diff mbox

[RFCv2,1/5] video: add HDMI state notifier support

Message ID 1479136968-24477-2-git-send-email-hverkuil@xs4all.nl (mailing list archive)
State RFC, archived
Delegated to: Hans Verkuil
Headers

Commit Message

Hans Verkuil Nov. 14, 2016, 3:22 p.m. UTC 
  From: Hans Verkuil <hans.verkuil@cisco.com>

Add support for HDMI hotplug and EDID notifiers, which is used to convey
information from HDMI drivers to their CEC and audio counterparts.

Based on an earlier version from Russell King:

https://patchwork.kernel.org/patch/9277043/

The hdmi_notifier is a reference counted object containing the HDMI state
of an HDMI device.

When a new notifier is registered the current state will be reported to
that notifier at registration time.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 drivers/video/Kconfig         |   3 +
 drivers/video/Makefile        |   1 +
 drivers/video/hdmi-notifier.c | 136 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/hdmi-notifier.h |  43 +++++++++++++
 4 files changed, 183 insertions(+)
 create mode 100644 drivers/video/hdmi-notifier.c
 create mode 100644 include/linux/hdmi-notifier.h

Comments

Philipp Zabel Nov. 15, 2016, 6:24 p.m. UTC | #1 
Hi Hans,

Am Montag, den 14.11.2016, 16:22 +0100 schrieb Hans Verkuil:
> From: Hans Verkuil <hans.verkuil@cisco.com>
> 
> Add support for HDMI hotplug and EDID notifiers, which is used to convey
> information from HDMI drivers to their CEC and audio counterparts.
> 
> Based on an earlier version from Russell King:
> 
> https://patchwork.kernel.org/patch/9277043/
> 
> The hdmi_notifier is a reference counted object containing the HDMI state
> of an HDMI device.
> 
> When a new notifier is registered the current state will be reported to
> that notifier at registration time.
> 
> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
> ---
>  drivers/video/Kconfig         |   3 +
>  drivers/video/Makefile        |   1 +
>  drivers/video/hdmi-notifier.c | 136 ++++++++++++++++++++++++++++++++++++++++++
>  include/linux/hdmi-notifier.h |  43 +++++++++++++
>  4 files changed, 183 insertions(+)
>  create mode 100644 drivers/video/hdmi-notifier.c
>  create mode 100644 include/linux/hdmi-notifier.h
> 
> diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
> index 3c20af9..1ee7b9f 100644
> --- a/drivers/video/Kconfig
> +++ b/drivers/video/Kconfig
> @@ -36,6 +36,9 @@ config VIDEOMODE_HELPERS
>  config HDMI
>  	bool
>  
> +config HDMI_NOTIFIERS
> +	bool
> +
>  if VT
>  	source "drivers/video/console/Kconfig"
>  endif
> diff --git a/drivers/video/Makefile b/drivers/video/Makefile
> index 9ad3c17..65f5649 100644
> --- a/drivers/video/Makefile
> +++ b/drivers/video/Makefile
> @@ -1,5 +1,6 @@
>  obj-$(CONFIG_VGASTATE)            += vgastate.o
>  obj-$(CONFIG_HDMI)                += hdmi.o
> +obj-$(CONFIG_HDMI_NOTIFIERS)      += hdmi-notifier.o
>  
>  obj-$(CONFIG_VT)		  += console/
>  obj-$(CONFIG_LOGO)		  += logo/
> diff --git a/drivers/video/hdmi-notifier.c b/drivers/video/hdmi-notifier.c
> new file mode 100644
> index 0000000..c2a4f1b
> --- /dev/null
> +++ b/drivers/video/hdmi-notifier.c
> @@ -0,0 +1,136 @@
> +#include <linux/export.h>
> +#include <linux/hdmi-notifier.h>
> +#include <linux/string.h>
> +#include <linux/slab.h>
> +#include <linux/list.h>
> +
> +struct hdmi_notifiers {
> +	struct list_head head;
> +	struct device *dev;
> +	struct hdmi_notifier *n;
> +};

This struct is not used, can be removed.

> +static LIST_HEAD(hdmi_notifiers);
> +static DEFINE_MUTEX(hdmi_notifiers_lock);
> +
> +struct hdmi_notifier *hdmi_notifier_get(struct device *dev)
> +{
> +	struct hdmi_notifier *n;
> +
> +	mutex_lock(&hdmi_notifiers_lock);
> +	list_for_each_entry(n, &hdmi_notifiers, head) {
> +		if (n->dev == dev) {
> +			mutex_unlock(&hdmi_notifiers_lock);
> +			kref_get(&n->kref);
> +			return n;
> +		}
> +	}
> +	n = kzalloc(sizeof(*n), GFP_KERNEL);
> +	if (!n)
> +		goto unlock;
> +	mutex_init(&n->lock);
> +	BLOCKING_INIT_NOTIFIER_HEAD(&n->notifiers);
> +	kref_init(&n->kref);

+	n->dev = dev;

Currently n->dev is never set, so every caller of this function gets its
own hdmi_notifier.

