/*
 * Copyright (C) 2007, 2008 Karsten Wiese <fzu@wemgehoertderstaat.de>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 *
 * This program 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 General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/usb.h>
#include <linux/gfp.h>

#include "usb_stream.h"


/*                             setup                                  */

static unsigned usb_stream_next_packet_size(struct usb_stream_kernel *sk)
{
	struct usb_stream *s = sk->s;
	sk->out_phase_peeked = (sk->out_phase & 0xffff) + sk->freqn;
	return (sk->out_phase_peeked >> 16) * s->cfg.frame_size;
}

static void playback_prep_freqn(struct usb_stream_kernel *sk, struct urb *urb)
{
	struct usb_stream *s = sk->s;
	int pack, lb = 0;

	for (pack = 0; pack < sk->n_o_ps; pack++) {
		int l = usb_stream_next_packet_size(sk);
		if (s->idle_outsize + lb + l > s->period_size)
			goto check;

		sk->out_phase = sk->out_phase_peeked;
		urb->iso_frame_desc[pack].offset = lb;
		urb->iso_frame_desc[pack].length = l;
		lb += l;
	}
	snd_printdd(KERN_DEBUG "%i\n", lb);

check:
	urb->number_of_packets = pack;
	urb->transfer_buffer_length = lb;
	s->idle_outsize += lb - s->period_size;
	snd_printdd(KERN_DEBUG "idle=%i ul=%i ps=%i\n", s->idle_outsize,
		    lb, s->period_size);
}

static void init_pipe_urbs(struct usb_stream_kernel *sk, unsigned use_packsize,
			   struct urb **urbs, char *transfer,
			   struct usb_device *dev, int pipe)
{
	int u, p;
	int maxpacket = use_packsize ?
		use_packsize : usb_maxpacket(dev, pipe, usb_pipeout(pipe));
	int transfer_length = maxpacket * sk->n_o_ps;

	for (u = 0; u < USB_STREAM_NURBS;
	     ++u, transfer += transfer_length) {
		struct urb *urb = urbs[u];
		struct usb_iso_packet_descriptor *desc;
		urb->transfer_buffer = transfer;
		urb->dev = dev;
		urb->pipe = pipe;
		urb->number_of_packets = sk->n_o_ps;
		urb->context = sk;
		urb->interval = 1;
		if (usb_pipeout(pipe))
			continue;

		urb->transfer_buffer_length = transfer_length;
		desc = urb->iso_frame_desc;
		desc->offset = 0;
		desc->length = maxpacket;
		for (p = 1; p < sk->n_o_ps; ++p) {
			desc[p].offset = desc[p - 1].offset + maxpacket;
			desc[p].length = maxpacket;
		}
	}
}

static void init_urbs(struct usb_stream_kernel *sk, unsigned use_packsize,
		      struct usb_device *dev, int in_pipe, int out_pipe)
{
	struct usb_stream	*s = sk->s;
	char			*indata = (char *)s + sizeof(*s) +
					sizeof(struct usb_stream_packet) *
					s->inpackets;
	int			u;

	for (u = 0; u < USB_STREAM_NURBS; ++u) {
		sk->inurb[u] = usb_alloc_urb(sk->n_o_ps, GFP_KERNEL);
		sk->outurb[u] = usb_alloc_urb(sk->n_o_ps, GFP_KERNEL);
	}

	init_pipe_urbs(sk, use_packsize, sk->inurb, indata, dev, in_pipe);
	init_pipe_urbs(sk, use_packsize, sk->outurb, sk->write_page, dev,
		       out_pipe);
}


/*
 * convert a sampling rate into our full speed format (fs/1000 in Q16.16)
 * this will overflow at approx 524 kHz
 */
static inline unsigned get_usb_full_speed_rate(unsigned rate)
{
	return ((rate << 13) + 62) / 125;
}

/*
 * convert a sampling rate into USB high speed format (fs/8000 in Q16.16)
 * this will overflow at approx 4 MHz
 */
static inline unsigned get_usb_high_speed_rate(unsigned rate)
{
	return ((rate << 10) + 62) / 125;
}

void usb_stream_free(struct usb_stream_kernel *sk)
{
	struct usb_stream *s;
	unsigned u;

	for (u = 0; u < USB_STREAM_NURBS; ++u) {
		usb_free_urb(sk->inurb[u]);
		sk->inurb[u] = NULL;
		usb_free_urb(sk->outurb[u]);
		sk->outurb[u] = NULL;
	}

	s = sk->s;
	if (!s)
		return;

	free_pages((unsigned long)sk->write_page, get_order(s->write_size));
	sk->write_page = NULL;
	free_pages((unsigned long)s, get_order(s->read_size));
	sk->s = NULL;
}

