Commit cd1e40f0 authored by Mischa Jonker's avatar Mischa Jonker Committed by Linus Torvalds
Browse files

When a break signal is detected, the next character should be ignored. 



This was not implemented correctly for the pnx8xxx_uart driver.

[From further discussion:
Correct, you can look to it as two separate bugs:
a) the next character is not ignored while it should;
b) the status bits 31-8 are copied to the 'ch' variable while they shouldn't.

Both bugs prevent correct break signal handling (and therefore correct
behaviour of the magic SysRq key). Bug b didn't cause too much trouble
earlier because in most situations the status bits are all zero; for
this case they unfortunately aren't.
]

Signed-off-by: default avatarMischa Jonker <mischa.jonker@nxp.com>
Signed-off-by: default avatarAlan Cox <alan@redhat.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7fdd4f76

drivers/serial/pnx8xxx_uart.c

+12 −11
Original line number Diff line number Diff line
@@ -187,7 +187,7 @@ static void pnx8xxx_rx_chars(struct pnx8xxx_port *sport) 
	status = FIFO_TO_SM(serial_in(sport, PNX8XXX_FIFO)) |

		 ISTAT_TO_SM(serial_in(sport, PNX8XXX_ISTAT));

	while (status & FIFO_TO_SM(PNX8XXX_UART_FIFO_RXFIFO)) {

		ch = serial_in(sport, PNX8XXX_FIFO);

		ch = serial_in(sport, PNX8XXX_FIFO) & 0xff;



		sport->port.icount.rx++;
@@ -198,9 +198,16 @@ static void pnx8xxx_rx_chars(struct pnx8xxx_port *sport) 
		 * out of the main execution path

		 */

		if (status & (FIFO_TO_SM(PNX8XXX_UART_FIFO_RXFE |

					PNX8XXX_UART_FIFO_RXPAR) |

					PNX8XXX_UART_FIFO_RXPAR |

					PNX8XXX_UART_FIFO_RXBRK) |

			      ISTAT_TO_SM(PNX8XXX_UART_INT_RXOVRN))) {

			if (status & FIFO_TO_SM(PNX8XXX_UART_FIFO_RXPAR))

			if (status & FIFO_TO_SM(PNX8XXX_UART_FIFO_RXBRK)) {

				status &= ~(FIFO_TO_SM(PNX8XXX_UART_FIFO_RXFE) |

					FIFO_TO_SM(PNX8XXX_UART_FIFO_RXPAR));

				sport->port.icount.brk++;

				if (uart_handle_break(&sport->port))

					goto ignore_char;

			} else if (status & FIFO_TO_SM(PNX8XXX_UART_FIFO_RXPAR))

				sport->port.icount.parity++;

			else if (status & FIFO_TO_SM(PNX8XXX_UART_FIFO_RXFE))

				sport->port.icount.frame++;
@@ -284,14 +291,8 @@ static irqreturn_t pnx8xxx_int(int irq, void *dev_id) 
	/* Get the interrupts */

	status  = serial_in(sport, PNX8XXX_ISTAT) & serial_in(sport, PNX8XXX_IEN);



	/* Break signal received */

	if (status & PNX8XXX_UART_INT_BREAK) {

		sport->port.icount.brk++;

		uart_handle_break(&sport->port);

	}



	/* Byte received */

	if (status & PNX8XXX_UART_INT_RX)

	/* Byte or break signal received */

	if (status & (PNX8XXX_UART_INT_RX | PNX8XXX_UART_INT_BREAK))

		pnx8xxx_rx_chars(sport);



	/* TX holding register empty - transmit a byte */

CRA Git | Maintained and supported by SUSTech CRA and CCSE