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Commit 5935a2b3 authored by Yasir-Khan's avatar Yasir-Khan Committed by Greg Kroah-Hartman
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serial: xuartps: Enable uart loopback mode 



This patch adds xilinx uart loopback support by modifying the
cdns_uart_set_mctrl function to handle the switch to loopback mode.
After this patch, the loopback mode can be enabled/disabled by
setting/clearing the TIOCM_LOOP modem bit via TIOCMBIS/TIOCMBIC
ioctls respectively.

Signed-off-by: default avatarYasir-Khan <yasir_khan@mentor.com>
Signed-off-by: default avatarMichal Simek <michal.simek@xilinx.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent aa75941c

drivers/tty/serial/xilinx_uartps.c

+9 −0
Original line number Diff line number Diff line
@@ -93,6 +93,7 @@ MODULE_PARM_DESC(rx_timeout, "Rx timeout, 1-255"); 
#define CDNS_UART_MR_CLKSEL		0x00000001  /* Pre-scalar selection */

#define CDNS_UART_MR_CHMODE_L_LOOP	0x00000200  /* Local loop back mode */

#define CDNS_UART_MR_CHMODE_NORM	0x00000000  /* Normal mode */

#define CDNS_UART_MR_CHMODE_MASK	0x00000300  /* Mask for mode bits */



#define CDNS_UART_MR_STOPMODE_2_BIT	0x00000080  /* 2 stop bits */

#define CDNS_UART_MR_STOPMODE_1_BIT	0x00000000  /* 1 stop bit */
@@ -998,17 +999,25 @@ static unsigned int cdns_uart_get_mctrl(struct uart_port *port) 
static void cdns_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)

{

	u32 val;

	u32 mode_reg;



	val = readl(port->membase + CDNS_UART_MODEMCR);

	mode_reg = readl(port->membase + CDNS_UART_MR);



	val &= ~(CDNS_UART_MODEMCR_RTS | CDNS_UART_MODEMCR_DTR);

	mode_reg &= ~CDNS_UART_MR_CHMODE_MASK;



	if (mctrl & TIOCM_RTS)

		val |= CDNS_UART_MODEMCR_RTS;

	if (mctrl & TIOCM_DTR)

		val |= CDNS_UART_MODEMCR_DTR;

	if (mctrl & TIOCM_LOOP)

		mode_reg |= CDNS_UART_MR_CHMODE_L_LOOP;

	else

		mode_reg |= CDNS_UART_MR_CHMODE_NORM;



	writel(val, port->membase + CDNS_UART_MODEMCR);

	writel(mode_reg, port->membase + CDNS_UART_MR);

}



#ifdef CONFIG_CONSOLE_POLL