Re: [PATCH v2 17/25] tty: serial: samsung_tty: Separate S3C64XX ops structure

Krzysztof Kozlowski
2021-02-15T18:08:03Z

On Mon, Feb 15, 2021 at 09:17:05PM +0900, Hector Martin wrote:
> Instead of patching a single global ops structure depending on the port
> type, use a separate s3c64xx_serial_ops for the S3C64XX type. This
> allows us to mark the structures as const.
>
> Also split out s3c64xx_serial_shutdown into a separate function now that
> we have a separate ops structure; this avoids excessive branching
> control flow and mirrors s3c64xx_serial_startup. tx_claimed and
> rx_claimed are only used in the S3C24XX functions.
>
> Signed-off-by: Hector Martin <marcan@marcan.st>
> ---
> drivers/tty/serial/samsung_tty.c | 69 ++++++++++++++++++++++++--------
> 1 file changed, 53 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
> index 8ae3e03fbd8c..6b661f3ec1ae 100644
> --- a/drivers/tty/serial/samsung_tty.c
> +++ b/drivers/tty/serial/samsung_tty.c
> @@ -1098,27 +1098,36 @@ static void s3c24xx_serial_shutdown(struct uart_port *port)
> struct s3c24xx_uart_port *ourport = to_ourport(port);
>
> if (ourport->tx_claimed) {
> - if (!s3c24xx_serial_has_interrupt_mask(port))
> - free_irq(ourport->tx_irq, ourport);
> + free_irq(ourport->tx_irq, ourport);
> ourport->tx_enabled = 0;
> ourport->tx_claimed = 0;
> ourport->tx_mode = 0;
> }
>
> if (ourport->rx_claimed) {
> - if (!s3c24xx_serial_has_interrupt_mask(port))
> - free_irq(ourport->rx_irq, ourport);
> + free_irq(ourport->rx_irq, ourport);
> ourport->rx_claimed = 0;
> ourport->rx_enabled = 0;
> }
>
> - /* Clear pending interrupts and mask all interrupts */
> - if (s3c24xx_serial_has_interrupt_mask(port)) {
> - free_irq(port->irq, ourport);
> + if (ourport->dma)
> + s3c24xx_serial_release_dma(ourport);
>
> - wr_regl(port, S3C64XX_UINTP, 0xf);
> - wr_regl(port, S3C64XX_UINTM, 0xf);
> - }
> + ourport->tx_in_progress = 0;
> +}
> +
> +static void s3c64xx_serial_shutdown(struct uart_port *port)
> +{
> + struct s3c24xx_uart_port *ourport = to_ourport(port);
> +
> + free_irq(port->irq, ourport);
> +
> + wr_regl(port, S3C64XX_UINTP, 0xf);
> + wr_regl(port, S3C64XX_UINTM, 0xf);
> +
> + ourport->tx_enabled = 0;
> + ourport->tx_mode = 0;
> + ourport->rx_enabled = 0;

For S3C64xx type this is not equivalent: the assignments were
happening before free_irq() and wr_regl(). Honestly I don't know whether
it matters (except some barriers coming from these functions) but please
do not change the order of code in this patch. If needed, the
re-ordering should be a patch on its own. With explanation why.

>
> if (ourport->dma)
> s3c24xx_serial_release_dma(ourport);
> @@ -1193,9 +1202,7 @@ static int s3c64xx_serial_startup(struct uart_port *port)
>
> /* For compatibility with s3c24xx Soc's */
> ourport->rx_enabled = 1;
> - ourport->rx_claimed = 1;
> ourport->tx_enabled = 0;
> - ourport->tx_claimed = 1;
>
> spin_lock_irqsave(&port->lock, flags);
>
> @@ -1631,6 +1638,29 @@ static struct uart_ops s3c24xx_serial_ops = {
> #endif
> };
>
> +static const struct uart_ops s3c64xx_serial_ops = {
> + .pm = s3c24xx_serial_pm,
> + .tx_empty = s3c24xx_serial_tx_empty,
> + .get_mctrl = s3c24xx_serial_get_mctrl,
> + .set_mctrl = s3c24xx_serial_set_mctrl,
> + .stop_tx = s3c24xx_serial_stop_tx,
> + .start_tx = s3c24xx_serial_start_tx,
> + .stop_rx = s3c24xx_serial_stop_rx,
> + .break_ctl = s3c24xx_serial_break_ctl,
> + .startup = s3c64xx_serial_startup,
> + .shutdown = s3c64xx_serial_shutdown,
> + .set_termios = s3c24xx_serial_set_termios,
> + .type = s3c24xx_serial_type,
> + .release_port = s3c24xx_serial_release_port,
> + .request_port = s3c24xx_serial_request_port,
> + .config_port = s3c24xx_serial_config_port,
> + .verify_port = s3c24xx_serial_verify_port,
> +#if defined(CONFIG_SERIAL_SAMSUNG_CONSOLE) && defined(CONFIG_CONSOLE_POLL)
> + .poll_get_char = s3c24xx_serial_get_poll_char,
> + .poll_put_char = s3c24xx_serial_put_poll_char,
> +#endif
> +};
> +

Make the s3c24xx_serial_ops const as well.

Best regards,
Krzysztof