smc911x: add 16 bit support

Signed-off-by: Jens Gehrlein <sew_s@tqs.de>
Signed-off-by: Ben Warren <biggerbadderben@gmail.com>

README

@@ -786,6 +786,21 @@ The following options need to be configured:
 			Define this to use i/o functions instead of macros
 			(some hardware wont work with macros)
 
+		CONFIG_DRIVER_SMC911X
+		Support for SMSC's LAN911x and LAN921x chips
+
+			CONFIG_DRIVER_SMC911X_BASE
+			Define this to hold the physical address
+			of the device (I/O space)
+
+			CONFIG_DRIVER_SMC911X_32_BIT
+			Define this if data bus is 32 bits
+
+			CONFIG_DRIVER_SMC911X_16_BIT
+			Define this if data bus is 16 bits. If your processor
+			automatically converts one 32 bit word to two 16 bit
+			words you may also try CONFIG_DRIVER_SMC911X_32_BIT.
+
 - USB Support:
 		At the moment only the UHCI host controller is
 		supported (PIP405, MIP405, MPC5200); define

drivers/net/smc911x.c

@@ -30,6 +30,12 @@
 #include <net.h>
 #include <miiphy.h>
 
+#if defined (CONFIG_DRIVER_SMC911X_32_BIT) && \
+	defined (CONFIG_DRIVER_SMC911X_16_BIT)
+#error "SMC911X: Only one of CONFIG_DRIVER_SMC911X_32_BIT and \
+	CONFIG_DRIVER_SMC911X_16_BIT shall be set"
+#endif
+
 #ifdef CONFIG_DRIVER_SMC911X_32_BIT
 static inline u32 reg_read(u32 addr)
 {
@@ -39,9 +45,20 @@ static inline void reg_write(u32 addr, u32 val)
 {
 	*(volatile u32*)addr = val;
 }
+#elif CONFIG_DRIVER_SMC911X_16_BIT
+static inline u32 reg_read(u32 addr)
+{
+	volatile u16 *addr_16 = (u16 *)addr;
+	return ((*addr_16 & 0x0000ffff) | (*(addr_16 + 1) << 16));
+}
+static inline void reg_write(u32 addr, u32 val)
+{
+	*(volatile u16*)addr = (u16)val;
+	*(volatile u16*)(addr + 2) = (u16)(val >> 16);
+}
 #else
-#error "SMC911X: Only 32-bit bus is supported"
-#endif
+#error "SMC911X: undefined bus width"
+#endif /* CONFIG_DRIVER_SMC911X_16_BIT */
 
 #define mdelay(n)       udelay((n)*1000)