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Subject: Re: [RFC PATCH v2] media: cec: DRM connector to CEC dev mapping
To:     Dariusz Marcinkiewicz <darekm@google.com>,
        linux-media@vger.kernel.org, hans.verkuil@cisco.com
Cc:     linux-kernel@vger.kernel.org
References: <c1b7d461-d0b1-e3a4-f8fd-7c757a5e38f6@xs4all.nl>
 <20190409073342.74052-1-darekm@google.com>
From:   Hans Verkuil <hverkuil@xs4all.nl>
Message-ID: <e49fc5a4-1e15-2070-7c70-7ab8f19777a4@xs4all.nl>
Date:   Thu, 11 Apr 2019 15:37:48 +0200
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Hi Dariusz,

This is much closer to what I am looking for, but it can be simplified a bit more:

On 4/9/19 9:33 AM, Dariusz Marcinkiewicz wrote:
> This patch proposes to introduce explicit mapping between DRM connectors
> and /dev/cecX adapters.
> 
> This is achieved here by adding a new structure with connector info
> (card number and connector id in case of DRM connectors) to cec_adapter.
> That connector info is expected to be set either by a code creating
> an adapter or trough a CEC notifier (which is extended for that purpose).
> 
> New ioctl, exposing connector info to userland, is added to /dev/cec.
> 
> Changes since v1:
>  - removed the unnecessary event,
>  - extended cec_connctor_info to allow for various types of connectors.
> 
> Signed-off-by: Dariusz Marcinkiewicz <darekm@google.com>
> ---
>  .../display/amdgpu_dm/amdgpu_dm_mst_types.c   |  2 +-
>  drivers/gpu/drm/drm_dp_cec.c                  | 24 +++++++++-----
>  drivers/gpu/drm/i915/intel_dp.c               |  5 ++-
>  drivers/gpu/drm/i915/intel_hdmi.c             | 11 ++++++-
>  drivers/gpu/drm/nouveau/nouveau_connector.c   |  3 +-
>  drivers/media/cec/cec-adap.c                  |  7 +++++
>  drivers/media/cec/cec-api.c                   | 11 +++++++
>  drivers/media/cec/cec-core.c                  |  3 ++
>  drivers/media/cec/cec-notifier.c              | 19 +++++++++++-
>  include/drm/drm_dp_helper.h                   | 14 ++++-----
>  include/media/cec-notifier.h                  | 31 +++++++++++++++++--
>  include/media/cec.h                           | 11 ++++++-
>  include/uapi/linux/cec.h                      | 24 ++++++++++++++
>  13 files changed, 139 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> index c4ea3a91f17aa..41678df654cdc 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> @@ -379,7 +379,7 @@ void amdgpu_dm_initialize_dp_connector(struct amdgpu_display_manager *dm,
>  
>  	drm_dp_aux_register(&aconnector->dm_dp_aux.aux);
>  	drm_dp_cec_register_connector(&aconnector->dm_dp_aux.aux,
> -				      aconnector->base.name, dm->adev->dev);
> +				      &aconnector->base);
>  	aconnector->mst_mgr.cbs = &dm_mst_cbs;
>  	drm_dp_mst_topology_mgr_init(
>  		&aconnector->mst_mgr,
> diff --git a/drivers/gpu/drm/drm_dp_cec.c b/drivers/gpu/drm/drm_dp_cec.c
> index b15cee85b702b..c92aca0ff6320 100644
> --- a/drivers/gpu/drm/drm_dp_cec.c
> +++ b/drivers/gpu/drm/drm_dp_cec.c
> @@ -8,7 +8,9 @@
>  #include <linux/kernel.h>
>  #include <linux/module.h>
>  #include <linux/slab.h>
> +#include <drm/drm_connector.h>
>  #include <drm/drm_dp_helper.h>
> +#include <drm/drmP.h>
>  #include <media/cec.h>
>  
>  /*
> @@ -295,6 +297,7 @@ static void drm_dp_cec_unregister_work(struct work_struct *work)
>   */
>  void drm_dp_cec_set_edid(struct drm_dp_aux *aux, const struct edid *edid)
>  {
> +	struct drm_connector *connector = aux->cec.connector;
>  	u32 cec_caps = CEC_CAP_DEFAULTS | CEC_CAP_NEEDS_HPD;
>  	unsigned int num_las = 1;
>  	u8 cap;
> @@ -344,16 +347,23 @@ void drm_dp_cec_set_edid(struct drm_dp_aux *aux, const struct edid *edid)
>  
>  	/* Create a new adapter */
>  	aux->cec.adap = cec_allocate_adapter(&drm_dp_cec_adap_ops,
> -					     aux, aux->cec.name, cec_caps,
> +					     aux, connector->name, cec_caps,
>  					     num_las);
>  	if (IS_ERR(aux->cec.adap)) {
>  		aux->cec.adap = NULL;
>  		goto unlock;
>  	}
> -	if (cec_register_adapter(aux->cec.adap, aux->cec.parent)) {
> +	if (cec_register_adapter(aux->cec.adap, connector->dev->dev)) {
>  		cec_delete_adapter(aux->cec.adap);
>  		aux->cec.adap = NULL;
>  	} else {
> +		struct cec_connector_info info;
> +
> +		info.type = CEC_CONNECTOR_TYPE_DRM;
> +		info.drm.card_no = connector->dev->primary->index;
> +		info.drm.connector_id = connector->base.id;
> +		cec_s_connector_info(aux->cec.adap, connector);

