hw/char/pl011: Replace magic values by register field definitions

0x400 is Data Register Break Error (DR_BE),
0x10 is Line Control Register Fifo Enabled (LCR_FEN)
and 0x1 is Send Break (LCR_BRK).

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230522153144.30610-7-philmd@linaro.org>

hw/char/pl011.c

@@ -54,6 +54,9 @@ DeviceState *pl011_create(hwaddr addr, qemu_irq irq, Chardev *chr)
 #define PL011_FLAG_TXFF 0x20
 #define PL011_FLAG_RXFE 0x10
 
+/* Data Register, UARTDR */
+#define DR_BE   (1 << 10)
+
 /* Interrupt status bits in UARTRIS, UARTMIS, UARTIMSC */
 #define INT_OE (1 << 10)
 #define INT_BE (1 << 9)
@@ -69,6 +72,10 @@ DeviceState *pl011_create(hwaddr addr, qemu_irq irq, Chardev *chr)
 #define INT_E (INT_OE | INT_BE | INT_PE | INT_FE)
 #define INT_MS (INT_RI | INT_DSR | INT_DCD | INT_CTS)
 
+/* Line Control Register, UARTLCR_H */
+#define LCR_FEN     (1 << 4)
+#define LCR_BRK     (1 << 0)
+
 static const unsigned char pl011_id_arm[8] =
   { 0x11, 0x10, 0x14, 0x00, 0x0d, 0xf0, 0x05, 0xb1 };
 static const unsigned char pl011_id_luminary[8] =
@@ -116,7 +123,7 @@ static void pl011_update(PL011State *s)
 
 static bool pl011_is_fifo_enabled(PL011State *s)
 {
-    return (s->lcr & 0x10) != 0;
+    return (s->lcr & LCR_FEN) != 0;
 }
 
 static inline unsigned pl011_get_fifo_depth(PL011State *s)
@@ -218,7 +225,7 @@ static void pl011_set_read_trigger(PL011State *s)
        the threshold.  However linux only reads the FIFO in response to an
        interrupt.  Triggering the interrupt when the FIFO is non-empty seems
        to make things work.  */
-    if (s->lcr & 0x10)
+    if (s->lcr & LCR_FEN)
         s->read_trigger = (s->ifl >> 1) & 0x1c;
     else
 #endif
@@ -281,11 +288,11 @@ static void pl011_write(void *opaque, hwaddr offset,
         break;
     case 11: /* UARTLCR_H */
         /* Reset the FIFO state on FIFO enable or disable */
-        if ((s->lcr ^ value) & 0x10) {
+        if ((s->lcr ^ value) & LCR_FEN) {
             pl011_reset_fifo(s);
         }
-        if ((s->lcr ^ value) & 0x1) {
-            int break_enable = value & 0x1;
+        if ((s->lcr ^ value) & LCR_BRK) {
+            int break_enable = value & LCR_BRK;
             qemu_chr_fe_ioctl(&s->chr, CHR_IOCTL_SERIAL_SET_BREAK,
                               &break_enable);
         }
@@ -359,8 +366,9 @@ static void pl011_receive(void *opaque, const uint8_t *buf, int size)
 
 static void pl011_event(void *opaque, QEMUChrEvent event)
 {
-    if (event == CHR_EVENT_BREAK)
-        pl011_put_fifo(opaque, 0x400);
+    if (event == CHR_EVENT_BREAK) {
+        pl011_put_fifo(opaque, DR_BE);
+    }
 }
 
 static void pl011_clock_update(void *opaque, ClockEvent event)