Messages in this thread | | | Date | Wed, 23 Sep 2015 17:34:13 -0700 | From | David Daney <> | Subject | Re: [PATCH v2 0/2] PCI: Add support for PCI Enhanced Allocation "BARs" |
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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.
> - 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(-) >
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