/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <fcntl.h>
#include <string>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

#include <map>
#include <string>

#include <base/logging.h>
#include <hardware/hardware.h>
#include <hardware/peripheral_io.h>

// Path to sysfd gpio.
const char kSysfsGpioPathPrefix[] = "/sys/class/gpio/gpio";

// Path to export file.
const char kSysfsGpioExportPath[] = "/sys/class/gpio/export";

// Direction filename.
const char kDirection[] = "direction";

// Value filename.
const char kValue[] = "value";

static bool write_to_file(const std::string& path, const std::string& val) {
  int fd = open(path.c_str(), O_WRONLY);
  if (fd < 0)
    return false;
  ssize_t bytes = write(fd, val.c_str(), val.size());
  close(fd);
  if (bytes < 0)
    return false;
  if ((size_t)bytes != val.size())
    return false;
  return true;
}

static bool export_gpio(uint32_t index) {
  std::string path = kSysfsGpioPathPrefix + std::to_string(index);
  struct stat stat_buf;
  if (!stat(path.c_str(), &stat_buf))
    return true;

  return write_to_file(kSysfsGpioExportPath, std::to_string(index));
}

static bool set_pin_direction(uint32_t index, const std::string& val) {
  export_gpio(index);
  std::string path =
      kSysfsGpioPathPrefix + std::to_string(index) + "/direction";
  return write_to_file(path, val);
}

static bool set_pin_val(uint32_t index, int val) {
  export_gpio(index);
  set_pin_direction(index, "out");
  std::string path = kSysfsGpioPathPrefix + std::to_string(index) + "/value";
  return write_to_file(path, std::to_string(val));
}

static bool set_output_buffer(uint32_t index, int val) {
  export_gpio(index);
  std::string path = kSysfsGpioPathPrefix + std::to_string(index) + "/value";
  return write_to_file(path, std::to_string(val));
}

static bool set_mux_pin(uint32_t index, int val) {
  set_pin_val(index, val);
  return true;
}

static bool set_mode(uint32_t index, int val) {
  export_gpio(index);
  std::string path = kSysfsGpioPathPrefix + std::to_string(index) + "/pinmux";
  return write_to_file(path, std::to_string(val));
}

struct EdisonPin {
  uint32_t index;
  uint32_t output_buffer;
};

std::map<std::string, EdisonPin> board_pins = {
    {"IO0", {130, 248}}, {"IO1", {131, 249}},  {"IO2", {128, 250}},
    {"IO3", {12, 251}},  {"IO4", {129, 252}},  {"IO5", {13, 253}},
    {"IO6", {182, 254}}, {"IO7", {48, 255}},   {"IO8", {49, 256}},
    {"IO9", {183, 257}}, {"IO10", {41, 258}},  {"IO11", {43, 259}},
    {"IO12", {42, 260}}, {"IO13", {40, 261}},  {"IO14", {44, 232}},
    {"IO15", {45, 233}}, {"IO16", {46, 234}},  {"IO17", {47, 235}},
    {"IO18", {14, 236}}, {"IO19", {165, 237}},
};

static int pin_mux(const char* pin, const char* source) {
  std::string pin_name(pin);

  // If source is NULL, PIO is requesting GPIO.
  if (!source) {
    if (!board_pins.count(pin_name)) {
      LOG(ERROR) << "PIO HAL: Unknown GPIO pin " << pin_name;
      return false;
    }

    // Pin mode is always 0 for gpio.
    set_mode(board_pins[pin_name].index, 0);
    // Default to output buffer to input
    set_output_buffer(board_pins[pin_name].output_buffer, 0);

    // The following pins have an extra mux to set
    if (pin_name == "IO10") {
      set_mux_pin(263, 1);
      set_mux_pin(240, 0);
      set_mode(111, 0);
    } else if (pin_name == "IO11") {
      set_mux_pin(262, 1);
      set_mux_pin(241, 0);
      set_mode(115, 0);
    } else if (pin_name == "IO12") {
      set_mux_pin(242, 0);
      set_mode(114, 0);
    } else if (pin_name == "IO13") {
      set_mux_pin(243, 0);
      set_mode(109, 0);
    } else if (pin_name == "IO14") {
      set_mux_pin(200, 0);
    } else if (pin_name == "IO15") {
      set_mux_pin(201, 0);
    } else if (pin_name == "IO16") {
      set_mux_pin(202, 0);
    } else if (pin_name == "IO17") {
      set_mux_pin(203, 0);
    } else if (pin_name == "IO18") {
      set_mux_pin(204, 0);
    } else if (pin_name == "IO19") {
      set_mux_pin(205, 0);
    }
    return true;
  }

  std::string s = source;

