[PATCH 08/13] exynos: fimg2d: add g2d_set_direction

[Tobias Jakobi]

Hello Hyungwon,


Hyungwon Hwang wrote:
> On Tue, 22 Sep 2015 17:54:57 +0200
> Tobias Jakobi <tjakobi at math.uni-bielefeld.de> wrote:
> 
>> This allows setting the two direction registers, which specify how
>> the engine blits pixels. This can be used for overlapping blits,
>> which happen e.g. when 'moving' a rectangular region inside a
>> fixed buffer.
> 
> Code itself looks good. But as I know, direction registers are related
> with flip, not moving. Isn't it? I am not that much familiar with G2D.
> Please let me know if I am wrong.
that's correct, you can use the direction registers to implement
flipping operations.

However what they really do is to change the operation direction of the
G2D engine. So you can manage how the engine traverses through pixel
rows and column (either in forward or in backward direction).

Normally this doesn't matter, like it doesn't matter if you memcpy()
from one buffer to another when there is no intersection of the buffers.
However if the two buffers overlap then you have to be careful with the
direction in which you traverse the buffer.

Now if you set the x-direction of the source G2D image to forward, but
the x-direction of the destination to backward, you get your mentioned
x-flipping.

The main purpose for g2d_move() is to be used e.g. in acceleration code
for the armsoc Xorg DDX. A common operation there is not move pixel
regions around in the same buffer.


With best wishes,
Tobias


P.S.: I think the Exynos user manual mentions flipping as one example on
how to use these registers. But like I said above, it's just one way to
use it.




> 
> Best regards,
> Hyungwon Hwang
> 
>>
>> Signed-off-by: Tobias Jakobi <tjakobi at math.uni-bielefeld.de>
>> ---
>>  exynos/exynos_fimg2d.c | 13 +++++++++++++
>>  exynos/exynos_fimg2d.h | 38 ++++++++++++++++++++++++++++++++++++++
>>  2 files changed, 51 insertions(+)
>>
>> diff --git a/exynos/exynos_fimg2d.c b/exynos/exynos_fimg2d.c
>> index e997d4b..4d5419c 100644
>> --- a/exynos/exynos_fimg2d.c
>> +++ b/exynos/exynos_fimg2d.c
>> @@ -242,6 +242,19 @@ static void g2d_add_base_addr(struct g2d_context
>> *ctx, struct g2d_image *img, }
>>  
>>  /*
>> + * g2d_set_direction - setup direction register (useful for
>> overlapping blits).
>> + *
>> + * @ctx: a pointer to g2d_context structure.
>> + * @dir: a pointer to the g2d_direction_val structure.
>> + */
>> +static void g2d_set_direction(struct g2d_context *ctx,
>> +			const union g2d_direction_val *dir)
>> +{
>> +	g2d_add_cmd(ctx, SRC_MASK_DIRECT_REG, dir->val[0]);
>> +	g2d_add_cmd(ctx, DST_PAT_DIRECT_REG, dir->val[1]);
>> +}
>> +
>> +/*
>>   * g2d_reset - reset fimg2d hardware.
>>   *
>>   * @ctx: a pointer to g2d_context structure.
>> diff --git a/exynos/exynos_fimg2d.h b/exynos/exynos_fimg2d.h
>> index c6b58ac..9eee7c0 100644
>> --- a/exynos/exynos_fimg2d.h
>> +++ b/exynos/exynos_fimg2d.h
>> @@ -189,6 +189,11 @@ enum e_g2d_exec_flag {
>>  	G2D_EXEC_FLAG_ASYNC = (1 << 0)
>>  };
>>  
>> +enum e_g2d_dir_mode {
>> +	G2D_DIR_MODE_POSITIVE = 0,
>> +	G2D_DIR_MODE_NEGATIVE = 1
>> +};
>> +
>>  union g2d_point_val {
>>  	unsigned int val;
>>  	struct {
>> @@ -269,6 +274,39 @@ union g2d_blend_func_val {
>>  	} data;
>>  };
>>  
>> +union g2d_direction_val {
>> +	unsigned int val[2];
>> +	struct {
>> +		/* SRC_MSK_DIRECT_REG [0:1] (source) */
>> +		enum e_g2d_dir_mode		src_x_direction:1;
>> +		enum e_g2d_dir_mode		src_y_direction:1;
>> +
>> +		/* SRC_MSK_DIRECT_REG [2:3] */
>> +		unsigned int			reversed1:2;
>> +
>> +		/* SRC_MSK_DIRECT_REG [4:5] (mask) */
>> +		enum e_g2d_dir_mode
>> mask_x_direction:1;
>> +		enum e_g2d_dir_mode
>> mask_y_direction:1; +
>> +		/* SRC_MSK_DIRECT_REG [6:31] */
>> +		unsigned int			padding1:26;
>> +
>> +		/* DST_PAT_DIRECT_REG [0:1] (destination) */
>> +		enum e_g2d_dir_mode		dst_x_direction:1;
>> +		enum e_g2d_dir_mode		dst_y_direction:1;
>> +
>> +		/* DST_PAT_DIRECT_REG [2:3] */
>> +		unsigned int			reversed2:2;
>> +
>> +		/* DST_PAT_DIRECT_REG [4:5] (pattern) */
>> +		enum e_g2d_dir_mode		pat_x_direction:1;
>> +		enum e_g2d_dir_mode		pat_y_direction:1;
>> +
>> +		/* DST_PAT_DIRECT_REG [6:31] */
>> +		unsigned int			padding2:26;
>> +	} data;
>> +};
>> +
>>  struct g2d_image {
>>  	enum e_g2d_select_mode		select_mode;
>>  	enum e_g2d_color_mode		color_mode;
>