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

The decompressor expects the L2 cache to be disabled. This fixes booting
some kernels, which have CONFIG_ARM_PATCH_PHYS_VIRT enabled.

Signed-off-by: Michael Walle <michael@walle.cc>
Cc: Albert ARIBAUD <albert.u.boot@aribaud.net>
Cc: Prafulla Wadaskar <prafulla@marvell.com>
---
 arch/arm/cpu/arm926ejs/cache.c           |   15 +++++++++++
 arch/arm/cpu/arm926ejs/cpu.c             |    2 +
 arch/arm/cpu/arm926ejs/kirkwood/Makefile |    1 +
 arch/arm/cpu/arm926ejs/kirkwood/cache.c  |   41 ++++++++++++++++++++++++++++++
 4 files changed, 59 insertions(+), 0 deletions(-)
 create mode 100644 arch/arm/cpu/arm926ejs/kirkwood/cache.c

Am Sonntag 18 Dezember 2011, 23:09:51 schrieb Michael Walle:
> The decompressor expects the L2 cache to be disabled. This fixes booting
> some kernels, which have CONFIG_ARM_PATCH_PHYS_VIRT enabled.
You should consider applying this patch to the RC, too. 
CONFIG_ARM_PATCH_PHYS_VIRT is enabled by default since 3.2-rc1.

> The decompressor expects the L2 cache to be disabled. This fixes booting
> some kernels, which have CONFIG_ARM_PATCH_PHYS_VIRT enabled.
> 
> Signed-off-by: Michael Walle <michael@walle.cc>
> Cc: Albert ARIBAUD <albert.u.boot@aribaud.net>
> Cc: Prafulla Wadaskar <prafulla@marvell.com>
> ---
>  arch/arm/cpu/arm926ejs/cache.c           |   15 +++++++++++
>  arch/arm/cpu/arm926ejs/cpu.c             |    2 +
>  arch/arm/cpu/arm926ejs/kirkwood/Makefile |    1 +
>  arch/arm/cpu/arm926ejs/kirkwood/cache.c  |   41
> ++++++++++++++++++++++++++++++ 4 files changed, 59 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 4415642..7a7d0a6 100644
> --- a/arch/arm/cpu/arm926ejs/cache.c
> +++ b/arch/arm/cpu/arm926ejs/cache.c
> @@ -73,3 +73,18 @@ void  flush_cache(unsigned long start, unsigned long
> size) {
>  }
>  #endif /* #ifndef CONFIG_SYS_DCACHE_OFF */
> +
> +/*
> + * Stub implementations for l2 cache operations
> + */
> +void __l2_cache_enable(void)
> +{
> +}
> +void l2_cache_enable(void)
> +        __attribute__((weak, alias("__l2_cache_enable")));
> +
> +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..84207f7
> --- /dev/null
> +++ b/arch/arm/cpu/arm926ejs/kirkwood/cache.c
> @@ -0,0 +1,41 @@
> +/*
> + * Copyright (c) 2011 Michael Walle
> + * Michael Walle <michael@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>
> +
> +void l2_cache_enable()
> +{
> +	u32 ctrl;
> +
> +	ctrl = readfr_extra_feature_reg();
> +	ctrl |= 1 << 22;	/* enable l2 cache */
> +	writefr_extra_feature_reg(ctrl);
> +}
> +
> +void l2_cache_disable()
> +{
> +	u32 ctrl;
> +
> +	ctrl = readfr_extra_feature_reg();
> +	ctrl &= ~(1 << 22);	/* disable l2 cache */
> +	writefr_extra_feature_reg(ctrl);
> +}

Please use #define <name> to define the magic value above (1 << 22) and then use 
it.

M

Am Montag 19 Dezember 2011, 00:04:18 schrieb Marek Vasut:
[..snip..]
> Please use #define <name> to define the magic value above (1 << 22) and
> then use it.
> 
> M

The bit was taken from arch/arm/cpu/arm926ejs/kirkwood/cpu.c. Unfortunately 
there is no documentation publicly available, so i can only guess names.

FEROCEON_EXTRA_FEATURE_L2C_EN ?

Even the linux kernel has no proper macro names :(

Hi Michael,

Le 19/12/2011 00:21, Michael Walle a écrit :
> Am Montag 19 Dezember 2011, 00:04:18 schrieb Marek Vasut:
> [..snip..]
>> Please use #define<name>  to define the magic value above (1<<  22) and
>> then use it.
>>
>> M
>
> The bit was taken from arch/arm/cpu/arm926ejs/kirkwood/cpu.c. Unfortunately
> there is no documentation publicly available, so i can only guess names.
>
> FEROCEON_EXTRA_FEATURE_L2C_EN ?

Works for me.

> Even the linux kernel has no proper macro names :(

Time we told them to have one, then. :)

I assume the patch was tested against a 3.2-rc1 kernel and also a 
pre-3.2-rc1 kernel to avoid regression?

Amicalement,

Am Dienstag 20 Dezember 2011, 08:04:23 schrieb Albert ARIBAUD:
> I assume the patch was tested against a 3.2-rc1 kernel and also a
> pre-3.2-rc1 kernel to avoid regression?
Tested with 3.0, 3.1 and 3.2-rc both with CONFIG_ARM_PATCH_PHYS_VIRT enabled 
and disabled.