[PATCH 1/2] OMAPDSS: Features: Maintain dss_feats as a list

The number of dss_feat_id members has increased to a large value, the current
way of assigning a subset of these features (for a particular OMAP) as a mask
is no longer feasible.

Maintain the subset of features supported as lists. Make the function
dss_has_feature() traverse through this list.

Signed-off-by: Archit Taneja <redacted>
---
 drivers/video/omap2/dss/dss_features.c |  140 +++++++++++++++++++++++---------
 drivers/video/omap2/dss/dss_features.h |   54 ++++++------
 2 files changed, 128 insertions(+), 66 deletions(-)

diff --git a/drivers/video/omap2/dss/dss_features.c b/drivers/video/omap2/dss/dss_features.c
index 419419a..656cb69 100644
--- a/drivers/video/omap2/dss/dss_features.c
+++ b/drivers/video/omap2/dss/dss_features.c

@@ -41,7 +41,8 @@ struct omap_dss_features {
 	const struct dss_reg_field *reg_fields;
 	const int num_reg_fields;
 
-	const u32 has_feature;
+	const enum dss_feat_id *features;
+	const int num_features;
 
 	const int num_mgrs;
 	const int num_ovls;

@@ -337,15 +338,92 @@ static const struct dss_param_range omap4_dss_param_range[] = {
 	[FEAT_PARAM_LINEWIDTH]			= { 1, 2048 },
 };
 
+static const enum dss_feat_id omap2_dss_feat_list[] = {
+	FEAT_LCDENABLEPOL,
+	FEAT_LCDENABLESIGNAL,
+	FEAT_PCKFREEENABLE,
+	FEAT_FUNCGATED,
+	FEAT_ROWREPEATENABLE,
+	FEAT_RESIZECONF,
+};
+
+static const enum dss_feat_id omap3430_dss_feat_list[] = {
+	FEAT_LCDENABLEPOL,
+	FEAT_LCDENABLESIGNAL,
+	FEAT_PCKFREEENABLE,
+	FEAT_FUNCGATED,
+	FEAT_LINEBUFFERSPLIT,
+	FEAT_ROWREPEATENABLE,
+	FEAT_RESIZECONF,
+	FEAT_DSI_PLL_FREQSEL,
+	FEAT_DSI_REVERSE_TXCLKESC,
+	FEAT_VENC_REQUIRES_TV_DAC_CLK,
+	FEAT_CPR,
+	FEAT_PRELOAD,
+	FEAT_FIR_COEF_V,
+	FEAT_ALPHA_FIXED_ZORDER,
+	FEAT_FIFO_MERGE,
+	FEAT_OMAP3_DSI_FIFO_BUG,
+};
+
+static const enum dss_feat_id omap3630_dss_feat_list[] = {
+	FEAT_LCDENABLEPOL,
+	FEAT_LCDENABLESIGNAL,
+	FEAT_PCKFREEENABLE,
+	FEAT_FUNCGATED,
+	FEAT_LINEBUFFERSPLIT,
+	FEAT_ROWREPEATENABLE,
+	FEAT_RESIZECONF,
+	FEAT_DSI_PLL_PWR_BUG,
+	FEAT_DSI_PLL_FREQSEL,
+	FEAT_CPR,
+	FEAT_PRELOAD,
+	FEAT_FIR_COEF_V,
+	FEAT_ALPHA_FIXED_ZORDER,
+	FEAT_FIFO_MERGE,
+	FEAT_OMAP3_DSI_FIFO_BUG,
+};
+
+static const enum dss_feat_id omap4430_es1_0_dss_feat_list[] = {
+	FEAT_MGR_LCD2,
+	FEAT_CORE_CLK_DIV,
+	FEAT_LCD_CLK_SRC,
+	FEAT_DSI_DCS_CMD_CONFIG_VC,
+	FEAT_DSI_VC_OCP_WIDTH,
+	FEAT_DSI_GNQ,
+	FEAT_HANDLE_UV_SEPARATE,
+	FEAT_ATTR2,
+	FEAT_CPR,
+	FEAT_PRELOAD,
+	FEAT_FIR_COEF_V,
+	FEAT_ALPHA_FREE_ZORDER,
+	FEAT_FIFO_MERGE,
+};
+
+static const enum dss_feat_id omap4_dss_feat_list[] = {
+	FEAT_MGR_LCD2,
+	FEAT_CORE_CLK_DIV,
+	FEAT_LCD_CLK_SRC,
+	FEAT_DSI_DCS_CMD_CONFIG_VC,
+	FEAT_DSI_VC_OCP_WIDTH,
+	FEAT_DSI_GNQ,
+	FEAT_HDMI_CTS_SWMODE,
+	FEAT_HANDLE_UV_SEPARATE,
+	FEAT_ATTR2,
+	FEAT_CPR,
+	FEAT_PRELOAD,
+	FEAT_FIR_COEF_V,
+	FEAT_ALPHA_FREE_ZORDER,
+	FEAT_FIFO_MERGE,
+};
+
 /* OMAP2 DSS Features */
 static const struct omap_dss_features omap2_dss_features = {
 	.reg_fields = omap2_dss_reg_fields,
 	.num_reg_fields = ARRAY_SIZE(omap2_dss_reg_fields),
 
