serial: sirf: correct condition for fetching dma buffer into tty

In rx dma-callback it calls tasklet_schedule, if the tasklet
be scheduled after all the dma-callback in the rx dma channel,
current check condition in the tasklet will not do fetch dma
buffer into tty because tx_issued is equal with tx_completed,
so as timeout tasklet does.

so we check whether we should fetch the whole dma buffer into
tty according to the status of transactions in rx dma channel.

Signed-off-by: Qipan Li <Qipan.Li@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/sirfsoc_uart.c

@@ -524,9 +524,11 @@ static void sirfsoc_rx_tmo_process_tl(unsigned long param)
 	struct sirfsoc_int_status *uint_st = &sirfport->uart_reg->uart_int_st;
 	unsigned int count;
 	unsigned long flags;
+	struct dma_tx_state tx_state;
 
 	spin_lock_irqsave(&sirfport->rx_lock, flags);
-	while (sirfport->rx_completed != sirfport->rx_issued) {
+	while (DMA_COMPLETE == dmaengine_tx_status(sirfport->rx_dma_chan,
+		sirfport->rx_dma_items[sirfport->rx_completed].cookie, &tx_state)) {
 		sirfsoc_uart_insert_rx_buf_to_tty(sirfport,
 					SIRFSOC_RX_DMA_BUF_SIZE);
 		sirfport->rx_completed++;
@@ -709,8 +711,10 @@ static void sirfsoc_uart_rx_dma_complete_tl(unsigned long param)
 	struct sirfsoc_register *ureg = &sirfport->uart_reg->uart_reg;
 	struct sirfsoc_int_en *uint_en = &sirfport->uart_reg->uart_int_en;
 	unsigned long flags;
+	struct dma_tx_state tx_state;
 	spin_lock_irqsave(&sirfport->rx_lock, flags);
-	while (sirfport->rx_completed != sirfport->rx_issued) {
+	while (DMA_COMPLETE == dmaengine_tx_status(sirfport->rx_dma_chan,
+			sirfport->rx_dma_items[sirfport->rx_completed].cookie, &tx_state)) {
 		sirfsoc_uart_insert_rx_buf_to_tty(sirfport,
 					SIRFSOC_RX_DMA_BUF_SIZE);
 		if (rd_regl(port, ureg->sirfsoc_int_en_reg) &