[PATCH i-g-t 3/4] lib/igt_kms: add helper to enable/disable force joiner

[Kunal Joshi]

add helpers to check whether force joiner debugfs exists
and to enable/disable force joiner for a specific connector.

v2: Add documentation and rename (Ankit)
    Combine enable/disable and status check (Ankit)
    Don't assert in igt_has_force_joiner_debugfs (Ankit)

Cc: Stanislav Lisovskiy <stanislav.lisovskiy at intel.com>
Cc: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
Cc: Karthik B S <karthik.b.s at intel.com>
Cc: Bhanuprakash Modem <bhanuprakash.modem at intel.com>
Signed-off-by: Kunal Joshi <kunal1.joshi at intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
---
 lib/igt_kms.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
 lib/igt_kms.h |  2 ++
 2 files changed, 53 insertions(+)

diff --git a/lib/igt_kms.c b/lib/igt_kms.c
index 548c9d1f3..c38021dd7 100644
--- a/lib/igt_kms.c
+++ b/lib/igt_kms.c
@@ -6171,6 +6171,57 @@ bool bigjoiner_mode_found(int drm_fd, drmModeConnector *connector,
 	return found;
 }
 
+/**
+ * Checks if the force big joiner debugfs is available
+ * for a specific connector.
+ *
+ * @drmfd: file descriptor of the DRM device.
+ * @output: output to check.
+ * Returns:
+ *  true if the debugfs is available, false otherwise.
+ */
+bool igt_has_force_joiner_debugfs(int drmfd, igt_output_t *output)
+{
+	char buf[512];
+	int debugfs_fd, ret;
+
+	igt_assert_f(output->name, "Connector name cannot be NULL\n");
+	debugfs_fd = igt_debugfs_connector_dir(drmfd, output->name, O_RDONLY);
+	if (debugfs_fd < 0)
+		return false;
+	ret = igt_debugfs_simple_read(debugfs_fd, "i915_bigjoiner_force_enable", buf, sizeof(buf));
+	close(debugfs_fd);
+	return ret >= 0;
+}
+
+/**
+ * Forces the enable/disable state of big joiner for a specific connector.
+ *
+ * @drmfd The file descriptor of the DRM device.
+ * @connector_name The name of the connector.
+ * @enable The desired state of big joiner (true for enable, false for disable).
+ * Returns:
+ *  true if writing the debugfs was successful
+ *  and the state was set as requested, false otherwise.
+ */
+bool igt_force_and_check_bigjoiner_status(int drmfd, char *connector_name, bool enable)
+{
+	int debugfs_fd, ret;
+	char buf[512];
+
+	igt_assert_f(connector_name, "Connector name cannot be NULL\n");
+	debugfs_fd = igt_debugfs_connector_dir(drmfd, connector_name, O_DIRECTORY);
+	igt_assert_f(debugfs_fd >= 0, "Could not open debugfs for connector %s\n", connector_name);
+	ret = igt_sysfs_write(debugfs_fd, "i915_bigjoiner_force_enable", enable ? "1" : "0", 1);
+	igt_assert_f(ret > 0, "Could not write i915_bigjoiner_force_enable for connector %s\n", connector_name);
+	ret = igt_debugfs_simple_read(debugfs_fd, "i915_bigjoiner_force_enable", buf, sizeof(buf));
+	close(debugfs_fd);
+	igt_assert_f(ret > 0, "Could not read i915_bigjoiner_force_enable for connector %s\n", connector_name);
+
+	return enable ? strstr(buf, "Bigjoiner enable: 1") :
+		    strstr(buf, "Bigjoiner enable: 0");
+}
+
 /**
  * igt_check_bigjoiner_support:
  * @display: a pointer to an #igt_display_t structure
diff --git a/lib/igt_kms.h b/lib/igt_kms.h
index 0fa7a2ea1..6d13e5851 100644
--- a/lib/igt_kms.h
+++ b/lib/igt_kms.h
@@ -1214,6 +1214,8 @@ int igt_get_max_dotclock(int fd);
 bool igt_bigjoiner_possible(drmModeModeInfo *mode, int max_dotclock);
 bool bigjoiner_mode_found(int drm_fd, drmModeConnector *connector,
 			  int max_dotclock, drmModeModeInfo *mode);
+bool igt_has_force_joiner_debugfs(int drmfd, igt_output_t *output);
+bool igt_force_and_check_bigjoiner_status(int drmfd, char *connector_name, bool enable);
 bool igt_check_bigjoiner_support(igt_display_t *display);
 bool igt_parse_mode_string(const char *mode_string, drmModeModeInfo *mode);
 bool intel_pipe_output_combo_valid(igt_display_t *display);
-- 
2.25.1