-	.has_feature	-		FEAT_LCDENABLEPOL | FEAT_LCDENABLESIGNAL |
-		FEAT_PCKFREEENABLE | FEAT_FUNCGATED |
-		FEAT_ROWREPEATENABLE | FEAT_RESIZECONF,
+	.features = omap2_dss_feat_list,
+	.num_features = ARRAY_SIZE(omap2_dss_feat_list),
 
 	.num_mgrs = 2,
 	.num_ovls = 3,

@@ -363,15 +441,8 @@ static const struct omap_dss_features omap3430_dss_features = {
 	.reg_fields = omap3_dss_reg_fields,
 	.num_reg_fields = ARRAY_SIZE(omap3_dss_reg_fields),
 
-	.has_feature	-		FEAT_LCDENABLEPOL |
-		FEAT_LCDENABLESIGNAL | FEAT_PCKFREEENABLE |
-		FEAT_FUNCGATED | FEAT_ROWREPEATENABLE |
-		FEAT_LINEBUFFERSPLIT | FEAT_RESIZECONF |
-		FEAT_DSI_PLL_FREQSEL | FEAT_DSI_REVERSE_TXCLKESC |
-		FEAT_VENC_REQUIRES_TV_DAC_CLK | FEAT_CPR | FEAT_PRELOAD |
-		FEAT_FIR_COEF_V | FEAT_ALPHA_FIXED_ZORDER | FEAT_FIFO_MERGE |
-		FEAT_OMAP3_DSI_FIFO_BUG,
+	.features = omap3430_dss_feat_list,
+	.num_features = ARRAY_SIZE(omap3430_dss_feat_list),
 
 	.num_mgrs = 2,
 	.num_ovls = 3,

@@ -388,15 +459,8 @@ static const struct omap_dss_features omap3630_dss_features = {
 	.reg_fields = omap3_dss_reg_fields,
 	.num_reg_fields = ARRAY_SIZE(omap3_dss_reg_fields),
 
-	.has_feature    -		FEAT_LCDENABLEPOL |
-		FEAT_LCDENABLESIGNAL | FEAT_PCKFREEENABLE |
-		FEAT_FUNCGATED |
-		FEAT_ROWREPEATENABLE | FEAT_LINEBUFFERSPLIT |
-		FEAT_RESIZECONF | FEAT_DSI_PLL_PWR_BUG |
-		FEAT_DSI_PLL_FREQSEL | FEAT_CPR | FEAT_PRELOAD |
-		FEAT_FIR_COEF_V | FEAT_ALPHA_FIXED_ZORDER | FEAT_FIFO_MERGE |
-		FEAT_OMAP3_DSI_FIFO_BUG,
+	.features = omap3630_dss_feat_list,
+	.num_features = ARRAY_SIZE(omap3630_dss_feat_list),
 
 	.num_mgrs = 2,
 	.num_ovls = 3,

@@ -415,13 +479,8 @@ static const struct omap_dss_features omap4430_es1_0_dss_features  = {
 	.reg_fields = omap4_dss_reg_fields,
 	.num_reg_fields = ARRAY_SIZE(omap4_dss_reg_fields),
 
-	.has_feature	-		FEAT_MGR_LCD2 |
-		FEAT_CORE_CLK_DIV | FEAT_LCD_CLK_SRC |
-		FEAT_DSI_DCS_CMD_CONFIG_VC | FEAT_DSI_VC_OCP_WIDTH |
-		FEAT_DSI_GNQ | FEAT_HANDLE_UV_SEPARATE | FEAT_ATTR2 |
-		FEAT_CPR | FEAT_PRELOAD | FEAT_FIR_COEF_V |
-		FEAT_ALPHA_FREE_ZORDER | FEAT_FIFO_MERGE,
+	.features = omap4430_es1_0_dss_feat_list,
+	.num_features = ARRAY_SIZE(omap4430_es1_0_dss_feat_list),
 
