From f968ef34945f8e606c5d98ff330a5903785ea76a Mon Sep 17 00:00:00 2001 From: Daniel Thompson Date: Tue, 28 Oct 2014 09:28:07 +0100 Subject: [PATCH] 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: Daniel Thompson Signed-off-by: Dirk Behme Cc: Jiri Slaby Cc: Huang Shijie Cc: linux-serial@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/imx.c | 24 +++++------------------- 1 file changed, 5 insertions(+), 19 deletions(-) diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index d2e6cf5a1ab8..8d61aa98b932 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -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 -- 2.39.5