[PATCH] PCI: quirks: update cavium ACS quirk implementation

[Vadim Lomovtsev]

This commit makes PIC ACS quirk applicable only to Cavium PCIE devices
and Cavium PCIE Root Ports which has limited PCI capabilities in terms
of no ACS support. Match function checks for ACS support and exact ACS
bits set at the device capabilities.
Also by this commit we get rid off device ID range values checkings.

Signed-off-by: Vadim Lomovtsev <Vadim.Lomovtsev@xxxxxxxxxxxxxxxxxx>
---
 drivers/pci/quirks.c | 30 +++++++++++++++++++++++++-----
 1 file changed, 25 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index a4d3361..11ca951 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -4211,6 +4211,29 @@ static int pci_quirk_amd_sb_acs(struct pci_dev *dev, u16 acs_flags)
 #endif
 }
 
+#define CAVIUM_ACS_FLAGS (PCI_ACS_SV | PCI_ACS_TB | PCI_ACS_RR | \
+			  PCI_ACS_CR | PCI_ACS_UF | PCI_ACS_DT)
+
+static __inline__  bool pci_quirk_cavium_acs_match(struct pci_dev *dev)
+{
+	int pos = 0;
+	u32 caps = 0;
+
+	/* Filter out a few obvious non-matches first */
+	if (!pci_is_pcie(dev) || pci_pcie_type(dev) != PCI_EXP_TYPE_ROOT_PORT)
+		return false;
+
+	/* Get the ACS caps offset */
+	pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ACS);
+	if (pos) {
+		pci_read_config_dword(dev, pos + PCI_ACS_CAP, &caps);
+		/* If we have no such bits set, then we will need a quirk */
+		return ((caps & CAVIUM_ACS_FLAGS) != CAVIUM_ACS_FLAGS);
+	}
+
+	return true;
+}
+
 static int pci_quirk_cavium_acs(struct pci_dev *dev, u16 acs_flags)
 {
 	/*
@@ -4218,13 +4241,10 @@ static int pci_quirk_cavium_acs(struct pci_dev *dev, u16 acs_flags)
 	 * with other functions, allowing masking out these bits as if they
 	 * were unimplemented in the ACS capability.
 	 */
-	acs_flags &= ~(PCI_ACS_SV | PCI_ACS_TB | PCI_ACS_RR |
-		       PCI_ACS_CR | PCI_ACS_UF | PCI_ACS_DT);
-
-	if (!((dev->device >= 0xa000) && (dev->device <= 0xa0ff)))
+	if (!pci_quirk_cavium_acs_match(dev))
 		return -ENOTTY;
 
-	return acs_flags ? 0 : 1;
+	return acs_flags & ~(CAVIUM_ACS_FLAGS) ? 0 : 1;
 }
 
 static int pci_quirk_xgene_acs(struct pci_dev *dev, u16 acs_flags)
-- 
2.9.5