> +	list_add_tail(&n->head, &hdmi_notifiers);
> +unlock:
> +	mutex_unlock(&hdmi_notifiers_lock);
> +	return n;
> +}
> +EXPORT_SYMBOL_GPL(hdmi_notifier_get);
> +
> +static void hdmi_notifier_release(struct kref *kref)
> +{
> +	struct hdmi_notifier *n =
> +		container_of(kref, struct hdmi_notifier, kref);
> +
> +	kfree(n->edid);
> +	kfree(n);
> +}
> +
> +void hdmi_notifier_put(struct hdmi_notifier *n)
> +{
> +	kref_put(&n->kref, hdmi_notifier_release);
> +}
> +EXPORT_SYMBOL_GPL(hdmi_notifier_put);
> +
> +int hdmi_notifier_register(struct hdmi_notifier *n, struct notifier_block *nb)
> +{
> +	int ret = blocking_notifier_chain_register(&n->notifiers, nb);
> +
> +	if (ret)
> +		return ret;
> +	kref_get(&n->kref);
> +	mutex_lock(&n->lock);
> +	if (n->connected) {
> +		blocking_notifier_call_chain(&n->notifiers, HDMI_CONNECTED, n);
> +		if (n->edid_size)
> +			blocking_notifier_call_chain(&n->notifiers, HDMI_NEW_EDID, n);
> +		if (n->has_eld)
> +			blocking_notifier_call_chain(&n->notifiers, HDMI_NEW_ELD, n);
> +	}
> +	mutex_unlock(&n->lock);
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(hdmi_notifier_register);
> +
> +int hdmi_notifier_unregister(struct hdmi_notifier *n, struct notifier_block *nb)
> +{
> +	int ret = blocking_notifier_chain_unregister(&n->notifiers, nb);
> +
> +	if (ret == 0)
> +		hdmi_notifier_put(n);
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(hdmi_notifier_unregister);
> +
> +void hdmi_event_connect(struct hdmi_notifier *n)
> +{
> +	mutex_lock(&n->lock);
> +	n->connected = true;
> +	blocking_notifier_call_chain(&n->notifiers, HDMI_CONNECTED, n);
> +	mutex_unlock(&n->lock);
> +}
> +EXPORT_SYMBOL_GPL(hdmi_event_connect);
> +
> +void hdmi_event_disconnect(struct hdmi_notifier *n)
> +{
> +	mutex_lock(&n->lock);
> +	n->connected = false;
> +	n->has_eld = false;
> +	n->edid_size = 0;
> +	blocking_notifier_call_chain(&n->notifiers, HDMI_DISCONNECTED, n);
> +	mutex_unlock(&n->lock);
> +}
> +EXPORT_SYMBOL_GPL(hdmi_event_disconnect);
> +
> +int hdmi_event_new_edid(struct hdmi_notifier *n, const void *edid, size_t size)
> +{
> +	mutex_lock(&n->lock);
> +	if (n->edid_allocated_size < size) {
> +		void *p = kmalloc(size, GFP_KERNEL);
> +
> +		if (p == NULL) {
> +			mutex_unlock(&n->lock);
> +			return -ENOMEM;
> +		}
> +		kfree(n->edid);
> +		n->edid = p;
> +		n->edid_allocated_size = size;
> +	}
> +	memcpy(n->edid, edid, size);
> +	n->edid_size = size;
> +	blocking_notifier_call_chain(&n->notifiers, HDMI_NEW_EDID, n);
> +	mutex_unlock(&n->lock);
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(hdmi_event_new_edid);
> +
> +void hdmi_event_new_eld(struct hdmi_notifier *n, const u8 eld[128])
> +{
> +	mutex_lock(&n->lock);
> +	memcpy(n->eld, eld, sizeof(n->eld));
> +	n->has_eld = true;
> +	blocking_notifier_call_chain(&n->notifiers, HDMI_NEW_ELD, n);
> +	mutex_unlock(&n->lock);
> +}
> +EXPORT_SYMBOL_GPL(hdmi_event_new_eld);
> diff --git a/include/linux/hdmi-notifier.h b/include/linux/hdmi-notifier.h
> new file mode 100644
> index 0000000..f7fc405
> --- /dev/null
> +++ b/include/linux/hdmi-notifier.h
> @@ -0,0 +1,43 @@
> +#ifndef LINUX_HDMI_NOTIFIER_H
> +#define LINUX_HDMI_NOTIFIER_H
> +
> +#include <linux/types.h>
> +#include <linux/notifier.h>
> +#include <linux/kref.h>
> +
> +enum {
> +	HDMI_CONNECTED,
> +	HDMI_DISCONNECTED,
> +	HDMI_NEW_EDID,
> +	HDMI_NEW_ELD,
> +};
> +
> +struct device;
> +
> +struct hdmi_notifier {
> +	struct mutex lock;
> +	struct list_head head;
> +	struct kref kref;
> +	struct blocking_notifier_head notifiers;
> +	struct device *dev;
> +
> +	/* Current state */
> +	bool connected;
> +	bool has_eld;
> +	unsigned char eld[128];
> +	void *edid;
> +	size_t edid_size;
> +	size_t edid_allocated_size;
> +};
> +
> +struct hdmi_notifier *hdmi_notifier_get(struct device *dev);
> +void hdmi_notifier_put(struct hdmi_notifier *n);
> +int hdmi_notifier_register(struct hdmi_notifier *n, struct notifier_block *nb);
> +int hdmi_notifier_unregister(struct hdmi_notifier *n, struct notifier_block *nb);
> +
> +void hdmi_event_connect(struct hdmi_notifier *n);
> +void hdmi_event_disconnect(struct hdmi_notifier *n);
> +int hdmi_event_new_edid(struct hdmi_notifier *n, const void *edid, size_t size);
> +void hdmi_event_new_eld(struct hdmi_notifier *n, const u8 eld[128]);
> +
> +#endif

With the above change,

Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Tested-by: Philipp Zabel <p.zabel@pengutronix.de> (on MT8173)

I'll send the patches for mediatek-drm and hdmi-codec that I used for
testing in a bit.

regards
Philipp

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Hans Verkuil Nov. 15, 2016, 8:41 p.m. UTC | #2 
Hi Philipp,

