[PATCH] sparc32,leon: fix leon bootup

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>From 1ea4052166ab9c09a4a591bb59dafbcb188d1add Mon Sep 17 00:00:00 2001
From: Sam Ravnborg <sam@xxxxxxxxxxxx>
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@xxxxxxxxxxx>
Signed-off-by: Sam Ravnborg <sam@xxxxxxxxxxxx>
---

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.

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
+		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
 
-- 
1.6.0.6

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