[PATCH i-g-t v3 1/2] lib/igt_pm: Introduce helper to check for PM capability

[Jakub Kolakowski <jakub1.kolakowski@intel.com>]

Introduce igt_has_pci_pm_capability(), a helper function to check
whether a PCI device supports the PCI Power Management (PM) capability.
With this helper one can make sure the capability is present on device
under test before proceeding with any actions related to PM.

Cc: Adam Miszczak <adam.miszczak@linux.intel.com>
Cc: Lukasz Laguna <lukasz.laguna@intel.com>
Cc: Marcin Bernatowicz <marcin.bernatowicz@linux.intel.com>
Signed-off-by: Jakub Kolakowski <jakub1.kolakowski@intel.com>
---
 lib/igt_pm.c | 19 ++++++++++++++++++-
 lib/igt_pm.h |  1 +
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/lib/igt_pm.c b/lib/igt_pm.c
index 1a5d9c42b..7f9cbd69a 100644
--- a/lib/igt_pm.c
+++ b/lib/igt_pm.c
@@ -40,10 +40,11 @@
 #include <dirent.h>
 
 #include "drmtest.h"
+#include "igt_aux.h"
 #include "igt_device_scan.h"
 #include "igt_kms.h"
+#include "igt_pci.h"
 #include "igt_pm.h"
-#include "igt_aux.h"
 #include "igt_sysfs.h"
 
 /**
@@ -81,6 +82,7 @@ enum {
 #define MAX_POLICY_STRLEN	strlen(MAX_PERFORMANCE_STR)
 /* Root Port bus can have max 32 dev and each dev can have max 8 func */
 #define MAX_PCI_DEVICES		256
+#define PCI_PM_CAP_ID 0x01
 int8_t *__sata_pm_policies;
 int __scsi_host_cnt;
 
@@ -1470,3 +1472,18 @@ void igt_pm_ignore_slpc_efficient_freq(int i915, int gtfd, bool val)
 	igt_require(igt_sysfs_has_attr(gtfd, "slpc_ignore_eff_freq"));
 	igt_sysfs_set_u32(gtfd, "slpc_ignore_eff_freq", val);
 }
+
+/**
+ * igt_has_pci_pm_capability:
+ * @pci_dev: PCI device struct
+ *
+ * Returns: true if the device has PCI Power Management capability, false otherwise.
+ */
+bool igt_has_pci_pm_capability(struct pci_device *pci_dev)
+{
+	int offset;
+
+	offset = find_pci_cap_offset(pci_dev, PCI_PM_CAP_ID);
+
+	return (offset > 0);
+}
diff --git a/lib/igt_pm.h b/lib/igt_pm.h
index 6b428f53e..c73972f2a 100644
--- a/lib/igt_pm.h
+++ b/lib/igt_pm.h
@@ -97,5 +97,6 @@ uint64_t igt_pm_get_runtime_suspended_time(struct pci_device *pci_dev);
 uint64_t igt_pm_get_runtime_active_time(struct pci_device *pci_dev);
 int igt_pm_get_runtime_usage(struct pci_device *pci_dev);
 void igt_pm_ignore_slpc_efficient_freq(int i915, int gtfd, bool val);
+bool igt_has_pci_pm_capability(struct pci_device *pci_dev);
 
 #endif /* IGT_PM_H */
-- 
2.34.1