[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>

4 files changed, 110 insertions, 14 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 */
+
+
diff --git a/include/asm-powerpc/dcr-mmio.h b/include/asm-powerpc/dcr-mmio.h
index 08532ff1899c..acd491dbd45a 100644
--- a/include/asm-powerpc/dcr-mmio.h
+++ b/include/asm-powerpc/dcr-mmio.h
@@ -27,20 +27,26 @@ typedef struct {
         void __iomem *token;
         unsigned int stride;
         unsigned int base;
-} dcr_host_t;
+} dcr_host_mmio_t;
 
-#define DCR_MAP_OK(host)        ((host).token != NULL)
+static inline bool dcr_map_ok_mmio(dcr_host_mmio_t host)
+{
+        return host.token != NULL;
+}
 
-extern dcr_host_t dcr_map(struct device_node *dev, unsigned int dcr_n,
-                          unsigned int dcr_c);
-extern void dcr_unmap(dcr_host_t host, unsigned int dcr_c);
+extern dcr_host_mmio_t dcr_map_mmio(struct device_node *dev,
+                                    unsigned int dcr_n,
+                                    unsigned int dcr_c);
+extern void dcr_unmap_mmio(dcr_host_mmio_t host, unsigned int dcr_c);
 
-static inline u32 dcr_read(dcr_host_t host, unsigned int dcr_n)
+static inline u32 dcr_read_mmio(dcr_host_mmio_t host, unsigned int dcr_n)
 {
         return in_be32(host.token + ((host.base + dcr_n) * host.stride));
 }
 
-static inline void dcr_write(dcr_host_t host, unsigned int dcr_n, u32 value)
+static inline void dcr_write_mmio(dcr_host_mmio_t host,
+                                  unsigned int dcr_n,
+                                  u32 value)
 {
         out_be32(host.token + ((host.base + dcr_n) * host.stride), value);
 }
diff --git a/include/asm-powerpc/dcr-native.h b/include/asm-powerpc/dcr-native.h
index f8398ce80372..72d2b72c7390 100644
--- a/include/asm-powerpc/dcr-native.h
+++ b/include/asm-powerpc/dcr-native.h
@@ -26,14 +26,18 @@
 
 typedef struct {
         unsigned int base;
-} dcr_host_t;
+} dcr_host_native_t;
 
-#define DCR_MAP_OK(host)        (1)
+static inline bool dcr_map_ok_native(dcr_host_native_t host)
+{
+        return 1;
+}
 
-#define dcr_map(dev, dcr_n, dcr_c)      ((dcr_host_t){ .base = (dcr_n) })
-#define dcr_unmap(host, dcr_c)          do {} while (0)
-#define dcr_read(host, dcr_n)           mfdcr(dcr_n + host.base)
-#define dcr_write(host, dcr_n, value)   mtdcr(dcr_n + host.base, value)
+#define dcr_map_native(dev, dcr_n, dcr_c) \
+        ((dcr_host_native_t){ .base = (dcr_n) })
+#define dcr_unmap_native(host, dcr_c)           do {} while (0)
+#define dcr_read_native(host, dcr_n)            mfdcr(dcr_n + host.base)
+#define dcr_write_native(host, dcr_n, value)    mtdcr(dcr_n + host.base, value)
 
 /* Device Control Registers */
 void __mtdcr(int reg, unsigned int val);
diff --git a/include/asm-powerpc/dcr.h b/include/asm-powerpc/dcr.h
index 9338d50538f1..53b283050ab3 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 */