// Copyright 2019-2021 Espressif Systems (Shanghai) PTE LTD
//
// 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 <sys/cdefs.h>
#include <stdatomic.h>
#include "esp_log.h"
#include "esp_check.h"
#include "esp_eth.h"
#include "esp_event.h"
#include "esp_heap_caps.h"
#include "esp_timer.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"

static const char *TAG = "esp_eth";

ESP_EVENT_DEFINE_BASE(ETH_EVENT);

typedef enum {
    ESP_ETH_FSM_STOP,
    ESP_ETH_FSM_START
} esp_eth_fsm_t;

/**
 * @brief The Ethernet driver mainly consists of PHY, MAC and
 * the mediator who will handle the request/response from/to MAC, PHY and Users.
 * Ethernet driver adopts an OS timer to check the link status periodically.
 * This structure preserves some important Ethernet attributes (e.g. speed, duplex, link).
 * Function stack_input is the channel which set by user, it will deliver all received packets.
 * If stack_input is set to NULL, then all received packets will be passed to tcp/ip stack.
 * on_lowlevel_init_done and on_lowlevel_deinit_done are callbacks set by user.
 * In the callback, user can do any low level operations (e.g. enable/disable crystal clock).
 */
typedef struct {
    esp_eth_mediator_t mediator;
    esp_eth_phy_t *phy;
    esp_eth_mac_t *mac;
    esp_timer_handle_t check_link_timer;
    uint32_t check_link_period_ms;
    eth_speed_t speed;
    eth_duplex_t duplex;
    eth_link_t link;
    atomic_int ref_count;
    void *priv;
    _Atomic esp_eth_fsm_t fsm;
    esp_err_t (*stack_input)(esp_eth_handle_t eth_handle, uint8_t *buffer, uint32_t length, void *priv);
    esp_err_t (*on_lowlevel_init_done)(esp_eth_handle_t eth_handle);
    esp_err_t (*on_lowlevel_deinit_done)(esp_eth_handle_t eth_handle);
    esp_err_t (*customized_read_phy_reg)(esp_eth_handle_t eth_handle, uint32_t phy_addr, uint32_t phy_reg, uint32_t *reg_value);
    esp_err_t (*customized_write_phy_reg)(esp_eth_handle_t eth_handle, uint32_t phy_addr, uint32_t phy_reg, uint32_t reg_value);
} esp_eth_driver_t;

////////////////////////////////Mediator Functions////////////////////////////////////////////
// Following functions are owned by mediator, which will get invoked by MAC or PHY.
// Mediator functions need to find the right actor (MAC, PHY or user) to perform the operation.
// So in the head of mediator function, we have to get the esp_eth_driver_t pointer.
// With this pointer, we could deliver the task to the real actor (MAC, PHY or user).
// This might sound excessive, but is helpful to separate the PHY with MAC (they can not contact with each other directly).
// For more details, please refer to WiKi. https://en.wikipedia.org/wiki/Mediator_pattern
//////////////////////////////////////////////////////////////////////////////////////////////

static esp_err_t eth_phy_reg_read(esp_eth_mediator_t *eth, uint32_t phy_addr, uint32_t phy_reg, uint32_t *reg_value)
{
    esp_eth_driver_t *eth_driver = __containerof(eth, esp_eth_driver_t, mediator);
    // invoking user customized PHY IO function if necessary
    if (eth_driver->customized_read_phy_reg) {
        return eth_driver->customized_read_phy_reg(eth_driver, phy_addr, phy_reg, reg_value);
    }
    // by default, PHY device is managed by MAC's SMI interface
    esp_eth_mac_t *mac = eth_driver->mac;
    return mac->read_phy_reg(mac, phy_addr, phy_reg, reg_value);
}

