Currently ACS capabiity is being looked up at a number of places. Read and
store it once at bootup so that it can be used by all later.

Signed-off-by: Rajat Jain <raja...@google.com>
---
v3: fix commit log, remove forward declation of static function
v2: Commit log cosmetic changes

 drivers/pci/p2pdma.c |  2 +-
 drivers/pci/pci.c    | 20 ++++++++++++++++----
 drivers/pci/pci.h    |  2 +-
 drivers/pci/probe.c  |  2 +-
 drivers/pci/quirks.c |  8 ++++----
 include/linux/pci.h  |  1 +
 6 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index e8e444eeb1cd2..f29a48f8fa594 100644
--- 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 eec625f0e594e..73a8627822140 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;
 
@@ -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 6d3f758671064..12fb79fbe29d3 100644
--- 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 2f66988cea257..6d87066a5ecc5 100644
--- 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 812bfc32ecb82..b341628e47527 100644
--- 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 34c1c4f45288f..0ca39042507ce 100644
--- 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 */
-- 
2.27.0.212.ge8ba1cc988-goog

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

Reply via email to