From mboxrd@z Thu Jan 1 00:00:00 1970 From: swarren@wwwdotorg.org (Stephen Warren) Date: Wed, 16 Oct 2013 13:33:44 -0600 Subject: [PATCH] DMA: extend documentation to provide more API details In-Reply-To: References: <20131005190200.GZ12758@n2100.arm.linux.org.uk> <20131005233137.GA12758@n2100.arm.linux.org.uk> <20131006052029.GE2954@intel.com> <20131007111728.GM12758@n2100.arm.linux.org.uk> <20131007103936.GH2954@intel.com> Message-ID: <525EEA18.1010802@wwwdotorg.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 10/08/2013 07:34 PM, Dan Williams wrote: > On Mon, Oct 7, 2013 at 3:39 AM, Vinod Koul wrote: >> On Mon, Oct 07, 2013 at 12:17:28PM +0100, Russell King - ARM Linux wrote: ... >>> What may be better is to change the wording here: not DMA_SUCCESS but >>> DMA_COMPLETED. That doesn't imply that it has been successful, merely >>> that the DMA engine has finished with the transaction. >> >> Agreed that its not indication of success but of DMA completetion. I have seen >> cases where slave perhiphral got stuck while sending last FIFO but since DMA >> finished transferiing to FIFO it says complete. In that case, the DMA *has* completed. DMA is the transfer into the FIFO, not the handling of the FIFO content by the peripheral. >> Dan do you agree? > > Yes, it's an indication of completion, not necessarily success. Surely by definition, a DMA can't *complete* without being successful. If the DMA failed, then it didn't complete, but rather must have been aborted or error'd out, without completing the whole transfer.