Ѕubject: powerpc: generic DCR access

The Axon chip has a MMIO accessed DCR bus.  This patch add
abstract access to DCR registers for any DCR based device drivers.

Signed-off-by: Shaun Wetzstein <shaun@vnet.ibm.com>

Index: linux-2.6/include/asm-powerpc/dcr.h
===================================================================
--- /dev/null
+++ linux-2.6/include/asm-powerpc/dcr.h
@@ -0,0 +1,56 @@
+/*
+ *   Copyright (c) International Business Machines Corp., 2006
+ *
+ *   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.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
+ *   the GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program;  if not, write to the Free Software
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#ifndef _ASM_POWERPC_DCR_H
+#define _ASM_POWERPC_DCR_H
+#ifdef __KERNEL__
+
+#include <asm/of_device.h>
+
+#if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
+inline void *dcr_find_controller(struct device_node *node)
+
+{
+	return NULL;
+}
+
+#include <asm/reg.h>
+
+inline u32 dcr_read(void *, int dcr_n)
+{
+	return mfdcr(dcr_n);
+}
+
+inline void dcr_write(void *, int dcr_n, u32 value)
+{
+	mtdcr(dcr_n, value);
+}
+#else /* for systems without mtdcr/mfdcr */
+
+/*
+    given a DCR based device node, search up the dt for the
+    "owning" dcr controller node and return its token
+*/
+extern void *dcr_find_controller(struct device_node *);
+
+extern u32 dcr_read(void *, int);
+extern void dcr_write(void *, int, u32);
+#endif
+
+#endif /* __KERNEL__ */
+#endif /* _ASM_POWERPC_DCR_H */
Index: linux-2.6/arch/powerpc/Kconfig
===================================================================
--- linux-2.6.orig/arch/powerpc/Kconfig
+++ linux-2.6/arch/powerpc/Kconfig
@@ -160,9 +160,11 @@ config PPC_86xx
 
 config 40x
 	bool "AMCC 40x"
+	select PPC_DCR
 
 config 44x
 	bool "AMCC 44x"
+	select PPC_DCR
 
 config 8xx
 	bool "Freescale 8xx"
@@ -445,6 +447,7 @@ config PPC_CELL
 config PPC_CELL_NATIVE
 	bool
 	select PPC_CELL
+	select PPC_DCR
 	default n
 
 config PPC_IBM_CELL_BLADE
@@ -526,6 +529,10 @@ config MPIC_BROKEN_U3
 	depends on PPC_MAPLE
 	default y
 
+config PPC_DCR
+	bool
+	default n
+
 config IBMVIO
 	depends on PPC_PSERIES || PPC_ISERIES
 	bool