// SPDX-License-Identifier: GPL-2.0-or-later

/***************************************************************************
 *   Copyright (C) 2011-2013 by Martin Schmoelzer                          *
 *   <martin.schmoelzer@student.tuwien.ac.at>                              *
 ***************************************************************************/

/**
 * @file
 * Defines USB descriptors, interrupt routines and helper functions.
 * To minimize code size, we make the following assumptions:
 *  - The OpenULINK has exactly one configuration
 *  - and exactly one alternate setting
 *
 * Therefore, we do not have to support the Set Configuration USB request.
 */

#include "usb.h"
#include "delay.h"
#include "io.h"

/* Also update external declarations in "include/usb.h" if making changes to
 * these variables! */
volatile bool EP2_out;
volatile bool EP2_in;

volatile __xdata __at 0x7FE8 struct setup_data setup_data;

/* Define number of endpoints (except Control Endpoint 0) in a central place.
 * Be sure to include the necessary endpoint descriptors! */
#define NUM_ENDPOINTS 2

__code struct usb_device_descriptor device_descriptor = {
	.bLength =		sizeof(struct usb_device_descriptor),
	.bDescriptorType =	DESCRIPTOR_TYPE_DEVICE,
	.bcdUSB =		0x0110,	/* BCD: 01.00 (Version 1.0 USB spec) */
	.bDeviceClass =		0xFF,	/* 0xFF = vendor-specific */
	.bDeviceSubClass =	0xFF,
	.bDeviceProtocol =	0xFF,
	.bMaxPacketSize0 =	64,
	.idVendor =		0xC251,
	.idProduct =		0x2710,
	.bcdDevice =		0x0100,
	.iManufacturer =	1,
	.iProduct =		2,
	.iSerialNumber =	3,
	.bNumConfigurations =	1
};

/* WARNING: ALL config, interface and endpoint descriptors MUST be adjacent! */

__code struct usb_config_descriptor config_descriptor = {
	.bLength =		sizeof(struct usb_config_descriptor),
	.bDescriptorType =	DESCRIPTOR_TYPE_CONFIGURATION,
	.wTotalLength =		sizeof(struct usb_config_descriptor) +
		sizeof(struct usb_interface_descriptor) +
		(NUM_ENDPOINTS * sizeof(struct usb_endpoint_descriptor)),
	.bNumInterfaces =	1,
	.bConfigurationValue =	1,
	.iConfiguration =	4,	/* String describing this configuration */
	.bmAttributes =		0x80,	/* Only MSB set according to USB spec */
	.MaxPower =		50	/* 100 mA */
};

__code struct usb_interface_descriptor interface_descriptor00 = {
	.bLength = sizeof(struct usb_interface_descriptor),
	.bDescriptorType =	DESCRIPTOR_TYPE_INTERFACE,
	.bInterfaceNumber =	0,
	.bAlternateSetting =	0,
	.bNumEndpoints =	NUM_ENDPOINTS,
	.bInterfaceClass =	0xFF,
	.bInterfaceSubclass =	0xFF,
	.bInterfaceProtocol =	0xFF,
	.iInterface =		0
};

__code struct usb_endpoint_descriptor Bulk_EP2_IN_Endpoint_Descriptor = {
	.bLength =		sizeof(struct usb_endpoint_descriptor),
	.bDescriptorType =	0x05,
	.bEndpointAddress =	(2 | USB_DIR_IN),
	.bmAttributes =		0x02,
	.wMaxPacketSize =	64,
	.bInterval =		0
};

__code struct usb_endpoint_descriptor Bulk_EP2_OUT_Endpoint_Descriptor = {
	.bLength =		sizeof(struct usb_endpoint_descriptor),
	.bDescriptorType =	0x05,
	.bEndpointAddress =	(2 | USB_DIR_OUT),
	.bmAttributes =		0x02,
	.wMaxPacketSize =	64,
	.bInterval =		0
};

__code struct usb_language_descriptor language_descriptor = {
	.bLength =		4,
	.bDescriptorType =	DESCRIPTOR_TYPE_STRING,
	.wLANGID =		{0x0409 /* US English */}
};

