From mboxrd@z Thu Jan 1 00:00:00 1970 From: sonic zhang Subject: [PATCH][bfin-sport-uart] Walk around RX underflow hardware issue in 32-bit SPORT RX reading Date: Fri, 18 Sep 2009 17:05:47 +0800 Message-ID: <1253264747.22138.2.camel@eight.analog.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from nwd2mail10.analog.com ([137.71.25.55]:20309 "EHLO nwd2mail10.analog.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751023AbZIRJEs (ORCPT ); Fri, 18 Sep 2009 05:04:48 -0400 Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Alan Cox , Linux Kernel , Linux Serial Disable local interrupts in 32-bit reading from SPORT RX MMR to walk around the RX underflow hardware issue when this reading is interrupted by the other IRQ. Signed-off-by: Sonic Zhang --- drivers/serial/bfin_sport_uart.h | 15 ++++++++++++++- 1 files changed, 14 insertions(+), 1 deletions(-) diff --git a/drivers/serial/bfin_sport_uart.h b/drivers/serial/bfin_sport_uart.h index 671d41c..46e793e 100644 --- a/drivers/serial/bfin_sport_uart.h +++ b/drivers/serial/bfin_sport_uart.h @@ -43,7 +43,20 @@ #define SPORT_GET_TFSDIV(sport) bfin_read16(((sport)->port.membase + OFFSET_TFSDIV)) #define SPORT_GET_TX(sport) bfin_read16(((sport)->port.membase + OFFSET_TX)) #define SPORT_GET_RX(sport) bfin_read16(((sport)->port.membase + OFFSET_RX)) -#define SPORT_GET_RX32(sport) bfin_read32(((sport)->port.membase + OFFSET_RX)) +/* + * Disable local interrupt to walk around the fake RX underflow error + * when do 32-bit reading from RX fifois interrupted by other interrupt. + * This is a possible hardware anomaly. After it is logged officially, + * the official anomaly id should be listed bellow. + */ +#define SPORT_GET_RX32(sport) \ +({ \ + unsigned int __ret; \ + local_irq_disable(); \ + __ret = bfin_read32(((sport)->port.membase + OFFSET_RX)); \ + local_irq_enable(); \ + __ret; \ +}) #define SPORT_GET_RCR1(sport) bfin_read16(((sport)->port.membase + OFFSET_RCR1)) #define SPORT_GET_RCR2(sport) bfin_read16(((sport)->port.membase + OFFSET_RCR2)) #define SPORT_GET_RCLKDIV(sport) bfin_read16(((sport)->port.membase + OFFSET_RCLKDIV)) -- 1.6.0