[POWERPC] Uartlite: Add macros for register names

Add macros to define register names to improve readability.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>

arch/powerpc/boot/uartlite.c

@@ -16,30 +16,45 @@
 #include "io.h"
 #include "ops.h"
 
+#define ULITE_RX		0x00
+#define ULITE_TX		0x04
+#define ULITE_STATUS		0x08
+#define ULITE_CONTROL		0x0c
+
+#define ULITE_STATUS_RXVALID	0x01
+#define ULITE_STATUS_TXFULL	0x08
+
+#define ULITE_CONTROL_RST_RX	0x02
+
 static void * reg_base;
 
 static int uartlite_open(void)
 {
 	/* Clear the RX FIFO */
-	out_be32(reg_base + 0x0C, 0x2);
+	out_be32(reg_base + ULITE_CONTROL, ULITE_CONTROL_RST_RX);
 	return 0;
 }
 
 static void uartlite_putc(unsigned char c)
 {
-	while ((in_be32(reg_base + 0x8) & 0x08) != 0); /* spin */
-	out_be32(reg_base + 0x4, c);
+	u32 reg = ULITE_STATUS_TXFULL;
+	while (reg & ULITE_STATUS_TXFULL) /* spin on TXFULL bit */
+		reg = in_be32(reg_base + ULITE_STATUS);
+	out_be32(reg_base + ULITE_TX, c);
 }
 
 static unsigned char uartlite_getc(void)
 {
-	while ((in_be32(reg_base + 0x8) & 0x01) == 0); /* spin */
-	return in_be32(reg_base);
+	u32 reg = ULITE_STATUS_RXVALID;
+	while (reg & ULITE_STATUS_RXVALID) /* spin on RXVALID bit */
+		reg = in_be32(reg_base + ULITE_STATUS);
+	return in_be32(reg_base + ULITE_RX);
 }
 
 static u8 uartlite_tstc(void)
 {
-	return ((in_be32(reg_base + 0x8) & 0x01) != 0);
+	u32 reg = in_be32(reg_base + ULITE_STATUS);
+	return reg & ULITE_STATUS_RXVALID;
 }
 
 int uartlite_console_init(void *devp, struct serial_console_data *scdp)