Implements the necessary callbacks to switch the imx console driver to
perform as an nbcon console.
Add implementations for the nbcon consoles (write_atomic, write_thread,
driver_enter, driver_exit) and add CON_NBCON to the initial flags.
The legacy code is kept in order to easily switch back to legacy mode
by defining CONFIG_SERIAL_IMX_LEGACY_CONSOLE.
Signed-off-by: Esben Haabendal <esben@xxxxxxxxxx>
---
drivers/tty/serial/imx.c | 154 ++++++++++++++++++++++++++++++++++++++-
1 file changed, 153 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 16661827277e..7030fa2bcaea 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -230,6 +230,8 @@ struct imx_port {
unsigned int saved_reg[10];
bool context_saved;
+ bool console_newline_needed;
+
enum imx_tx_state tx_state;
struct hrtimer trigger_start_tx;
struct hrtimer trigger_stop_tx;
@@ -1985,8 +1987,14 @@ static void imx_uart_console_putchar(struct uart_port *port, unsigned char ch)
barrier();
imx_uart_writel(sport, ch, URTX0);
+
+ if (ch == '\n')
+ sport->console_newline_needed = false;
+ else
+ sport->console_newline_needed = true;
}
+#ifdef CONFIG_SERIAL_IMX_LEGACY_CONSOLE
/*
* Interrupts are disabled on entering
*/
@@ -2034,6 +2042,140 @@ imx_uart_console_write(struct console *co, const char *s, unsigned int count)
if (locked)
uart_port_unlock_irqrestore(&sport->port, flags);
}
+#else
+static void imx_uart_console_driver_enter(struct console *co, unsigned long *flags)
+{
+ struct uart_port *up = &imx_uart_ports[co->index]->port;
+
+ return __uart_port_lock_irqsave(up, flags);
+}
+
+static void imx_uart_console_driver_exit(struct console *co, unsigned long flags)
+{
+ struct uart_port *up = &imx_uart_ports[co->index]->port;
+
+ return __uart_port_unlock_irqrestore(up, flags);
+}
+
+static bool imx_uart_console_write_atomic(struct console *co,
+ struct nbcon_write_context *wctxt)
+{
+ struct imx_port *sport = imx_uart_ports[co->index];
+ struct uart_port *port = &sport->port;
+ struct imx_port_ucrs old_ucr;
+ unsigned int ucr1, usr2;
+
+ if (!nbcon_enter_unsafe(wctxt))
+ return false;
+
+ /*
+ * First, save UCR1/2/3 and then disable interrupts
+ */
+ imx_uart_ucrs_save(sport, &old_ucr);
+ ucr1 = old_ucr.ucr1;
+
+ if (imx_uart_is_imx1(sport))
+ ucr1 |= IMX1_UCR1_UARTCLKEN;
+ ucr1 |= UCR1_UARTEN;
+ ucr1 &= ~(UCR1_TRDYEN | UCR1_RRDYEN | UCR1_RTSDEN);
+
+ imx_uart_writel(sport, ucr1, UCR1);
+
+ imx_uart_writel(sport, old_ucr.ucr2 | UCR2_TXEN, UCR2);
+
+ if (sport->console_newline_needed)
+ uart_console_write(port, "\n", 1, imx_uart_console_putchar);
+ uart_console_write(port, wctxt->outbuf, wctxt->len,
+ imx_uart_console_putchar);
+
+ /*
+ * Finally, wait for transmitter to become empty
+ * and restore UCR1/2/3
+ */
+ read_poll_timeout_atomic(imx_uart_readl, usr2, usr2 & USR2_TXDC,
+ 1, 10000, false, sport, USR2);
+ imx_uart_ucrs_restore(sport, &old_ucr);
+
+ /* Success if no handover/takeover. */
+ return nbcon_exit_unsafe(wctxt);
+}
+