struct usb_stream *usb_stream_new(struct usb_stream_kernel *sk,
				  struct usb_device *dev,
				  unsigned in_endpoint, unsigned out_endpoint,
				  unsigned sample_rate, unsigned use_packsize,
				  unsigned period_frames, unsigned frame_size)
{
	int packets, max_packsize;
	int in_pipe, out_pipe;
	int read_size = sizeof(struct usb_stream);
	int write_size;
	int usb_frames = dev->speed == USB_SPEED_HIGH ? 8000 : 1000;
	int pg;

	in_pipe = usb_rcvisocpipe(dev, in_endpoint);
	out_pipe = usb_sndisocpipe(dev, out_endpoint);

	max_packsize = use_packsize ?
		use_packsize : usb_maxpacket(dev, in_pipe, 0);

	/*
		t_period = period_frames / sample_rate
		iso_packs = t_period / t_iso_frame
			= (period_frames / sample_rate) * (1 / t_iso_frame)
	*/

	packets = period_frames * usb_frames / sample_rate + 1;

	if (dev->speed == USB_SPEED_HIGH)
		packets = (packets + 7) & ~7;

	read_size += packets * USB_STREAM_URBDEPTH *
		(max_packsize + sizeof(struct usb_stream_packet));

	max_packsize = usb_maxpacket(dev, out_pipe, 1);
	write_size = max_packsize * packets * USB_STREAM_URBDEPTH;

	if (read_size >= 256*PAGE_SIZE || write_size >= 256*PAGE_SIZE) {
		snd_printk(KERN_WARNING "a size exceeds 128*PAGE_SIZE\n");
		goto out;
	}

	pg = get_order(read_size);
	sk->s = (void *) __get_free_pages(GFP_KERNEL|__GFP_COMP|__GFP_ZERO, pg);
	if (!sk->s) {
		snd_printk(KERN_WARNING "couldn't __get_free_pages()\n");
		goto out;
	}
	sk->s->cfg.version = USB_STREAM_INTERFACE_VERSION;

	sk->s->read_size = read_size;

	sk->s->cfg.sample_rate = sample_rate;
	sk->s->cfg.frame_size = frame_size;
	sk->n_o_ps = packets;
	sk->s->inpackets = packets * USB_STREAM_URBDEPTH;
	sk->s->cfg.period_frames = period_frames;
	sk->s->period_size = frame_size * period_frames;

	sk->s->write_size = write_size;
	pg = get_order(write_size);

	sk->write_page =
		(void *)__get_free_pages(GFP_KERNEL|__GFP_COMP|__GFP_ZERO, pg);
	if (!sk->write_page) {
		snd_printk(KERN_WARNING "couldn't __get_free_pages()\n");
		usb_stream_free(sk);
		return NULL;
	}

	/* calculate the frequency in 16.16 format */
	if (dev->speed == USB_SPEED_FULL)
		sk->freqn = get_usb_full_speed_rate(sample_rate);
	else
		sk->freqn = get_usb_high_speed_rate(sample_rate);

	init_urbs(sk, use_packsize, dev, in_pipe, out_pipe);
	sk->s->state = usb_stream_stopped;
out:
	return sk->s;
}


/*                             start                                  */

static bool balance_check(struct usb_stream_kernel *sk, struct urb *urb)
{
	bool r;
	if (unlikely(urb->status)) {
		if (urb->status != -ESHUTDOWN && urb->status != -ENOENT)
			snd_printk(KERN_WARNING "status=%i\n", urb->status);
		sk->iso_frame_balance = 0x7FFFFFFF;
		return false;
	}
	r = sk->iso_frame_balance == 0;
	if (!r)
		sk->i_urb = urb;
	return r;
}

static bool balance_playback(struct usb_stream_kernel *sk, struct urb *urb)
{
	sk->iso_frame_balance += urb->number_of_packets;
	return balance_check(sk, urb);
}

static bool balance_capture(struct usb_stream_kernel *sk, struct urb *urb)
{
	sk->iso_frame_balance -= urb->number_of_packets;
	return balance_check(sk, urb);
}

static void subs_set_complete(struct urb **urbs, void (*complete)(struct urb *))
{
	int u;

	for (u = 0; u < USB_STREAM_NURBS; u++) {
		struct urb *urb = urbs[u];
		urb->complete = complete;
	}
}

static int usb_stream_prepare_playback(struct usb_stream_kernel *sk,
		struct urb *inurb)
{
	struct usb_stream *s = sk->s;
	struct urb *io;
	struct usb_iso_packet_descriptor *id, *od;
	int p = 0, lb = 0, l = 0;

	io = sk->idle_outurb;
	od = io->iso_frame_desc;

	for (; s->sync_packet < 0; ++p, ++s->sync_packet) {
		struct urb *ii = sk->completed_inurb;
		id = ii->iso_frame_desc +
			ii->number_of_packets + s->sync_packet;
		l = id->actual_length;

