Changeset b5a3b50 in mainline for boot/arch/arm32/src/asm.S

Timestamp:

2012-12-31T08:41:10Z (12 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

029e3cc, 17cc8f4f, 660e8fa, 664fd6d5

Parents:

b55877d

git-author:

Beniamino Galvani <b.galvani@…> (2012-12-31 08:41:10)

git-committer:

Jakub Jermar <jakub@…> (2012-12-31 08:41:10)

Message:

Enable ARM caches in the boot stage of HelenOS to speed up the
decompression. We get a decompression time of 8 seconds on a mini2440
board and only slightly more on a GTA02.

File:

• boot/arch/arm32/src/asm.S (modified) (1 diff)

boot/arch/arm32/src/asm.S

@@ -60 +60 @@
         # before passing control to the copied code.
         #
+
+#if defined(MACHINE_gta02)
+
+#define CP15_C1_IC              12
+#define CP15_C1_DC              2
+#define CP15_C7_SEG_SHIFT       5
+#define CP15_C7_SEG_SIZE        3
+#define CP15_C7_IDX_SHIFT       26
+
+        # Disable I-cache and D-cache before the kernel is started.
+        mrc     p15, 0, r4, c1, c0, 0
+        bic     r4, r4, #(1 << CP15_C1_DC)
+        bic     r4, r4, #(1 << CP15_C1_IC)
+        mcr     p15, 0, r4, c1, c0, 0
+
+        # Now clean D-cache to guarantee coherency between I-cache and D-cache.
+
+        # D-cache clean and invalidate procedure.
+        # See ARM920T TRM pages 2-17, 4-17.
+
+        # Initialize segment
+        mov     r4, #0
+        # Initialize index
+1:      mov     r5, #0
+2:      orr     r6, r4, r5
+        # Clean and invalidate a single line
+        mcr     p15, 0, r6, c7, c10, 2
+        # Increment index
+        add     r5, r5, #(1 << CP15_C7_IDX_SHIFT)
+        cmp     r5, #0
+        bne     2b
+        # Increment segment
+        add     r4, #(1 << CP15_C7_SEG_SHIFT)
+        tst     r4, #(1 << (CP15_C7_SEG_SHIFT + CP15_C7_SEG_SIZE))
+        beq     1b
+#endif
+
         mov pc, r0