/*
	LPCUSB, an USB device driver for LPC microcontrollers	
	Copyright (C) 2006 Bertrik Sikken (bertrik@sikken.nl)

	This library is free software; you can redistribute it and/or
	modify it under the terms of the GNU Lesser General Public
	License as published by the Free Software Foundation; either
	version 2.1 of the License, or (at your option) any later version.

	This library is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
	Lesser General Public License for more details.

	You should have received a copy of the GNU Lesser General Public
	License along with this library; if not, write to the Free Software
	Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

/** @file
	USB hardware layer
 */

#include "type.h"
#include "usbdebug.h"
#include "usbhw_lpc.h"
#include "usbapi.h"


#ifdef DEBUG
// comment out the following line if you don't want to use debug LEDs
#define DEBUG_LED
#endif

#ifdef DEBUG_LED
#define DEBUG_LED_ON(x)		IOCLR0 = (1 << x);
#define DEBUG_LED_OFF(x)	IOSET0 = (1 << x);
#define DEBUG_LED_INIT(x)	PINSEL0 &= ~(0x3 << (2*x)); IODIR0 |= (1 << x); DEBUG_LED_OFF(x);
#else
#define DEBUG_LED_INIT(x)	/**< LED initialisation macro */
#define DEBUG_LED_ON(x)		/**< turn LED on */
#define DEBUG_LED_OFF(x)	/**< turn LED off */
#endif

/** Installed device interrupt handler */
static TFnDevIntHandler *_pfnDevIntHandler = NULL;
/** Installed endpoint interrupt handlers */
static TFnEPIntHandler	*_apfnEPIntHandlers[16];
/** Installed frame interrupt handlers */
static TFnFrameHandler	*_pfnFrameHandler = NULL;

/** convert from endpoint address to endpoint index */
#define EP2IDX(bEP)	((((bEP)&0xF)<<1)|(((bEP)&0x80)>>7))
/** convert from endpoint index to endpoint address */
#define IDX2EP(idx)	((((idx)<<7)&0x80)|(((idx)>>1)&0xF))



/**
	Local function to wait for a device interrupt (and clear it)
		
	@param [in]	dwIntr		Interrupts to wait for	
 */
static void Wait4DevInt(U32 dwIntr)
{
	while ((USBDevIntSt & dwIntr) != dwIntr);
	USBDevIntClr = dwIntr;
}


/**
	Local function to send a command to the USB protocol engine
		
	@param [in]	bCmd		Command to send
 */
static void USBHwCmd(U8 bCmd)
{
	// clear CDFULL/CCEMTY
	USBDevIntClr = CDFULL | CCEMTY;
	// write command code
	USBCmdCode = 0x00000500 | (bCmd << 16);
	Wait4DevInt(CCEMTY);
}


/**
	Local function to send a command + data to the USB protocol engine
		
	@param [in]	bCmd		Command to send
	@param [in]	bData		Data to send
 */
static void USBHwCmdWrite(U8 bCmd, U16 bData)
{
	// write command code
	USBHwCmd(bCmd);

	// write command data
	USBCmdCode = 0x00000100 | (bData << 16);
	Wait4DevInt(CCEMTY);
}


/**
	Local function to send a command to the USB protocol engine and read data
		
	@param [in]	bCmd		Command to send

	@return the data
 */
static U8 USBHwCmdRead(U8 bCmd)
{
	// write command code
	USBHwCmd(bCmd);
	
	// get data
	USBCmdCode = 0x00000200 | (bCmd << 16);
	Wait4DevInt(CDFULL);
	return USBCmdData;
}


/**
	'Realizes' an endpoint, meaning that buffer space is reserved for
	it. An endpoint needs to be realised before it can be used.
		
	From experiments, it appears that a USB reset causes USBReEP to
	re-initialise to 3 (= just the control endpoints).
	However, a USB bus reset does not disturb the USBMaxPSize settings.
		
