@@ -54,6 +54,11 @@
#define INT_E (INT_OE | INT_BE | INT_PE | INT_FE)
#define INT_MS (INT_RI | INT_DSR | INT_DCD | INT_CTS)
+/* UARTCR bits */
+#define PL011_CR_UARTEN (1 << 0)
+#define PL011_CR_TXE (1 << 8)
+#define PL011_CR_RXE (1 << 9)
+
static const unsigned char pl011_id_arm[8] =
{ 0x11, 0x10, 0x14, 0x00, 0x0d, 0xf0, 0x05, 0xb1 };
static const unsigned char pl011_id_luminary[8] =
@@ -203,6 +208,11 @@ static void pl011_trace_baudrate_change(const PL011State *s)
s->ibrd, s->fbrd);
}
+static inline bool pl011_can_transmit(PL011State *s)
+{
+ return s->cr & PL011_CR_UARTEN && s->cr & PL011_CR_TXE;
+}
+
static void pl011_write(void *opaque, hwaddr offset,
uint64_t value, unsigned size)
{
@@ -213,7 +223,9 @@ static void pl011_write(void *opaque, hwaddr offset,
switch (offset >> 2) {
case 0: /* UARTDR */
- /* ??? Check if transmitter is enabled. */
+ if (!pl011_can_transmit(s)) {
+ break;
+ }
ch = value;
/* XXX this blocks entire thread. Rewrite to use
* qemu_chr_fe_write and background I/O callbacks */
@@ -284,7 +296,11 @@ static int pl011_can_receive(void *opaque)
PL011State *s = (PL011State *)opaque;
int r;
- r = s->read_count < pl011_get_fifo_depth(s);
+ if (!(s->cr & PL011_CR_UARTEN) || !(s->cr & PL011_CR_RXE)) {
+ r = 0;
+ } else {
+ r = s->read_count < pl011_get_fifo_depth(s);
+ }
trace_pl011_can_receive(s->lcr, s->read_count, r);
return r;
}
@@ -429,7 +445,7 @@ static void pl011_reset(DeviceState *dev)
s->fbrd = 0;
s->read_trigger = 1;
s->ifl = 0x12;
- s->cr = 0x300;
+ s->cr = PL011_CR_RXE | PL011_CR_TXE;
pl011_reset_pipe(s);
for (i = 0; i < ARRAY_SIZE(s->irq); i++) {
UART should be enabled in general and have RX enabled specifically to be able to receive data from peripheral device. Same goes for transmitting data to peripheral device and a TXE flag. Check if UART CR register has EN and RXE or TXE bits enabled before trying to receive or transmit data. Signed-off-by: Evgeny Iakovlev <eiakovlev@linux.microsoft.com> --- hw/char/pl011.c | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-)