drm/sun4i: dsi: Add burst support

The current driver doesn't support the DSI burst operation mode.

Let's add the needed quirks to make it work.
Signed-off-by: Konstantin Sudakov <k.sudakov@integrasources.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Reviewed-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1dcabf2b38d3f0d3387b1cf02575e3d14e3ecd4e.1549896081.git-series.maxime.ripard@bootlin.com

drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c

@@ -24,7 +24,9 @@
 #include <drm/drm_panel.h>
 #include <drm/drm_probe_helper.h>
 
+#include "sun4i_crtc.h"
 #include "sun4i_drv.h"
+#include "sun4i_tcon.h"
 #include "sun6i_mipi_dsi.h"
 
 #include <video/mipi_display.h>
@@ -33,6 +35,8 @@
 #define SUN6I_DSI_CTL_EN			BIT(0)
 
 #define SUN6I_DSI_BASIC_CTL_REG		0x00c
+#define SUN6I_DSI_BASIC_CTL_TRAIL_INV(n)		(((n) & 0xf) << 4)
+#define SUN6I_DSI_BASIC_CTL_TRAIL_FILL		BIT(3)
 #define SUN6I_DSI_BASIC_CTL_HBP_DIS		BIT(2)
 #define SUN6I_DSI_BASIC_CTL_HSA_HSE_DIS		BIT(1)
 #define SUN6I_DSI_BASIC_CTL_VIDEO_BURST		BIT(0)
@@ -153,6 +157,8 @@
 
 #define SUN6I_DSI_CMD_TX_REG(n)		(0x300 + (n) * 0x04)
 
+#define SUN6I_DSI_SYNC_POINT		40
+
 enum sun6i_dsi_start_inst {
 	DSI_START_LPRX,
 	DSI_START_LPTX,
@@ -367,13 +373,70 @@ static u16 sun6i_dsi_get_video_start_delay(struct sun6i_dsi *dsi,
 	return max_t(u16, delay, 1);
 }
 
+static u16 sun6i_dsi_get_line_num(struct sun6i_dsi *dsi,
+				  struct drm_display_mode *mode)
+{
+	struct mipi_dsi_device *device = dsi->device;
+	unsigned int Bpp = mipi_dsi_pixel_format_to_bpp(device->format) / 8;
+
+	return mode->htotal * Bpp / device->lanes;
+}
+
+static u16 sun6i_dsi_get_drq_edge0(struct sun6i_dsi *dsi,
+				   struct drm_display_mode *mode,
+				   u16 line_num, u16 edge1)
+{
+	u16 edge0 = edge1;
+
+	edge0 += (mode->hdisplay + 40) * SUN6I_DSI_TCON_DIV / 8;
+
+	if (edge0 > line_num)
+		return edge0 - line_num;
+
+	return 1;
+}
+
+static u16 sun6i_dsi_get_drq_edge1(struct sun6i_dsi *dsi,
+				   struct drm_display_mode *mode,
+				   u16 line_num)
+{
+	struct mipi_dsi_device *device = dsi->device;
+	unsigned int Bpp = mipi_dsi_pixel_format_to_bpp(device->format) / 8;
+	unsigned int hbp = mode->htotal - mode->hsync_end;
+	u16 edge1;
+
+	edge1 = SUN6I_DSI_SYNC_POINT;
+	edge1 += (mode->hdisplay + hbp + 20) * Bpp / device->lanes;
+
+	if (edge1 > line_num)
+		return line_num;
+
+	return edge1;
+}
+
 static void sun6i_dsi_setup_burst(struct sun6i_dsi *dsi,
 				  struct drm_display_mode *mode)
 {
 	struct mipi_dsi_device *device = dsi->device;
 	u32 val = 0;
 
-	if ((mode->hsync_end - mode->hdisplay) > 20) {
+	if (device->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) {
+		u16 line_num = sun6i_dsi_get_line_num(dsi, mode);
+		u16 edge0, edge1;
+
+		edge1 = sun6i_dsi_get_drq_edge1(dsi, mode, line_num);
+		edge0 = sun6i_dsi_get_drq_edge0(dsi, mode, line_num, edge1);
+
+		regmap_write(dsi->regs, SUN6I_DSI_BURST_DRQ_REG,
+			     SUN6I_DSI_BURST_DRQ_EDGE0(edge0) |
+			     SUN6I_DSI_BURST_DRQ_EDGE1(edge1));
+
+		regmap_write(dsi->regs, SUN6I_DSI_BURST_LINE_REG,
+			     SUN6I_DSI_BURST_LINE_NUM(line_num) |
+			     SUN6I_DSI_BURST_LINE_SYNC_POINT(SUN6I_DSI_SYNC_POINT));
+
+		val = SUN6I_DSI_TCON_DRQ_ENABLE_MODE;
+	} else if ((mode->hsync_end - mode->hdisplay) > 20) {
 		/* Maaaaaagic */
 		u16 drq = (mode->hsync_end - mode->hdisplay) - 20;
 
@@ -390,8 +453,19 @@ static void sun6i_dsi_setup_burst(struct sun6i_dsi *dsi,
 static void sun6i_dsi_setup_inst_loop(struct sun6i_dsi *dsi,
 				      struct drm_display_mode *mode)
 {
+	struct mipi_dsi_device *device = dsi->device;
 	u16 delay = 50 - 1;
 
