PCI: Cache ACS capability offset in device
Currently the ACS capability is being looked up at a number of places. Read
and store it once at enumeration so that it can be used by all later. No
functional change intended.
Link: https://lore.kernel.org/r/20200707224604.3737893-2-rajatja@google.com
Signed-off-by: Rajat Jain <rajatja@google.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index eec625f..73a8627 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -831,7 +831,7 @@ static void pci_disable_acs_redir(struct pci_dev *dev)
if (!pci_dev_specific_disable_acs_redir(dev))
return;
- pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ACS);
+ pos = dev->acs_cap;
if (!pos) {
pci_warn(dev, "cannot disable ACS redirect for this hardware as it does not have ACS capabilities\n");
return;
@@ -857,7 +857,7 @@ static void pci_std_enable_acs(struct pci_dev *dev)
u16 cap;
u16 ctrl;
- pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ACS);
+ pos = dev->acs_cap;
if (!pos)
return;
@@ -883,7 +883,7 @@ static void pci_std_enable_acs(struct pci_dev *dev)
* pci_enable_acs - enable ACS if hardware support it
* @dev: the PCI device
*/
-void pci_enable_acs(struct pci_dev *dev)
+static void pci_enable_acs(struct pci_dev *dev)
{
if (!pci_acs_enable)
goto disable_acs_redir;
@@ -3362,7 +3362,7 @@ static bool pci_acs_flags_enabled(struct pci_dev *pdev, u16 acs_flags)
int pos;
u16 cap, ctrl;
- pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_ACS);
+ pos = pdev->acs_cap;
if (!pos)
return false;
@@ -3488,6 +3488,18 @@ bool pci_acs_path_enabled(struct pci_dev *start,
}
/**
+ * pci_acs_init - Initialize ACS if hardware supports it
+ * @dev: the PCI device
+ */
+void pci_acs_init(struct pci_dev *dev)
+{
+ dev->acs_cap = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ACS);
+
+ if (dev->acs_cap)
+ pci_enable_acs(dev);
+}
+
+/**
* pci_rebar_find_pos - find position of resize ctrl reg for BAR
* @pdev: PCI device
* @bar: BAR to find