static esp_err_t eth_phy_reg_write(esp_eth_mediator_t *eth, uint32_t phy_addr, uint32_t phy_reg, uint32_t reg_value)
{
    esp_eth_driver_t *eth_driver = __containerof(eth, esp_eth_driver_t, mediator);
    // invoking user customized PHY IO function if necessary
    if (eth_driver->customized_write_phy_reg) {
        return eth_driver->customized_write_phy_reg(eth_driver, phy_addr, phy_reg, reg_value);
    }
    // by default, PHY device is managed by MAC's SMI interface
    esp_eth_mac_t *mac = eth_driver->mac;
    return mac->write_phy_reg(mac, phy_addr, phy_reg, reg_value);
}

static esp_err_t eth_stack_input(esp_eth_mediator_t *eth, uint8_t *buffer, uint32_t length)
{
    esp_eth_driver_t *eth_driver = __containerof(eth, esp_eth_driver_t, mediator);
    if (eth_driver->stack_input) {
        return eth_driver->stack_input((esp_eth_handle_t)eth_driver, buffer, length, eth_driver->priv);
    }
    // No stack input path has been installed, just drop the incoming packets
    free(buffer);
    return ESP_OK;
}

static esp_err_t eth_on_state_changed(esp_eth_mediator_t *eth, esp_eth_state_t state, void *args)
{
    esp_err_t ret = ESP_OK;
    esp_eth_driver_t *eth_driver = __containerof(eth, esp_eth_driver_t, mediator);
    esp_eth_mac_t *mac = eth_driver->mac;
    switch (state) {
    case ETH_STATE_LLINIT: {
        if (eth_driver->on_lowlevel_init_done) {
            ESP_GOTO_ON_ERROR(eth_driver->on_lowlevel_init_done(eth_driver), err, TAG, "extra lowlevel init failed");
        }
        break;
    }
    case ETH_STATE_DEINIT: {
        if (eth_driver->on_lowlevel_deinit_done) {
            ESP_GOTO_ON_ERROR(eth_driver->on_lowlevel_deinit_done(eth_driver), err, TAG, "extra lowlevel deinit failed");
        }
        break;
    }
    case ETH_STATE_LINK: {
        eth_link_t link = (eth_link_t)args;
        ESP_GOTO_ON_ERROR(mac->set_link(mac, link), err, TAG, "ethernet mac set link failed");
        eth_driver->link = link;
        if (link == ETH_LINK_UP) {
            ESP_GOTO_ON_ERROR(esp_event_post(ETH_EVENT, ETHERNET_EVENT_CONNECTED, &eth_driver, sizeof(esp_eth_driver_t *), 0), err,
                              TAG, "send ETHERNET_EVENT_CONNECTED event failed");
        } else if (link == ETH_LINK_DOWN) {
            ESP_GOTO_ON_ERROR(esp_event_post(ETH_EVENT, ETHERNET_EVENT_DISCONNECTED, &eth_driver, sizeof(esp_eth_driver_t *), 0), err,
                              TAG, "send ETHERNET_EVENT_DISCONNECTED event failed");
        }
        break;
    }
    case ETH_STATE_SPEED: {
        eth_speed_t speed = (eth_speed_t)args;
        ESP_GOTO_ON_ERROR(mac->set_speed(mac, speed), err, TAG, "ethernet mac set speed failed");
        eth_driver->speed = speed;
        break;
    }
    case ETH_STATE_DUPLEX: {
        eth_duplex_t duplex = (eth_duplex_t)args;
        ESP_GOTO_ON_ERROR(mac->set_duplex(mac, duplex), err, TAG, "ethernet mac set duplex failed");
        eth_driver->duplex = duplex;
        break;
    }
    case ETH_STATE_PAUSE: {
        uint32_t peer_pause_ability = (uint32_t)args;
        ESP_GOTO_ON_ERROR(mac->set_peer_pause_ability(mac, peer_pause_ability), err, TAG, "ethernet mac set peer pause ability failed");
        break;
    }
    default:
        ESP_GOTO_ON_FALSE(false, ESP_ERR_INVALID_ARG, err, TAG, "unknown ethernet state: %d", state);
        break;
    }
err:
    return ret;
}

static void eth_check_link_timer_cb(void *args)
{
    esp_eth_driver_t *eth_driver = (esp_eth_driver_t *)args;
    esp_eth_phy_t *phy = eth_driver->phy;
    phy->get_link(phy);
}