+static bool imx_uart_console_write_thread(struct console *co,
+ struct nbcon_write_context *wctxt)
+{
+ struct imx_port *sport = imx_uart_ports[co->index];
+ struct uart_port *port = &sport->port;
+ struct imx_port_ucrs old_ucr;
+ unsigned int ucr1, usr2;
+ bool done = false;
+
+ if (!nbcon_enter_unsafe(wctxt))
+ return false;
+
+ /*
+ * First, save UCR1/2/3 and then disable interrupts
+ */
+ imx_uart_ucrs_save(sport, &old_ucr);
+ ucr1 = old_ucr.ucr1;
+
+ if (imx_uart_is_imx1(sport))
+ ucr1 |= IMX1_UCR1_UARTCLKEN;
+ ucr1 |= UCR1_UARTEN;
+ ucr1 &= ~(UCR1_TRDYEN | UCR1_RRDYEN | UCR1_RTSDEN);
+
+ imx_uart_writel(sport, ucr1, UCR1);
+
+ imx_uart_writel(sport, old_ucr.ucr2 | UCR2_TXEN, UCR2);
+
+ if (nbcon_exit_unsafe(wctxt)) {
+ int len = READ_ONCE(wctxt->len);
+ int i;
+
+ /*
+ * Write out the message. Toggle unsafe for each byte in order
+ * to give another (higher priority) context the opportunity
+ * for a friendly takeover. If such a takeover occurs, this
+ * context must reacquire ownership in order to perform final
+ * actions (such as re-enabling the interrupts).
+ *
+ * IMPORTANT: wctxt->outbuf and wctxt->len are no longer valid
+ * after a reacquire so writing the message must be
+ * aborted.
+ */
+ for (i = 0; i < len; i++) {
+ if (!nbcon_enter_unsafe(wctxt)) {
+ nbcon_reacquire(wctxt);
+ break;
+ }
+
+ uart_console_write(port, wctxt->outbuf + i, 1,
+ imx_uart_console_putchar);
+
+ if (!nbcon_exit_unsafe(wctxt)) {
+ nbcon_reacquire(wctxt);
+ break;
+ }
+ }
+ done = (i == len);
+ } else {
+ nbcon_reacquire(wctxt);
+ }
+
+ while (!nbcon_enter_unsafe(wctxt))
+ nbcon_reacquire(wctxt);
+
+ /*
+ * Finally, wait for transmitter to become empty
+ * and restore UCR1/2/3
+ */
+ read_poll_timeout(imx_uart_readl, usr2, usr2 & USR2_TXDC,
+ 1, 10000, false, sport, USR2);
+ imx_uart_ucrs_restore(sport, &old_ucr);
+
+ /* Success if no handover/takeover and message fully printed. */
+ return (nbcon_exit_unsafe(wctxt) && done);
+}
+#endif /* CONFIG_SERIAL_IMX_LEGACY_CONSOLE */
/*
* If the port was already initialised (eg, by a boot loader),
@@ -2124,6 +2266,8 @@ imx_uart_console_setup(struct console *co, char *options)
if (retval)
goto error_console;
+ sport->console_newline_needed = false;
+
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
else
@@ -2160,11 +2304,19 @@ imx_uart_console_exit(struct console *co)
static struct uart_driver imx_uart_uart_driver;
static struct console imx_uart_console = {
.name = DEV_NAME,
+#ifdef CONFIG_SERIAL_IMX_LEGACY_CONSOLE
.write = imx_uart_console_write,
+ .flags = CON_PRINTBUFFER,
+#else
+ .write_atomic = imx_uart_console_write_atomic,
+ .write_thread = imx_uart_console_write_thread,
+ .driver_enter = imx_uart_console_driver_enter,
+ .driver_exit = imx_uart_console_driver_exit,
+ .flags = CON_PRINTBUFFER | CON_NBCON,
+#endif
.device = uart_console_device,
.setup = imx_uart_console_setup,
.exit = imx_uart_console_exit,
- .flags = CON_PRINTBUFFER,
.index = -1,
.data = &imx_uart_uart_driver,
};
--
2.44.0