__code struct usb_string_descriptor strManufacturer =
	STR_DESCR(9, 'O', 'p', 'e', 'n', 'U', 'L', 'I', 'N', 'K');

__code struct usb_string_descriptor strProduct =
	STR_DESCR(9, 'O', 'p', 'e', 'n', 'U', 'L', 'I', 'N', 'K');

__code struct usb_string_descriptor strSerialNumber =
	STR_DESCR(6, '0', '0', '0', '0', '0', '1');

__code struct usb_string_descriptor strConfigDescr  =
	STR_DESCR(12, 'J', 'T', 'A', 'G', ' ', 'A', 'd', 'a', 'p', 't', 'e', 'r');

/* Table containing pointers to string descriptors */
__code struct usb_string_descriptor *__code en_string_descriptors[4] = {
	&strManufacturer,
	&strProduct,
	&strSerialNumber,
	&strConfigDescr
};

void sudav_isr(void) __interrupt SUDAV_ISR
{
	CLEAR_IRQ();

	usb_handle_setup_data();

	USBIRQ = SUDAVIR;
	EP0CS |= HSNAK;
}

void sof_isr(void)      __interrupt SOF_ISR
{
}
void sutok_isr(void)    __interrupt SUTOK_ISR
{
}
void suspend_isr(void)  __interrupt SUSPEND_ISR
{
}
void usbreset_isr(void) __interrupt USBRESET_ISR
{
}
void ibn_isr(void)      __interrupt IBN_ISR
{
}

void ep0in_isr(void)    __interrupt EP0IN_ISR
{
}
void ep0out_isr(void)   __interrupt EP0OUT_ISR
{
}
void ep1in_isr(void)    __interrupt EP1IN_ISR
{
}
void ep1out_isr(void)   __interrupt EP1OUT_ISR
{
}

/**
 * EP2 IN: called after the transfer from uC->Host has finished: we sent data
 */
void ep2in_isr(void)    __interrupt EP2IN_ISR
{
	EP2_in = 1;

	CLEAR_IRQ();
	IN07IRQ = IN2IR;/* Clear OUT2 IRQ */
}

/**
 * EP2 OUT: called after the transfer from Host->uC has finished: we got data
 */
void ep2out_isr(void)   __interrupt EP2OUT_ISR
{
	EP2_out = 1;

	CLEAR_IRQ();
	OUT07IRQ = OUT2IR;	/* Clear OUT2 IRQ */
}

void ep3in_isr(void)    __interrupt EP3IN_ISR
{
}
void ep3out_isr(void)   __interrupt EP3OUT_ISR
{
}
void ep4in_isr(void)    __interrupt EP4IN_ISR
{
}
void ep4out_isr(void)   __interrupt EP4OUT_ISR
{
}
void ep5in_isr(void)    __interrupt EP5IN_ISR
{
}
void ep5out_isr(void)   __interrupt EP5OUT_ISR
{
}
void ep6in_isr(void)    __interrupt EP6IN_ISR
{
}
void ep6out_isr(void)   __interrupt EP6OUT_ISR
{
}
void ep7in_isr(void)    __interrupt EP7IN_ISR
{
}
void ep7out_isr(void)   __interrupt EP7OUT_ISR
{
}

/**
 * Return the control/status register for an endpoint
 *
 * @param ep endpoint address
 * @return on success: pointer to Control & Status register for endpoint
 *  specified in \a ep
 * @return on failure: NULL
 */
__xdata uint8_t *usb_get_endpoint_cs_reg(uint8_t ep)
{
	/* Mask direction bit */
	uint8_t ep_num = ep & 0x7F;

	switch (ep_num) {
	    case 0:
		    return &EP0CS;
		    break;
	    case 1:
		    return ep & 0x80 ? &IN1CS : &OUT1CS;
		    break;
	    case 2:
		    return ep & 0x80 ? &IN2CS : &OUT2CS;
		    break;
	    case 3:
		    return ep & 0x80 ? &IN3CS : &OUT3CS;
		    break;
	    case 4:
		    return ep & 0x80 ? &IN4CS : &OUT4CS;
		    break;
	    case 5:
		    return ep & 0x80 ? &IN5CS : &OUT5CS;
		    break;
	    case 6:
		    return ep & 0x80 ? &IN6CS : &OUT6CS;
		    break;
	    case 7:
		    return ep & 0x80 ? &IN7CS : &OUT7CS;
		    break;
	}

	return NULL;
}

void usb_reset_data_toggle(uint8_t ep)
{
	/* TOGCTL register:
	   +----+-----+-----+------+-----+-------+-------+-------+
	   | Q  |  S  |  R  |  IO  |  0  |  EP2  |  EP1  |  EP0  |
	   +----+-----+-----+------+-----+-------+-------+-------+

