tree cc9425cd553b187bfee1495b89483fed5fd1910f
parent a9af316c83e3d81e26985193ffafdf143b327c07
author Ludovic Desroches <ludovic.desroches@atmel.com> 1457601475 +0100
committer Vinod Koul <vinod.koul@intel.com> 1457607756 +0530

dmaengine: at_xdmac: fix residue computation

When computing the residue we need two pieces of information: the current
descriptor and the remaining data of the current descriptor. To get
that information, we need to read consecutively two registers but we
can't do it in an atomic way. For that reason, we have to check manually
that current descriptor has not changed.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Suggested-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Reported-by: David Engraf <david.engraf@sysgo.com>
Tested-by: David Engraf <david.engraf@sysgo.com>
Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel
eXtended DMA Controller driver")
Cc: stable@vger.kernel.org #4.1 and later
Signed-off-by: Vinod Koul <vinod.koul@intel.com>