////////////////////////////////User face APIs////////////////////////////////////////////////
// User has to pass the handle of Ethernet driver to each API.
// Different Ethernet driver instance is identified with a unique handle.
// It's helpful for us to support multiple Ethernet port on ESP32.
//////////////////////////////////////////////////////////////////////////////////////////////

esp_err_t esp_eth_driver_install(const esp_eth_config_t *config, esp_eth_handle_t *out_hdl)
{
    esp_err_t ret = ESP_OK;
    esp_eth_mac_t *mac = NULL;
    esp_eth_phy_t *phy = NULL;
    esp_eth_driver_t *eth_driver = NULL;
    ESP_GOTO_ON_FALSE(config && out_hdl, ESP_ERR_INVALID_ARG, err, TAG, "invalid argument");
    mac = config->mac;
    phy = config->phy;
    ESP_GOTO_ON_FALSE(mac && phy, ESP_ERR_INVALID_ARG, err, TAG, "can't set eth->mac or eth->phy to null");
    // eth_driver contains an atomic variable, which should not be put in PSRAM
    eth_driver = heap_caps_calloc(1, sizeof(esp_eth_driver_t), MALLOC_CAP_INTERNAL | MALLOC_CAP_8BIT);
    ESP_GOTO_ON_FALSE(eth_driver, ESP_ERR_NO_MEM, err, TAG, "no mem for eth_driver");
    const esp_timer_create_args_t check_link_timer_args = {
        .callback = eth_check_link_timer_cb,
        .name = "eth_link_timer",
        .arg = eth_driver,
        .skip_unhandled_events = true
    };
    ESP_GOTO_ON_ERROR(esp_timer_create(&check_link_timer_args, &eth_driver->check_link_timer), err, TAG, "create link timer failed");
    atomic_init(&eth_driver->ref_count, 1);
    atomic_init(&eth_driver->fsm, ESP_ETH_FSM_STOP);
    eth_driver->mac = mac;
    eth_driver->phy = phy;
    eth_driver->link = ETH_LINK_DOWN;
    eth_driver->duplex = ETH_DUPLEX_HALF;
    eth_driver->speed = ETH_SPEED_10M;
    eth_driver->stack_input = config->stack_input;
    eth_driver->on_lowlevel_init_done = config->on_lowlevel_init_done;
    eth_driver->on_lowlevel_deinit_done = config->on_lowlevel_deinit_done;
    eth_driver->check_link_period_ms = config->check_link_period_ms;
    eth_driver->customized_read_phy_reg = config->read_phy_reg;
    eth_driver->customized_write_phy_reg = config->write_phy_reg;
    eth_driver->mediator.phy_reg_read = eth_phy_reg_read;
    eth_driver->mediator.phy_reg_write = eth_phy_reg_write;
    eth_driver->mediator.stack_input = eth_stack_input;
    eth_driver->mediator.on_state_changed = eth_on_state_changed;
    // set mediator for both mac and phy object, so that mac and phy are connected to each other via mediator
    mac->set_mediator(mac, &eth_driver->mediator);
    phy->set_mediator(phy, &eth_driver->mediator);
    // for PHY whose internal PLL has been configured to generate RMII clock, but is put in reset state during power up,
    // we need to deasseert the reset GPIO of PHY device first, ensure the RMII is clocked out from PHY
    phy->reset_hw(phy);
    // init MAC first, so that MAC can generate the correct SMI signals
    ESP_GOTO_ON_ERROR(mac->init(mac), err, TAG, "init mac failed");
    ESP_GOTO_ON_ERROR(phy->init(phy), err, TAG, "init phy failed");
    ESP_LOGD(TAG, "new ethernet driver @%p", eth_driver);
    *out_hdl = eth_driver;

