From mboxrd@z Thu Jan  1 00:00:00 1970
From: Brad Parker <brad@heeltoe.com>
Date: Fri, 13 Aug 2010 19:51:43 -0400
Subject: [U-Boot] UNS: [Nios2-dev] [PATCH] nios2: fix out of reach case
	for do_reset
In-Reply-To: <1281667205-23282-1-git-send-email-thomas@wytron.com.tw>
	(sfid-20100812_224039_277713_FED0353C)
References: <1281667205-23282-1-git-send-email-thomas@wytron.com.tw>
	(sfid-20100812_224039_277713_FED0353C)
Message-ID: <4C65DA8F.5000301@heeltoe.com>
List-Id: <u-boot.lists.denx.de>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
To: u-boot@lists.denx.de

As a comment, that patch looks pretty ugly.  I might suggest an inline 
function (called "callr" or "nios2_callr") which
encapsulates the __asm__.   That would make the code much easier to read.

You could put the inline function in one of the asm headers.

-brad

Thomas Chou wrote:
> The "Nios II Processor Reference Handbook" said,
> "call can transfer execution anywhere within the 256 MByte range
> determined by PC31..28. The Nios II GNU linker does not automatically
> handle cases in which the address is out of this range."
>
> So we have to use registered "callr" instruction to do the job.
>
> Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
> ---
>  arch/nios2/cpu/cpu.c |   14 ++++++++------
>  1 files changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/arch/nios2/cpu/cpu.c b/arch/nios2/cpu/cpu.c
> index 6379534..d9c3003 100644
> --- a/arch/nios2/cpu/cpu.c
> +++ b/arch/nios2/cpu/cpu.c
> @@ -40,11 +40,13 @@ int checkcpu (void)
>  	return (0);
>  }
>  
> -
> -int do_reset (void)
> +int do_reset(void)
>  {
> -	void (*rst)(void) = (void(*)(void))CONFIG_SYS_RESET_ADDR;
> -	disable_interrupts ();
> -	rst();
> -	return(0);
> +	disable_interrupts();
> +	__asm__ __volatile__ (
> +	"callr	%0"
> +	:
> +	: "r" (CONFIG_SYS_RESET_ADDR)
> +	);
> +	return 0;
>  }
>