/* W5500 Stand-alone Ethernet Controller with SPI
 *
 * Copyright (c) 2020 Linumiz
 * Author: Parthiban Nallathambi <parthiban@linumiz.com>
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#define DT_DRV_COMPAT	wiznet_w5500

#include <logging/log.h>
LOG_MODULE_REGISTER(eth_w5500, CONFIG_ETHERNET_LOG_LEVEL);

#include <zephyr.h>
#include <device.h>
#include <string.h>
#include <errno.h>
#include <drivers/gpio.h>
#include <drivers/spi.h>
#include <net/net_pkt.h>
#include <net/net_if.h>
#include <net/ethernet.h>
#include <ethernet/eth_stats.h>

#include "eth.h"
#include "eth_w5500_priv.h"

#define WIZNET_OUI_B0	0x00
#define WIZNET_OUI_B1	0x08
#define WIZNET_OUI_B2	0xdc

#define W5500_SPI_BLOCK_SELECT(addr)	(((addr) >> 16) & 0x1f)
#define W5500_SPI_READ_CONTROL(addr)	(W5500_SPI_BLOCK_SELECT(addr) << 3)
#define W5500_SPI_WRITE_CONTROL(addr)   \
	((W5500_SPI_BLOCK_SELECT(addr) << 3) | BIT(2))

static int w5500_spi_read(const struct device *dev, uint32_t addr,
			  uint8_t *data, uint32_t len)
{
	int ret;
	struct w5500_runtime *ctx = dev->data;
	/* 3 bytes as 0x010203 during command phase */
	uint8_t tmp[len + 3];

	uint8_t cmd[3] = {
		addr >> 8,
		addr,
		W5500_SPI_READ_CONTROL(addr)
	};
	const struct spi_buf tx_buf = {
		.buf = cmd,
		.len = ARRAY_SIZE(cmd),
	};
	const struct spi_buf_set tx = {
		.buffers = &tx_buf,
		.count = 1,
	};
	const struct spi_buf rx_buf = {
		.buf = tmp,
		.len = ARRAY_SIZE(tmp),
	};
	const struct spi_buf_set rx = {
		.buffers = &rx_buf,
		.count = 1,
	};

	ret = spi_transceive(ctx->spi, &ctx->spi_cfg, &tx, &rx);

	if (!ret) {
		/* skip the default dummy 0x010203 */
		memcpy(data, &tmp[3], len);
	}

	return ret;
}

static int w5500_spi_write(const struct device *dev, uint32_t addr,
			   uint8_t *data, uint32_t len)
{
	int ret;
	struct w5500_runtime *ctx = dev->data;
	uint8_t cmd[3] = {
		addr >> 8,
		addr,
		W5500_SPI_WRITE_CONTROL(addr),
	};
	const struct spi_buf tx_buf[2] = {
		{
			.buf = cmd,
			.len = ARRAY_SIZE(cmd),
		},
		{
			.buf = data,
			.len = len,
		},
	};
	const struct spi_buf_set tx = {
		.buffers = tx_buf,
		.count = ARRAY_SIZE(tx_buf),
	};

	ret = spi_write(ctx->spi, &ctx->spi_cfg, &tx);

	return ret;
}

static int w5500_readbuf(const struct device *dev, uint16_t offset, uint8_t *buf,
			 int len)
{
	uint32_t addr;
	int remain = 0;
	int ret;
	const uint32_t mem_start = W5500_Sn_RX_MEM_START;
	const uint16_t mem_size = W5500_RX_MEM_SIZE;

	offset %= mem_size;
	addr = mem_start + offset;

	if (offset + len > mem_size) {
		remain = (offset + len) % mem_size;
		len = mem_size - offset;
	}

	ret = w5500_spi_read(dev, addr, buf, len);
	if (ret || !remain) {
		return ret;
	}

