behme <dirk.behme@gmail.com>

---

Jean-Christophe: This is for u-boot-arm/omap3, so please read the 
subject as "[PATCH-OMAP3] OMAP3: ..."

> ---
>  cpu/arm_cortexa8/omap3/board.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
> 
> diff --git a/cpu/arm_cortexa8/omap3/board.c b/cpu/arm_cortexa8/omap3/board.c
> index 90809a6..7c2a7ea 100644
> --- a/cpu/arm_cortexa8/omap3/board.c
> +++ b/cpu/arm_cortexa8/omap3/board.c
> @@ -139,6 +139,8 @@ void setup_auxcr()
>  	__asm__ __volatile__("mrc p15, 0, r0, c1, c0, 1");
>  	/* Enabling ASA */
>  	__asm__ __volatile__("orr r0, r0, #0x10");
> +	/* Enable L1NEON */
> +	__asm__ __volatile__("orr r0, r0, #1<<5");
>  	/* SMI instruction to call ROM Code API */
>  	__asm__ __volatile__(".word 0xE1600070");
>  	__asm__ __volatile__("mov r0, %0":"=r"(i));