Re: [Intel-gfx] [RFC 06/19] drm/edid: clean up cea_db_is_*() functions

[Jani Nikula <jani.nikula@intel.com>]

On Wed, 23 Mar 2022, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote:
> On Tue, Mar 22, 2022 at 11:40:35PM +0200, Jani Nikula wrote:
>> Abstract helpers for matching vendor data blocks and extended tags, and
>> use them to simplify all the cea_db_is_*() functions.
>> 
>> Take void pointer as parameter to allow transitional use for both u8 *
>> and struct cea_db *.
>> 
>> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
>> ---
>>  drivers/gpu/drm/drm_edid.c | 113 ++++++++++++-------------------------
>>  1 file changed, 37 insertions(+), 76 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
>> index c12c3cbab274..a0a5a7271658 100644
>> --- a/drivers/gpu/drm/drm_edid.c
>> +++ b/drivers/gpu/drm/drm_edid.c
>> @@ -4196,12 +4196,6 @@ do_hdmi_vsdb_modes(struct drm_connector *connector, const u8 *db, u8 len,
>>  	return modes;
>>  }
>>  
>> -static int
>> -cea_db_extended_tag(const u8 *db)
>> -{
>> -	return db[1];
>> -}
>> -
>>  static int
>>  cea_revision(const u8 *cea)
>>  {
>> @@ -4313,6 +4307,22 @@ static const void *cea_db_data(const struct cea_db *db)
>>  	return db->data;
>>  }
>>  
>> +static bool cea_db_is_extended_tag(const struct cea_db *db, int tag)
>> +{
>> +	return (cea_db_tag(db) == CEA_DB_EXTENDED_TAG &&
>> +		cea_db_payload_len(db) >= 1 &&
>> +		db->data[0] == tag);
>> +}
>
> nit: not a huge fan of the redundant parens in all of these

I guess that's something I've picked up from Python, makes the
subsequent lines align nicely. Otherwise it's less pretty.

>
>> +
>> +static bool cea_db_is_vendor(const struct cea_db *db, int vendor_oui)
>
> I'd probably make the tag/oui unsigned.

Only chose int because the oui() function returns an int; maybe that
should eventually be turned into unsigned int.

