2.6.35-stable review patch. If anyone has any objections, please let us know.
------------------
From: Yusuke Goda <yusuke.goda.sx@xxxxxxxxxxx>
commit b78d6c5f51935ba89df8db33a57bacb547aa7325 upstream.
Previously, it was possible for ack_mmc_irqs() to clear pending interrupt
bits in the CTL_STATUS register, even though the interrupt handler had not
been called. This was because of a race that existed when doing a
read-modify-write sequence on CTL_STATUS. After the read step in this
sequence, if an interrupt occurred (causing one of the bits in CTL_STATUS
to be set) the write step would inadvertently clear it.
Observed with the TMIO_STAT_RXRDY bit together with CMD53 on AR6002 and
BCM4318 SDIO cards in polled mode.
This patch eliminates this race by only writing to CTL_STATUS and clearing
the interrupts that were passed as an argument to ack_mmc_irqs()."
[matt@xxxxxxxxxxxxxxxxx: rewrote changelog]
Signed-off-by: Yusuke Goda <yusuke.goda.sx@xxxxxxxxxxx>
Acked-by: Magnus Damm <damm@xxxxxxxxxxxxx>
Tested-by: Arnd Hannemann <arnd@xxxxxxxxxx>"
Acked-by: Ian Molton <ian@xxxxxxxxxxxxxx>
Cc: Matt Fleming <matt@xxxxxxxxxxxxxxxxx>
Cc: Samuel Ortiz <sameo@xxxxxxxxxxxxxxx>
Cc: Paul Mundt <lethal@xxxxxxxxxxxx>
Cc: <linux-mmc@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
drivers/mmc/host/tmio_mmc.h | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
--- 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)
--
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