    // for backward compatible to 4.0, and will get removed in 5.0
#if CONFIG_ESP_NETIF_TCPIP_ADAPTER_COMPATIBLE_LAYER
    extern esp_err_t tcpip_adapter_compat_start_eth(void *eth_driver);
    tcpip_adapter_compat_start_eth(eth_driver);
#endif

    return ESP_OK;
err:
    if (eth_driver) {
        if (eth_driver->check_link_timer) {
            esp_timer_delete(eth_driver->check_link_timer);
        }
        free(eth_driver);
    }
    return ret;
}

esp_err_t esp_eth_driver_uninstall(esp_eth_handle_t hdl)
{
    esp_err_t ret = ESP_OK;
    esp_eth_driver_t *eth_driver = (esp_eth_driver_t *)hdl;
    ESP_GOTO_ON_FALSE(eth_driver, ESP_ERR_INVALID_ARG, err, TAG, "invalid argument");
    // check if driver has stopped
    esp_eth_fsm_t expected_fsm = ESP_ETH_FSM_STOP;
    ESP_GOTO_ON_FALSE(atomic_compare_exchange_strong(&eth_driver->fsm, &expected_fsm, ESP_ETH_FSM_STOP),
                      ESP_ERR_INVALID_STATE, err, TAG, "driver not stopped yet");
    // don't uninstall driver unless there's only one reference
    int expected_ref_count = 1;
    ESP_GOTO_ON_FALSE(atomic_compare_exchange_strong(&eth_driver->ref_count, &expected_ref_count, 0),
                      ESP_ERR_INVALID_STATE, err, TAG, "%d ethernet reference in use", expected_ref_count);
    esp_eth_mac_t *mac = eth_driver->mac;
    esp_eth_phy_t *phy = eth_driver->phy;
    ESP_GOTO_ON_ERROR(esp_timer_delete(eth_driver->check_link_timer), err, TAG, "delete link timer failed");
    ESP_GOTO_ON_ERROR(phy->deinit(phy), err, TAG, "deinit phy failed");
    ESP_GOTO_ON_ERROR(mac->deinit(mac), err, TAG, "deinit mac failed");
    free(eth_driver);
err:
    return ret;
}

esp_err_t esp_eth_start(esp_eth_handle_t hdl)
{
    esp_err_t ret = ESP_OK;
    esp_eth_driver_t *eth_driver = (esp_eth_driver_t *)hdl;
    ESP_GOTO_ON_FALSE(eth_driver, ESP_ERR_INVALID_ARG, err, TAG, "ethernet driver handle can't be null");
    esp_eth_phy_t *phy = eth_driver->phy;
    // check if driver has stopped
    esp_eth_fsm_t expected_fsm = ESP_ETH_FSM_STOP;
    ESP_GOTO_ON_FALSE(atomic_compare_exchange_strong(&eth_driver->fsm, &expected_fsm, ESP_ETH_FSM_START),
                      ESP_ERR_INVALID_STATE, err, TAG, "driver started already");
    // reset PHY device, to put it back to LINK_DOWN state
    ESP_GOTO_ON_ERROR(phy->reset(phy), err, TAG, "reset phy failed");
    ESP_GOTO_ON_ERROR(esp_event_post(ETH_EVENT, ETHERNET_EVENT_START, &eth_driver, sizeof(esp_eth_driver_t *), 0),
                      err, TAG, "send ETHERNET_EVENT_START event failed");
    ESP_GOTO_ON_ERROR(esp_timer_start_periodic(eth_driver->check_link_timer, eth_driver->check_link_period_ms * 1000),
                      err, TAG, "start link timer failed");
err:
    return ret;
}

