drm: apple: support ProMotion variable refresh rate

drivers/gpu/drm/apple/dcp.c

@@ -656,6 +656,7 @@ static int dcp_register_typec_routes(struct apple_dcp *dcp)
 	return 0;
 }
 
+
 /* copied and simplified from drm_vblank.c */
 static void send_vblank_event(struct drm_device *dev,
 		struct drm_pending_vblank_event *e,

drivers/gpu/drm/apple/iomfb.c

@@ -406,6 +406,8 @@ int dcp_get_modes(struct drm_connector *connector)
 
 	struct drm_device *dev = connector->dev;
 	struct drm_display_mode *mode;
+	u16 min_vfreq = 0, max_vfreq = 0;
+	bool vrr_capable = false;
 	int i;
 
 	/* A Type-C port has no pipeline while the fabric is moving it. */
@@ -414,6 +416,16 @@ int dcp_get_modes(struct drm_connector *connector)
 	dcp = platform_get_drvdata(pdev);
 
 	for (i = 0; i < dcp->nr_modes; ++i) {
+		if (dcp->modes[i].vrr) {
+			u16 lo = dcp->modes[i].min_vrr >> 16;
+			u16 hi = dcp->modes[i].max_vrr >> 16;
+
+			if (!min_vfreq || lo < min_vfreq)
+				min_vfreq = lo;
+			if (hi > max_vfreq)
+				max_vfreq = hi;
+		}
+		vrr_capable |= dcp->modes[i].vrr;
 		mode = drm_mode_duplicate(dev, &dcp->modes[i].mode);
 
 		if (!mode) {
@@ -423,6 +435,8 @@ int dcp_get_modes(struct drm_connector *connector)
 
 		drm_mode_probed_add(connector, mode);
 	}
+	drm_connector_set_vrr_capable_property(connector, vrr_capable);
+
 	if (dcp->nr_modes && dcp->dcpavserv.enabled &&
 	    !apple_connector->drm_edid) {
 		const struct drm_edid *edid;
@@ -437,6 +451,18 @@ int dcp_get_modes(struct drm_connector *connector)
 	if (dcp->nr_modes && apple_connector->drm_edid)
 		drm_edid_connector_update(connector, apple_connector->drm_edid);
 
+	/*
+	 * An internal panel has no EDID, so nothing fills in the refresh range
+	 * that userspace needs before it will drive VRR. Supply the range DCP
+	 * reported for the mode. This has to follow the EDID update, which
+	 * resets display_info.
+	 */
+	if (vrr_capable && max_vfreq &&
+	    !connector->display_info.monitor_range.max_vfreq) {
+		connector->display_info.monitor_range.min_vfreq = min_vfreq;
+		connector->display_info.monitor_range.max_vfreq = max_vfreq;
+	}
+
 	return dcp->nr_modes;
 }
 

drivers/gpu/drm/apple/iomfb_template.c

@@ -4,6 +4,7 @@
  * Copyright The Asahi Linux Contributors
  */
 
+#include <clocksource/arm_arch_timer.h>
 #include <linux/align.h>
 #include <linux/bitmap.h>
 #include <linux/clk.h>
@@ -34,6 +35,9 @@
 /* Register defines used in bandwidth setup structure */
 #define REG_DOORBELL_BIT(idx) (2 + (idx))
 
+static_assert(offsetof(struct DCP_FW_NAME(dcp_swap), timestamp[6]) == 0x30);
+static_assert(offsetof(struct DCP_FW_NAME(dcp_swap), flags1) == 0x40);
+
 struct dcp_wait_cookie {
 	struct kref refcount;
 	struct completion done;
@@ -567,7 +571,9 @@ static bool dcpep_process_chunks(struct apple_dcp *dcp,
 	if (!strcmp(req->key, "TimingElements")) {
 		dcp->modes = enumerate_modes(&ctx, &dcp->nr_modes,
 					     dcp->width_mm, dcp->height_mm,
-					     dcp->notch_height);
+					     dcp->notch_height,
+					     dcp->fixed_connector_type ==
+						     DRM_MODE_CONNECTOR_eDP);
 
