Re: [PATCH V5 07/16] dt-bindings: PCI: designware: Add binding for CDM register check

From: Vidya Sagar
Date: Tue May 07 2019 - 04:26:45 EST

On 4/26/2019 8:02 PM, Rob Herring wrote:
On Wed, Apr 24, 2019 at 10:49:55AM +0530, Vidya Sagar wrote:
Add support to enable CDM (Configuration Dependent Module) registers check
for any data corruption. CDM registers include standard PCIe configuration
space registers, Port Logic registers and iATU and DMA registers.
Refer Section S.4 of Synopsys DesignWare Cores PCI Express Controller Databook
Version 4.90a

Signed-off-by: Vidya Sagar <vidyas@xxxxxxxxxx>
Changes since [v4]:
* None

Changes since [v3]:
* None

Changes since [v2]:
* Changed flag name from 'cdm-check' to 'enable-cdm-check'
* Added info about Port Logic and DMA registers being part of CDM

Changes since [v1]:
* This is a new patch in v2 series

Documentation/devicetree/bindings/pci/designware-pcie.txt | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/Documentation/devicetree/bindings/pci/designware-pcie.txt b/Documentation/devicetree/bindings/pci/designware-pcie.txt
index 5561a1c060d0..85b872c42a9f 100644
--- a/Documentation/devicetree/bindings/pci/designware-pcie.txt
+++ b/Documentation/devicetree/bindings/pci/designware-pcie.txt
@@ -34,6 +34,11 @@ Optional properties:
- clock-names: Must include the following entries:
- "pcie"
- "pcie_bus"
+- enable-cdm-check: This is a boolean property and if present enables

This needs a vendor prefix.
Why only for this? Since this whole file is for Synopsys DesignWare core based PCIe IP,
I thought there is specific prefix required. Am I wrong? Also, CDM checking is a feature
of IP and DWC based implementations can choose either to enable this feature at hardware level
or not. And whoever enabled it at hardware level (like Tegra194) can set this flag to
enable corresponding software support.

+ automatic checking of CDM (Configuration Dependent Module) registers
+ for data corruption. CDM registers include standard PCIe configuration
+ space registers, Port Logic registers, DMA and iATU (internal Address
+ Translation Unit) registers.
RC mode:
- num-viewport: number of view ports configured in hardware. If a platform
does not specify it, the driver assumes 2.