Aug 12, 2019 · Since the PCIe root complex is within the CPU, the CPU is the only concern when it comes to legacy PCI software compatibility (legacy PCI is need a PCIe to PCI bridge that will probably expose a configuration mechanism). In short, you can safely use the legacy PCI mechanism to access the first 256 bytes (per function) of the PCIe configuration ...

Jun 25, 2018 · It's a way of using the Intel processor's I/O address space to interface to the PCI bus configuration space mechanism. It can also be used on a PCIe system, because the PCIe host bridge component provides the same interface to PCIe devices. However, everything below the host bridge is implemented quite differently between PCI and PCIe.

Oct 8, 2022 · root@ampere:/boot# cat /proc/iomem|grep ECAM 23fff0000000-23ffffffffff : PCI ECAM 27fff0000000-27ffffffffff : PCI ECAM 2bfff0000000-2bffffffffff : PCI ECAM 2ffff0000000-2fffffffffff : PCI ECAM 3bfff0000000-3bffffffffff : PCI ECAM 3ffff0000000-3fffffffffff : PCI ECAM 63fff0000000-63ffffffffff : PCI ECAM 67fff0000000-67ffffffffff : PCI ECAM ...

May 29, 2020 · I am trying to implement bare metal PCIE device discovery on QEMU AArch64 virt device. I know, that ECAM area is mapped to 0x3f000000 memory address, and I expect to see there this table . But when I perform a reading of 4 bytes (MCFG signature) from 0x3f000000 address, I get a synchronous exception.

Mar 1, 2018 · The ECAM translator translates between a memory type transaction and a configuration space type transaction. The PCIe specification describes how a SINGLE ECAM translator implementation works to translate particular memory address bits in a targeted translation memory write or read, into a Configuration Space write or read. This works as follows:

Assuming it is, yes you can transfer data between a slave PCIe device and host using a DMA controller. I am working on a project which involves "PCIe-DMA" connected with the host over the PCIe bus. Really depends on your design and implementation. So in my case PCIe-DMA is itself a slave PCIe device on the target board connected to the host ...

Jun 14, 2011 · How to access PCIe configuration space? (ECAM) 2. accessing pci configuration space in real mode.

Mar 28, 2024 · In PCIe, Enhanced Configuration Access Mechanism (ECAM) is used to read/write Configuration Space. Memory map consists of base address, BDF values, Register Number. However, during enumeration, CPU do not know about the BDF of PCIe endpoint. (After enumeration, CPU assigns BDF for all PCIe endpoint. Am I right?)

Jul 22, 2020 · I've been diving deeper into how PCIe works in general, and I'm stuck at where many books and websites talk about PCIe configuration space. What I have learned so far is that for each of the assigned device with its BDF (bus-device-function bits), there corresponds a 4KB configuration space for that device, which includes the 64B region as below:

Feb 5, 2024 · pci-host-generic 6ffff0000000.pcie: host bridge /pcie@6ffff0000000 ranges: pci-host-generic 6ffff0000000.pcie: Parsing ranges property... pci-host-generic 6ffff0000000.pcie: MEM 0x6c0100000000..0x6fffdfffffff -> 0x6c0100000000 pci-host-generic 6ffff0000000.pcie: MEM 0x6c0004000000..0x6c0013ffffff -> 0x6c0004000000 pci-host-generic 6ffff0000000 ...