Re: [PATCH] tty/serial: emit CR before NL in RISC-V SBL console

Anup Patel
2019-01-10T16:17:22Z

On Thu, Jan 10, 2019 at 8:56 PM Andreas Schwab <schwab@suse.de> wrote:
>
> On Jan 10 2019, Anup Patel <anup@brainfault.org> wrote:
>
> > Instead of doing '\n' handling here, we should do it in BBL or
> > OpenSBI (i.e. SBI runtime firmware) otherwise all users of
> > SBI_CONSOLE_PUTCHAR (namely, Linux, FreeBSD,
> > FreeRTOS, U-Boot S-mode, etc) will endup having '\n'
> > handling.
>
> I don't think the serial driver should do NLCR handling on its own,
> without being instructed by the tty layer. Since the earlycon does not
> have a tty layer, it needs to handle it explicitly.

I tried to investigate more. What you suggest is correct
but we should use uart_console_write() API.

Instead of explicitly doing NLCR here, we should do
something as follows:

static void sbi_putc(struct uart_port *port, int c)
{
sbi_console_putchar(c);
}

static void sbi_console_write(struct console *con,
const char *s, unsigned n)
{
struct earlycon_device *dev = con->data;
uart_console_write(&dev->port, s, n, sbi_putc);
}

The uart_console_write() does the NLCR handling.

Regards,
Anup