drm/omapdrm: Workaround for errata i734 (LCD1 Gamma) in DSS dispc

Workaround for errata i734 in DSS dispc
- LCD1 Gamma Correction Is Not Working When GFX Pipe Is Disabled

For gamma tables to work on LCD1 the GFX plane has to be used at least
once after DSS HW has come out of reset. The workaround sets up a
minimal LCD setup with GFX plane and waits for one vertical sync irq
before disabling the setup and continuing with the context
restore. The physical outputs are gated during the operation.

For details see:
OMAP543x Multimedia Device Silicon Revision 2.0 Silicon Errata
Literature Number: SWPZ037E
Or some other relevant errata document for the DSS IP version.

Signed-off-by: Jyri Sarha <[e-mail]>
Signed-off-by: Tomi Valkeinen <[e-mail]>

drivers/gpu/drm/omapdrm/dss/dispc.c

···
 	bool reverse_ilace_field_order:1;
 
 	bool has_gamma_table:1;
+
+	bool has_gamma_i734_bug:1;
 };
 
 #define DISPC_MAX_NR_FIFOS 5
···
 	.supports_double_pixel	=	true,
 	.reverse_ilace_field_order =	true,
 	.has_gamma_table	=	true,
+	.has_gamma_i734_bug	=	true,
 };
 
 static const struct dispc_features omap54xx_dispc_feats = {
···
 	.supports_double_pixel	=	true,
 	.reverse_ilace_field_order =	true,
 	.has_gamma_table	=	true,
+	.has_gamma_i734_bug	=	true,
 };
 
 static int dispc_init_features(struct platform_device *pdev)
···
 }
 EXPORT_SYMBOL(dispc_free_irq);
 
