From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3E15CD9D.62110C6@midrivers.com> Date: Fri, 03 Jan 2003 10:51:25 -0700 From: Mark Pilon MIME-Version: 1.0 To: "linuxppc-embedded@lists.linuxppc.org" Subject: DMA and caches -- 'correct handling'? Content-Type: text/plain; charset=us-ascii Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: this is a ppc405 -based controller question but has bearing on the right way to DMA under linux, in general: I have an application in which I'll be DMAing several megabytes from memory into a fifo; the data are cpu-created so I'd expect I'd need to flush the data cache prior to starting the DMA. is this implicitly done by any of the setup & start-dma calls or should I explicitly do this myself. also, give the sizeof the source buffer and the smallness of the 405 data cache, I'd expect I should flush the entire cache to memory (flush pending writes) rather than for the entire address range of the source buffer. thoughts? thanks, Mark -- Mark Pilon Minolta-QMS P.O. Box 37 325 Dawson County Road 227 Fallon, MT. 59326-0037 1-406-486-5539 (primary voice line) 1-406-853-0433 (cell) ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/