From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933617Ab1KJDTy (ORCPT ); Wed, 9 Nov 2011 22:19:54 -0500 Received: from cantor2.suse.de ([195.135.220.15]:41549 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933598Ab1KJDTt (ORCPT ); Wed, 9 Nov 2011 22:19:49 -0500 X-Mailbox-Line: From gregkh@clark.kroah.org Wed Nov 9 13:27:01 2011 Message-Id: <20111109212701.644148540@clark.kroah.org> User-Agent: quilt/0.48-16.4 Date: Wed, 09 Nov 2011 13:25:35 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Marcus Folkesson Subject: [013/262] serial: pxa: work around for errata #20 In-Reply-To: <20111109212847.GA20838@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Marcus Folkesson commit e44aabd649c80e8be16ede3ed3cbff6fb2561ca9 upstream. 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: Marcus Folkesson Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/pxa.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) --- a/drivers/tty/serial/pxa.c +++ b/drivers/tty/serial/pxa.c @@ -100,6 +100,16 @@ static inline void receive_chars(struct int max_count = 256; 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); flag = TTY_NORMAL; up->port.icount.rx++; @@ -156,6 +166,16 @@ static inline void receive_chars(struct *status = serial_in(up, UART_LSR); } while ((*status & UART_LSR_DR) && (max_count-- > 0)); 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)