starnix_modules_framebuffer/
lib.rs

1// Copyright 2022 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
5#![recursion_limit = "512"]
6
7mod server;
8
9use crate::server::{FramebufferServer, init_viewport_scene, start_presentation_loop};
10use fuchsia_component::client::connect_to_protocol_sync;
11use starnix_core::device::kobject::DeviceMetadata;
12use starnix_core::device::{DeviceMode, DeviceOps};
13use starnix_core::mm::MemoryAccessorExt;
14use starnix_core::mm::memory::MemoryObject;
15use starnix_core::task::{CurrentTask, Kernel};
16use starnix_core::vfs::{
17    CloseFreeSafe, FileObject, FileOps, NamespaceNode, fileops_impl_memory, fileops_impl_noop_sync,
18};
19use starnix_logging::{log_info, log_warn, track_stub};
20use starnix_sync::{FileOpsCore, LockEqualOrBefore, Locked, Mutex, RwLock, Unlocked};
21use starnix_syscalls::{SUCCESS, SyscallArg, SyscallResult};
22use starnix_uapi::device_type::DeviceType;
23use starnix_uapi::errors::Errno;
24use starnix_uapi::open_flags::OpenFlags;
25use starnix_uapi::user_address::{MultiArchUserRef, UserAddress};
26use starnix_uapi::{
27    FB_BLANK_POWERDOWN, FB_BLANK_UNBLANK, FB_TYPE_PACKED_PIXELS, FB_VISUAL_TRUECOLOR, FBIOBLANK,
28    FBIOGET_FSCREENINFO, FBIOGET_VSCREENINFO, FBIOPUT_VSCREENINFO, errno, error, fb_bitfield,
29    fb_fix_screeninfo, fb_var_screeninfo, uapi,
30};
31use std::sync::Arc;
32use zerocopy::IntoBytes;
33use {
34    fidl_fuchsia_io as fio, fidl_fuchsia_math as fmath,
35    fidl_fuchsia_ui_composition as fuicomposition, fidl_fuchsia_ui_display_singleton as fuidisplay,
36    fidl_fuchsia_ui_views as fuiviews,
37};
38
39fn get_display_size() -> Result<fmath::SizeU, Errno> {
40    let singleton_display_info =
41        connect_to_protocol_sync::<fuidisplay::InfoMarker>().map_err(|_| errno!(ENOENT))?;
42    let metrics = singleton_display_info
43        .get_metrics(zx::MonotonicInstant::INFINITE)
44        .map_err(|_| errno!(EINVAL))?;
45    let extent_in_px =
46        metrics.extent_in_px.ok_or("Failed to get extent_in_px").map_err(|_| errno!(EINVAL))?;
47    Ok(extent_in_px)
48}
49
50#[derive(Clone, Copy, Debug, Default)]
51pub struct AspectRatio {
52    pub width: u32,
53    pub height: u32,
54}
55
56pub struct Framebuffer {
57    server: Option<Arc<FramebufferServer>>,
58    memory: Mutex<Option<Arc<MemoryObject>>>,
59    pub info: RwLock<fb_var_screeninfo>,
60    pub view_identity: Mutex<Option<fuiviews::ViewIdentityOnCreation>>,
61    pub view_bound_protocols: Mutex<Option<fuicomposition::ViewBoundProtocols>>,
62}
63
64impl Framebuffer {
65    /// Returns the current fraembuffer if one was created for this kernel.
66    pub fn get(kernel: &Kernel) -> Result<Arc<Self>, Errno> {
67        kernel.expando.get_or_try_init(|| error!(EINVAL))
68    }
69
70    /// Initialize the framebuffer device. Should only be called once per kernel.
71    pub fn device_init<L>(
72        locked: &mut Locked<L>,
73        system_task: &CurrentTask,
74        aspect_ratio: Option<AspectRatio>,
75        enable_visual_debugging: bool,
76    ) -> Result<Arc<Framebuffer>, Errno>
77    where
78        L: LockEqualOrBefore<FileOpsCore>,
79    {
80        let kernel = system_task.kernel();
81        let registry = &kernel.device_registry;
82
83        let framebuffer = kernel
84            .expando
85            .get_or_try_init(|| Framebuffer::new(aspect_ratio, enable_visual_debugging))?;
86
87        let graphics_class = registry.objects.graphics_class();
88        registry.register_device(
89            locked,
90            system_task,
91            "fb0".into(),
92            DeviceMetadata::new("fb0".into(), DeviceType::FB0, DeviceMode::Char),
93            graphics_class,
94            FramebufferDevice { framebuffer: framebuffer.clone() },
95        )?;
96
97        Ok(framebuffer)
98    }
99
100    /// Creates a new `Framebuffer` fit to the screen, while maintaining the provided aspect ratio.
101    ///
102    /// If the `aspect_ratio` is `None`, the framebuffer will be scaled to the display.
