#include <gint/usb.h>
#include <gint/mpu/usb.h>
#include <gint/clock.h>
#include <gint/dma.h>
#include <gint/defs/util.h>

#include <string.h>

#include <gint/drivers/asyncio.h>
#include "usb_private.h"

#define USB SH7305_USB

//---
// Operations on pipes
//---

/* usb_pipe_configure(): Configure a pipe when opening the connection */
void usb_pipe_configure(int address, endpoint_t const *ep)
{
	/* Maps USB 2.0 transfer types to SH7305 USB module transfer types */
	static uint8_t type_map[4] = {
		0, TYPE_ISOCHRONOUS, TYPE_BULK, TYPE_INTERRUPT };

	if(ep->pipe > 0) {
		/* Set PID to NAK so we can modify the pipe's configuration */
		USB.PIPECTR[ep->pipe-1].PID = PID_NAK;
		usb_while(USB.PIPECTR[ep->pipe-1].PBUSY);
	}

	int type = type_map[ep->dc->bmAttributes & 0x03];
	bool dir_transmitting = (address & 0x80) != 0;
	bool dir_receiving = !dir_transmitting;

	USB.PIPESEL.PIPESEL = ep->pipe;
	USB.PIPECFG.TYPE    = type;
	USB.PIPECFG.BFRE    = dir_receiving;
	/* Enable continuous mode on all bulk transfer pipes
	   TODO: Also make it double mode*/
	USB.PIPECFG.DBLB    = 0;
	USB.PIPECFG.CNTMD   = (type == TYPE_BULK);
	USB.PIPECFG.SHTNAK  = 1;
	USB.PIPECFG.DIR     = dir_transmitting;
	USB.PIPECFG.EPNUM   = (address & 0x0f);

	USB.PIPEBUF.BUFSIZE = ep->bufsize - 1;
	USB.PIPEBUF.BUFNMB  = ep->bufnmb;

	USB.PIPEMAXP.MXPS   = le16toh(ep->dc->wMaxPacketSize);

	USB.PIPEPERI.IFIS = 0;
	USB.PIPEPERI.IITV = 0;

	if(ep->pipe >= 1 && ep->pipe <= 5) {
		USB.PIPETR[ep->pipe-1].TRE.TRCLR = 1;
		USB.PIPETR[ep->pipe-1].TRE.TRENB = 0;
	}
}

/* usb_pipe_clear(): Clear all data in the pipe */
void usb_pipe_clear(int pipe)
{
	if(pipe <= 0 || pipe > 9) return;

	/* Set PID=NAK then use ACLRM to clear the pipe */
	USB.PIPECTR[pipe-1].PID = PID_NAK;
	usb_while(USB.PIPECTR[pipe-1].PBUSY);

	USB.PIPECTR[pipe-1].ACLRM = 1;
	USB.PIPECTR[pipe-1].ACLRM = 0;

	/* Clear the sequence bit (important after a world switch since we
	   restore hardware registers but the connection to the hosts restarts
	   from scratch!) */
	USB.PIPECTR[pipe-1].SQCLR = 1;
	usb_while(USB.PIPECTR[pipe-1].SQMON != 0);
}

//---
// Operation on FIFO controllers
//---

/* fifoct_t: FIFO controllers to access pipe queues */
typedef enum {
	NOF = 0,  /* No FIFO controller */
	CF,       /* Used for the Default Control Pipe */
	D0F,      /* FIFO Controller 0 */
	D1F,      /* FIFO Controller 1 */
} GPACKEDENUM fifo_t;

enum {
	FIFO_READ   = 0, /* Read mode */
	FIFO_WRITE  = 1, /* Write mode */
};

/* fifo_find_available_controller(): Get a FIFO controller for a pipe */
static fifo_t fifo_find_available_controller(int pipe)
{
	if(pipe == 0) return CF;

	if(USB.D0FIFOSEL.CURPIPE == 0) return D0F;
	USB_LOG("D0 is unavailable!\n");
	if(USB.D1FIFOSEL.CURPIPE == 0) return D1F;
	USB_LOG("D1 is unavailable!\n");

	return NOF;
}

/* fifo_bind(): Bind a FIFO to a pipe in reading or writing mode */
static void fifo_bind(fifo_t ct, int pipe, int mode)
{
	int reading = (mode == FIFO_READ);
	int writing = (mode == FIFO_WRITE);