	@param [in]	idx			Endpoint index
	@param [in] wMaxPSize	Maximum packet size for this endpoint
 */
static void USBHwEPRealize(int idx, U16 wMaxPSize)
{
	USBReEP |= (1 << idx);
	USBEpInd = idx;
	USBMaxPSize = wMaxPSize;
	Wait4DevInt(EP_RLZED);
}


/**
	Enables or disables an endpoint
		
	@param [in]	idx		Endpoint index
	@param [in]	fEnable	TRUE to enable, FALSE to disable
 */
static void USBHwEPEnable(int idx, BOOL fEnable)
{
	USBHwCmdWrite(CMD_EP_SET_STATUS | idx, fEnable ? 0 : EP_DA);
}


/**
	Configures an endpoint and enables it
		
	@param [in]	bEP				Endpoint number
	@param [in]	wMaxPacketSize	Maximum packet size for this EP
 */
void USBHwEPConfig(U8 bEP, U16 wMaxPacketSize)
{
	int idx;
	
	idx = EP2IDX(bEP);
	
	// realise EP
	USBHwEPRealize(idx, wMaxPacketSize);

	// enable EP
	USBHwEPEnable(idx, TRUE);
}


/**
	Registers an endpoint event callback
		
	@param [in]	bEP				Endpoint number
	@param [in]	pfnHandler		Callback function
 */
void USBHwRegisterEPIntHandler(U8 bEP, TFnEPIntHandler *pfnHandler)
{
	int idx;
	
	idx = EP2IDX(bEP);

	ASSERT(idx<32);

	/* add handler to list of EP handlers */
	_apfnEPIntHandlers[idx / 2] = pfnHandler;
	
	/* enable EP interrupt */
	USBEpIntEn |= (1 << idx);
	USBDevIntEn |= EP_SLOW;
	
	DBG("Registered handler for EP 0x%x\n", bEP);
}


/**
	Registers an device status callback
		
	@param [in]	pfnHandler	Callback function
 */
void USBHwRegisterDevIntHandler(TFnDevIntHandler *pfnHandler)
{
	_pfnDevIntHandler = pfnHandler;
	
	// enable device interrupt
	USBDevIntEn |= DEV_STAT;

	DBG("Registered handler for device status\n");
}


/**
	Registers the frame callback
		
	@param [in]	pfnHandler	Callback function
 */
void USBHwRegisterFrameHandler(TFnFrameHandler *pfnHandler)
{
	_pfnFrameHandler = pfnHandler;
	
	// enable device interrupt
	USBDevIntEn |= FRAME;

	DBG("Registered handler for frame\n");
}


/**
	Sets the USB address.
		
	@param [in]	bAddr		Device address to set
 */
void USBHwSetAddress(U8 bAddr)
{
	USBHwCmdWrite(CMD_DEV_SET_ADDRESS, DEV_EN | bAddr);
}


/**
	Connects or disconnects from the USB bus
		
	@param [in]	fConnect	If TRUE, connect, otherwise disconnect
 */
void USBHwConnect(BOOL fConnect)
{
	USBHwCmdWrite(CMD_DEV_STATUS, fConnect ? CON : 0);
}


/**
	Enables interrupt on NAK condition
		
	For IN endpoints a NAK is generated when the host wants to read data
	from the device, but none is available in the endpoint buffer.
	For OUT endpoints a NAK is generated when the host wants to write data
	to the device, but the endpoint buffer is still full.
	
	The endpoint interrupt handlers can distinguish regular (ACK) interrupts
	from NAK interrupt by checking the bits in their bEPStatus argument.
	
	@param [in]	bIntBits	Bitmap indicating which NAK interrupts to enable
 */
void USBHwNakIntEnable(U8 bIntBits)
{
	USBHwCmdWrite(CMD_DEV_SET_MODE, bIntBits);
}


/**
	Gets the stalled property of an endpoint
		
	@param [in]	bEP		Endpoint number
			
	@return TRUE if stalled, FALSE if not stalled
 */
BOOL USBHwEPIsStalled(U8 bEP)
{
   	int idx = EP2IDX(bEP);

	return (USBHwCmdRead(CMD_EP_SELECT | idx) & 2);
}


/**
	Sets the stalled property of an endpoint
		
	@param [in]	bEP		Endpoint number
	@param [in]	fStall	TRUE to stall, FALSE to unstall
 */
void USBHwEPStall(U8 bEP, BOOL fStall)
{
	int idx = EP2IDX(bEP);