On 11/15/2016 07:24 PM, Philipp Zabel wrote:
> Hi Hans,
> 
> Am Montag, den 14.11.2016, 16:22 +0100 schrieb Hans Verkuil:
>> From: Hans Verkuil <hans.verkuil@cisco.com>
>>
>> Add support for HDMI hotplug and EDID notifiers, which is used to convey
>> information from HDMI drivers to their CEC and audio counterparts.
>>
>> Based on an earlier version from Russell King:
>>
>> https://patchwork.kernel.org/patch/9277043/
>>
>> The hdmi_notifier is a reference counted object containing the HDMI state
>> of an HDMI device.
>>
>> When a new notifier is registered the current state will be reported to
>> that notifier at registration time.
>>
>> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
>> ---
>>  drivers/video/Kconfig         |   3 +
>>  drivers/video/Makefile        |   1 +
>>  drivers/video/hdmi-notifier.c | 136 ++++++++++++++++++++++++++++++++++++++++++
>>  include/linux/hdmi-notifier.h |  43 +++++++++++++
>>  4 files changed, 183 insertions(+)
>>  create mode 100644 drivers/video/hdmi-notifier.c
>>  create mode 100644 include/linux/hdmi-notifier.h
>>
>> diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
>> index 3c20af9..1ee7b9f 100644
>> --- a/drivers/video/Kconfig
>> +++ b/drivers/video/Kconfig
>> @@ -36,6 +36,9 @@ config VIDEOMODE_HELPERS
>>  config HDMI
>>  	bool
>>  
>> +config HDMI_NOTIFIERS
>> +	bool
>> +
>>  if VT
>>  	source "drivers/video/console/Kconfig"
>>  endif
>> diff --git a/drivers/video/Makefile b/drivers/video/Makefile
>> index 9ad3c17..65f5649 100644
>> --- a/drivers/video/Makefile
>> +++ b/drivers/video/Makefile
>> @@ -1,5 +1,6 @@
>>  obj-$(CONFIG_VGASTATE)            += vgastate.o
>>  obj-$(CONFIG_HDMI)                += hdmi.o
>> +obj-$(CONFIG_HDMI_NOTIFIERS)      += hdmi-notifier.o
>>  
>>  obj-$(CONFIG_VT)		  += console/
>>  obj-$(CONFIG_LOGO)		  += logo/
>> diff --git a/drivers/video/hdmi-notifier.c b/drivers/video/hdmi-notifier.c
>> new file mode 100644
>> index 0000000..c2a4f1b
>> --- /dev/null
>> +++ b/drivers/video/hdmi-notifier.c
>> @@ -0,0 +1,136 @@
>> +#include <linux/export.h>
>> +#include <linux/hdmi-notifier.h>
>> +#include <linux/string.h>
>> +#include <linux/slab.h>
>> +#include <linux/list.h>
>> +
>> +struct hdmi_notifiers {
>> +	struct list_head head;
>> +	struct device *dev;
>> +	struct hdmi_notifier *n;
>> +};
> 
> This struct is not used, can be removed.

Indeed.

> 
>> +static LIST_HEAD(hdmi_notifiers);
>> +static DEFINE_MUTEX(hdmi_notifiers_lock);
>> +
>> +struct hdmi_notifier *hdmi_notifier_get(struct device *dev)
>> +{
>> +	struct hdmi_notifier *n;
>> +
>> +	mutex_lock(&hdmi_notifiers_lock);
>> +	list_for_each_entry(n, &hdmi_notifiers, head) {
>> +		if (n->dev == dev) {
>> +			mutex_unlock(&hdmi_notifiers_lock);
>> +			kref_get(&n->kref);
>> +			return n;
>> +		}
>> +	}
>> +	n = kzalloc(sizeof(*n), GFP_KERNEL);
>> +	if (!n)
>> +		goto unlock;
>> +	mutex_init(&n->lock);
>> +	BLOCKING_INIT_NOTIFIER_HEAD(&n->notifiers);
>> +	kref_init(&n->kref);
> 
> +	n->dev = dev;
> 
> Currently n->dev is never set, so every caller of this function gets its
> own hdmi_notifier.

Oops! Well, I did say it was compile-tested only :-)

