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serial/8250: export serial8250_read_char

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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@ozlabs.org>
Tested-by: Eddie James <eajames@linux.vnet.ibm.com>
Tested-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jeremy Kerr 2018-03-27 11:48:25 +08:00 committed by Greg Kroah-Hartman
parent c5f78b1fe4
commit ebbaf9ab9e
2 changed files with 3 additions and 1 deletions
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3
drivers/tty/serial/8250/8250_port.c
View file

@ -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

1
include/linux/serial_8250.h
View file

@ -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);