add c++ version of the firmware utilities

gpio_setup.cc

+// Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// NOTE: this file is translated from gpio_setup.py
+//
+// A script to create symlinks to platform specific GPIO pins.
+//
+// This script creates a set of symlinks pointing at the sys fs files returning
+// the appropriate GPIO pin values. Each symlink is named to represent the
+// actual GPIO pin function.
+//
+// The location of the symlinks generated by this script can be specified using
+// the --symlink_root command line option. By default /home/gpio directory is
+// used. The symlink directory must exist before this script is run.
+//
+// The GPIO pins' values are available through a GPIO device present in sys fs.
+// The device is identified by its PCI bus address. The default PCI address of
+// the GPIO device (set to 0:0:1f.0), can be changed using the --pci_address
+// command line option.
+//
+// The platform specific bit usage of the GPIO device is derived from the ACPI,
+// also using files found in a fixed location in sys fs. The default location of
+// /sys/bus/platform/devices/chromeos_acpi could be changed using the
+// --acpi_root command line option.
+//
+// Each GPIO pin is represented through ACPI as a subdirectory with several
+// files in it. A typical name of the GPIO pin file looks as follows:
+//
+// <acpi_root>/GPIO.<instance>/GPIO.[0-3]
+//
+// where <instance> is a zero based number assigned to this GPIO pin by the BIOS
+//
+// In particular, file GPIO.0 represents encoded pin signal type (from which the
+// symlink name is derived), and file GPIO.2 represents the actual zero based
+// GPIO pin number within this GPIO device range.
+//
+// This script reads the ACPI provided mapping, enables the appropriate GPIO
+// pins and creates symlinks mapping these GPIOs' values.
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include <sys/param.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <stdarg.h>
+#include <ctype.h>
+#include <getopt.h>
+#include <glob.h>
+
+#include <string>
+#include <vector>
+#include <map>
+
+#define GPIO_ROOT               "/sys/class/gpio"
+#define GPIO_DEVICE_ROOT        GPIO_ROOT "/gpiochip"
+#define GPIO_ENABLE_FILE        GPIO_ROOT "export"
+
+// Can be changed using --pci_address command line option.
+#define DEFAULT_GPIO_DEVICE_PCI_ADDRESS "0000:00:1f.0"
+
+// Can be changed using --acpi_root command line option.
+#define DEFAULT_ACPI_ROOT "/sys/bus/platform/devices/chromeos_acpi"
+
+// can be changed using --symlink_root command line option.
+#define DEFAULT_SYMLINK_ROOT "/home/gpio"
+
+#define GPIO_SIGNAL_TYPE_EXTENSION      "0"
+#define GPIO_PIN_NUMBER_EXTENSION       "2"
+
+// Debug header signal type codes are offset by 0x100, the tuple below
+// represents the range of valid codes for the debug header. The range
+// starts at 0x100 and is 0x100 wide.
+const int GPIO_DEBUG_HEADER_RANGE[2] = { 0x100, 0x100 };
+
+// This dictionary maps GPIO signal types codes into their actual names.
+const char *GPIO_SIGNAL_TYPES[] = {
+  NULL,                         // note: 0 is NOT a valid index, so we must
+                                // check the range by GPIO_SIGNAL_TYPE_MIN/MAX.
+  "recovery_button",            // index: 1
+  "developer_switch",           // index: 2
+  "write_protect",              // index: 3
+};
+
+// calculate the dimension and min/max values.
+#define GPIO_SIGNAL_TYPES_DIM \
+  (sizeof(GPIO_SIGNAL_TYPES)/sizeof(GPIO_SIGNAL_TYPES[0]))
+#define GPIO_SIGNAL_TYPE_MIN    (1)
+#define GPIO_SIGNAL_TYPE_MAX    (GPIO_SIGNAL_TYPES_DIM-1)
+// note: the above TYPE_MIN and TYPE_MAX refer to minimal and maximum valid
+// index values, so the '1' in MAX definition (DIM-1) does not mean
+// GPIO_SIGNAL_TYPE_MIN; it's for calculation to a 'zero-based array'.
+
+///////////////////////////////////////////////////////////////////////
+// Utilities for quick python-C translation
+
+using std::string;
+#define GPIO_STRING_BUFFER_LEN  (4096)  // general buffer length
+
+// Works like throwing an exception - directly exit here.
