[POWERPC] Early serial debug support for PPC44x

This adds support for early serial debugging via the built in
port on IBM/AMCC PowerPC 44x CPUs.  It uses a bolted TLB entry in
address space 1 for the UART's mapping, allowing robust debugging both
before and after the initialization of the MMU.

Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/asm-powerpc/mmu-44x.h b/include/asm-powerpc/mmu-44x.h
index 7bbc37e27d3c..d5ce7a8dfe9f 100644
--- a/include/asm-powerpc/mmu-44x.h
+++ b/include/asm-powerpc/mmu-44x.h
@@ -64,7 +64,13 @@ typedef struct {
 
 #endif /* !__ASSEMBLY__ */
 
+#ifndef CONFIG_PPC_EARLY_DEBUG_44x
 #define PPC44x_EARLY_TLBS       1
+#else
+#define PPC44x_EARLY_TLBS       2
+#define PPC44x_EARLY_DEBUG_VIRTADDR     (ASM_CONST(0xf0000000) \
+        | (ASM_CONST(CONFIG_PPC_EARLY_DEBUG_44x_PHYSLOW) & 0xffff))
+#endif
 
 /* Size of the TLBs used for pinning in lowmem */
 #define PPC_PIN_SIZE    (1 << 28)       /* 256M */