 	.num_mgrs = 3,
 	.num_ovls = 4,

@@ -439,14 +498,8 @@ static const struct omap_dss_features omap4_dss_features = {
 	.reg_fields = omap4_dss_reg_fields,
 	.num_reg_fields = ARRAY_SIZE(omap4_dss_reg_fields),
 
-	.has_feature	-		FEAT_MGR_LCD2 |
-		FEAT_CORE_CLK_DIV | FEAT_LCD_CLK_SRC |
-		FEAT_DSI_DCS_CMD_CONFIG_VC | FEAT_DSI_VC_OCP_WIDTH |
-		FEAT_DSI_GNQ | FEAT_HDMI_CTS_SWMODE |
-		FEAT_HANDLE_UV_SEPARATE | FEAT_ATTR2 | FEAT_CPR |
-		FEAT_PRELOAD | FEAT_FIR_COEF_V | FEAT_ALPHA_FREE_ZORDER |
-		FEAT_FIFO_MERGE,
+	.features = omap4_dss_feat_list,
+	.num_features = ARRAY_SIZE(omap4_dss_feat_list),
 
 	.num_mgrs = 3,
 	.num_ovls = 4,

@@ -550,7 +603,16 @@ u32 dss_feat_get_burst_size_unit(void)
 /* DSS has_feature check */
 bool dss_has_feature(enum dss_feat_id id)
 {
-	return omap_current_dss_features->has_feature & id;
+	int i;
+	const enum dss_feat_id *features = omap_current_dss_features->features;
+	const int num_features = omap_current_dss_features->num_features;
+
+	for (i = 0; i < num_features; i++) {
+		if (features[i] = id)
+			return true;
+	}
+
+	return false;
 }
 
 void dss_feat_get_reg_field(enum dss_feat_reg_field id, u8 *start, u8 *end)

diff --git a/drivers/video/omap2/dss/dss_features.h b/drivers/video/omap2/dss/dss_features.h
index 5f9b821..682f091 100644
--- a/drivers/video/omap2/dss/dss_features.h
+++ b/drivers/video/omap2/dss/dss_features.h

@@ -31,36 +31,36 @@
 
 /* DSS has feature id */
 enum dss_feat_id {
-	FEAT_LCDENABLEPOL		= 1 << 3,
-	FEAT_LCDENABLESIGNAL		= 1 << 4,
-	FEAT_PCKFREEENABLE		= 1 << 5,
-	FEAT_FUNCGATED			= 1 << 6,
-	FEAT_MGR_LCD2			= 1 << 7,
-	FEAT_LINEBUFFERSPLIT		= 1 << 8,
-	FEAT_ROWREPEATENABLE		= 1 << 9,
-	FEAT_RESIZECONF			= 1 << 10,
+	FEAT_LCDENABLEPOL,
+	FEAT_LCDENABLESIGNAL,
+	FEAT_PCKFREEENABLE,
+	FEAT_FUNCGATED,
+	FEAT_MGR_LCD2,
+	FEAT_LINEBUFFERSPLIT,
+	FEAT_ROWREPEATENABLE,
+	FEAT_RESIZECONF,
 	/* Independent core clk divider */
-	FEAT_CORE_CLK_DIV		= 1 << 11,
-	FEAT_LCD_CLK_SRC		= 1 << 12,
+	FEAT_CORE_CLK_DIV,
+	FEAT_LCD_CLK_SRC,
 	/* DSI-PLL power command 0x3 is not working */
-	FEAT_DSI_PLL_PWR_BUG		= 1 << 13,
-	FEAT_DSI_PLL_FREQSEL		= 1 << 14,
-	FEAT_DSI_DCS_CMD_CONFIG_VC	= 1 << 15,
-	FEAT_DSI_VC_OCP_WIDTH		= 1 << 16,
-	FEAT_DSI_REVERSE_TXCLKESC	= 1 << 17,
-	FEAT_DSI_GNQ			= 1 << 18,
-	FEAT_HDMI_CTS_SWMODE		= 1 << 19,
-	FEAT_HANDLE_UV_SEPARATE         = 1 << 20,
-	FEAT_ATTR2                      = 1 << 21,
-	FEAT_VENC_REQUIRES_TV_DAC_CLK	= 1 << 22,
-	FEAT_CPR			= 1 << 23,
-	FEAT_PRELOAD			= 1 << 24,
-	FEAT_FIR_COEF_V			= 1 << 25,
-	FEAT_ALPHA_FIXED_ZORDER		= 1 << 26,
-	FEAT_ALPHA_FREE_ZORDER		= 1 << 27,
-	FEAT_FIFO_MERGE			= 1 << 28,
+	FEAT_DSI_PLL_PWR_BUG,
+	FEAT_DSI_PLL_FREQSEL,
+	FEAT_DSI_DCS_CMD_CONFIG_VC,
+	FEAT_DSI_VC_OCP_WIDTH,
+	FEAT_DSI_REVERSE_TXCLKESC,
+	FEAT_DSI_GNQ,
+	FEAT_HDMI_CTS_SWMODE,
+	FEAT_HANDLE_UV_SEPARATE,
+	FEAT_ATTR2,
+	FEAT_VENC_REQUIRES_TV_DAC_CLK,
+	FEAT_CPR,
+	FEAT_PRELOAD,
+	FEAT_FIR_COEF_V,
+	FEAT_ALPHA_FIXED_ZORDER,
+	FEAT_ALPHA_FREE_ZORDER,
+	FEAT_FIFO_MERGE,
 	/* An unknown HW bug causing the normal FIFO thresholds not to work */
-	FEAT_OMAP3_DSI_FIFO_BUG		= 1 << 29,
+	FEAT_OMAP3_DSI_FIFO_BUG,
 };
 
