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Commit f968ef34 authored by Daniel Thompson's avatar Daniel Thompson Committed by Greg Kroah-Hartman
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serial: imx: clean up imx_poll_put_char() 



imx_put_poll_char() has been simplified to remove the code to disable
interrupts. The present code can corrupt register state when re-entered
from FIQ handler.

Switch to _relaxed() MMIO functions (which are safe for polled I/O and
needed to avoid taking spin locks).

Signed-off-by: default avatarDaniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: default avatarDirk Behme <dirk.behme@de.bosch.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Huang Shijie <b32955@freescale.com>
Cc: linux-serial@vger.kernel.org
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 97f75471

drivers/tty/serial/imx.c

+5 −19
Original line number Diff line number Diff line
@@ -1457,42 +1457,28 @@ imx_verify_port(struct uart_port *port, struct serial_struct *ser) 
#if defined(CONFIG_CONSOLE_POLL)

static int imx_poll_get_char(struct uart_port *port)

{

	if (!(readl(port->membase + USR2) & USR2_RDR))

	if (!(readl_relaxed(port->membase + USR2) & USR2_RDR))

		return NO_POLL_CHAR;



	return readl(port->membase + URXD0) & URXD_RX_DATA;

	return readl_relaxed(port->membase + URXD0) & URXD_RX_DATA;

}



static void imx_poll_put_char(struct uart_port *port, unsigned char c)

{

	struct imx_port_ucrs old_ucr;

	unsigned int status;



	/* save control registers */

	imx_port_ucrs_save(port, &old_ucr);



	/* disable interrupts */

	writel(UCR1_UARTEN, port->membase + UCR1);

	writel(old_ucr.ucr2 & ~(UCR2_ATEN | UCR2_RTSEN | UCR2_ESCI),

	       port->membase + UCR2);

	writel(old_ucr.ucr3 & ~(UCR3_DCD | UCR3_RI | UCR3_DTREN),

	       port->membase + UCR3);



	/* drain */

	do {

		status = readl(port->membase + USR1);

		status = readl_relaxed(port->membase + USR1);

	} while (~status & USR1_TRDY);



	/* write */

	writel(c, port->membase + URTX0);

	writel_relaxed(c, port->membase + URTX0);



	/* flush */

	do {

		status = readl(port->membase + USR2);

		status = readl_relaxed(port->membase + USR2);

	} while (~status & USR2_TXDC);



	/* restore control registers */

	imx_port_ucrs_restore(port, &old_ucr);

}

#endif