Don't add this new function, just pass the information as an argument to
cec_allocate_adapter. That way the adapter information is correct before
the cec device is registered.

If there is no connector information, then just pass NULL to cec_allocate_adapter().

> +
>  		/*
>  		 * Update the phys addr for the new CEC adapter. When called
>  		 * from drm_dp_cec_register_connector() edid == NULL, so in
> @@ -406,22 +416,20 @@ EXPORT_SYMBOL(drm_dp_cec_unset_edid);
>  /**
>   * drm_dp_cec_register_connector() - register a new connector
>   * @aux: DisplayPort AUX channel
> - * @name: name of the CEC device
> - * @parent: parent device
> + * @connector: drm connector
>   *
>   * A new connector was registered with associated CEC adapter name and
>   * CEC adapter parent device. After registering the name and parent
>   * drm_dp_cec_set_edid() is called to check if the connector supports
>   * CEC and to register a CEC adapter if that is the case.
>   */
> -void drm_dp_cec_register_connector(struct drm_dp_aux *aux, const char *name,
> -				   struct device *parent)
> +void drm_dp_cec_register_connector(struct drm_dp_aux *aux,
> +				   struct drm_connector *connector)
>  {
>  	WARN_ON(aux->cec.adap);
>  	if (WARN_ON(!aux->transfer))
>  		return;
> -	aux->cec.name = name;
> -	aux->cec.parent = parent;
> +	aux->cec.connector = connector;
>  	INIT_DELAYED_WORK(&aux->cec.unregister_work,
>  			  drm_dp_cec_unregister_work);
>  }
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index cf709835fb9a9..1d451999c4cc1 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -5542,7 +5542,6 @@ static int
>  intel_dp_connector_register(struct drm_connector *connector)
>  {
>  	struct intel_dp *intel_dp = intel_attached_dp(connector);
> -	struct drm_device *dev = connector->dev;
>  	int ret;
>  
>  	ret = intel_connector_register(connector);
> @@ -5557,8 +5556,7 @@ intel_dp_connector_register(struct drm_connector *connector)
>  	intel_dp->aux.dev = connector->kdev;
>  	ret = drm_dp_aux_register(&intel_dp->aux);
>  	if (!ret)
> -		drm_dp_cec_register_connector(&intel_dp->aux,
> -					      connector->name, dev->dev);
> +		drm_dp_cec_register_connector(&intel_dp->aux, connector);
>  	return ret;
>  }
>  
> @@ -7107,3 +7105,4 @@ void intel_dp_mst_resume(struct drm_i915_private *dev_priv)
>  		}
>  	}
>  }
> +
> diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
> index f125a62eba8cf..228f58f568ef1 100644
> --- a/drivers/gpu/drm/i915/intel_hdmi.c
> +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> @@ -2448,8 +2448,17 @@ void intel_hdmi_init_connector(struct intel_digital_port *intel_dig_port,
>  
>  	intel_hdmi->cec_notifier = cec_notifier_get_conn(dev->dev,
>  							 port_identifier(port));
> -	if (!intel_hdmi->cec_notifier)
> +	if (intel_hdmi->cec_notifier) {
> +		struct cec_connector_info info;
> +
> +		info.type = CEC_CONNECTOR_TYPE_DRM;
> +		info.drm.card_no = connector->dev->primary->index;
> +		info.drm.connector_id = connector->base.id;
> +		cec_notifier_set_connector_info(intel_hdmi->cec_notifier,
> +						&info);

Same here: the connector info should be passed as an argument to cec_notifier_get_conn()
and stored in the cec_notifier struct.

