Re: [Intel-gfx] [RFC v1 2/6] drm/displayid: add separate drm_displayid.c

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Tue, Mar 09, 2021 at 03:54:10PM +0200, Jani Nikula wrote:
> We'll be adding more DisplayID specific functions going forward, so
> start off by splitting out a few functions to a separate file.
> 
> We don't bother with exporting the functions; at least for now they
> should be needed solely within drm.ko.
> 
> No functional changes.
> 
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

> ---
>  drivers/gpu/drm/Makefile        |  2 +-
>  drivers/gpu/drm/drm_displayid.c | 59 +++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/drm_edid.c      | 58 ++------------------------------
>  include/drm/drm_displayid.h     |  8 +++++
>  include/drm/drm_edid.h          |  3 ++
>  5 files changed, 73 insertions(+), 57 deletions(-)
>  create mode 100644 drivers/gpu/drm/drm_displayid.c
> 
> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> index 5eb5bf7c16e3..78ef2fd14f10 100644
> --- a/drivers/gpu/drm/Makefile
> +++ b/drivers/gpu/drm/Makefile
> @@ -7,7 +7,7 @@ drm-y       :=	drm_auth.o drm_cache.o \
>  		drm_file.o drm_gem.o drm_ioctl.o drm_irq.o \
>  		drm_drv.o \
>  		drm_sysfs.o drm_hashtab.o drm_mm.o \
> -		drm_crtc.o drm_fourcc.o drm_modes.o drm_edid.o \
> +		drm_crtc.o drm_fourcc.o drm_modes.o drm_edid.o drm_displayid.o \
>  		drm_encoder_slave.o \
>  		drm_trace_points.o drm_prime.o \
>  		drm_rect.o drm_vma_manager.o drm_flip_work.o \
> diff --git a/drivers/gpu/drm/drm_displayid.c b/drivers/gpu/drm/drm_displayid.c
> new file mode 100644
> index 000000000000..908bbe6feb61
> --- /dev/null
> +++ b/drivers/gpu/drm/drm_displayid.c
> @@ -0,0 +1,59 @@
> +// SPDX-License-Identifier: MIT
> +/*
> + * Copyright © 2021 Intel Corporation
> + */
> +
> +#include <drm/drm_displayid.h>
> +#include <drm/drm_edid.h>
> +#include <drm/drm_print.h>
> +
> +static int validate_displayid(const u8 *displayid, int length, int idx)
> +{
> +	int i, dispid_length;
> +	u8 csum = 0;
> +	const struct displayid_hdr *base;
> +
> +	base = (const struct displayid_hdr *)&displayid[idx];
> +
> +	DRM_DEBUG_KMS("base revision 0x%x, length %d, %d %d\n",
> +		      base->rev, base->bytes, base->prod_id, base->ext_count);
> +
> +	/* +1 for DispID checksum */
> +	dispid_length = sizeof(*base) + base->bytes + 1;
> +	if (dispid_length > length - idx)
> +		return -EINVAL;
> +
> +	for (i = 0; i < dispid_length; i++)
> +		csum += displayid[idx + i];
> +	if (csum) {
> +		DRM_NOTE("DisplayID checksum invalid, remainder is %d\n", csum);
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +const u8 *drm_find_displayid_extension(const struct edid *edid,
> +				       int *length, int *idx,
> +				       int *ext_index)
> +{
> +	const u8 *displayid = drm_find_edid_extension(edid, DISPLAYID_EXT, ext_index);
> +	const struct displayid_hdr *base;
> +	int ret;
> +
> +	if (!displayid)
> +		return NULL;
> +
> +	/* EDID extensions block checksum isn't for us */
> +	*length = EDID_LENGTH - 1;
> +	*idx = 1;
> +
> +	ret = validate_displayid(displayid, *length, *idx);
> +	if (ret)
> +		return NULL;
> +
> +	base = (const struct displayid_hdr *)&displayid[*idx];
> +	*length = *idx + sizeof(*base) + base->bytes;
> +
> +	return displayid;
> +}
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index d510b827a1f8..58e61f792bc7 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -1585,8 +1585,6 @@ module_param_named(edid_fixup, edid_fixup, int, 0400);
>  MODULE_PARM_DESC(edid_fixup,
>  		 "Minimum number of valid EDID header bytes (0-8, default 6)");
>  
> -static int validate_displayid(const u8 *displayid, int length, int idx);
> -
>  static int drm_edid_block_checksum(const u8 *raw_edid)
>  {
>  	int i;
> @@ -3241,8 +3239,8 @@ add_detailed_modes(struct drm_connector *connector, struct edid *edid,
>  /*
>   * Search EDID for CEA extension block.