 /* DSS register field id */

-- 
1.7.4.1

Hi,

On Mon, 2012-01-30 at 10:52 +0530, Archit Taneja wrote:

The number of dss_feat_id members has increased to a large value, the current
way of assigning a subset of these features (for a particular OMAP) as a mask
is no longer feasible.

Maintain the subset of features supported as lists. Make the function
dss_has_feature() traverse through this list.

I think this makes the code easier to maintain, so in that sense it is
good. But I do hesitate a bit, I think many features are checked in
often used code paths (the configuration done on each frame when
swapping/panning), and bit compare versus finding an item in a list
could have performance impact.

Then again, I'm purely guessing here, as it could well be that compared
to the other code, checking the features is insignificant. Thus, I'm
fine with this patch, and we can optimize it later if need be.

However, I'm anyway giving a few ideas how this could also be handled:

- 64 bit mask. Would be simple, but we'd still have a hard limit there.

- Variable length bitmask, i.e. an int or byte array from which a
particular bit is checked. There could be a ready made datatype for this
in the kernel.

- Lists like in this patch, but in sorted order. Then, if we're looking
for a feat which has, say, number 4 assigned to it, we can stop
iterating the list when we hit a feat > 4 in the list. Quite simple
optimization, but needs extra maintenance to keep the feat lists sorted.

 Tomi

On Mon, 2012-02-06 at 16:54 +0530, Archit Taneja wrote:

On Monday 06 February 2012 04:12 PM, Tomi Valkeinen wrote:

quoted

Hi,

On Mon, 2012-01-30 at 10:52 +0530, Archit Taneja wrote:

quoted

The number of dss_feat_id members has increased to a large value, the current
way of assigning a subset of these features (for a particular OMAP) as a mask
is no longer feasible.

Maintain the subset of features supported as lists. Make the function
dss_has_feature() traverse through this list.

I think this makes the code easier to maintain, so in that sense it is
good. But I do hesitate a bit, I think many features are checked in
often used code paths (the configuration done on each frame when
swapping/panning), and bit compare versus finding an item in a list
could have performance impact.

Then again, I'm purely guessing here, as it could well be that compared
to the other code, checking the features is insignificant. Thus, I'm
fine with this patch, and we can optimize it later if need be.

However, I'm anyway giving a few ideas how this could also be handled:

- 64 bit mask. Would be simple, but we'd still have a hard limit there.

- Variable length bitmask, i.e. an int or byte array from which a
particular bit is checked. There could be a ready made datatype for this
in the kernel.

There seems to be a bitmask library:

tools/power/cpupower/utils/helpers/bitmask.c

I don't know how easy it would be to access this though.

quoted

- Lists like in this patch, but in sorted order. Then, if we're looking
for a feat which has, say, number 4 assigned to it, we can stop
iterating the list when we hit a feat>  4 in the list. Quite simple
optimization, but needs extra maintenance to keep the feat lists sorted.

