626172a16b
Source files in libcamera start by a comment block header, which
includes the file name and a one-line description of the file contents.
While the latter is useful to get a quick overview of the file contents
at a glance, the former is mostly a source of inconvenience. The name in
the comments can easily get out of sync with the file name when files
are renamed, and copy & paste during development have often lead to
incorrect names being used to start with.
Readers of the source code are expected to know which file they're
looking it. Drop the file name from the header comment block.
The change was generated with the following script:
----------------------------------------
dirs="include/libcamera src test utils"
declare -rA patterns=(
['c']=' \* '
['cpp']=' \* '
['h']=' \* '
['py']='# '
['sh']='# '
)
for ext in ${!patterns[@]} ; do
files=$(for dir in $dirs ; do find $dir -name "*.${ext}" ; done)
pattern=${patterns[${ext}]}
for file in $files ; do
name=$(basename ${file})
sed -i "s/^\(${pattern}\)${name} - /\1/" "$file"
done
done
----------------------------------------
This misses several files that are out of sync with the comment block
header. Those will be addressed separately and manually.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
112 lines
2.7 KiB
C++
112 lines
2.7 KiB
C++
/* SPDX-License-Identifier: LGPL-2.1-or-later */
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/*
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* Copyright (C) 2020, Google Inc.
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*
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* Miscellaneous utility functions to access sysfs
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*/
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#include "libcamera/internal/sysfs.h"
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#include <fstream>
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#include <sstream>
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#include <sys/stat.h>
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#include <sys/sysmacros.h>
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#include <libcamera/base/file.h>
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#include <libcamera/base/log.h>
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/**
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* \file sysfs.h
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* \brief Miscellaneous utility functions to access sysfs
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*/
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namespace libcamera {
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LOG_DEFINE_CATEGORY(SysFs)
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namespace sysfs {
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/**
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* \brief Retrieve the sysfs path for a character device
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* \param[in] deviceNode Path to character device node
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* \return The sysfs path on success or an empty string on failure
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*/
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std::string charDevPath(const std::string &deviceNode)
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{
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struct stat st;
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int ret = stat(deviceNode.c_str(), &st);
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if (ret < 0) {
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ret = -errno;
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LOG(SysFs, Error)
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<< "Unable to stat '" << deviceNode << "': "
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<< strerror(-ret);
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return {};
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}
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std::ostringstream dev("/sys/dev/char/", std::ios_base::ate);
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dev << major(st.st_rdev) << ":" << minor(st.st_rdev);
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return dev.str();
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}
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/**
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* \brief Retrieve the path of the firmware node for a device
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* \param[in] device Path in sysfs to search
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*
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* Physical devices in a system are described by the system firmware. Depending
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* on the type of platform, devices are identified using different naming
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* schemes. The Linux kernel abstract those differences with "firmware nodes".
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* This function retrieves the firmware node path corresponding to the
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* \a device.
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*
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* For DT-based systems, the path is the full name of the DT node that
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* represents the device. For ACPI-based systems, the path is the absolute
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* namespace path to the ACPI object that represents the device. In both cases,
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* the path is guaranteed to be unique and persistent as long as the system
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* firmware is not modified.
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*
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* \return The firmware node path on success or an empty string on failure
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*/
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std::string firmwareNodePath(const std::string &device)
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{
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std::string fwPath, node;
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struct stat st;
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/* Lookup for DT-based systems */
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node = device + "/of_node";
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if (!stat(node.c_str(), &st)) {
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char *ofPath = realpath(node.c_str(), nullptr);
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if (!ofPath)
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return {};
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static const char prefix[] = "/sys/firmware/devicetree";
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if (strncmp(ofPath, prefix, strlen(prefix)) == 0)
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fwPath = ofPath + strlen(prefix);
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else
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fwPath = ofPath;
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free(ofPath);
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return fwPath;
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}
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/* Lookup for ACPI-based systems */
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node = device + "/firmware_node/path";
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if (File::exists(node)) {
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std::ifstream file(node);
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if (!file.is_open())
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return {};
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std::getline(file, fwPath);
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file.close();
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return fwPath;
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}
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return {};
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}
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} /* namespace sysfs */
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} /* namespace libcamera */
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