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SubjectRe: [PATCH 1/1] tty: serial: owl: Add support for kernel debugger
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Hi,

Am 29.05.20 um 17:50 schrieb Cristian Ciocaltea:
> Implement poll_put_char and poll_get_char callbacks in struct uart_ops
> that enables OWL UART to be used for KGDB debugging over serial line.
>
> Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@gmail.com>
> ---
> drivers/tty/serial/owl-uart.c | 45 ++++++++++++++++++++++++++++++-----
> 1 file changed, 39 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/tty/serial/owl-uart.c b/drivers/tty/serial/owl-uart.c
> index c2fa2f15d50a..26dcc374dec5 100644
> --- a/drivers/tty/serial/owl-uart.c
> +++ b/drivers/tty/serial/owl-uart.c
> @@ -12,6 +12,7 @@
> #include <linux/console.h>
> #include <linux/delay.h>
> #include <linux/io.h>
> +#include <linux/iopoll.h>
> #include <linux/module.h>
> #include <linux/of.h>
> #include <linux/platform_device.h>
> @@ -20,13 +21,13 @@
> #include <linux/tty.h>
> #include <linux/tty_flip.h>
>
> -#define OWL_UART_PORT_NUM 7
> -#define OWL_UART_DEV_NAME "ttyOWL"
> +#define OWL_UART_PORT_NUM 7
> +#define OWL_UART_DEV_NAME "ttyOWL"
>
> -#define OWL_UART_CTL 0x000
> -#define OWL_UART_RXDAT 0x004
> -#define OWL_UART_TXDAT 0x008
> -#define OWL_UART_STAT 0x00c
> +#define OWL_UART_CTL 0x000
> +#define OWL_UART_RXDAT 0x004
> +#define OWL_UART_TXDAT 0x008
> +#define OWL_UART_STAT 0x00c

Please do not unnecessarily re-indent kernel code. You can do so when
you're actually adding something new.

>
> #define OWL_UART_CTL_DWLS_MASK GENMASK(1, 0)
> #define OWL_UART_CTL_DWLS_5BITS (0x0 << 0)
> @@ -461,6 +462,34 @@ static void owl_uart_config_port(struct uart_port *port, int flags)
> }
> }
>
> +#ifdef CONFIG_CONSOLE_POLL
> +
> +static int owl_uart_poll_get_char(struct uart_port *port)
> +{
> + u32 c = NO_POLL_CHAR;
> +
> + if (!(owl_uart_read(port, OWL_UART_STAT) & OWL_UART_STAT_RFEM))
> + c = owl_uart_read(port, OWL_UART_RXDAT);
> +
> + return c;
> +}
> +
> +static void owl_uart_poll_put_char(struct uart_port *port, unsigned char c)
> +{
> + /* Wait while TX FIFO is full */
> + while (owl_uart_read(port, OWL_UART_STAT) & OWL_UART_STAT_TFFU)
> + cpu_relax();
> +
> + /* Send the character out */
> + owl_uart_write(port, c, OWL_UART_TXDAT);
> +
> + /* Wait for transmitter to become empty */
> + while (owl_uart_read(port, OWL_UART_STAT) & OWL_UART_STAT_TRFL_MASK)
> + cpu_relax();
> +}

How is this different from earlycon? I dislike that this is being
open-coded. Please try to reuse existing functions for this.

Regards,
Andreas

> +
> +#endif /* CONFIG_CONSOLE_POLL */
> +
> static const struct uart_ops owl_uart_ops = {
> .set_mctrl = owl_uart_set_mctrl,
> .get_mctrl = owl_uart_get_mctrl,
> @@ -476,6 +505,10 @@ static const struct uart_ops owl_uart_ops = {
> .request_port = owl_uart_request_port,
> .release_port = owl_uart_release_port,
> .verify_port = owl_uart_verify_port,
> +#ifdef CONFIG_CONSOLE_POLL
> + .poll_get_char = owl_uart_poll_get_char,
> + .poll_put_char = owl_uart_poll_put_char,
> +#endif
> };
>
> #ifdef CONFIG_SERIAL_OWL_CONSOLE
>


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