		od[p].length = l;
		od[p].offset = lb;
		lb += l;
	}

	for (;
	     s->sync_packet < inurb->number_of_packets && p < sk->n_o_ps;
	     ++p, ++s->sync_packet) {
		l = inurb->iso_frame_desc[s->sync_packet].actual_length;

		if (s->idle_outsize + lb + l > s->period_size)
			goto check_ok;

		od[p].length = l;
		od[p].offset = lb;
		lb += l;
	}

check_ok:
	s->sync_packet -= inurb->number_of_packets;
	if (unlikely(s->sync_packet < -2 || s->sync_packet > 0)) {
		snd_printk(KERN_WARNING "invalid sync_packet = %i;"
			   " p=%i nop=%i %i %x %x %x > %x\n",
			   s->sync_packet, p, inurb->number_of_packets,
			   s->idle_outsize + lb + l,
			   s->idle_outsize, lb,  l,
			   s->period_size);
		return -1;
	}
	if (unlikely(lb % s->cfg.frame_size)) {
		snd_printk(KERN_WARNING"invalid outsize = %i\n",
			   lb);
		return -1;
	}
	s->idle_outsize += lb - s->period_size;
	io->number_of_packets = p;
	io->transfer_buffer_length = lb;
	if (s->idle_outsize <= 0)
		return 0;

	snd_printk(KERN_WARNING "idle=%i\n", s->idle_outsize);
	return -1;
}

static void prepare_inurb(int number_of_packets, struct urb *iu)
{
	struct usb_iso_packet_descriptor *id;
	int p;

	iu->number_of_packets = number_of_packets;
	id = iu->iso_frame_desc;
	id->offset = 0;
	for (p = 0; p < iu->number_of_packets - 1; ++p)
		id[p + 1].offset = id[p].offset + id[p].length;

	iu->transfer_buffer_length =
		id[0].length * iu->number_of_packets;
}

static int submit_urbs(struct usb_stream_kernel *sk,
		       struct urb *inurb, struct urb *outurb)
{
	int err;
	prepare_inurb(sk->idle_outurb->number_of_packets, sk->idle_inurb);
	err = usb_submit_urb(sk->idle_inurb, GFP_ATOMIC);
	if (err < 0) {
		snd_printk(KERN_ERR "%i\n", err);
		return err;
	}
	sk->idle_inurb = sk->completed_inurb;
	sk->completed_inurb = inurb;
	err = usb_submit_urb(sk->idle_outurb, GFP_ATOMIC);
	if (err < 0) {
		snd_printk(KERN_ERR "%i\n", err);
		return err;
	}
	sk->idle_outurb = sk->completed_outurb;
	sk->completed_outurb = outurb;
	return 0;
}

#ifdef DEBUG_LOOP_BACK
/*
  This loop_back() shows how to read/write the period data.
 */
static void loop_back(struct usb_stream *s)
{
	char *i, *o;
	int il, ol, l, p;
	struct urb *iu;
	struct usb_iso_packet_descriptor *id;

	o = s->playback1st_to;
	ol = s->playback1st_size;
	l = 0;

	if (s->insplit_pack >= 0) {
		iu = sk->idle_inurb;
		id = iu->iso_frame_desc;
		p = s->insplit_pack;
	} else
		goto second;
loop:
	for (; p < iu->number_of_packets && l < s->period_size; ++p) {
		i = iu->transfer_buffer + id[p].offset;
		il = id[p].actual_length;
		if (l + il > s->period_size)
			il = s->period_size - l;
		if (il <= ol) {
			memcpy(o, i, il);
			o += il;
			ol -= il;
		} else {
			memcpy(o, i, ol);
			singen_6pack(o, ol);
			o = s->playback_to;
			memcpy(o, i + ol, il - ol);
			o += il - ol;
			ol = s->period_size - s->playback1st_size;
		}
		l += il;
	}
	if (iu == sk->completed_inurb) {
		if (l != s->period_size)
			printk(KERN_DEBUG"%s:%i %i\n", __func__, __LINE__,
			       l/(int)s->cfg.frame_size);

		return;
	}
second:
	iu = sk->completed_inurb;
	id = iu->iso_frame_desc;
	p = 0;
	goto loop;

}
#else
static void loop_back(struct usb_stream *s)
{
}
#endif

static void stream_idle(struct usb_stream_kernel *sk,
			struct urb *inurb, struct urb *outurb)
{
	struct usb_stream *s = sk->s;
	int l, p;
	int insize = s->idle_insize;
	int urb_size = 0;

	s->inpacket_split = s->next_inpacket_split;
	s->inpacket_split_at = s->next_inpacket_split_at;
	s->next_in<style>
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