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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: 8FJMoU34uqdVqVAKsGEiA/c1kAcwZyQ7ySD97SFcDCzcSeqhtx61Fcc7cybLQO+clCJWYmuoaquoVQwmVKyyr1jK5lUZlebPORd2PUz9ebIpYJn9zto3cD/wS8MWXGc2Lj8bJZzZb11J52HWLX+va3JNNoS27UHBntFLWxrHz10VjB/0ShHw5VPYqRPfkgDhnJN/fTfsZehuTLLZUHsEd47DKWNJwmdzyzVYR2eRYJLh81DUC5PO58o9J2iqCwNr0KVeOSVMB8FGJxTaZJCpYUisxRpacx60S+jLxRrGB2lN8GEDfVO6hi1vOgpYdpJm2QRJg0HQY1aEc9KSloFeWaCJlZ1uYHWLsNMeFrY0wxesYd89nZaigR+APUL1V97PxqDSKaprnnVSjxe1BsXOwYNlSVTPzbQSN2oGM4xjGomv2VycVYYOwytRJ5WIXiK/ X-OriginatorOrg: ti.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 24 Feb 2026 08:10:00.0088 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 919b9c47-a7d6-4dd5-faf6-08de737c1b1d X-MS-Exchange-CrossTenant-Id: e5b49634-450b-4709-8abb-1e2b19b982b7 X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=e5b49634-450b-4709-8abb-1e2b19b982b7;Ip=[198.47.23.195];Helo=[lewvzet201.ext.ti.com] X-MS-Exchange-CrossTenant-AuthSource: MN1PEPF0000F0DE.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: LV0PR10MB997589 On 24/02/26 00:25, Bjorn Helgaas wrote: > On Thu, Feb 19, 2026 at 12:15:11PM +0530, Aksh Garg wrote: >> PCIe r6.0, section 7.5.3.6 states that for multi-function devices, the >> Max Link Width and Max Link Speed fields in the Link Capabilities >> Register must report the same values for all functions. > > Please update the citations here and in the comment below to r7.0. > >> Currently, dw_pcie_setup() programs these fields only for physical >> function 0 (PF0) via dw_pcie_link_set_max_speed() and >> dw_pcie_link_set_max_link_width(). For multi-function endpoint >> configurations, PF1 and beyond retain their default values, violating >> the PCIe specification. >> >> Fix this by reading the Max Link Width and Max Link Speed fields from >> PF0's Link Capabilities Register after dw_pcie_setup() completes, >> then mirroring these values to all other physical functions. > > "PF" and "physical function" are terms that apply to SR-IOV, not to > ordinary functions of a multi-function device, so it's confusing to > use them here. Instead of "physical function 0" and "PF0", just refer > to "Function 0" as the spec does. > >> Fixes: 24ede430fa49 ("PCI: designware-ep: Add multiple PFs support for DWC") > > Sorry I missed it earlier; it's also the wrong term here in the > subject of 24ede430fa49, but it's too late to fix that. > >> Fixes: 89db0793c9f2 ("PCI: dwc: Add missing PCI_EXP_LNKCAP_MLW handling") >> Signed-off-by: Aksh Garg >> --- >> >> The link speed and width would be negotiated through PF0 during >> initialization that controls the link behaviour, hence it didn't broke >> the driver. However, the change is proposed just to make the driver >> compatible with the PCIe base specifications. >> >> The fix is implemented in pcie-designware-ep.c rather than modifying >> dw_pcie_setup() directly to keep pcie-designware.c independent of RC/EP >> specifics and maintain it as common code. >> >> Changes from v1 to v2: >> - Used FIELD_* macros >> >> v1: https://lore.kernel.org/all/20260202072758.101845-3-a-garg7@ti.com/ >> >> .../pci/controller/dwc/pcie-designware-ep.c | 23 ++++++++++++++++++- >> 1 file changed, 22 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c >> index 771241e1a2c9..6b9f90810fec 100644 >> --- a/drivers/pci/controller/dwc/pcie-designware-ep.c >> +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c >> @@ -1094,7 +1094,8 @@ static void dw_pcie_ep_init_non_sticky_registers(struct dw_pcie *pci) >> { >> struct dw_pcie_ep *ep = &pci->ep; >> u8 funcs = ep->epc->max_functions; >> - u8 func_no; >> + u32 ref_lnkcap, lnkcap; >> + u8 func_no, offset; >> >> dw_pcie_dbi_ro_wr_en(pci); >> >> @@ -1102,6 +1103,26 @@ static void dw_pcie_ep_init_non_sticky_registers(struct dw_pcie *pci) >> dw_pcie_ep_init_rebar_registers(ep, func_no); >> >> dw_pcie_setup(pci); >> + >> + /* >> + * PCIe r6.0, section 7.5.3.6 states that for multi-function endpoints, >> + * max link width and speed fields must report same values for all functions. >> + * However, dw_pcie_setup() programs these fields only for physical function 0. >> + * Hence, mirror these fields to all other physical functions as well. > > s/physical function 0/function 0/ > > Wrap this to fit in 80 columns like the rest of the file. > >> + */ >> + if (funcs > 1) { >> + offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP); >> + ref_lnkcap = dw_pcie_readl_dbi(pci, offset + PCI_EXP_LNKCAP); >> + ref_lnkcap = FIELD_GET(PCI_EXP_LNKCAP_MLW | PCI_EXP_LNKCAP_SLS, ref_lnkcap); >> + >> + for (func_no = 1; func_no < funcs; func_no++) { >> + offset = dw_pcie_ep_find_capability(ep, func_no, PCI_CAP_ID_EXP); >> + lnkcap = dw_pcie_ep_readl_dbi(ep, func_no, offset + PCI_EXP_LNKCAP); >> + FIELD_MODIFY(PCI_EXP_LNKCAP_MLW | PCI_EXP_LNKCAP_SLS, &lnkcap, ref_lnkcap); >> + dw_pcie_ep_writel_dbi(ep, func_no, offset + PCI_EXP_LNKCAP, lnkcap); > > Please wrap these too, it's not too hard to make these fit in 80 > columns like (most of) the rest of the file. > I will work on these feedbacks and post v3 series. Thanks! >> + } >> + } >> + >> dw_pcie_dbi_ro_wr_dis(pci); >> } >> >> -- >> 2.34.1 >>