[PATCH] Clean-up and bug fix for tdfxfb framebuffer size detection

Attached is a patch against 2.6.11.7 which tidies up the tdfxfb framebuffer
size detection code a little and fixes the broken support for Voodoo4/5
cards.  (I haven't tested this on a Voodoo5, however, because I don't have
the hardware).

Signed-off-by: Richard Drummond <evilrich@rcdrummond.net>
Cc: <linux-fbdev-devel@lists.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 24 insertions, 23 deletions

diff --git a/drivers/video/tdfxfb.c b/drivers/video/tdfxfb.c
index c8b0be2d8715..7044226c5d4c 100644
--- a/drivers/video/tdfxfb.c
+++ b/drivers/video/tdfxfb.c
@@ -430,36 +430,35 @@ static void do_write_regs(struct fb_info *info, struct banshee_reg* reg)
 
 static unsigned long do_lfb_size(struct tdfx_par *par, unsigned short dev_id) 
 {
-        u32 draminit0 = 0;
-        u32 draminit1 = 0;
-        u32 miscinit1 = 0;
-        u32 lfbsize   = 0;
-        int sgram_p   = 0;
+        u32 draminit0;
+        u32 draminit1;
+        u32 miscinit1;
+
+        int num_chips;
+        int chip_size; /* in MB */
+        u32 lfbsize;
+        int has_sgram;
 
         draminit0 = tdfx_inl(par, DRAMINIT0);  
         draminit1 = tdfx_inl(par, DRAMINIT1);
+
+        num_chips = (draminit0 & DRAMINIT0_SGRAM_NUM) ? 8 : 4;
  
-        if ((dev_id == PCI_DEVICE_ID_3DFX_BANSHEE) ||
-            (dev_id == PCI_DEVICE_ID_3DFX_VOODOO3)) {                    
-                sgram_p = (draminit1 & DRAMINIT1_MEM_SDRAM) ? 0 : 1;
-  
-        lfbsize = sgram_p ?
-                (((draminit0 & DRAMINIT0_SGRAM_NUM)  ? 2 : 1) * 
-                ((draminit0 & DRAMINIT0_SGRAM_TYPE) ? 8 : 4) * 1024 * 1024) :
-                16 * 1024 * 1024;
+        if (dev_id < PCI_DEVICE_ID_3DFX_VOODOO5) {
+                /* Banshee/Voodoo3 */
+                has_sgram = draminit1 & DRAMINIT1_MEM_SDRAM;
+                chip_size = has_sgram ? ((draminit0 & DRAMINIT0_SGRAM_TYPE) ? 2 : 1)
+                                      : 2;
         } else {
                 /* Voodoo4/5 */
-                u32 chips, psize, banks;
-
-                chips = ((draminit0 & (1 << 26)) == 0) ? 4 : 8;
-                psize = 1 << ((draminit0 & 0x38000000) >> 28);
-                banks = ((draminit0 & (1 << 30)) == 0) ? 2 : 4;
-                lfbsize = chips * psize * banks;
-                lfbsize <<= 20;
-        }                 
-        /* disable block writes for SDRAM (why?) */
+                has_sgram = 0;
+                chip_size = 1 << ((draminit0 & DRAMINIT0_SGRAM_TYPE_MASK) >> DRAMINIT0_SGRAM_TYPE_SHIFT);
+        }
+        lfbsize = num_chips * chip_size * 1024 * 1024;
+
+        /* disable block writes for SDRAM */
         miscinit1 = tdfx_inl(par, MISCINIT1);
-        miscinit1 |= sgram_p ? 0 : MISCINIT1_2DBLOCK_DIS;
+        miscinit1 |= has_sgram ? 0 : MISCINIT1_2DBLOCK_DIS;
         miscinit1 |= MISCINIT1_CLUT_INV;
 
         banshee_make_room(par, 1); 
diff --git a/include/video/tdfx.h b/include/video/tdfx.h
index a896e4442060..04237676b17c 100644
--- a/include/video/tdfx.h
+++ b/include/video/tdfx.h
@@ -99,6 +99,8 @@
 #define MISCINIT1_2DBLOCK_DIS           BIT(15)
 #define DRAMINIT0_SGRAM_NUM             BIT(26)
 #define DRAMINIT0_SGRAM_TYPE            BIT(27)
+#define DRAMINIT0_SGRAM_TYPE_MASK       (BIT(27)|BIT(28)|BIT(29))
+#define DRAMINIT0_SGRAM_TYPE_SHIFT      27
 #define DRAMINIT1_MEM_SDRAM             BIT(30)
 #define VGAINIT0_VGA_DISABLE            BIT(0)
 #define VGAINIT0_EXT_TIMING             BIT(1)