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

[Jakub Kolakowski]

Add power management capability checking helper. With this helper one
can make sure the capability is present on device under test before
proceeding with any actions related to PM. This is mainly aimed to check
for availability of D-states but overall it checks for the PCI
capability in general.

Cc: Adam Miszczak <adam.miszczak at linux.intel.com>
Cc: Lukasz Laguna <lukasz.laguna at intel.com>
Cc: Marcin Bernatowicz <marcin.bernatowicz at linux.intel.com>
Signed-off-by: Jakub Kolakowski <jakub1.kolakowski at intel.com>
---
 lib/igt_pm.c | 20 ++++++++++++++++++++
 lib/igt_pm.h |  1 +
 2 files changed, 21 insertions(+)

diff --git a/lib/igt_pm.c b/lib/igt_pm.c
index 1a5d9c42b..21e3137ab 100644
--- a/lib/igt_pm.c
+++ b/lib/igt_pm.c
@@ -45,6 +45,7 @@
 #include "igt_pm.h"
 #include "igt_aux.h"
 #include "igt_sysfs.h"
+#include "igt_pci.h"
 
 /**
  * SECTION:igt_pm
@@ -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 +1472,21 @@ 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_is_pm_supported:
+ * @dev: pci device
+ *
+ * Returns: True if power management capability is present, otherwise false
+ */
+bool igt_is_pm_supported(struct pci_device *pci_dev)
+{
+	int offset;
+
+	offset = find_pci_cap_offset(pci_dev, PCI_PM_CAP_ID);
+	if (offset > 0)
+		return true;
+
+	return false;
+}
\ No newline at end of file
diff --git a/lib/igt_pm.h b/lib/igt_pm.h
index 6b428f53e..befb61f3c 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_is_pm_supported(struct pci_device *pci_dev);
 
 #endif /* IGT_PM_H */
-- 
2.34.1