lib/igt_amd: add helpers to check PSR capibility

[why]
For AMDGPU devices, the debugfs interface to check sink PSR cap
is a bit different from that of i915, i.e. the interface is located
in the path
<debugfs_root>/dri/0/eDP-X/psr_capability
where 'X' is eDP connector index.

We need such debugfs interface to check if the sink device and the
x86 driver supports PSR or PSR-SU capabilities.

[how]
define and add the helpers to read from connector debugfs interface

For sink device PSR cap check:
- for PSR1 device, the psr version DPCD be 0x1
- for PSR-SU device, the psr version DPCD be either 0x3 or 0x4.

For amdgpu x86 driver PSR support check:
- for PSR1, expect to contain sub-string "yes"
- for PSR-SU, expect to contain sub-string "yes [0x1]"

changes in v2
-------------------
* fix the typo in string comp within the helper to read from
  psr cap debugfs interface

Cc: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Leo Li <sunpeng.li@amd.com>
Cc: Aurabindo Pillai <aurabindo.pillai@amd.com>
Cc: Wayne Lin <wayne.lin@amd.com>

Signed-off-by: David Zhang <dingchen.zhang@amd.com>
Reviewed-by: Aurabindo Pillai <aurabindo.pillai@amd.com>

2 files changed, 101 insertions, 0 deletions

diff --git a/lib/igt_amd.c b/lib/igt_amd.c
index ae94fb99..577a8612 100644
--- a/lib/igt_amd.c
+++ b/lib/igt_amd.c
@@ -1004,3 +1004,96 @@ bool igt_amd_output_has_ilr_setting(int drm_fd, char *connector_name)
 	close(fd);
 	return true;
 }
+
+/**
+ * igt_amd_output_has_psr_cap: check if eDP connector has psr_capability debugfs entry
+ * @drm_fd: DRM file descriptor
+ * @connector_name: The connector's name, on which we're reading the status
+ */
+bool igt_amd_output_has_psr_cap(int drm_fd, char *connector_name)
+{
+	int fd;
+	int res;
+	struct stat stat;
+
+	fd = igt_debugfs_connector_dir(drm_fd, connector_name, O_RDONLY);
+	if (fd < 0) {
+		igt_info("output %s: debugfs not found\n", connector_name);
+		return false;
+	}
+
+	res = fstatat(fd, DEBUGFS_EDP_PSR_CAP, &stat, 0);
+	if (res != 0) {
+		igt_info("output %s: %s debugfs not supported\n", connector_name, DEBUGFS_EDP_PSR_CAP);
+		close(fd);
+		return false;
+	}
+
+	close(fd);
+	return true;
+}
+
+/**
+ * igt_amd_psr_support_sink: check if sink device support PSR
+ * @drm_fd: DRM file descriptor
+ * @connector_name: The connector's name, on which we're reading the status
+ * @mode: expected PSR mode, either PSR1 or PSR2
+ */
+bool igt_amd_psr_support_sink(int drm_fd, char *connector_name, enum psr_mode mode)
+{
+	char buf[PSR_STATUS_MAX_LEN];
+	int ret;
+	int fd;
+
+	fd = igt_debugfs_connector_dir(drm_fd, connector_name, O_RDONLY);
+	if (fd < 0) {
+		igt_info("output %s: debugfs not found\n", connector_name);
+		return false;
+	}
+
+	ret = igt_debugfs_simple_read(fd, DEBUGFS_EDP_PSR_CAP, buf, sizeof(buf));
+	igt_assert_f(ret >= 0, "Reading %s for connector %s failed.\n",
+		     DEBUGFS_EDP_PSR_CAP, connector_name);
+	close(fd);
+
+	if (ret < 1)
+		return false;
+
+	if (mode == PSR_MODE_1)
+		return strstr(buf, "Sink support: yes [0x01]");
+	else
+		return strstr(buf, "Sink support: yes [0x03]") ||
+		       strstr(buf, "Sink support: yes [0x04]");
+}
+
+/**
+ * igt_amd_psr_support_drv: check if AMDGPU kernel driver support PSR
+ * @drm_fd: DRM file descriptor
+ * @connector_name: The connector's name, on which we're reading the status
+ * @mode: expected PSR mode, either PSR1 or PSR2
+ */
+bool igt_amd_psr_support_drv(int drm_fd, char *connector_name, enum psr_mode mode)
+{
+	char buf[PSR_STATUS_MAX_LEN];
+	int ret;
+	int fd;
+
+	fd = igt_debugfs_connector_dir(drm_fd, connector_name, O_RDONLY);
+	if (fd < 0) {
+		igt_info("output %s: debugfs not found\n", connector_name);
+		return false;
+	}
+
+	ret = igt_debugfs_simple_read(fd, DEBUGFS_EDP_PSR_CAP, buf, sizeof(buf));
+	igt_assert_f(ret >= 0, "Reading %s for connector %s failed.\n",
+		     DEBUGFS_EDP_PSR_CAP, connector_name);
+	close(fd);
+
+	if (ret < 1)
+		return false;
+
+	if (mode == PSR_MODE_1)
+		return strstr(buf, "Driver support: yes");
+	else
+		return strstr(buf, "Driver support: yes [0x01]");
+}
diff --git a/lib/igt_amd.h b/lib/igt_amd.h
index f11e36b2..6e465817 100644
--- a/lib/igt_amd.h
+++ b/lib/igt_amd.h
@@ -26,6 +26,7 @@
 #include <stdint.h>
 #include "igt.h"
 #include "igt_fb.h"
+#include "igt_psr.h"
 
 /* Read & Write DSC parameters */
 #define DEBUGFS_DSC_CLOCK_EN "dsc_clock_en"
@@ -42,8 +43,10 @@
 #define DEBUGFS_DP_LINK_SETTINGS "link_settings"
 #define DEBUGFS_HPD_TRIGGER "trigger_hotplug"
 
+/* eDP related */
 #define DEBUGFS_EDP_ILR_SETTING "ilr_setting"
 #define MAX_SUPPORTED_ILR 8
+#define DEBUGFS_EDP_PSR_CAP	"psr_capability"
 
 enum amd_dsc_clock_force {
 	DSC_AUTOMATIC = 0,
@@ -129,11 +132,16 @@ void igt_amd_write_link_settings(
 	int drm_fd, char *connector_name, enum dc_lane_count lane_count,
 	enum dc_link_rate link_rate, enum dc_link_training_type training_type);
 bool igt_amd_output_has_link_settings(int drm_fd, char *connector_name);
+
+/* eDP debugfs helpers */
 void igt_amd_read_ilr_setting(
 	int drm_fd, char *connector_name, int *supported_ilr);
 void igt_amd_write_ilr_setting(
 	int drm_fd, char *connector_name, enum dc_lane_count lane_count,
 	uint8_t link_rate_set);
 bool igt_amd_output_has_ilr_setting(int drm_fd, char *connector_name);
+bool igt_amd_output_has_psr_cap(int drm_fd, char *connector_name);
+bool igt_amd_psr_support_sink(int drm_fd, char *connector_name, enum psr_mode mode);
+bool igt_amd_psr_support_drv(int drm_fd, char *connector_name, enum psr_mode mode);
 
 #endif /* IGT_AMD_H */