Changeset bab785fe in mainline

Timestamp:

2006-06-18T12:03:01Z (19 years ago)

Author:

Martin Decky <martin@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

60316bd

Parents:

a88ab795

Message:

pick the best BAT mapping

Location:

arch/ppc32/loader

Files:

• asm.S (modified) (4 diffs)
• debug.inc (modified) (1 diff)

arch/ppc32/loader/asm.S

@@ -196 +196 @@
         li r29, 8
         mtctr r29
-        li r30, 0
+        li r30, 0                     # ASID 0 (VSIDs 0 .. 7)
 
         seg_fill_uspace:
@@ -208 +208 @@
         li r29, 8
         mtctr r29
-        lis r30, 0x4000
-        ori r30, r30, 8
+        lis r30, 0x4000               # priviledged access only
+        ori r30, r30, 8               # ASID 0 (VSIDs 8 .. 15)
         
         seg_fill_kernel:
@@ -261 +261 @@
         pht_clear:
                 
+                # write zeroes
+                
                 stw r29, 0(r31)
                 
@@ -280 +282 @@
         mtsdr1 r31
         
-        # create identity mapping
-        
 #ifdef CONFIG_BAT
         
+        # create BAT identity mapping
+        
         DEBUG_mapping
         
-        # FIXME: map exactly the size of RAM
-        
-        lis r31, 0x8000
-        ori r31, r31, 0x0ffe
+        lwz r31, 0(r3)
+        
+        lis r29, 0x0002
+        cmpw r31, r29
+        blt no_bat                    # less than 128 KB -> no BAT
+        
+        li r29, 18
+        srw r31, r31, r29             # r31 = total >> 18
+        
+        # create Block Length mask by replicating
+        # the leading logical one 14 times
+        
+        li r29, 14
+        mtctr r31
+        li r29, 1
+        
+        bat_mask:
+                srw r30, r31, r29         # r30 = mask >> 1
+                or r31, r31, r30          # mask = mask | r30
+                
+                bdnz bat_mask
+        
+        andi. r31, r31, 0x07ff        # mask = mask & 0x07ff (BAT can map up to 256 MB)
+        
+        li r29, 2
+        slw r31, r31, r29             # mask = mask << 2
+        ori r31, r31, 0x0002          # mask = mask | 0x0002 (priviledged access only)
+        
+        lis r29, 0x8000
+        or r29, r29, r31
         
         lis r30, 0x0000
         ori r30, r30, 0x0002
         
-        mtspr ibat0u, r31
+        mtspr ibat0u, r29
         mtspr ibat0l, r30
         
-        mtspr dbat0u, r31
+        mtspr dbat0u, r29
         mtspr dbat0l, r30
+        
+        no_bat:
 
 #endif

arch/ppc32/loader/debug.inc

@@ -8308 +8308 @@
 #endif
 .endm
+
+.macro DEBUG_bat_mask
+#ifdef CONFIG_DEBUG
+#endif
+.endm