Hi David, My response is inline. Let me know if you have any questions.
Thanks for taking a look, Sean On Wed, Sep 23, 2015 at 05:34:13PM -0700, David Daney wrote: > Hi Sean, > > Thanks for doing this, I think we will use it for Cavium ThunderX. > A couple of questions... > > > On 09/23/2015 03:27 PM, Sean O. Stalley wrote: > >PCI Enhanced Allocation is a new method of allocating MMIO & IO > >resources for PCI devices & bridges. It can be used instead > >of the traditional PCI method of using BARs. > > > >EA entries are hardware-initialized to a fixed address. > >Unlike BARs, regions described by EA are cannot be moved. > >Because of this, only devices which are permanently connected to > >the PCI bus can use EA. A removable PCI card must not use EA. > > > >This patchset adds support for using EA entries instead of BARs > >on Root Complex Integrated Endpoints. > > > >The Enhanced Allocation ECN is publicly available here: > >https://www.pcisig.com/specifications/conventional/ECN_Enhanced_Allocation_23_Oct_2014_Final.pdf > > > > > >Changes from V1: > > - Use generic PCI resource claim functions (instead of EA-specific > > functions) > > - Only add support for RCiEPs (instead of all devices). > > Why not all devices? The spec. allows for EA on devices behind bridges. The short answer is that adding support for EA bridges would be a much larger change. EA bridges can do some weird stuff, like fixing bus numbers & using resources not in the base+limit window. See the conversation I had with Bjorn on the original patchset for the details. [ https://lkml.org/lkml/2015/9/3/497 ] > > - Removed some debugging messages leftover from early testing. > > > > > >Sean O. Stalley (2): > > PCI: Add Enhanced Allocation register entries > > PCI: Add support for Enhanced Allocation devices > > > > drivers/pci/pci.c | 174 > > ++++++++++++++++++++++++++++++++++++++++++ > > drivers/pci/pci.h | 1 + > > drivers/pci/probe.c | 3 + > > include/uapi/linux/pci_regs.h | 40 +++++++++- > > 4 files changed, 217 insertions(+), 1 deletion(-) > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
