<font style="font-size: 10pt; font-family: Tahoma;"><font style="font-size: 10pt; font-family: Tahoma;"><font style="font-size: 10pt; font-family: Tahoma;"><font style="font-size: 10pt; font-family: Tahoma;"><font style="font-size: 10pt; font-family: Tahoma;">1. BAT2 in linux is set to WIMG=0010, and covers
all 64M<br>2. PEX_DEVICE_CONTROL in PCI-E Config Space (0x54):
0x1020<br>3. PEX_xDMA_CTRL is set to <span></span>0x00000401 at the initiation of the
DMA.<br>4. OWAR0 is set to 0xFFFFF005, so NSNP is 0.<br>5.
The DMA descriptor (randomly chosen when I hit a trigger...just ignore
the size...) contains 0002AFF3 at offset 0, so nosnoops are cleared.</font></font></font></font></font><font style="font-size: 10pt; font-family: Tahoma;"><font style="font-size: 10pt; font-family: Tahoma;"><font style="font-size: 10pt; font-family: Tahoma;"><font style="font-size: 10pt; font-family: Tahoma;"> <br>
<br>Core is 400MHz, and CSB is 133MHz.</font></font></font></font><br><font color="#888888"><br>- Ben<br></font><br><div class="gmail_quote">On Thu, Mar 5, 2009 at 11:27 PM, Liu Dave-R63238 <span dir="ltr"><<a href="mailto:DaveLiu@freescale.com">DaveLiu@freescale.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">and what settings is DMA description bit 3?<br>
<div class="im"><br>
> -----Original Message-----<br>
> From: linuxppc-dev-bounces+daveliu=<a href="http://freescale.com" target="_blank">freescale.com</a>@<a href="http://ozlabs.org" target="_blank">ozlabs.org</a><br>
> [mailto:<a href="mailto:linuxppc-dev-bounces%2Bdaveliu">linuxppc-dev-bounces+daveliu</a>=<a href="http://freescale.com" target="_blank">freescale.com</a>@<a href="http://ozlabs.org" target="_blank">ozlabs.org</a>]<br>
</div><div><div></div><div class="h5">> On Behalf Of Liu Dave-R63238<br>
> Sent: Friday, March 06, 2009 1:22 PM<br>
> To: Ben Menchaca; <a href="mailto:linuxppc-dev@ozlabs.org">linuxppc-dev@ozlabs.org</a><br>
> Subject: RE: 83xx: Marking or Allocating Pages as Cache-Inhibited<br>
><br>
> Did you enable the snoop bit at PEX_WDMA_CTRL[SNOOP] and<br>
> PEX_RDMA_CTRL[SNOOP]?<br>
><br>
> What is the freq settings? CORE/CSB bus.<br>
><br>
> Thanks, Dave<br>
><br>
> ________________________________<br>
><br>
> From: linuxppc-dev-bounces+daveliu=<a href="http://freescale.com" target="_blank">freescale.com</a>@<a href="http://ozlabs.org" target="_blank">ozlabs.org</a><br>
> [mailto:<a href="mailto:linuxppc-dev-bounces%2Bdaveliu">linuxppc-dev-bounces+daveliu</a>=<a href="http://freescale.com" target="_blank">freescale.com</a>@<a href="http://ozlabs.org" target="_blank">ozlabs.org</a>]<br>
> On Behalf Of Ben Menchaca<br>
> Sent: Friday, March 06, 2009 12:33 PM<br>
> To: <a href="mailto:linuxppc-dev@ozlabs.org">linuxppc-dev@ozlabs.org</a><br>
> Subject: 83xx: Marking or Allocating Pages as Cache-Inhibited<br>
><br>
><br>
> I am working on a Freescale 8314e design, and the<br>
> embedded device is configured as a PCI-e endpoint running a<br>
> 2.6.27-5 kernel. For context, we have written a kernel<br>
> module which, among other things, uses the RDMA/WDMA engine<br>
> in the PCI-e IP block. On the host side, these DMAs are<br>
> coherent. However, on the embedded side, things are quite a<br>
> bit less rosy; we must manually flush/invalidate cache lines<br>
> for WDMA/RDMAs to occur successfully. After speaking with<br>
> (several) FAEs at Freescale, we believe there is a<br>
> configuration issue that is the cause, but we have yet to<br>
> have anyone successfully point to it.<br>
><br>
> Disabling the data cache altogether resolves the issue<br>
> entirely, but of course, also completely tanks performance.<br>
> As a temporary workaround, I would like to simply mark the<br>
> pages (obtained currently via dma_alloc_coherent) involved as<br>
> cache-inhibited. I have attempted to do this via some<br>
> snippets remaining in fec.c (va_to_pte, uncache_pte to set<br>
> _PAGE_NO_CACHE, flush_tlb_page, then unmap_pte), but this is<br>
> almost certainly braindead; va_to_pte is not a part of the<br>
> 83xx source, as far as I can tell; 8xx only.<br>
><br>
> A quick pointer in the correct direction for marking<br>
> pages as cache-inhibited on a 2.6.27-5 kernel would be<br>
> appreciated, or if my approach to a workaround is flawed, a<br>
> pointer to the correct way would be great.<br>
><br>
> Ben Menchaca<br>
><br>
><br>
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><br>
><br>
</blockquote></div><br>