omap_hsmmc: improve interrupt synchronisation
The following changes were needed:
- do not use in_interrupt() because it will not work
with threaded interrupts
In addition, the following improvements were made:
- ensure DMA is unmapped only after the final DMA interrupt
- ensure a request is completed only after the final DMA interrupt
- disable controller interrupts when a request is not in progress
- remove the spin-lock protecting the start of a new request from
an unexpected interrupt because the locking was complicated and
a 'req_in_progress' flag suffices (since the spin-lock only defers
the unexpected interrupts anyway)
- instead use the spin-lock to protect the MMC interrupt handler
from the DMA interrupt handler
- remove the semaphore preventing DMA from being started while
the previous DMA is still in progress - the other changes make that
impossible, so it is now a BUG_ON condition
- ensure the controller interrupt status is clear before exiting
the interrrupt handler
In general, these changes make the code safer but do not fix any specific
bugs so backporting is not necessary.
Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
Tested-by: Venkatraman S <svenkatr@ti.com>
Acked-by: Madhusudhan Chikkature <madhu.cr@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 file changed