Changeset 3debedec in mainline for arch/ppc32/src/start.S

Timestamp:

2006-02-16T20:26:14Z (19 years ago)

Author:

Ondrej Palkovsky <ondrap@…>

Branches:

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

Children:

ba52899

Parents:

2a46e10

Message:

Made powerpc to get on PearPC to the version print when compiled with -O1:

• create proper memory zones
• switch to real mode on boot

TODO

• kernel relocation during boot
• autodetection of framebuffer settings (PCI?) - now includes hardcoded settings for PearPc.

File:

• arch/ppc32/src/start.S (modified) (3 diffs)

arch/ppc32/src/start.S

@@ -28 +28 @@
 
 #include <arch/asm/macro.h>
+#include <arch/asm/spr.h>
 
 .section K_TEXT_START
@@ -33 +34 @@
 .global kernel_image_start
 
+.org 0x0
+/* 256 bytes of some data */
+/* exception table - must use 'ba' instructions for branches,
+ * because it is elsewhere than the linker thinks
+ */
+.space 4096
+
 kernel_image_start:
+        /* Initialize OFW, might be needed before relocate_kernel? */
         lis r4, ofw@ha
         addi r4, r4, ofw@l
@@ -39 +48 @@
         
         bl ofw_init
+        bl preboot_read_config
+
+        bl relocate_kernel
+__after_reloc:
+        /* Set stack to some more meaningful value */
+        /* TODO: This is hardcoded for PearPC, must be changed later */
+        lis r1, 0x70
+        b main_bsp
         
-        b main_bsp
+relocate_kernel:
+        /* TODO: We _know_ that pearpc loads it to 8MB, and
+         * but it should be really generic
+         */
+        lis r4, 0x80 /* r4 is where data was loaded - 8MB */
+        
+        bl to_real_mode
+        /* Now we are in real mode, copy first block and jump to it,
+         * we are running in the loaded kernel now
+         * We still have in r3 physical load kernel address
+         */
+        
+        b __after_reloc /* We know in pearpc we are ok, so return,
+                         * otherwise we should relocate kernel
+                         * here
+                         */
+
+        
+
+        
+/* Turn off page translation
+ * - assume that physical-loaded address is in r4
+ */
+to_real_mode:
+        mflr r0
+        
+        lis   r5, ktext_start@ha // Expected start of kernel
+        addi r5, r5, ktext_start@l
+        
+        add  r0, r4, r0         
+        sub  r0, r0, r5         // r0 now contains physical return address
+        
+        mfmsr r3
+        andis. r3, r3, (~MSR_DR | MSR_IR) >> 16
+        mtspr SPRN_SRR0, r0
+        mtspr SPRN_SRR1, r3
+        sync                    // Really needed? RFI should do it as well?
+        RFI
+