> 
>> +	list_add_tail(&n->head, &hdmi_notifiers);
>> +unlock:
>> +	mutex_unlock(&hdmi_notifiers_lock);
>> +	return n;
>> +}
>> +EXPORT_SYMBOL_GPL(hdmi_notifier_get);
>> +
>> +static void hdmi_notifier_release(struct kref *kref)
>> +{
>> +	struct hdmi_notifier *n =
>> +		container_of(kref, struct hdmi_notifier, kref);
>> +
>> +	kfree(n->edid);
>> +	kfree(n);
>> +}
>> +
>> +void hdmi_notifier_put(struct hdmi_notifier *n)
>> +{
>> +	kref_put(&n->kref, hdmi_notifier_release);
>> +}
>> +EXPORT_SYMBOL_GPL(hdmi_notifier_put);
>> +
>> +int hdmi_notifier_register(struct hdmi_notifier *n, struct notifier_block *nb)
>> +{
>> +	int ret = blocking_notifier_chain_register(&n->notifiers, nb);
>> +
>> +	if (ret)
>> +		return ret;
>> +	kref_get(&n->kref);
>> +	mutex_lock(&n->lock);
>> +	if (n->connected) {
>> +		blocking_notifier_call_chain(&n->notifiers, HDMI_CONNECTED, n);
>> +		if (n->edid_size)
>> +			blocking_notifier_call_chain(&n->notifiers, HDMI_NEW_EDID, n);
>> +		if (n->has_eld)
>> +			blocking_notifier_call_chain(&n->notifiers, HDMI_NEW_ELD, n);
>> +	}
>> +	mutex_unlock(&n->lock);
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(hdmi_notifier_register);
>> +
>> +int hdmi_notifier_unregister(struct hdmi_notifier *n, struct notifier_block *nb)
>> +{
>> +	int ret = blocking_notifier_chain_unregister(&n->notifiers, nb);
>> +
>> +	if (ret == 0)
>> +		hdmi_notifier_put(n);
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(hdmi_notifier_unregister);
>> +
>> +void hdmi_event_connect(struct hdmi_notifier *n)
>> +{
>> +	mutex_lock(&n->lock);
>> +	n->connected = true;
>> +	blocking_notifier_call_chain(&n->notifiers, HDMI_CONNECTED, n);
>> +	mutex_unlock(&n->lock);
>> +}
>> +EXPORT_SYMBOL_GPL(hdmi_event_connect);
>> +
>> +void hdmi_event_disconnect(struct hdmi_notifier *n)
>> +{
>> +	mutex_lock(&n->lock);
>> +	n->connected = false;
>> +	n->has_eld = false;
>> +	n->edid_size = 0;
>> +	blocking_notifier_call_chain(&n->notifiers, HDMI_DISCONNECTED, n);
>> +	mutex_unlock(&n->lock);
>> +}
>> +EXPORT_SYMBOL_GPL(hdmi_event_disconnect);
>> +
>> +int hdmi_event_new_edid(struct hdmi_notifier *n, const void *edid, size_t size)
>> +{
>> +	mutex_lock(&n->lock);
>> +	if (n->edid_allocated_size < size) {
>> +		void *p = kmalloc(size, GFP_KERNEL);
>> +
>> +		if (p == NULL) {
>> +			mutex_unlock(&n->lock);
>> +			return -ENOMEM;
>> +		}
>> +		kfree(n->edid);
>> +		n->edid = p;
>> +		n->edid_allocated_size = size;
>> +	}
>> +	memcpy(n->edid, edid, size);
>> +	n->edid_size = size;
>> +	blocking_notifier_call_chain(&n->notifiers, HDMI_NEW_EDID, n);
>> +	mutex_unlock(&n->lock);
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(hdmi_event_new_edid);
>> +
>> +void hdmi_event_new_eld(struct hdmi_notifier *n, const u8 eld[128])
>> +{
>> +	mutex_lock(&n->lock);
>> +	memcpy(n->eld, eld, sizeof(n->eld));
>> +	n->has_eld = true;
>> +	blocking_notifier_call_chain(&n->notifiers, HDMI_NEW_ELD, n);
>> +	mutex_unlock(&n->lock);
>> +}
>> +EXPORT_SYMBOL_GPL(hdmi_event_new_eld);
>> diff --git a/include/linux/hdmi-notifier.h b/include/linux/hdmi-notifier.h
>> new file mode 100644
>> index 0000000..f7fc405
>> --- /dev/null
>> +++ b/include/linux/hdmi-notifier.h
>> @@ -0,0 +1,43 @@
>> +#ifndef LINUX_HDMI_NOTIFIER_H
>> +#define LINUX_HDMI_NOTIFIER_H
>> +
>> +#include <linux/types.h>
>> +#include <linux/notifier.h>
>> +#include <linux/kref.h>
>> +
>> +enum {
>> +	HDMI_CONNECTED,
>> +	HDMI_DISCONNECTED,
>> +	HDMI_NEW_EDID,
>> +	HDMI_NEW_ELD,
>> +};
>> +
>> +struct device;
>> +
>> +struct hdmi_notifier {
>> +	struct mutex lock;
>> +	struct list_head head;
>> +	struct kref kref;
>> +	struct blocking_notifier_head notifiers;
>> +	struct device *dev;
>> +
>> +	/* Current state */
>> +	bool connected;
>> +	bool has_eld;
>> +	unsigned char eld[128];
>> +	void *edid;
>> +	size_t edid_size;
>> +	size_t edid_allocated_size;
>> +};
>> +
>> +struct hdmi_notifier *hdmi_notifier_get(struct device *dev);
>> +void hdmi_notifier_put(struct hdmi_notifier *n);
>> +int hdmi_notifier_register(struct hdmi_notifier *n, struct notifier_block *nb);
>> +int hdmi_notifier_unregister(struct hdmi_notifier *n, struct notifier_block *nb);
>> +
>> +void hdmi_event_connect(struct hdmi_notifier *n);
>> +void hdmi_event_disconnect(struct hdmi_notifier *n);
>> +int hdmi_event_new_edid(struct hdmi_notifier *n, const void *edid, size_t size);
>> +void hdmi_event_new_eld(struct hdmi_notifier *n, const u8 eld[128]);
>> +
>> +#endif
> 
> With the above change,
> 
> Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
> Tested-by: Philipp Zabel <p.zabel@pengutronix.de> (on MT8173)
> 
> I'll send the patches for mediatek-drm and hdmi-codec that I used for
> testing in a bit.

Thanks for testing this so quickly! Much appreciated!

