Re: [PATCH] sparc32,leon: fix leon bootup

[Daniel Hellstrom <daniel@gaisler.com>]

On 05/28/2012 10:51 PM, Sam Ravnborg wrote:
> > From 1ea4052166ab9c09a4a591bb59dafbcb188d1add Mon Sep 17 00:00:00 2001
> From: Sam Ravnborg<sam@ravnborg.org>
> Date: Mon, 28 May 2012 22:44:44 +0200
> Subject: [PATCH] sparc32,leon: fix leon bootup
>
> head_32.S failed to set cputypval for leon, causing boot to fail.
> The boot failed because we failed to recognize this was a LEON
> cpu so we did not preoperly run-time patch the the kernel.
> This resulted in an early crash.
>
> Refactor head_32.S such that we always determine the cpu
> model based on the getprops("compatible") call.
> this resulted in cleaner code.
>
> We continue to recognize the LEON cpu
> using PSR in the very early boot phase.
>
> Reported-by: Daniel Hellstrom<daniel@gaisler.com>
> Signed-off-by: Sam Ravnborg<sam@ravnborg.org>
> ---
>
> I checked that this could build - but I did not boot-test it on my ss5.
> I aimed for the cleaner solution - not the simplest solution.
>
> Please test and let us know if this fixes leon boot-up.

It fails, after fixing the typo it works, please see comment below.

> Thanks in advance,
>
> 	Sam
>
>
>   arch/sparc/kernel/head_32.S |   73 ++++++++++++++++++++++++-------------------
>   1 files changed, 41 insertions(+), 32 deletions(-)
>
> diff --git a/arch/sparc/kernel/head_32.S b/arch/sparc/kernel/head_32.S
> index cdc7f29..c2c9371 100644
> --- a/arch/sparc/kernel/head_32.S
> +++ b/arch/sparc/kernel/head_32.S
> @@ -372,36 +372,9 @@ execute_in_high_mem:
>   		sethi	%hi(linux_dbvec), %g1
>   		st	%o1, [%g1 + %lo(linux_dbvec)]
>
> -		/* Check if this is a LEON CPU.
> -		 * Skip getprops call if it is
> +		/* Get the machine type via the romvec
> +		 * getprops node operation
>   		 */
> -		srl	%g3, PSR_IMPL_SHIFT, %g3
> -		and	%g3, PSR_IMPL_SHIFTED_MASK, %g3
> -		cmp	%g3, PSR_IMPL_LEON
> -		 bne	get_cputype
> -
> -
> -		/* LEON CPU - set boot_cpu_id */
> -		sethi	%hi(boot_cpu_id), %g2	! boot-cpu index
> -
> -#ifdef CONFIG_SMP
> -		ldub	[%g2 + %lo(boot_cpu_id)], %g1
> -		cmp	%g1, 0xff		! unset means first CPU
> -		bne	leon_smp_cpu_startup	! continue only with master
> -		 nop
> -#endif
> -		/* Get CPU-ID from most significant 4-bit of ASR17 */
> -		rd     %asr17, %g1
> -		srl    %g1, 28, %g1
> -
> -		/* Update boot_cpu_id only on boot cpu */
> -		stub	%g1, [%g2 + %lo(boot_cpu_id)]
> -
> -		ba continue_boot
> -		 nop
> -
> -/* Get the machine type via the mysterious romvec node operations. */
> -get_cputype:
>   		add	%g7, 0x1c, %l1
>   		ld	[%l1], %l0
>   		ld	[%l0], %l0
> @@ -420,10 +393,26 @@ get_cputype:
>   						! to a buf where above string
>   						! will get stored by the prom.
>
> -/* Check to cputype. We may be booted on a sun4u (64 bit box),
> - * and sun4d needs special treatment.
> - */
> +
> +		/* Check value of "compatible" property.
> +		 * "value" =>  "model"
> +		 * leon =>  sparc_leon
> +		 * sun4m =>  sun4m
> +		 * sun4s =>  sun4m
> +		 * sun4d =>  sun4d
> +		 * sun4e =>  "no_sun4e_here"
> +		 * '*'   =>  "no_sun4u_here"
> +		 * Check single letters only
> +		 */
> +
>   		set	cputypval, %o2
> +		/* If cputypval[0] = 'l' (lower case letter L) this is leon
Missing end of comment here. Please add a */

After fixing this it works.

Thanks,
Daniel

> +		ldub	[%o2], %l1
> +		cmp	%l1, 'l'
> +		be	leon_init
> +		 nop
> +
> +		/* Check cputypval[4] to find the sun model */
>   		ldub	[%o2 + 0x4], %l1
>
>   		cmp	%l1, 'm'
> @@ -438,6 +427,26 @@ get_cputype:
>   		b	no_sun4u_here		! AIEEE, a V9 sun4u... Get our BIG BROTHER kernel :))
>   		 nop
>
> +leon_init:
> +		/* LEON CPU - set boot_cpu_id */
> +		sethi	%hi(boot_cpu_id), %g2	! boot-cpu index
> +
> +#ifdef CONFIG_SMP
> +		ldub	[%g2 + %lo(boot_cpu_id)], %g1
> +		cmp	%g1, 0xff		! unset means first CPU
> +		bne	leon_smp_cpu_startup	! continue only with master
> +		 nop
> +#endif
> +		/* Get CPU-ID from most significant 4-bit of ASR17 */
> +		rd     %asr17, %g1
> +		srl    %g1, 28, %g1
> +
> +		/* Update boot_cpu_id only on boot cpu */
> +		stub	%g1, [%g2 + %lo(boot_cpu_id)]
> +
> +		ba continue_boot
> +		 nop
> +
>   /* CPUID in bootbus can be found at PA 0xff0140000 */
>   #define SUN4D_BOOTBUS_CPUID     0xf0140000
>