[PATCH 01/25] serial: bfin_sport_uart: work around anomaly 05000473 (make 32bit fifo read atomic)
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From: Greg Kroah-Hartman on 21 May 2010 13:10 From: Sonic Zhang <sonic.zhang(a)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(a)analog.com> Signed-off-by: Mike Frysinger <vapier(a)gentoo.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |