Messages in this thread | | | From | Marc Pignat <> | Subject | Re: [PATCH 6/6] atmel_serial: Add DMA support | Date | Wed, 23 Jan 2008 13:30:32 +0100 |
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Hi!
On Wednesday 23 January 2008, Haavard Skinnemoen wrote: > On Tue, 22 Jan 2008 17:52:43 +0100 > Marc Pignat <marc.pignat@hevs.ch> wrote: > > > Hi! > > > > I removed linux-arm-kernel@lists.arm.linux.org.uk from cc, it is a > > subscriber-only list. > > Right. Does that mean I shouldn't Cc it on patches? extract from the linux-arm-kernel 'Mailing List Etiquette': 10. Cross-posting between linux-arm* lists and other lists. [[40]rmk] Please do not do this. Subscribers on other lists may not be subscribed to the linux-arm lists, so when they try to reply to such a message, they will receive a bounce. This is deemed by others to be rude behaviour on the part of the person who originally cross-posted. > > > On Tuesday 22 January 2008, Haavard Skinnemoen wrote: > > > From: Chip Coldwell <coldwell@redhat.com> > > ... > > > @@ -47,6 +50,11 @@ > > > > > > #include "atmel_serial.h" > > > > > > +#define SUPPORT_PDC > > > +#define PDC_BUFFER_SIZE (L1_CACHE_BYTES << 3) > > > +#warning "Revisit" > > why add this warning? > > Dunno. I suppose the PDC_BUFFER_SIZE and/or PDC_RX_TIMEOUT definitions > needs to be revisited? Chip? I just think there is no need to warn, even if definitions are sub-optimal.
> > I don't really understand why the buffer size depends on the cache line > size either. Why don't we just set it to something nice and large, like > 512 (actually 1024 since there are two buffers), and be done with it? Probably for dma safety/performance, The PDC buffer start should be aligned to cache line, and the size be a multiple of cache line size.
> > And while we're at it, might as well move the SUPPORT_PDC definition > into Kconfig where it belongs... For me there is no need to disbable pdc support once working. PDC can be enabled/disabled in the board setup code. -> simply remove this definition.
Regards
Marc
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