+static void GpioSetupError(const char *message, ...) {
+  va_list args;
+  va_start(args, message);
+  vfprintf(stderr, message, args);
+  fprintf(stderr, "\n");
+  va_end(args);
+  exit(1);
+}
+
+// Return: python - open(filename).read().strip()
+static string open_read_strip(const char *filename) {
+  FILE *fp = fopen(filename, "rt");
+  string result;
+  if (!fp)
+    return "";
+
+  // for virtual files (directly supported by kernel),
+  // it is better to 'read one line of text and strip'.
+  // for all files accessed by this utility should not
+  // contain very long text in first line, so using
+  // GPIO_STRING_BUFFER_LEN should be enough.
+  char buffer[GPIO_STRING_BUFFER_LEN] = "";
+
+  if (fgets(buffer, sizeof(buffer), fp) == NULL) {
+    perror(filename);
+  }
+  fclose(fp);
+
+  // now check leading and trailing spaces
+  char *head = buffer, *tail = head + strlen(head);
+  while (*head && isascii(*head) && isspace(*head))
+    head++;
+  while (tail > head && isascii(tail[-1]) && isspace(tail[-1]))
+    tail--;
+
+  return string(head, tail);
+}
+
+static string open_read_strip(const string &filename) {
+  return open_read_strip(filename.c_str());
+}
+
+static bool os_path_exists(const char *filename) {
+  return ::access(filename, 0) == 0;
+}
+
+static bool os_path_exists(const string &filename) {
+  return os_path_exists(filename.c_str());
+}
+
+static void os_symlink(const string &src, const string &dest) {
+  if (::symlink(src.c_str(), dest.c_str()) != 0) {
+    perror(src.c_str());
+    GpioSetupError("cannot create symlink (%s -> %s)",
+                   src.c_str(), dest.c_str());
+  }
+}
+
+static string os_readlink(const string &filename) {
+  char buf[PATH_MAX] = "";
+  if (::readlink(filename.c_str(), buf, sizeof(buf)-1) == -1) {
+    perror(filename.c_str());
+    GpioSetupError("cannot read link (%s)", filename.c_str());
+  }
+  return buf;
+}
+
+static string os_path_abspath(const string &src) {
+  // TODO(hungte) there's no simple equivelent in POSIX.
+  // since this is for debug message only, let's ignore it.
+  return src;
+}
+
+static bool os_path_isdir(const char *filename) {
+  struct stat st = {0};
+  if (stat(filename, &st) != 0) {
+    perror(filename);
+    GpioSetupError("cannot query path status: %s", filename);
+  }
+  return S_ISDIR(st.st_mode);
+}
+
+static bool os_path_islink(const string &src) {
+  struct stat st = {0};
+  if (lstat(src.c_str(), &st) != 0) {
+    perror(src.c_str());
+    GpioSetupError("cannot query link status: %s", src.c_str());
+  }
+  return S_ISLNK(st.st_mode);
+}
+
+static string os_path_dirname(const string &filename) {
+  // XXX here a full non-directory input (dir+file) name is assumed.
+  assert(!os_path_isdir(filename.c_str()));
+  string newname = filename;
+  size_t pos_slash = newname.rfind('/');
+  if (pos_slash != newname.npos)
+    newname.erase(pos_slash);
+  return newname;
+}
+
+typedef std::vector<string> GlobResult;
+
+static GlobResult glob_glob(const string &pattern) {
+  GlobResult r;
+  glob_t globtok = {0};
+  if (glob(pattern.c_str(),
+           GLOB_ERR | GLOB_TILDE, NULL, &globtok) == 0) {
+    for (size_t i = 0; i < globtok.gl_pathc; i++) {
+      r.push_back(globtok.gl_pathv[i]);
+    }
+    globfree(&globtok);
+  }
+  return r;
+}
+
+// Return: python - format % (...)
+static string format_string(const char *format, ...) {
+  char buffer[GPIO_STRING_BUFFER_LEN];  // large enough for current version
+  va_list args;
+  va_start(args, format);
+  vsnprintf(buffer, sizeof(buffer), format, args);
+  va_end(args);
+  return buffer;
+}
+
+///////////////////////////////////////////////////////////////////////
+
+// Represent GPIO chip available through sys fs.
