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

[Liu Dave-R63238]

> From: Kumar Gala [mailto:galak at kernel.crashing.org] 
> 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

Patch welcomed!

Thanks,
Dave