472 lines
14 KiB
C
472 lines
14 KiB
C
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// SPDX-License-Identifier: MIT
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/*
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* Copyright (C) 2020 - 2021 Red Hat, Inc.
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*
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* Authors:
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* Hans de Goede <hdegoede@redhat.com>
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*/
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#include <linux/device.h>
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#include <linux/kernel.h>
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#include <linux/list.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/slab.h>
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#include <drm/drm_privacy_screen_machine.h>
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#include <drm/drm_privacy_screen_consumer.h>
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#include <drm/drm_privacy_screen_driver.h>
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#include "drm_internal.h"
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/**
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* DOC: overview
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*
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* This class allows non KMS drivers, from e.g. drivers/platform/x86 to
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* register a privacy-screen device, which the KMS drivers can then use
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* to implement the standard privacy-screen properties, see
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* :ref:`Standard Connector Properties<standard_connector_properties>`.
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*
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* KMS drivers using a privacy-screen class device are advised to use the
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* drm_connector_attach_privacy_screen_provider() and
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* drm_connector_update_privacy_screen() helpers for dealing with this.
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*/
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#define to_drm_privacy_screen(dev) \
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container_of(dev, struct drm_privacy_screen, dev)
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static DEFINE_MUTEX(drm_privacy_screen_lookup_lock);
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static LIST_HEAD(drm_privacy_screen_lookup_list);
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static DEFINE_MUTEX(drm_privacy_screen_devs_lock);
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static LIST_HEAD(drm_privacy_screen_devs);
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/*** drm_privacy_screen_machine.h functions ***/
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/**
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* drm_privacy_screen_lookup_add - add an entry to the static privacy-screen
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* lookup list
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* @lookup: lookup list entry to add
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*
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* Add an entry to the static privacy-screen lookup list. Note the
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* &struct list_head which is part of the &struct drm_privacy_screen_lookup
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* gets added to a list owned by the privacy-screen core. So the passed in
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* &struct drm_privacy_screen_lookup must not be free-ed until it is removed
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* from the lookup list by calling drm_privacy_screen_lookup_remove().
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*/
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void drm_privacy_screen_lookup_add(struct drm_privacy_screen_lookup *lookup)
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{
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mutex_lock(&drm_privacy_screen_lookup_lock);
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list_add(&lookup->list, &drm_privacy_screen_lookup_list);
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mutex_unlock(&drm_privacy_screen_lookup_lock);
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}
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EXPORT_SYMBOL(drm_privacy_screen_lookup_add);
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/**
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* drm_privacy_screen_lookup_remove - remove an entry to the static
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* privacy-screen lookup list
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* @lookup: lookup list entry to remove
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*
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* Remove an entry previously added with drm_privacy_screen_lookup_add()
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* from the static privacy-screen lookup list.
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*/
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void drm_privacy_screen_lookup_remove(struct drm_privacy_screen_lookup *lookup)
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{
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mutex_lock(&drm_privacy_screen_lookup_lock);
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list_del(&lookup->list);
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mutex_unlock(&drm_privacy_screen_lookup_lock);
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}
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EXPORT_SYMBOL(drm_privacy_screen_lookup_remove);
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/*** drm_privacy_screen_consumer.h functions ***/
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static struct drm_privacy_screen *drm_privacy_screen_get_by_name(
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const char *name)
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{
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struct drm_privacy_screen *priv;
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struct device *dev = NULL;
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mutex_lock(&drm_privacy_screen_devs_lock);
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list_for_each_entry(priv, &drm_privacy_screen_devs, list) {
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if (strcmp(dev_name(&priv->dev), name) == 0) {
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dev = get_device(&priv->dev);
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break;
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}
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}
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mutex_unlock(&drm_privacy_screen_devs_lock);
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return dev ? to_drm_privacy_screen(dev) : NULL;
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}
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/**
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* drm_privacy_screen_get - get a privacy-screen provider
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* @dev: consumer-device for which to get a privacy-screen provider
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* @con_id: (video)connector name for which to get a privacy-screen provider
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*
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* Get a privacy-screen provider for a privacy-screen attached to the
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* display described by the @dev and @con_id parameters.
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*
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* Return:
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* * A pointer to a &struct drm_privacy_screen on success.
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* * ERR_PTR(-ENODEV) if no matching privacy-screen is found
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* * ERR_PTR(-EPROBE_DEFER) if there is a matching privacy-screen,
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* but it has not been registered yet.
