[PATCH 1/4] Add pci_obff_supported() function.

[Xudong Hao <xudong.hao@xxxxxxxxx>]

Add pci_obff_supported() function and use it by obff relative function.

Signed-off-by: Xudong Hao <xudong.hao@xxxxxxxxx>
---
 drivers/pci/pci.c |   30 ++++++++++++++++++++++++------
 1 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 447e834..a70093b 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -39,6 +39,7 @@ EXPORT_SYMBOL(pci_pci_problems);
 
 unsigned int pci_pm_d3_delay;
 
+static bool pci_obff_supported(struct pci_dev *dev);
 static void pci_pme_list_scan(struct work_struct *work);
 
 static LIST_HEAD(pci_pme_list);
@@ -2071,6 +2072,27 @@ void pci_disable_ido(struct pci_dev *dev, unsigned long type)
 EXPORT_SYMBOL(pci_disable_ido);
 
 /**
+ * pci_obff_supported - check whether a device supports OBFF 
+ * @dev: PCI device
+ *
+ * RETURNS:
+ * True if @dev supports optimized buffer flush/fill, false otherwise.
+ */
+static bool pci_obff_supported(struct pci_dev *dev)
+{
+	int pos;
+	u32 cap;
+
+	pos = pci_pcie_cap(dev);
+	if (!pos)
+		return false;
+
+	pci_read_config_dword(dev, pos + PCI_EXP_DEVCAP2, &cap);
+
+	return cap & PCI_EXP_OBFF_MASK;
+}
+
+/**
  * pci_enable_obff - enable optimized buffer flush/fill
  * @dev: PCI device
  * @type: type of signaling to use
@@ -2096,17 +2118,13 @@ int pci_enable_obff(struct pci_dev *dev, enum pci_obff_signal_type type)
 	u16 ctrl;
 	int ret;
 
-	if (!pci_is_pcie(dev))
+	if (!pci_obff_supported(dev))
 		return -ENOTSUPP;
 
 	pos = pci_pcie_cap(dev);
 	if (!pos)
 		return -ENOTSUPP;
 
-	pci_read_config_dword(dev, pos + PCI_EXP_DEVCAP2, &cap);
-	if (!(cap & PCI_EXP_OBFF_MASK))
-		return -ENOTSUPP; /* no OBFF support at all */
-
 	/* Make sure the topology supports OBFF as well */
 	if (dev->bus) {
 		ret = pci_enable_obff(dev->bus->self, type);
@@ -2149,7 +2167,7 @@ void pci_disable_obff(struct pci_dev *dev)
 	int pos;
 	u16 ctrl;
 
-	if (!pci_is_pcie(dev))
+	if (!pci_obff_supported(dev))
 		return;
 
 	pos = pci_pcie_cap(dev);
-- 
1.5.5

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