Regards,

	Hans
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Hans Verkuil Nov. 16, 2016, 9:43 a.m. UTC | #3 
On 11/15/16 21:41, Hans Verkuil wrote:
> Hi Philipp,
>
> On 11/15/2016 07:24 PM, Philipp Zabel wrote:
>> Hi Hans,
>>
>> Am Montag, den 14.11.2016, 16:22 +0100 schrieb Hans Verkuil:
>>> From: Hans Verkuil <hans.verkuil@cisco.com>
>>>
>>> Add support for HDMI hotplug and EDID notifiers, which is used to convey
>>> information from HDMI drivers to their CEC and audio counterparts.
>>>
>>> Based on an earlier version from Russell King:
>>>
>>> https://patchwork.kernel.org/patch/9277043/
>>>
>>> The hdmi_notifier is a reference counted object containing the HDMI state
>>> of an HDMI device.
>>>
>>> When a new notifier is registered the current state will be reported to
>>> that notifier at registration time.
>>>
>>> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
>>> ---
>>>  drivers/video/Kconfig         |   3 +
>>>  drivers/video/Makefile        |   1 +
>>>  drivers/video/hdmi-notifier.c | 136 ++++++++++++++++++++++++++++++++++++++++++
>>>  include/linux/hdmi-notifier.h |  43 +++++++++++++
>>>  4 files changed, 183 insertions(+)
>>>  create mode 100644 drivers/video/hdmi-notifier.c
>>>  create mode 100644 include/linux/hdmi-notifier.h
>>>
>>> diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
>>> index 3c20af9..1ee7b9f 100644
>>> --- a/drivers/video/Kconfig
>>> +++ b/drivers/video/Kconfig
>>> @@ -36,6 +36,9 @@ config VIDEOMODE_HELPERS
>>>  config HDMI
>>>  	bool
>>>
>>> +config HDMI_NOTIFIERS
>>> +	bool
>>> +
>>>  if VT
>>>  	source "drivers/video/console/Kconfig"
>>>  endif
>>> diff --git a/drivers/video/Makefile b/drivers/video/Makefile
>>> index 9ad3c17..65f5649 100644
>>> --- a/drivers/video/Makefile
>>> +++ b/drivers/video/Makefile
>>> @@ -1,5 +1,6 @@
>>>  obj-$(CONFIG_VGASTATE)            += vgastate.o
>>>  obj-$(CONFIG_HDMI)                += hdmi.o
>>> +obj-$(CONFIG_HDMI_NOTIFIERS)      += hdmi-notifier.o
>>>
>>>  obj-$(CONFIG_VT)		  += console/
>>>  obj-$(CONFIG_LOGO)		  += logo/
>>> diff --git a/drivers/video/hdmi-notifier.c b/drivers/video/hdmi-notifier.c
>>> new file mode 100644
>>> index 0000000..c2a4f1b
>>> --- /dev/null
>>> +++ b/drivers/video/hdmi-notifier.c
>>> @@ -0,0 +1,136 @@
>>> +#include <linux/export.h>
>>> +#include <linux/hdmi-notifier.h>
>>> +#include <linux/string.h>
>>> +#include <linux/slab.h>
>>> +#include <linux/list.h>
>>> +
>>> +struct hdmi_notifiers {
>>> +	struct list_head head;
>>> +	struct device *dev;
>>> +	struct hdmi_notifier *n;
>>> +};
>>
>> This struct is not used, can be removed.
>
> Indeed.
>
>>
>>> +static LIST_HEAD(hdmi_notifiers);
>>> +static DEFINE_MUTEX(hdmi_notifiers_lock);
>>> +
>>> +struct hdmi_notifier *hdmi_notifier_get(struct device *dev)
>>> +{
>>> +	struct hdmi_notifier *n;
>>> +
>>> +	mutex_lock(&hdmi_notifiers_lock);
>>> +	list_for_each_entry(n, &hdmi_notifiers, head) {
>>> +		if (n->dev == dev) {
>>> +			mutex_unlock(&hdmi_notifiers_lock);
>>> +			kref_get(&n->kref);
>>> +			return n;
>>> +		}
>>> +	}
>>> +	n = kzalloc(sizeof(*n), GFP_KERNEL);
>>> +	if (!n)
>>> +		goto unlock;
>>> +	mutex_init(&n->lock);
>>> +	BLOCKING_INIT_NOTIFIER_HEAD(&n->notifiers);
>>> +	kref_init(&n->kref);
>>
>> +	n->dev = dev;
>>
>> Currently n->dev is never set, so every caller of this function gets its
>> own hdmi_notifier.
>
> Oops! Well, I did say it was compile-tested only :-)
>
>>
>>> +	list_add_tail(&n->head, &hdmi_notifiers);
>>> +unlock:
>>> +	mutex_unlock(&hdmi_notifiers_lock);
>>> +	return n;
>>> +}
>>> +EXPORT_SYMBOL_GPL(hdmi_notifier_get);
>>> +
>>> +static void hdmi_notifier_release(struct kref *kref)
>>> +{
>>> +	struct hdmi_notifier *n =
>>> +		container_of(kref, struct hdmi_notifier, kref);
>>> +

I also forgot to remove this notifier from the global list.

I've updated my git branch to fix this.

	Hans
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Hans Verkuil Dec. 1, 2016, 10:09 a.m. UTC | #4 
On 11/14/16 16:22, Hans Verkuil wrote:
> From: Hans Verkuil <hans.verkuil@cisco.com>
>
> Add support for HDMI hotplug and EDID notifiers, which is used to convey
> information from HDMI drivers to their CEC and audio counterparts.

I realized that the name 'HDMI notifier' isn't the best: the same mechanism
can be used with e.g. DisplayPort as well.

What would be a good alternative name?

"Video Notifier"?

Any objections to that? Or suggestions for a better name?

