[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, 38 insertions, 1 deletions

diff --git a/include/asm-powerpc/dcr.h b/include/asm-powerpc/dcr.h
index 9338d50538f..53b283050ab 100644
--- a/include/asm-powerpc/dcr.h
+++ b/include/asm-powerpc/dcr.h
@@ -20,14 +20,50 @@
 #ifndef _ASM_POWERPC_DCR_H
 #define _ASM_POWERPC_DCR_H
 #ifdef __KERNEL__
+#ifndef __ASSEMBLY__
 #ifdef CONFIG_PPC_DCR
 
 #ifdef CONFIG_PPC_DCR_NATIVE
 #include <asm/dcr-native.h>
-#else
+#endif
+
+#ifdef CONFIG_PPC_DCR_MMIO
 #include <asm/dcr-mmio.h>
 #endif
 
+
+/* Indirection layer for providing both NATIVE and MMIO support. */
+
+#if defined(CONFIG_PPC_DCR_NATIVE) && defined(CONFIG_PPC_DCR_MMIO)
+
+#include <asm/dcr-generic.h>
+
+#define DCR_MAP_OK(host)	dcr_map_ok_generic(host)
+#define dcr_map(dev, dcr_n, dcr_c) dcr_map_generic(dev, dcr_n, dcr_c)
+#define dcr_unmap(host, dcr_c) dcr_unmap_generic(host, dcr_c)
+#define dcr_read(host, dcr_n) dcr_read_generic(host, dcr_n)
+#define dcr_write(host, dcr_n, value) dcr_write_generic(host, dcr_n, value)
+
+#else
+
+#ifdef CONFIG_PPC_DCR_NATIVE
+typedef dcr_host_native_t dcr_host_t;
+#define DCR_MAP_OK(host)	dcr_map_ok_native(host)
+#define dcr_map(dev, dcr_n, dcr_c) dcr_map_native(dev, dcr_n, dcr_c)
+#define dcr_unmap(host, dcr_c) dcr_unmap_native(host, dcr_c)
+#define dcr_read(host, dcr_n) dcr_read_native(host, dcr_n)
+#define dcr_write(host, dcr_n, value) dcr_write_native(host, dcr_n, value)
+#else
+typedef dcr_host_mmio_t dcr_host_t;
+#define DCR_MAP_OK(host)	dcr_map_ok_mmio(host)
+#define dcr_map(dev, dcr_n, dcr_c) dcr_map_mmio(dev, dcr_n, dcr_c)
+#define dcr_unmap(host, dcr_c) dcr_unmap_mmio(host, dcr_c)
+#define dcr_read(host, dcr_n) dcr_read_mmio(host, dcr_n)
+#define dcr_write(host, dcr_n, value) dcr_write_mmio(host, dcr_n, value)
+#endif
+
+#endif /* defined(CONFIG_PPC_DCR_NATIVE) && defined(CONFIG_PPC_DCR_MMIO) */
+
 /*
  * On CONFIG_PPC_MERGE, we have additional helpers to read the DCR
  * base from the device-tree
@@ -41,5 +77,6 @@ extern unsigned int dcr_resource_len(struct device_node *np,
 #endif /* CONFIG_PPC_MERGE */
 
 #endif /* CONFIG_PPC_DCR */
+#endif /* __ASSEMBLY__ */
 #endif /* __KERNEL__ */
 #endif /* _ASM_POWERPC_DCR_H */