[Xen-devel] [PATCH RFC V1 07/11] host-pci-device: Add host_pci_find_ext_cap_offset

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
---
 hw/host-pci-device.c |   31 +++++++++++++++++++++++++++++++
 hw/host-pci-device.h |    2 ++
 2 files changed, 33 insertions(+), 0 deletions(-)

diff --git a/hw/host-pci-device.c b/hw/host-pci-device.c
index b3f2899..2a889d5 100644
--- a/hw/host-pci-device.c
+++ b/hw/host-pci-device.c
@@ -162,6 +162,37 @@ int host_pci_write_block(HostPCIDevice *d, int pos, 
uint8_t *buf, int len)
   return host_pci_config_write(d, pos, buf, len);
 }
 
+uint32_t host_pci_find_ext_cap_offset(HostPCIDevice *d, uint32_t cap)
+{
+    uint32_t header = 0;
+    int max_cap = 480;
+    int pos = 0x100;
+
+    do {
+        header = host_pci_read_long(d, pos);
+        /*
+         * If we have no capabilities, this is indicated by cap ID,
+         * cap version and next pointer all being 0.
+         */
+        if (header == 0) {
+            break;
+        }
+
+        if (PCI_EXT_CAP_ID(header) == cap) {
+            return pos;
+        }
+
+        pos = PCI_EXT_CAP_NEXT(header);
+        if (pos < 0x100) {
+            break;
+        }
+
+        max_cap--;
+    } while (max_cap > 0);
+
+    return 0;
+}
+
 HostPCIDevice *host_pci_device_get(uint8_t bus, uint8_t dev, uint8_t func)
 {
     HostPCIDevice *d = NULL;
diff --git a/hw/host-pci-device.h b/hw/host-pci-device.h
index 0137507..2734eb3 100644
--- a/hw/host-pci-device.h
+++ b/hw/host-pci-device.h
@@ -33,4 +33,6 @@ int host_pci_write_word(HostPCIDevice *d, int pos, uint16_t 
data);
 int host_pci_write_long(HostPCIDevice *d, int pos, uint32_t data);
 int host_pci_write_block(HostPCIDevice *d, int pos, uint8_t *buf, int len);
 
+uint32_t host_pci_find_ext_cap_offset(HostPCIDevice *s, uint32_t cap);
+
 #endif /* !HW_HOST_PCI_DEVICE */
-- 
Anthony PERARD


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