esp_err_t esp_eth_stop(esp_eth_handle_t hdl)
{
    esp_err_t ret = ESP_OK;
    esp_eth_driver_t *eth_driver = (esp_eth_driver_t *)hdl;
    ESP_GOTO_ON_FALSE(eth_driver, ESP_ERR_INVALID_ARG, err, TAG, "ethernet driver handle can't be null");
    esp_eth_mac_t *mac = eth_driver->mac;
    // check if driver has started
    esp_eth_fsm_t expected_fsm = ESP_ETH_FSM_START;
    ESP_GOTO_ON_FALSE(atomic_compare_exchange_strong(&eth_driver->fsm, &expected_fsm, ESP_ETH_FSM_STOP),
                      ESP_ERR_INVALID_STATE, err, TAG, "driver not started yet");
    ESP_GOTO_ON_ERROR(esp_timer_stop(eth_driver->check_link_timer), err, TAG, "stop link timer failed");
    ESP_GOTO_ON_ERROR(mac->stop(mac), err, TAG, "stop mac failed");
    ESP_GOTO_ON_ERROR(esp_event_post(ETH_EVENT, ETHERNET_EVENT_STOP, &eth_driver, sizeof(esp_eth_driver_t *), 0),
                      err, TAG, "send ETHERNET_EVENT_STOP event failed");
err:
    return ret;
}

esp_err_t esp_eth_update_input_path(
    esp_eth_handle_t hdl,
    esp_err_t (*stack_input)(esp_eth_handle_t hdl, uint8_t *buffer, uint32_t length, void *priv),
    void *priv)
{
    esp_err_t ret = ESP_OK;
    esp_eth_driver_t *eth_driver = (esp_eth_driver_t *)hdl;
    ESP_GOTO_ON_FALSE(eth_driver, ESP_ERR_INVALID_ARG, err, TAG, "ethernet driver handle can't be null");
    eth_driver->priv = priv;
    eth_driver->stack_input = stack_input;
err:
    return ret;
}

esp_err_t esp_eth_transmit(esp_eth_handle_t hdl, void *buf, size_t length)
{
    esp_err_t ret = ESP_OK;
    esp_eth_driver_t *eth_driver = (esp_eth_driver_t *)hdl;
    ESP_GOTO_ON_FALSE(buf, ESP_ERR_INVALID_ARG, err, TAG, "can't set buf to null");
    ESP_GOTO_ON_FALSE(length, ESP_ERR_INVALID_ARG, err, TAG, "buf length can't be zero");
    ESP_GOTO_ON_FALSE(eth_driver, ESP_ERR_INVALID_ARG, err, TAG, "ethernet driver handle can't be null");
    esp_eth_mac_t *mac = eth_driver->mac;
    ret = mac->transmit(mac, buf, length);
err:
    return ret;
}

esp_err_t esp_eth_receive(esp_eth_handle_t hdl, uint8_t *buf, uint32_t *length)
{
    esp_err_t ret = ESP_OK;
    esp_eth_driver_t *eth_driver = (esp_eth_driver_t *)hdl;
    ESP_GOTO_ON_FALSE(buf && length, ESP_ERR_INVALID_ARG, err, TAG, "can't set buf and length to null");
    ESP_GOTO_ON_FALSE(*length > 60, ESP_ERR_INVALID_ARG, err, TAG, "length can't be less than 60");
    ESP_GOTO_ON_FALSE(eth_driver, ESP_ERR_INVALID_ARG, err, TAG, "ethernet driver handle can't be null");
    esp_eth_mac_t *mac = eth_driver->mac;
    ret = mac->receive(mac, buf, length);
err:
    return ret;
}

