[PATCH 3/4] drm/omapdrm: Work-a-round for errata i734 (LCD1 Gamma) in DSS dispc

[Jyri Sarha <jsarha@ti.com>]

Work-a-round 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 work-a-round 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
work-a-round 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.

Signed-off-by: Jyri Sarha <jsarha@ti.com>
---
 drivers/gpu/drm/omapdrm/dss/dispc.c        | 166 +++++++++++++++++++++++++++++
 drivers/gpu/drm/omapdrm/dss/dss_features.c |   2 +
 drivers/gpu/drm/omapdrm/dss/dss_features.h |   1 +
 3 files changed, 169 insertions(+)

diff --git a/drivers/gpu/drm/omapdrm/dss/dispc.c b/drivers/gpu/drm/omapdrm/dss/dispc.c
index 87dde05..3608cf2 100644
--- a/drivers/gpu/drm/omapdrm/dss/dispc.c
+++ b/drivers/gpu/drm/omapdrm/dss/dispc.c
@@ -4201,6 +4201,164 @@ void dispc_free_irq(void *dev_id)
 }
 EXPORT_SYMBOL(dispc_free_irq);
 
+/*
+ * Work-a-round 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 work-a-round
+ * 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 work-a-round 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 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;
+	struct i734_buf {
+		dma_addr_t paddr;
+		void *vaddr;
+	} buf;
+} 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 int dispc_errata_i734_wa_init(void)
+{
+	size_t buff_size = i734.ovli.width * i734.ovli.height *
+		color_mode_to_bpp(i734.ovli.color_mode) / 8;
+
+	if (!dss_has_feature(FEAT_GAMMA_I734_BUG))
+		return 0;
+
+	i734.buf.vaddr = dma_alloc_writecombine(&dispc.pdev->dev, buff_size,
+						&i734.buf.paddr, GFP_KERNEL);
+	if (WARN_ON(IS_ERR(i734.buf.vaddr)))
+		return PTR_ERR(i734.buf.vaddr);
+
+	i734.ovli.paddr = i734.buf.paddr;
+
+	return 0;
+}
+
+static void dispc_errata_i734_wa_fini(void)
+{
+	size_t buff_size = i734.ovli.width * i734.ovli.height *
+		color_mode_to_bpp(i734.ovli.color_mode) / 8;
+
+	if (!dss_has_feature(FEAT_GAMMA_I734_BUG))
+		return;
+
+	dma_free_writecombine(&dispc.pdev->dev, buff_size, i734.buf.vaddr,
+			      i734.buf.paddr);
+}
+
+static void dispc_errata_i734_wa(void)
+{
+	u32 vsync_irq = dispc_mgr_get_vsync_irq(OMAP_DSS_CHANNEL_LCD);
+	u32 framedone_irq = dispc_mgr_get_framedone_irq(OMAP_DSS_CHANNEL_LCD);
+	u32 gatestate = REG_GET(DISPC_CONTROL, 8, 4);
+	unsigned int count;
+
+	if (!dss_has_feature(FEAT_GAMMA_I734_BUG))
+		return;
+
+	/* Gate all LCD1 outputs */
+	REG_FLD_MOD(DISPC_CONTROL, 0, 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, &i734.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(),
+			       &i734.lcd_conf.clock_info);
+	dispc_mgr_set_lcd_config(OMAP_DSS_CHANNEL_LCD, &i734.lcd_conf);
+	dispc_mgr_set_timings(OMAP_DSS_CHANNEL_LCD, &i734.timings);
+	dispc_mgr_enable(OMAP_DSS_CHANNEL_LCD, true);
+
+	dispc_clear_irqstatus(vsync_irq | framedone_irq);
+
+	/* Busy wait for vsync (we can't fiddle with irq handlers in resume) */
+	count = 0;
+	while (!(dispc_read_irqstatus() & vsync_irq))
+		if (count++ > 10000) {
+			dev_err(&dispc.pdev->dev, "%s: vsync timeout\n",
+				__func__);
+			break;
+		}
+
+	/* Shut down the WA setup */
+	dispc_mgr_enable(OMAP_DSS_CHANNEL_LCD, false);
+	dispc_ovl_enable(OMAP_DSS_GFX, false);
+	count = 0;
+	while (!(dispc_read_irqstatus() & framedone_irq))
+		if (count++ > 10000) {
+			dev_err(&dispc.pdev->dev, "%s: framedone timeout\n",
+				__func__);
+			break;
+		}
+
+	/* Clear all irq bits before continuing */
+	dispc_clear_irqstatus(0xffffffff);
+
+	/* Restore the original state to LCD1 output gates */
+	REG_FLD_MOD(DISPC_CONTROL, gatestate, 8, 4);
+}
+
 /* DISPC HW IP initialisation */
 static int dispc_bind(struct device *dev, struct device *master, void *data)
 {
@@ -4214,6 +4372,10 @@ static int dispc_bind(struct device *dev, struct device *master, void *data)
 
 	spin_lock_init(&dispc.control_lock);
 
+	r = dispc_errata_i734_wa_init();
+	if (r)
+		return r;
+
 	r = dispc_init_features(dispc.pdev);
 	if (r)
 		return r;
@@ -4282,6 +4444,8 @@ static void dispc_unbind(struct device *dev, struct device *master,
 			       void *data)
 {
 	pm_runtime_disable(dev);
+
+	dispc_errata_i734_wa_fini();
 }
 
 static const struct component_ops dispc_component_ops = {
@@ -4324,6 +4488,8 @@ static int dispc_runtime_resume(struct device *dev)
 	if (REG_GET(DISPC_CONFIG, 2, 1) != OMAP_DSS_LOAD_FRAME_ONLY) {
 		_omap_dispc_initial_config();
 
+		dispc_errata_i734_wa();
+
 		dispc_restore_context();
 
 		dispc_restore_gamma_tables();
diff --git a/drivers/gpu/drm/omapdrm/dss/dss_features.c b/drivers/gpu/drm/omapdrm/dss/dss_features.c
index f77b1c5..3127bd6 100644
--- a/drivers/gpu/drm/omapdrm/dss/dss_features.c
+++ b/drivers/gpu/drm/omapdrm/dss/dss_features.c
@@ -594,6 +594,7 @@ static const enum dss_feat_id omap4_dss_feat_list[] = {
 	FEAT_FIFO_MERGE,
 	FEAT_BURST_2D,
 	FEAT_GAMMA_TABLE,
+	FEAT_GAMMA_I734_BUG,
 };
 
 static const enum dss_feat_id omap5_dss_feat_list[] = {
@@ -617,6 +618,7 @@ static const enum dss_feat_id omap5_dss_feat_list[] = {
 	FEAT_DSI_PHY_DCC,
 	FEAT_MFLAG,
 	FEAT_GAMMA_TABLE,
+	FEAT_GAMMA_I734_BUG,
 };
 
 /* OMAP2 DSS Features */
diff --git a/drivers/gpu/drm/omapdrm/dss/dss_features.h b/drivers/gpu/drm/omapdrm/dss/dss_features.h
index d4d14db..0f74083 100644
--- a/drivers/gpu/drm/omapdrm/dss/dss_features.h
+++ b/drivers/gpu/drm/omapdrm/dss/dss_features.h
@@ -63,6 +63,7 @@ enum dss_feat_id {
 	FEAT_DSI_PHY_DCC,
 	FEAT_MFLAG,
 	FEAT_GAMMA_TABLE,
+	FEAT_GAMMA_I734_BUG,
 };
 
 /* DSS register field id */
-- 
1.9.1

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