+/*
+ * Workaround for errata i734 in DSS dispc
+ *  - LCD1 Gamma Correction Is Not Working When GFX Pipe Is Disabled
+ *
+ * For gamma tables to work on LCD1 the GFX plane has to be used at
+ * least once after DSS HW has come out of reset. The workaround
+ * sets up a minimal LCD setup with GFX plane and waits for one
+ * vertical sync irq before disabling the setup and continuing with
+ * the context restore. The physical outputs are gated during the
+ * operation. This workaround requires that gamma table's LOADMODE
+ * is set to 0x2 in DISPC_CONTROL1 register.
+ *
+ * For details see:
+ * OMAP543x Multimedia Device Silicon Revision 2.0 Silicon Errata
+ * Literature Number: SWPZ037E
+ * Or some other relevant errata document for the DSS IP version.
+ */
+
+static const struct dispc_errata_i734_data {
+	struct omap_video_timings timings;
+	struct omap_overlay_info ovli;
+	struct omap_overlay_manager_info mgri;
+	struct dss_lcd_mgr_config lcd_conf;
+} i734 = {
+	.timings = {
+		.x_res = 8, .y_res = 1,
+		.pixelclock = 16000000,
+		.hsw = 8, .hfp = 4, .hbp = 4,
+		.vsw = 1, .vfp = 1, .vbp = 1,
+		.vsync_level = OMAPDSS_SIG_ACTIVE_LOW,
+		.hsync_level = OMAPDSS_SIG_ACTIVE_LOW,
+		.interlace = false,
+		.data_pclk_edge = OMAPDSS_DRIVE_SIG_RISING_EDGE,
+		.de_level = OMAPDSS_SIG_ACTIVE_HIGH,
+		.sync_pclk_edge = OMAPDSS_DRIVE_SIG_RISING_EDGE,
+		.double_pixel = false,
+	},
+	.ovli = {
+		.screen_width = 1,
+		.width = 1, .height = 1,
+		.color_mode = OMAP_DSS_COLOR_RGB24U,
+		.rotation = OMAP_DSS_ROT_0,
+		.rotation_type = OMAP_DSS_ROT_DMA,
+		.mirror = 0,
+		.pos_x = 0, .pos_y = 0,
+		.out_width = 0, .out_height = 0,
+		.global_alpha = 0xff,
+		.pre_mult_alpha = 0,
+		.zorder = 0,
+	},
+	.mgri = {
+		.default_color = 0,
+		.trans_enabled = false,
+		.partial_alpha_enabled = false,
+		.cpr_enable = false,
+	},
+	.lcd_conf = {
+		.io_pad_mode = DSS_IO_PAD_MODE_BYPASS,
+		.stallmode = false,
+		.fifohandcheck = false,
+		.clock_info = {
+			.lck_div = 1,
+			.pck_div = 2,
+		},
+		.video_port_width = 24,
+		.lcden_sig_polarity = 0,
+	},
+};
+
+static struct i734_buf {
+	size_t size;
+	dma_addr_t paddr;
+	void *vaddr;
+} i734_buf;
+
+static int dispc_errata_i734_wa_init(void)
+{
+	if (!dispc.feat->has_gamma_i734_bug)
+		return 0;
+
+	i734_buf.size = i734.ovli.width * i734.ovli.height *
+		color_mode_to_bpp(i734.ovli.color_mode) / 8;
+
+	i734_buf.vaddr = dma_alloc_writecombine(&dispc.pdev->dev, i734_buf.size,
+						&i734_buf.paddr, GFP_KERNEL);
+	if (!i734_buf.vaddr) {
+		dev_err(&dispc.pdev->dev, "%s: dma_alloc_writecombine failed",
+			__func__);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static void dispc_errata_i734_wa_fini(void)
+{
+	if (!dispc.feat->has_gamma_i734_bug)
+		return;
+
+	dma_free_writecombine(&dispc.pdev->dev, i734_buf.size, i734_buf.vaddr,
+			      i734_buf.paddr);
+}
+
+static void dispc_errata_i734_wa(void)
+{
+	u32 framedone_irq = dispc_mgr_get_framedone_irq(OMAP_DSS_CHANNEL_LCD);
+	struct omap_overlay_info ovli;
+	struct dss_lcd_mgr_config lcd_conf;
+	u32 gatestate;
+	unsigned int count;
+
+	if (!dispc.feat->has_gamma_i734_bug)
+		return;
+
+	gatestate = REG_GET(DISPC_CONFIG, 8, 4);
+
+	ovli = i734.ovli;
+	ovli.paddr = i734_buf.paddr;
+	lcd_conf = i734.lcd_conf;
+
+	/* Gate all LCD1 outputs */
+	REG_FLD_MOD(DISPC_CONFIG, 0x1f, 8, 4);
+
+	/* Setup and enable GFX plane */
+	dispc_ovl_set_channel_out(OMAP_DSS_GFX, OMAP_DSS_CHANNEL_LCD);
+	dispc_ovl_setup(OMAP_DSS_GFX, &ovli, false, &i734.timings, false);
+	dispc_ovl_enable(OMAP_DSS_GFX, true);
+
+	/* Set up and enable display manager for LCD1 */
+	dispc_mgr_setup(OMAP_DSS_CHANNEL_LCD, &i734.mgri);
+	dispc_calc_clock_rates(dss_get_dispc_clk_rate(),
+			       &lcd_conf.clock_info);
+	dispc_mgr_set_lcd_config(OMAP_DSS_CHANNEL_LCD, &lcd_conf);
+	dispc_mgr_set_timings(OMAP_DSS_CHANNEL_LCD, &i734.timings);
+
+	dispc_clear_irqstatus(framedone_irq);
+
+	/* Enable and shut the channel to produce just one frame */
+	dispc_mgr_enable(OMAP_DSS_CHANNEL_LCD, true);
+	dispc_mgr_enable(OMAP_DSS_CHANNEL_LCD, false);
+
+	/* Busy wait for framedone. We can't fiddle with irq handlers
+	 * in PM resume. Typically the loop runs less than 5 times and
+	 * waits less than a micro second.
+	 */
+	count = 0;
+	while (!(dispc_read_irqstatus() & framedone_irq)) {
+		if (count++ > 10000) {
+			dev_err(&dispc.pdev->dev, "%s: framedone timeout\n",
+				__func__);
+			break;
+		}
+	}
+	dispc_ovl_enable(OMAP_DSS_GFX, false);
+
+	/* Clear all irq bits before continuing */
+	dispc_clear_irqstatus(0xffffffff);
+
+	/* Restore the original state to LCD1 output gates */
+	REG_FLD_MOD(DISPC_CONFIG, gatestate, 8, 4);
+}
+
 /* DISPC HW IP initialisation */
 static int dispc_bind(struct device *dev, struct device *master, void *data)
 {
···
 	spin_lock_init(&dispc.control_lock);
 
 	r = dispc_init_features(dispc.pdev);
+	if (r)
+		return r;
+
+	r = dispc_errata_i734_wa_init();
 	if (r)
 		return r;
 
···
 			       void *data)
 {
 	pm_runtime_disable(dev);
+
+	dispc_errata_i734_wa_fini();
 }
 
 static const struct component_ops dispc_component_ops = {
···
 	 */
 	if (REG_GET(DISPC_CONFIG, 2, 1) != OMAP_DSS_LOAD_FRAME_ONLY) {
 		_omap_dispc_initial_config();
+
+		dispc_errata_i734_wa();
 
 		dispc_restore_context();