PCI: don't enable too many HT MSI mappings

Prakash reported that his c51-mcp51 ondie sound card doesn't work with
MSI.  But if he hacks out the HT-MSI quirk, MSI works fine.

So this patch reworks the nv_msi_ht_cap_quirk().  It will now only
enable ht_msi on own its root device, avoiding enabling it on devices
following that root dev.

Reported-by: Prakash Punnoor <prakash@punnoor.de>
Tested-by: Prakash Punnoor <prakash@punnoor.de>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Jesse Barnes <jbarnes@hobbes.lan>

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index a21e1c2..a852329 100644 (file)
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -2050,10 +2050,100 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_NVIDIA,
                        PCI_DEVICE_ID_NVIDIA_NVENET_15,
                        nvenet_msi_disable);
 
-static void __devinit nv_msi_ht_cap_quirk(struct pci_dev *dev)
+static void __devinit nv_ht_enable_msi_mapping(struct pci_dev *dev)
 {
        struct pci_dev *host_bridge;
+       int pos;
+       int i, dev_no;
+       int found = 0;
+
+       dev_no = dev->devfn >> 3;
+       for (i = dev_no; i >= 0; i--) {
+               host_bridge = pci_get_slot(dev->bus, PCI_DEVFN(i, 0));
+               if (!host_bridge)
+                       continue;
+
+               pos = pci_find_ht_capability(host_bridge, HT_CAPTYPE_SLAVE);
+               if (pos != 0) {
+                       found = 1;
+                       break;
+               }
+               pci_dev_put(host_bridge);
+       }
+
+       if (!found)
+               return;
+
+       /* root did that ! */
+       if (msi_ht_cap_enabled(host_bridge))
+               goto out;
+
+       ht_enable_msi_mapping(dev);
+
+out:
+       pci_dev_put(host_bridge);
+}
+
+static void __devinit ht_disable_msi_mapping(struct pci_dev *dev)
+{
+       int pos, ttl = 48;
+
+       pos = pci_find_ht_capability(dev, HT_CAPTYPE_MSI_MAPPING);
+       while (pos && ttl--) {
+               u8 flags;
+
+               if (pci_read_config_byte(dev, pos + HT_MSI_FLAGS,
+                                        &flags) == 0) {
+                       dev_info(&dev->dev, "Enabling HT MSI Mapping\n");
+
+                       pci_write_config_byte(dev, pos + HT_MSI_FLAGS,
+                                             flags & ~HT_MSI_FLAGS_ENABLE);
+               }
+               pos = pci_find_next_ht_capability(dev, pos,
+                                                 HT_CAPTYPE_MSI_MAPPING);
+       }
+}
+
+static int __devinit ht_check_msi_mapping(struct pci_dev *dev)
+{
        int pos, ttl = 48;
+       int found = 0;
+
+       /* check if there is HT MSI cap or enabled on this device */
+       pos = pci_find_ht_capability(dev, HT_CAPTYPE_MSI_MAPPING);
+       while (pos && ttl--) {
+               u8 flags;
+
+               if (found < 1)
+                       found = 1;
+               if (pci_read_config_byte(dev, pos + HT_MSI_FLAGS,
+                                        &flags) == 0) {
+                       if (flags & HT_MSI_FLAGS_ENABLE) {
+                               if (found < 2) {
+                                       found = 2;
+                                       break;
+                               }
+                       }
+               }
+               pos = pci_find_next_ht_capability(dev, pos,
+                                                 HT_CAPTYPE_MSI_MAPPING);
+       }
+
+       return found;
+}
+
+static void __devinit nv_msi_ht_cap_quirk(struct pci_dev *dev)
+{
+       struct pci_dev *host_bridge;
+       int pos;
+       int found;
+
+       /* check if there is HT MSI cap or enabled on this device */
+       found = ht_check_msi_mapping(dev);
+
+       /* no HT MSI CAP */
+       if (found == 0)
+               return;
 
        /*
         * HT MSI mapping should be disabled on devices that are below
@@ -2069,24 +2159,19 @@ static void __devinit nv_msi_ht_cap_quirk(struct pci_dev *dev)
        pos = pci_find_ht_capability(host_bridge, HT_CAPTYPE_SLAVE);
        if (pos != 0) {
                /* Host bridge is to HT */
-               ht_enable_msi_mapping(dev);
+               if (found == 1) {
+                       /* it is not enabled, try to enable it */
+                       nv_ht_enable_msi_mapping(dev);
+               }
                return;
        }
 
-       /* Host bridge is not to HT, disable HT MSI mapping on this device */
-       pos = pci_find_ht_capability(dev, HT_CAPTYPE_MSI_MAPPING);
-       while (pos && ttl--) {
-               u8 flags;
+       /* HT MSI is not enabled */
+       if (found == 1)
+               return;
 
-               if (pci_read_config_byte(dev, pos + HT_MSI_FLAGS,
-                                        &flags) == 0) {
-                       dev_info(&dev->dev, "Disabling HT MSI mapping");
-                       pci_write_config_byte(dev, pos + HT_MSI_FLAGS,
-                                             flags & ~HT_MSI_FLAGS_ENABLE);
-               }
-               pos = pci_find_next_ht_capability(dev, pos,
-                                                 HT_CAPTYPE_MSI_MAPPING);
-       }
+       /* Host bridge is not to HT, disable HT MSI mapping on this device */
+       ht_disable_msi_mapping(dev);
 }
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID, nv_msi_ht_cap_quirk);
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AL, PCI_ANY_ID, nv_msi_ht_cap_quirk);