	/* RCNT=0 REW=0 MBW=2 BIGEND=1 ISEL=mode CURPIPE=0 */
	if(ct == CF) {
		USB.CFIFOSEL.word = 0x0900 | (mode << 5);
		usb_while(!USB.CFIFOCTR.FRDY || USB.CFIFOSEL.ISEL != mode);
	}
	/* RCNT=0 REW=0 DCLRM=reading DREQE=0 MBW=2 BIGEND=1 CURPIPE=pipe */
	if(ct == D0F) {
		USB.D0FIFOSEL.word = 0x0900 | (reading << 13) | pipe;
		usb_while(!USB.D0FIFOCTR.FRDY || USB.PIPECFG.DIR != mode);
	}
	if(ct == D1F) {
		USB.D1FIFOSEL.word = 0x0900 | (reading << 13) | pipe;
		usb_while(!USB.D1FIFOCTR.FRDY || USB.PIPECFG.DIR != mode);
	}

	/* Enable USB comunication! */
	if(pipe == 0 && writing)
		USB.DCPCTR.PID = PID_BUF;
	if(pipe != 0)
		USB.PIPECTR[pipe-1].PID = PID_BUF;
}

/* fifo_unbind(): Unbind a FIFO */
static void fifo_unbind(fifo_t ct)
{
	int pipe = -1;
	/* TODO: USB (DCP normalization): NAK when unbinding?
	if(ct == CF) {
		USB.DCPCTR.CCPL = 0;
		USB.DCPCTR.PID = PID_NAK;
		usb_while(!USB.DCPCTR.PBUSY);
	} */
	if(ct == D0F) pipe = USB.D0FIFOSEL.CURPIPE;
	if(ct == D1F) pipe = USB.D1FIFOSEL.CURPIPE;
	if(pipe <= 0)
		return;

	/* Disbable communication on the pipe */
	USB.PIPECTR[pipe-1].PID = PID_NAK;
	usb_while(USB.PIPECTR[pipe-1].PBUSY);

	if(ct == D0F) {
		USB.D0FIFOSEL.word = 0x0000;
		usb_while(USB.D0FIFOSEL.CURPIPE != 0);
	}
	if(ct == D1F) {
		USB.D1FIFOSEL.word = 0x0000;
		usb_while(USB.D1FIFOSEL.CURPIPE != 0);
	}
}

//---
// Writing operations
//---

/* The writing logic is asynchronous, which makes it sometimes hard to track.
   The series of call for a write I/O is zero or more usb_write_async()
   followed by a usb_commit_async():

     write_io ::= usb_write_async* usb_commit_async

   A usb_write_async() will write to the hardware buffer as many times as it
   takes to exhaust the input, including 1 time if the hardware buffer can hold
   the entire input and 0 times if there is no input. Each _round_ consists of
   a call to write_round() to copy with the CPU or start the copy with the DMA,
   and a call to finish_round() when the copy is finished.

   If the round fills the buffer, finish_round() is triggered by the BEMP
   interrupt after the hardware finishes transferring. Otherwise finish_round()
   is triggered directly when writing finishes.

     complete_round ::= write_round
                        <Finish writing with CPU or DMA>
                        <USB module auto-commits pipe>
                        <BEMP interrupt after transmission>
                        finish_round

     partial_round ::= write_round
                       <Finish writing with CPU or DMA>
                       finish_round

   Note that the "<Finish writing>" event is asynchronous if the DMA is used. A
   full write will take zero or more complete rounds followed by zero or one
   partial round before finish_call() is called:

     usb_write_async ::= complete_round* partial_round? finish_call

   And a commit will trigger a transmission of whatever is left in the buffer
   (including nothing) and wait for the BEMP interrupt.

     usb_commit_async ::= <Manually commit pipe>
                          <BEMP interrut after transmission>
                          finish_call

   Most functions can execute either in the main thread or within an interrupt
   handler. */
GBSS static asyncio_op_t pipe_transfers[10];

void usb_pipe_init_transfers(void)
{
	for(int i = 0; i < 10; i++)
		asyncio_op_clear(&pipe_transfers[i]);
}

void usb_wait_all_transfers(bool await_long_writes)
{
	while(1) {
		bool all_done = true;
		for(int i = 0; i < 10; i++) {
			asyncio_op_t const *t = &pipe_transfers[i];
			all_done &= !asyncio_op_busy(t);
			if(await_long_writes)
				all_done &= (t->type != ASYNCIO_WRITE);
		}
		if(all_done)
			return;
		sleep();
	}
}

