[POWERPC] Generic DCR infrastructure

This patch adds new dcr_map/dcr_read/dcr_write accessors for DCRs that
can be used by drivers to transparently address either native DCRs or
memory mapped DCRs. The implementation for memory mapped DCRs is done
after the binding being currently worked on for SLOF and the Axon
chipset. This patch enables it for the cell native platform

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 39 insertions, 0 deletions

diff --git a/arch/powerpc/sysdev/dcr-low.S b/arch/powerpc/sysdev/dcr-low.S
new file mode 100644
index 000000000000..2078f39e2f17
--- /dev/null
+++ b/arch/powerpc/sysdev/dcr-low.S
@@ -0,0 +1,39 @@
+/*
+ * "Indirect" DCR access
+ *
+ * Copyright (c) 2004 Eugene Surovegin <ebs@ebshome.net>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under  the terms of  the GNU General Public License as published by the
+ * Free Software Foundation;  either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#include <asm/ppc_asm.h>
+#include <asm/processor.h>
+
+#define DCR_ACCESS_PROLOG(table) \
+        rlwinm  r3,r3,4,18,27;   \
+        lis     r5,table@h;      \
+        ori     r5,r5,table@l;   \
+        add     r3,r3,r5;        \
+        mtctr   r3;              \
+        bctr
+
+_GLOBAL(__mfdcr)
+        DCR_ACCESS_PROLOG(__mfdcr_table)
+
+_GLOBAL(__mtdcr)
+        DCR_ACCESS_PROLOG(__mtdcr_table)
+
+__mfdcr_table:
+        mfdcr  r3,0; blr
+__mtdcr_table:
+        mtdcr  0,r4; blr
+
+dcr     = 1
+        .rept   1023
+        mfdcr   r3,dcr; blr
+        mtdcr   dcr,r4; blr
+        dcr     = dcr + 1
+        .endr