Index: gpio_setup.cc |
diff --git a/gpio_setup.cc b/gpio_setup.cc |
new file mode 100644 |
index 0000000000000000000000000000000000000000..ac14d8343d32f5e451b9c4cbe2594d550a6a4ce0 |
--- /dev/null |
+++ b/gpio_setup.cc |
@@ -0,0 +1,464 @@ |
+// 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; |
+} |