[PATCH] tmio_mmc: Make ack_mmc_irqs() write-only

Yusuke Goda
2010-07-20T07:53:50Z

This patch updates ack_mmc_irqs() to acknowledge using write instead
of read-modify-write. Without this fix the old read-modify-write
implementation may acknowledge interrupt sources by mistake. The
driver may if so lock-up waiting forever for an interrupt that will
never come. Observed with the TMIO_STAT_RXRDY bit together with CMD53
on AR6002 and BCM4318 SDIO cards in polled mode.

Signed-off-by: Yusuke Goda <yusuke.goda.sx@renesas.com>
---
drivers/mmc/host/tmio_mmc.h | 5 +----
1 files changed, 1 insertions(+), 4 deletions(-)

diff --git a/drivers/mmc/host/tmio_mmc.h b/drivers/mmc/host/tmio_mmc.h
index 64f7d5d..7944604 100644
--- a/drivers/mmc/host/tmio_mmc.h
+++ b/drivers/mmc/host/tmio_mmc.h
@@ -82,10 +82,7 @@

#define ack_mmc_irqs(host, i) \
do { \
- u32 mask;\
- mask = sd_ctrl_read32((host), CTL_STATUS); \
- mask &= ~((i) & TMIO_MASK_IRQ); \
- sd_ctrl_write32((host), CTL_STATUS, mask); \
+ sd_ctrl_write32((host), CTL_STATUS, ~(i)); \
} while (0)

--
1.7.0