 		if (IS_ERR(dcp->modes)) {
 			dev_warn(dcp->dev, "failed to parse modes\n");
@@ -1152,6 +1158,7 @@ static void dcp_swapped(struct apple_dcp *dcp, void *data, void *cookie)
 		return;
 	}
 	dcp->swap_start = ktime_get();
+	dcp->swap_submit_timestamp = arch_timer_read_counter();
 
 	while (!list_empty(&dcp->swapped_out_fbs)) {
 		struct dcp_fb_reference *entry;
@@ -1198,6 +1205,35 @@ static void complete_set_digital_out_mode(struct apple_dcp *dcp, void *data,
 	}
 }
 
+/* DCP applies Adaptive Sync changes when the display mode is reselected. */
+static void dcp_on_set_adaptive_sync(struct apple_dcp *dcp, void *out,
+				     void *cookie)
+{
+	dcp_set_digital_out_mode(dcp, false, &dcp->mode,
+				 complete_set_digital_out_mode, cookie);
+}
+
+static void dcp_set_adaptive_sync(struct apple_dcp *dcp, u32 min_vrr,
+				  void *cookie)
+{
+	struct dcp_set_parameter_dcp param = {
+		.param = IOMFBPARAM_ADAPTIVE_SYNC,
+		.value = {
+			min_vrr, /* minRR, 16.16 fixed-point Hz */
+			0,       /* mediaTargetRate */
+			0,       /* fractional rate */
+		},
+#if DCP_FW_VER >= DCP_FW_VERSION(13, 2, 0)
+		.count = 3,
+#else
+		.count = 1,
+#endif
+	};
+
+	dcp_set_parameter_dcp(dcp, false, &param, dcp_on_set_adaptive_sync,
+			      cookie);
+}
+
 int DCP_FW_NAME(iomfb_modeset)(struct apple_dcp *dcp,
 			       struct drm_crtc_state *crtc_state)
 {
@@ -1237,8 +1273,8 @@ int DCP_FW_NAME(iomfb_modeset)(struct apple_dcp *dcp,
 		.timing_mode_id = mode->timing_mode_id
 	};
 
-	/* Keep track of suspected vrr modes */
-	dcp->use_timestamps = mode->vrr;
+	/* Built-in ProMotion panels require timestamps even in fixed-120 mode. */
+	dcp->use_timestamps = mode->vrr && dcp->main_display;
 
 	cookie = kzalloc(sizeof(*cookie), GFP_KERNEL);
 	if (!cookie) {
@@ -1251,9 +1287,15 @@ int DCP_FW_NAME(iomfb_modeset)(struct apple_dcp *dcp,
 	kref_get(&cookie->refcount);
 
 	dcp->during_modeset = true;
+	dcp->swap_submit_timestamp = 0;
 
-	dcp_set_digital_out_mode(dcp, false, &dcp->mode,
-				 complete_set_digital_out_mode, cookie);
+	if (mode->vrr)
+		dcp_set_adaptive_sync(dcp,
+				      crtc_state->vrr_enabled ? mode->min_vrr : 0,
+				      cookie);
+	else
+		dcp_set_digital_out_mode(dcp, false, &dcp->mode,
+					 complete_set_digital_out_mode, cookie);
 
 	/*
 	 * The DCP firmware has an internal timeout of ~8 seconds for
@@ -1263,7 +1305,6 @@ int DCP_FW_NAME(iomfb_modeset)(struct apple_dcp *dcp,
 	ret = wait_for_completion_timeout(&cookie->done,
 					  msecs_to_jiffies(8500));
 