/* Size of a pipe's buffer area, in bytes */
static int pipe_bufsize(int pipe)
{
	if(pipe == 0)
		return USB.DCPMAXP.MXPS;

	USB.PIPESEL.PIPESEL = pipe;
	return (USB.PIPEBUF.BUFSIZE + 1) * 64;
}

/* This function is called when a read/write/fsync call and its associated
   hardware interactions all complete. */
static void finish_call(asyncio_op_t *t, int pipe)
{
	/* Unbind the USB controller used for the call, except for writes since
	   the USB module requires us to keep it until the final commit */
	if(t->type != ASYNCIO_WRITE) {
		fifo_unbind(t->controller);
		t->controller = NOF;
	}

	/* Disable interrupts */
	if((t->type == ASYNCIO_WRITE || t->type == ASYNCIO_SYNC) && pipe != 0)
		USB.BEMPENB &= ~(1 << pipe);

	asyncio_op_finish_call(t);
	USB_TRACE("finish_call()");
}

/* This function is called when a round of writing has completed, including all
   hardware interactions. If the FIFO got filled by the writing, this is after
   the transmission and BEMP interrupt; otherwise this is when the CPU/DMA
   finished writing. */
static void finish_round(asyncio_op_t *t, int pipe)
{
//	USB_LOG("[PIPE%d] finish_round() for %d bytes\n", pipe, t->round_size);
	asyncio_op_finish_write_round(t);

	/* Account for auto-transfers */
	if(t->buffer_used == pipe_bufsize(pipe))
		t->buffer_used = 0;

	USB_TRACE("finish_round()");

	if(t->size == 0)
		finish_call(t, pipe);
}
/* write_round(): Write up to a FIFO's worth of data to a pipe

   If this is a partial round (FIFO not going to be full), finish_round() is
   invoked after the write. Otherwise the FIFO is transmitted automatically and
   the BEMP handler will call finish_round() after the transfer. */
static void write_round(asyncio_op_t *t, int pipe)
{
	fifo_t ct = t->controller;

	void volatile *FIFO = NULL;
	if(ct == CF)  FIFO = &USB.CFIFO;
	if(ct == D0F) FIFO = &USB.D0FIFO;
	if(ct == D1F) FIFO = &USB.D1FIFO;

	/* Amount of data that can be transferred in a single run */
	int available = pipe_bufsize(pipe) - t->buffer_used;
	int size = min(t->size, available);

	/* If this is a partial write (size < available), call finish_round()
	   after the copy to notify the user that the pipe is ready. Otherwise,
	   a USB transfer will occur and the BEMP handler will do it. */
	bool partial = (size < available);

	asyncio_op_start_write_round(t, size);

	if(t->dma)
	{
		gint_call_t callback = partial ?
			GINT_CALL(finish_round, (void *)t, pipe) :
			GINT_CALL_NULL;

		/* Use DMA channel 3 for D0F and 4 for D1F */
		int channel = (ct == D0F) ? 3 : 4;

		/* TODO: USB: Can we use 32-byte DMA transfers? */
		bool ok = dma_transfer_async(channel, DMA_4B, size >> 2,
			t->data_w, DMA_INC, (void *)FIFO, DMA_FIXED, callback);
		if(!ok) USB_LOG("DMA async failed on channel %d!\n", channel);
	}
	else
	{
		usb_pipe_write4(t->data_w, size, &t->shbuf, &t->shbuf_size,
			FIFO);
		if(partial) finish_round(t, pipe);
	}

	USB_TRACE("write_round()");
}

int usb_write_async(int pipe, void const *data, int size, bool use_dma,
	gint_call_t callback)
{
	asyncio_op_t *t = &pipe_transfers[pipe];
	if(asyncio_op_busy(t))
		return USB_WRITE_BUSY;

	/* If this if the first write of a series, find a controller. */
	/* TODO: usb_write_async(): TOC/TOU race on controller being free */
	if(t->controller == NOF) {
		fifo_t ct = fifo_find_available_controller(pipe);
		if(ct == NOF)
			return USB_WRITE_NOFIFO;
		fifo_bind(ct, pipe, FIFO_WRITE);
		t->controller = ct;
	}

	asyncio_op_start_write(t, data, size, use_dma, &callback);

