From: Hans Verkuil <hans.verkuil@xxxxxxxxx> Add support for video hotplug detect and EDID/ELD notifiers, which is used to convey information from video drivers to their CEC and audio counterparts. Based on an earlier version from Russell King: https://patchwork.kernel.org/patch/9277043/ The hpd_notifier is a reference counted object containing the HPD/EDID/ELD state of a video 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@xxxxxxxxx> Tested-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> --- drivers/video/Kconfig | 3 + drivers/video/Makefile | 1 + drivers/video/hpd-notifier.c | 134 +++++++++++++++++++++++++++++++++++++++++++ include/linux/hpd-notifier.h | 109 +++++++++++++++++++++++++++++++++++ 4 files changed, 247 insertions(+) create mode 100644 drivers/video/hpd-notifier.c create mode 100644 include/linux/hpd-notifier.h diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig index 3c20af999893..a3a58d8481e9 100644 --- a/drivers/video/Kconfig +++ b/drivers/video/Kconfig @@ -36,6 +36,9 @@ config VIDEOMODE_HELPERS config HDMI bool +config HPD_NOTIFIER + bool + if VT source "drivers/video/console/Kconfig" endif diff --git a/drivers/video/Makefile b/drivers/video/Makefile index 9ad3c17d6456..2697ae5c4166 100644 --- a/drivers/video/Makefile +++ b/drivers/video/Makefile @@ -1,5 +1,6 @@ obj-$(CONFIG_VGASTATE) += vgastate.o obj-$(CONFIG_HDMI) += hdmi.o +obj-$(CONFIG_HPD_NOTIFIER) += hpd-notifier.o obj-$(CONFIG_VT) += console/ obj-$(CONFIG_LOGO) += logo/ diff --git a/drivers/video/hpd-notifier.c b/drivers/video/hpd-notifier.c new file mode 100644 index 000000000000..971e823ead00 --- /dev/null +++ b/drivers/video/hpd-notifier.c @@ -0,0 +1,134 @@ +#include <linux/export.h> +#include <linux/hpd-notifier.h> +#include <linux/string.h> +#include <linux/slab.h> +#include <linux/list.h> + +static LIST_HEAD(hpd_notifiers); +static DEFINE_MUTEX(hpd_notifiers_lock); + +struct hpd_notifier *hpd_notifier_get(struct device *dev) +{ + struct hpd_notifier *n; + + mutex_lock(&hpd_notifiers_lock); + list_for_each_entry(n, &hpd_notifiers, head) { + if (n->dev == dev) { + mutex_unlock(&hpd_notifiers_lock); + kref_get(&n->kref); + return n; + } + } + n = kzalloc(sizeof(*n), GFP_KERNEL); + if (!n) + goto unlock; + n->dev = dev; + mutex_init(&n->lock); + BLOCKING_INIT_NOTIFIER_HEAD(&n->notifiers); + kref_init(&n->kref); + list_add_tail(&n->head, &hpd_notifiers); +unlock: + mutex_unlock(&hpd_notifiers_lock); + return n; +} +EXPORT_SYMBOL_GPL(hpd_notifier_get); + +static void hpd_notifier_release(struct kref *kref) +{ + struct hpd_notifier *n = + container_of(kref, struct hpd_notifier, kref); + + list_del(&n->head); + kfree(n->edid); + kfree(n); +} + +void hpd_notifier_put(struct hpd_notifier *n) +{ + mutex_lock(&hpd_notifiers_lock); + kref_put(&n->kref, hpd_notifier_release); + mutex_unlock(&hpd_notifiers_lock); +} +EXPORT_SYMBOL_GPL(hpd_notifier_put); + +int hpd_notifier_register(struct hpd_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, HPD_CONNECTED, n); + if (n->edid_size) + blocking_notifier_call_chain(&n->notifiers, HPD_NEW_EDID, n); + if (n->has_eld) + blocking_notifier_call_chain(&n->notifiers, HPD_NEW_ELD, n); + } + mutex_unlock(&n->lock); + return 0; +} +EXPORT_SYMBOL_GPL(hpd_notifier_register); + +int hpd_notifier_unregister(struct hpd_notifier *n, struct notifier_block *nb) +{ + int ret = blocking_notifier_chain_unregister(&n->notifiers, nb); + + if (ret == 0) + hpd_notifier_put(n); + return ret; +} +EXPORT_SYMBOL_GPL(hpd_notifier_unregister); + +void hpd_event_connect(struct hpd_notifier *n) +{ + mutex_lock(&n->lock); + n->connected = true; + blocking_notifier_call_chain(&n->notifiers, HPD_CONNECTED, n); + mutex_unlock(&n->lock); +} +EXPORT_SYMBOL_GPL(hpd_event_connect); + +void hpd_event_disconnect(struct hpd_notifier *n) +{ + mutex_lock(&n->lock); + n->connected = false; + n->has_eld = false; + n->edid_size = 0; + blocking_notifier_call_chain(&n->notifiers, HPD_DISCONNECTED, n); + mutex_unlock(&n->lock); +} +EXPORT_SYMBOL_GPL(hpd_event_disconnect); + +int hpd_event_new_edid(struct hpd_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, HPD_NEW_EDID, n); + mutex_unlock(&n->lock); + return 0; +} +EXPORT_SYMBOL_GPL(hpd_event_new_edid); + +void hpd_event_new_eld(struct hpd_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, HPD_NEW_ELD, n); + mutex_unlock(&n->lock); +} +EXPORT_SYMBOL_GPL(hpd_event_new_eld); diff --git a/include/linux/hpd-notifier.h b/include/linux/hpd-notifier.h new file mode 100644 index 000000000000..4dcb4515d2b2 --- /dev/null +++ b/include/linux/hpd-notifier.h @@ -0,0 +1,109 @@ +/* + * hpd-notifier.h - notify interested parties of (dis)connect and EDID + * events + * + * Copyright 2016 Russell King <rmk+kernel@xxxxxxxxxxxxxxxx> + * Copyright 2016 Cisco Systems, Inc. and/or its affiliates. All rights reserved. + */ + +#ifndef LINUX_HPD_NOTIFIER_H +#define LINUX_HPD_NOTIFIER_H + +#include <linux/types.h> +#include <linux/notifier.h> +#include <linux/kref.h> + +enum { + HPD_CONNECTED, + HPD_DISCONNECTED, + HPD_NEW_EDID, + HPD_NEW_ELD, +}; + +struct device; + +struct hpd_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; +}; + +/** + * hpd_notifier_get - find or create a new hpd_notifier for the given device. + * @dev: device that sends the events. + * + * If a notifier for device @dev already exists, then increase the refcount + * and return that notifier. + * + * If it doesn't exist, then allocate a new notifier struct and return a + * pointer to that new struct. + * + * Return NULL if the memory could not be allocated. + */ +struct hpd_notifier *hpd_notifier_get(struct device *dev); + +/** + * hpd_notifier_put - decrease refcount and delete when the refcount reaches 0. + * @n: notifier + */ +void hpd_notifier_put(struct hpd_notifier *n); + +/** + * hpd_notifier_register - register the notifier with the notifier_block. + * @n: the HPD notifier + * @nb: the notifier_block + */ +int hpd_notifier_register(struct hpd_notifier *n, struct notifier_block *nb); + +/** + * hpd_notifier_unregister - unregister the notifier with the notifier_block. + * @n: the HPD notifier + * @nb: the notifier_block + */ +int hpd_notifier_unregister(struct hpd_notifier *n, struct notifier_block *nb); + +/** + * hpd_event_connect - send a connect event. + * @n: the HPD notifier + * + * Send an HPD_CONNECTED event to any registered parties. + */ +void hpd_event_connect(struct hpd_notifier *n); + +/** + * hpd_event_disconnect - send a disconnect event. + * @n: the HPD notifier + * + * Send an HPD_DISCONNECTED event to any registered parties. + */ +void hpd_event_disconnect(struct hpd_notifier *n); + +/** + * hpd_event_new_edid - send a new EDID event. + * @n: the HPD notifier + * + * Send an HPD_NEW_EDID event to any registered parties. + * This function will make a copy the EDID so it can return -ENOMEM if + * no memory could be allocated. + */ +int hpd_event_new_edid(struct hpd_notifier *n, const void *edid, size_t size); + +/** + * hpd_event_new_eld - send a new ELD event. + * @n: the HPD notifier + * + * Send an HPD_NEW_ELD event to any registered parties. + */ +void hpd_event_new_eld(struct hpd_notifier *n, const u8 eld[128]); + +#endif -- 2.11.0 -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