  // Configure SPI2
  if (s == "SPI") {
    if (pin_name == "IO10") {
      set_pin_direction(226, "in");
      set_mode(111, 1);
      set_mux_pin(263, 1);
      set_mux_pin(240, 1);
      set_output_buffer(258, 1);
      return true;
    }
    if (pin_name == "IO11") {
      set_pin_direction(227, "in");
      set_mode(115, 1);
      set_mux_pin(262, 1);
      set_mux_pin(241, 1);
      set_output_buffer(259, 1);
      return true;
    }
    if (pin_name == "IO12") {
      set_pin_direction(228, "in");
      set_output_buffer(260, 0);
      set_mode(114, 1);
      set_mux_pin(242, 1);
      return true;
    }
    if (pin_name == "IO13") {
      set_output_buffer(261, 0);
      set_pin_direction(229, "in");
      set_mode(109, 1);
      set_mode(40, 1);
      set_mux_pin(243, 1);
      set_output_buffer(261, 1);
      return true;
    }
    LOG(ERROR) << "PIO HAL: Unknown SPI pin " << pin_name;
    return false;
  }

  // Configure I2C
  if (s == "I2C") {
    if (pin_name == "IO18") {
      set_pin_direction(212, "in");
      set_pin_direction(14, "in");
      set_mode(28, 1);
      set_mode(14, 1);
      set_mux_pin(204, 0);
      set_output_buffer(236, 0);
      return true;
    }
    if (pin_name == "IO19") {
      set_pin_direction(213, "in");
      set_pin_direction(165, "in");
      set_mode(165, 1);
      set_mode(27, 1);
      set_mux_pin(205, 0);
      set_output_buffer(237, 0);
      return true;
    }
    LOG(ERROR) << "PIO HAL: Unknown I2C pin " << pin_name;
  }

  if (s == "UART") {

    if (pin_name == "IO0") {
      set_pin_direction(248, "out");
      set_pin_direction(216, "out");
      set_output_buffer(248, 0);
      set_output_buffer(216, 0);
      set_mode(130, 1);
    } else if(pin_name == "IO1") {
      set_pin_direction(249, "out");
      set_pin_direction(217, "in");
      set_output_buffer(249, 1);
      set_mode(131, 1);
    }
  }

  return false;
}

static int pin_mux_direction(const char* pin, int dir) {
  std::string pin_name(pin);

  if (!board_pins.count(pin_name)) {
    LOG(ERROR) << "PIO HAL: Unknown GPIO pin " << pin_name;
    return false;
  }
  set_output_buffer(board_pins[pin_name].output_buffer, dir);

  return true;
}

static int register_device(const peripheral_io_module_t* dev,
                           const peripheral_registration_cb_t* callbacks) {
  LOG(INFO) << "Registering Edison's PIO HAL";
  (void)dev;
  // Set up pin muxing and register GPIO pins.
  for (auto& pin : board_pins) {
    callbacks->register_pin(pin.first.c_str(), true,
                            {pin_mux, pin_mux_direction});
    callbacks->register_gpio_sysfs(pin.first.c_str(), pin.second.index);
    callbacks->set_gpio_pin_mux(pin.first.c_str(), pin.first.c_str());
    set_pin_direction(pin.second.output_buffer, "low");
  }
  const char* spi_pins[4] = {"IO10", "IO11", "IO12", "IO13"};
  callbacks->register_simple_source("SPI", spi_pins, 4);

  // Register the SPI bus
  callbacks->register_spi_dev_bus("SPI2", 5, 1);
  callbacks->set_spi_pin_mux("SPI2", "SPI");

  const char* i2c_pins[2] = {"IO18", "IO19"};
  callbacks->register_simple_source("I2C", i2c_pins, 2);

  // Register the I2C bus
  callbacks->register_i2c_dev_bus("I2C6", 6);
  callbacks->set_i2c_pin_mux("I2C6", "I2C");

  const char* uart_pins[2] = {"IO0", "IO1"};
  callbacks->register_simple_source("UART", uart_pins, 2);

  // TODO(leecam): Add UART back in once UART code lands
  //callbacks->register_uart_bus("UART1", "/dev/ttyMFD1");
  //callbacks->set_uart_pin_mux("UART1", "UART");

  // Enable the Tri-State
  set_pin_direction(214, "out");
  set_pin_val(214, 1);

  return 0;
}

static struct hw_module_methods_t hal_module_methods = {};

peripheral_io_module_t HAL_MODULE_INFO_SYM = {
    .common =
        {
            .tag = HARDWARE_MODULE_TAG,
            .module_api_version = 0,
            .hal_api_version = HARDWARE_HAL_API_VERSION,
            .id = PERIPHERAL_IO_HARDWARE_MODULE_ID,
            .name = "periperal IO HAL",
            .author = "The Android Open Source Project",
            .methods = &hal_module_methods,
        },
    .register_devices = register_device,
};