Merge branch 'linux-omap-pm-3.0' into linux-omap-3.0

1 files changed, 49 insertions, 0 deletions

diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index 47cadf4..0275c28 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -1335,6 +1335,55 @@ static struct platform_driver serial_omap_driver = {
 	},
 };
 
+int omap_uart_active(int num, u32 timeout)
+{
+	struct uart_omap_port *up = ui[num];
+	struct circ_buf *xmit;
+	unsigned int status;
+
+	if(num >= OMAP_MAX_HSUART_PORTS)
+		return 0;
+
+	/* Though when UART's initialised this can never happen,
+	 * but during initialisation, it can happen the "ui"
+	 * structure is not initialized and the timer kicks
+	 * in. This would result in a NULL value, resulting
+	 * in crash.
+	 */
+	up = ui[num];
+	if (up == NULL)
+		return 0;
+
+	if (!up->port_activity)
+		return 1;
+
+	/* Check for recent driver activity. If time delta from now
+	 * to last activty < "uart idle timeout" second keep clocks on.
+	 */
+	if (((jiffies - up->port_activity) < timeout))
+		return 1;
+
+	xmit = &up->port.state->xmit;
+	if (!(uart_circ_empty(xmit) || uart_tx_stopped(&up->port)))
+		return 1;
+
+	status = serial_in(up, UART_LSR);
+	/* TX hardware not empty */
+	if (!(status & (UART_LSR_TEMT | UART_LSR_THRE)))
+		return 1;
+
+	/* Any rx activity? */
+	if (status & UART_LSR_DR)
+		return 1;
+
+	/* Check if DMA channels are active */
+	if (up->use_dma && (up->uart_dma.rx_dma_channel != OMAP_UART_DMA_CH_FREE ||
+		up->uart_dma.tx_dma_channel != OMAP_UART_DMA_CH_FREE))
+		return 1;
+	return 0;
+}
+EXPORT_SYMBOL(omap_uart_active);
+
 static int __init serial_omap_init(void)
 {
 	int ret;