From d9b55a03611ff2e2e54fb4e1ad2648d5eb870fa3 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Tue, 8 May 2007 12:59:31 +1000 Subject: [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 Signed-off-by: Paul Mackerras --- arch/powerpc/platforms/44x/misc_44x.S | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'arch/powerpc/platforms/44x/misc_44x.S') diff --git a/arch/powerpc/platforms/44x/misc_44x.S b/arch/powerpc/platforms/44x/misc_44x.S index 52bde71..3bce71d 100644 --- a/arch/powerpc/platforms/44x/misc_44x.S +++ b/arch/powerpc/platforms/44x/misc_44x.S @@ -15,6 +15,37 @@ .text /* + * Do an IO access in AS1 + */ +_GLOBAL(as1_readb) + mfmsr r7 + ori r0,r7,MSR_DS + sync + mtmsr r0 + sync + isync + lbz r3,0(r3) + sync + mtmsr r7 + sync + isync + blr + +_GLOBAL(as1_writeb) + mfmsr r7 + ori r0,r7,MSR_DS + sync + mtmsr r0 + sync + isync + stb r3,0(r4) + sync + mtmsr r7 + sync + isync + blr + +/* * void ppc44x_reset_system(char *cmd) * * At present, this routine just applies a system reset. -- cgit v1.1