+// Attributes:
+//  pci_address: a string, PCI address of this GPIO device
+//  base: a number, base global GPIO number of this device (mapped to pin zero
+//        in the device range)
+//  capacity: a number, shows the number of GPIO pins of this device.
+//  description: a multiline string description of this device, initialized
+//               after the device is attached. Can be used to dump device
+//               information.
+class GpioChip {
+ public:
+  explicit GpioChip(const string &pci_address) {
+    pci_address_ = pci_address;
+    base_ = 0;
+    capacity_ = 0;
+    description_ = "not attached";
+  }
+
+  void Attach() {
+    string f;
+    GlobResult r = glob_glob(GPIO_DEVICE_ROOT "*/label");
+
+    for (GlobResult::iterator i = r.begin(); i != r.end(); ++i) {
+      string label = open_read_strip(*i);
+      if (label == pci_address_) {
+        f = *i;
+        break;
+      }
+    }
+
+    if (f.empty())
+      GpioSetupError("could not find GPIO PCI device %s", pci_address_.c_str());
+
+    string directory = os_path_dirname(f);
+    base_ = atoi(open_read_strip(directory + "/base").c_str());
+    capacity_ = atoi(open_read_strip(directory + "/ngpio").c_str());
+    description_ = format_string(
+        "GPIO device at PCI address %s\n"
+        "Base gpio pin %d\n"
+        "Capacity %d\n",
+        pci_address_.c_str(), base_, capacity_);
+  }
+
+  // Enable a certain GPIO pin.
+  // To enable the pin one needs to write its global GPIO number into
+  // /sys/class/gpio/export, if this pin has not been enabled yet.
+  // Inputs:
+  //  pin: a number, zero based pin number within this device's range.
+  void EnablePin(int pin) {
+    if (pin >= capacity_)
+      GpioSetupError("pin %d exceeds capacity of %d", pin, capacity_);
+
+    // XXX in python version, this is named as 'global_gpio_number'
+    // although it's not really global.
+    int gpio_number = base_ + pin;
+
+    string target = format_string("%s/gpio%d", GPIO_ROOT, gpio_number);
+    if (!os_path_exists(target)) {
+      FILE *fp = fopen(GPIO_ENABLE_FILE, "w");
+      fprintf(fp, "%d", gpio_number);
+      fclose(fp);
+    }
+  }
+
+  // quick python-like translators
+  int base() const { return base_; }
+  int capacity() const { return capacity_; }
+
+  operator const char *() const {
+    return description_.c_str();
+  }
+
+ private:
+  string pci_address_;
+  int    base_;
+  int    capacity_;
+  string description_;
+
+  GpioChip() { }
+};
+
+typedef std::pair<string, int> AcpiMappingEntry;
+typedef std::vector<AcpiMappingEntry> AcpiMapping;
+
+// Scan ACPI information about GPIO and generate a mapping.
+//
+// Returns: a list of tuples, each tuple consisting of a string representing
+//          the GPIO pin name and a number, representing the GPIO pin within
+//          the GPIO device space.
+AcpiMapping ParseAcpiMappings(const string &acpi_root) {
+  GlobResult r = glob_glob(format_string("%s/GPIO.[0-9]*", acpi_root.c_str()));
+  AcpiMapping acpi_gpio_mapping;
+  GlobResult::iterator i;
+  for (i = r.begin(); i != r.end(); i++) {
+    const char *d = i->c_str();
+    int signal_type = atoi(open_read_strip(
+        format_string("%s/GPIO.%s", d, GPIO_SIGNAL_TYPE_EXTENSION)).c_str());
+    int pin_number = atoi(open_read_strip(
+        format_string("%s/GPIO.%s", d, GPIO_PIN_NUMBER_EXTENSION)).c_str());
+
+    if (signal_type >= GPIO_SIGNAL_TYPE_MIN &&
+        signal_type <= static_cast<int>(GPIO_SIGNAL_TYPE_MAX) &&
+        GPIO_SIGNAL_TYPES[signal_type] != NULL) {
+      acpi_gpio_mapping.push_back(AcpiMappingEntry(
+          GPIO_SIGNAL_TYPES[signal_type], pin_number));
+      continue;
+    }
+
+    // This is not a specific signal, could be a debug header pin.
