Re: [PATCH 2/6] drm: Add drm_simple_encoder_{init,create}()

[Thomas Zimmermann <tzimmermann@suse.de>]

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Hi

Am 07.02.20 um 14:37 schrieb Daniel Vetter:
> On Fri, Feb 07, 2020 at 09:41:31AM +0100, Thomas Zimmermann wrote:
>> The simple-encoder helpers initialize an encoder with an empty
>> implementation. This covers the requirements of most of the existing
>> DRM drivers. A call to drm_simple_encoder_create() allocates and
>> initializes an encoder instance, a call to drm_simple_encoder_init()
>> initializes a pre-allocated instance.
>>
>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> 
> This has quick a bit midlayer taste to it ... I think having this as a
> helper would be cleaner ...

How would such a helper roughly look like?

Best regards
Thomas

> 
> The other bit is drm_encoder->possible_crtcs. If we do create a helper for
> these, lets at least try to make them not suck too badly :-) Otherwise I
> guess it would be time to officially document what exactly possible_crtcs
> == 0 means from an uabi pov.
> -Daniel
> 
>> ---
>>  drivers/gpu/drm/drm_encoder.c | 116 ++++++++++++++++++++++++++++++++++
>>  include/drm/drm_encoder.h     |  10 +++
>>  2 files changed, 126 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/drm_encoder.c b/drivers/gpu/drm/drm_encoder.c
>> index ffe691a1bf34..1a65cab1f310 100644
>> --- a/drivers/gpu/drm/drm_encoder.c
>> +++ b/drivers/gpu/drm/drm_encoder.c
>> @@ -178,6 +178,122 @@ int drm_encoder_init(struct drm_device *dev,
>>  }
>>  EXPORT_SYMBOL(drm_encoder_init);
>>  
>> +static const struct drm_encoder_funcs drm_simple_encoder_funcs_cleanup = {
>> +	.destroy = drm_encoder_cleanup,
>> +};
>> +
>> +/**
>> + * drm_simple_encoder_init - Init a preallocated encoder
>> + * @dev: drm device
>> + * @funcs: callbacks for this encoder
>> + * @encoder_type: user visible type of the encoder
>> + * @name: printf style format string for the encoder name, or NULL
>> + *        for default name
>> + *
>> + * Initialises a preallocated encoder that has no further functionality. The
>> + * encoder will be released automatically.
>> + *
>> + * Returns:
>> + * Zero on success, error code on failure.
>> + */
>> +int drm_simple_encoder_init(struct drm_device *dev,
>> +			    struct drm_encoder *encoder,
>> +			    int encoder_type, const char *name, ...)
>> +{
>> +	char *namestr = NULL;
>> +	int ret;
>> +
>> +	if (name) {
>> +		va_list ap;
>> +
>> +		va_start(ap, name);
>> +		namestr = kvasprintf(GFP_KERNEL, name, ap);
>> +		va_end(ap);
>> +		if (!namestr)
>> +			return -ENOMEM;
>> +	}
>> +
>> +	ret = __drm_encoder_init(dev, encoder,
>> +				 &drm_simple_encoder_funcs_cleanup,
>> +				 encoder_type, namestr);
>> +	if (ret)
>> +		goto err_kfree;
>> +
>> +	return 0;
>> +
>> +err_kfree:
>> +	if (name)
>> +		kfree(namestr);
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL(drm_simple_encoder_init);
>> +
>> +static void drm_encoder_destroy(struct drm_encoder *encoder)
>> +{
>> +	struct drm_device *dev = encoder->dev;
>> +
>> +	drm_encoder_cleanup(encoder);
>> +	devm_kfree(dev->dev, encoder);
>> +}
>> +
>> +static const struct drm_encoder_funcs drm_simple_encoder_funcs_destroy = {
>> +	.destroy = drm_encoder_destroy,
>> +};
>> +
>> +/**
>> + * drm_simple_encoder_create - Allocate and initialize an encoder
>> + * @dev: drm device
>> + * @encoder_type: user visible type of the encoder
>> + * @name: printf style format string for the encoder name, or NULL for
>> + *        default name
>> + *
>> + * Allocates and initialises an encoder that has no further functionality. The
>> + * encoder will be released automatically.
>> + *
>> + * Returns:
>> + * The encoder on success, a pointer-encoder error code on failure.
>> + */
>> +struct drm_encoder *drm_simple_encoder_create(struct drm_device *dev,
>> +					      int encoder_type,
>> +					      const char *name, ...)
>> +{
>> +	char *namestr = NULL;
>> +	struct drm_encoder *encoder;
>> +	int ret;
>> +
>> +	encoder = devm_kzalloc(dev->dev, sizeof(*encoder), GFP_KERNEL);
>> +	if (!encoder)
>> +		return ERR_PTR(-ENOMEM);
>> +
>> +	if (name) {
>> +		va_list ap;
>> +
>> +		va_start(ap, name);
>> +		namestr = kvasprintf(GFP_KERNEL, name, ap);
>> +		va_end(ap);
>> +		if (!namestr) {
>> +			ret = -ENOMEM;
>> +			goto err_devm_kfree;
>> +		}
>> +	}
>> +
>> +	ret = __drm_encoder_init(dev, encoder,
>> +				 &drm_simple_encoder_funcs_destroy,
>> +				 encoder_type, namestr);
>> +	if (ret)
>> +		goto err_kfree;
>> +
>> +	return encoder;
>> +
>> +err_kfree:
>> +	if (name)
>> +		kfree(namestr);
>> +err_devm_kfree:
>> +	devm_kfree(dev->dev, encoder);
>> +	return ERR_PTR(ret);
>> +}
>> +EXPORT_SYMBOL(drm_simple_encoder_create);
>> +
>>  /**
>>   * drm_encoder_cleanup - cleans up an initialised encoder
>>   * @encoder: encoder to cleanup
>> diff --git a/include/drm/drm_encoder.h b/include/drm/drm_encoder.h
>> index 5623994b6e9e..0214f6cf9de6 100644
>> --- a/include/drm/drm_encoder.h
>> +++ b/include/drm/drm_encoder.h
>> @@ -190,6 +190,16 @@ int drm_encoder_init(struct drm_device *dev,
>>  		     const struct drm_encoder_funcs *funcs,
>>  		     int encoder_type, const char *name, ...);
>>  
>> +__printf(4, 5)
>> +int drm_simple_encoder_init(struct drm_device *dev,
>> +			    struct drm_encoder *encoder,
>> +			    int encoder_type, const char *name, ...);
>> +
>> +__printf(3, 4)
>> +struct drm_encoder *drm_simple_encoder_create(struct drm_device *dev,
>> +					      int encoder_type,
>> +					      const char *name, ...);
>> +
>>  /**
>>   * drm_encoder_index - find the index of a registered encoder
>>   * @encoder: encoder to find index for
>> -- 
>> 2.25.0
>>
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer


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