4 files changed, 51 insertions, 0 deletions

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 6fda33de84e8..fc87e14b50de 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -90,3 +90,4 @@ pci_match_one_device(const struct pci_device_id *id, const struct pci_dev *dev)
         return NULL;
 }
 
+struct pci_dev *pci_find_upstream_pcie_bridge(struct pci_dev *pdev);
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 5db6b6690b59..463a5a9d583d 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -837,6 +837,19 @@ static void pci_release_dev(struct device *dev)
         kfree(pci_dev);
 }
 
+static void set_pcie_port_type(struct pci_dev *pdev)
+{
+        int pos;
+        u16 reg16;
+
+        pos = pci_find_capability(pdev, PCI_CAP_ID_EXP);
+        if (!pos)
+                return;
+        pdev->is_pcie = 1;
+        pci_read_config_word(pdev, pos + PCI_EXP_FLAGS, &reg16);
+        pdev->pcie_type = (reg16 & PCI_EXP_FLAGS_TYPE) >> 4;
+}
+
 /**
  * pci_cfg_space_size - get the configuration space size of the PCI device.
  * @dev: PCI device
@@ -951,6 +964,7 @@ pci_scan_device(struct pci_bus *bus, int devfn)
         dev->device = (l >> 16) & 0xffff;
         dev->cfg_size = pci_cfg_space_size(dev);
         dev->error_state = pci_channel_io_normal;
+        set_pcie_port_type(dev);
 
         /* Assume 32-bit PCI; let 64-bit PCI cards (which are far rarer)
            set this higher, assuming the system even supports it.  */
diff --git a/drivers/pci/search.c b/drivers/pci/search.c
index c6e79d01ce3d..b001b5922e33 100644
--- a/drivers/pci/search.c
+++ b/drivers/pci/search.c
@@ -14,6 +14,40 @@
 #include "pci.h"
 
 DECLARE_RWSEM(pci_bus_sem);
+/*
+ * find the upstream PCIE-to-PCI bridge of a PCI device
+ * if the device is PCIE, return NULL
+ * if the device isn't connected to a PCIE bridge (that is its parent is a
+ * legacy PCI bridge and the bridge is directly connected to bus 0), return its
+ * parent
+ */
+struct pci_dev *
+pci_find_upstream_pcie_bridge(struct pci_dev *pdev)
+{
+        struct pci_dev *tmp = NULL;
+
+        if (pdev->is_pcie)
+                return NULL;
+        while (1) {
+                if (!pdev->bus->self)
+                        break;
+                pdev = pdev->bus->self;
+                /* a p2p bridge */
+                if (!pdev->is_pcie) {
+                        tmp = pdev;
+                        continue;
+                }
+                /* PCI device should connect to a PCIE bridge */
+                if (pdev->pcie_type != PCI_EXP_TYPE_PCI_BRIDGE) {
+                        /* Busted hardware? */
+                        WARN_ON_ONCE(1);
+                        return NULL;
+                }
+                return pdev;
+        }
+
+        return tmp;
+}
 
 static struct pci_bus *pci_do_find_bus(struct pci_bus *bus, unsigned char busnr)
 {
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 768b93359f90..5d2281f661f7 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -141,6 +141,7 @@ struct pci_dev {
         unsigned int    class;          /* 3 bytes: (base,sub,prog-if) */
         u8              revision;       /* PCI revision, low byte of class word */
         u8              hdr_type;       /* PCI header type (`multi' flag masked out) */
+        u8              pcie_type;      /* PCI-E device/port type */
         u8              rom_base_reg;   /* which config register controls the ROM */
         u8              pin;            /* which interrupt pin this device uses */
 
@@ -183,6 +184,7 @@ struct pci_dev {
         unsigned int    msi_enabled:1;
         unsigned int    msix_enabled:1;
         unsigned int    is_managed:1;
+        unsigned int    is_pcie:1;
         atomic_t        enable_cnt;     /* pci_enable_device has been called */
 
         u32             saved_config_space[16]; /* config space saved at suspend time */