[POWERPC] Refactor DCR code

Previously, DCR support was configured at compile time to either use
MMIO or native dcr instructions.  Although this works for most
platforms, it fails on FPGA platforms:

1) Systems may include more than one DCR bus.
2) Systems may be native DCR capable and still use memory mapped DCR interface.

This patch provides runtime support based on the device trees for the
case where CONFIG_PPC_DCR_MMIO and CONFIG_PPC_DCR_NATIVE are both
selected.  Previously, this was a poorly defined configuration, which
happened to provide NATIVE support.  The runtime selection is made
based on the dcr-controller having a 'dcr-access-method' attribute
in the device tree.  If only one of the above options is selected,
then the code uses #defines to select only the used code in order to
avoid introducing overhead in existing usage.

Signed-off-by: Stephen Neuendorffer <stephen.neuendorffer@xilinx.com>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>

1 files changed, 49 insertions, 0 deletions

diff --git a/include/asm-powerpc/dcr-generic.h b/include/asm-powerpc/dcr-generic.h
new file mode 100644
index 000000000000..35b71599ec46
--- /dev/null
+++ b/include/asm-powerpc/dcr-generic.h
@@ -0,0 +1,49 @@
+/*
+ * (c) Copyright 2006 Benjamin Herrenschmidt, IBM Corp.
+ *                    <benh@kernel.crashing.org>
+ *
+ *   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_GENERIC_H
+#define _ASM_POWERPC_DCR_GENERIC_H
+#ifdef __KERNEL__
+#ifndef __ASSEMBLY__
+
+enum host_type_t {DCR_HOST_MMIO, DCR_HOST_NATIVE, DCR_HOST_INVALID};
+
+typedef struct {
+        enum host_type_t type;
+        union {
+                dcr_host_mmio_t mmio;
+                dcr_host_native_t native;
+        } host;
+} dcr_host_t;
+
+extern bool dcr_map_ok_generic(dcr_host_t host);
+
+extern dcr_host_t dcr_map_generic(struct device_node *dev, unsigned int dcr_n,
+                          unsigned int dcr_c);
+extern void dcr_unmap_generic(dcr_host_t host, unsigned int dcr_c);
+
+extern u32 dcr_read_generic(dcr_host_t host, unsigned int dcr_n);
+
+extern void dcr_write_generic(dcr_host_t host, unsigned int dcr_n, u32 value);
+
+#endif /* __ASSEMBLY__ */
+#endif /* __KERNEL__ */
+#endif /* _ASM_POWERPC_DCR_GENERIC_H */
+
+