Currently, we export serial8250_rx_chars, which does a whole bunch of
reads from the 8250 data register, without any form of flow control
between reads.
An upcoming change to the aspeed vuart driver implements more
fine-grained flow control in the interrupt handler, requiring
character-at-a-time control over the rx path.
This change exports serial8250_read_char to allow this.
Signed-off-by: Jeremy Kerr <jk@xxxxxxxxxx>
---
drivers/tty/serial/8250/8250_port.c | 3 ++-
include/linux/serial_8250.h | 1 +
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index a5fe0e66c607..ea435406936c 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1650,7 +1650,7 @@ static void serial8250_enable_ms(struct uart_port *port)
serial8250_rpm_put(up);
}
-static void serial8250_read_char(struct uart_8250_port *up, unsigned char lsr)
+void serial8250_read_char(struct uart_8250_port *up, unsigned char lsr)
{
struct uart_port *port = &up->port;
unsigned char ch;
@@ -1710,6 +1710,7 @@ static void serial8250_read_char(struct uart_8250_port *up, unsigned char lsr)
uart_insert_char(port, lsr, UART_LSR_OE, ch, flag);
}
+EXPORT_SYMBOL_GPL(serial8250_read_char);
/*
* serial8250_rx_chars: processes according to the passed in LSR
diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
index 61fbb440449c..4639a3608614 100644
--- a/include/linux/serial_8250.h
+++ b/include/linux/serial_8250.h
@@ -162,6 +162,7 @@ extern void serial8250_do_set_mctrl(struct uart_port *port, unsigned int mctrl);
extern int fsl8250_handle_irq(struct uart_port *port);
int serial8250_handle_irq(struct uart_port *port, unsigned int iir);
unsigned char serial8250_rx_chars(struct uart_8250_port *up, unsigned char lsr);
+void serial8250_read_char(struct uart_8250_port *up, unsigned char lsr);
void serial8250_tx_chars(struct uart_8250_port *up);
unsigned int serial8250_modem_status(struct uart_8250_port *up);
void serial8250_init_port(struct uart_8250_port *up);
--
2.14.1
--
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