>   */
> -static const u8 *drm_find_edid_extension(const struct edid *edid,
> -					 int ext_id, int *ext_index)
> +const u8 *drm_find_edid_extension(const struct edid *edid,
> +				  int ext_id, int *ext_index)
>  {
>  	const u8 *edid_ext = NULL;
>  	int i;
> @@ -3266,32 +3264,6 @@ static const u8 *drm_find_edid_extension(const struct edid *edid,
>  	return edid_ext;
>  }
>  
> -
> -static const u8 *drm_find_displayid_extension(const struct edid *edid,
> -					      int *length, int *idx,
> -					      int *ext_index)
> -{
> -	const u8 *displayid = drm_find_edid_extension(edid, DISPLAYID_EXT, ext_index);
> -	const struct displayid_hdr *base;
> -	int ret;
> -
> -	if (!displayid)
> -		return NULL;
> -
> -	/* EDID extensions block checksum isn't for us */
> -	*length = EDID_LENGTH - 1;
> -	*idx = 1;
> -
> -	ret = validate_displayid(displayid, *length, *idx);
> -	if (ret)
> -		return NULL;
> -
> -	base = (const struct displayid_hdr *)&displayid[*idx];
> -	*length = *idx + sizeof(*base) + base->bytes;
> -
> -	return displayid;
> -}
> -
>  static const u8 *drm_find_cea_extension(const struct edid *edid)
>  {
>  	int length, idx;
> @@ -5287,32 +5259,6 @@ u32 drm_add_display_info(struct drm_connector *connector, const struct edid *edi
>  	return quirks;
>  }
>  
> -static int validate_displayid(const u8 *displayid, int length, int idx)
> -{
> -	int i, dispid_length;
> -	u8 csum = 0;
> -	const struct displayid_hdr *base;
> -
> -	base = (const struct displayid_hdr *)&displayid[idx];
> -
> -	DRM_DEBUG_KMS("base revision 0x%x, length %d, %d %d\n",
> -		      base->rev, base->bytes, base->prod_id, base->ext_count);
> -
> -	/* +1 for DispID checksum */
> -	dispid_length = sizeof(*base) + base->bytes + 1;
> -	if (dispid_length > length - idx)
> -		return -EINVAL;
> -
> -	for (i = 0; i < dispid_length; i++)
> -		csum += displayid[idx + i];
> -	if (csum) {
> -		DRM_NOTE("DisplayID checksum invalid, remainder is %d\n", csum);
> -		return -EINVAL;
> -	}
> -
> -	return 0;
> -}
> -
>  static struct drm_display_mode *drm_mode_displayid_detailed(struct drm_device *dev,
>  							    struct displayid_detailed_timings_1 *timings)
>  {
> diff --git a/include/drm/drm_displayid.h b/include/drm/drm_displayid.h
> index f141c0eff083..3c6db22a518a 100644
> --- a/include/drm/drm_displayid.h
> +++ b/include/drm/drm_displayid.h
> @@ -22,6 +22,10 @@
>  #ifndef DRM_DISPLAYID_H
>  #define DRM_DISPLAYID_H
>  
> +#include <linux/types.h>
> +
> +struct edid;
> +
>  #define DATA_BLOCK_PRODUCT_ID 0x00
>  #define DATA_BLOCK_DISPLAY_PARAMETERS 0x01
>  #define DATA_BLOCK_COLOR_CHARACTERISTICS 0x02
> @@ -100,4 +104,8 @@ struct displayid_detailed_timing_block {
>  	     (idx) += sizeof(struct displayid_block) + (block)->num_bytes, \
>  	     (block) = (const struct displayid_block *)&(displayid)[idx])
>  
> +const u8 *drm_find_displayid_extension(const struct edid *edid,
> +				       int *length, int *idx,
> +				       int *ext_index);
> +
>  #endif
> diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
> index a158f585f658..759328a5eeb2 100644
> --- a/include/drm/drm_edid.h
> +++ b/include/drm/drm_edid.h
> @@ -543,5 +543,8 @@ struct drm_display_mode *drm_mode_find_dmt(struct drm_device *dev,
>  struct drm_display_mode *
>  drm_display_mode_from_cea_vic(struct drm_device *dev,
>  			      u8 video_code);
> +const u8 *drm_find_edid_extension(const struct edid *edid,
> +				  int ext_id, int *ext_index);
> +
>  
>  #endif /* __DRM_EDID_H__ */
> -- 
> 2.20.1
> 
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-- 
Ville Syrjälä
Intel
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