diff options
| -rw-r--r-- | hw/serial.c | 28 |
1 files changed, 20 insertions, 8 deletions
diff --git a/hw/serial.c b/hw/serial.c index e7538ac8ca..df67383d06 100644 --- a/hw/serial.c +++ b/hw/serial.c @@ -169,11 +169,19 @@ static int fifo_put(SerialState *s, int fifo, uint8_t chr) { SerialFIFO *f = (fifo) ? &s->recv_fifo : &s->xmit_fifo; - f->data[f->head++] = chr; + /* Receive overruns do not overwrite FIFO contents. */ + if (fifo == XMIT_FIFO || f->count < UART_FIFO_LENGTH) { - if (f->head == UART_FIFO_LENGTH) - f->head = 0; - f->count++; + f->data[f->head++] = chr; + + if (f->head == UART_FIFO_LENGTH) + f->head = 0; + } + + if (f->count < UART_FIFO_LENGTH) + f->count++; + else if (fifo == RECV_FIFO) + s->lsr |= UART_LSR_OE; return 1; } @@ -533,8 +541,10 @@ static uint32_t serial_ioport_read(void *opaque, uint32_t addr) break; case 2: ret = s->iir; + if (ret & UART_IIR_THRI) { s->thr_ipending = 0; - serial_update_irq(s); + serial_update_irq(s); + } break; case 3: ret = s->lcr; @@ -544,9 +554,9 @@ static uint32_t serial_ioport_read(void *opaque, uint32_t addr) break; case 5: ret = s->lsr; - /* Clear break interrupt */ - if (s->lsr & UART_LSR_BI) { - s->lsr &= ~UART_LSR_BI; + /* Clear break and overrun interrupts */ + if (s->lsr & (UART_LSR_BI|UART_LSR_OE)) { + s->lsr &= ~(UART_LSR_BI|UART_LSR_OE); serial_update_irq(s); } break; @@ -629,6 +639,8 @@ static void serial_receive1(void *opaque, const uint8_t *buf, int size) /* call the timeout receive callback in 4 char transmit time */ qemu_mod_timer(s->fifo_timeout_timer, qemu_get_clock (vm_clock) + s->char_transmit_time * 4); } else { + if (s->lsr & UART_LSR_DR) + s->lsr |= UART_LSR_OE; s->rbr = buf[0]; s->lsr |= UART_LSR_DR; } |