-	kref_put(&cookie->refcount, release_wait_cookie);
 	dcp->during_modeset = false;
 
 	if (dcp->pending_hotplug) {
@@ -1287,18 +1328,21 @@ int DCP_FW_NAME(iomfb_modeset)(struct apple_dcp *dcp,
 
 	if (ret == 0) {
 		dev_info(dcp->dev, "set_digital_out_mode timed out\n");
+		kref_put(&cookie->refcount, release_wait_cookie);
 		return -EIO;
 	} else if (ret < 0) {
 		dev_info(dcp->dev,
 			 "waiting on set_digital_out_mode failed:%d\n", ret);
+		kref_put(&cookie->refcount, release_wait_cookie);
 		return -EIO;
-
-	} else if (ret > 0) {
+	} else {
 		dev_dbg(dcp->dev,
 			"set_digital_out_mode finished with %d to spare\n",
 			jiffies_to_msecs(ret));
 	}
+	kref_put(&cookie->refcount, release_wait_cookie);
 	dcp->valid_mode = true;
+	dcp->vrr_enabled = mode->vrr && crtc_state->vrr_enabled;
 
 	return 0;
 }
@@ -1405,14 +1449,26 @@ void DCP_FW_NAME(iomfb_flush)(struct apple_dcp *dcp, struct drm_crtc *crtc, stru
 		req->clear = 1;
 	}
 
-	if (has_surface && dcp->use_timestamps) {
+	if (has_surface && (dcp->use_timestamps || dcp->vrr_enabled)) {
+		u64 submit_timestamp = dcp->swap_submit_timestamp;
+		u64 timestamp = arch_timer_read_counter();
+
 		/*
-		 * Fake timstamps to get 120hz refresh rate. It looks
-		 * like the actual value does not matter, as long  as it is non zero.
+		 * IOMobileFramebuffer uses Mach continuous-time values here. On
+		 * Apple Silicon that is the ARM architectural counter. Empirical
+		 * testing shows that using the current submission time together
+		 * with the previous accepted swap makes DCP follow swap pacing.
 		 */
-		req->swap.ts1 = 120;
-		req->swap.ts2 = 120;
-		req->swap.ts3 = 120;
+		if (!submit_timestamp)
+			submit_timestamp = timestamp;
+
+		/* Firmware 12.x/13.x requires timestamp types 1, 2, and 7. */
+		req->swap.timestamp[0] = timestamp;
+		req->swap.timestamp[1] = submit_timestamp;
+		req->swap.timestamp[6] = timestamp;
+
+		trace_iomfb_vrr_timestamps(dcp, dcp->vrr_enabled, timestamp,
+					   submit_timestamp);
 	}
 
 	/* These fields should be set together */

drivers/gpu/drm/apple/iomfb_template.h

@@ -18,14 +18,8 @@
 #include "version_utils.h"
 
 struct DCP_FW_NAME(dcp_swap) {
-	u64 ts1;
-	u64 ts2;
-
-	u64 unk_10;
-	u64 unk_18;
-	u64 ts64_unk;
-	u64 unk_28;
-	u64 ts3;
+	/* IOMobileFramebuffer timestamp types 1 through 7, in wire order. */
+	u64 timestamp[7];
 	u64 unk_38;
 
 	u64 flags1;

drivers/gpu/drm/apple/parser.c

@@ -443,7 +443,7 @@ static u32 calculate_clock(struct dimension *horiz, struct dimension *vert)
 
 static int parse_mode(struct dcp_parse_ctx *handle,
 		      struct dcp_display_mode *out, s64 *score, int width_mm,
-		      int height_mm, unsigned notch_height)
+		      int height_mm, unsigned notch_height, bool internal)
 {
 	int ret = 0;
 	struct iterator it;
@@ -515,20 +515,21 @@ static int parse_mode(struct dcp_parse_ctx *handle,
 		return -EINVAL;
 