Regards,

	Hans

>
> Based on an earlier version from Russell King:
>
> https://patchwork.kernel.org/patch/9277043/
>
> The hdmi_notifier is a reference counted object containing the HDMI state
> of an HDMI device.
>
> When a new notifier is registered the current state will be reported to
> that notifier at registration time.
>
> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
> ---
>  drivers/video/Kconfig         |   3 +
>  drivers/video/Makefile        |   1 +
>  drivers/video/hdmi-notifier.c | 136 ++++++++++++++++++++++++++++++++++++++++++
>  include/linux/hdmi-notifier.h |  43 +++++++++++++
>  4 files changed, 183 insertions(+)
>  create mode 100644 drivers/video/hdmi-notifier.c
>  create mode 100644 include/linux/hdmi-notifier.h
>
> diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
> index 3c20af9..1ee7b9f 100644
> --- a/drivers/video/Kconfig
> +++ b/drivers/video/Kconfig
> @@ -36,6 +36,9 @@ config VIDEOMODE_HELPERS
>  config HDMI
>  	bool
>
> +config HDMI_NOTIFIERS
> +	bool
> +
>  if VT
>  	source "drivers/video/console/Kconfig"
>  endif
> diff --git a/drivers/video/Makefile b/drivers/video/Makefile
> index 9ad3c17..65f5649 100644
> --- a/drivers/video/Makefile
> +++ b/drivers/video/Makefile
> @@ -1,5 +1,6 @@
>  obj-$(CONFIG_VGASTATE)            += vgastate.o
>  obj-$(CONFIG_HDMI)                += hdmi.o
> +obj-$(CONFIG_HDMI_NOTIFIERS)      += hdmi-notifier.o
>
>  obj-$(CONFIG_VT)		  += console/
>  obj-$(CONFIG_LOGO)		  += logo/
> diff --git a/drivers/video/hdmi-notifier.c b/drivers/video/hdmi-notifier.c
> new file mode 100644
> index 0000000..c2a4f1b
> --- /dev/null
> +++ b/drivers/video/hdmi-notifier.c
> @@ -0,0 +1,136 @@
> +#include <linux/export.h>
> +#include <linux/hdmi-notifier.h>
> +#include <linux/string.h>
> +#include <linux/slab.h>
> +#include <linux/list.h>
> +
> +struct hdmi_notifiers {
> +	struct list_head head;
> +	struct device *dev;
> +	struct hdmi_notifier *n;
> +};
> +
> +static LIST_HEAD(hdmi_notifiers);
> +static DEFINE_MUTEX(hdmi_notifiers_lock);
> +
> +struct hdmi_notifier *hdmi_notifier_get(struct device *dev)
> +{
> +	struct hdmi_notifier *n;
> +
> +	mutex_lock(&hdmi_notifiers_lock);
> +	list_for_each_entry(n, &hdmi_notifiers, head) {
> +		if (n->dev == dev) {
> +			mutex_unlock(&hdmi_notifiers_lock);
> +			kref_get(&n->kref);
> +			return n;
> +		}
> +	}
> +	n = kzalloc(sizeof(*n), GFP_KERNEL);
> +	if (!n)
> +		goto unlock;
> +	mutex_init(&n->lock);
> +	BLOCKING_INIT_NOTIFIER_HEAD(&n->notifiers);
> +	kref_init(&n->kref);
> +	list_add_tail(&n->head, &hdmi_notifiers);
> +unlock:
> +	mutex_unlock(&hdmi_notifiers_lock);
> +	return n;
> +}
> +EXPORT_SYMBOL_GPL(hdmi_notifier_get);
> +
> +static void hdmi_notifier_release(struct kref *kref)
> +{
> +	struct hdmi_notifier *n =
> +		container_of(kref, struct hdmi_notifier, kref);
> +
> +	kfree(n->edid);
> +	kfree(n);
> +}
> +
> +void hdmi_notifier_put(struct hdmi_notifier *n)
> +{
> +	kref_put(&n->kref, hdmi_notifier_release);
> +}
> +EXPORT_SYMBOL_GPL(hdmi_notifier_put);
> +
> +int hdmi_notifier_register(struct hdmi_notifier *n, struct notifier_block *nb)
> +{
> +	int ret = blocking_notifier_chain_register(&n->notifiers, nb);
> +
> +	if (ret)
> +		return ret;
> +	kref_get(&n->kref);
> +	mutex_lock(&n->lock);
> +	if (n->connected) {
> +		blocking_notifier_call_chain(&n->notifiers, HDMI_CONNECTED, n);
> +		if (n->edid_size)
> +			blocking_notifier_call_chain(&n->notifiers, HDMI_NEW_EDID, n);
