drm/omapdrm: Add gamma table support to DSS dispc

Add gamma table support to DSS dispc.

DSS driver initializes the default gamma table at component bind time
and holds a copy of all gamma tables in its internal data structure.

Each call to dispc_mgr_set_gamma() updates the internal table and
triggers write to the HW, if it is enabled. The tables are restored to
HW in PM resume callback. The drivers internal data structure match
the HW tables in size and in number of significant bits per color
component. The dispc_mgr_set_gamma() converts the size of any given
table for the internal data structure using linear interpolation.
Default gamma table is restored if NULL is given in place of gamma
lut.

dispc_mgr_gamma_size() gives HW gamma table size for the channel and
returns 0 if gamma table is not supported by the HW or the DSS driver.

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

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

···
 	 * never both, we can just use this flag for now.
 	 */
 	bool reverse_ilace_field_order:1;
+
+	bool has_gamma_table:1;
 };
 
 #define DISPC_MAX_NR_FIFOS 5
+#define DISPC_MAX_CHANNEL_GAMMA 4
 
 static struct {
 	struct platform_device *pdev;
···
 
 	bool		ctx_valid;
 	u32		ctx[DISPC_SZ_REGS / sizeof(u32)];
+
+	u32 *gamma_table[DISPC_MAX_CHANNEL_GAMMA];
 
 	const struct dispc_features *feat;
 
···
 	u8 low;
 };
 
+struct dispc_gamma_desc {
+	u32 len;
+	u32 bits;
+	u16 reg;
+	bool has_index;
+};
+
 static const struct {
 	const char *name;
 	u32 vsync_irq;
 	u32 framedone_irq;
 	u32 sync_lost_irq;
+	struct dispc_gamma_desc gamma;
 	struct dispc_reg_field reg_desc[DISPC_MGR_FLD_NUM];
 } mgr_desc[] = {
 	[OMAP_DSS_CHANNEL_LCD] = {
···
 		.vsync_irq	= DISPC_IRQ_VSYNC,
 		.framedone_irq	= DISPC_IRQ_FRAMEDONE,
 		.sync_lost_irq	= DISPC_IRQ_SYNC_LOST,
+		.gamma		= {
+			.len	= 256,
+			.bits	= 8,
+			.reg	= DISPC_GAMMA_TABLE0,
+			.has_index = true,
+		},
 		.reg_desc	= {
 			[DISPC_MGR_FLD_ENABLE]		= { DISPC_CONTROL,  0,  0 },
 			[DISPC_MGR_FLD_STNTFT]		= { DISPC_CONTROL,  3,  3 },
···
 		.vsync_irq	= DISPC_IRQ_EVSYNC_ODD | DISPC_IRQ_EVSYNC_EVEN,
 		.framedone_irq	= DISPC_IRQ_FRAMEDONETV,
 		.sync_lost_irq	= DISPC_IRQ_SYNC_LOST_DIGIT,
+		.gamma		= {
+			.len	= 1024,
+			.bits	= 10,
+			.reg	= DISPC_GAMMA_TABLE2,
+			.has_index = false,
+		},
 		.reg_desc	= {
 			[DISPC_MGR_FLD_ENABLE]		= { DISPC_CONTROL,  1,  1 },
 			[DISPC_MGR_FLD_STNTFT]		= { },
···
 		.vsync_irq	= DISPC_IRQ_VSYNC2,
 		.framedone_irq	= DISPC_IRQ_FRAMEDONE2,
 		.sync_lost_irq	= DISPC_IRQ_SYNC_LOST2,
+		.gamma		= {
+			.len	= 256,
+			.bits	= 8,
+			.reg	= DISPC_GAMMA_TABLE1,
+			.has_index = true,
+		},
 		.reg_desc	= {
 			[DISPC_MGR_FLD_ENABLE]		= { DISPC_CONTROL2,  0,  0 },
 			[DISPC_MGR_FLD_STNTFT]		= { DISPC_CONTROL2,  3,  3 },
···
 		.vsync_irq	= DISPC_IRQ_VSYNC3,
 		.framedone_irq	= DISPC_IRQ_FRAMEDONE3,
 		.sync_lost_irq	= DISPC_IRQ_SYNC_LOST3,
+		.gamma		= {
+			.len	= 256,
+			.bits	= 8,
+			.reg	= DISPC_GAMMA_TABLE3,
+			.has_index = true,
+		},
 		.reg_desc	= {
 			[DISPC_MGR_FLD_ENABLE]		= { DISPC_CONTROL3,  0,  0 },
 			[DISPC_MGR_FLD_STNTFT]		= { DISPC_CONTROL3,  3,  3 },
···
 	unsigned unit = dss_feat_get_burst_size_unit();
 	/* burst multiplier is always x8 (see dispc_configure_burst_sizes()) */
 	return unit * 8;
-}
-
-void dispc_enable_gamma_table(bool enable)
-{
-	/*
-	 * This is partially implemented to support only disabling of
-	 * the gamma table.
-	 */
-	if (enable) {
-		DSSWARN("Gamma table enabling for TV not yet supported");
-		return;
-	}
-
-	REG_FLD_MOD(DISPC_CONFIG, enable, 9, 9);
 }
 
 static void dispc_mgr_enable_cpr(enum omap_channel channel, bool enable)
···
 	REG_FLD_MOD(DISPC_SYSCONFIG, 1, 4, 3);	/* SIDLEMODE: no idle */
 }
 
