Hi Yixun, On 06/09/2017 15:52, Yixun Lan wrote: > This dirver try to implement the Magic SysRq support[1] for > Amlogic Inc's meson platfo Please fix these typos. > From the hardware perspective, the UART IP can't detect the 'BREAK' command > clearly via the status register. Instead, we rely on the combination of > 'FRAME_ERR bit && ch == 0', and it works fine. > > [1] Documentation/admin-guide/sysrq.rst > > Signed-off-by: Yixun Lan <dlan@xxxxxxxxxx> > > --- > Changes since v1 at [0]: > - add changelog & a few more comments > > [0] https://patchwork.kernel.org/patch/9728475/ > --- > drivers/tty/serial/meson_uart.c | 18 ++++++++++++++++-- > 1 file changed, 16 insertions(+), 2 deletions(-) > > diff --git a/drivers/tty/serial/meson_uart.c b/drivers/tty/serial/meson_uart.c > index 42e4a4c7597f..3fea24bafd80 100644 > --- a/drivers/tty/serial/meson_uart.c > +++ b/drivers/tty/serial/meson_uart.c > @@ -14,6 +14,10 @@ > * > */ > > +#if defined(CONFIG_SERIAL_MESON_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) > +#define SUPPORT_SYSRQ > +#endif > + > #include <linux/clk.h> > #include <linux/console.h> > #include <linux/delay.h> > @@ -183,12 +187,12 @@ static void meson_receive_chars(struct uart_port *port) > { > struct tty_port *tport = &port->state->port; > char flag; > - u32 status, ch, mode; > + u32 ostatus, status, ch, mode; > > do { > flag = TTY_NORMAL; > port->icount.rx++; > - status = readl(port->membase + AML_UART_STATUS); > + ostatus = status = readl(port->membase + AML_UART_STATUS); > > if (status & AML_UART_ERR) { > if (status & AML_UART_TX_FIFO_WERR) > @@ -216,6 +220,16 @@ static void meson_receive_chars(struct uart_port *port) > ch = readl(port->membase + AML_UART_RFIFO); > ch &= 0xff; > > + if ((ostatus & AML_UART_FRAME_ERR) && (ch == 0)) { > + port->icount.brk++; > + flag = TTY_BREAK; > + if (uart_handle_break(port)) > + continue; > + } > + > + if (uart_handle_sysrq_char(port, ch)) > + continue; > + > if ((status & port->ignore_status_mask) == 0) > tty_insert_flip_char(tport, ch, flag); > > Reviewed-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
