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/p2pdma.c b/drivers/pci/p2pdma.c
index e8e444eeb1cd263e2ab4705b31632de6042be8d4..f29a48f8fa594d4ddd4be8350a6e2ef602dfd6d6 100644 (file)
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -253,7 +253,7 @@ static int pci_bridge_has_acs_redir(struct pci_dev *pdev)
        int pos;
        u16 ctrl;
 
-       pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_ACS);
+       pos = pdev->acs_cap;
        if (!pos)
                return 0;
 

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index eec625f0e594e86a6849ac8ce5c624a084b16417..73a86278221401794f1dec1deb99cef106e785dd 100644 (file)
--- 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;
 
@@ -3487,6 +3487,18 @@ bool pci_acs_path_enabled(struct pci_dev *start,
        return true;
 }
 
+/**
+ * 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

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 6d3f758671064ff5fd2a35af093bce6a69174b45..12fb79fbe29d3cd7ad660de9273a318ba22c7be6 100644 (file)
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -532,7 +532,7 @@ static inline resource_size_t pci_resource_alignment(struct pci_dev *dev,
        return resource_alignment(res);
 }
 
-void pci_enable_acs(struct pci_dev *dev);
+void pci_acs_init(struct pci_dev *dev);
 #ifdef CONFIG_PCI_QUIRKS
 int pci_dev_specific_acs_enabled(struct pci_dev *dev, u16 acs_flags);
 int pci_dev_specific_enable_acs(struct pci_dev *dev);

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 2f66988cea25756e7c93caa7b8da022cb98c0396..6d87066a5ecc5260422daeebb1a2d985614eb760 100644 (file)
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2390,7 +2390,7 @@ static void pci_init_capabilities(struct pci_dev *dev)
        pci_ats_init(dev);              /* Address Translation Services */
        pci_pri_init(dev);              /* Page Request Interface */
        pci_pasid_init(dev);            /* Process Address Space ID */
-       pci_enable_acs(dev);            /* Enable ACS P2P upstream forwarding */
+       pci_acs_init(dev);              /* Access Control Services */
        pci_ptm_init(dev);              /* Precision Time Measurement */
        pci_aer_init(dev);              /* Advanced Error Reporting */
        pci_dpc_init(dev);              /* Downstream Port Containment */

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 812bfc32ecb82bcc149a51e338bfc853a16c52f8..b341628e47527fdfdf54295bbbecd417f7d16c69 100644 (file)
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -4653,7 +4653,7 @@ static int pci_quirk_intel_spt_pch_acs(struct pci_dev *dev, u16 acs_flags)
        if (!pci_quirk_intel_spt_pch_acs_match(dev))
                return -ENOTTY;
 
-       pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ACS);
+       pos = dev->acs_cap;
        if (!pos)
                return -ENOTTY;
 
@@ -4961,7 +4961,7 @@ static int pci_quirk_enable_intel_spt_pch_acs(struct pci_dev *dev)
        if (!pci_quirk_intel_spt_pch_acs_match(dev))
                return -ENOTTY;
 
-       pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ACS);
+       pos = dev->acs_cap;
        if (!pos)
                return -ENOTTY;
 
@@ -4988,7 +4988,7 @@ static int pci_quirk_disable_intel_spt_pch_acs_redir(struct pci_dev *dev)
        if (!pci_quirk_intel_spt_pch_acs_match(dev))
                return -ENOTTY;
 
-       pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ACS);
+       pos = dev->acs_cap;
        if (!pos)
                return -ENOTTY;
 
@@ -5355,7 +5355,7 @@ int pci_idt_bus_quirk(struct pci_bus *bus, int devfn, u32 *l, int timeout)
        bool found;
        struct pci_dev *bridge = bus->self;
 
-       pos = pci_find_ext_capability(bridge, PCI_EXT_CAP_ID_ACS);
+       pos = bridge->acs_cap;
 
        /* Disable ACS SV before initial config reads */
        if (pos) {

diff --git a/include/linux/pci.h b/include/linux/pci.h
index c79d83304e5293330f38ebb73a630daa499c9a6c..a26be5332bba63c50ed04f26aabe40acc48778ad 100644 (file)
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -486,6 +486,7 @@ struct pci_dev {
 #ifdef CONFIG_PCI_P2PDMA
        struct pci_p2pdma *p2pdma;
 #endif
+       u16             acs_cap;        /* ACS Capability offset */
        phys_addr_t     rom;            /* Physical address if not from BAR */
        size_t          romlen;         /* Length if not from BAR */
        char            *driver_override; /* Driver name to force a match */