From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <38C862A6.224DBDF3@embeddededge.com> Date: Thu, 09 Mar 2000 21:49:10 -0500 From: Dan Malek MIME-Version: 1.0 To: Greg Johnson CC: Linux PPC Mailing List Subject: Re: User buffers and cache flushing. References: <20000310010235.6B0D3355C8@elph.research.canon.com.au> Content-Type: text/plain; charset=us-ascii Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: Greg Johnson wrote: > ....Since I > am not wanting to be double handling this data, and the data will > most likely be fragmented in memory, That's no problem, CPM buffer descriptors are made for that. > ....and call flush_dcache_range on each of these fragments. Depends upon how the data is handled. In some cases I find it is faster to just map the pages uncached and skip the cache push. Do some system design and analysis to determine what works best. > Have I overlooked anything? (other than the lack of support for IDMA > currently in the MPC8xx kernel) This is pretty trivial, considering all CPM devices use the same DMA engine as IDMA. Take an existing driver, rip the guts of data comm out of it, and you nearly have the IDMA driver. -- Dan ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/