1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
|
/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
* Copyright (C) 2019, Google Inc.
*
* framebuffer.cpp - Frame buffer handling
*/
#include <libcamera/framebuffer.h>
#include "libcamera/internal/framebuffer.h"
#include <sys/stat.h>
#include <libcamera/base/log.h>
#include <libcamera/base/shared_fd.h>
/**
* \file libcamera/framebuffer.h
* \brief Frame buffer handling
*
* \file libcamera/internal/framebuffer.h
* \brief Internal frame buffer handling support
*/
namespace libcamera {
LOG_DEFINE_CATEGORY(Buffer)
/**
* \struct FrameMetadata
* \brief Metadata related to a captured frame
*
* The FrameMetadata structure stores all metadata related to a captured frame,
* as stored in a FrameBuffer, such as capture status, timestamp and bytes used.
*/
/**
* \enum FrameMetadata::Status
* \brief Define the frame completion status
* \var FrameMetadata::FrameSuccess
* The frame has been captured with success and contains valid data. All fields
* of the FrameMetadata structure are valid.
* \var FrameMetadata::FrameError
* An error occurred during capture of the frame. The frame data may be partly
* or fully invalid. The sequence and timestamp fields of the FrameMetadata
* structure is valid, the other fields may be invalid.
* \var FrameMetadata::FrameCancelled
* Capture stopped before the frame completed. The frame data is not valid. All
* fields of the FrameMetadata structure but the status field are invalid.
*/
/**
* \struct FrameMetadata::Plane
* \brief Per-plane frame metadata
*
* Frames are stored in memory in one or multiple planes. The
* FrameMetadata::Plane structure stores per-plane metadata.
*/
/**
* \var FrameMetadata::Plane::bytesused
* \brief Number of bytes occupied by the data in the plane, including line
* padding
*
* This value may vary per frame for compressed formats. For uncompressed
* formats it will be constant for all frames, but may be smaller than the
* FrameBuffer size.
*/
/**
* \var FrameMetadata::status
* \brief Status of the frame
*
* The validity of other fields of the FrameMetadata structure depends on the
* status value.
*/
/**
* \var FrameMetadata::sequence
* \brief Frame sequence number
*
* The sequence number is a monotonically increasing number assigned to the
* frames captured by the stream. The value is increased by one for each frame.
* Gaps in the sequence numbers indicate dropped frames.
*/
/**
* \var FrameMetadata::timestamp
* \brief Time when the frame was captured
*
* The timestamp is expressed as a number of nanoseconds relative to the system
* clock since an unspecified time point.
*
* \todo Be more precise on what timestamps refer to.
*/
/**
* \fn FrameMetadata::planes()
* \copydoc FrameMetadata::planes() const
*/
/**
* \fn FrameMetadata::planes() const
* \brief Retrieve the array of per-plane metadata
* \return The array of per-plane metadata
*/
/**
* \class FrameBuffer::Private
* \brief Base class for FrameBuffer private data
*
* The FrameBuffer::Private class stores all private data associated with a
* framebuffer. It implements the d-pointer design pattern to hide core
* FrameBuffer data from the public API, and exposes utility functions to
* pipeline handlers.
*/
FrameBuffer::Private::Private()
: request_(nullptr), isContiguous_(true)
{
}
/**
* \brief FrameBuffer::Private destructor
*/
FrameBuffer::Private::~Private()
{
}
/**
* \fn FrameBuffer::Private::setRequest()
* \brief Set the request this buffer belongs to
* \param[in] request Request to set
*
* For buffers added to requests by applications, this function is called by
* Request::addBuffer() or Request::reuse(). For buffers internal to pipeline
* handlers, it is called by the pipeline handlers themselves.
*/
/**
* \fn FrameBuffer::Private::isContiguous()
* \brief Check if the frame buffer stores planes contiguously in memory
*
* Multi-planar frame buffers can store their planes contiguously in memory, or
* split them into discontiguous memory areas. This function checks in which of
* these two categories the frame buffer belongs.
*
* \return True if the planes are stored contiguously in memory, false otherwise
*/
/**
* \fn FrameBuffer::Private::fence()
* \brief Retrieve a const pointer to the Fence
*
* This function does only return a reference to the the fence and does not
* change its ownership. The fence is stored in the FrameBuffer and can only be
* reset with FrameBuffer::releaseFence() in case the buffer has completed with
* error due to a Fence wait failure.
*
* If buffer with a Fence completes with errors due to a failure in handling
* the fence, applications are responsible for releasing the Fence before
* calling Request::addBuffer() again.
*
* \sa Request::addBuffer()
*
* \return A const pointer to the Fence if any, nullptr otherwise
*/
/**
* \fn FrameBuffer::Private::setFence()
* \brief Move a \a fence in this buffer
* \param[in] fence The Fence
*
* This function associates a Fence with this Framebuffer. The intended caller
* is the Request::addBuffer() function.
*
* Once a FrameBuffer is associated with a Fence, the FrameBuffer will only be
* made available to the hardware device once the Fence has been correctly
* signalled.
*
* \sa Request::prepare()
*
* If the FrameBuffer completes successfully the core releases the Fence and the
* Buffer can be reused immediately. If handling of the Fence fails during the
* request preparation, the Fence is not released and is left in the
* FrameBuffer. It is applications responsibility to correctly release the
* fence and handle it opportunely before using the buffer again.