> +		if (n->has_eld)
> +			blocking_notifier_call_chain(&n->notifiers, HDMI_NEW_ELD, n);
> +	}
> +	mutex_unlock(&n->lock);
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(hdmi_notifier_register);
> +
> +int hdmi_notifier_unregister(struct hdmi_notifier *n, struct notifier_block *nb)
> +{
> +	int ret = blocking_notifier_chain_unregister(&n->notifiers, nb);
> +
> +	if (ret == 0)
> +		hdmi_notifier_put(n);
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(hdmi_notifier_unregister);
> +
> +void hdmi_event_connect(struct hdmi_notifier *n)
> +{
> +	mutex_lock(&n->lock);
> +	n->connected = true;
> +	blocking_notifier_call_chain(&n->notifiers, HDMI_CONNECTED, n);
> +	mutex_unlock(&n->lock);
> +}
> +EXPORT_SYMBOL_GPL(hdmi_event_connect);
> +
> +void hdmi_event_disconnect(struct hdmi_notifier *n)
> +{
> +	mutex_lock(&n->lock);
> +	n->connected = false;
> +	n->has_eld = false;
> +	n->edid_size = 0;
> +	blocking_notifier_call_chain(&n->notifiers, HDMI_DISCONNECTED, n);
> +	mutex_unlock(&n->lock);
> +}
> +EXPORT_SYMBOL_GPL(hdmi_event_disconnect);
> +
> +int hdmi_event_new_edid(struct hdmi_notifier *n, const void *edid, size_t size)
> +{
> +	mutex_lock(&n->lock);
> +	if (n->edid_allocated_size < size) {
> +		void *p = kmalloc(size, GFP_KERNEL);
> +
> +		if (p == NULL) {
> +			mutex_unlock(&n->lock);
> +			return -ENOMEM;
> +		}
> +		kfree(n->edid);
> +		n->edid = p;
> +		n->edid_allocated_size = size;
> +	}
> +	memcpy(n->edid, edid, size);
> +	n->edid_size = size;
> +	blocking_notifier_call_chain(&n->notifiers, HDMI_NEW_EDID, n);
> +	mutex_unlock(&n->lock);
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(hdmi_event_new_edid);
> +
> +void hdmi_event_new_eld(struct hdmi_notifier *n, const u8 eld[128])
> +{
> +	mutex_lock(&n->lock);
> +	memcpy(n->eld, eld, sizeof(n->eld));
> +	n->has_eld = true;
> +	blocking_notifier_call_chain(&n->notifiers, HDMI_NEW_ELD, n);
> +	mutex_unlock(&n->lock);
> +}
> +EXPORT_SYMBOL_GPL(hdmi_event_new_eld);
> diff --git a/include/linux/hdmi-notifier.h b/include/linux/hdmi-notifier.h
> new file mode 100644
> index 0000000..f7fc405
> --- /dev/null
> +++ b/include/linux/hdmi-notifier.h
> @@ -0,0 +1,43 @@
> +#ifndef LINUX_HDMI_NOTIFIER_H
> +#define LINUX_HDMI_NOTIFIER_H
> +
> +#include <linux/types.h>
> +#include <linux/notifier.h>
> +#include <linux/kref.h>
> +
> +enum {
> +	HDMI_CONNECTED,
> +	HDMI_DISCONNECTED,
> +	HDMI_NEW_EDID,
> +	HDMI_NEW_ELD,
> +};
> +
> +struct device;
> +
> +struct hdmi_notifier {
> +	struct mutex lock;
> +	struct list_head head;
> +	struct kref kref;
> +	struct blocking_notifier_head notifiers;
> +	struct device *dev;
> +
> +	/* Current state */
> +	bool connected;
> +	bool has_eld;
> +	unsigned char eld[128];
> +	void *edid;
> +	size_t edid_size;
> +	size_t edid_allocated_size;
> +};
> +
> +struct hdmi_notifier *hdmi_notifier_get(struct device *dev);
> +void hdmi_notifier_put(struct hdmi_notifier *n);
> +int hdmi_notifier_register(struct hdmi_notifier *n, struct notifier_block *nb);
> +int hdmi_notifier_unregister(struct hdmi_notifier *n, struct notifier_block *nb);
> +
> +void hdmi_event_connect(struct hdmi_notifier *n);
> +void hdmi_event_disconnect(struct hdmi_notifier *n);
> +int hdmi_event_new_edid(struct hdmi_notifier *n, const void *edid, size_t size);
> +void hdmi_event_new_eld(struct hdmi_notifier *n, const u8 eld[128]);
> +
> +#endif
>
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diff mbox

