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drm/ast: astdp: Clean up EDID reading
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Simplify ast_astdp_read_edid(). Rename register constants. Drop
unnecessary error handling. On success, the helper returns 0; an
error code otherwise.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240717143319.104012-6-tzimmermann@suse.de
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Thomas Zimmermann committed Jul 30, 2024
1 parent 2281475 commit 2000dda
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Showing 2 changed files with 44 additions and 61 deletions.
93 changes: 42 additions & 51 deletions drivers/gpu/drm/ast/ast_dp.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -17,54 +17,55 @@ bool ast_astdp_is_connected(struct ast_device *ast)
int ast_astdp_read_edid(struct drm_device *dev, u8 *ediddata)
{
struct ast_device *ast = to_ast_device(dev);
u8 i = 0, j = 0;
int ret = 0;
u8 i;

/*
* CRE5[b0]: Host reading EDID process is done
*/
if (!(ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xE5, ASTDP_HOST_EDID_READ_DONE_MASK)))
goto err_astdp_edid_not_ready;

ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0xE5, (u8) ~ASTDP_HOST_EDID_READ_DONE_MASK,
0x00);
/* Start reading EDID data */
ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0xe5, (u8)~AST_IO_VGACRE5_EDID_READ_DONE, 0x00);

for (i = 0; i < 32; i++) {
unsigned int j;

/*
* CRE4[7:0]: Read-Pointer for EDID (Unit: 4bytes); valid range: 0~64
*/
ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0xE4,
ASTDP_AND_CLEAR_MASK, (u8)i);
j = 0;
ast_set_index_reg(ast, AST_IO_VGACRI, 0xe4, i);

/*
* CRD7[b0]: valid flag for EDID
* CRD6[b0]: mirror read pointer for EDID
*/
while ((ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xD7,
ASTDP_EDID_VALID_FLAG_MASK) != 0x01) ||
(ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xD6,
ASTDP_EDID_READ_POINTER_MASK) != i)) {
for (j = 0; j < 200; ++j) {
u8 vgacrd7, vgacrd6;

/*
* Delay are getting longer with each retry.
* 1. The Delays are often 2 loops when users request "Display Settings"
*
* 1. No delay on first try
* 2. The Delays are often 2 loops when users request "Display Settings"
* of right-click of mouse.
* 2. The Delays are often longer a lot when system resume from S3/S4.
* 3. The Delays are often longer a lot when system resume from S3/S4.
*/
mdelay(j+1);

j++;
if (j > 200)
goto err_astdp_jump_out_loop_of_edid;
if (j)
mdelay(j + 1);

/* Wait for EDID offset to show up in mirror register */
vgacrd7 = ast_get_index_reg(ast, AST_IO_VGACRI, 0xd7);
if (vgacrd7 & AST_IO_VGACRD7_EDID_VALID_FLAG) {
vgacrd6 = ast_get_index_reg(ast, AST_IO_VGACRI, 0xd6);
if (vgacrd6 == i)
break;
}
}
if (j == 200) {
ret = -EBUSY;
goto out;
}

*(ediddata) = ast_get_index_reg_mask(ast, AST_IO_VGACRI,
0xD8, ASTDP_EDID_READ_DATA_MASK);
*(ediddata + 1) = ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xD9,
ASTDP_EDID_READ_DATA_MASK);
*(ediddata + 2) = ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xDA,
ASTDP_EDID_READ_DATA_MASK);
*(ediddata + 3) = ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xDB,
ASTDP_EDID_READ_DATA_MASK);
ediddata[0] = ast_get_index_reg(ast, AST_IO_VGACRI, 0xd8);
ediddata[1] = ast_get_index_reg(ast, AST_IO_VGACRI, 0xd9);
ediddata[2] = ast_get_index_reg(ast, AST_IO_VGACRI, 0xda);
ediddata[3] = ast_get_index_reg(ast, AST_IO_VGACRI, 0xdb);

if (i == 31) {
/*
Expand All @@ -76,29 +77,19 @@ int ast_astdp_read_edid(struct drm_device *dev, u8 *ediddata)
* The Bytes-126 indicates the Number of extensions to
* follow. 0 represents noextensions.
*/
*(ediddata + 3) = *(ediddata + 3) + *(ediddata + 2);
*(ediddata + 2) = 0;
ediddata[3] = ediddata[3] + ediddata[2];
ediddata[2] = 0;
}

ediddata += 4;
}

ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0xE5, (u8) ~ASTDP_HOST_EDID_READ_DONE_MASK,
ASTDP_HOST_EDID_READ_DONE);

return 0;

err_astdp_jump_out_loop_of_edid:
ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0xE5,
(u8) ~ASTDP_HOST_EDID_READ_DONE_MASK,
ASTDP_HOST_EDID_READ_DONE);
return (~(j+256) + 1);

err_astdp_edid_not_ready:
if (!(ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xE5, ASTDP_HOST_EDID_READ_DONE_MASK)))
return (~0xE5 + 1);
out:
/* Signal end of reading */
ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0xe5, (u8)~AST_IO_VGACRE5_EDID_READ_DONE,
AST_IO_VGACRE5_EDID_READ_DONE);

return 0;
return ret;
}

/*
Expand All @@ -122,9 +113,9 @@ int ast_dp_launch(struct ast_device *ast)
return -ENODEV;
}

ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0xE5,
(u8) ~ASTDP_HOST_EDID_READ_DONE_MASK,
ASTDP_HOST_EDID_READ_DONE);
ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0xe5,
(u8) ~AST_IO_VGACRE5_EDID_READ_DONE,
AST_IO_VGACRE5_EDID_READ_DONE);

return 0;
}
Expand Down
12 changes: 2 additions & 10 deletions drivers/gpu/drm/ast/ast_reg.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -38,8 +38,10 @@
#define AST_IO_VGACRCB_HWC_ENABLED BIT(1)

#define AST_IO_VGACRD1_MCU_FW_EXECUTING BIT(5)
#define AST_IO_VGACRD7_EDID_VALID_FLAG BIT(0)
#define AST_IO_VGACRDC_LINK_SUCCESS BIT(0)
#define AST_IO_VGACRDF_HPD BIT(0)
#define AST_IO_VGACRE5_EDID_READ_DONE BIT(0)

#define AST_IO_VGAIR1_R (0x5A)
#define AST_IO_VGAIR1_VREFRESH BIT(3)
Expand Down Expand Up @@ -70,12 +72,6 @@
#define AST_DP_PHY_SLEEP BIT(4)
#define AST_DP_VIDEO_ENABLE BIT(0)

/*
* CRE5[b0]: Host reading EDID process is done
*/
#define ASTDP_HOST_EDID_READ_DONE BIT(0)
#define ASTDP_HOST_EDID_READ_DONE_MASK GENMASK(0, 0)

/*
* CRDF[b4]: Mirror of AST_DP_VIDEO_ENABLE
* Precondition: A. ~AST_DP_PHY_SLEEP &&
Expand All @@ -84,10 +80,6 @@
*/
#define ASTDP_MIRROR_VIDEO_ENABLE BIT(4)

#define ASTDP_EDID_READ_POINTER_MASK GENMASK(7, 0)
#define ASTDP_EDID_VALID_FLAG_MASK GENMASK(0, 0)
#define ASTDP_EDID_READ_DATA_MASK GENMASK(7, 0)

/*
* ASTDP setmode registers:
* CRE0[7:0]: MISC0 ((0x00: 18-bpp) or (0x20: 24-bpp)
Expand Down

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