The CEC driver calls cec_notifier_get() and can then pass the connector_info to the
cec_allocate_adapter() call.

> +	} else {
>  		DRM_DEBUG_KMS("CEC notifier get failed\n");
> +	}
>  }
>  
>  void intel_hdmi_init(struct drm_i915_private *dev_priv,
> diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.c b/drivers/gpu/drm/nouveau/nouveau_connector.c
> index 4116ee62adafe..4438824ca88b0 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_connector.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_connector.c
> @@ -1413,8 +1413,7 @@ nouveau_connector_create(struct drm_device *dev,
>  	switch (type) {
>  	case DRM_MODE_CONNECTOR_DisplayPort:
>  	case DRM_MODE_CONNECTOR_eDP:
> -		drm_dp_cec_register_connector(&nv_connector->aux,
> -					      connector->name, dev->dev);
> +		drm_dp_cec_register_connector(&nv_connector->aux, connector);
>  		break;
>  	}
>  
> diff --git a/drivers/media/cec/cec-adap.c b/drivers/media/cec/cec-adap.c
> index f1261cc2b6fa5..88f42c5e8512f 100644
> --- a/drivers/media/cec/cec-adap.c
> +++ b/drivers/media/cec/cec-adap.c
> @@ -1566,6 +1566,13 @@ void cec_s_phys_addr_from_edid(struct cec_adapter *adap,
>  }
>  EXPORT_SYMBOL_GPL(cec_s_phys_addr_from_edid);
>  
> +void cec_s_connector_info(struct cec_adapter *adap,
> +			  struct cec_connector_info *info)
> +{
> +	memcpy(&adap->connector, info, sizeof(*info));
> +}
> +EXPORT_SYMBOL_GPL(cec_s_connector_info);
> +
>  /*
>   * Called from either the ioctl or a driver to set the logical addresses.
>   *
> diff --git a/drivers/media/cec/cec-api.c b/drivers/media/cec/cec-api.c
> index 156a0d76ab2a1..0394a77d5bb5c 100644
> --- a/drivers/media/cec/cec-api.c
> +++ b/drivers/media/cec/cec-api.c
> @@ -187,6 +187,14 @@ static long cec_adap_s_log_addrs(struct cec_adapter *adap, struct cec_fh *fh,
>  	return 0;
>  }
>  
> +static long cec_adap_g_connector_info(struct cec_adapter *adap,
> +				      struct cec_connector_info __user *parg)
> +{
> +	if (copy_to_user(parg, &adap->connector, sizeof(adap->connector)))
> +		return -EFAULT;
> +	return 0;
> +}
> +
>  static long cec_transmit(struct cec_adapter *adap, struct cec_fh *fh,
>  			 bool block, struct cec_msg __user *parg)
>  {
> @@ -514,6 +522,9 @@ static long cec_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>  	case CEC_ADAP_S_LOG_ADDRS:
>  		return cec_adap_s_log_addrs(adap, fh, block, parg);
>  
> +	case CEC_ADAP_G_CONNECTOR_INFO:
> +		return cec_adap_g_connector_info(adap, parg);
> +
>  	case CEC_TRANSMIT:
>  		return cec_transmit(adap, fh, block, parg);
>  
> diff --git a/drivers/media/cec/cec-core.c b/drivers/media/cec/cec-core.c
> index cc875dabd7658..7b0e28263195a 100644
> --- a/drivers/media/cec/cec-core.c
> +++ b/drivers/media/cec/cec-core.c
> @@ -195,6 +195,9 @@ void cec_register_cec_notifier(struct cec_adapter *adap,
>  
>  	adap->notifier = notifier;
>  	cec_notifier_register(adap->notifier, adap, cec_cec_notify);
> +
> +	cec_s_connector_info(adap,
> +			     cec_notifier_get_connector_info(notifier));
>  }
>  EXPORT_SYMBOL_GPL(cec_register_cec_notifier);
>  #endif
> diff --git a/drivers/media/cec/cec-notifier.c b/drivers/media/cec/cec-notifier.c
> index dd2078b27a419..a3c172ee0999b 100644
> --- a/drivers/media/cec/cec-notifier.c
> +++ b/drivers/media/cec/cec-notifier.c
> @@ -26,6 +26,7 @@ struct cec_notifier {
>  	void (*callback)(struct cec_adapter *adap, u16 pa);
>  
>  	u16 phys_addr;
> +	struct cec_connector_info connector_info;
>  };
>  
>  static LIST_HEAD(cec_notifiers);