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*/
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struct drm_privacy_screen *drm_privacy_screen_get(struct device *dev,
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const char *con_id)
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{
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const char *dev_id = dev ? dev_name(dev) : NULL;
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struct drm_privacy_screen_lookup *l;
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struct drm_privacy_screen *priv;
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const char *provider = NULL;
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int match, best = -1;
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/*
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* For now we only support using a static lookup table, which is
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* populated by the drm_privacy_screen_arch_init() call. This should
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* be extended with device-tree / fw_node lookup when support is added
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* for device-tree using hardware with a privacy-screen.
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*
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* The lookup algorithm was shamelessly taken from the clock
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* framework:
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*
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* We do slightly fuzzy matching here:
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* An entry with a NULL ID is assumed to be a wildcard.
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* If an entry has a device ID, it must match
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* If an entry has a connection ID, it must match
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* Then we take the most specific entry - with the following order
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* of precedence: dev+con > dev only > con only.
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*/
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mutex_lock(&drm_privacy_screen_lookup_lock);
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list_for_each_entry(l, &drm_privacy_screen_lookup_list, list) {
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match = 0;
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if (l->dev_id) {
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if (!dev_id || strcmp(l->dev_id, dev_id))
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continue;
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match += 2;
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}
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if (l->con_id) {
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if (!con_id || strcmp(l->con_id, con_id))
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continue;
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match += 1;
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}
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if (match > best) {
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provider = l->provider;
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best = match;
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}
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}
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mutex_unlock(&drm_privacy_screen_lookup_lock);
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if (!provider)
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return ERR_PTR(-ENODEV);
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priv = drm_privacy_screen_get_by_name(provider);
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if (!priv)
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return ERR_PTR(-EPROBE_DEFER);
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return priv;
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}
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EXPORT_SYMBOL(drm_privacy_screen_get);
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/**
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* drm_privacy_screen_put - release a privacy-screen reference
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* @priv: privacy screen reference to release
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*
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* Release a privacy-screen provider reference gotten through
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* drm_privacy_screen_get(). May be called with a NULL or ERR_PTR,
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* in which case it is a no-op.
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*/
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void drm_privacy_screen_put(struct drm_privacy_screen *priv)
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{
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if (IS_ERR_OR_NULL(priv))
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return;
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put_device(&priv->dev);
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}
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EXPORT_SYMBOL(drm_privacy_screen_put);
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/**
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* drm_privacy_screen_set_sw_state - set a privacy-screen's sw-state
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* @priv: privacy screen to set the sw-state for
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* @sw_state: new sw-state value to set
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*
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* Set the sw-state of a privacy screen. If the privacy-screen is not
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* in a locked hw-state, then the actual and hw-state of the privacy-screen
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* will be immediately updated to the new value. If the privacy-screen is
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* in a locked hw-state, then the new sw-state will be remembered as the
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* requested state to put the privacy-screen in when it becomes unlocked.
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*
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* Return: 0 on success, negative error code on failure.
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*/
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int drm_privacy_screen_set_sw_state(struct drm_privacy_screen *priv,
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enum drm_privacy_screen_status sw_state)
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{
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int ret = 0;
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mutex_lock(&priv->lock);
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if (!priv->ops) {
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ret = -ENODEV;
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goto out;
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}
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/*
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* As per the DRM connector properties documentation, setting the
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* sw_state while the hw_state is locked is allowed. In this case
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* it is a no-op other then storing the new sw_state so that it
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* can be honored when the state gets unlocked.
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* Also skip the set if the hw already is in the desired state.
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*/
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if (priv->hw_state >= PRIVACY_SCREEN_DISABLED_LOCKED ||
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priv->hw_state == sw_state) {
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priv->sw_state = sw_state;
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goto out;
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}
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ret = priv->ops->set_sw_state(priv, sw_state);
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out:
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mutex_unlock(&priv->lock);
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return ret;
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}
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EXPORT_SYMBOL(drm_privacy_screen_set_sw_state);
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/**
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* drm_privacy_screen_get_state - get privacy-screen's current state
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* @priv: privacy screen to get the state for
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* @sw_state_ret: address where to store the privacy-screens current sw-state
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* @hw_state_ret: address where to store the privacy-screens current hw-state
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*
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* Get the current state of a privacy-screen, both the sw-state and the
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* hw-state.
