[PATCH v2 i-g-t 1/5] lib/xe_sriov_debugfs: Add helper for opening attributes

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

From: Lukasz Laguna <lukasz.laguna@intel.com>

Helper allows to open SR-IOV debugfs attributes corresponding to
specified PF device, VF number and GT number.

v2: Remove unnecessary include (Kamil)

Signed-off-by: Lukasz Laguna <lukasz.laguna@intel.com>
Signed-off-by: Marcin Bernatowicz <marcin.bernatowicz@linux.intel.com>
Reviewed-by: Adam Miszczak <adam.miszczak@linux.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: Michał Wajdeczko <michal.wajdeczko@intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Narasimha C V <narasimha.c.v@intel.com>
Cc: Piotr Piórkowski <piotr.piorkowski@intel.com>
Cc: Satyanarayana K V P <satyanarayana.k.v.p@intel.com>
Cc: Tomasz Lis <tomasz.lis@intel.com>
---
 lib/meson.build           |  1 +
 lib/xe/xe_sriov_debugfs.c | 69 +++++++++++++++++++++++++++++++++++++++
 lib/xe/xe_sriov_debugfs.h | 12 +++++++
 3 files changed, 82 insertions(+)
 create mode 100644 lib/xe/xe_sriov_debugfs.c
 create mode 100644 lib/xe/xe_sriov_debugfs.h

diff --git a/lib/meson.build b/lib/meson.build
index c3556a921..3d5d68b75 100644
--- a/lib/meson.build
+++ b/lib/meson.build
@@ -116,6 +116,7 @@ lib_sources = [
 	'xe/xe_mmio.c',
 	'xe/xe_query.c',
 	'xe/xe_spin.c',
+	'xe/xe_sriov_debugfs.c',
 	'xe/xe_util.c',
 ]
 
diff --git a/lib/xe/xe_sriov_debugfs.c b/lib/xe/xe_sriov_debugfs.c
new file mode 100644
index 000000000..dc6ef9da3
--- /dev/null
+++ b/lib/xe/xe_sriov_debugfs.c
@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright(c) 2024 Intel Corporation. All rights reserved.
+ */
+
+#include <dirent.h>
+#include <fcntl.h>
+
+#include "drmtest.h"
+#include "igt_debugfs.h"
+#include "igt_sriov_device.h"
+#include "xe/xe_sriov_debugfs.h"
+#include "xe/xe_query.h"
+
+#define SRIOV_DEBUGFS_PATH_MAX 96
+
+static char *xe_sriov_pf_debugfs_path(int pf, unsigned int vf_num, unsigned int gt_num, char *path,
+				      int pathlen)
+{
+	char sriov_path[SRIOV_DEBUGFS_PATH_MAX];
+
+	if (!igt_debugfs_path(pf, path, pathlen))
+		return NULL;
+
+	if (vf_num)
+		snprintf(sriov_path, SRIOV_DEBUGFS_PATH_MAX, "/gt%u/vf%u/", gt_num, vf_num);
+	else
+		snprintf(sriov_path, SRIOV_DEBUGFS_PATH_MAX, "/gt%u/pf/", gt_num);
+
+	strncat(path, sriov_path, pathlen - strlen(path));
+
+	if (access(path, F_OK))
+		return NULL;
+
+	return path;
+}
+
+/**
+ * xe_sriov_pf_debugfs_attr_open:
+ * @pf: PF device file descriptor
+ * @vf_num: VF number (1-based) or 0 for PF
+ * @gt_num: GT number
+ * @attr: debugfs attribute name
+ * @mode: mode bits as used by open()
+ *
+ * Opens SR-IOV debugfs attribute @attr for given PF device @pf, VF number @vf_num on GT @gt_num.
+ *
+ * Returns:
+ * File descriptor or -1 on failure.
+ */
+int xe_sriov_pf_debugfs_attr_open(int pf, unsigned int vf_num, unsigned int gt_num,
+				  const char *attr, int mode)
+{
+	char path[PATH_MAX];
+	int debugfs;
+
+	igt_assert(igt_sriov_is_pf(pf) && is_xe_device(pf));
+	igt_assert(gt_num < xe_number_gt(pf));
+
+	if (!xe_sriov_pf_debugfs_path(pf, vf_num, gt_num, path, sizeof(path)))
+		return -1;
+
+	strncat(path, attr, sizeof(path) - strlen(path));
+
+	debugfs = open(path, mode);
+	igt_debug_on(debugfs < 0);
+
+	return debugfs;
+}
diff --git a/lib/xe/xe_sriov_debugfs.h b/lib/xe/xe_sriov_debugfs.h
new file mode 100644
index 000000000..9f4ba8f43
--- /dev/null
+++ b/lib/xe/xe_sriov_debugfs.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright(c) 2024 Intel Corporation. All rights reserved.
+ */
+
+#ifndef __XE_SRIOV_DEBUGFS_H__
+#define __XE_SRIOV_DEBUGFS_H__
+
+int xe_sriov_pf_debugfs_attr_open(int pf, unsigned int vf_num, unsigned int gt_num,
+				  const char *attr, int mode);
+
+#endif /* __XE_SRIOV_DEBUGFS_H__ */
-- 
2.31.1