	return w5500_spi_read(dev, mem_start, buf + len, remain);
}

static int w5500_writebuf(const struct device *dev, uint16_t offset, uint8_t *buf,
			  int len)
{
	uint32_t addr;
	int ret = 0;
	int remain = 0;
	const uint32_t mem_start = W5500_Sn_TX_MEM_START;
	const uint32_t mem_size = W5500_TX_MEM_SIZE;

	offset %= mem_size;
	addr = mem_start + offset;

	if (offset + len > mem_size) {
		remain = (offset + len) % mem_size;
		len = mem_size - offset;
	}

	ret = w5500_spi_write(dev, addr, buf, len);
	if (ret || !remain) {
		return ret;
	}

	return w5500_spi_write(dev, mem_start, buf + len, remain);
}

static int w5500_command(const struct device *dev, uint8_t cmd)
{
	uint8_t reg;
	uint64_t end = z_timeout_end_calc(K_MSEC(100));

	w5500_spi_write(dev, W5500_S0_CR, &cmd, 1);
	do {
		int64_t remaining = end - z_tick_get();

		if (remaining <= 0) {
			return -EIO;
		}

		w5500_spi_read(dev, W5500_S0_CR, &reg, 1);

		k_msleep(1);
	} while (reg != 0);

	return 0;
}

static int w5500_tx(const struct device *dev, struct net_pkt *pkt)
{
	struct w5500_runtime *ctx = dev->data;
	uint16_t len = net_pkt_get_len(pkt);
	uint16_t offset;
	uint8_t off[2];
	int ret;

	w5500_spi_read(dev, W5500_S0_TX_WR, off, 2);
	offset = sys_get_be16(off);

	if (net_pkt_read(pkt, ctx->buf, len)) {
		return -EIO;
	}

	ret = w5500_writebuf(dev, offset, ctx->buf, len);
	if (ret < 0) {
		return ret;
	}

	sys_put_be16(offset + len, off);
	w5500_spi_write(dev, W5500_S0_TX_WR, off, 2);

	w5500_command(dev, S0_CR_SEND);
	if (k_sem_take(&ctx->tx_sem, K_MSEC(10))) {
		return -EIO;
	}

	return 0;
}

static void w5500_rx(const struct device *dev)
{
	uint8_t mask = 0;
	uint8_t header[2];
	uint8_t tmp[2];
	uint16_t off;
	uint16_t rx_len;
	uint16_t rx_buf_len;
	uint16_t read_len;
	uint16_t reader;
	struct net_buf *pkt_buf = NULL;
	struct net_pkt *pkt;
	struct w5500_runtime *ctx = dev->data;
	const struct w5500_config *config = dev->config;

	/* disable interrupt */
	w5500_spi_write(dev, W5500_SIMR, &mask, 1);
	w5500_spi_read(dev, W5500_S0_RX_RSR, tmp, 2);
	rx_buf_len = sys_get_be16(tmp);

	if (rx_buf_len == 0) {
		return;
	}

	w5500_spi_read(dev, W5500_S0_RX_RD, tmp, 2);
	off = sys_get_be16(tmp);

	w5500_readbuf(dev, off, header, 2);
	rx_len = sys_get_be16(header) - 2;

	pkt = net_pkt_rx_alloc_with_buffer(ctx->iface, rx_len,
			AF_UNSPEC, 0, K_MSEC(config->timeout));
	if (!pkt) {
		eth_stats_update_errors_rx(ctx->iface);
		return;
	}

	pkt_buf = pkt->buffer;

	read_len = rx_len;
	reader = off + 2;

	do {
		size_t frag_len;
		uint8_t *data_ptr;
		size_t frame_len;

		data_ptr = pkt_buf->data;

		frag_len = net_buf_tailroom(pkt_buf);

		if (read_len > frag_len) {
			frame_len = frag_len;
		} else {
			frame_len = read_len;
		}

		w5500_readbuf(dev, reader, data_ptr, frame_len);
		net_buf_add(pkt_buf, frame_len);
		reader += frame_len;

