The Transmit Frame (XF) command is an alternative to using the TIC
register for transmitting. This command allows the guest to transmit the
contents of the transmit FIFO rather than a single character.
Signed-off-by: Jasper Lowell <jasper.low...@bt.com>
---
hw/char/escc2.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/hw/char/escc2.c b/hw/char/escc2.c
index 8198b7fec3..3bacdfaa7c 100644
--- a/hw/char/escc2.c
+++ b/hw/char/escc2.c
@@ -207,6 +207,14 @@
/* ISR1. */
#define REGISTER_ISR1_OFFSET 0x3b
+#define REGISTER_ISR1_BRK 0x80
+#define REGISTER_ISR1_BRKT 0x40
+#define REGISTER_ISR1_ALLS 0x20
+#define REGISTER_ISR1_XOFF 0x10
+#define REGISTER_ISR1_TIN 0x8
+#define REGISTER_ISR1_CSC 0x4
+#define REGISTER_ISR1_XON 0x2
+#define REGISTER_ISR1_XPR 0x1
/* IMR1. */
#define REGISTER_IMR1_OFFSET 0x3b
@@ -749,6 +757,7 @@ static uint64_t escc2_mem_read(void *opaque, hwaddr addr,
unsigned size)
static void escc2_channel_command(ESCC2ChannelState *channel)
{
+ unsigned int i;
uint8_t tmp, command;
command = REGISTER_READ(channel, REGISTER_CMDR);
@@ -766,6 +775,21 @@ static void escc2_channel_command(ESCC2ChannelState
*channel)
if (command & REGISTER_CMDR_RFRD) {
escc2_channel_irq_event(channel, REGISTER_ISR0, REGISTER_ISR0_TCD);
}
+
+ if (command & REGISTER_CMDR_XF) {
+ i = 0;
+ while (i < CHANNEL_FIFO_LENGTH && channel->fifo_transmit[i] != 0) {
+ i++;
+ }
+ qemu_chr_fe_write_all(&channel->chardev, channel->fifo_transmit, i);
+ escc2_channel_irq_event(channel, REGISTER_ISR1, REGISTER_ISR1_ALLS);
+
+ /*
+ * XFIFO is ready and ISR1_XPR should be generated. Fake the XRES
+ * command.
+ */
+ command &= REGISTER_CMDR_XRES;
+ }
}
static void escc2_mem_write(void *opaque, hwaddr addr, uint64_t value,
--
2.26.2