+u32 dispc_mgr_gamma_size(enum omap_channel channel)
+{
+	const struct dispc_gamma_desc *gdesc = &mgr_desc[channel].gamma;
+
+	if (!dispc.feat->has_gamma_table)
+		return 0;
+
+	return gdesc->len;
+}
+EXPORT_SYMBOL(dispc_mgr_gamma_size);
+
+static void dispc_mgr_write_gamma_table(enum omap_channel channel)
+{
+	const struct dispc_gamma_desc *gdesc = &mgr_desc[channel].gamma;
+	u32 *table = dispc.gamma_table[channel];
+	unsigned int i;
+
+	DSSDBG("%s: channel %d\n", __func__, channel);
+
+	for (i = 0; i < gdesc->len; ++i) {
+		u32 v = table[i];
+
+		if (gdesc->has_index)
+			v |= i << 24;
+		else if (i == 0)
+			v |= 1 << 31;
+
+		dispc_write_reg(gdesc->reg, v);
+	}
+}
+
+static void dispc_restore_gamma_tables(void)
+{
+	DSSDBG("%s()\n", __func__);
+
+	if (!dispc.feat->has_gamma_table)
+		return;
+
+	dispc_mgr_write_gamma_table(OMAP_DSS_CHANNEL_LCD);
+
+	dispc_mgr_write_gamma_table(OMAP_DSS_CHANNEL_DIGIT);
+
+	if (dss_has_feature(FEAT_MGR_LCD2))
+		dispc_mgr_write_gamma_table(OMAP_DSS_CHANNEL_LCD2);
+
+	if (dss_has_feature(FEAT_MGR_LCD3))
+		dispc_mgr_write_gamma_table(OMAP_DSS_CHANNEL_LCD3);
+}
+
+static const struct drm_color_lut dispc_mgr_gamma_default_lut[] = {
+	{ .red = 0, .green = 0, .blue = 0, },
+	{ .red = U16_MAX, .green = U16_MAX, .blue = U16_MAX, },
+};
+
+void dispc_mgr_set_gamma(enum omap_channel channel,
+			 const struct drm_color_lut *lut,
+			 unsigned int length)
+{
+	const struct dispc_gamma_desc *gdesc = &mgr_desc[channel].gamma;
+	u32 *table = dispc.gamma_table[channel];
+	uint i;
+
+	DSSDBG("%s: channel %d, lut len %u, hw len %u\n", __func__,
+	       channel, length, gdesc->len);
+
+	if (!dispc.feat->has_gamma_table)
+		return;
+
+	if (lut == NULL || length < 2) {
+		lut = dispc_mgr_gamma_default_lut;
+		length = ARRAY_SIZE(dispc_mgr_gamma_default_lut);
+	}
+
+	for (i = 0; i < length - 1; ++i) {
+		uint first = i * (gdesc->len - 1) / (length - 1);
+		uint last = (i + 1) * (gdesc->len - 1) / (length - 1);
+		uint w = last - first;
+		u16 r, g, b;
+		uint j;
+
+		if (w == 0)
+			continue;
+
+		for (j = 0; j <= w; j++) {
+			r = (lut[i].red * (w - j) + lut[i+1].red * j) / w;
+			g = (lut[i].green * (w - j) + lut[i+1].green * j) / w;
+			b = (lut[i].blue * (w - j) + lut[i+1].blue * j) / w;
+
+			r >>= 16 - gdesc->bits;
+			g >>= 16 - gdesc->bits;
+			b >>= 16 - gdesc->bits;
+
+			table[first + j] = (r << (gdesc->bits * 2)) |
+				(g << gdesc->bits) | b;
+		}
+	}
+
+	if (dispc.is_enabled)
+		dispc_mgr_write_gamma_table(channel);
+}
+EXPORT_SYMBOL(dispc_mgr_set_gamma);
+
+static int dispc_init_gamma_tables(void)
+{
+	int channel;
+
+	if (!dispc.feat->has_gamma_table)
+		return 0;
+
+	for (channel = 0; channel < ARRAY_SIZE(dispc.gamma_table); channel++) {
+		const struct dispc_gamma_desc *gdesc = &mgr_desc[channel].gamma;
+		u32 *gt;
+
+		if (channel == OMAP_DSS_CHANNEL_LCD2 &&
+		    !dss_has_feature(FEAT_MGR_LCD2))
+			continue;
+
+		if (channel == OMAP_DSS_CHANNEL_LCD3 &&
+		    !dss_has_feature(FEAT_MGR_LCD3))
+			continue;
+
+		gt = devm_kmalloc_array(&dispc.pdev->dev, gdesc->len,
+					   sizeof(u32), GFP_KERNEL);
+		if (!gt)
+			return -ENOMEM;
+
+		dispc.gamma_table[channel] = gt;
+
+		dispc_mgr_set_gamma(channel, NULL, 0);
+	}
+	return 0;
+}
+
 static void _omap_dispc_initial_config(void)
 {
 	u32 l;
···
 		dispc.core_clk_rate = dispc_fclk_rate();
 	}
 
