[U-Boot] [PATCH] 74xx: use r4 instead of r2 in lock_ram_in_cache and unlock_ram_in_cache

[Kumar Gala]

On Oct 23, 2008, at 8:59 AM, Dave Liu wrote:

> The patch is following the commit  
> 392438406041415fe64ab8748ec5ab5ad01d1cf7
>
> mpc86xx: use r4 instead of r2 in lock_ram_in_cache and  
> unlock_ram_in_cache
>
> This is needed in unlock_ram_in_cache() because it is called from C  
> and
> will corrupt the small data area anchor that is kept in R2.
>
> lock_ram_in_cache() is modified similarly as good coding practice, but
> is not called from C.
>
> Signed-off-by: Nick Spence <nick.spence at freescale.com>
>
> also, the r2 is used as global data pointer.
>
> Signed-off-by: Dave Liu <daveliu at freescale.com>
> ---
> cpu/74xx_7xx/start.S |    8 ++++----
> 1 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/cpu/74xx_7xx/start.S b/cpu/74xx_7xx/start.S
> index 07bbe01..b5484e3 100644
> --- a/cpu/74xx_7xx/start.S
> +++ b/cpu/74xx_7xx/start.S
> @@ -857,9 +857,9 @@ lock_ram_in_cache:
> 	 */
> 	lis	r3, (CONFIG_SYS_INIT_RAM_ADDR & ~31)@h
> 	ori	r3, r3, (CONFIG_SYS_INIT_RAM_ADDR & ~31)@l
> -	li	r2, ((CONFIG_SYS_INIT_RAM_END & ~31) + \
> +	li	r4, ((CONFIG_SYS_INIT_RAM_END & ~31) + \
> 		     (CONFIG_SYS_INIT_RAM_ADDR & 31) + 31) / 32
> -	mtctr	r2
> +	mtctr	r4
> 1:
> 	dcbz	r0, r3
> 	addi	r3, r3, 32
> @@ -878,9 +878,9 @@ unlock_ram_in_cache:
> 	/* invalidate the INIT_RAM section */
> 	lis	r3, (CONFIG_SYS_INIT_RAM_ADDR & ~31)@h
> 	ori	r3, r3, (CONFIG_SYS_INIT_RAM_ADDR & ~31)@l
> -	li	r2, ((CONFIG_SYS_INIT_RAM_END & ~31) + \
> +	li	r4, ((CONFIG_SYS_INIT_RAM_END & ~31) + \
> 		     (CONFIG_SYS_INIT_RAM_ADDR & 31) + 31) / 32
> -	mtctr	r2
> +	mtctr	r4
> 1:	icbi	r0, r3
> 	addi	r3, r3, 32
> 	bdnz	1b

Can we change the 31 to CONFIG_SYS_CACHELINE_SIZE-1

It doesn't matter much for 7xx/74xx/e600 as the cache line size has  
always been 32-bytes, but good to make the code a bit more readable

- k