>
> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
>> +{
>> +	const u8 *data = cea_db_data(db);
>> +
>> +	return (cea_db_tag(db) == CEA_DB_VENDOR &&
>> +		cea_db_payload_len(db) >= 3 &&
>> +		oui(data[2], data[1], data[0]) == vendor_oui);
>> +}
>> +
>>  static void cea_db_iter_edid_begin(const struct edid *edid, struct cea_db_iter *iter)
>>  {
>>  	memset(iter, 0, sizeof(*iter));
>> @@ -4443,79 +4453,44 @@ static void cea_db_iter_end(struct cea_db_iter *iter)
>>  	memset(iter, 0, sizeof(*iter));
>>  }
>>  
>> -static bool cea_db_is_hdmi_vsdb(const u8 *db)
>> +static bool cea_db_is_hdmi_vsdb(const void *db)
>>  {
>> -	if (cea_db_tag(db) != CEA_DB_VENDOR)
>> -		return false;
>> -
>> -	if (cea_db_payload_len(db) < 5)
>> -		return false;
>> -
>> -	return oui(db[3], db[2], db[1]) == HDMI_IEEE_OUI;
>> +	return (cea_db_is_vendor(db, HDMI_IEEE_OUI) &&
>> +		cea_db_payload_len(db) >= 5);
>>  }
>>  
>> -static bool cea_db_is_hdmi_forum_vsdb(const u8 *db)
>> +static bool cea_db_is_hdmi_forum_vsdb(const void *db)
>>  {
>> -	if (cea_db_tag(db) != CEA_DB_VENDOR)
>> -		return false;
>> -
>> -	if (cea_db_payload_len(db) < 7)
>> -		return false;
>> -
>> -	return oui(db[3], db[2], db[1]) == HDMI_FORUM_IEEE_OUI;
>> +	return (cea_db_is_vendor(db, HDMI_FORUM_IEEE_OUI) &&
>> +		cea_db_payload_len(db) >= 7);
>>  }
>>  
>> -static bool cea_db_is_microsoft_vsdb(const u8 *db)
>> +static bool cea_db_is_microsoft_vsdb(const void *db)
>>  {
>> -	if (cea_db_tag(db) != CEA_DB_VENDOR)
>> -		return false;
>> -
>> -	if (cea_db_payload_len(db) != 21)
>> -		return false;
>> -
>> -	return oui(db[3], db[2], db[1]) == MICROSOFT_IEEE_OUI;
>> +	return (cea_db_is_vendor(db, MICROSOFT_IEEE_OUI) &&
>> +		cea_db_payload_len(db) == 21);
>>  }
>>  
>> -static bool cea_db_is_vcdb(const u8 *db)
>> +static bool cea_db_is_vcdb(const void *db)
>>  {
>> -	if (cea_db_tag(db) != CEA_DB_EXTENDED_TAG)
>> -		return false;
>> -
>> -	if (cea_db_payload_len(db) != 2)
>> -		return false;
>> -
>> -	if (cea_db_extended_tag(db) != CEA_EXT_DB_VIDEO_CAP)
>> -		return false;
>> -
>> -	return true;
>> +	return (cea_db_is_extended_tag(db, CEA_EXT_DB_VIDEO_CAP) &&
>> +		cea_db_payload_len(db) == 2);
>>  }
>>  
>> -static bool cea_db_is_y420cmdb(const u8 *db)
>> +static bool cea_db_is_y420cmdb(const void *db)
>>  {
>> -	if (cea_db_tag(db) != CEA_DB_EXTENDED_TAG)
>> -		return false;
>> -
>> -	if (!cea_db_payload_len(db))
>> -		return false;
>> -
>> -	if (cea_db_extended_tag(db) != CEA_EXT_DB_420_VIDEO_CAP_MAP)
>> -		return false;
>> -
>> -	return true;
>> +	return cea_db_is_extended_tag(db, CEA_EXT_DB_420_VIDEO_CAP_MAP);
>>  }
>>  
>> -static bool cea_db_is_y420vdb(const u8 *db)
>> +static bool cea_db_is_y420vdb(const void *db)
>>  {
>> -	if (cea_db_tag(db) != CEA_DB_EXTENDED_TAG)
>> -		return false;
>> -
>> -	if (!cea_db_payload_len(db))
>> -		return false;
>> -
>> -	if (cea_db_extended_tag(db) != CEA_EXT_DB_420_VIDEO_DATA)
>> -		return false;
>> +	return cea_db_is_extended_tag(db, CEA_EXT_DB_420_VIDEO_DATA);
>> +}
>>  
>> -	return true;
>> +static bool cea_db_is_hdmi_hdr_metadata_block(const void *db)
>> +{
>> +	return (cea_db_is_extended_tag(db, CEA_EXT_DB_HDR_STATIC_METADATA) &&
>> +		cea_db_payload_len(db) >= 3);
>>  }
>>  
>>  #define for_each_cea_db(cea, i, start, end) \
>> @@ -4651,20 +4626,6 @@ static void fixup_detailed_cea_mode_clock(struct drm_display_mode *mode)
>>  	mode->clock = clock;
>>  }
>>  
>> -static bool cea_db_is_hdmi_hdr_metadata_block(const u8 *db)
>> -{
>> -	if (cea_db_tag(db) != CEA_DB_EXTENDED_TAG)
>> -		return false;
>> -
>> -	if (db[1] != CEA_EXT_DB_HDR_STATIC_METADATA)
>> -		return false;
>> -
>> -	if (cea_db_payload_len(db) < 3)
>> -		return false;
>> -
>> -	return true;
>> -}
>> -
>>  static uint8_t eotf_supported(const u8 *edid_ext)
>>  {
>>  	return edid_ext[2] &
>> -- 
>> 2.30.2

-- 
Jani Nikula, Intel Open Source Graphics Center