esp_err_t esp_eth_ioctl(esp_eth_handle_t hdl, esp_eth_io_cmd_t cmd, void *data)
{
    esp_err_t ret = ESP_OK;
    esp_eth_driver_t *eth_driver = (esp_eth_driver_t *)hdl;
    ESP_GOTO_ON_FALSE(eth_driver, ESP_ERR_INVALID_ARG, err, TAG, "ethernet driver handle can't be null");
    esp_eth_mac_t *mac = eth_driver->mac;
    esp_eth_phy_t *phy = eth_driver->phy;
    switch (cmd) {
    case ETH_CMD_S_MAC_ADDR:
        ESP_GOTO_ON_FALSE(data, ESP_ERR_INVALID_ARG, err, TAG, "can't set mac addr to null");
        ESP_GOTO_ON_ERROR(mac->set_addr(mac, (uint8_t *)data), err, TAG, "set mac address failed");
        break;
    case ETH_CMD_G_MAC_ADDR:
        ESP_GOTO_ON_FALSE(data, ESP_ERR_INVALID_ARG, err, TAG, "no mem to store mac addr");
        ESP_GOTO_ON_ERROR(mac->get_addr(mac, (uint8_t *)data), err, TAG, "get mac address failed");
        break;
    case ETH_CMD_S_PHY_ADDR:
        ESP_GOTO_ON_FALSE(data, ESP_ERR_INVALID_ARG, err, TAG, "can't set phy addr to null");
        ESP_GOTO_ON_ERROR(phy->set_addr(phy, (uint32_t)data), err, TAG, "set phy address failed");
        break;
    case ETH_CMD_G_PHY_ADDR:
        ESP_GOTO_ON_FALSE(data, ESP_ERR_INVALID_ARG, err, TAG, "no mem to store phy addr");
        ESP_GOTO_ON_ERROR(phy->get_addr(phy, (uint32_t *)data), err, TAG, "get phy address failed");
        break;
    case ETH_CMD_G_SPEED:
        ESP_GOTO_ON_FALSE(data, ESP_ERR_INVALID_ARG, err, TAG, "no mem to store speed value");
        *(eth_speed_t *)data = eth_driver->speed;
        break;
    case ETH_CMD_S_PROMISCUOUS:
        ESP_GOTO_ON_ERROR(mac->set_promiscuous(mac, (bool)data), err, TAG, "set promiscuous mode failed");
        break;
    case ETH_CMD_S_FLOW_CTRL:
        ESP_GOTO_ON_ERROR(mac->enable_flow_ctrl(mac, (bool)data), err, TAG, "enable mac flow control failed");
        ESP_GOTO_ON_ERROR(phy->advertise_pause_ability(phy, (uint32_t)data), err, TAG, "phy advertise pause ability failed");
        break;
    case ETH_CMD_G_DUPLEX_MODE:
        ESP_GOTO_ON_FALSE(data, ESP_ERR_INVALID_ARG, err, TAG, "no mem to store duplex value");
        *(eth_duplex_t *)data = eth_driver->duplex;
        break;
    default:
        ESP_GOTO_ON_FALSE(false, ESP_ERR_INVALID_ARG, err, TAG, "unknown io command: %d", cmd);
        break;
    }
err:
    return ret;
}

esp_err_t esp_eth_increase_reference(esp_eth_handle_t hdl)
{
    esp_err_t ret = ESP_OK;
    esp_eth_driver_t *eth_driver = (esp_eth_driver_t *)hdl;
    ESP_GOTO_ON_FALSE(eth_driver, ESP_ERR_INVALID_ARG, err, TAG, "ethernet driver handle can't be null");
    atomic_fetch_add(&eth_driver->ref_count, 1);
err:
    return ret;
}

esp_err_t esp_eth_decrease_reference(esp_eth_handle_t hdl)
{
    esp_err_t ret = ESP_OK;
    esp_eth_driver_t *eth_driver = (esp_eth_driver_t *)hdl;
    ESP_GOTO_ON_FALSE(eth_driver, ESP_ERR_INVALID_ARG, err, TAG, "ethernet driver handle can't be null");
    atomic_fetch_sub(&eth_driver->ref_count, 1);
err:
    return ret;
}