On Fri, Oct 02, 2015 at 08:16:48PM -0700, Yinghai Lu wrote: > On Fri, Oct 2, 2015 at 3:37 PM, David Daney <ddaney.cavm@xxxxxxxxx> wrote: > > From: David Daney <david.daney@xxxxxxxxxx> > > > > 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. > > > > The Enhanced Allocation ECN is publicly available here: > > https://www.pcisig.com/specifications/conventional/ECN_Enhanced_Allocation_23_Oct_2014_Final.pdf > > Looks like the EA will support more than just fixed address later. > > "Enhanced Allocation is an optional Conventional PCI Capability that > may be implemented by > Functions to indicate fixed (non reprogrammable) I/O and memory ranges > assigned to the > Function, as well as supporting new resource “type” definitions and > future extensibility to also > support reprogrammable allocations." > > so I would prefer to think more to make frame configurable to leave > space for that. > > Bjorn, > > I wonder if we need to revive the add-on resource support patchset > that i suggested couple years ago, > so we can extend it to support EA features. > > URL: https://lkml.org/lkml/2012/3/19/86 > > Thanks > > Yinghai This might be useful for fixed resources as well. For some BEI values, EA allows for an arbitrary number of EA entries. For PF & VF resource ranges, it allows 2 ranges. (one below the 4GB boundry, and one above). I don't think the current pci_dev struct can handle that many resources. -Sean -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
