Shaveta, As long as all PCI I/O Protocol instances in the platform conform to UEFI spec, it can work.
Your original question was about how to tell that a handle has the PCI I/O Protocol produced By PCI Bus Driver or your emulation of PCI. If the PCI I/O Protocols are conformant, then It should not matter. Just write a PCI Device Driver that manages a PCI controller based on PCI Class code or Vendor ID/Device ID matching and it should work. Mike > -----Original Message----- > From: edk2-devel [mailto:[email protected]] On Behalf Of > Shaveta Leekha > Sent: Tuesday, May 3, 2016 3:27 AM > To: Laszlo Ersek <[email protected]> > Cc: [email protected] <[email protected]> > Subject: Re: [edk2] Two PCI IO protocols getting produced by same GUID, how > to open > correct one? > > > > -----Original Message----- > From: Laszlo Ersek [mailto:[email protected]] > Sent: Tuesday, May 03, 2016 1:15 PM > To: Shaveta Leekha <[email protected]> > Cc: [email protected] <[email protected]> > Subject: Re: [edk2] Two PCI IO protocols getting produced by same GUID, how > to open > correct one? > > On 05/03/16 08:54, Shaveta Leekha wrote: > > Hi, > > > > I have a scenario where two separate drivers are installing/producing "PCI > > IO" > protocol with same GUID (gEfiPciIoProtocolGuid). > > > > Where: > > > > (1) One of the PCI Io protocol instance is produced by > "MdeModulePkg/Bus/Pci/PciBus" driver for real PCI devices to use( like > E1000/NIC card > to use) > > > > (2) Other PCI Io protocol instance is produced by "Pci Emulation" layer > > created > for USB and SATA kind of controllers. This protocol (APIs) is intended to be > used by > USB and SATA controller drivers. > > > > Now when I use "OpenProtocol" in my "Platform specific Sata controller > > driver" using: > > > > Status = gBS->OpenProtocol ( > > Controller, > > &gEfiPciIoProtocolGuid, > > (VOID **) &PciIo, > > This->DriverBindingHandle, > > Controller, > > EFI_OPEN_PROTOCOL_GET_PROTOCOL > > ); > > > > How can I make sure that PCI Io protocol that is produced by "PciEmulation" > > layer > driver is getting opened? > > > > As "gEfiPciIoProtocolGuid" is same for both protocol instances. > > > > How to handle such scenarios? > > The UEFI spec forbids installing more than one protocol interface with the > same GUID on > the same handle. See > EFI_BOOT_SERVICES.InstallProtocolInterface(): > > [... The same GUID cannot be installed more than once onto the same > handle. If installation of a duplicate GUID on a handle is attempted, > an EFI_INVALID_PARAMETER will result. [...] > > EFI_INVALID_PARAMETER Protocol is already installed on the handle > specified by Handle. > > If you have two separate UEFI drivers that install PciIo interfaces on > handles, then > their EFI_DRIVER_BINDING_PROTOCOL.Supported() methods may report success only > on > distinct sets of handles. There must be no overlap. > > But, in any case, I think it's very unusual to have two drivers that produce > PciIo > interfaces. According to the "Driver Writer's Guide for UEFI 2.3.1" > (03/08/2012, > Version 1.01), section "18.2 PCI Bus Drivers": > > TIP: PCI Bus Driver customizations are *strongly discouraged* > because the PCI Bus Driver is designed to be conformant with > the /PCI Specification/. Instead, focus platform specific > customizations on the Root Bridge Driver that produced > EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL and its PCI Device Drivers. > > > [Shaveta] > Yes, it is un-usual and we had discussed over it also. > > So the scenario is: > ================ > On LS2080 platform, we have real PCI controllers that have E1000 card on > them(used for > networking purposes) And USB and SATA controllers are on-board. > So to provide SATA and USB, a PCIe emulation layer, a PCI IO protocol is > installed in > PciEmulation code. > PciEmulation code is very thin layer that simply produce PciRootBridgeIo > protocol and > hence PCI IO protocol, > Hence bypass the need of "real Pci Bus" code. > > Reference is taken from ArmJune platform code in EDK2. In it, it install : > (1) PCI IO protocol using "gEfiPciIoProtocolGuid" in > ArmPlatformPkg/ArmJunoPkg/Drivers/ArmJunoDxe/PciEmulation.c > (2) It also install " gEfiPciRootBridgeIoProtocolGuid" protocol, using which > "PciBusDxe" will produce PciIo protocol > > The same we are doing for our platform. > For real PCI controller, we have " installed Root Bridge PCI IO protocol with > gEfiPciRootBridgeIoProtocolGuid" > And for emulation layer, the code direcly install PCI IO protocol with > gEfiPciIoProtocolGuid" > > Regards, > Shaveta > > Laszlo > > _______________________________________________ > edk2-devel mailing list > [email protected] > https://lists.01.org/mailman/listinfo/edk2-devel _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