Patch

diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index 3c20af9..1ee7b9f 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -36,6 +36,9 @@  config VIDEOMODE_HELPERS
 config HDMI
 	bool
 
+config HDMI_NOTIFIERS
+	bool
+
 if VT
 	source "drivers/video/console/Kconfig"
 endif
diff --git a/drivers/video/Makefile b/drivers/video/Makefile
index 9ad3c17..65f5649 100644
--- a/drivers/video/Makefile
+++ b/drivers/video/Makefile
@@ -1,5 +1,6 @@ 
 obj-$(CONFIG_VGASTATE)            += vgastate.o
 obj-$(CONFIG_HDMI)                += hdmi.o
+obj-$(CONFIG_HDMI_NOTIFIERS)      += hdmi-notifier.o
 
 obj-$(CONFIG_VT)		  += console/
 obj-$(CONFIG_LOGO)		  += logo/
diff --git a/drivers/video/hdmi-notifier.c b/drivers/video/hdmi-notifier.c
new file mode 100644
index 0000000..c2a4f1b
--- /dev/null
+++ b/drivers/video/hdmi-notifier.c
@@ -0,0 +1,136 @@ 
+#include <linux/export.h>
+#include <linux/hdmi-notifier.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+
+struct hdmi_notifiers {
+	struct list_head head;
+	struct device *dev;
+	struct hdmi_notifier *n;
+};
+
+static LIST_HEAD(hdmi_notifiers);
+static DEFINE_MUTEX(hdmi_notifiers_lock);
+
+struct hdmi_notifier *hdmi_notifier_get(struct device *dev)
+{
+	struct hdmi_notifier *n;
+
+	mutex_lock(&hdmi_notifiers_lock);
+	list_for_each_entry(n, &hdmi_notifiers, head) {
+		if (n->dev == dev) {
+			mutex_unlock(&hdmi_notifiers_lock);
+			kref_get(&n->kref);
+			return n;
+		}
+	}
+	n = kzalloc(sizeof(*n), GFP_KERNEL);
+	if (!n)
+		goto unlock;
+	mutex_init(&n->lock);
+	BLOCKING_INIT_NOTIFIER_HEAD(&n->notifiers);
+	kref_init(&n->kref);
+	list_add_tail(&n->head, &hdmi_notifiers);
+unlock:
+	mutex_unlock(&hdmi_notifiers_lock);
+	return n;
+}
+EXPORT_SYMBOL_GPL(hdmi_notifier_get);
+
+static void hdmi_notifier_release(struct kref *kref)
+{
+	struct hdmi_notifier *n =
+		container_of(kref, struct hdmi_notifier, kref);
+
+	kfree(n->edid);
+	kfree(n);
+}
+
+void hdmi_notifier_put(struct hdmi_notifier *n)
+{
+	kref_put(&n->kref, hdmi_notifier_release);
+}
+EXPORT_SYMBOL_GPL(hdmi_notifier_put);
+
+int hdmi_notifier_register(struct hdmi_notifier *n, struct notifier_block *nb)
+{
+	int ret = blocking_notifier_chain_register(&n->notifiers, nb);
+
+	if (ret)
+		return ret;
+	kref_get(&n->kref);
+	mutex_lock(&n->lock);
+	if (n->connected) {
+		blocking_notifier_call_chain(&n->notifiers, HDMI_CONNECTED, n);
+		if (n->edid_size)
+			blocking_notifier_call_chain(&n->notifiers, HDMI_NEW_EDID, n);
+		if (n->has_eld)
+			blocking_notifier_call_chain(&n->notifiers, HDMI_NEW_ELD, n);
+	}
+	mutex_unlock(&n->lock);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(hdmi_notifier_register);
+
+int hdmi_notifier_unregister(struct hdmi_notifier *n, struct notifier_block *nb)
+{
+	int ret = blocking_notifier_chain_unregister(&n->notifiers, nb);
+
+	if (ret == 0)
+		hdmi_notifier_put(n);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(hdmi_notifier_unregister);
+
+void hdmi_event_connect(struct hdmi_notifier *n)
+{
+	mutex_lock(&n->lock);
+	n->connected = true;
+	blocking_notifier_call_chain(&n->notifiers, HDMI_CONNECTED, n);
+	mutex_unlock(&n->lock);
+}
+EXPORT_SYMBOL_GPL(hdmi_event_connect);
+
+void hdmi_event_disconnect(struct hdmi_notifier *n)
+{
+	mutex_lock(&n->lock);
+	n->connected = false;
+	n->has_eld = false;
+	n->edid_size = 0;
+	blocking_notifier_call_chain(&n->notifiers, HDMI_DISCONNECTED, n);
+	mutex_unlock(&n->lock);
+}
+EXPORT_SYMBOL_GPL(hdmi_event_disconnect);
+
+int hdmi_event_new_edid(struct hdmi_notifier *n, const void *edid, size_t size)
+{
+	mutex_lock(&n->lock);
+	if (n->edid_allocated_size < size) {
+		void *p = kmalloc(size, GFP_KERNEL);
+
+		if (p == NULL) {
+			mutex_unlock(&n->lock);
+			return -ENOMEM;
+		}
+		kfree(n->edid);
+		n->edid = p;
+		n->edid_allocated_size = size;
+	}
+	memcpy(n->edid, edid, size);
+	n->edid_size = size;
+	blocking_notifier_call_chain(&n->notifiers, HDMI_NEW_EDID, n);
+	mutex_unlock(&n->lock);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(hdmi_event_new_edid);
+
+void hdmi_event_new_eld(struct hdmi_notifier *n, const u8 eld[128])
+{
+	mutex_lock(&n->lock);
+	memcpy(n->eld, eld, sizeof(n->eld));
+	n->has_eld = true;
+	blocking_notifier_call_chain(&n->notifiers, HDMI_NEW_ELD, n);
+	mutex_unlock(&n->lock);
+}
+EXPORT_SYMBOL_GPL(hdmi_event_new_eld);
diff --git a/include/linux/hdmi-notifier.h b/include/linux/hdmi-notifier.h
new file mode 100644
index 0000000..f7fc405
--- /dev/null
+++ b/include/linux/hdmi-notifier.h
@@ -0,0 +1,43 @@ 
+#ifndef LINUX_HDMI_NOTIFIER_H
+#define LINUX_HDMI_NOTIFIER_H
+
+#include <linux/types.h>
+#include <linux/notifier.h>
+#include <linux/kref.h>
+
+enum {
+	HDMI_CONNECTED,
+	HDMI_DISCONNECTED,
+	HDMI_NEW_EDID,
+	HDMI_NEW_ELD,
+};
+
+struct device;
+
+struct hdmi_notifier {
+	struct mutex lock;
+	struct list_head head;
+	struct kref kref;
+	struct blocking_notifier_head notifiers;
+	struct device *dev;
+
+	/* Current state */
+	bool connected;
+	bool has_eld;
+	unsigned char eld[128];
+	void *edid;
+	size_t edid_size;
+	size_t edid_allocated_size;
+};
+
+struct hdmi_notifier *hdmi_notifier_get(struct device *dev);
+void hdmi_notifier_put(struct hdmi_notifier *n);
+int hdmi_notifier_register(struct hdmi_notifier *n, struct notifier_block *nb);
+int hdmi_notifier_unregister(struct hdmi_notifier *n, struct notifier_block *nb);
+
+void hdmi_event_connect(struct hdmi_notifier *n);
+void hdmi_event_disconnect(struct hdmi_notifier *n);
+int hdmi_event_new_edid(struct hdmi_notifier *n, const void *edid, size_t size);
+void hdmi_event_new_eld(struct hdmi_notifier *n, const u8 eld[128]);
+
+#endif