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Subject[PATCH 01/25] serial: bfin_sport_uart: work around anomaly 05000473 (make 32bit fifo read atomic)
Date
From: Sonic Zhang <sonic.zhang@analog.com>

We cannot let a 32-bit RX FIFO read be interrupted otherwise a fake RX
underflow error might be generated.

URL: http://blackfin.uclinux.org/gf/tracker/5145

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/serial/bfin_sport_uart.h | 16 +++++++++++++++-
1 files changed, 15 insertions(+), 1 deletions(-)

diff --git a/drivers/serial/bfin_sport_uart.h b/drivers/serial/bfin_sport_uart.h
index abe0361..9791fcc 100644
--- a/drivers/serial/bfin_sport_uart.h
+++ b/drivers/serial/bfin_sport_uart.h
@@ -37,7 +37,21 @@
#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))
+/*
+ * If another interrupt fires while doing a 32-bit read from RX FIFO,
+ * a fake RX underflow error will be generated. So disable interrupts
+ * to prevent interruption while reading the FIFO.
+ */
+#define SPORT_GET_RX32(sport) \
+({ \
+ unsigned int __ret; \
+ if (ANOMALY_05000473) \
+ local_irq_disable(); \
+ __ret = bfin_read32((sport)->port.membase + OFFSET_RX); \
+ if (ANOMALY_05000473) \
+ 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))
--
1.7.0.3


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