+	if (device->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) {
+		delay = (mode->htotal - mode->hdisplay) * 150;
+		delay /= (mode->clock / 1000) * 8;
+		delay -= 50;
+	}
+
+	regmap_write(dsi->regs, SUN6I_DSI_INST_LOOP_SEL_REG,
+		     2 << (4 * DSI_INST_ID_LP11) |
+		     3 << (4 * DSI_INST_ID_DLY));
+
 	regmap_write(dsi->regs, SUN6I_DSI_INST_LOOP_NUM_REG(0),
 		     SUN6I_DSI_INST_LOOP_NUM_N0(50 - 1) |
 		     SUN6I_DSI_INST_LOOP_NUM_N1(delay));
@@ -457,45 +531,59 @@ static void sun6i_dsi_setup_timings(struct sun6i_dsi *dsi,
 {
 	struct mipi_dsi_device *device = dsi->device;
 	unsigned int Bpp = mipi_dsi_pixel_format_to_bpp(device->format) / 8;
-	u16 hbp, hfp, hsa, hblk, vblk;
+	u16 hbp = 0, hfp = 0, hsa = 0, hblk = 0, vblk = 0;
+	u32 basic_ctl = 0;
 	size_t bytes;
 	u8 *buffer;
 
 	/* Do all timing calculations up front to allocate buffer space */
 
+	if (device->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) {
+		hblk = mode->hdisplay * Bpp;
+		basic_ctl = SUN6I_DSI_BASIC_CTL_VIDEO_BURST |
+			    SUN6I_DSI_BASIC_CTL_HSA_HSE_DIS |
+			    SUN6I_DSI_BASIC_CTL_HBP_DIS;
+
+		if (device->lanes == 4)
+			basic_ctl |= SUN6I_DSI_BASIC_CTL_TRAIL_FILL |
+				     SUN6I_DSI_BASIC_CTL_TRAIL_INV(0xc);
+	} else {
 		/*
-	 * A sync period is composed of a blanking packet (4 bytes +
-	 * payload + 2 bytes) and a sync event packet (4 bytes). Its
-	 * minimal size is therefore 10 bytes
+		 * A sync period is composed of a blanking packet (4
+		 * bytes + payload + 2 bytes) and a sync event packet
+		 * (4 bytes). Its minimal size is therefore 10 bytes
 		 */
 #define HSA_PACKET_OVERHEAD	10
 		hsa = max((unsigned int)HSA_PACKET_OVERHEAD,
 			  (mode->hsync_end - mode->hsync_start) * Bpp - HSA_PACKET_OVERHEAD);
 
 		/*
-	 * The backporch is set using a blanking packet (4 bytes +
-	 * payload + 2 bytes). Its minimal size is therefore 6 bytes
+		 * The backporch is set using a blanking packet (4
+		 * bytes + payload + 2 bytes). Its minimal size is
+		 * therefore 6 bytes
 		 */
 #define HBP_PACKET_OVERHEAD	6
 		hbp = max((unsigned int)HBP_PACKET_OVERHEAD,
 			  (mode->htotal - mode->hsync_end) * Bpp - HBP_PACKET_OVERHEAD);
 
 		/*
-	 * The frontporch is set using a blanking packet (4 bytes +
-	 * payload + 2 bytes). Its minimal size is therefore 6 bytes
+		 * The frontporch is set using a blanking packet (4
+		 * bytes + payload + 2 bytes). Its minimal size is
+		 * therefore 6 bytes
 		 */
 #define HFP_PACKET_OVERHEAD	6
 		hfp = max((unsigned int)HFP_PACKET_OVERHEAD,
 			  (mode->hsync_start - mode->hdisplay) * Bpp - HFP_PACKET_OVERHEAD);
 
 		/*
-	 * The blanking is set using a sync event (4 bytes) and a
-	 * blanking packet (4 bytes + payload + 2 bytes). Its minimal
-	 * size is therefore 10 bytes.
+		 * The blanking is set using a sync event (4 bytes)
+		 * and a blanking packet (4 bytes + payload + 2
+		 * bytes). Its minimal size is therefore 10 bytes.
 		 */
 #define HBLK_PACKET_OVERHEAD	10
 		hblk = max((unsigned int)HBLK_PACKET_OVERHEAD,
-		   (mode->htotal - (mode->hsync_end - mode->hsync_start)) * Bpp - HBLK_PACKET_OVERHEAD);
+			   (mode->htotal - (mode->hsync_end - mode->hsync_start)) * Bpp -
+			   HBLK_PACKET_OVERHEAD);
 
 		/*
 		 * And I'm not entirely sure what vblk is about. The driver in
@@ -504,6 +592,7 @@ static void sun6i_dsi_setup_timings(struct sun6i_dsi *dsi,
 		 * case) even with a 4 lanes screen seems to work...
 		 */
 		vblk = 0;
+	}
 
 	/* How many bytes do we need to send all payloads? */
 	bytes = max_t(size_t, max(max(hfp, hblk), max(hsa, hbp)), vblk);
@@ -511,7 +600,7 @@ static void sun6i_dsi_setup_timings(struct sun6i_dsi *dsi,
 	if (WARN_ON(!buffer))
 		return;
 
-	regmap_write(dsi->regs, SUN6I_DSI_BASIC_CTL_REG, 0);
+	regmap_write(dsi->regs, SUN6I_DSI_BASIC_CTL_REG, basic_ctl);
 
 	regmap_write(dsi->regs, SUN6I_DSI_SYNC_HSS_REG,
 		     sun6i_dsi_build_sync_pkt(MIPI_DSI_H_SYNC_START,