[PATCH] Fix v3 VIA C7 CAR disable

[Carl-Daniel Hailfinger]

The VIA C7 CAR disable code in v3 had a nasty bug which caused the
processor to reset. Fix this bug and actually disable CAR.
With this patch v3 has better C7 CAR code than v2 (which skips two key
MTRRs).

Thanks to Corey Osgood for testing countless debug patches.

Signed-off-by: Carl-Daniel Hailfinger

Attached for Gmail users.

Index: corebootv3-via_car/arch/x86/via/stage1.c
===================================================================
--- corebootv3-via_car/arch/x86/via/stage1.c	(Revision 980)
+++ corebootv3-via_car/arch/x86/via/stage1.c	(Arbeitskopie)
@@ -56,22 +56,20 @@
    __asm__ __volatile__(
    "	movl	%[newesp], %%esp	\n"

-#if ENABLE_BROKEN_CAR_DISABLING
    /* We don't need cache as ram for now on */
    /* disable cache */
    "	movl    %%cr0, %%eax		\n"
    "	orl    $(0x1<<30),%%eax		\n"
    "	movl    %%eax, %%cr0		\n"

-	/* The MTRR setup below causes the machine to reset. Must investigate. */
    /* disable fixed mtrr from now on, it will be enabled by coreboot_ram again*/
-	"	movl    %[_SYSCFG_MSR], %%ecx	\n"
-	"	rdmsr				\n"
-	"	andl    %[_SYSCFG_MSR_newval], %%eax\n"
-//	"	andl    $(~(SYSCFG_MSR_MtrrFixDramModEn | SYSCFG_MSR_MtrrFixDramEn)), %%eax\n"
    /* clear sth */
+	"	xorl    %%eax, %%eax		\n"
+	"	xorl    %%edx, %%edx		\n"
+	"	movl    $0x201, %%ecx		\n"
    "	wrmsr				\n"
-#warning Must clear MTRR 0x200 and 0x201
+	"	movl    $0x200, %%ecx		\n"
+	"	wrmsr				\n"

/* Set the default memory type and disable fixed and enable variable MTRRs */
    "	movl    %[_MTRRdefType_MSR], %%ecx	\n"
@@ -84,16 +82,11 @@
    "	movl    %%cr0, %%eax		\n"
    "	andl    $0x9fffffff,%%eax	\n"
    "	movl    %%eax, %%cr0		\n"
-#endif

"	wbinvd				\n"

"	call stage1_phase3		\n"
    :: [newesp] "i" (newlocation),
-	 [_SYSCFG_MSR] "i" (SYSCFG_MSR),
-	 [_SYSCFG_MSR_newval] "i" (~(SYSCFG_MSR_MtrrFixDramModEn | SYSCFG_MSR_MtrrFixDramEn)),
-	 [_SYSCFG_MSR_MtrrFixDramModEn] "i" (SYSCFG_MSR_MtrrFixDramModEn),
-	 [_SYSCFG_MSR_MtrrFixDramEn] "i" (SYSCFG_MSR_MtrrFixDramEn),
     [_MTRRdefType_MSR] "i" (MTRRdefType_MSR)
    : "memory");
 }

[ron minnich]

Acked-by: Ronald G. Minnich

and thanks to both of you. FIne work!

ron

[Carl-Daniel Hailfinger]

On 05.11.2008 06:00, ron minnich wrote:
> Acked-by: Ronald G. Minnich
>
> and thanks to both of you. FIne work!

Corey? I'd appreciate if you could ack this patch as well since you did
the heavy lifting in the testing department.

Thanks,
Carl-Daniel

[Carl-Daniel Hailfinger]

On 05.11.2008 06:00, ron minnich wrote:
> Acked-by: Ronald G. Minnich

Thanks, r1010.
> and thanks to both of you. FIne work!

Yes, thanks to Corey for countless tests and a lot of persistence.

Regards,
Carl-Daniel