	   To reset data toggle bits, we have to write the endpoint direction (IN/OUT)
	   to the IO bit and the endpoint number to the EP2..EP0 bits. Then, in a
	   separate write cycle, the R bit needs to be set.
	*/
	uint8_t togctl_value = (ep & 0x80 >> 3) | (ep & 0x7);

	/* First step: Write EP number and direction bit */
	TOGCTL = togctl_value;

	/* Second step: Set R bit */
	togctl_value |= TOG_R;
	TOGCTL = togctl_value;
}

/**
 * Handle GET_STATUS request.
 *
 * @return on success: true
 * @return on failure: false
 */
bool usb_handle_get_status(void)
{
	uint8_t *ep_cs;

	switch (setup_data.bmRequestType) {
	    case GS_DEVICE:
			/* Two byte response: Byte 0, Bit 0 = self-powered, Bit 1 = remote wakeup.
			 *                    Byte 1: reserved, reset to zero */
		    IN0BUF[0] = 0;
		    IN0BUF[1] = 0;

			/* Send response */
		    IN0BC = 2;
		    break;
	    case GS_INTERFACE:
			/* Always return two zero bytes according to USB 1.1 spec, p. 191 */
		    IN0BUF[0] = 0;
		    IN0BUF[1] = 0;

			/* Send response */
		    IN0BC = 2;
		    break;
	    case GS_ENDPOINT:
			/* Get stall bit for endpoint specified in low byte of wIndex */
		    ep_cs = usb_get_endpoint_cs_reg(setup_data.wIndex & 0xff);

		    if (*ep_cs & EPSTALL)
			    IN0BUF[0] = 0x01;
		    else
			    IN0BUF[0] = 0x00;

			/* Second byte sent has to be always zero */
		    IN0BUF[1] = 0;

			/* Send response */
		    IN0BC = 2;
		    break;
	    default:
		    return false;
		    break;
	}

	return true;
}

/**
 * Handle CLEAR_FEATURE request.
 *
 * @return on success: true
 * @return on failure: false
 */
bool usb_handle_clear_feature(void)
{
	__xdata uint8_t *ep_cs;

	switch (setup_data.bmRequestType) {
	    case CF_DEVICE:
			/* Clear remote wakeup not supported: stall EP0 */
		    STALL_EP0();
		    break;
	    case CF_ENDPOINT:
		    if (setup_data.wValue == 0) {
				/* Unstall the endpoint specified in wIndex */
			    ep_cs = usb_get_endpoint_cs_reg(setup_data.wIndex);
			    if (!ep_cs)
				    return false;
			    *ep_cs &= ~EPSTALL;
		    } else {
				/* Unsupported feature, stall EP0 */
			    STALL_EP0();
		    }
		    break;
	    default:
			/* Vendor commands... */
	}

	return true;
}

/**
 * Handle SET_FEATURE request.
 *
 * @return on success: true
 * @return on failure: false
 */
bool usb_handle_set_feature(void)
{
	__xdata uint8_t *ep_cs;

	switch (setup_data.bmRequestType) {
	    case SF_DEVICE:
		    if (setup_data.wValue == 2)
			    return true;
		    break;
	    case SF_ENDPOINT:
		    if (setup_data.wValue == 0) {
				/* Stall the endpoint specified in wIndex */
			    ep_cs = usb_get_endpoint_cs_reg(setup_data.wIndex);
			    if (!ep_cs)
				    return false;
			    *ep_cs |= EPSTALL;
		    } else {
				/* Unsupported endpoint feature */
			    return false;
		    }
		    break;
	    default:
			/* Vendor commands... */
		    break;
	}

	return true;
}

/**
 * Handle GET_DESCRIPTOR request.
 *
 * @return on success: true
 * @return on failure: false
 */
bool usb_handle_get_descriptor(void)
{
	__xdata uint8_t descriptor_type;
	__xdata uint8_t descriptor_index;

	descriptor_type = (setup_data.wValue & 0xff00) >> 8;
	descriptor_index = setup_data.wValue & 0x00ff;

