/*
 * USB loopback function
 *
 * Copyright (c) 2018 Phytec Messtechnik GmbH
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <zephyr/init.h>

#include <zephyr/sys/byteorder.h>
#include <zephyr/usb/usb_device.h>
#include <usb_descriptor.h>

#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(usb_loopback, CONFIG_USB_DEVICE_LOG_LEVEL);

#define LOOPBACK_OUT_EP_ADDR		0x01
#define LOOPBACK_IN_EP_ADDR		0x81

#define LOOPBACK_OUT_EP_IDX		0
#define LOOPBACK_IN_EP_IDX		1

static uint8_t loopback_buf[1024];
BUILD_ASSERT(sizeof(loopback_buf) == CONFIG_USB_REQUEST_BUFFER_SIZE);

/* usb.rst config structure start */
struct usb_loopback_config {
	struct usb_if_descriptor if0;
	struct usb_ep_descriptor if0_out_ep;
	struct usb_ep_descriptor if0_in_ep;
} __packed;

USBD_CLASS_DESCR_DEFINE(primary, 0) struct usb_loopback_config loopback_cfg = {
	/* Interface descriptor 0 */
	.if0 = {
		.bLength = sizeof(struct usb_if_descriptor),
		.bDescriptorType = USB_DESC_INTERFACE,
		.bInterfaceNumber = 0,
		.bAlternateSetting = 0,
		.bNumEndpoints = 2,
		.bInterfaceClass = USB_BCC_VENDOR,
		.bInterfaceSubClass = 0,
		.bInterfaceProtocol = 0,
		.iInterface = 0,
	},

	/* Data Endpoint OUT */
	.if0_out_ep = {
		.bLength = sizeof(struct usb_ep_descriptor),
		.bDescriptorType = USB_DESC_ENDPOINT,
		.bEndpointAddress = LOOPBACK_OUT_EP_ADDR,
		.bmAttributes = USB_DC_EP_BULK,
		.wMaxPacketSize = sys_cpu_to_le16(CONFIG_LOOPBACK_BULK_EP_MPS),
		.bInterval = 0x00,
	},

	/* Data Endpoint IN */
	.if0_in_ep = {
		.bLength = sizeof(struct usb_ep_descriptor),
		.bDescriptorType = USB_DESC_ENDPOINT,
		.bEndpointAddress = LOOPBACK_IN_EP_ADDR,
		.bmAttributes = USB_DC_EP_BULK,
		.wMaxPacketSize = sys_cpu_to_le16(CONFIG_LOOPBACK_BULK_EP_MPS),
		.bInterval = 0x00,
	},
};
/* usb.rst config structure end */

static void loopback_out_cb(uint8_t ep, enum usb_dc_ep_cb_status_code ep_status)
{
	uint32_t bytes_to_read;

	usb_read(ep, NULL, 0, &bytes_to_read);
	LOG_DBG("ep 0x%x, bytes to read %d ", ep, bytes_to_read);
	usb_read(ep, loopback_buf, bytes_to_read, NULL);
}

static void loopback_in_cb(uint8_t ep, enum usb_dc_ep_cb_status_code ep_status)
{
	if (usb_write(ep, loopback_buf, CONFIG_LOOPBACK_BULK_EP_MPS, NULL)) {
		LOG_DBG("ep 0x%x", ep);
	}
}

/* usb.rst endpoint configuration start */
static struct usb_ep_cfg_data ep_cfg[] = {
	{
		.ep_cb = loopback_out_cb,
		.ep_addr = LOOPBACK_OUT_EP_ADDR,
	},
	{
		.ep_cb = loopback_in_cb,
		.ep_addr = LOOPBACK_IN_EP_ADDR,
	},
};
/* usb.rst endpoint configuration end */

static void loopback_status_cb(struct usb_cfg_data *cfg,
			       enum usb_dc_status_code status,
			       const uint8_t *param)
{
	ARG_UNUSED(cfg);

	switch (status) {
	case USB_DC_INTERFACE:
		loopback_in_cb(ep_cfg[LOOPBACK_IN_EP_IDX].ep_addr, 0);
		LOG_DBG("USB interface configured");
		break;
	case USB_DC_SET_HALT:
		LOG_DBG("Set Feature ENDPOINT_HALT");
		break;
	case USB_DC_CLEAR_HALT:
		LOG_DBG("Clear Feature ENDPOINT_HALT");
		if (*param == ep_cfg[LOOPBACK_IN_EP_IDX].ep_addr) {
			loopback_in_cb(ep_cfg[LOOPBACK_IN_EP_IDX].ep_addr, 0);
		}
		break;
	default:
		break;
	}
}

/* usb.rst vendor handler start */
static int loopback_vendor_handler(struct usb_setup_packet *setup,
				   int32_t *len, uint8_t **data)
{
	LOG_DBG("Class request: bRequest 0x%x bmRequestType 0x%x len %d",
		setup->bRequest, setup->bmRequestType, *len);

	if (setup->RequestType.recipient != USB_REQTYPE_RECIPIENT_DEVICE) {
		return -ENOTSUP;
	}

	if (usb_reqtype_is_to_device(setup) &&
	    setup->bRequest == 0x5b) {
		LOG_DBG("Host-to-Device, data %p", *data);
		/*
		 * Copy request data in loopback_buf buffer and reuse
		 * it later in control device-to-host transfer.
		 */
		memcpy(loopback_buf, *data,
		       MIN(sizeof(loopback_buf), setup->wLength));
		return 0;
	}

	if ((usb_reqtype_is_to_host(setup)) &&
	    (setup->bRequest == 0x5c)) {
		LOG_DBG("Device-to-Host, wLength %d, data %p",
			setup->wLength, *data);
		*data = loopback_buf;
		*len = MIN(sizeof(loopback_buf), setup->wLength);
		return 0;
	}

	return -ENOTSUP;
}
/* usb.rst vendor handler end */

static void loopback_interface_config(struct usb_desc_header *head,
				      uint8_t bInterfaceNumber)
{
	ARG_UNUSED(head);

	loopback_cfg.if0.bInterfaceNumber = bInterfaceNumber;
}

/* usb.rst device config data start */
USBD_DEFINE_CFG_DATA(loopback_config) = {
	.usb_device_description = NULL,
	.interface_config = loopback_interface_config,
	.interface_descriptor = &loopback_cfg.if0,
	.cb_usb_status = loopback_status_cb,
	.interface = {
		.class_handler = NULL,
		.custom_handler = NULL,
		.vendor_handler = loopback_vendor_handler,
	},
	.num_endpoints = ARRAY_SIZE(ep_cfg),
	.endpoint = ep_cfg,
};
/* usb.rst device config data end */