linux-kernel - [PATCH] schemas: pci: Document PCIe T_POWER

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20251106113951.844312-1-krishna.chundru@oss.qualcomm.com>
Date: Thu,  6 Nov 2025 17:09:51 +0530
From: Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>
To: andersson@...nel.org, robh@...nel.org, manivannan.sadhasivam@...aro.org,
        krzk@...nel.org, helgaas@...nel.org
Cc: linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
        lpieralisi@...nel.org, kw@...ux.com, conor+dt@...nel.org,
        linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
        devicetree-spec@...r.kernel.org, quic_vbadigan@...cinc.com,
        krishna.chundru@....qualcomm.com
Subject: [PATCH] schemas: pci: Document PCIe T_POWER_ON

>From PCIe r6, sec 5.5.4 & sec 5.5.5 T POWER_ON is the minimum amount
of time that each component must wait in L1.2.Exit after sampling CLKREQ#
asserted before actively driving the interface to ensure no device is ever
actively driving into an unpowered component and these values are based on
the components and AC coupling capacitors used in the connection linking
the two components.

Certain controllers may need to program this before enumeration, such
controllers can use this property to program it.

Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>
---
 dtschema/schemas/pci/pci-bus-common.yaml | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/dtschema/schemas/pci/pci-bus-common.yaml b/dtschema/schemas/pci/pci-bus-common.yaml
index 5257339..bbe5510 100644
--- a/dtschema/schemas/pci/pci-bus-common.yaml
+++ b/dtschema/schemas/pci/pci-bus-common.yaml
@@ -152,6 +152,15 @@ properties:
       This property is invalid in host bridge nodes.
     maxItems: 1
 
+  t-power-on-us:
+    description:
+      The minimum amount of time that each component must wait in
+      L1.2.Exit after sampling CLKREQ# asserted before actively driving
+      the interface to ensure no device is ever actively driving into an
+      unpowered component. This value is based on the components and AC
+      coupling capacitors used in the connection linking the two
+      components(PCIe r6.0, sec 5.5.4).
+
   supports-clkreq:
     description:
       If present this property specifies that CLKREQ signal routing exists from
-- 
2.34.1