1 files changed, 63 insertions, 0 deletions
diff --git a/tools/power/cpupower/utils/helpers/pci.c b/tools/power/cpupower/utils/helpers/pci.c
new file mode 100644
index 000000000..113f3da2a
--- /dev/null
+++ b/tools/power/cpupower/utils/helpers/pci.c
@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: GPL-2.0
+#if defined(__i386__) || defined(__x86_64__)
+
+#include <helpers/helpers.h>
+
+/*
+ * pci_acc_init
+ *
+ * PCI access helper function depending on libpci
+ *
+ * **pacc : if a valid pci_dev is returned
+ *         *pacc must be passed to pci_acc_cleanup to free it
+ *
+ * domain: domain
+ * bus:    bus
+ * slot:   slot
+ * func:   func
+ * vendor: vendor
+ * device: device
+ * Pass -1 for one of the six above to match any
+ *
+ * Returns :
+ * struct pci_dev which can be used with pci_{read,write}_* functions
+ *                to access the PCI config space of matching pci devices
+ */
+struct pci_dev *pci_acc_init(struct pci_access **pacc, int domain, int bus,
+			     int slot, int func, int vendor, int dev)
+{
+	struct pci_filter filter_nb_link;
+	struct pci_dev *device;
+
+	*pacc = pci_alloc();
+	if (*pacc == NULL)
+		return NULL;
+
+	pci_filter_init(*pacc, &filter_nb_link);
+	filter_nb_link.domain	= domain;
+	filter_nb_link.bus	= bus;
+	filter_nb_link.slot	= slot;
+	filter_nb_link.func	= func;
+	filter_nb_link.vendor	= vendor;
+	filter_nb_link.device	= dev;
+
+	pci_init(*pacc);
+	pci_scan_bus(*pacc);
+
+	for (device = (*pacc)->devices; device; device = device->next) {
+		if (pci_filter_match(&filter_nb_link, device))
+			return device;
+	}
+	pci_cleanup(*pacc);
+	return NULL;
+}
+
+/* Typically one wants to get a specific slot(device)/func of the root domain
+   and bus */
+struct pci_dev *pci_slot_func_init(struct pci_access **pacc, int slot,
+				       int func)
+{
+	return pci_acc_init(pacc, 0, 0, slot, func, -1, -1);
+}
+
+#endif /* defined(__i386__) || defined(__x86_64__) */