From 7144257ec049aa597dd6a17a7f30d5b1ae098d2d Mon Sep 17 00:00:00 2001 From: Alexandru Gagniuc Date: Mon, 27 Jul 2020 11:11:30 -0400 Subject: [PATCH] PCI: pciehp: Disable in-band presence detect when possible task #29600094 commit 202853595e53f981c86656c49fc1cc1e3620f558 upstream. Backport summary: for 4.19 kernel ICX PCIe Gen4 support. The presence detect state (PDS) is normally a logical OR of in-band and out-of-band (OOB) presence detect. As of PCIe 4.0, there is the option to disable in-band presence so that the PDS bit always reflects the state of the out-of-band presence. The recommendation of the PCIe spec is to disable in-band presence whenever supported (PCIe r5.0, appendix I implementation note): Due to architectural issues, the in-band (Physical-Layer-based) portion of the PD mechanism is deprecated for use with async hot-plug. One issue is that in-band PD as architected does not detect adapter removal during certain LTSSM states, notably the L1 and Disabled States. Another issue is that when both in-band and OOB PD are being used together, the Presence Detect State bit and its associated interrupt mechanism always reflect the logical OR of the inband and OOB PD states, and with some hot-plug hardware configurations, it is important for software to detect and respond to in-band and OOB PD events independently. If OOB PD is being used and the associated DSP supports In-Band PD Disable, it is recommended that the In-Band PD Disable bit be Set, and the Presence Detect State bit and its associated interrupt mechanism be used exclusively for OOB PD. As a substitute for in-band PD with async hot-plug, the reference model uses either the DPC or the DLL Link Active mechanism. Link: https://lore.kernel.org/r/20191025190047.38130-2-stuart.w.hayes@gmail.com [bhelgaas: move PCI_EXP_SLTCAP2 read earlier & print PCI_EXP_SLTCAP2_IBPD value (suggested by Lukas)] Signed-off-by: Alexandru Gagniuc Signed-off-by: Bjorn Helgaas Reviewed-by: Andy Shevchenko Reviewed-by: Lukas Wunner (cherry picked from commit 202853595e53f981c86656c49fc1cc1e3620f558) Signed-off-by: Ethan Zhao Conflicts: drivers/pci/hotplug/pciehp.h drivers/pci/hotplug/pciehp_hpc.c Signed-off-by: Artie Ding Acked-by: Caspar Zhang --- drivers/pci/hotplug/pciehp.h | 1 + drivers/pci/hotplug/pciehp_hpc.c | 12 ++++++++++-- include/uapi/linux/pci_regs.h | 2 ++ 3 files changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h index 4e09ef88bcc2..4b81b73bebbb 100644 --- a/drivers/pci/hotplug/pciehp.h +++ b/drivers/pci/hotplug/pciehp.h @@ -109,6 +109,7 @@ struct slot { struct controller { struct mutex ctrl_lock; struct pcie_device *pcie; + unsigned int inband_presence_disabled:1; struct rw_semaphore reset_lock; struct slot *slot; wait_queue_head_t queue; diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c index 85e79b687f54..ba93084f510a 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -842,8 +842,8 @@ static inline void dbg_ctrl(struct controller *ctrl) struct controller *pcie_init(struct pcie_device *dev) { struct controller *ctrl; - u32 slot_cap, link_cap; u8 occupied, poweron; + u32 slot_cap, slot_cap2, link_cap; struct pci_dev *pdev = dev->port; ctrl = kzalloc(sizeof(*ctrl), GFP_KERNEL); @@ -870,6 +870,13 @@ struct controller *pcie_init(struct pcie_device *dev) init_waitqueue_head(&ctrl->queue); dbg_ctrl(ctrl); + pcie_capability_read_dword(pdev, PCI_EXP_SLTCAP2, &slot_cap2); + if (slot_cap2 & PCI_EXP_SLTCAP2_IBPD) { + pcie_write_cmd_nowait(ctrl, PCI_EXP_SLTCTL_IBPD_DISABLE, + PCI_EXP_SLTCTL_IBPD_DISABLE); + ctrl->inband_presence_disabled = 1; + } + /* Check if Data Link Layer Link Active Reporting is implemented */ pcie_capability_read_dword(pdev, PCI_EXP_LNKCAP, &link_cap); @@ -879,7 +886,7 @@ struct controller *pcie_init(struct pcie_device *dev) PCI_EXP_SLTSTA_MRLSC | PCI_EXP_SLTSTA_CC | PCI_EXP_SLTSTA_DLLSC | PCI_EXP_SLTSTA_PDC); - ctrl_info(ctrl, "Slot #%d AttnBtn%c PwrCtrl%c MRL%c AttnInd%c PwrInd%c HotPlug%c Surprise%c Interlock%c NoCompl%c LLActRep%c%s\n", + ctrl_info(ctrl, "Slot #%d AttnBtn%c PwrCtrl%c MRL%c AttnInd%c PwrInd%c HotPlug%c Surprise%c Interlock%c NoCompl%c IbPresDis%c LLActRep%c%s\n", (slot_cap & PCI_EXP_SLTCAP_PSN) >> 19, FLAG(slot_cap, PCI_EXP_SLTCAP_ABP), FLAG(slot_cap, PCI_EXP_SLTCAP_PCP), @@ -890,6 +897,7 @@ struct controller *pcie_init(struct pcie_device *dev) FLAG(slot_cap, PCI_EXP_SLTCAP_HPS), FLAG(slot_cap, PCI_EXP_SLTCAP_EIP), FLAG(slot_cap, PCI_EXP_SLTCAP_NCCS), + FLAG(slot_cap2, PCI_EXP_SLTCAP2_IBPD), FLAG(link_cap, PCI_EXP_LNKCAP_DLLLARC), pdev->broken_cmd_compl ? " (with Cmd Compl erratum)" : ""); diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h index 18161ee633a9..f8748664f3d3 100644 --- a/include/uapi/linux/pci_regs.h +++ b/include/uapi/linux/pci_regs.h @@ -603,6 +603,7 @@ #define PCI_EXP_SLTCTL_PWR_OFF 0x0400 /* Power Off */ #define PCI_EXP_SLTCTL_EIC 0x0800 /* Electromechanical Interlock Control */ #define PCI_EXP_SLTCTL_DLLSCE 0x1000 /* Data Link Layer State Changed Enable */ +#define PCI_EXP_SLTCTL_IBPD_DISABLE 0x4000 /* In-band PD disable */ #define PCI_EXP_SLTSTA 26 /* Slot Status */ #define PCI_EXP_SLTSTA_ABP 0x0001 /* Attention Button Pressed */ #define PCI_EXP_SLTSTA_PFD 0x0002 /* Power Fault Detected */ @@ -673,6 +674,7 @@ #define PCI_EXP_LNKSTA2 50 /* Link Status 2 */ #define PCI_CAP_EXP_ENDPOINT_SIZEOF_V2 52 /* v2 endpoints with link end here */ #define PCI_EXP_SLTCAP2 52 /* Slot Capabilities 2 */ +#define PCI_EXP_SLTCAP2_IBPD 0x00000001 /* In-band PD Disable Supported */ #define PCI_EXP_SLTCTL2 56 /* Slot Control 2 */ #define PCI_EXP_SLTSTA2 58 /* Slot Status 2 */ -- GitLab