[RFCv2 PATCH 1/5] video: add HDMI state notifier support
Hans Verkuil
hverkuil at xs4all.nl
Thu Dec 1 02:09:35 PST 2016
On 11/14/16 16:22, Hans Verkuil wrote:
> From: Hans Verkuil <hans.verkuil at 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 at 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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