> @@ -51,6 +52,7 @@ struct cec_notifier *cec_notifier_get_conn(struct device *dev, const char *conn)
>  	if (conn)
>  		n->conn = kstrdup(conn, GFP_KERNEL);
>  	n->phys_addr = CEC_PHYS_ADDR_INVALID;
> +	n->connector_info.type = CEC_CONNECTOR_TYPE_NO_CONNECTOR;
>  	mutex_init(&n->lock);
>  	kref_init(&n->kref);
>  	list_add_tail(&n->head, &cec_notifiers);
> @@ -106,9 +108,24 @@ void cec_notifier_set_phys_addr_from_edid(struct cec_notifier *n,
>  }
>  EXPORT_SYMBOL_GPL(cec_notifier_set_phys_addr_from_edid);
>  
> +void cec_notifier_set_connector_info(struct cec_notifier *n,
> +				     struct cec_connector_info *c)
> +{
> +	memcpy(&n->connector_info, c, sizeof(*c));
> +}
> +EXPORT_SYMBOL_GPL(cec_notifier_set_connector_info);
> +
> +struct cec_connector_info *cec_notifier_get_connector_info(
> +	struct cec_notifier *n)
> +{
> +	return &n->connector_info;
> +}
> +EXPORT_SYMBOL_GPL(cec_notifier_get_connector_info);
> +
>  void cec_notifier_register(struct cec_notifier *n,
>  			   struct cec_adapter *adap,
> -			   void (*callback)(struct cec_adapter *adap, u16 pa))
> +			   void (*callback)(struct cec_adapter *adap,
> +					    u16 pa))
>  {
>  	kref_get(&n->kref);
>  	mutex_lock(&n->lock);
> diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
> index 97ce790a5b5aa..ded0ff01f2ac7 100644
> --- a/include/drm/drm_dp_helper.h
> +++ b/include/drm/drm_dp_helper.h
> @@ -1208,6 +1208,7 @@ struct drm_dp_aux_msg {
>  
>  struct cec_adapter;
>  struct edid;
> +struct drm_connector;
>  
>  /**
>   * struct drm_dp_aux_cec - DisplayPort CEC-Tunneling-over-AUX
> @@ -1220,8 +1221,7 @@ struct edid;
>  struct drm_dp_aux_cec {
>  	struct mutex lock;
>  	struct cec_adapter *adap;
> -	const char *name;
> -	struct device *parent;
> +	struct drm_connector *connector;
>  	struct delayed_work unregister_work;
>  };
>  
> @@ -1418,8 +1418,8 @@ drm_dp_has_quirk(const struct drm_dp_desc *desc, enum drm_dp_quirk quirk)
>  
>  #ifdef CONFIG_DRM_DP_CEC
>  void drm_dp_cec_irq(struct drm_dp_aux *aux);
> -void drm_dp_cec_register_connector(struct drm_dp_aux *aux, const char *name,
> -				   struct device *parent);
> +void drm_dp_cec_register_connector(struct drm_dp_aux *aux,
> +				   struct drm_connector *connector);
>  void drm_dp_cec_unregister_connector(struct drm_dp_aux *aux);
>  void drm_dp_cec_set_edid(struct drm_dp_aux *aux, const struct edid *edid);
>  void drm_dp_cec_unset_edid(struct drm_dp_aux *aux);
> @@ -1428,9 +1428,9 @@ static inline void drm_dp_cec_irq(struct drm_dp_aux *aux)
>  {
>  }
>  
> -static inline void drm_dp_cec_register_connector(struct drm_dp_aux *aux,
> -						 const char *name,
> -						 struct device *parent)
> +static inline
> +void drm_dp_cec_register_connector(struct drm_dp_aux *aux,
> +				   struct drm_connector *connector)
>  {
>  }
>  
> diff --git a/include/media/cec-notifier.h b/include/media/cec-notifier.h
> index 814eeef35a5cf..f6a7572920f3f 100644
> --- a/include/media/cec-notifier.h
> +++ b/include/media/cec-notifier.h
> @@ -63,6 +63,21 @@ void cec_notifier_set_phys_addr(struct cec_notifier *n, u16 pa);
>  void cec_notifier_set_phys_addr_from_edid(struct cec_notifier *n,
>  					  const struct edid *edid);
>  
> +/**
> + * cec_notifier_get_connector_info - get connector info associatied with
> + * a notifier
> + * @n: the CEC notifier
> + */
> +struct cec_connector_info *cec_notifier_get_connector_info(
> +				struct cec_notifier *n);
> +
> +/**
> + * cec_notifier_set_connector_info - associates connector info with a notifier
> + * @n: the CEC notifier
