[coreboot] gfx_uma_size on GM45

[Arthur Heymans]

Hi

On gm45 targets there are some option to set different vram option using
the cmos parameter gfx_uma_size. The northbridge code however allows many
more option, ranging for 1M to 352M. 
So I tried making them an on option by modifying cmos.default and the
northbridge code that uses those cmos bits.
Now the size of this cmos parameter has to be increased for 3 to 4 bits
to be able to hold all those options.

My problem is that only the 3 smallest bits from the cmos parameter are
used.
The problem is truly there because hardcoding the vram size instead
works fine.

these are the changes I tried (at 256M it forgets highest bit and is
read as 0 in cmos and 1M is used):
--- a/src/mainboard/lenovo/x200/cmos.layout
+++ b/src/mainboard/lenovo/x200/cmos.layout
@@ -77,9 +77,9 @@ entries
 940         1       e       1        uwb
 
 # coreboot config options: northbridge
-941         3       e       11       gfx_uma_size
+941         4       e       11       gfx_uma_size
 
-944         8       h       0        volume
+945         8       h       0        volume
 
 # coreboot config options: check sums
 984          16       h       0        check_sum
@@ -125,12 +125,19 @@ enumerations
 9     1     Primary
 10    0     AHCI
 10    1     Compatible
-11    0     32M
-11    1     48M
-11    2     64M
-11    3     128M
-11    5     96M
-11    6     160M
+11    0     1M
+11    1     4M
+11    2     8M
+11    3     16M
+11    4     32M
+11    5     48M
+11    6     64M
+11    7     128M
+11    8     256M
+11    9     96M
+11    10    160M
+11    11    224M
+11    12    352M

--- a/src/northbridge/intel/gm45/igd.c
+++ b/src/northbridge/intel/gm45/igd.c
@@ -153,10 +153,10 @@ void igd_compute_ggc(sysinfo_t *const sysinfo)
 		/* Graphics Stolen Memory: 2MB GTT (0x0300) when VT-d disabled,
 		   2MB GTT + 2MB shadow GTT (0x0b00) else. */
 		if (get_option(&gfxsize, "gfx_uma_size") != CB_SUCCESS) {
-			/* 0 for 32MB */
-			gfxsize = 0;
+			/* 4 for 32MB, default if not set in cmos */
+			gfxsize = 4;
 		}
-		sysinfo->ggc = 0x0300 | ((gfxsize + 5) << 4);
+		sysinfo->ggc = 0x0300 | ((gfxsize + 1) << 4);
 		if (!(capid & (1 << (48 - 32))))
 			sysinfo->ggc |= 0x0800;
 	}


Kind regards
-- 
Arthur Heymans