103    fn new(
104        aspect_ratio: Option<AspectRatio>,
105        enable_visual_debugging: bool,
106    ) -> Result<Self, Errno> {
107        let mut info = fb_var_screeninfo::default();
108
109        let display_size = get_display_size().unwrap_or(fmath::SizeU { width: 700, height: 1200 });
110
111        // If the container has a specific aspect ratio set, use that to fit the framebuffer
112        // inside of the display.
113        let (feature_width, feature_height) = aspect_ratio
114            .map(|ar| (ar.width, ar.height))
115            .unwrap_or((display_size.width, display_size.height));
116
117        // Scale to framebuffer to fit the display, while maintaining the expected aspect ratio.
118        let ratio =
119            std::cmp::min(display_size.width / feature_width, display_size.height / feature_height);
120        let (width, height) = (feature_width * ratio, feature_height * ratio);
121
122        info.xres = width;
123        info.yres = height;
124        info.xres_virtual = info.xres;
125        info.yres_virtual = info.yres;
126        info.bits_per_pixel = 32;
127        info.red = fb_bitfield { offset: 0, length: 8, msb_right: 0 };
128        info.green = fb_bitfield { offset: 8, length: 8, msb_right: 0 };
129        info.blue = fb_bitfield { offset: 16, length: 8, msb_right: 0 };
130        info.transp = fb_bitfield { offset: 24, length: 8, msb_right: 0 };
131
132        if let Ok((server, memory)) = FramebufferServer::new(width, height) {
133            let server = Arc::new(server);
134            let memory_len = memory.info()?.size_bytes as u32;
135
136            // Fill the buffer with black pixels as a placeholder, if visual debug is off.
137            // Fill the buffer with purple, if visual debug is on.
138            let background = if enable_visual_debugging {
139                [0xff, 0x00, 0xff, 0xff].repeat((memory_len / 4) as usize)
140            } else {
141                vec![0x00; memory_len as usize]
142            };
143
144            if let Err(err) = memory.write(&background, 0) {
145                log_warn!("could not write initial framebuffer: {:?}", err);
146            }
147
148            Ok(Self {
149                server: Some(server),
150                memory: Mutex::new(Some(memory)),
151                info: RwLock::new(info),
152                view_identity: Default::default(),
153                view_bound_protocols: Default::default(),
154            })
155        } else {
156            Ok(Self {
157                server: None,
158                memory: Default::default(),
159                info: RwLock::new(info),
160                view_identity: Default::default(),
161                view_bound_protocols: Default::default(),
162            })
163        }
164    }
165
166    /// Starts presenting a view based on this framebuffer.
167    ///
168    /// # Parameters
169    /// * `incoming_dir`: the incoming service directory under which the
170    ///   `fuchsia.element.GraphicalPresenter` protocol can be retrieved.
171    pub fn start_server(&self, kernel: &Kernel, incoming_dir: Option<fio::DirectoryProxy>) {
172        if let Some(server) = &self.server {
173            let view_bound_protocols = self.view_bound_protocols.lock().take().unwrap();
174            let view_identity = self.view_identity.lock().take().unwrap();
175            log_info!("Presenting view using GraphicalPresenter");
176            start_presentation_loop(
177                kernel,
178                server.clone(),
179                view_bound_protocols,
180                view_identity,
181                incoming_dir,
182            );
183        }
184    }
185
186    /// Starts presenting a child view instead of the framebuffer.
187    ///
188    /// # Parameters
189    /// * `viewport_token`: handles to the child view
190    pub fn present_view(&self, viewport_token: fuiviews::ViewportCreationToken) {
191        if let Some(server) = &self.server {
192            init_viewport_scene(server.clone(), viewport_token);
193
194            // Release the memory associated with the framebuffer.
195            let mut memory = self.memory.lock();
196            if let Some(memory_ref) = memory.as_ref() {
197                let bytes = memory_ref.get_size();
198                let refs = Arc::strong_count(memory_ref);
199                *memory = None;
200                log_info!("Released framebuffer memory ({} bytes, {} refs)", bytes, refs);
201            }
202        }
203    }
204
205    /// Returns the framebuffer's memory.
206    fn get_memory(&self) -> Result<Arc<MemoryObject>, Errno> {
207        self.memory.lock().clone().ok_or_else(|| errno!(EIO))
208    }
209
210    /// Returns the logical size of the framebuffer's memory.
211    fn memory_len(&self) -> usize {
212        self.memory
213            .lock()
214            .as_ref()
215            .map_or(0, |memory| memory.info().map_or(0, |info| info.size_bytes)) as usize
216    }
217
218    /// Returns the allocated size of the framebuffer's memory.