		read_len -= frame_len;
		pkt_buf = pkt_buf->frags;
	} while (read_len > 0);

	if (net_recv_data(ctx->iface, pkt) < 0) {
		net_pkt_unref(pkt);
	}

	sys_put_be16(off + 2 + rx_len, tmp);
	w5500_spi_write(dev, W5500_S0_RX_RD, tmp, 2);
	w5500_command(dev, S0_CR_RECV);
}

static void w5500_isr(const struct device *dev)
{
	uint8_t ir;
	uint8_t mask = 0;
	struct w5500_runtime *ctx = dev->data;

	while (true) {
		k_sem_take(&ctx->int_sem, K_FOREVER);

		w5500_spi_read(dev, W5500_S0_IR, &ir, 1);
		if (!ir) {
			goto done;
		}

		w5500_spi_write(dev, W5500_S0_IR, &ir, 1);

		if (ir & S0_IR_SENDOK) {
			k_sem_give(&ctx->tx_sem);
			LOG_DBG("TX Done");
		}

		if (ir & S0_IR_RECV) {
			w5500_rx(dev);
		}
done:
		/* enable interrupt */
		mask = IR_S0;
		w5500_spi_write(dev, W5500_SIMR, &mask, 1);
	}
}

static void w5500_iface_init(struct net_if *iface)
{
	const struct device *dev = net_if_get_device(iface);
	struct w5500_runtime *ctx = dev->data;

	net_if_set_link_addr(iface, ctx->mac_addr,
			     sizeof(ctx->mac_addr),
			     NET_LINK_ETHERNET);

	if (!ctx->iface) {
		ctx->iface = iface;
	}

	ethernet_init(iface);
}

static enum ethernet_hw_caps w5500_get_capabilities(const struct device *dev)
{
	ARG_UNUSED(dev);

	return ETHERNET_LINK_10BASE_T | ETHERNET_LINK_100BASE_T
#if defined(CONFIG_NET_PROMISCUOUS_MODE)
		| ETHERNET_PROMISC_MODE
#endif
	;
}

static int w5500_set_config(const struct device *dev,
			    enum ethernet_config_type type,
			    const struct ethernet_config *config)
{
	uint8_t mode;
	uint8_t mr = W5500_S0_MR_MF;

	w5500_spi_read(dev, W5500_S0_MR, &mode, 1);
	if (IS_ENABLED(CONFIG_NET_PROMISCUOUS_MODE) &&
	    type == ETHERNET_CONFIG_TYPE_PROMISC_MODE) {
		if (config->promisc_mode) {
			if (!(mode & BIT(mr)))
				return -EALREADY;
			}

			/* clear */
			WRITE_BIT(mode, mr, 0);
	} else {
		if (mode & BIT(mr)) {
			return -EALREADY;
		}

		/* set */
		WRITE_BIT(mode, mr, 1);
	}

	return w5500_spi_write(dev, W5500_S0_MR, &mode, 1);
}

static int w5500_hw_start(const struct device *dev)
{
	uint8_t mode = S0_MR_MACRAW;
	uint8_t mask = IR_S0;

	w5500_spi_write(dev, W5500_S0_MR, &mode, 1);
	w5500_command(dev, S0_CR_OPEN);

	/* enable interrupt */
	w5500_spi_write(dev, W5500_SIMR, &mask, 1);

	return 0;
}

static int w5500_hw_stop(const struct device *dev)
{
	uint8_t mask = 0;

	/* disable interrupt */
	w5500_spi_write(dev, W5500_SIMR, &mask, 1);
	w5500_command(dev, S0_CR_CLOSE);

	return 0;
}

static struct ethernet_api w5500_api_funcs = {
	.iface_api.init = w5500_iface_init,
	.get_capabilities = w5500_get_capabilities,
	.set_config = w5500_set_config,
	.start = w5500_hw_start,
	.stop = w5500_hw_stop,
	.send = w5500_tx,
};

static int w5500_hw_reset(const struct device *dev)
{
	int ret;
	uint8_t mask = 0;
	uint8_t tmp = MR_RST;

	ret = w5500_spi_write(dev, W5500_MR, &tmp, 1);
	if (ret < 0) {
		return ret;
	}

	k_msleep(5);
	tmp = MR_PB;
	w5500_spi_write(dev, W5500_MR, &tmp, 1);

