From: Pekka Enberg <penberg@kernel.org>
Date: Mon, 10 Jan 2011 22:06:28 +0000 (+0200)
Subject: kvm,8250: Cleanup receive emulation
X-Git-Tag: next-20110824~3^2~521
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=e1b055120772a41f71addce3ba3d0400a7d0c17f;p=karo-tx-linux.git

kvm,8250: Cleanup receive emulation

This patch cleans up receive emulation by separating the stdin polling and
reading logic from the interrupt logic. The patch also fixes the interrupt
injection code to inject one type of interrupt at a time.

Signed-off-by: Pekka Enberg <penberg@kernel.org>
---

diff --git a/tools/kvm/8250-serial.c b/tools/kvm/8250-serial.c
index 16910e35dc16..8f66f4bfc039 100644
--- a/tools/kvm/8250-serial.c
+++ b/tools/kvm/8250-serial.c
@@ -13,7 +13,7 @@ struct serial8250_device {
 	uint16_t		iobase;
 	uint8_t			irq;
 
-	uint8_t			thr;
+	uint8_t			rbr;		/* receive buffer */
 	uint8_t			dll;
 	uint8_t			dlm;
 	uint8_t			iir;
@@ -71,6 +71,24 @@ static bool is_readable(int fd)
 	return poll(&pollfd, 1, 0) > 0;
 }
 
+static void serial8250__receive(struct kvm *self, struct serial8250_device *dev)
+{
+	int c;
+
+	if (dev->lsr & UART_LSR_DR)
+		return;
+
+	if (!is_readable(fileno(stdin)))
+		return;
+
+	c		= read_char(fileno(stdin));
+	if (c < 0)
+		return;
+
+	dev->rbr	= c;
+	dev->lsr	|= UART_LSR_DR;
+}
+
 /*
  * Interrupts are injected for ttyS0 only.
  */
@@ -85,24 +103,15 @@ void serial8250__interrupt(struct kvm *self)
 	if (!(dev->ier & (UART_IER_THRI|UART_IER_RDI)))
 		return;
 
+	serial8250__receive(self, dev);
+
 	new_iir		= 0;
 
-	/* We're always good for guest sending data. */
-	if (dev->ier & UART_IER_THRI)
+	if (dev->lsr & UART_LSR_DR)
+		new_iir			|= UART_IIR_RDI;
+	else if (dev->ier & UART_IER_THRI)
 		new_iir			|= UART_IIR_THRI;
 
-	/* Is there input in stdin to send to the guest? */
-	if (!(dev->lsr & UART_LSR_DR) && is_readable(fileno(stdin))) {
-		int c;
-
-		c			= read_char(fileno(stdin));
-		if (c >= 0) {
-			dev->thr		= c;
-			dev->lsr		|= UART_LSR_DR;
-			new_iir			|= UART_IIR_RDI;
-		}
-	}
-
 	/* Only send an IRQ if there's work to do. */
 	if (new_iir) {
 		dev->counter		= 0;
@@ -208,12 +217,12 @@ static bool serial8250_in(struct kvm *self, uint16_t port, void *data, int size,
 		return false;
 
 	switch (offset) {
-	case UART_TX:
+	case UART_RX:
 		if (dev->lsr & UART_LSR_DR) {
 			dev->iir		= UART_IIR_NO_INT;
 
 			dev->lsr		&= ~UART_LSR_DR;
-			ioport__write8(data, dev->thr);
+			ioport__write8(data, dev->rbr);
 		}
 		break;
 	case UART_IER: