linux-kernel - [PATCH][bfin-sport-uart] Walk around RX underflow hardware issue in 32-bit SPORT RX reading

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <1253264747.22138.2.camel@eight.analog.com>
Date:	Fri, 18 Sep 2009 17:05:47 +0800
From:	sonic zhang <sonic.adi@...il.com>
To:	Alan Cox <alan@...rguk.ukuu.org.uk>,
	Linux Kernel <linux-kernel@...r.kernel.org>,
	Linux Serial <linux-serial@...r.kernel.org>
Subject: [PATCH][bfin-sport-uart] Walk around RX underflow hardware issue
	in 32-bit SPORT RX reading

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 <sonic.zhang@...log.com>
---
 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



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/