Re: [PATCH v2] powerpc: fsl_pci: Add forced PCI Agent enumeration

----- Original Message -----

From: "Scott Wood" <redacted>
Sent: Tuesday, August 26, 2014 3:52:56 PM

On Mon, 2014-08-25 at 18:54 -0500, Aaron Sierra wrote:

quoted

The following commit prevents the MPC8548E on the XPedite5200 PrPMC
module from enumerating its PCI/PCI-X bus:

    powerpc/fsl-pci: use 'Header Type' to identify PCIE mode

The previous patch prevents any Freescale PCI-X bridge from enumerating
the bus, if it is hardware strapped into Agent mode.

In PCI-X, the Host is responsible for driving the PCI-X initialization
pattern to devices on the bus, so that they know whether to operate in
conventional PCI or PCI-X mode as well as what the bus timing will be.
For a PCI-X PrPMC, the pattern is driven by the mezzanine carrier it is
installed onto. Therefore, PrPMCs are PCI-X Agents, but one per system
may still enumerate the bus.

This patch causes the device node of any PCI/PCI-X bridge strapped into
Agent mode to be checked for the fsl,pci-agent-force-enum property. If
the property is present in the node, the bridge will be allowed to
enumerate the bus.

Cc: Minghuan Lian <redacted>
Signed-off-by: Aaron Sierra <redacted>
---
 .../bindings/pci/fsl,pci-agent-force-enum.txt      | 27
 ++++++++++++++++++++++
 arch/powerpc/sysdev/fsl_pci.c                      |  3 ++-
 2 files changed, 29 insertions(+), 1 deletion(-)
 create mode 100644
 Documentation/devicetree/bindings/pci/fsl,pci-agent-force-enum.txt

diff --git
a/Documentation/devicetree/bindings/pci/fsl,pci-agent-force-enum.txt
b/Documentation/devicetree/bindings/pci/fsl,pci-agent-force-enum.txt
new file mode 100644
index 0000000..d8ac4a7

--- /dev/null
+++ b/Documentation/devicetree/bindings/pci/fsl,pci-agent-force-enum.txt

This ought to be part of a general fsl,pci binding, rather than its own
file.  Unfortunately there isn't such a binding yet, but let's call this
something like "fsl,pci.txt" anyway so that there's a place to add the
rest of the binding to.

Ok, no problem.
 

Also, CC devicetree@vger.kernel.org on all device tree patches.

Will do.

Otherwise it looks OK.

-Scott