 	/*
-	* HACK:
-	* Mark the 120 Hz mode on j314/j316 (identified by resolution) as vrr.
-	* We still do not know how to drive VRR but at least seetinng timestamps
-	* in the the swap_surface message to non-zero values drives the display
-	* at 120 fps.
-	*/
-	if (vert.precise_sync_rate >> 16 == 120 &&
-	    ((horiz.active == 3024 && vert.active == 1964) ||
-	     (horiz.active == 3456 && vert.active == 2234)))
+	 * An internal ProMotion panel carries no EDID or DisplayID, so DCP
+	 * reports no adaptive-sync range for it. Assume the ProMotion floor of
+	 * 24 Hz up to whatever rate the mode itself advertises.
+	 */
+	if (internal && vert.precise_sync_rate >> 16 == 120) {
+		out->min_vrr = 24 << 16;
+		out->max_vrr = vert.precise_sync_rate;
 		out->vrr = true;
+	}
 
-	if (min_vrr && max_vrr) {
+	/* Refresh rates are reported by DCP as 16.16 fixed-point Hz. */
+	if (min_vrr && max_vrr > min_vrr) {
 		out->min_vrr = min_vrr;
 		out->max_vrr = max_vrr;
+		out->vrr = true;
 	}
 
 	vert.active -= notch_height;
@@ -568,7 +569,8 @@ static int parse_mode(struct dcp_parse_ctx *handle,
 
 struct dcp_display_mode *enumerate_modes(struct dcp_parse_ctx *handle,
 					 unsigned int *count, int width_mm,
-					 int height_mm, unsigned notch_height)
+					 int height_mm, unsigned notch_height,
+					 bool internal)
 {
 	struct iterator it;
 	int ret;
@@ -590,7 +592,8 @@ struct dcp_display_mode *enumerate_modes(struct dcp_parse_ctx *handle,
 
 	for (; it.idx < it.len; ++it.idx) {
 		mode = &modes[*count];
-		ret = parse_mode(it.handle, mode, &score, width_mm, height_mm, notch_height);
+		ret = parse_mode(it.handle, mode, &score, width_mm, height_mm,
+				 notch_height, internal);
 
 		/* Errors for a single mode are recoverable -- just skip it. */
 		if (ret)

drivers/gpu/drm/apple/parser.h

@@ -104,7 +104,8 @@ struct dimension {
 int parse(const void *blob, size_t size, struct dcp_parse_ctx *ctx);
 struct dcp_display_mode *enumerate_modes(struct dcp_parse_ctx *handle,
 					 unsigned int *count, int width_mm,
-					 int height_mm, unsigned notch_height);
+					 int height_mm, unsigned notch_height,
+					 bool internal);
 int parse_display_attributes(struct dcp_parse_ctx *handle, int *width_mm,
 			     int *height_mm);
 int parse_epic_service_init(struct dcp_parse_ctx *handle, const char **name,

drivers/gpu/drm/apple/trace.h

@@ -263,6 +263,27 @@ TRACE_EVENT(iomfb_swap_submit,
 		      __entry->swap_id)
 );
 
+TRACE_EVENT(iomfb_vrr_timestamps,
+	    TP_PROTO(struct apple_dcp *dcp, bool enabled, u64 timestamp,
+		     u64 submit_timestamp),
+	    TP_ARGS(dcp, enabled, timestamp, submit_timestamp),
+	    TP_STRUCT__entry(
+			     __field(u64, dcp)
+			     __field(bool, enabled)
+			     __field(u64, timestamp)
+			     __field(u64, submit_timestamp)
+	    ),
+	    TP_fast_assign(
+			   __entry->dcp = (u64)dcp;
+			   __entry->enabled = enabled;
+			   __entry->timestamp = timestamp;
+			   __entry->submit_timestamp = submit_timestamp;
+	    ),
+	    TP_printk("dcp=%llx, enabled=%u, timestamp=%llu, previous=%llu",
+		      __entry->dcp, __entry->enabled, __entry->timestamp,
+		      __entry->submit_timestamp)
+);
+
 TRACE_EVENT(iomfb_swap_complete,
 	    TP_PROTO(struct apple_dcp *dcp, u32 swap_id),
 	    TP_ARGS(dcp, swap_id),