From: Joerg Roedel <[email protected]> While debugging why my 8-port XR17V35X card does not work with the in-kernel serial driver, I found that some chip specific wakeup code is necessary to get it working.
Specificly the EFR_ECB bit needs to be set in the chip-specific UART_XR_EFR register, so that writing to a couple of other configuration bits is enabled. Cc: Peter Hurley <[email protected]> Cc: Michael Welling <[email protected]> Cc: Joe Schultz <[email protected]> Signed-off-by: Joerg Roedel <[email protected]> --- drivers/tty/serial/8250/8250_core.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c index 4506e40..de34db3 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -2176,6 +2176,18 @@ int serial8250_do_startup(struct uart_port *port) */ enable_rsa(up); #endif + + /* + * Do this right before clearing the FIFOs to prevent + * interrupt storm. + */ + if (port->type == PORT_XR17V35X) { + /* Wake up and initialize UART */ + serial_port_out(port, UART_XR_EFR, UART_EFR_ECB); + serial_port_out(port, UART_IER, 0); + serial_port_out(port, UART_LCR, 0); + } + /* * Clear the FIFO buffers and disable them. * (they will be reenabled in set_termios()) -- 1.8.4.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/