	USBHwCmdWrite(CMD_EP_SET_STATUS | idx, fStall ? EP_ST : 0);
}


/**
	Writes data to an endpoint buffer
		
	@param [in]	bEP		Endpoint number
	@param [in]	pbBuf	Endpoint data
	@param [in]	iLen	Number of bytes to write
			
	@return TRUE if the data was successfully written or <0 in case of error.
*/
int USBHwEPWrite(U8 bEP, U8 *pbBuf, int iLen)
{
	int idx;
	
	idx = EP2IDX(bEP);
	
//	DBG("<%d", iLen);
//	DBG("<");

	// set write enable for specific endpoint
	USBCtrl = WR_EN | ((bEP & 0xF) << 2);
	
	// set packet length
	USBTxPLen = iLen;
	
	// write data
	while (USBCtrl & WR_EN) {
		USBTxData = (pbBuf[3] << 24) | (pbBuf[2] << 16) | (pbBuf[1] << 8) | pbBuf[0];
		pbBuf += 4;
	}

	// select endpoint and validate buffer
	USBHwCmd(CMD_EP_SELECT | idx);
	USBHwCmd(CMD_EP_VALIDATE_BUFFER);
	
	return iLen;
}


/**
	Reads data from an endpoint buffer
		
	@param [in]	bEP		Endpoint number
	@param [in]	pbBuf	Endpoint data
	@param [in]	iMaxLen	Maximum number of bytes to read
			
	@return the number of bytes available in the EP (possibly more than iMaxLen),
	or <0 in case of error.
 */
int USBHwEPRead(U8 bEP, U8 *pbBuf, int iMaxLen)
{
	int i, idx;
	U32	dwData, dwLen;
	
	idx = EP2IDX(bEP);
	
	// set read enable bit for specific endpoint
	USBCtrl = RD_EN | ((bEP & 0xF) << 2);
	
	// wait for PKT_RDY
	do {
		dwLen = USBRxPLen;
	} while ((dwLen & PKT_RDY) == 0);
	
	// packet valid?
	if ((dwLen & DV) == 0) {
		return -1;
	}
	
	// get length
	dwLen &= PKT_LNGTH_MASK;
	
	// get data
	while (USBCtrl & RD_EN) {
		dwData = USBRxData;
		if (pbBuf != NULL) {
			for (i = 0; i < 4; i++) {
				if (iMaxLen-- != 0) {
					*pbBuf++ = dwData & 0xFF;
				}
				dwData >>= 8;
			}
		}
	}

	// select endpoint and clear buffer
	USBHwCmd(CMD_EP_SELECT | idx);
	USBHwCmd(CMD_EP_CLEAR_BUFFER);
	
//	DBG(">%d", dwLen);
//	DBG(">");

	return dwLen;
}


/**
	Sets the 'configured' state.
		
	All registered endpoints are 'realised' and enabled, and the
	'configured' bit is set in the device status register.
		
	@param [in]	fConfigured	If TRUE, configure device, else unconfigure
 */
void USBHwConfigDevice(BOOL fConfigured)
{
	// set configured bit
	USBHwCmdWrite(CMD_DEV_CONFIG, fConfigured ? CONF_DEVICE : 0);
}


/**
	USB interrupt handler
		
	Endpoint interrupts are mapped to the slow interrupt
 */
void USBHwISR(void)
{
	U32	dwStatus, dwEPIntStat;
	U32 dwIntBit;
	U8	bEPStat, bDevStat, bStat;
	int i;
	
	dwStatus = USBDevIntSt;

