82 lines
2.2 KiB
C
Executable file
82 lines
2.2 KiB
C
Executable file
// SPDX-License-Identifier: GPL-2.0
|
|
#include <linux/serial_reg.h>
|
|
#include <linux/serial_8250.h>
|
|
|
|
#include "8250.h"
|
|
|
|
/*
|
|
* Freescale 16550 UART "driver", Copyright (C) 2011 Paul Gortmaker.
|
|
*
|
|
* 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 = up_to_u8250p(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);
|
|
|
|
/* Process incoming characters first */
|
|
if ((lsr & (UART_LSR_DR | UART_LSR_BI)) &&
|
|
(up->ier & (UART_IER_RLSI | UART_IER_RDI))) {
|
|
lsr = serial8250_rx_chars(up, lsr);
|
|
}
|
|
|
|
/* Stop processing interrupts on input overrun */
|
|
if ((orig_lsr & UART_LSR_OE) && (up->overrun_backoff_time_ms > 0)) {
|
|
unsigned long delay;
|
|
|
|
up->ier = port->serial_in(port, UART_IER);
|
|
if (up->ier & (UART_IER_RLSI | UART_IER_RDI)) {
|
|
port->ops->stop_rx(port);
|
|
} else {
|
|
/* Keep restarting the timer until
|
|
* the input overrun subsides.
|
|
*/
|
|
cancel_delayed_work(&up->overrun_backoff);
|
|
}
|
|
|
|
delay = msecs_to_jiffies(up->overrun_backoff_time_ms);
|
|
schedule_delayed_work(&up->overrun_backoff, delay);
|
|
}
|
|
|
|
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;
|
|
}
|
|
EXPORT_SYMBOL_GPL(fsl8250_handle_irq);
|