Messages in this thread | | | From | Baolin Wang <> | Date | Thu, 19 Sep 2019 11:21:07 +0800 | Subject | Re: [PATCH v2] serial: sprd: Add polling IO support |
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Hi,
On Thu, 19 Sep 2019 at 11:10, Lanqing Liu <liuhhome@gmail.com> wrote: > > In order to access the UART without the interrupts, the kernel uses > the basic polling methods for IO with the device. With these methods > implemented, it is now possible to enable kgdb during early boot over serial. > > Signed-off-by: Lanqing Liu <liuhhome@gmail.com> > --- > Change from v1: > - Add poll_init() support.
Looks good to me and the KGDB can work well on my board, so feel free to add my tags: Reviewed-by: Baolin Wang <baolin.wang@linaro.org> Tested-by: Baolin Wang <baolin.wang@linaro.org>
> --- > drivers/tty/serial/sprd_serial.c | 33 +++++++++++++++++++++++++++++++++ > 1 file changed, 33 insertions(+) > > diff --git a/drivers/tty/serial/sprd_serial.c b/drivers/tty/serial/sprd_serial.c > index 73d71a4..d833160 100644 > --- a/drivers/tty/serial/sprd_serial.c > +++ b/drivers/tty/serial/sprd_serial.c > @@ -911,6 +911,34 @@ static void sprd_pm(struct uart_port *port, unsigned int state, > } > } > > +#ifdef CONFIG_CONSOLE_POLL > +static int sprd_poll_init(struct uart_port *port) > +{ > + if (port->state->pm_state != UART_PM_STATE_ON) { > + sprd_pm(port, UART_PM_STATE_ON, 0); > + port->state->pm_state = UART_PM_STATE_ON; > + } > + > + return 0; > +} > + > +static int sprd_poll_get_char(struct uart_port *port) > +{ > + while (!(serial_in(port, SPRD_STS1) & SPRD_RX_FIFO_CNT_MASK)) > + cpu_relax(); > + > + return serial_in(port, SPRD_RXD); > +} > + > +static void sprd_poll_put_char(struct uart_port *port, unsigned char ch) > +{ > + while (serial_in(port, SPRD_STS1) & SPRD_TX_FIFO_CNT_MASK) > + cpu_relax(); > + > + serial_out(port, SPRD_TXD, ch); > +} > +#endif > + > static const struct uart_ops serial_sprd_ops = { > .tx_empty = sprd_tx_empty, > .get_mctrl = sprd_get_mctrl, > @@ -928,6 +956,11 @@ static void sprd_pm(struct uart_port *port, unsigned int state, > .config_port = sprd_config_port, > .verify_port = sprd_verify_port, > .pm = sprd_pm, > +#ifdef CONFIG_CONSOLE_POLL > + .poll_init = sprd_poll_init, > + .poll_get_char = sprd_poll_get_char, > + .poll_put_char = sprd_poll_put_char, > +#endif > }; > > #ifdef CONFIG_SERIAL_SPRD_CONSOLE > -- > 1.9.1 >
-- Baolin Wang Best Regards
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