Upgrade to 4.4.50-rt62

[kvmfornfv.git] / kernel / drivers / tty / serial / atmel_serial.c

diff --git a/kernel/drivers/tty/serial/atmel_serial.c b/kernel/drivers/tty/serial/atmel_serial.c
index 9429455..a0f9116 100644 (file)
--- a/kernel/drivers/tty/serial/atmel_serial.c
+++ b/kernel/drivers/tty/serial/atmel_serial.c
@@ -277,6 +277,13 @@ static bool atmel_use_dma_rx(struct uart_port *port)
        return atmel_port->use_dma_rx;
 }
 
+static bool atmel_use_fifo(struct uart_port *port)
+{
+       struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+
+       return atmel_port->fifo_size;
+}
+
 static unsigned int atmel_get_lines_status(struct uart_port *port)
 {
        struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
@@ -463,6 +470,14 @@ static void atmel_stop_tx(struct uart_port *port)
                /* disable PDC transmit */
                atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTDIS);
        }
+
+       /*
+        * Disable the transmitter.
+        * This is mandatory when DMA is used, otherwise the DMA buffer
+        * is fully transmitted.
+        */
+       atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXDIS);
+
        /* Disable interrupts */
        atmel_uart_writel(port, ATMEL_US_IDR, atmel_port->tx_done_mask);
 
@@ -478,21 +493,26 @@ static void atmel_start_tx(struct uart_port *port)
 {
        struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 
-       if (atmel_use_pdc_tx(port)) {
-               if (atmel_uart_readl(port, ATMEL_PDC_PTSR) & ATMEL_PDC_TXTEN)
-                       /* The transmitter is already running.  Yes, we
-                          really need this.*/
-                       return;
+       if (atmel_use_pdc_tx(port) && (atmel_uart_readl(port, ATMEL_PDC_PTSR)
+                                      & ATMEL_PDC_TXTEN))
+               /* The transmitter is already running.  Yes, we
+                  really need this.*/
+               return;
 
+       if (atmel_use_pdc_tx(port) || atmel_use_dma_tx(port))
                if ((port->rs485.flags & SER_RS485_ENABLED) &&
                    !(port->rs485.flags & SER_RS485_RX_DURING_TX))
                        atmel_stop_rx(port);
 
+       if (atmel_use_pdc_tx(port))
                /* re-enable PDC transmit */
                atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTEN);
-       }
+
        /* Enable interrupts */
        atmel_uart_writel(port, ATMEL_US_IER, atmel_port->tx_done_mask);
+
+       /* re-enable the transmitter */
+       atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN);
 }
 
 /*
@@ -2066,6 +2086,7 @@ static void atmel_serial_pm(struct uart_port *port, unsigned int state,
 static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
                              struct ktermios *old)
 {
+       struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
        unsigned long flags;
        unsigned int old_mode, mode, imr, quot, baud;
 
@@ -2169,7 +2190,30 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
                mode |= ATMEL_US_USMODE_RS485;
        } else if (termios->c_cflag & CRTSCTS) {
                /* RS232 with hardware handshake (RTS/CTS) */
-               mode |= ATMEL_US_USMODE_HWHS;
+               if (atmel_use_fifo(port) &&
+                   !mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_CTS)) {
+                       /*
+                        * with ATMEL_US_USMODE_HWHS set, the controller will
+                        * be able to drive the RTS pin high/low when the RX
+                        * FIFO is above RXFTHRES/below RXFTHRES2.
+                        * It will also disable the transmitter when the CTS
+                        * pin is high.
+                        * This mode is not activated if CTS pin is a GPIO
+                        * because in this case, the transmitter is always
+                        * disabled (there must be an internal pull-up
+                        * responsible for this behaviour).
+                        * If the RTS pin is a GPIO, the controller won't be
+                        * able to drive it according to the FIFO thresholds,
+                        * but it will be handled by the driver.
+                        */
+                       mode |= ATMEL_US_USMODE_HWHS;
+               } else {
+                       /*
+                        * For platforms without FIFO, the flow control is
+                        * handled by the driver.
+                        */
+                       mode |= ATMEL_US_USMODE_NORMAL;
+               }
        } else {
                /* RS232 without hadware handshake */
                mode |= ATMEL_US_USMODE_NORMAL;