PCI: Work around Ivytown NTB BAR size issue

Certain NTB devices have a hardware erratum where, regardless of
pre-configured value, reading the BAR size returns 4096.  To work around
this issue, add a PCI quirk to read the appropriate values from an
alternative register in PCI config space and move the resource endpoints
to the appropriate location.

Signed-off-by: Jon Mason <jon.mason@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

1 files changed, 25 insertions, 0 deletions

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 7d68aeebf56b..7f492574dcf4 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -2865,6 +2865,31 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x65f9, quirk_intel_mc_errata);
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x65fa, quirk_intel_mc_errata);
 
 
+/*
+ * Ivytown NTB BAR sizes are misreported by the hardware due to an erratum.  To
+ * work around this, query the size it should be configured to by the device and
+ * modify the resource end to correspond to this new size.
+ */
+static void quirk_intel_ntb(struct pci_dev *dev)
+{
+        int rc;
+        u8 val;
+
+        rc = pci_read_config_byte(dev, 0x00D0, &val);
+        if (rc)
+                return;
+
+        dev->resource[2].end = dev->resource[2].start + ((u64) 1 << val) - 1;
+
+        rc = pci_read_config_byte(dev, 0x00D1, &val);
+        if (rc)
+                return;
+
+        dev->resource[4].end = dev->resource[4].start + ((u64) 1 << val) - 1;
+}
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x0e08, quirk_intel_ntb);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x0e0d, quirk_intel_ntb);
+
 static ktime_t fixup_debug_start(struct pci_dev *dev,
                                  void (*fn)(struct pci_dev *dev))
 {