This sounds fine. It shouldn't be too much of an effort to maintain 
sorted lists. We'll just need to ensure that a new feature added has the 
largest integer value, and is always added at the end of the list(s).

Not necessarily. As we always search the list from index 0 forward, the
most often needed features could be in the beginning of the list so they
are found faster. At least some features are clearly needed only in some
enable/disable paths or similar, and they could clearly be low priority.

 Tomi

On Monday 06 February 2012 04:12 PM, Tomi Valkeinen wrote:

Hi,

On Mon, 2012-01-30 at 10:52 +0530, Archit Taneja wrote:

quoted

The number of dss_feat_id members has increased to a large value, the current
way of assigning a subset of these features (for a particular OMAP) as a mask
is no longer feasible.

Maintain the subset of features supported as lists. Make the function
dss_has_feature() traverse through this list.

I think this makes the code easier to maintain, so in that sense it is
good. But I do hesitate a bit, I think many features are checked in
often used code paths (the configuration done on each frame when
swapping/panning), and bit compare versus finding an item in a list
could have performance impact.

Then again, I'm purely guessing here, as it could well be that compared
to the other code, checking the features is insignificant. Thus, I'm
fine with this patch, and we can optimize it later if need be.

However, I'm anyway giving a few ideas how this could also be handled:

- 64 bit mask. Would be simple, but we'd still have a hard limit there.

- Variable length bitmask, i.e. an int or byte array from which a
particular bit is checked. There could be a ready made datatype for this
in the kernel.

There seems to be a bitmask library:

tools/power/cpupower/utils/helpers/bitmask.c

I don't know how easy it would be to access this though.

- Lists like in this patch, but in sorted order. Then, if we're looking
for a feat which has, say, number 4 assigned to it, we can stop
iterating the list when we hit a feat>  4 in the list. Quite simple
optimization, but needs extra maintenance to keep the feat lists sorted.

This sounds fine. It shouldn't be too much of an effort to maintain 
sorted lists. We'll just need to ensure that a new feature added has the 
largest integer value, and is always added at the end of the list(s).

Archit

  Tomi

On Monday 06 February 2012 04:58 PM, Tomi Valkeinen wrote:

On Mon, 2012-02-06 at 16:54 +0530, Archit Taneja wrote:

quoted

On Monday 06 February 2012 04:12 PM, Tomi Valkeinen wrote:

quoted

Hi,

On Mon, 2012-01-30 at 10:52 +0530, Archit Taneja wrote:

quoted

The number of dss_feat_id members has increased to a large value, the current
way of assigning a subset of these features (for a particular OMAP) as a mask
is no longer feasible.

Maintain the subset of features supported as lists. Make the function
dss_has_feature() traverse through this list.

I think this makes the code easier to maintain, so in that sense it is
good. But I do hesitate a bit, I think many features are checked in
often used code paths (the configuration done on each frame when
swapping/panning), and bit compare versus finding an item in a list
could have performance impact.

Then again, I'm purely guessing here, as it could well be that compared
to the other code, checking the features is insignificant. Thus, I'm
fine with this patch, and we can optimize it later if need be.

However, I'm anyway giving a few ideas how this could also be handled:

- 64 bit mask. Would be simple, but we'd still have a hard limit there.

- Variable length bitmask, i.e. an int or byte array from which a
particular bit is checked. There could be a ready made datatype for this
in the kernel.

There seems to be a bitmask library:

tools/power/cpupower/utils/helpers/bitmask.c

I don't know how easy it would be to access this though.

quoted

- Lists like in this patch, but in sorted order. Then, if we're looking
for a feat which has, say, number 4 assigned to it, we can stop
iterating the list when we hit a feat>   4 in the list. Quite simple
optimization, but needs extra maintenance to keep the feat lists sorted.

This sounds fine. It shouldn't be too much of an effort to maintain
sorted lists. We'll just need to ensure that a new feature added has the
largest integer value, and is always added at the end of the list(s).

Not necessarily. As we always search the list from index 0 forward, the
most often needed features could be in the beginning of the list so they
are found faster. At least some features are clearly needed only in some
enable/disable paths or similar, and they could clearly be low priority.

Right, it would be harder to maintain sorted lists in this case, and it 
wouldn't be always straight forward to decide which feature has more 
priority over other :)

Archit

  Tomi