	/* Set up the Buffer Empty interrupt to refill the buffer when it gets
	   empty, and be notified when the transfer completes. */
	USB.BEMPENB |= (1 << pipe);

	write_round(t, pipe);
	return 0;
}

int usb_write_sync_timeout(int pipe, void const *data, int size, bool use_dma,
	timeout_t const *timeout)
{
	volatile int flag = 0;

	while(1)
	{
		int rc = usb_write_async(pipe, data, size, use_dma,
			GINT_CALL_SET(&flag));
		if(rc == 0)
			break;
		if(rc == USB_WRITE_NOFIFO)
			USB_LOG("USB_WRITE_NOFIFO\n");
		if(rc != USB_WRITE_BUSY)
			return rc;
		if(timeout_elapsed(timeout))
			return USB_WRITE_TIMEOUT;
		sleep();
	}

	while(!flag)
	{
		if(timeout_elapsed(timeout))
			return USB_WRITE_TIMEOUT;
		sleep();
	}
	return 0;
}

int usb_write_sync(int pipe, void const *data, int size, bool dma)
{
	return usb_write_sync_timeout(pipe, data, size, dma, NULL);
}

int usb_commit_async(int pipe, gint_call_t callback)
{
	asyncio_op_t *t = &pipe_transfers[pipe];
	if(asyncio_op_busy(t))
		return USB_COMMIT_BUSY;
	if(t->type != ASYNCIO_WRITE || t->controller == NOF)
		return USB_COMMIT_INACTIVE;

	/* Flush any remaining bytes in the short buffer. This cannot fill the
	   buffer and create an auto-transmission situation; instead the module
	   remains idle after this write. This is because we only use 32-bit
	   writes, therefore at worst the buffer is 4 bytes away from being
	   full, and will not be filled by an extra 0-3 bytes. */
	void volatile *FIFO = NULL;
	if(t->controller == CF)  FIFO = &USB.CFIFO;
	if(t->controller == D0F) FIFO = &USB.D0FIFO;
	if(t->controller == D1F) FIFO = &USB.D1FIFO;
	usb_pipe_flush4(t->shbuf, t->shbuf_size, FIFO);

	/* Switch from WRITE to SYNC type; this influences the BEMP handler and
	   the final finish_call() */
	asyncio_op_start_sync(t, &callback);

	/* TODO: Figure out why previous attempts to use BEMP to finish commit
	   TODO| calls on the DCP failed with a freeze */
	if(pipe == 0) {
		USB.CFIFOCTR.BVAL = 1;
		finish_call(t, pipe);
		return 0;
	}

	/* Set BVAL=1 and inform the BEMP handler of the commitment with the
	   SYNC type; the handler will invoke finish_call() */
	USB.BEMPENB |= (1 << pipe);
	if(t->controller == D0F) USB.D0FIFOCTR.BVAL = 1;
	if(t->controller == D1F) USB.D1FIFOCTR.BVAL = 1;
	USB_LOG("[PIPE%d] Committed transfer\n", pipe);

	return 0;
}

int usb_commit_sync_timeout(int pipe, timeout_t const *timeout)
{
	int volatile flag = 0;

	/* Wait until the pipe is free, then commit */
	while(1)
	{
		int rc = usb_commit_async(pipe, GINT_CALL_SET(&flag));
		if(rc == 0)
			break;
		if(rc != USB_COMMIT_BUSY)
			return rc;
		if(timeout_elapsed(timeout))
			return USB_COMMIT_TIMEOUT;
		sleep();
	}

	/* Wait until the commit completes */
	while(!flag)
	{
		if(timeout_elapsed(timeout))
			return USB_COMMIT_TIMEOUT;
		sleep();
	}
	return 0;
}

void usb_commit_sync(int pipe)
{
	usb_commit_sync_timeout(pipe, NULL);
}

/* usb_pipe_write_bemp(): Callback for the BEMP interrupt on a pipe */
void usb_pipe_write_bemp(int pipe)
{
	asyncio_op_t *t = &pipe_transfers[pipe];

	if(t->type == ASYNCIO_SYNC)
	{
		finish_call(t, pipe);
	}
	else
	{
		/* Finish a round; if there is more data, keep going */
		finish_round(t, pipe);
		if(t->data_w) write_round(t, pipe);
	}
}