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

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>

diff --git a/drivers/video/geode/display_gx.c b/drivers/video/geode/display_gx.c
index 1e82ecc367dd259cf78863a6a32a5df6b65985f7..e759895bf3d3d19deb02ec6323f7c8ff646b96fc 100644 (file)
--- a/drivers/video/geode/display_gx.c
+++ b/drivers/video/geode/display_gx.c
@@ -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 */
 

diff --git a/drivers/video/geode/lxfb_ops.c b/drivers/video/geode/lxfb_ops.c
index e42e12489f6db25c2b926bc8ad34e18dfec562da..cd9d4cc269549932008ac90ee9a37a744312941d 100644 (file)
--- a/drivers/video/geode/lxfb_ops.c
+++ b/drivers/video/geode/lxfb_ops.c
@@ -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                     */

diff --git a/include/asm-x86/geode.h b/include/asm-x86/geode.h
index 4fb2f62e277bdd62c5db89a658c3ee6914d31343..7154dc4de9511692c5417973ac866f4883d2d7c3 100644 (file)
--- a/include/asm-x86/geode.h
+++ b/include/asm-x86/geode.h
@@ -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 */