	/* disable interrupt */
	return w5500_spi_write(dev, W5500_SIMR, &mask, 1);
}

static void w5500_gpio_callback(const struct device *dev,
				struct gpio_callback *cb,
				uint32_t pins)
{
	struct w5500_runtime *ctx =
		CONTAINER_OF(cb, struct w5500_runtime, gpio_cb);

	k_sem_give(&ctx->int_sem);
}

static void w5500_set_macaddr(const struct device *dev)
{
	struct w5500_runtime *ctx = dev->data;

	/* override vendor bytes */
	memset(ctx->mac_addr, '\0', sizeof(ctx->mac_addr));
	ctx->mac_addr[0] = WIZNET_OUI_B0;
	ctx->mac_addr[1] = WIZNET_OUI_B1;
	ctx->mac_addr[2] = WIZNET_OUI_B2;
	if (ctx->generate_mac) {
		ctx->generate_mac(ctx->mac_addr);
	}

	w5500_spi_write(dev, W5500_SHAR, ctx->mac_addr, sizeof(ctx->mac_addr));
}

static void w5500_memory_configure(const struct device *dev)
{
	int i;
	uint8_t mem = 0x10;

	/* Configure RX & TX memory to 16K */
	w5500_spi_write(dev, W5500_Sn_RXMEM_SIZE(0), &mem, 1);
	w5500_spi_write(dev, W5500_Sn_TXMEM_SIZE(0), &mem, 1);

	mem = 0;
	for (i = 1; i < 8; i++) {
		w5500_spi_write(dev, W5500_Sn_RXMEM_SIZE(i), &mem, 1);
		w5500_spi_write(dev, W5500_Sn_TXMEM_SIZE(i), &mem, 1);
	}
}

static void w5500_random_mac(uint8_t *mac_addr)
{
	gen_random_mac(mac_addr, WIZNET_OUI_B0, WIZNET_OUI_B1, WIZNET_OUI_B2);
}

static int w5500_init(const struct device *dev)
{
	int err;
	uint8_t rtr[2];
	const struct w5500_config *config = dev->config;
	struct w5500_runtime *ctx = dev->data;

	ctx->spi_cfg.operation = SPI_WORD_SET(8);
	ctx->spi_cfg.frequency = config->spi_freq;
	ctx->spi_cfg.slave = config->spi_slave;

	ctx->spi = device_get_binding((char *)config->spi_port);
	if (!ctx->spi) {
		LOG_ERR("SPI master port %s not found", config->spi_port);
		return -EINVAL;
	}

#if DT_INST_SPI_DEV_HAS_CS_GPIOS(0)
	ctx->spi_cs.gpio_dev = device_get_binding((char *)config->spi_cs_port);
	if (!ctx->spi_cs.gpio_dev) {
		LOG_ERR("SPI CS port %s not found", config->spi_cs_port);
		return -EINVAL;
	}

	ctx->spi_cs.gpio_pin = config->spi_cs_pin;
	ctx->spi_cs.gpio_dt_flags = config->spi_cs_dt_flags;
	ctx->spi_cfg.cs = &ctx->spi_cs;
#endif

	ctx->gpio = device_get_binding((char *)config->gpio_port);
	if (!ctx->gpio) {
		LOG_ERR("GPIO port %s not found", config->gpio_port);
		return -EINVAL;
	}

	if (gpio_pin_configure(ctx->gpio, config->gpio_pin,
			       GPIO_INPUT | config->gpio_flags)) {
		LOG_ERR("Unable to configure GPIO pin %u", config->gpio_pin);
		return -EINVAL;
	}

