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gxfb/lxfb: detect framebuffer size using an MSR if VSA2 isn't available

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If there's no VSA2 (ie, if we're using tinybios or OpenFirmware), use the
GLIU's P2D Range Offset Descriptor to determine how much memory we have
available for the framebuffer.

Originally based on a patch by Jordan Crouse.  Tested with OpenFirmware;
Pascal informs me that tinybios has a stub that fills in P2D_RO0.

Signed-off-by: Andres Salomon <dilinger@debian.org>
Cc: Jordan Crouse <jordan.crouse@amd.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andres Salomon 2008-04-28 02:15:30 -07:00 committed by Linus Torvalds
parent 61a517a063
commit fd96795630
3 changed files with 35 additions and 1 deletions
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18
drivers/video/geode/display_gx.c
View file

@ -25,7 +25,23 @@ unsigned int gx_frame_buffer_size(void)
{
unsigned int val;
/* FB size is reported by a virtual register */
if (!geode_has_vsa2()) {
uint32_t hi, lo;
/* The number of pages is (PMAX - PMIN)+1 */
rdmsr(MSR_GLIU_P2D_RO0, lo, hi);
/* PMAX */
val = ((hi & 0xff) << 12) | ((lo & 0xfff00000) >> 20);
/* PMIN */
val -= (lo & 0x000fffff);
val += 1;
/* The page size is 4k */
return (val << 12);
}
/* FB size can be obtained from the VSA II */
/* Virtual register class = 0x02 */
/* VG_MEM_SIZE(512Kb units) = 0x00 */

16
drivers/video/geode/lxfb_ops.c
View file

@ -329,6 +329,22 @@ unsigned int lx_framebuffer_size(void)
{
unsigned int val;
if (!geode_has_vsa2()) {
uint32_t hi, lo;
/* The number of pages is (PMAX - PMIN)+1 */
rdmsr(MSR_GLIU_P2D_RO0, lo, hi);
/* PMAX */
val = ((hi & 0xff) << 12) | ((lo & 0xfff00000) >> 20);
/* PMIN */
val -= (lo & 0x000fffff);
val += 1;
/* The page size is 4k */
return (val << 12);
}
/* The frame buffer size is reported by a VSM in VSA II */
/* Virtual Register Class = 0x02 */
/* VG_MEM_SIZE (1MB units) = 0x00 */

2
include/asm-x86/geode.h
View file

@ -30,6 +30,8 @@ extern int geode_get_dev_base(unsigned int dev);
/* MSRS */
#define MSR_GLIU_P2D_RO0 0x10000029
#define MSR_LX_GLD_MSR_CONFIG 0x48002001
#define MSR_LX_MSR_PADSEL 0x48002011 /* NOT 0x48000011; the data
* sheet has the wrong value */