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*/
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void drm_privacy_screen_get_state(struct drm_privacy_screen *priv,
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enum drm_privacy_screen_status *sw_state_ret,
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enum drm_privacy_screen_status *hw_state_ret)
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{
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mutex_lock(&priv->lock);
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*sw_state_ret = priv->sw_state;
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*hw_state_ret = priv->hw_state;
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mutex_unlock(&priv->lock);
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}
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EXPORT_SYMBOL(drm_privacy_screen_get_state);
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/**
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* drm_privacy_screen_register_notifier - register a notifier
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* @priv: Privacy screen to register the notifier with
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* @nb: Notifier-block for the notifier to register
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*
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* Register a notifier with the privacy-screen to be notified of changes made
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* to the privacy-screen state from outside of the privacy-screen class.
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* E.g. the state may be changed by the hardware itself in response to a
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* hotkey press.
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*
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* The notifier is called with no locks held. The new hw_state and sw_state
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* can be retrieved using the drm_privacy_screen_get_state() function.
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* A pointer to the drm_privacy_screen's struct is passed as the ``void *data``
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* argument of the notifier_block's notifier_call.
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*
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* The notifier will NOT be called when changes are made through
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* drm_privacy_screen_set_sw_state(). It is only called for external changes.
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*
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* Return: 0 on success, negative error code on failure.
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*/
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int drm_privacy_screen_register_notifier(struct drm_privacy_screen *priv,
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struct notifier_block *nb)
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{
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return blocking_notifier_chain_register(&priv->notifier_head, nb);
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}
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EXPORT_SYMBOL(drm_privacy_screen_register_notifier);
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/**
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* drm_privacy_screen_unregister_notifier - unregister a notifier
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* @priv: Privacy screen to register the notifier with
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* @nb: Notifier-block for the notifier to register
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*
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* Unregister a notifier registered with drm_privacy_screen_register_notifier().
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*
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* Return: 0 on success, negative error code on failure.
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*/
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int drm_privacy_screen_unregister_notifier(struct drm_privacy_screen *priv,
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struct notifier_block *nb)
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{
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return blocking_notifier_chain_unregister(&priv->notifier_head, nb);
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}
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EXPORT_SYMBOL(drm_privacy_screen_unregister_notifier);
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/*** drm_privacy_screen_driver.h functions ***/
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static ssize_t sw_state_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct drm_privacy_screen *priv = to_drm_privacy_screen(dev);
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const char * const sw_state_names[] = {
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"Disabled",
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"Enabled",
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};
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ssize_t ret;
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mutex_lock(&priv->lock);
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if (!priv->ops)
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ret = -ENODEV;
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else if (WARN_ON(priv->sw_state >= ARRAY_SIZE(sw_state_names)))
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ret = -ENXIO;
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else
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ret = sprintf(buf, "%s\n", sw_state_names[priv->sw_state]);
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mutex_unlock(&priv->lock);
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return ret;
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}
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/*
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* RO: Do not allow setting the sw_state through sysfs, this MUST be done
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* through the drm_properties on the drm_connector.
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*/
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static DEVICE_ATTR_RO(sw_state);
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static ssize_t hw_state_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct drm_privacy_screen *priv = to_drm_privacy_screen(dev);
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const char * const hw_state_names[] = {
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"Disabled",
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"Enabled",
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"Disabled, locked",
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"Enabled, locked",
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};
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ssize_t ret;
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mutex_lock(&priv->lock);
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if (!priv->ops)
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ret = -ENODEV;
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else if (WARN_ON(priv->hw_state >= ARRAY_SIZE(hw_state_names)))
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ret = -ENXIO;
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else
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ret = sprintf(buf, "%s\n", hw_state_names[priv->hw_state]);
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mutex_unlock(&priv->lock);
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return ret;
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}
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static DEVICE_ATTR_RO(hw_state);
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static struct attribute *drm_privacy_screen_attrs[] = {
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&dev_attr_sw_state.attr,
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&dev_attr_hw_state.attr,
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NULL
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};
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ATTRIBUTE_GROUPS(drm_privacy_screen);
|
||
|
|
|
||
|
|
static struct device_type drm_privacy_screen_type = {
|
||
|
|
.name = "privacy_screen",
|
||
|
|
.groups = drm_privacy_screen_groups,
|
||
|
|
};
|
||
|
|
|
||
|
|
static void drm_privacy_screen_device_release(struct device *dev)
|
||
|
|
{
|
||
|
|
struct drm_privacy_screen *priv = to_drm_privacy_screen(dev);
|
||
|
|
|
||
|
|
kfree(priv);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* drm_privacy_screen_register - register a privacy-screen
|
||
|
|
* @parent: parent-device for the privacy-screen
|
||
|
|
* @ops: &struct drm_privacy_screen_ops pointer with ops for the privacy-screen
|
||
|
|
* @data: Private data owned by the privacy screen provider
|
||
|
|
*
|
||
|
|
* Create and register a privacy-screen.
