On Tue, 03 Mar 2020 00:41:40 PST (-0800), vincent.chen@xxxxxxxxxx wrote:
Add CONSOLE_POLL support for future KGDB porting.
Signed-off-by: Vincent Chen <vincent.chen@xxxxxxxxxx>
---
drivers/tty/serial/sifive.c | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/drivers/tty/serial/sifive.c b/drivers/tty/serial/sifive.c
index d5f81b98e4d7..acdbaca4de36 100644
--- a/drivers/tty/serial/sifive.c
+++ b/drivers/tty/serial/sifive.c
@@ -818,6 +818,29 @@ static int __init sifive_serial_console_setup(struct console *co, char *options)
return uart_set_options(&ssp->port, co, baud, parity, bits, flow);
}
+#ifdef CONFIG_CONSOLE_POLL
+static int sifive_serial_poll_get_char(struct uart_port *port)
+{
+ struct sifive_serial_port *ssp = port_to_sifive_serial_port(port);
+ char is_empty, ch;
+
+ ch = __ssp_receive_char(ssp, &is_empty);
+ if (is_empty)
+ return NO_POLL_CHAR;
+
+ return ch;
+}
+
+static void sifive_serial_poll_put_char(struct uart_port *port,
+ unsigned char c)
+{
+ struct sifive_serial_port *ssp = port_to_sifive_serial_port(port);
+
+ sifive_serial_console_putchar(port, c);
+ __ssp_wait_for_xmitr(ssp);
So we still have that TX watermark bug in the SiFive UARTs. If this function
is supposed to wait until the word is actually out on the line then this isn't
sufficient, but if it's just supposed to wait until the next write won't block
then this is fine.
I'm not really a serial person, so mabye someone else knows? For those
unfamiliar with the issue, there's a pretty good description in the patch to
fix it
https://github.com/sifive/sifive-blocks/pull/90
Poking around we don't have any PRE_RATE_CHANGE hook, so I'm going to take a
whack at adding one -- not really related to this patch, though.
+}
+#endif /* CONFIG_CONSOLE_POLL */
+
static struct uart_driver sifive_serial_uart_driver;
static struct console sifive_serial_console = {
@@ -877,6 +900,10 @@ static const struct uart_ops sifive_serial_uops = {
.request_port = sifive_serial_request_port,
.config_port = sifive_serial_config_port,
.verify_port = sifive_serial_verify_port,
+#ifdef CONFIG_CONSOLE_POLL
+ .poll_get_char = sifive_serial_poll_get_char,
+ .poll_put_char = sifive_serial_poll_put_char,
+#endif
};
static struct uart_driver sifive_serial_uart_driver = {
