starnix_modules_touch_power_policy/
lib.rs

1// Copyright 2024 The Fuchsia Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5use starnix_core::device::DeviceOps;
6use starnix_core::task::dynamic_thread_spawner::SpawnRequestBuilder;
7use starnix_core::task::{CurrentTask, Kernel, LockupDetectorReceiver};
8use starnix_core::vfs::buffers::{InputBuffer, OutputBuffer};
9use starnix_core::vfs::{
10    CloseFreeSafe, FileObject, FileOps, NamespaceNode, fileops_impl_nonseekable,
11    fileops_impl_noop_sync,
12};
13use starnix_logging::{log_error, log_info};
14use starnix_sync::{FileOpsCore, LockDepMutex, LockEqualOrBefore, Locked, TerminalLock, Unlocked};
15use starnix_uapi::device_id::DeviceId;
16use starnix_uapi::error;
17use starnix_uapi::errors::Errno;
18use starnix_uapi::open_flags::OpenFlags;
19use std::sync::Arc;
20use std::sync::mpsc::Sender;
21use zerocopy::IntoBytes;
22
23#[derive(Clone)]
24pub struct TouchPowerPolicyDevice {
25    touch_power_file: Arc<TouchPowerPolicyFile>,
26}
27
28impl TouchPowerPolicyDevice {
29    pub fn new(touch_standby_sender: Sender<bool>) -> Self {
30        TouchPowerPolicyDevice { touch_power_file: TouchPowerPolicyFile::new(touch_standby_sender) }
31    }
32
33    pub fn register<L>(self, locked: &mut Locked<L>, system_task: &CurrentTask)
34    where
35        L: LockEqualOrBefore<FileOpsCore>,
36    {
37        let kernel = system_task.kernel();
38        let registry = &kernel.device_registry;
39        registry
40            .register_dyn_device(
41                locked,
42                system_task,
43                "touch_standby".into(),
44                registry.objects.starnix_class(),
45                self,
46            )
47            .expect("can register touch_standby device");
48    }
49
50    pub fn start_relay(
51        &self,
52        kernel: &Kernel,
53        touch_standby_receiver: LockupDetectorReceiver<bool>,
54    ) {
55        let slf = self.clone();
56        let closure = move |_lock_context: &mut Locked<Unlocked>, _current_task: &CurrentTask| {
57            let mut prev_enabled = true;
58            while let Ok(touch_enabled) = touch_standby_receiver.recv() {
59                if touch_enabled != prev_enabled {
60                    slf.notify_standby_state_changed(touch_enabled);
61                }
62                prev_enabled = touch_enabled;
63            }
64            log_error!("touch_standby relay was terminated unexpectedly.");
65        };
66        let req = SpawnRequestBuilder::new()
67            .with_debug_name("touch-power-policy-relay")
68            .with_sync_closure(closure)
69            .build();
70        kernel.kthreads.spawner().spawn_from_request(req);
71    }
72
73    fn notify_standby_state_changed(&self, touch_enabled: bool) {
74        // TODO(b/341142285): notify input pipeline that touch_standby state has changed
75        log_info!("touch enabled: {:?}", touch_enabled);
76    }
77}
78
79impl DeviceOps for TouchPowerPolicyDevice {
80    fn open(
81        &self,
82        _locked: &mut Locked<FileOpsCore>,
83        _current_task: &CurrentTask,
84        _devt: DeviceId,
85        _node: &NamespaceNode,
86        _flags: OpenFlags,
87    ) -> Result<Box<dyn FileOps>, Errno> {
88        let touch_policy_file = self.touch_power_file.clone();
89        Ok(Box::new(touch_policy_file))
90    }
91}
92
93pub struct TouchPowerPolicyFile {
94    // When false, Input Pipeline suspends processing of all touch events.
95    touch_enabled: LockDepMutex<bool, TerminalLock>,
96    // Sender used to send changes to `touch_standby` to the device relay
97    touch_standby_sender: Sender<bool>,
98}
99
100impl TouchPowerPolicyFile {
101    pub fn new(touch_standby_sender: Sender<bool>) -> Arc<Self> {
102        Arc::new(TouchPowerPolicyFile {
103            touch_enabled: LockDepMutex::new(true),
104            touch_standby_sender,
105        })
106    }
107}
108
109/// `TouchPowerPolicyFile` doesn't implement the `close` method.
110impl CloseFreeSafe for TouchPowerPolicyFile {}
111impl FileOps for TouchPowerPolicyFile {
112    fileops_impl_nonseekable!();
113    fileops_impl_noop_sync!();
114
115    fn read(
116        &self,
117        _locked: &mut Locked<FileOpsCore>,
118        _file: &FileObject,
119        _current_task: &CurrentTask,
120        offset: usize,
121        data: &mut dyn OutputBuffer,
122    ) -> Result<usize, Errno> {
123        debug_assert!(offset == 0);
124        let touch_enabled = self.touch_enabled.lock().to_owned();
125        data.write_all(touch_enabled.as_bytes())
126    }
127
128    fn write(
129        &self,
130        _locked: &mut Locked<FileOpsCore>,
131        _file: &FileObject,
132        _current_task: &CurrentTask,
133        _offset: usize,
134        data: &mut dyn InputBuffer,
135    ) -> Result<usize, Errno> {
136        let content = data.read_all()?;
137        let sys_touch_standby = match &*content {
138            b"0" | b"0\n" => false,
139            b"1" | b"1\n" => true,
140            _ => {
141                log_error!("Invalid touch_standby value - must be 0 or 1");
142                return error!(EINVAL);
143            }
144        };
145        *self.touch_enabled.lock() = sys_touch_standby;
146        if let Err(e) = self.touch_standby_sender.send(sys_touch_standby) {
147            log_error!("unable to send recent touch_standby state to device relay: {:?}", e);
148        }
149        Ok(content.len())
150    }
151}
starnix_modules_touch_power_policy/lib.rs

starnix_modules_touch_power_policy/
lib.rs
