64 lines
1.8 KiB
C
64 lines
1.8 KiB
C
#include <linux/serial_reg.h>
|
|
#include <linux/serial_8250.h>
|
|
|
|
#include "8250.h"
|
|
|
|
/*
|
|
* Freescale 16550 UART "driver", Copyright (C) 2011 Paul Gortmaker.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
* This isn't a full driver; it just provides an alternate IRQ
|
|
* handler to deal with an errata. Everything else is just
|
|
* using the bog standard 8250 support.
|
|
*
|
|
* We follow code flow of serial8250_default_handle_irq() but add
|
|
* a check for a break and insert a dummy read on the Rx for the
|
|
* immediately following IRQ event.
|
|
*
|
|
* We re-use the already existing "bug handling" lsr_saved_flags
|
|
* field to carry the "what we just did" information from the one
|
|
* IRQ event to the next one.
|
|
*/
|
|
|
|
int fsl8250_handle_irq(struct uart_port *port)
|
|
{
|
|
unsigned char lsr, orig_lsr;
|
|
unsigned long flags;
|
|
unsigned int iir;
|
|
struct uart_8250_port *up =
|
|
container_of(port, struct uart_8250_port, port);
|
|
|
|
spin_lock_irqsave(&up->port.lock, flags);
|
|
|
|
iir = port->serial_in(port, UART_IIR);
|
|
if (iir & UART_IIR_NO_INT) {
|
|
spin_unlock_irqrestore(&up->port.lock, flags);
|
|
return 0;
|
|
}
|
|
|
|
/* This is the WAR; if last event was BRK, then read and return */
|
|
if (unlikely(up->lsr_saved_flags & UART_LSR_BI)) {
|
|
up->lsr_saved_flags &= ~UART_LSR_BI;
|
|
port->serial_in(port, UART_RX);
|
|
spin_unlock_irqrestore(&up->port.lock, flags);
|
|
return 1;
|
|
}
|
|
|
|
lsr = orig_lsr = up->port.serial_in(&up->port, UART_LSR);
|
|
|
|
if (lsr & (UART_LSR_DR | UART_LSR_BI))
|
|
lsr = serial8250_rx_chars(up, lsr);
|
|
|
|
serial8250_modem_status(up);
|
|
|
|
if (lsr & UART_LSR_THRE)
|
|
serial8250_tx_chars(up);
|
|
|
|
up->lsr_saved_flags = orig_lsr;
|
|
spin_unlock_irqrestore(&up->port.lock, flags);
|
|
return 1;
|
|
}
|