[PATCH v2 3/3] PCI: ARM: add support for generic PCI host controller

On Thu, Feb 13, 2014 at 10:22 AM, Kumar Gala [off-list ref] wrote:

On Feb 13, 2014, at 5:07 AM, Will Deacon [off-list ref] wrote:

quoted

On Wed, Feb 12, 2014 at 09:51:48PM +0000, Kumar Gala wrote:

quoted

On Feb 12, 2014, at 2:16 PM, Will Deacon [off-list ref] wrote:

quoted

This patch adds support for a generic PCI host controller, such as a
firmware-initialised device with static windows or an emulation by
something such as kvmtool.

The controller itself has no configuration registers and has its address
spaces described entirely by the device-tree (using the bindings from
ePAPR). Both CAM and ECAM are supported for Config Space accesses.

Corresponding documentation is added for the DT binding.

Signed-off-by: Will Deacon <redacted>
---
.../devicetree/bindings/pci/arm-generic-pci.txt    |  51 ++++
drivers/pci/host/Kconfig                           |   7 +
drivers/pci/host/Makefile                          |   1 +
drivers/pci/host/pci-arm-generic.c                 | 318 +++++++++++++++++++++
4 files changed, 377 insertions(+)
create mode 100644 Documentation/devicetree/bindings/pci/arm-generic-pci.txt
create mode 100644 drivers/pci/host/pci-arm-generic.c

diff --git a/Documentation/devicetree/bindings/pci/arm-generic-pci.txt b/Documentation/devicetree/bindings/pci/arm-generic-pci.txt
new file mode 100644
index 000000000000..cc7a35ecfa2d
--- /dev/null
+++ b/Documentation/devicetree/bindings/pci/arm-generic-pci.txt

@@ -0,0 +1,51 @@
+* ARM generic PCI host controller
+
+Firmware-initialised PCI host controllers and PCI emulations, such as the
+virtio-pci implementations found in kvmtool and other para-virtualised
+systems, do not require driver support for complexities such as regulator and
+clock management. In fact, the controller may not even require the
+configuration of a control interface by the operating system, instead
+presenting a set of fixed windows describing a subset of IO, Memory and
+Configuration Spaces.
+
+Such a controller can be described purely in terms of the standardized device
+tree bindings communicated in pci.txt:
+
+- compatible     : Must be "arm,pci-cam-generic" or "arm,pci-ecam-generic"
+                   depending on the layout of configuration space (CAM vs
+                   ECAM respectively)

What's arm specific here?  I don't have a great suggestion, but seems odd
for this to be vendor prefixed with "arm".

Happy to change it, but I'm also struggling for names. Maybe "linux,..."?

I was thinking that as well, I'd say go with "linux,".

Just drop the prefix altogether.

I'm wondering if this should have host or rc in the name.

Rob