> + * @c: the connector info
> + */
> +void cec_notifier_set_connector_info(struct cec_notifier *n,
> +				     struct cec_connector_info *c);
>  /**
>   * cec_notifier_register - register a callback with the notifier
>   * @n: the CEC notifier
> @@ -108,9 +123,21 @@ static inline void cec_notifier_set_phys_addr_from_edid(struct cec_notifier *n,
>  {
>  }
>  
> +const struct cec_connector_info*
> +	cec_notifier_get_connector_info(struct cec_notifier *n)
> +{
> +	return (struct cec_connector_info *)0xdeadfeed;
> +}
> +
> +static inline void cec_notifier_set_connector_info(
> +			struct cec_notifier *n,
> +			struct cec_connector_info *c)
> +{
> +}
> +
>  static inline void cec_notifier_register(struct cec_notifier *n,
> -			 struct cec_adapter *adap,
> -			 void (*callback)(struct cec_adapter *adap, u16 pa))
> +			struct cec_adapter *adap,
> +			void (*callback)(struct cec_adapter *adap, u16 pa))
>  {
>  }
>  
> diff --git a/include/media/cec.h b/include/media/cec.h
> index 707411ef8ba28..b19b6efb4a23a 100644
> --- a/include/media/cec.h
> +++ b/include/media/cec.h
> @@ -200,6 +200,8 @@ struct cec_adapter {
>  	u32 sequence;
>  
>  	char input_phys[32];
> +
> +	struct cec_connector_info connector;
>  };
>  
>  static inline void *cec_get_drvdata(const struct cec_adapter *adap)
> @@ -247,9 +249,11 @@ void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr,
>  		     bool block);
>  void cec_s_phys_addr_from_edid(struct cec_adapter *adap,
>  			       const struct edid *edid);
> +void cec_s_connector_info(struct cec_adapter *adap,
> +			  struct cec_connector_info *connector);
> +
>  int cec_transmit_msg(struct cec_adapter *adap, struct cec_msg *msg,
>  		     bool block);
> -
>  /* Called by the adapter */
>  void cec_transmit_done_ts(struct cec_adapter *adap, u8 status,
>  			  u8 arb_lost_cnt, u8 nack_cnt, u8 low_drive_cnt,
> @@ -357,6 +361,11 @@ static inline void cec_s_phys_addr_from_edid(struct cec_adapter *adap,
>  {
>  }
>  
> +void cec_s_connector_info(struct cec_adapter *adap, int card_no,
> +			  u32 connector_id)
> +{
> +}
> +
>  static inline u16 cec_get_edid_phys_addr(const u8 *edid, unsigned int size,
>  					 unsigned int *offset)
>  {
> diff --git a/include/uapi/linux/cec.h b/include/uapi/linux/cec.h
> index 3094af68b6e76..618ef95ce79a1 100644
> --- a/include/uapi/linux/cec.h
> +++ b/include/uapi/linux/cec.h
> @@ -411,6 +411,27 @@ struct cec_event_lost_msgs {
>  	__u32 lost_msgs;
>  };
>  
> +/**
> + * struct cec_event_connector - tells if and which connector is associated
> + * with the CEC adapter.
> + * @card_no: drm card number, -1 if no connector
> + * @connector_id: drm connector id.
> + */
> +struct cec_drm_connector_info {
> +	int card_no;
> +	__u32 connector_id;
> +};
> +
> +#define CEC_CONNECTOR_TYPE_NO_CONNECTOR	0
> +#define CEC_CONNECTOR_TYPE_DRM		1
> +struct cec_connector_info {
> +	int type;
> +	union {
> +		struct cec_drm_connector_info drm;
> +		__u32 raw[16];
> +	};
> +};
> +
>  /**
>   * struct cec_event - CEC event structure
>   * @ts: the timestamp of when the event was sent.
> @@ -475,6 +496,9 @@ struct cec_event {
>  #define CEC_G_MODE		_IOR('a',  8, __u32)
>  #define CEC_S_MODE		_IOW('a',  9, __u32)
>  
> +/* Gets the connector info */
> +#define CEC_ADAP_G_CONNECTOR_INFO _IOR('a',  10, struct cec_connector_info)
> +
>  /*
>   * The remainder of this header defines all CEC messages and operands.
>   * The format matters since it the cec-ctl utility parses it to generate
> 

Regards,

	Hans