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Commit 2e68c22f authored by Elen Song's avatar Elen Song Committed by Greg Kroah-Hartman
Browse files

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: default avatarElen Song <elen.song@atmel.com>
Signed-off-by: default avatarLudovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 055560b0

drivers/tty/serial/atmel_serial.c

+42 −6
Original line number Diff line number Diff line
@@ -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 @@ static int atmel_prepare_rx_dma(struct uart_port *port) 
	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 */

		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);

		}

		/* enable PDC controller */

		UART_PUT_PTCR(port, ATMEL_PDC_RXTEN);

	} else if (atmel_use_dma_rx(port)) {

		/* 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);

		}

	} else {

		/* enable receive only */

		UART_PUT_IER(port, ATMEL_US_RXRDY);