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Commit e44aabd6 authored by Marcus Folkesson's avatar Marcus Folkesson Committed by Greg Kroah-Hartman
Browse files

serial: pxa: work around for errata #20 



Errata E20: UART: Character Timeout interrupt remains set under certain
software conditions.

Implication: The software servicing the UART can be trapped in an infinite loop.

Signed-off-by: default avatarMarcus Folkesson <marcus.folkesson@gmail.com>
Cc: stable <stable@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 7d4008eb

drivers/tty/serial/pxa.c

+20 −0
Original line number Original line Diff line number Diff line
@@ -100,6 +100,16 @@ static inline void receive_chars(struct uart_pxa_port *up, int *status) 
	int max_count = 256;

	int max_count = 256;





	do {

	do {

		/* work around Errata #20 according to

		 * Intel(R) PXA27x Processor Family

		 * Specification Update (May 2005)

		 *

		 * Step 2

		 * Disable the Reciever Time Out Interrupt via IER[RTOEI]

		 */

		up->ier &= ~UART_IER_RTOIE;

		serial_out(up, UART_IER, up->ier);



		ch = serial_in(up, UART_RX);

		ch = serial_in(up, UART_RX);

		flag = TTY_NORMAL;

		flag = TTY_NORMAL;

		up->port.icount.rx++;

		up->port.icount.rx++;
@@ -156,6 +166,16 @@ static inline void receive_chars(struct uart_pxa_port *up, int *status) 
		*status = serial_in(up, UART_LSR);

		*status = serial_in(up, UART_LSR);

	} while ((*status & UART_LSR_DR) && (max_count-- > 0));

	} while ((*status & UART_LSR_DR) && (max_count-- > 0));

	tty_flip_buffer_push(tty);

	tty_flip_buffer_push(tty);



	/* work around Errata #20 according to

	 * Intel(R) PXA27x Processor Family

	 * Specification Update (May 2005)

	 *

	 * Step 6:

	 * No more data in FIFO: Re-enable RTO interrupt via IER[RTOIE]

	 */

	up->ier |= UART_IER_RTOIE;

	serial_out(up, UART_IER, up->ier);

}

}





static void transmit_chars(struct uart_pxa_port *up)

static void transmit_chars(struct uart_pxa_port *up)