diff mbox

[PULL,41/47] serial: update LSR on enabling/disabling FIFOs

Message ID 1418661511-22348-42-git-send-email-pbonzini@redhat.com
State New
Headers show

Commit Message

Paolo Bonzini Dec. 15, 2014, 4:38 p.m. UTC 
When the transmit FIFO is emptied or enabled, the transmitter
hold register is empty.  When it is disabled, it is also emptied and
in addition the previous contents of the transmitter hold register
are discarded.  In either case, the THRE bit in LSR must be set and
THRI raised.

When the receive FIFO is emptied or enabled, the data ready and break
bits must be cleared in LSR.  Likewise when the receive FIFO is disabled.

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/char/serial.c | 3 +++
 1 file changed, 3 insertions(+)
diff mbox

Patch

diff --git a/hw/char/serial.c b/hw/char/serial.c
index 9adb126..76054a5 100644
--- a/hw/char/serial.c
+++ b/hw/char/serial.c
@@ -377,12 +377,15 @@  static void serial_ioport_write(void *opaque, hwaddr addr, uint64_t val,
         /* FIFO clear */
 
         if (val & UART_FCR_RFR) {
+            s->lsr &= ~(UART_LSR_DR | UART_LSR_BI);
             timer_del(s->fifo_timeout_timer);
             s->timeout_ipending = 0;
             fifo8_reset(&s->recv_fifo);
         }
 
         if (val & UART_FCR_XFR) {
+            s->lsr |= UART_LSR_THRE;
+            s->thr_ipending = 1;
             fifo8_reset(&s->xmit_fifo);
         }