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authorPaul Elder <paul.elder@ideasonboard.com>2019-05-02 16:50:49 -0400
committerPaul Elder <paul.elder@ideasonboard.com>2019-05-03 16:31:10 -0400
commit977cfbd526f2da1cfce5c5c2b187c83af3d3efdc (patch)
treebc80ecc5b23a7a78c1c019b31aff0ad62600339a
parent05ff3d56e04a33756a679d24fe5542e9e50935b4 (diff)
libcamera: device_enumerator: add DeviceEnumeratorSysfs class
A udev-based device enumerator is not sufficient, since libudev is an optional dependency, or udev might fail. In these cases, we should fall back to using sysfs to enumerate devices. Add a DeviceEnumeratorSysfs class which is a specialization of DeviceEnumerator that uses sysfs to enumerate media devices on the system. Signed-off-by: Paul Elder <paul.elder@ideasonboard.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
-rw-r--r--Documentation/Doxyfile.in4
-rw-r--r--src/libcamera/device_enumerator.cpp6
-rw-r--r--src/libcamera/device_enumerator_sysfs.cpp105
-rw-r--r--src/libcamera/include/device_enumerator_sysfs.h28
-rw-r--r--src/libcamera/meson.build2
5 files changed, 142 insertions, 3 deletions
diff --git a/Documentation/Doxyfile.in b/Documentation/Doxyfile.in
index 950ad4fe..381f7771 100644
--- a/Documentation/Doxyfile.in
+++ b/Documentation/Doxyfile.in
@@ -833,7 +833,9 @@ RECURSIVE = YES
# Note that relative paths are relative to the directory from which doxygen is
# run.
-EXCLUDE = ../src/libcamera/device_enumerator_udev.cpp \
+EXCLUDE = ../src/libcamera/device_enumerator_sysfs.cpp \
+ ../src/libcamera/device_enumerator_udev.cpp \
+ ../src/libcamera/include/device_enumerator_sysfs.h \
../src/libcamera/include/device_enumerator_udev.h \
../src/libcamera/pipeline/
diff --git a/src/libcamera/device_enumerator.cpp b/src/libcamera/device_enumerator.cpp
index f6878b3d..259eec41 100644
--- a/src/libcamera/device_enumerator.cpp
+++ b/src/libcamera/device_enumerator.cpp
@@ -6,6 +6,7 @@
*/
#include "device_enumerator.h"
+#include "device_enumerator_sysfs.h"
#include "device_enumerator_udev.h"
#include <string.h>
@@ -153,8 +154,9 @@ std::unique_ptr<DeviceEnumerator> DeviceEnumerator::create()
* Either udev is not available or udev initialization failed. Fall back
* on the sysfs enumerator.
*/
-
- /** \todo Add a sysfs-based enumerator. */
+ enumerator = utils::make_unique<DeviceEnumeratorSysfs>();
+ if (!enumerator->init())
+ return enumerator;
return nullptr;
}
diff --git a/src/libcamera/device_enumerator_sysfs.cpp b/src/libcamera/device_enumerator_sysfs.cpp
new file mode 100644
index 00000000..f3054d5e
--- /dev/null
+++ b/src/libcamera/device_enumerator_sysfs.cpp
@@ -0,0 +1,105 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2019, Google Inc.
+ *
+ * device_enumerator_sysfs.cpp - sysfs-based device enumerator
+ */
+
+#include "device_enumerator_sysfs.h"
+
+#include <dirent.h>
+#include <fcntl.h>
+#include <fstream>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "log.h"
+
+namespace libcamera {
+
+LOG_DECLARE_CATEGORY(DeviceEnumerator)
+
+int DeviceEnumeratorSysfs::init()
+{
+ return 0;
+}
+
+int DeviceEnumeratorSysfs::enumerate()
+{
+ struct dirent *ent;
+ DIR *dir;
+
+ static const char * const sysfs_dirs[] = {
+ "/sys/subsystem/media/devices",
+ "/sys/bus/media/devices",
+ "/sys/class/media/devices",
+ };
+
+ for (const char *dirname : sysfs_dirs) {
+ dir = opendir(dirname);
+ if (dir)
+ break;
+ }
+
+ if (!dir) {
+ LOG(DeviceEnumerator, Error)
+ << "No valid sysfs media device directory";
+ return -ENODEV;
+ }
+
+ while ((ent = readdir(dir)) != nullptr) {
+ if (strncmp(ent->d_name, "media", 5))
+ continue;
+
+ char *end;
+ unsigned int idx = strtoul(ent->d_name + 5, &end, 10);
+ if (*end != '\0')
+ continue;
+
+ std::string devnode = "/dev/media" + std::to_string(idx);
+
+ /* Verify that the device node exists. */
+ struct stat devstat;
+ if (stat(devnode.c_str(), &devstat) < 0) {
+ LOG(DeviceEnumerator, Warning)
+ << "Device node /dev/media" << idx
+ << " should exist but doesn't";
+ continue;
+ }
+
+ addDevice(devnode);
+ }
+
+ closedir(dir);
+
+ return 0;
+}
+
+std::string DeviceEnumeratorSysfs::lookupDeviceNode(int major, int minor)
+{
+ std::string deviceNode;
+ std::string line;
+ std::ifstream ueventFile;
+
+ ueventFile.open("/sys/dev/char/" + std::to_string(major) + ":" +
+ std::to_string(minor) + "/uevent");
+ if (!ueventFile)
+ return std::string();
+
+ while (ueventFile >> line) {
+ if (line.find("DEVNAME=") == 0) {
+ deviceNode = "/dev/" + line.substr(strlen("DEVNAME="));
+ break;
+ }
+ }
+
+ ueventFile.close();
+
+ return deviceNode;
+}
+
+} /* namespace libcamera */
diff --git a/src/libcamera/include/device_enumerator_sysfs.h b/src/libcamera/include/device_enumerator_sysfs.h
new file mode 100644
index 00000000..8d3adc91
--- /dev/null
+++ b/src/libcamera/include/device_enumerator_sysfs.h
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2019, Google Inc.
+ *
+ * device_enumerator_sysfs.h - sysfs-based device enumerator
+ */
+#ifndef __LIBCAMERA_DEVICE_ENUMERATOR_SYSFS_H__
+#define __LIBCAMERA_DEVICE_ENUMERATOR_SYSFS_H__
+
+#include <string>
+
+#include "device_enumerator.h"
+
+namespace libcamera {
+
+class DeviceEnumeratorSysfs final : public DeviceEnumerator
+{
+public:
+ int init();
+ int enumerate();
+
+private:
+ std::string lookupDeviceNode(int major, int minor);
+};
+
+} /* namespace libcamera */
+
+#endif /* __LIBCAMERA_DEVICE_ENUMERATOR_SYSFS_H__ */
diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build
index 2b678237..8796f49b 100644
--- a/src/libcamera/meson.build
+++ b/src/libcamera/meson.build
@@ -4,6 +4,7 @@ libcamera_sources = files([
'camera_manager.cpp',
'camera_sensor.cpp',
'device_enumerator.cpp',
+ 'device_enumerator_sysfs.cpp',
'event_dispatcher.cpp',
'event_dispatcher_poll.cpp',
'event_notifier.cpp',
@@ -26,6 +27,7 @@ libcamera_sources = files([
libcamera_headers = files([
'include/camera_sensor.h',
'include/device_enumerator.h',
+ 'include/device_enumerator_sysfs.h',
'include/device_enumerator_udev.h',
'include/event_dispatcher_poll.h',
'include/formats.h',