[Qemu-devel] [PATCH 01/18] pci: allow to loop over capabilities

[Gerd Hoffmann <kraxel@redhat.com>]

Add a parameter to pci_find_capability, to specify the start point.
This allows to find multiple capabilities of the same type, by calling
pci_find_capability again with the offset of the last capability found.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 src/fw/pciinit.c |  4 ++--
 src/hw/pci.c     | 11 ++++++++---
 src/hw/pci.h     |  2 +-
 3 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c
index ac39d23..45870f2 100644
--- a/src/fw/pciinit.c
+++ b/src/fw/pciinit.c
@@ -642,7 +642,7 @@ pci_region_create_entry(struct pci_bus *bus, struct pci_device *dev,
 
 static int pci_bus_hotplug_support(struct pci_bus *bus)
 {
-    u8 pcie_cap = pci_find_capability(bus->bus_dev, PCI_CAP_ID_EXP);
+    u8 pcie_cap = pci_find_capability(bus->bus_dev, PCI_CAP_ID_EXP, 0);
     u8 shpc_cap;
 
     if (pcie_cap) {
@@ -666,7 +666,7 @@ static int pci_bus_hotplug_support(struct pci_bus *bus)
         return downstream_port && slot_implemented;
     }
 
-    shpc_cap = pci_find_capability(bus->bus_dev, PCI_CAP_ID_SHPC);
+    shpc_cap = pci_find_capability(bus->bus_dev, PCI_CAP_ID_SHPC, 0);
     return !!shpc_cap;
 }
 
diff --git a/src/hw/pci.c b/src/hw/pci.c
index 0379b55..a241d06 100644
--- a/src/hw/pci.c
+++ b/src/hw/pci.c
@@ -221,16 +221,21 @@ pci_find_init_device(const struct pci_device_id *ids, void *arg)
     return NULL;
 }
 
-u8 pci_find_capability(struct pci_device *pci, u8 cap_id)
+u8 pci_find_capability(struct pci_device *pci, u8 cap_id, u8 cap)
 {
     int i;
-    u8 cap;
     u16 status = pci_config_readw(pci->bdf, PCI_STATUS);
 
     if (!(status & PCI_STATUS_CAP_LIST))
         return 0;
 
-    cap = pci_config_readb(pci->bdf, PCI_CAPABILITY_LIST);
+    if (cap == 0) {
+        /* find first */
+        cap = pci_config_readb(pci->bdf, PCI_CAPABILITY_LIST);
+    } else {
+        /* find next */
+        cap = pci_config_readb(pci->bdf, cap + PCI_CAP_LIST_NEXT);
+    }
     for (i = 0; cap && i <= 0xff; i++) {
         if (pci_config_readb(pci->bdf, cap + PCI_CAP_LIST_ID) == cap_id)
             return cap;
diff --git a/src/hw/pci.h b/src/hw/pci.h
index 0aaa84c..fc5e7b9 100644
--- a/src/hw/pci.h
+++ b/src/hw/pci.h
@@ -123,7 +123,7 @@ int pci_init_device(const struct pci_device_id *ids
                     , struct pci_device *pci, void *arg);
 struct pci_device *pci_find_init_device(const struct pci_device_id *ids
                                         , void *arg);
-u8 pci_find_capability(struct pci_device *pci, u8 cap_id);
+u8 pci_find_capability(struct pci_device *pci, u8 cap_id, u8 cap);
 int pci_bridge_has_region(struct pci_device *pci,
                           enum pci_region_type region_type);
 void pci_reboot(void);
-- 
1.8.3.1