[U-Boot] [PATCH v4] arm, arm-kirkwood: disable l2c before linux boot

[Ian Campbell]

On Wed, 2012-02-01 at 19:24 +0100, Michael Walle wrote:
> The decompressor expects the L2 cache to be disabled. This fixes booting
> some kernels, which have CONFIG_ARM_PATCH_PHYS_VIRT enabled.

I applied this locally and was able to boot a 3.2 Linux kernel on my
dreamplug where before I was having random hangs which went away when I
hacked the kernel to disable CONFIG_ARM_PATCH_PHYS_VIRT (ick). So:

Tested-by: Ian Campbell <ijc at hellion.org.uk>

Thanks Michael!

Ian.

> 
> Signed-off-by: Michael Walle <michael at walle.cc>
> Acked-by: Prafulla Wadaskar <prafulla at marvell.com>
> Cc: Albert ARIBAUD <albert.u.boot at aribaud.net>
> Cc: Prafulla Wadaskar <prafulla at marvell.com>
> Cc: Wolfgang Denk <wd at denx.de>
> ---
> v4:
>   update copyright year of arch/arm/cpu/arm926ejs/kirkwood/cache.c
>   add acked by prafulla
> 
> v3:
>   remove unused enable function
> 
> v2:
>   replace magic number with macro
> 
>  arch/arm/cpu/arm926ejs/cache.c           |    9 ++++++++
>  arch/arm/cpu/arm926ejs/cpu.c             |    2 +
>  arch/arm/cpu/arm926ejs/kirkwood/Makefile |    1 +
>  arch/arm/cpu/arm926ejs/kirkwood/cache.c  |   34 ++++++++++++++++++++++++++++++
>  4 files changed, 46 insertions(+), 0 deletions(-)
>  create mode 100644 arch/arm/cpu/arm926ejs/kirkwood/cache.c
> 
> diff --git a/arch/arm/cpu/arm926ejs/cache.c b/arch/arm/cpu/arm926ejs/cache.c
> index ee90ab7..504f604 100644
> --- a/arch/arm/cpu/arm926ejs/cache.c
> +++ b/arch/arm/cpu/arm926ejs/cache.c
> @@ -68,3 +68,12 @@ void  flush_cache(unsigned long start, unsigned long size)
>  {
>  }
>  #endif /* #ifndef CONFIG_SYS_DCACHE_OFF */
> +
> +/*
> + * Stub implementations for l2 cache operations
> + */
> +void __l2_cache_disable(void)
> +{
> +}
> +void l2_cache_disable(void)
> +        __attribute__((weak, alias("__l2_cache_disable")));
> diff --git a/arch/arm/cpu/arm926ejs/cpu.c b/arch/arm/cpu/arm926ejs/cpu.c
> index 5c902df..626384c 100644
> --- a/arch/arm/cpu/arm926ejs/cpu.c
> +++ b/arch/arm/cpu/arm926ejs/cpu.c
> @@ -50,6 +50,8 @@ int cleanup_before_linux (void)
>  	/* turn off I/D-cache */
>  	icache_disable();
>  	dcache_disable();
> +	l2_cache_disable();
> +
>  	/* flush I/D-cache */
>  	cache_flush();
>  
> diff --git a/arch/arm/cpu/arm926ejs/kirkwood/Makefile b/arch/arm/cpu/arm926ejs/kirkwood/Makefile
> index 0754297..777006c 100644
> --- a/arch/arm/cpu/arm926ejs/kirkwood/Makefile
> +++ b/arch/arm/cpu/arm926ejs/kirkwood/Makefile
> @@ -30,6 +30,7 @@ COBJS-y	= cpu.o
>  COBJS-y	+= dram.o
>  COBJS-y	+= mpp.o
>  COBJS-y	+= timer.o
> +COBJS-y	+= cache.o
>  
>  SRCS	:= $(SOBJS:.o=.S) $(COBJS-y:.o=.c)
>  OBJS	:= $(addprefix $(obj),$(SOBJS) $(COBJS-y))
> diff --git a/arch/arm/cpu/arm926ejs/kirkwood/cache.c b/arch/arm/cpu/arm926ejs/kirkwood/cache.c
> new file mode 100644
> index 0000000..645d962
> --- /dev/null
> +++ b/arch/arm/cpu/arm926ejs/kirkwood/cache.c
> @@ -0,0 +1,34 @@
> +/*
> + * Copyright (c) 2012 Michael Walle
> + * Michael Walle <michael at walle.cc>
> + *
> + * See file CREDITS for list of people who contributed to this
> + * project.
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc.
> + */
> +#include <common.h>
> +#include <asm/arch/cpu.h>
> +
> +#define FEROCEON_EXTRA_FEATURE_L2C_EN (1<<22)
> +
> +void l2_cache_disable()
> +{
> +	u32 ctrl;
> +
> +	ctrl = readfr_extra_feature_reg();
> +	ctrl &= ~FEROCEON_EXTRA_FEATURE_L2C_EN;
> +	writefr_extra_feature_reg(ctrl);
> +}

-- 
Ian Campbell


Marriage is a lot like the army, everyone complains, but you'd be
surprised at the large number that re-enlist.
		-- James Garner