Oops... put the old linuxppc list on the CC, sorry!
On Thu, Jun 24, 2010 at 23:45, Kyle Moffett <k...@moffetthome.net> wrote: > Hello, > > I've got a new P2020 (32bit mpc85xx family) board I'm working on a > port for that includes 2 NOR flashes (128MB each) and a removable > SO-RDIMM of 2GB or 4GB. Unfortunately when I configure both flashes > in the device-tree off my elbc, Linux is completely unable to access > the second one because it attempts to ioremap() the entire virtual > address space of both FLASH chips. > > Even with only one flash chip enabled, there's a bit of a noticeable > performance degradation because the mapping consumes almost all of my > available vmalloc space and forces bounce-buffering for all my > HIGHMEM. > > It looks like the "of-flash" driver currently requires that the whole > chip be mapped in the kernel at once. I would much rather have a 50% > performance penalty on flash accesses (which are already very slow) > and regain most of the vmap space. > > So the question is, is there a way to convince the MTD layer to > iomap() only what it needs to access to do reads and writes? If not, > what changes would need to be made to MTD and/or "of-flash" to create > such functionality? > > Cheers, > Kyle Moffett > _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
