[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, 13 insertions, 7 deletions

diff --git a/include/asm-powerpc/dcr-mmio.h b/include/asm-powerpc/dcr-mmio.h
index 08532ff1899..acd491dbd45 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);
 }