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Commit 9bc19af9 authored by Andrey Smirnov's avatar Andrey Smirnov Committed by Greg Kroah-Hartman
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tty: serial: fsl_lpuart: Flush HW FIFOs in .flush_buffer 



Switching baud rate might cause bogus data to appear in HW
FIFO. Add code to do a HW FIFO flush to .flush_buffer callback to
avoid that.

Signed-off-by: default avatarFugang Duan <fugang.duan@nxp.com>
Signed-off-by: default avatarAndrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-4-andrew.smirnov@gmail.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent cc584ab8

drivers/tty/serial/fsl_lpuart.c

+17 −6
Original line number Diff line number Diff line
@@ -518,9 +518,16 @@ static int lpuart_dma_tx_request(struct uart_port *port) 
	return 0;

}



static bool lpuart_is_32(struct lpuart_port *sport)

{

	return sport->port.iotype == UPIO_MEM32 ||

	       sport->port.iotype ==  UPIO_MEM32BE;

}



static void lpuart_flush_buffer(struct uart_port *port)

{

	struct lpuart_port *sport = container_of(port, struct lpuart_port, port);

	u32 val;



	if (sport->lpuart_dma_tx_use) {

		if (sport->dma_tx_in_progress) {
@@ -530,6 +537,16 @@ static void lpuart_flush_buffer(struct uart_port *port) 
		}

		dmaengine_terminate_all(sport->dma_tx_chan);

	}



	if (lpuart_is_32(sport)) {

		val = lpuart32_read(&sport->port, UARTFIFO);

		val |= UARTFIFO_TXFLUSH | UARTFIFO_RXFLUSH;

		lpuart32_write(&sport->port, val, UARTFIFO);

	} else {

		val = readb(sport->port.membase + UARTPFIFO);

		val |= UARTCFIFO_TXFLUSH | UARTCFIFO_RXFLUSH;

		writeb(val, sport->port.membase + UARTCFIFO);

	}

}



#if defined(CONFIG_CONSOLE_POLL)
@@ -754,12 +771,6 @@ static unsigned int lpuart32_tx_empty(struct uart_port *port) 
	return 0;

}



static bool lpuart_is_32(struct lpuart_port *sport)

{

	return sport->port.iotype == UPIO_MEM32 ||

	       sport->port.iotype ==  UPIO_MEM32BE;

}



static irqreturn_t lpuart_txint(int irq, void *dev_id)

{

	struct lpuart_port *sport = dev_id;