The presence detect state (PDS) is normally a logical or of in-band and out-of-band presence. In 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. Signed-off-by: Alexandru Gagniuc <[email protected]> --- drivers/pci/hotplug/pciehp.h | 1 + drivers/pci/hotplug/pciehp_hpc.c | 12 +++++++++++- include/linux/pci.h | 1 + include/uapi/linux/pci_regs.h | 2 ++ 4 files changed, 15 insertions(+), 1 deletion(-) diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h index 506e1d923a1f..6f729ce4a7b9 100644 --- a/drivers/pci/hotplug/pciehp.h +++ b/drivers/pci/hotplug/pciehp.h @@ -98,6 +98,7 @@ struct controller { struct pcie_device *pcie; u32 slot_cap; /* capabilities and quirks */ + unsigned int inband_presence_disabled:1; u16 slot_ctrl; /* control register access */ struct mutex ctrl_lock; diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c index 7dd443aea5a5..f77dc7c38f9a 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -824,7 +824,7 @@ static inline void dbg_ctrl(struct controller *ctrl) struct controller *pcie_init(struct pcie_device *dev) { struct controller *ctrl; - u32 slot_cap, link_cap; + u32 slot_cap, slot_cap2, link_cap; u8 poweron; struct pci_dev *pdev = dev->port; struct pci_bus *subordinate = pdev->subordinate; @@ -846,6 +846,9 @@ struct controller *pcie_init(struct pcie_device *dev) if (pdev->is_thunderbolt) slot_cap |= PCI_EXP_SLTCAP_NCCS; + if (pdev->no_in_band_presence) + ctrl->inband_presence_disabled = 1; + ctrl->slot_cap = slot_cap; mutex_init(&ctrl->ctrl_lock); mutex_init(&ctrl->state_lock); @@ -882,6 +885,13 @@ struct controller *pcie_init(struct pcie_device *dev) FLAG(link_cap, PCI_EXP_LNKCAP_DLLLARC), pdev->broken_cmd_compl ? " (with Cmd Compl erratum)" : ""); + 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; + } + /* * If empty slot's power status is on, turn power off. The IRQ isn't * requested yet, so avoid triggering a notification with this command. diff --git a/include/linux/pci.h b/include/linux/pci.h index 65f1d8c2f082..9d08cdbca459 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -413,6 +413,7 @@ struct pci_dev { unsigned int non_compliant_bars:1; /* Broken BARs; ignore them */ unsigned int is_probed:1; /* Device probing in progress */ unsigned int link_active_reporting:1;/* Device capable of reporting link active */ + unsigned int no_in_band_presence:1; /* Device does not report in-band presence */ unsigned int no_vf_scan:1; /* Don't scan for VFs after IOV enablement */ pci_dev_flags_t dev_flags; atomic_t enable_cnt; /* pci_enable_device has been called */ diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h index e1e9888c85e6..5423dc476c77 100644 --- a/include/uapi/linux/pci_regs.h +++ b/include/uapi/linux/pci_regs.h @@ -597,6 +597,7 @@ #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 */ @@ -667,6 +668,7 @@ #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 0x0001 /* In-band PD Disable Supported */ #define PCI_EXP_SLTCTL2 56 /* Slot Control 2 */ #define PCI_EXP_SLTSTA2 58 /* Slot Status 2 */ -- 2.19.2