-	/* FUNCGATED */
-	if (dss_has_feature(FEAT_FUNCGATED))
+	/* Use gamma table mode, instead of palette mode */
+	if (dispc.feat->has_gamma_table)
+		REG_FLD_MOD(DISPC_CONFIG, 1, 3, 3);
+
+	/* For older DSS versions (FEAT_FUNCGATED) this enables
+	 * func-clock auto-gating. For newer versions
+	 * (dispc.feat->has_gamma_table) this enables tv-out gamma tables.
+	 */
+	if (dss_has_feature(FEAT_FUNCGATED) || dispc.feat->has_gamma_table)
 		REG_FLD_MOD(DISPC_CONFIG, 1, 9, 9);
 
 	dispc_setup_color_conv_coef();
···
 	.has_writeback		=	true,
 	.supports_double_pixel	=	true,
 	.reverse_ilace_field_order =	true,
+	.has_gamma_table	=	true,
 };
 
 static const struct dispc_features omap54xx_dispc_feats = {
···
 	.has_writeback		=	true,
 	.supports_double_pixel	=	true,
 	.reverse_ilace_field_order =	true,
+	.has_gamma_table	=	true,
 };
 
 static int dispc_init_features(struct platform_device *pdev)
···
 		}
 	}
 
+	r = dispc_init_gamma_tables();
+	if (r)
+		return r;
+
 	pm_runtime_enable(&pdev->dev);
 
 	r = dispc_runtime_get();
···
 		_omap_dispc_initial_config();
 
 		dispc_restore_context();
+
+		dispc_restore_gamma_tables();
 	}
 
 	dispc.is_enabled = true;

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

···
 #define DISPC_MSTANDBY_CTRL		0x0858
 #define DISPC_GLOBAL_MFLAG_ATTRIBUTE	0x085C
 
+#define DISPC_GAMMA_TABLE0		0x0630
+#define DISPC_GAMMA_TABLE1		0x0634
+#define DISPC_GAMMA_TABLE2		0x0638
+#define DISPC_GAMMA_TABLE3		0x0850
+
 /* DISPC overlay registers */
 #define DISPC_OVL_BA0(n)		(DISPC_OVL_BASE(n) + \
 					DISPC_BA0_OFFSET(n))

drivers/gpu/drm/omapdrm/dss/hdmi4.c

···
 
 	hdmi4_configure(&hdmi.core, &hdmi.wp, &hdmi.cfg);
 
-	/* bypass TV gamma table */
-	dispc_enable_gamma_table(0);
-
 	/* tv size */
 	dss_mgr_set_timings(channel, p);
 

drivers/gpu/drm/omapdrm/dss/hdmi5.c

···
 
 	hdmi5_configure(&hdmi.core, &hdmi.wp, &hdmi.cfg);
 
-	/* bypass TV gamma table */
-	dispc_enable_gamma_table(0);
-
 	/* tv size */
 	dss_mgr_set_timings(channel, p);
 

drivers/gpu/drm/omapdrm/dss/omapdss.h

···
 #include <linux/interrupt.h>
 #include <video/videomode.h>
 #include <linux/platform_data/omapdss.h>
+#include <uapi/drm/drm_mode.h>
 
 #define DISPC_IRQ_FRAMEDONE		(1 << 0)
 #define DISPC_IRQ_VSYNC			(1 << 1)
···
 		const struct omap_video_timings *timings);
 void dispc_mgr_setup(enum omap_channel channel,
 		const struct omap_overlay_manager_info *info);
+u32 dispc_mgr_gamma_size(enum omap_channel channel);
+void dispc_mgr_set_gamma(enum omap_channel channel,
+			 const struct drm_color_lut *lut,
+			 unsigned int length);
 
 int dispc_ovl_enable(enum omap_plane plane, bool enable);
 bool dispc_ovl_enabled(enum omap_plane plane);