diff --git a/src/uart.c b/src/uart.c
index f83bf2a9..3128888b 100644
--- a/src/uart.c
+++ b/src/uart.c
@@ -22,7 +22,7 @@ void uart_init(void)
 
 void uart_putbyte(u8 c)
 {
-    while (!(read32(UART_BASE + UTRSTAT) & 0x02))
+    while (!(read32(UART_BASE + UTRSTAT) & UTRSTAT_TXBE))
         ;
 
     write32(UART_BASE + UTXH, c);
@@ -30,7 +30,7 @@ void uart_putbyte(u8 c)
 
 u8 uart_getbyte(void)
 {
-    while (!(read32(UART_BASE + UTRSTAT) & 0x01))
+    while (!(read32(UART_BASE + UTRSTAT) & UTRSTAT_RXD))
         ;
 
     return read32(UART_BASE + URXH);
@@ -86,7 +86,7 @@ void uart_setbaud(int baudrate)
 
 void uart_flush(void)
 {
-    while (!(read32(UART_BASE + UTRSTAT) & 0x04))
+    while (!(read32(UART_BASE + UTRSTAT) & UTRSTAT_TXE))
         ;
 }
 
@@ -114,7 +114,7 @@ static bool uart_iodev_can_write(void *opaque)
 static ssize_t uart_iodev_can_read(void *opaque)
 {
     UNUSED(opaque);
-    return read32(UART_BASE + UTRSTAT) & 0x01;
+    return read32(UART_BASE + UTRSTAT) & UTRSTAT_RXD;
 }
 
 static ssize_t uart_iodev_read(void *opaque, void *buf, size_t len)
diff --git a/src/uart_regs.h b/src/uart_regs.h
index 1b244413..bca1fe42 100644
--- a/src/uart_regs.h
+++ b/src/uart_regs.h
@@ -4,7 +4,29 @@
 #define UCON     0x004
 #define UFCON    0x008
 #define UTRSTAT  0x010
+#define UFSTAT   0x018
 #define UTXH     0x020
 #define URXH     0x024
 #define UBRDIV   0x028
 #define UFRACVAL 0x02c
+
+#define UCON_TXTHRESH_ENA BIT(13)
+#define UCON_RXTHRESH_ENA BIT(12)
+#define UCON_RXTO_ENA     BIT(9)
+#define UCON_TXMODE       GENMASK(3, 2)
+#define UCON_RXMODE       GENMASK(1, 0)
+
+#define UCON_MODE_OFF 0
+#define UCON_MODE_IRQ 1
+
+#define UTRSTAT_RXTO     BIT(9)
+#define UTRSTAT_TXTHRESH BIT(5)
+#define UTRSTAT_RXTHRESH BIT(4)
+#define UTRSTAT_TXE      BIT(2)
+#define UTRSTAT_TXBE     BIT(1)
+#define UTRSTAT_RXD      BIT(0)
+
+#define UFSTAT_TXFULL BIT(9)
+#define UFSTAT_RXFULL BIT(8)
+#define UFSTAT_TXCNT  GENMASK(7, 4)
+#define UFSTAT_RXCNT  GENMASK(3, 0)