hw/net/lan9118: Add symbolic constants for register offsets

The lan9118 code mostly uses symbolic constants for register offsets;
the exceptions are those which the datasheet doesn't give an official
symbolic name to.

Add some names for the registers which don't already have them, based
on the longer names they are given in the memory map.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20210108180401.2263-3-peter.maydell@linaro.org

hw/net/lan9118.c

@@ -40,6 +40,17 @@ do { hw_error("lan9118: error: " fmt , ## __VA_ARGS__);} while (0)
 do { fprintf(stderr, "lan9118: error: " fmt , ## __VA_ARGS__);} while (0)
 #endif
 
+/* The tx and rx fifo ports are a range of aliased 32-bit registers */
+#define RX_DATA_FIFO_PORT_FIRST 0x00
+#define RX_DATA_FIFO_PORT_LAST 0x1f
+#define TX_DATA_FIFO_PORT_FIRST 0x20
+#define TX_DATA_FIFO_PORT_LAST 0x3f
+
+#define RX_STATUS_FIFO_PORT 0x40
+#define RX_STATUS_FIFO_PEEK 0x44
+#define TX_STATUS_FIFO_PORT 0x48
+#define TX_STATUS_FIFO_PEEK 0x4c
+
 #define CSR_ID_REV      0x50
 #define CSR_IRQ_CFG     0x54
 #define CSR_INT_STS     0x58
@@ -1020,7 +1031,8 @@ static void lan9118_writel(void *opaque, hwaddr offset,
     offset &= 0xff;
 
     //DPRINTF("Write reg 0x%02x = 0x%08x\n", (int)offset, val);
-    if (offset >= 0x20 && offset < 0x40) {
+    if (offset >= TX_DATA_FIFO_PORT_FIRST &&
+        offset <= TX_DATA_FIFO_PORT_LAST) {
         /* TX FIFO */
         tx_fifo_push(s, val);
         return;
@@ -1198,18 +1210,18 @@ static uint64_t lan9118_readl(void *opaque, hwaddr offset,
     lan9118_state *s = (lan9118_state *)opaque;
 
     //DPRINTF("Read reg 0x%02x\n", (int)offset);
-    if (offset < 0x20) {
+    if (offset <= RX_DATA_FIFO_PORT_LAST) {
         /* RX FIFO */
         return rx_fifo_pop(s);
     }
     switch (offset) {
-    case 0x40:
+    case RX_STATUS_FIFO_PORT:
         return rx_status_fifo_pop(s);
-    case 0x44:
+    case RX_STATUS_FIFO_PEEK:
         return s->rx_status_fifo[s->rx_status_fifo_head];
-    case 0x48:
+    case TX_STATUS_FIFO_PORT:
         return tx_status_fifo_pop(s);
-    case 0x4c:
+    case TX_STATUS_FIFO_PEEK:
         return s->tx_status_fifo[s->tx_status_fifo_head];
     case CSR_ID_REV:
         return 0x01180001;