serial: sirf: add serial loopback function support

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>

diff --git a/drivers/tty/serial/sirfsoc_uart.c b/drivers/tty/serial/sirfsoc_uart.c
index a500721..0e43799 100644 (file)
--- a/drivers/tty/serial/sirfsoc_uart.c
+++ b/drivers/tty/serial/sirfsoc_uart.c
@@ -108,6 +108,26 @@ static void sirfsoc_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
        unsigned int val = assert ? SIRFUART_AFC_CTRL_RX_THD : 0x0;
        unsigned int current_val;
 
+       if (mctrl & TIOCM_LOOP) {
+               if (sirfport->uart_reg->uart_type == SIRF_REAL_UART)
+                       wr_regl(port, ureg->sirfsoc_line_ctrl,
+                               rd_regl(port, ureg->sirfsoc_line_ctrl) |
+                               SIRFUART_LOOP_BACK);
+               else
+                       wr_regl(port, ureg->sirfsoc_mode1,
+                               rd_regl(port, ureg->sirfsoc_mode1) |
+                               SIRFSOC_USP_LOOP_BACK_CTRL);
+       } else {
+               if (sirfport->uart_reg->uart_type == SIRF_REAL_UART)
+                       wr_regl(port, ureg->sirfsoc_line_ctrl,
+                               rd_regl(port, ureg->sirfsoc_line_ctrl) &
+                               ~SIRFUART_LOOP_BACK);
+               else
+                       wr_regl(port, ureg->sirfsoc_mode1,
+                               rd_regl(port, ureg->sirfsoc_mode1) &
+                               ~SIRFSOC_USP_LOOP_BACK_CTRL);
+       }
+
        if (!sirfport->hw_flow_ctrl || !sirfport->ms_enabled)
                return;
        if (sirfport->uart_reg->uart_type == SIRF_REAL_UART) {

diff --git a/drivers/tty/serial/sirfsoc_uart.h b/drivers/tty/serial/sirfsoc_uart.h
index b49c23a..3ab3141 100644 (file)
--- a/drivers/tty/serial/sirfsoc_uart.h
+++ b/drivers/tty/serial/sirfsoc_uart.h
@@ -322,7 +322,7 @@ struct sirfsoc_uart_register sirfsoc_uart = {
 #define SIRFSOC_USP_RX_CLK_DIVISOR_OFFSET      24
 #define SIRFSOC_USP_ASYNC_DIV2_MASK            0x3f
 #define SIRFSOC_USP_ASYNC_DIV2_OFFSET          16
-
+#define SIRFSOC_USP_LOOP_BACK_CTRL             BIT(2)
 /* USP-UART Common */
 #define SIRFSOC_UART_RX_TIMEOUT(br, to)        (((br) * (((to) + 999) / 1000)) / 1000)
 #define SIRFUART_RECV_TIMEOUT_VALUE(x) \