|
||
|
|
*
|
||
|
|
* Return:
|
||
|
|
* * A pointer to the created privacy-screen on success.
|
||
|
|
* * An ERR_PTR(errno) on failure.
|
||
|
|
*/
|
||
|
|
struct drm_privacy_screen *drm_privacy_screen_register(
|
||
|
|
struct device *parent, const struct drm_privacy_screen_ops *ops,
|
||
|
|
void *data)
|
||
|
|
{
|
||
|
|
struct drm_privacy_screen *priv;
|
||
|
|
int ret;
|
||
|
|
|
||
|
|
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
|
||
|
|
if (!priv)
|
||
|
|
return ERR_PTR(-ENOMEM);
|
||
|
|
|
||
|
|
mutex_init(&priv->lock);
|
||
|
|
BLOCKING_INIT_NOTIFIER_HEAD(&priv->notifier_head);
|
||
|
|
|
||
|
|
priv->dev.class = drm_class;
|
||
|
|
priv->dev.type = &drm_privacy_screen_type;
|
||
|
|
priv->dev.parent = parent;
|
||
|
|
priv->dev.release = drm_privacy_screen_device_release;
|
||
|
|
dev_set_name(&priv->dev, "privacy_screen-%s", dev_name(parent));
|
||
|
|
priv->drvdata = data;
|
||
|
|
priv->ops = ops;
|
||
|
|
|
||
|
|
priv->ops->get_hw_state(priv);
|
||
|
|
|
||
|
|
ret = device_register(&priv->dev);
|
||
|
|
if (ret) {
|
||
|
|
put_device(&priv->dev);
|
||
|
|
return ERR_PTR(ret);
|
||
|
|
}
|
||
|
|
|
||
|
|
mutex_lock(&drm_privacy_screen_devs_lock);
|
||
|
|
list_add(&priv->list, &drm_privacy_screen_devs);
|
||
|
|
mutex_unlock(&drm_privacy_screen_devs_lock);
|
||
|
|
|
||
|
|
return priv;
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL(drm_privacy_screen_register);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* drm_privacy_screen_unregister - unregister privacy-screen
|
||
|
|
* @priv: privacy-screen to unregister
|
||
|
|
*
|
||
|
|
* Unregister a privacy-screen registered with drm_privacy_screen_register().
|
||
|
|
* May be called with a NULL or ERR_PTR, in which case it is a no-op.
|
||
|
|
*/
|
||
|
|
void drm_privacy_screen_unregister(struct drm_privacy_screen *priv)
|
||
|
|
{
|
||
|
|
if (IS_ERR_OR_NULL(priv))
|
||
|
|
return;
|
||
|
|
|
||
|
|
mutex_lock(&drm_privacy_screen_devs_lock);
|
||
|
|
list_del(&priv->list);
|
||
|
|
mutex_unlock(&drm_privacy_screen_devs_lock);
|
||
|
|
|
||
|
|
mutex_lock(&priv->lock);
|
||
|
|
priv->drvdata = NULL;
|
||
|
|
priv->ops = NULL;
|
||
|
|
mutex_unlock(&priv->lock);
|
||
|
|
|
||
|
|
device_unregister(&priv->dev);
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL(drm_privacy_screen_unregister);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* drm_privacy_screen_call_notifier_chain - notify consumers of state change
|
||
|
|
* @priv: Privacy screen to register the notifier with
|
||
|
|
*
|
||
|
|
* A privacy-screen provider driver can call this functions upon external
|
||
|
|
* changes to the privacy-screen state. E.g. the state may be changed by the
|
||
|
|
* hardware itself in response to a hotkey press.
|
||
|
|
* This function must be called without holding the privacy-screen lock.
|
||
|
|
* the driver must update sw_state and hw_state to reflect the new state before
|
||
|
|
* calling this function.
|
||
|
|
* The expected behavior from the driver upon receiving an external state
|
||
|
|
* change event is: 1. Take the lock; 2. Update sw_state and hw_state;
|
||
|
|
* 3. Release the lock. 4. Call drm_privacy_screen_call_notifier_chain().
|
||
|
|
*/
|
||
|
|
void drm_privacy_screen_call_notifier_chain(struct drm_privacy_screen *priv)
|
||
|
|
{
|
||
|
|
blocking_notifier_call_chain(&priv->notifier_head, 0, priv);
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL(drm_privacy_screen_call_notifier_chain);
|