	switch (descriptor_type) {
	    case DESCRIPTOR_TYPE_DEVICE:
		    SUDPTRH = HI8(&device_descriptor);
		    SUDPTRL = LO8(&device_descriptor);
		    break;
	    case DESCRIPTOR_TYPE_CONFIGURATION:
		    SUDPTRH = HI8(&config_descriptor);
		    SUDPTRL = LO8(&config_descriptor);
		    break;
	    case DESCRIPTOR_TYPE_STRING:
		    if (setup_data.wIndex == 0) {
				/* Supply language descriptor */
			    SUDPTRH = HI8(&language_descriptor);
			    SUDPTRL = LO8(&language_descriptor);
		    } else if (setup_data.wIndex == 0x0409 /* US English */)   {
				/* Supply string descriptor */
			    SUDPTRH = HI8(en_string_descriptors[descriptor_index - 1]);
			    SUDPTRL = LO8(en_string_descriptors[descriptor_index - 1]);
		    } else
			    return false;
		    break;
	    default:
			/* Unsupported descriptor type */
		    return false;
		    break;
	}

	return true;
}

/**
 * Handle SET_INTERFACE request.
 */
void usb_handle_set_interface(void)
{
	/* Reset Data Toggle */
	usb_reset_data_toggle(USB_DIR_IN  | 2);
	usb_reset_data_toggle(USB_DIR_OUT | 2);

	/* Unstall & clear busy flag of all valid IN endpoints */
	IN2CS = 0 | EPBSY;

	/* Unstall all valid OUT endpoints, reset bytecounts */
	OUT2CS = 0;
	OUT2BC = 0;
}

/**
 * Handle the arrival of a USB Control Setup Packet.
 */
void usb_handle_setup_data(void)
{
	switch (setup_data.bRequest) {
	    case GET_STATUS:
		    if (!usb_handle_get_status())
			    STALL_EP0();
		    break;
	    case CLEAR_FEATURE:
		    if (!usb_handle_clear_feature())
			    STALL_EP0();
		    break;
	    case 2: case 4:
			/* Reserved values */
		    STALL_EP0();
		    break;
	    case SET_FEATURE:
		    if (!usb_handle_set_feature())
			    STALL_EP0();
		    break;
	    case SET_ADDRESS:
			/* Handled by USB core */
		    break;
	    case SET_DESCRIPTOR:
			/* Set Descriptor not supported. */
		    STALL_EP0();
		    break;
	    case GET_DESCRIPTOR:
		    if (!usb_handle_get_descriptor())
			    STALL_EP0();
		    break;
	    case GET_CONFIGURATION:
			/* OpenULINK has only one configuration, return its index */
		    IN0BUF[0] = config_descriptor.bConfigurationValue;
		    IN0BC = 1;
		    break;
	    case SET_CONFIGURATION:
			/* OpenULINK has only one configuration -> nothing to do */
		    break;
	    case GET_INTERFACE:
			/* OpenULINK only has one interface, return its number */
		    IN0BUF[0] = interface_descriptor00.bInterfaceNumber;
		    IN0BC = 1;
		    break;
	    case SET_INTERFACE:
		    usb_handle_set_interface();
		    break;
	    case SYNCH_FRAME:
			/* Isochronous endpoints not used -> nothing to do */
		    break;
	    default:
			/* Any other requests: do nothing */
		    break;
	}
}

/**
 * USB initialization. Configures USB interrupts, endpoints and performs
 * ReNumeration.
 */
void usb_init(void)
{
	/* Mark endpoint 2 IN & OUT as valid */
	IN07VAL  = IN2VAL;
	OUT07VAL = OUT2VAL;

	/* Make sure no isochronous endpoints are marked valid */
	INISOVAL  = 0;
	OUTISOVAL = 0;

	/* Disable isochronous endpoints. This makes the isochronous data buffers
	 * available as 8051 XDATA memory at address 0x2000 - 0x27FF */
	ISOCTL = ISODISAB;

	/* Enable USB Autovectoring */
	USBBAV |= AVEN;

	/* Enable SUDAV interrupt */
	USBIEN |= SUDAVIE;

	/* Enable EP2 OUT & IN interrupts */
	OUT07IEN = OUT2IEN;
	IN07IEN  = IN2IEN;

	/* Enable USB interrupt (EIE register) */
	EUSB = 1;

	/* Perform ReNumeration */
	USBCS = DISCON | RENUM;
	delay_ms(200);
	USBCS = DISCOE | RENUM;
}