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authorSonic Zhang <sonic.zhang@analog.com>2010-03-09 12:25:28 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2010-05-21 09:34:27 -0700
commita5a420d207df40226afbf828c12bd9b4c6e058ef (patch)
treeaf4d91ce3f0f65728bbf6a7da86a5ee5e867292f /drivers/serial
parentd7dbf4ffee1c7a17e2e5b5f01efe76fbd1671db6 (diff)
downloadlinux-a5a420d207df40226afbf828c12bd9b4c6e058ef.tar.bz2
serial: bfin_sport_uart: work around anomaly 05000473 (make 32bit fifo read atomic)
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>
Diffstat (limited to 'drivers/serial')
-rw-r--r--drivers/serial/bfin_sport_uart.h16
1 files changed, 15 insertions, 1 deletions
diff --git a/drivers/serial/bfin_sport_uart.h b/drivers/serial/bfin_sport_uart.h
index abe03614e4df..9791fcc80a74 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))