	gpio_init_callback(&(ctx->gpio_cb), w5500_gpio_callback,
			   BIT(config->gpio_pin));

	if (gpio_add_callback(ctx->gpio, &(ctx->gpio_cb))) {
		return -EINVAL;
	}

	gpio_pin_interrupt_configure(ctx->gpio,
				     config->gpio_pin,
				     GPIO_INT_EDGE_FALLING);

	ctx->reset = device_get_binding((char *)config->reset_port);
	if (!ctx->reset) {
		LOG_ERR("GPIO port %s not found", config->reset_port);
		return -EINVAL;
	}

	if (gpio_pin_configure(ctx->reset, config->reset_pin,
			       GPIO_OUTPUT | config->reset_flags)) {
		LOG_ERR("Unable to configure GPIO pin %u", config->reset_pin);
		return -EINVAL;
	}

	gpio_pin_set(ctx->reset, DT_INST_GPIO_PIN(0, reset_gpios), 0);
	k_usleep(500);

	err = w5500_hw_reset(dev);
	if (err) {
		LOG_ERR("Reset failed");
		return err;
	}

	w5500_set_macaddr(dev);
	w5500_memory_configure(dev);

	/* check retry time value */
	w5500_spi_read(dev, W5500_RTR, rtr, 2);
	if (sys_get_be16(rtr) != RTR_DEFAULT) {
		LOG_ERR("Unable to read RTR register");
		return -ENODEV;
	}

	k_thread_create(&ctx->thread, ctx->thread_stack,
			CONFIG_ETH_W5500_RX_THREAD_STACK_SIZE,
			(k_thread_entry_t)w5500_isr,
			(void *)dev, NULL, NULL,
			K_PRIO_COOP(CONFIG_ETH_W5500_RX_THREAD_PRIO),
			0, K_NO_WAIT);

	LOG_INF("W5500 Initialized");

	return 0;
}

static struct w5500_runtime w5500_0_runtime = {
	.generate_mac = w5500_random_mac,
	.tx_sem = Z_SEM_INITIALIZER(w5500_0_runtime.tx_sem,
					1,  UINT_MAX),
	.int_sem  = Z_SEM_INITIALIZER(w5500_0_runtime.int_sem,
				      0, UINT_MAX),
};

static const struct w5500_config w5500_0_config = {
	.gpio_port = DT_INST_GPIO_LABEL(0, int_gpios),
	.gpio_pin = DT_INST_GPIO_PIN(0, int_gpios),
	.gpio_flags = DT_INST_GPIO_FLAGS(0, int_gpios),
	.reset_port = DT_INST_GPIO_LABEL(0, reset_gpios),
	.reset_pin = DT_INST_GPIO_PIN(0, reset_gpios),
	.reset_flags = DT_INST_GPIO_FLAGS(0, reset_gpios),
	.spi_port = DT_INST_BUS_LABEL(0),
	.spi_freq  = DT_INST_PROP(0, spi_max_frequency),
	.spi_slave = DT_INST_REG_ADDR(0),
#if DT_INST_SPI_DEV_HAS_CS_GPIOS(0)
	.spi_cs_port = DT_INST_SPI_DEV_CS_GPIOS_LABEL(0),
	.spi_cs_pin = DT_INST_SPI_DEV_CS_GPIOS_PIN(0),
	.spi_cs_dt_flags = DT_INST_SPI_DEV_CS_GPIOS_FLAGS(0),
#endif
	.timeout = CONFIG_ETH_W5500_TIMEOUT,
};

ETH_NET_DEVICE_DT_INST_DEFINE(0,
		    w5500_init, device_pm_control_nop,
		    &w5500_0_runtime, &w5500_0_config,
		    CONFIG_ETH_INIT_PRIORITY, &w5500_api_funcs, NET_ETH_MTU);