Add support for KGDB in stm32 serial driver by implementing characters
polling callbacks (poll_init, poll_get_char and poll_put_char).
Signed-off-by: Erwan Le Ray <erwan.leray@xxxxxxxxxxx>
Signed-off-by: Jean Philippe Romain <jean-philippe.romain@xxxxxxxxxxx>
Signed-off-by: Valentin Caron <valentin.caron@xxxxxxxxxxx>
---
drivers/tty/serial/stm32-usart.c | 37 ++++++++++++++++++++++++++++++--
1 file changed, 35 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 83895da84891..4307c822afe4 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -37,6 +37,7 @@
static void stm32_usart_stop_tx(struct uart_port *port);
static void stm32_usart_transmit_chars(struct uart_port *port);
+static void __maybe_unused stm32_usart_console_putchar(struct uart_port *port, unsigned char ch);
static inline struct stm32_port *to_stm32_port(struct uart_port *port)
{
@@ -1222,6 +1223,33 @@ static void stm32_usart_pm(struct uart_port *port, unsigned int state,
}
}
+#if defined(CONFIG_CONSOLE_POLL)
+
+ /* Callbacks for characters polling in debug context (i.e. KGDB). */
+static int stm32_usart_poll_init(struct uart_port *port)
+{
+ struct stm32_port *stm32_port = to_stm32_port(port);
+
+ return clk_prepare_enable(stm32_port->clk);
+}
+
+static int stm32_usart_poll_get_char(struct uart_port *port)
+{
+ struct stm32_port *stm32_port = to_stm32_port(port);
+ const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
+
+ if (!(readl_relaxed(port->membase + ofs->isr) & USART_SR_RXNE))
+ return NO_POLL_CHAR;
+
+ return readl_relaxed(port->membase + ofs->rdr) & stm32_port->rdr_mask;
+}
+
+static void stm32_usart_poll_put_char(struct uart_port *port, unsigned char ch)
+{
+ stm32_usart_console_putchar(port, ch);
+}
+#endif /* CONFIG_CONSOLE_POLL */
+
static const struct uart_ops stm32_uart_ops = {
.tx_empty = stm32_usart_tx_empty,
.set_mctrl = stm32_usart_set_mctrl,
@@ -1243,6 +1271,11 @@ static const struct uart_ops stm32_uart_ops = {
.request_port = stm32_usart_request_port,
.config_port = stm32_usart_config_port,
.verify_port = stm32_usart_verify_port,
+#if defined(CONFIG_CONSOLE_POLL)
+ .poll_init = stm32_usart_poll_init,
+ .poll_get_char = stm32_usart_poll_get_char,
+ .poll_put_char = stm32_usart_poll_put_char,
+#endif /* CONFIG_CONSOLE_POLL */
};
/*
@@ -1640,8 +1673,7 @@ static int stm32_usart_serial_remove(struct platform_device *pdev)
return 0;
}
-#ifdef CONFIG_SERIAL_STM32_CONSOLE
-static void stm32_usart_console_putchar(struct uart_port *port, unsigned char ch)
+static void __maybe_unused stm32_usart_console_putchar(struct uart_port *port, unsigned char ch)
{
struct stm32_port *stm32_port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
@@ -1658,6 +1690,7 @@ static void stm32_usart_console_putchar(struct uart_port *port, unsigned char ch
writel_relaxed(ch, port->membase + ofs->tdr);
}
+#ifdef CONFIG_SERIAL_STM32_CONSOLE
static void stm32_usart_console_write(struct console *co, const char *s,
unsigned int cnt)
{
--
2.25.1