219    fn memory_size(&self) -> usize {
220        self.memory.lock().as_ref().map_or(0, |memory| memory.get_size()) as usize
221    }
222}
223
224#[derive(Clone)]
225struct FramebufferDevice {
226    framebuffer: Arc<Framebuffer>,
227}
228
229type FbFixScreeninfoPtr =
230    MultiArchUserRef<uapi::fb_fix_screeninfo, uapi::arch32::fb_fix_screeninfo>;
231type FbVarScreeninfoPtr =
232    MultiArchUserRef<uapi::fb_var_screeninfo, uapi::arch32::fb_var_screeninfo>;
233
234fn set_display_power(mode: fuidisplay::PowerMode) -> Result<(), Errno> {
235    let singleton_display_power =
236        connect_to_protocol_sync::<fuidisplay::DisplayPowerMarker>().map_err(|_| errno!(ENOENT))?;
237    singleton_display_power
238        .set_power_mode(mode, zx::MonotonicInstant::INFINITE)
239        .map_err(|_| errno!(EIO))?
240        .map_err(|_| errno!(EINVAL))?;
241    Ok(())
242}
243
244impl DeviceOps for FramebufferDevice {
245    fn open(
246        &self,
247        _locked: &mut Locked<FileOpsCore>,
248        _current_task: &CurrentTask,
249        dev: DeviceType,
250        node: &NamespaceNode,
251        _flags: OpenFlags,
252    ) -> Result<Box<dyn FileOps>, Errno> {
253        if dev.minor() != 0 {
254            return error!(ENODEV);
255        }
256        node.entry.node.update_info(|info| {
257            info.size = self.framebuffer.memory_len();
258            info.blocks = self.framebuffer.memory_size() / info.blksize;
259            Ok(())
260        })?;
261        Ok(Box::new(Arc::clone(&self.framebuffer)))
262    }
263}
264/// `Framebuffer` doesn't implement the `close` method.
265impl CloseFreeSafe for Framebuffer {}
266impl FileOps for Framebuffer {
267    fileops_impl_memory!(self, &self.get_memory()?);
268    fileops_impl_noop_sync!();
269
270    fn ioctl(
271        &self,
272        _locked: &mut Locked<Unlocked>,
273        _file: &FileObject,
274        current_task: &CurrentTask,
275        request: u32,
276        arg: SyscallArg,
277    ) -> Result<SyscallResult, Errno> {
278        let user_addr = UserAddress::from(arg);
279        match request {
280            FBIOGET_FSCREENINFO => {
281                let info = self.info.read();
282                let finfo = fb_fix_screeninfo {
283                    id: zerocopy::FromBytes::read_from_bytes(&b"Starnix\0\0\0\0\0\0\0\0\0"[..])
284                        .unwrap(),
285                    smem_start: 0,
286                    smem_len: self.memory_len() as u32,
287                    type_: FB_TYPE_PACKED_PIXELS,
288                    visual: FB_VISUAL_TRUECOLOR,
289                    line_length: info.bits_per_pixel / 8 * info.xres,
290                    ..fb_fix_screeninfo::default()
291                };
292                let user_ref = FbFixScreeninfoPtr::new(current_task, user_addr);
293                current_task.write_multi_arch_object(user_ref, finfo)?;
294                Ok(SUCCESS)
295            }
296
297            FBIOGET_VSCREENINFO => {
298                let info = self.info.read();
299                let user_ref = FbVarScreeninfoPtr::new(current_task, user_addr);
300                current_task.write_multi_arch_object(user_ref, *info)?;
301                Ok(SUCCESS)
302            }
303
304            FBIOPUT_VSCREENINFO => {
305                let user_ref = FbVarScreeninfoPtr::new(current_task, user_addr);
306                let new_info: fb_var_screeninfo = current_task.read_multi_arch_object(user_ref)?;
307                let old_info = self.info.read();
308                // We don't yet support actually changing anything
309                if new_info.as_bytes() != old_info.as_bytes() {
310                    return error!(EINVAL);
311                }
312                Ok(SUCCESS)
313            }
314
315            FBIOBLANK => {
316                let arg = u32::from(arg);
317                match arg {
318                    FB_BLANK_POWERDOWN => {
319                        set_display_power(fuidisplay::PowerMode::Off)?;
320                        Ok(SUCCESS)
321                    }
322                    FB_BLANK_UNBLANK => {
323                        set_display_power(fuidisplay::PowerMode::On)?;
324                        Ok(SUCCESS)
325                    }
326                    _ => {
327                        track_stub!(TODO("https://fxbug.dev/475633434"), "FBIOBLANK", arg);
328                        error!(EINVAL)
329                    }
330                }
331            }
332
333            _ => {
334                track_stub!(TODO("https://fxbug.dev/475633434"), "fb ioctl", request);
335                error!(EINVAL)
336            }
337        }
338    }
339}
starnix_modules_framebuffer/lib.rs

starnix_modules_framebuffer/
lib.rs
