From ffb4d602623aef9eb813a35b87b20854c030a2ec Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Wed, 24 Jun 2015 16:05:54 -0500 Subject: [PATCH] PCI: Add pcie_downstream_port() (true for Root and Switch Downstream Ports) As used in the PCIe spec, "Downstream Port" includes both Root Ports and Switch Downstream Ports. We sometimes checked for PCI_EXP_TYPE_DOWNSTREAM when we should have checked for PCI_EXP_TYPE_ROOT_PORT or PCI_EXP_TYPE_DOWNSTREAM. For a Root Port without a slot, the effect of this was that using pcie_capability_read_word() to read PCI_EXP_SLTSTA returned zero instead of showing the Presence Detect State bit hardwired to one as the PCIe Spec, r3.0, sec 7.8, requires. (This read is completed in software because previous PCIe spec versions didn't require PCI_EXP_SLTSTA to exist at all.) Nothing in the kernel currently depends on this (pciehp only reads PCI_EXP_SLTSTA on ports with slots), so this is a cleanup and not a functional change. Add a pcie_downstream_port() helper function and use it. Signed-off-by: Bjorn Helgaas Acked-by: Rafael J. Wysocki --- drivers/pci/access.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) diff --git a/drivers/pci/access.c b/drivers/pci/access.c index d9b64a175990..5465b005220c 100644 --- a/drivers/pci/access.c +++ b/drivers/pci/access.c @@ -531,6 +531,14 @@ static inline int pcie_cap_version(const struct pci_dev *dev) return pcie_caps_reg(dev) & PCI_EXP_FLAGS_VERS; } +static bool pcie_downstream_port(const struct pci_dev *dev) +{ + int type = pci_pcie_type(dev); + + return type == PCI_EXP_TYPE_ROOT_PORT || + type == PCI_EXP_TYPE_DOWNSTREAM; +} + bool pcie_cap_has_lnkctl(const struct pci_dev *dev) { int type = pci_pcie_type(dev); @@ -546,10 +554,7 @@ bool pcie_cap_has_lnkctl(const struct pci_dev *dev) static inline bool pcie_cap_has_sltctl(const struct pci_dev *dev) { - int type = pci_pcie_type(dev); - - return (type == PCI_EXP_TYPE_ROOT_PORT || - type == PCI_EXP_TYPE_DOWNSTREAM) && + return pcie_downstream_port(dev) && pcie_caps_reg(dev) & PCI_EXP_FLAGS_SLOT; } @@ -628,10 +633,9 @@ int pcie_capability_read_word(struct pci_dev *dev, int pos, u16 *val) * State bit in the Slot Status register of Downstream Ports, * which must be hardwired to 1b. (PCIe Base Spec 3.0, sec 7.8) */ - if (pci_is_pcie(dev) && pos == PCI_EXP_SLTSTA && - pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM) { + if (pci_is_pcie(dev) && pcie_downstream_port(dev) && + pos == PCI_EXP_SLTSTA) *val = PCI_EXP_SLTSTA_PDS; - } return 0; } @@ -657,10 +661,9 @@ int pcie_capability_read_dword(struct pci_dev *dev, int pos, u32 *val) return ret; } - if (pci_is_pcie(dev) && pos == PCI_EXP_SLTCTL && - pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM) { + if (pci_is_pcie(dev) && pcie_downstream_port(dev) && + pos == PCI_EXP_SLTSTA) *val = PCI_EXP_SLTSTA_PDS; - } return 0; } -- 2.20.1