...actually triggers the error message. That's because the
dw_mci_enable_sdio_irq() unsafely does a read-modify-write of the
INTMASK register.
We can't just use the standard host->lock since that lock is not irq
safe and mmc_signal_sdio_irq() (called from interrupt context) calls
dw_mci_enable_sdio_irq(). Add a new irq-safe lock to protect INTMASK.
An alternate solution to this is to punt mmc_signal_sdio_irq() to the
tasklet and then protect INTMASK modifications by the standard host
lock. This seemed like a bit more of a high-latency change.
Reported-by: Bing Zhao <bzhao@marvell.com> Signed-off-by: Doug Anderson <dianders@chromium.org> Reviewed-by: James Hogan <james.hogan@imgtec.com> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>