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X-OriginatorOrg: ti.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 29 Jan 2026 09:18:21.9862 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 93567ec0-be6a-4f73-e2a0-08de5f175957 X-MS-Exchange-CrossTenant-Id: e5b49634-450b-4709-8abb-1e2b19b982b7 X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=e5b49634-450b-4709-8abb-1e2b19b982b7;Ip=[198.47.21.194];Helo=[flwvzet200.ext.ti.com] X-MS-Exchange-CrossTenant-AuthSource: BN3PEPF0000B373.namprd21.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS7PR10MB7190 Content-Type: text/plain; charset="utf-8" PCIe r6.0, section 7.9.15 requires PTM capability in exactly one function to control all PTM-capable functions. This makes PTM registers controller-level rather than per-function. Add a comment explaining why PTM capability registers are accessed using the standard DBI accessors instead of func_no indexed per-function accessors. Suggested-by: Niklas Cassel Signed-off-by: Aksh Garg Reviewed-by: Niklas Cassel --- Changes from v3 to v4: - Rebase Changes from v2 to v3: - Fixed the suggested nits v3: https://lore.kernel.org/all/20260127085010.446116-4-a-garg7@ti.com/ v2: https://lore.kernel.org/all/20260122082538.309122-4-a-garg7@ti.com/ drivers/pci/controller/dwc/pcie-designware-ep.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/= controller/dwc/pcie-designware-ep.c index b9a234b47aab..aa0c1dac297c 100644 --- a/drivers/pci/controller/dwc/pcie-designware-ep.c +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c @@ -1183,6 +1183,16 @@ int dw_pcie_ep_init_registers(struct dw_pcie_ep *ep) if (ep->ops->init) ep->ops->init(ep); =20 + /* + * PCIe r6.0, section 7.9.15 states that for endpoints that support PTM, + * this capability structure is required in exactly one function, which + * controls the PTM behavior of all PTM capable functions. This indicates + * the PTM capability structure represents controller-level registers + * rather than per-function registers. + * + * Therefore, PTM capability registers are configured using the standard = DBI + * accessors, instead of func_no indexed per-function accessors. + */ ptm_cap_base =3D dw_pcie_find_ext_capability(pci, PCI_EXT_CAP_ID_PTM); =20 /* --=20 2.34.1