[PATCH v2 i-g-t 1/4] lib/igt_sriov_device: Add helper to get VF PCI slot address

[Marcin Bernatowicz <marcin.bernatowicz@linux.intel.com>]

Add igt_sriov_get_vf_pci_slot_alloc() to resolve the PCI slot address
of a VF by following the device/virtfnX symlink in the PF sysfs
directory, returning a newly allocated string or NULL on failure.

Signed-off-by: Marcin Bernatowicz <marcin.bernatowicz@linux.intel.com>
Reviewed-by: Lukasz Laguna <lukasz.laguna@intel.com>
Cc: Adam Miszczak <adam.miszczak@linux.intel.com>
Cc: Jakub Kolakowski <jakub1.kolakowski@intel.com>
Cc: Kamil Konieczny <kamil.konieczny@linux.intel.com>
Cc: Lukasz Laguna <lukasz.laguna@intel.com>
---
 lib/igt_sriov_device.c | 25 +++++++++++++++++++++++++
 lib/igt_sriov_device.h |  1 +
 2 files changed, 26 insertions(+)

diff --git a/lib/igt_sriov_device.c b/lib/igt_sriov_device.c
index 788ffbfa1..1f4c3ac04 100644
--- a/lib/igt_sriov_device.c
+++ b/lib/igt_sriov_device.c
@@ -354,6 +354,31 @@ static char *__igt_sriov_get_vf_pci_slot_alloc(int pf_sysfs, unsigned int vf_num
 	return pci_slot_addr ? strdup(pci_slot_addr) : NULL;
 }
 
+/**
+ * igt_sriov_get_vf_pci_slot_alloc:
+ * @pf: PF device file descriptor
+ * @vf_num: VF number (1-based); 0 means PF
+ *
+ * Resolves the symlink under the PF sysfs directory (device/virtfnX) to obtain
+ * the PCI slot address of the VF (or PF if @vf_num is 0).
+ *
+ * Returns: newly allocated PCI slot address string (e.g. "0000:3b:00.4"),
+ * or NULL on failure. Caller must free().
+ */
+char *igt_sriov_get_vf_pci_slot_alloc(int pf, unsigned int vf_num)
+{
+	char *pci_slot;
+	int sysfs;
+
+	sysfs = igt_sysfs_open(pf);
+	igt_assert_fd(sysfs);
+
+	pci_slot = __igt_sriov_get_vf_pci_slot_alloc(sysfs, vf_num);
+	close(sysfs);
+
+	return pci_slot;
+}
+
 static bool __igt_sriov_bind_vf_drm_driver(int pf, unsigned int vf_num, bool bind)
 {
 	char *pci_slot;
diff --git a/lib/igt_sriov_device.h b/lib/igt_sriov_device.h
index 84d29b1bb..a417b30d8 100644
--- a/lib/igt_sriov_device.h
+++ b/lib/igt_sriov_device.h
@@ -28,6 +28,7 @@ void igt_sriov_enable_driver_autoprobe(int pf);
 void igt_sriov_disable_driver_autoprobe(int pf);
 int igt_sriov_open_vf_drm_device(int pf, unsigned int vf_num);
 bool igt_sriov_is_vf_drm_driver_probed(int pf, unsigned int vf_num);
+char *igt_sriov_get_vf_pci_slot_alloc(int pf, unsigned int vf_num);
 void igt_sriov_bind_vf_drm_driver(int pf, unsigned int vf_num);
 void igt_sriov_unbind_vf_drm_driver(int pf, unsigned int vf_num);
 int igt_sriov_device_sysfs_open(int pf, unsigned int vf_num);
-- 
2.43.0