*/
/**
* \fn FrameBuffer::Private::cancel()
* \brief Marks the buffer as cancelled
*
* If a buffer is not used by a request, it shall be marked as cancelled to
* indicate that the metadata is invalid.
*/
/**
* \class FrameBuffer
* \brief Frame buffer data and its associated dynamic metadata
*
* The FrameBuffer class is the primary interface for applications, IPAs and
* pipeline handlers to interact with frame memory. It contains all the static
* and dynamic information to manage the whole life cycle of a frame capture,
* from buffer creation to consumption.
*
* The static information describes the memory planes that make a frame. The
* planes are specified when creating the FrameBuffer and are expressed as a set
* of dmabuf file descriptors, offset and length.
*
* The dynamic information is grouped in a FrameMetadata instance. It is updated
* during the processing of a queued capture request, and is valid from the
* completion of the buffer as signaled by Camera::bufferComplete() until the
* FrameBuffer is either reused in a new request or deleted.
*
* The creator of a FrameBuffer (application, IPA or pipeline handler) may
* associate to it an integer cookie for any private purpose. The cookie may be
* set when creating the FrameBuffer, and updated at any time with setCookie().
* The cookie is transparent to the libcamera core and shall only be set by the
* creator of the FrameBuffer. This mechanism supplements the Request cookie.
*/
/**
* \struct FrameBuffer::Plane
* \brief A memory region to store a single plane of a frame
*
* Planar pixel formats use multiple memory regions to store the different
* colour components of a frame. The Plane structure describes such a memory
* region by a dmabuf file descriptor, an offset within the dmabuf and a length.
* A FrameBuffer then contains one or multiple planes, depending on the pixel
* format of the frames it is meant to store.
*
* The offset identifies the location of the plane data from the start of the
* memory referenced by the dmabuf file descriptor. Multiple planes may be
* stored in the same dmabuf, in which case they will reference the same dmabuf
* and different offsets. No two planes may overlap, as specified by their
* offset and length.
*
* To support DMA access, planes are associated with dmabuf objects represented
* by SharedFD handles. The Plane class doesn't handle mapping of the memory to
* the CPU, but applications and IPAs may use the dmabuf file descriptors to map
* the plane memory with mmap() and access its contents.
*
* \todo Specify how an application shall decide whether to use a single or
* multiple dmabufs, based on the camera requirements.
*/
/**
* \var FrameBuffer::Plane::kInvalidOffset
* \brief Invalid offset value, to identify uninitialized planes
*/
/**
* \var FrameBuffer::Plane::fd
* \brief The dmabuf file descriptor
*/
/**
* \var FrameBuffer::Plane::offset
* \brief The plane offset in bytes
*/
/**
* \var FrameBuffer::Plane::length
* \brief The plane length in bytes
*/
namespace {
ino_t fileDescriptorInode(const SharedFD &fd)
{
if (!fd.isValid())
return 0;
struct stat st;
int ret = fstat(fd.get(), &st);
if (ret < 0) {
ret = -errno;
LOG(Buffer, Fatal)
<< "Failed to fstat() fd: " << strerror(-ret);
return 0;
}
return st.st_ino;
}
} /* namespace */
/**
* \brief Construct a FrameBuffer with an array of planes
* \param[in] planes The frame memory planes
* \param[in] cookie Cookie
*/
FrameBuffer::FrameBuffer(const std::vector<Plane> &planes, unsigned int cookie)
: FrameBuffer(std::make_unique<Private>(), planes, cookie)
{
}
/**
* \brief Construct a FrameBuffer with an extensible private class and an array
* of planes
* \param[in] d The extensible private class
* \param[in] planes The frame memory planes
* \param[in] cookie Cookie
*/
FrameBuffer::FrameBuffer(std::unique_ptr<Private> d,
const std::vector<Plane> &planes,
unsigned int cookie)
: Extensible(std::move(d)), planes_(planes), cookie_(cookie)
{
metadata_.planes_.resize(planes_.size());
unsigned int offset = 0;
bool isContiguous = true;
ino_t inode = 0;
for (const auto &plane : planes_) {
ASSERT(plane.offset != Plane::kInvalidOffset);
if (plane.offset != offset) {
isContiguous = false;
break;
}
/*
* Two different dmabuf file descriptors may still refer to the
* same dmabuf instance. Check this using inodes.
*/
if (plane.fd != planes_[0].fd) {
if (!inode)
inode = fileDescriptorInode(planes_[0].fd);
if (fileDescriptorInode(plane.fd) != inode) {
isContiguous = false;
break;
}
}
offset += plane.length;
}
LOG(Buffer, Debug)
<< "Buffer is " << (isContiguous ? "" : "not ") << "contiguous";
_d()->isContiguous_ = isContiguous;
}
/**
* \fn FrameBuffer::planes()
* \brief Retrieve the static plane descriptors
* \return Array of plane descriptors
*/
/**
* \brief Retrieve the request this buffer belongs to
*
* The intended callers of this function are buffer completion handlers that
* need to associate a buffer to the request it belongs to.
*
* A FrameBuffer is associated to a request by Request::addBuffer() and the
|
