[PATCH] v3: rework Geode LX RAMinit DIMM size formula

[Carl-Daniel Hailfinger]

Rework Geode LX RAMinit DIMM size formula to be more
understandable. Added benefit is complaining loudly for
unsupported 2 GB DIMM size.

Signed-off-by: Carl-Daniel Hailfinger

Index: LinuxBIOSv3-stuff/northbridge/amd/geodelx/raminit.c
===================================================================
--- LinuxBIOSv3-stuff/northbridge/amd/geodelx/raminit.c	(Revision 659)
+++ LinuxBIOSv3-stuff/northbridge/amd/geodelx/raminit.c	(Arbeitskopie)
@@ -151,16 +151,12 @@
    banner(BIOS_DEBUG, "SPDBANKDENSITY");
    dimm_size = spd_read_byte(dimm, SPD_BANK_DENSITY);

-	/* Align so 1 GB (bit 0) is bit 8. This is a little weird to get gcc
-	 * to not optimize this out.
+	/* Bits 0-1 have been redefined by JEDEC to contain what would have
+	 * been in non-existing bits 8 (1GB) and 9 (2GB). Move bits 0-1 to
+	 * bits 8-9 and mask bits 0-1 off.
     */
-	dimm_size |= (dimm_size << 8);
+	dimm_size = ((dimm_size & 0x3) << 8) | (dimm_size & ~0x3);

-	/* And off 2 GB DIMM size: not supported and the 1 GB size we just
-	 * moved up to bit 8 as well as all the extra on top.
-	 */
-	dimm_size &= 0x01FC;
-
    /* Module Density * Module Banks */
    /* Shift to multiply by the number of DIMM banks. */
    dimm_size <<= (dimm_setting >> CF07_UPPER_D0_MB_SHIFT) & 1;

[ron minnich]

On Tue, Apr 29, 2008 at 4:10 PM, Carl-Daniel Hailfinger
 wrote:
> Rework Geode LX RAMinit DIMM size formula to be more
>  understandable. Added benefit is complaining loudly for
>  unsupported 2 GB DIMM size.
>
> Signed-off-by: Carl-Daniel Hailfinger

Tested on the dbe62 up to and including Etherboot.

Acked-by: Ronald G. Minnich 
Committed revision 671.

[Carl-Daniel Hailfinger]

On 30.04.2008 06:13, ron minnich wrote:
> On Tue, Apr 29, 2008 at 4:10 PM, Carl-Daniel Hailfinger
>  wrote:
> > Rework Geode LX RAMinit DIMM size formula to be more
> >  understandable. Added benefit is complaining loudly for
> >  unsupported 2 GB DIMM size.
> >
> > Signed-off-by: Carl-Daniel Hailfinger
>
> Tested on the dbe62 up to and including Etherboot.
>
> Acked-by: Ronald G. Minnich 
> Committed revision 671.

Thanks!

Regards,
Carl-Daniel