serial/8250: export serial8250_read_char

jk-ozlabs · gregkh · commit ebbaf9ab9ebd · 2018-04-23T10:16:50.000+02:00
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 &lt;jk@ozlabs.org&gt;
Tested-by: Eddie James &lt;eajames@linux.vnet.ibm.com&gt;
Tested-by: Joel Stanley &lt;joel@jms.id.au&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
@@ -1680,7 +1680,7 @@ 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;
@@ -1740,6 +1740,7 @@ 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
@@ -163,6 +163,7 @@ 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);

Original file line number	Diff line number	Diff line change
`@@ -1680,7 +1680,7 @@ static void serial8250_enable_ms(struct uart_port *port)`
`1680`	`1680`	`serial8250_rpm_put(up);`
`1681`	`1681`	`}`
`1682`	`1682`
`1683`		`-static void serial8250_read_char(struct uart_8250_port *up, unsigned char lsr)`
	`1683`	`+void serial8250_read_char(struct uart_8250_port *up, unsigned char lsr)`
`1684`	`1684`	`{`
`1685`	`1685`	`struct uart_port *port = &up->port;`
`1686`	`1686`	`unsigned char ch;`
`@@ -1740,6 +1740,7 @@ static void serial8250_read_char(struct uart_8250_port *up, unsigned char lsr)`
`1740`	`1740`
`1741`	`1741`	`uart_insert_char(port, lsr, UART_LSR_OE, ch, flag);`
`1742`	`1742`	`}`
	`1743`	`+EXPORT_SYMBOL_GPL(serial8250_read_char);`
`1743`	`1744`
`1744`	`1745`	`/*`
`1745`	`1746`	`* serial8250_rx_chars: processes according to the passed in LSR`