drm: apple: Add CRTC CRC support

The DCP firmware has CRC support. While this is not yet reverse
engineering report always 0 to at least be able to run tests from
igt-gpu-tools with "--skip-crc-compare".

Signed-off-by: Janne Grunau <j@jannau.net>

Author: jannau

drivers/gpu/drm/apple/apple_drv.c

@@ -261,13 +261,70 @@ static void apple_crtc_cleanup(struct drm_crtc *crtc)
 	kfree(to_apple_crtc(crtc));
 }
 
+static int apple_crtc_parse_crc_source(const char *source, bool *enabled)
+{
+	int ret = 0;
+
+	if (!source) {
+		*enabled = false;
+	} else if (strcmp(source, "auto") == 0) {
+		*enabled = true;
+	} else {
+		*enabled = false;
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
+static int apple_crtc_set_crc_source(struct drm_crtc *crtc, const char *source)
+{
+	bool enabled = false;
+
+	int ret = apple_crtc_parse_crc_source(source, &enabled);
+
+	if (!ret)
+		dcp_set_crc(crtc, enabled);
+
+	return ret;
+}
+
+static int apple_crtc_verify_crc_source(struct drm_crtc *crtc,
+					const char *source,
+					size_t *values_cnt)
+{
+	bool enabled;
+
+	if (apple_crtc_parse_crc_source(source, &enabled) < 0) {
+		pr_warn("dcp: Invalid CRC source name %s\n", source);
+		return -EINVAL;
+	}
+
+	*values_cnt = 1;
+
+	return 0;
+}
+
+static const char * const apple_crtc_crc_sources[] = {"auto"};
+
+static const char *const * apple_crtc_get_crc_sources(struct drm_crtc *crtc,
+						      size_t *count)
+{
+	*count = ARRAY_SIZE(apple_crtc_crc_sources);
+	return apple_crtc_crc_sources;
+}
+
 static const struct drm_crtc_funcs apple_crtc_funcs = {
 	.atomic_destroy_state	= drm_atomic_helper_crtc_destroy_state,
 	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
 	.destroy		= apple_crtc_cleanup,
 	.page_flip		= drm_atomic_helper_page_flip,
 	.reset			= drm_atomic_helper_crtc_reset,
 	.set_config             = drm_atomic_helper_set_config,
+	.set_crc_source		= apple_crtc_set_crc_source,
+	.verify_crc_source	= apple_crtc_verify_crc_source,
+	.get_crc_sources	= apple_crtc_get_crc_sources,
+
 };
 
 static const struct drm_mode_config_funcs apple_mode_config_funcs = {

drivers/gpu/drm/apple/dcp-internal.h

@@ -198,6 +198,9 @@ struct apple_dcp {
 	/* clear all surfaces on init */
 	bool surfaces_cleared;
 
+	/* enable CRC calculation */
+	bool crc_enabled;
+
 	/* Modes valid for the connected display */
 	struct dcp_display_mode *modes;
 	unsigned int nr_modes;

drivers/gpu/drm/apple/dcp.c

@@ -191,6 +191,17 @@ bool dcp_has_panel(struct apple_dcp *dcp)
 	return dcp->panel.width_mm > 0;
 }
 
+int dcp_set_crc(struct drm_crtc *crtc, bool enabled)
+{
+	struct apple_crtc *ac = to_apple_crtc(crtc);
+	struct apple_dcp *dcp = platform_get_drvdata(ac->dcp);
+
+	dcp->crc_enabled = enabled;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dcp_set_crc);
+
 /*
  * Helper to send a DRM vblank event. We do not know how call swap_submit_dcp
  * without surfaces. To avoid timeouts in drm_atomic_helper_wait_for_vblanks

drivers/gpu/drm/apple/dcp.h

@@ -31,6 +31,7 @@ struct apple_encoder {
 
 void dcp_poweroff(struct platform_device *pdev);
 void dcp_poweron(struct platform_device *pdev);
+int dcp_set_crc(struct drm_crtc *crtc, bool enabled);
 int dcp_crtc_atomic_check(struct drm_crtc *crtc, struct drm_atomic_state *state);
 int dcp_get_connector_type(struct platform_device *pdev);
 void dcp_link(struct platform_device *pdev, struct apple_crtc *apple,

drivers/gpu/drm/apple/iomfb_template.c

@@ -125,6 +125,10 @@ static void dcpep_cb_swap_complete(struct apple_dcp *dcp,
 	dcp->last_swap_id = resp->swap_id;
 
 	dcp_drm_crtc_page_flip(dcp, now);
+	if (dcp->crc_enabled) {
+		u32 crc32 = 0;
+		drm_crtc_add_crc_entry(&dcp->crtc->base, true, resp->swap_id, &crc32);
+	}
 }
 
 /* special */