+    int debug_header = signal_type - GPIO_DEBUG_HEADER_RANGE[0];
+    if (debug_header >= 0 && debug_header < GPIO_DEBUG_HEADER_RANGE[1]) {
+      acpi_gpio_mapping.push_back(AcpiMappingEntry(
+          format_string("debug_header_%d", debug_header), pin_number));
+      continue;
+    }
+
+    // Unrecognized mapping, could happen if BIOS version is ahead of this
+    // script.
+    printf("unknown signal type encoding %d in %s\n", signal_type, d);
+  }
+
+  if (acpi_gpio_mapping.empty())
+    GpioSetupError("no gpio mapping found. Is ACPI driver installed?");
+
+  return acpi_gpio_mapping;
+}
+
+void CreateGpioSymlinks(const AcpiMapping& mappings,
+                        GpioChip &gpio,
+                        const char *symlink_root) {
+  if (!os_path_exists(symlink_root))
+    GpioSetupError("%s does not exist", symlink_root);
+
+  if (!os_path_isdir(symlink_root))
+    GpioSetupError("%s is not a directory", symlink_root);
+
+  if (access(symlink_root, W_OK) != 0)
+    GpioSetupError("%s is not writable", symlink_root);
+
+  if (chdir(symlink_root) != 0)
+    GpioSetupError("failed to change directory to %s", symlink_root);
+
+  AcpiMapping::const_iterator i;
+  for (i = mappings.begin(); i != mappings.end(); ++i) {
+    string symlink = i->first;
+    int pin = i->second;
+    gpio.EnablePin(pin);
+
+    string source_file = format_string("%s/gpio%d/value",
+                                       GPIO_ROOT, pin+gpio.base());
+    if (!os_path_exists(symlink)) {
+      os_symlink(source_file.c_str(), symlink.c_str());
+      continue;
+    }
+
+    if (!os_path_islink(symlink))
+      GpioSetupError("%s exists but is not a symlink",
+                     os_path_abspath(symlink).c_str());
+
+    if (os_readlink(symlink) != source_file)
+      GpioSetupError("%s points to a wrong file",
+                     os_path_abspath(symlink).c_str());
+  }
+}
+
+static const char *__name__ = "";
+static void usage_help_exit(int ret) {
+  printf(
+      "Usage: %s [options]\n"
+      "\n"
+      "Options:\n"
+      "  -h, --help \t show this help message and exit\n"
+      "  --symlink_root=SYMLINK_ROOT\n"
+      "  --pci_address=PCI_ADDRESS\n"
+      "  --acpi_root=ACPI_ROOT\n", __name__);
+  exit(ret);
+}
+
+int main(int argc, char *argv[]) {
+  __name__ = argv[0];
+
+  struct GpioSetupOptions {
+    string pci_address,
+           symlink_root,
+           acpi_root;
+  } cmd_line_options;
+
+  // copy default values
+  cmd_line_options.pci_address = DEFAULT_GPIO_DEVICE_PCI_ADDRESS;
+  cmd_line_options.symlink_root = DEFAULT_SYMLINK_ROOT;
+  cmd_line_options.acpi_root = DEFAULT_ACPI_ROOT;
+
+  // ProcessOptions();
+  const struct option longopts[] = {
+    { "pci_address", 1, NULL, 'p' },
+    { "symlink_root", 1, NULL, 's' },
+    { "acpi_root", 1, NULL, 'a' },
+    { "help", 0, NULL, 'h'},
+    { 0 },
+  };
+
+  int optc;
+  while ((optc = getopt_long(argc, argv, "h", longopts, NULL)) != -1) {
+    switch (optc) {
+      case 'p':
+        cmd_line_options.pci_address = optarg;
+        break;
+
+      case 's':
+        cmd_line_options.symlink_root = optarg;
+        break;
+
+      case 'a':
+        cmd_line_options.acpi_root = optarg;
+        break;
+
+      default:
+        usage_help_exit(1);
+        break;
+    }
+  }
+
+  // currently no other non-dashed arguments allowed.
+  if (optind != argc)
+    usage_help_exit(1);
+
+  GpioChip gpioc(cmd_line_options.pci_address);
+  gpioc.Attach();
+  CreateGpioSymlinks(
+      ParseAcpiMappings(cmd_line_options.acpi_root),
+      gpioc, cmd_line_options.symlink_root.c_str());
+  return 0;
+}