From ca78410403dd64ac0ee0e3cc8646b38335271bfd Mon Sep 17 00:00:00 2001 From: Mika Westerberg Date: Thu, 22 Aug 2019 11:55:53 +0300 Subject: PCI: Get rid of dev->has_secondary_link flag In some systems, the Device/Port Type in the PCI Express Capabilities register incorrectly identifies upstream ports as downstream ports. d0751b98dfa3 ("PCI: Add dev->has_secondary_link to track downstream PCIe links") addressed this by adding pci_dev.has_secondary_link, which is set for downstream ports. But this is confusing because pci_pcie_type() sometimes gives the wrong answer, and it's not obvious that we should use pci_dev.has_secondary_link instead. Reduce the confusion by correcting the type of the port itself so that pci_pcie_type() returns the actual type regardless of what the Device/Port Type register claims it is. Update the users to call pci_pcie_type() and pcie_downstream_port() accordingly, and remove pci_dev.has_secondary_link completely. Link: https://lore.kernel.org/linux-pci/20190703133953.GK128603@google.com/ Suggested-by: Bjorn Helgaas Link: https://lore.kernel.org/r/20190822085553.62697-2-mika.westerberg@linux.intel.com Signed-off-by: Mika Westerberg Signed-off-by: Bjorn Helgaas Reviewed-by: Andy Shevchenko --- drivers/pci/pci.c | 2 +- drivers/pci/pcie/aspm.c | 8 ++++---- drivers/pci/pcie/err.c | 2 +- drivers/pci/probe.c | 48 ++++++++++++++++++++++++++++-------------------- drivers/pci/vc.c | 4 +++- 5 files changed, 37 insertions(+), 27 deletions(-) (limited to 'drivers/pci') diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 29ed5ec1ac27..97e7f6e0821e 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -3576,7 +3576,7 @@ int pci_enable_atomic_ops_to_root(struct pci_dev *dev, u32 cap_mask) } /* Ensure upstream ports don't block AtomicOps on egress */ - if (!bridge->has_secondary_link) { + if (pci_pcie_type(bridge) == PCI_EXP_TYPE_UPSTREAM) { pcie_capability_read_dword(bridge, PCI_EXP_DEVCTL2, &ctl2); if (ctl2 & PCI_EXP_DEVCTL2_ATOMIC_EGRESS_BLOCK) diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index e44af7f4d37f..dcda96818eb6 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -913,10 +913,10 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev) /* * We allocate pcie_link_state for the component on the upstream - * end of a Link, so there's nothing to do unless this device has a - * Link on its secondary side. + * end of a Link, so there's nothing to do unless this device is + * downstream port. */ - if (!pdev->has_secondary_link) + if (!pcie_downstream_port(pdev)) return; /* VIA has a strange chipset, root port is under a bridge */ @@ -1070,7 +1070,7 @@ static int __pci_disable_link_state(struct pci_dev *pdev, int state, bool sem) if (!pci_is_pcie(pdev)) return 0; - if (pdev->has_secondary_link) + if (pcie_downstream_port(pdev)) parent = pdev; if (!parent || !parent->link_state) return -EINVAL; diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c index 773197a12568..b0e6048a9208 100644 --- a/drivers/pci/pcie/err.c +++ b/drivers/pci/pcie/err.c @@ -166,7 +166,7 @@ static pci_ers_result_t reset_link(struct pci_dev *dev, u32 service) driver = pcie_port_find_service(dev, service); if (driver && driver->reset_link) { status = driver->reset_link(dev); - } else if (dev->has_secondary_link) { + } else if (pcie_downstream_port(dev)) { status = default_reset_link(dev); } else { pci_printk(KERN_DEBUG, dev, "no link-reset support at upstream device %s\n", diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index cdf34a3c531a..3bfa57d58402 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -1431,26 +1431,38 @@ void set_pcie_port_type(struct pci_dev *pdev) pci_read_config_word(pdev, pos + PCI_EXP_DEVCAP, ®16); pdev->pcie_mpss = reg16 & PCI_EXP_DEVCAP_PAYLOAD; + parent = pci_upstream_bridge(pdev); + if (!parent) + return; + /* - * A Root Port or a PCI-to-PCIe bridge is always the upstream end - * of a Link. No PCIe component has two Links. Two Links are - * connected by a Switch that has a Port on each Link and internal - * logic to connect the two Ports. + * Some systems do not identify their upstream/downstream ports + * correctly so detect impossible configurations here and correct + * the port type accordingly. */ type = pci_pcie_type(pdev); - if (type == PCI_EXP_TYPE_ROOT_PORT || - type == PCI_EXP_TYPE_PCIE_BRIDGE) - pdev->has_secondary_link = 1; - else if (type == PCI_EXP_TYPE_UPSTREAM || - type == PCI_EXP_TYPE_DOWNSTREAM) { - parent = pci_upstream_bridge(pdev); - + if (type == PCI_EXP_TYPE_DOWNSTREAM) { /* - * Usually there's an upstream device (Root Port or Switch - * Downstream Port), but we can't assume one exists. + * If pdev claims to be downstream port but the parent + * device is also downstream port assume pdev is actually + * upstream port. */ - if (parent && !parent->has_secondary_link) - pdev->has_secondary_link = 1; + if (pcie_downstream_port(parent)) { + pci_info(pdev, "claims to be downstream port but is acting as upstream port, correcting type\n"); + pdev->pcie_flags_reg &= ~PCI_EXP_FLAGS_TYPE; + pdev->pcie_flags_reg |= PCI_EXP_TYPE_UPSTREAM; + } + } else if (type == PCI_EXP_TYPE_UPSTREAM) { + /* + * If pdev claims to be upstream port but the parent + * device is also upstream port assume pdev is actually + * downstream port. + */ + if (pci_pcie_type(parent) == PCI_EXP_TYPE_UPSTREAM) { + pci_info(pdev, "claims to be upstream port but is acting as downstream port, correcting type\n"); + pdev->pcie_flags_reg &= ~PCI_EXP_FLAGS_TYPE; + pdev->pcie_flags_reg |= PCI_EXP_TYPE_DOWNSTREAM; + } } } @@ -2488,12 +2500,8 @@ static int only_one_child(struct pci_bus *bus) * A PCIe Downstream Port normally leads to a Link with only Device * 0 on it (PCIe spec r3.1, sec 7.3.1). As an optimization, scan * only for Device 0 in that situation. - * - * Checking has_secondary_link is a hack to identify Downstream - * Ports because sometimes Switches are configured such that the - * PCIe Port Type labels are backwards. */ - if (bridge && pci_is_pcie(bridge) && bridge->has_secondary_link) + if (bridge && pci_is_pcie(bridge) && pcie_downstream_port(bridge)) return 1; return 0; diff --git a/drivers/pci/vc.c b/drivers/pci/vc.c index 5acd9c02683a..9ae9fb9339e8 100644 --- a/drivers/pci/vc.c +++ b/drivers/pci/vc.c @@ -13,6 +13,8 @@ #include #include +#include "pci.h" + /** * pci_vc_save_restore_dwords - Save or restore a series of dwords * @dev: device @@ -105,7 +107,7 @@ static void pci_vc_enable(struct pci_dev *dev, int pos, int res) struct pci_dev *link = NULL; /* Enable VCs from the downstream device */ - if (!dev->has_secondary_link) + if (!pci_is_pcie(dev) || !pcie_downstream_port(dev)) return; ctrl_pos = pos + PCI_VC_RES_CTRL + (res * PCI_CAP_VC_PER_VC_SIZEOF); -- cgit v1.2.3