serial: at91: make UART support dma and pdc transfers

Because the UART lack of receive timeout register, so we use a timer to trigger
data receive.
The DBGU is regarded as UART.

Signed-off-by: Elen Song <elen.song@atmel.com>
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 42 insertions, 6 deletions

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 8dbc3e67dfa4..7e2cb31497c3 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -40,6 +40,7 @@
 #include <linux/atmel_serial.h>
 #include <linux/uaccess.h>
 #include <linux/platform_data/atmel.h>
+#include <linux/timer.h>
 
 #include <asm/io.h>
 #include <asm/ioctls.h>
@@ -168,6 +169,7 @@ struct atmel_uart_port {
         struct serial_rs485     rs485;          /* rs485 settings */
         unsigned int            tx_done_mask;
         bool                    is_usart;       /* usart or uart */
+        struct timer_list       uart_timer;     /* uart timer */
         int (*prepare_rx)(struct uart_port *port);
         int (*prepare_tx)(struct uart_port *port);
         void (*schedule_rx)(struct uart_port *port);
@@ -822,6 +824,9 @@ static void atmel_release_rx_dma(struct uart_port *port)
         atmel_port->desc_rx = NULL;
         atmel_port->chan_rx = NULL;
         atmel_port->cookie_rx = -EINVAL;
+
+        if (!atmel_port->is_usart)
+                del_timer_sync(&atmel_port->uart_timer);
 }
 
 static void atmel_rx_from_dma(struct uart_port *port)
@@ -951,6 +956,15 @@ chan_err:
         return -EINVAL;
 }
 
+static void atmel_uart_timer_callback(unsigned long data)
+{
+        struct uart_port *port = (void *)data;
+        struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+
+        tasklet_schedule(&atmel_port->tasklet);
+        mod_timer(&atmel_port->uart_timer, jiffies + uart_poll_timeout(port));
+}
+
 /*
  * receive interrupt handler.
  */
@@ -1214,6 +1228,9 @@ static void atmel_release_rx_pdc(struct uart_port *port)
                                  DMA_FROM_DEVICE);
                 kfree(pdc->buf);
         }
+
+        if (!atmel_port->is_usart)
+                del_timer_sync(&atmel_port->uart_timer);
 }
 
 static void atmel_rx_from_pdc(struct uart_port *port)
@@ -1575,17 +1592,36 @@ static int atmel_startup(struct uart_port *port)
 
         if (atmel_use_pdc_rx(port)) {
                 /* set UART timeout */
-                UART_PUT_RTOR(port, PDC_RX_TIMEOUT);
-                UART_PUT_CR(port, ATMEL_US_STTTO);
+                if (!atmel_port->is_usart) {
+                        setup_timer(&atmel_port->uart_timer,
+                                        atmel_uart_timer_callback,
+                                        (unsigned long)port);
+                        mod_timer(&atmel_port->uart_timer,
+                                        jiffies + uart_poll_timeout(port));
+                /* set USART timeout */
+                } else {
+                        UART_PUT_RTOR(port, PDC_RX_TIMEOUT);
+                        UART_PUT_CR(port, ATMEL_US_STTTO);
 
-                UART_PUT_IER(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT);
+                        UART_PUT_IER(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT);
+                }
                 /* enable PDC controller */
                 UART_PUT_PTCR(port, ATMEL_PDC_RXTEN);
         } else if (atmel_use_dma_rx(port)) {
-                UART_PUT_RTOR(port, PDC_RX_TIMEOUT);
-                UART_PUT_CR(port, ATMEL_US_STTTO);
+                /* set UART timeout */
+                if (!atmel_port->is_usart) {
+                        setup_timer(&atmel_port->uart_timer,
+                                        atmel_uart_timer_callback,
+                                        (unsigned long)port);
+                        mod_timer(&atmel_port->uart_timer,
+                                        jiffies + uart_poll_timeout(port));
+                /* set USART timeout */
+                } else {
+                        UART_PUT_RTOR(port, PDC_RX_TIMEOUT);
+                        UART_PUT_CR(port, ATMEL_US_STTTO);
 
-                UART_PUT_IER(port, ATMEL_US_TIMEOUT);
+                        UART_PUT_IER(port, ATMEL_US_TIMEOUT);
+                }
         } else {
                 /* enable receive only */
                 UART_PUT_IER(port, ATMEL_US_RXRDY);