	// handle device dwStatus interrupts
	if (dwStatus & DEV_STAT) {
DEBUG_LED_ON(8);		
		bDevStat = USBHwCmdRead(CMD_DEV_STATUS);
		if (bDevStat & (CON_CH | SUS_CH | RST)) {
			// convert device status into something HW independent
			bStat = ((bDevStat & CON) ? DEV_STATUS_CONNECT : 0) |
					((bDevStat & SUS) ? DEV_STATUS_SUSPEND : 0) |
					((bDevStat & RST) ? DEV_STATUS_RESET : 0);
			// call handler
			if (_pfnDevIntHandler != NULL) {
				_pfnDevIntHandler(bStat);
			}
		}
		// clear DEV_STAT;
		USBDevIntClr = DEV_STAT;
DEBUG_LED_OFF(8);		
	}
	
	// check endpoint interrupts
	if (dwStatus & EP_SLOW) {
DEBUG_LED_ON(9);		
		dwEPIntStat = USBEpIntSt;
		for (i = 0; i < 32; i++) {
			dwIntBit = (1 << i);
			if (dwEPIntStat & dwIntBit) {
				// clear int (and retrieve status)
				USBEpIntClr = dwIntBit;
				Wait4DevInt(CDFULL);
				bEPStat = USBCmdData;
				// convert EP pipe stat into something HW independent
				bStat = ((bEPStat & EPSTAT_FE) ? EP_STATUS_DATA : 0) |
						((bEPStat & EPSTAT_ST) ? EP_STATUS_STALLED : 0) |
						((bEPStat & EPSTAT_STP) ? EP_STATUS_SETUP : 0) |
						((bEPStat & EPSTAT_EPN) ? EP_STATUS_NACKED : 0) |
						((bEPStat & EPSTAT_PO) ? EP_STATUS_ERROR : 0);
				// call handler
				if (_apfnEPIntHandlers[i / 2] != NULL) {
					_apfnEPIntHandlers[i / 2](IDX2EP(i), bStat);
				}
			}
		}
		// clear EP_SLOW
		USBDevIntClr = EP_SLOW;
DEBUG_LED_OFF(9);
	}
	
	// handle frame interrupt
	if (dwStatus & FRAME) {
DEBUG_LED_ON(10);
		if (_pfnFrameHandler != NULL) {
			_pfnFrameHandler(0);	// implement counter later
		}
		// clear int
		USBDevIntClr = FRAME;
DEBUG_LED_OFF(10);
	}
}



/**
	Initialises the USB hardware
		
	This function assumes that the hardware is connected as shown in
	section 10.1 of the LPC2148 data sheet:
	* P0.31 controls a switch to connect a 1.5k pull-up to D+ if low.
	* P0.23 is connected to USB VCC.
	
	Embedded artists board: make sure to disconnect P0.23 LED as it
	acts as a pull-up and so prevents detection of USB disconnect.
		
	@return TRUE if the hardware was successfully initialised
 */
BOOL USBHwInit(void)
{
	// configure P0.23 for Vbus sense
	PINSEL1 = (PINSEL1 & ~(3 << 14)) | (1 << 14);	// P0.23
	IODIR0 &= ~(1 << 23);
	// configure P0.31 for CONNECT
	PINSEL1 = (PINSEL1 & ~(3 << 30)) | (2 << 30);	// P0.31

	// enable PUSB
	PCONP |= (1 << 31);		
	
	// initialise PLL
	PLL1CON = 1;			// enable PLL
	PLL1CFG = (1 << 5) | 3; // P = 2, M = 4
	PLL1FEED = 0xAA;
	PLL1FEED = 0x55;
	while ((PLL1STAT & (1 << 10)) == 0);

	PLL1CON = 3;			// enable and connect
	PLL1FEED = 0xAA;
	PLL1FEED = 0x55;
	
	// disable/clear all interrupts for now
	USBDevIntEn = 0;
	USBEpIntEn = 0;
	USBDevIntClr = 0xFFFFFFFF;
	USBEpIntClr = 0xFFFFFFFF;

	// setup control endpoints
	USBHwEPConfig(0x00, MAX_PACKET_SIZE0);
	USBHwEPConfig(0x80, MAX_PACKET_SIZE0);
	
	// by default, only ACKs generate interrupts
	USBHwNakIntEnable(0);
	
	// init debug leds
	DEBUG_LED_INIT(8);
	DEBUG_LED_INIT(9);
	DEBUG_LED_INIT(10);

	return TRUE;
}