/*
 * Bt8xx based DVB adapter driver 
 *
 * Copyright (C) 2002,2003 Florian Schirmer <schirmer@taytron.net>
 * Copyright (C) 2002 Peter Hettkamp <peter.hettkamp@t-online.de>
 * Copyright (C) 1999-2001 Ralph  Metzler & Marcus Metzler for convergence integrated media GmbH
 * Copyright (C) 1998,1999 Christian Theiss <mistert@rz.fh-augsburg.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 <asm/bitops.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/i2c.h>

#include "dmxdev.h"
#include "dvbdev.h"
#include "dvb_demux.h"
#include "dvb_frontend.h"

#include "dvb-bt8xx.h"
#include "bt878.h"

#define dprintk if (debug) printk

extern int bttv_get_cardinfo(unsigned int card, int *type, int *cardid);
extern struct i2c_adapter *bttv_get_i2c_adap(unsigned int card);

static LIST_HEAD(card_list);
static int debug = 0;

#define TS_SIZE 188

static void dvb_bt8xx_task(unsigned long data)
{

   struct bt878 *bt = &bt878[0];
   struct dvb_bt8xx_card *card = (struct dvb_bt8xx_card *)data;
   int rb;
   u8 *rp1=0, *rp2=0;
   int count=0, count2=0, tp=0;
   int i, ii;
   int sync;
   u8 tsbuf[TS_SIZE]; /* a buffer to make a single TS packet crossing the wraparound */
                      /* point of the circular buffer contiguous in memory again */
					  
	if (!card->active)
		return;
   
   dprintk("pctv debug: tasklet called, data=0x%8.8lx\n",data);
//   bt=dvb->bt;

//   if(!dvb->feeding) return;
   
   spin_lock_irq(&bt->s_lock);

   /* the dma overtook us, or we overtook the dma? */
   if(bt->readbuf==bt->writebuf||
      bt->readbuf==(bt->writebuf+1)%bt->nbuffers) {
      spin_unlock_irq(&bt->s_lock);
      dprintk("pctv debug: tasklet: no do r=%d, w=%d\n",bt->readbuf, bt->writebuf);
      return;
   }

   /* are we frame synced? */
   if(((unsigned char *)bt->buffer)[bt->readbuf*bt->framesize+bt->readptr]!=0x47) {
      dprintk("pctv debug: tasklet: searching for sync\n");
      sync=TS_SIZE*2;
      do {
         if(sync--<=0) break;
         if(++bt->readptr>=bt->framesize) {
            bt->readptr=0;
            if(++bt->readbuf>=bt->nbuffers) bt->readbuf=0;
            if(bt->readbuf==bt->writebuf||
               bt->readbuf==(bt->writebuf+1)%bt->nbuffers) {
               spin_unlock_irq(&bt->s_lock);
               printk("pctv debug: tasklet: dma overtook us. r=%d, w=%d\n",bt->readbuf,bt->writebuf); 
               return;
            }
         }
         if(((u8 *)bt->buffer)[bt->readbuf*bt->framesize+bt->readptr]!=0x47) continue;
         /* ok, we have found a 0x47. See whether at TS_SIZE there is another 0x47 */
         if(bt->readptr+TS_SIZE<bt->framesize&&((u8 *)bt->buffer)[bt->readbuf*bt->framesize+bt->readptr+TS_SIZE]==0x47) {
            sync=0;
            break;
         }
         if(bt->readptr+TS_SIZE>=bt->framesize) {
	    /* the payload area of a TS packet may contain a 0x47. To be sure we
	       are not looking at such a 0x47, check if there is another one exactly
	       TS_SIZE further. But if this crosses a frame boundary, check if the
	       frame is free to access, and handle buffer wraparound. I did not yet
	       have the patience to do this :-(
	    */ 
            printk("pctv: panic, less than 188 Bytes left and no sync. Program me!\n");
            bt->readptr++;
            spin_unlock_irq(&bt->s_lock);
            return;
         }
      } while(sync);
      dprintk("pctv tasklet: end of sync search @%d[%x]=%x\n",
              bt->readbuf,bt->readptr,
              ((u8 *)bt->buffer)[bt->readbuf*bt->framesize+bt->readptr]);
   }

   /* now find out how many TS frames are available in the buffer */
   rp1=(u8 *)bt->buffer+(bt->readbuf*bt->framesize+bt->readptr);
   if(*rp1!=0x47) {
      spin_unlock_irq(&bt->s_lock); 
      return;
   }
   
   count=bt->writebuf-bt->readbuf;
   if(count<0) {
      count=bt->nbuffers-bt->readbuf;
      count2=bt->writebuf;
   }
   count=count*bt->framesize-bt->readptr;
   count/=TS_SIZE;
   if(count2) {
      rb=bt->readbuf*bt->framesize+bt->readptr+count*TS_SIZE;
      while(rb<bt->buffersize&&tp<TS_SIZE) {
      tsbuf[tp++]=((u8 *)bt->buffer)[rb++];
      }
      rb=0;
      while(tp<TS_SIZE) {
         tsbuf[tp++]=((u8 *)bt->buffer)[rb++];
      }
      count2=count2*bt->framesize-rb;
      count2/=TS_SIZE;
      rp2=(u8 *)bt->buffer+rb;
   }

   i=bt->readbuf*bt->framesize+bt->readptr+TS_SIZE*(count+count2+(tp!=0));
   dprintk("pctv debug: tasklet: i=%d (%d ts frames)\n",i,(i-bt->readbuf*bt->framesize-bt->readptr)/TS_SIZE);
   if(i>=bt->buffersize) i-=bt->buffersize;
      
   /* update the bt878 read pointers, release the lock */
   ii=bt->readbuf;
   bt->readbuf=(i/bt->framesize);
   if(bt->readbuf>=bt->nbuffers) {
      /* this should not happen any more */
      printk("pctv tasklet: i miscomputed bt->readbuf=0x%x>nbuffers=0x%x\n",
             bt->readbuf,bt->nbuffers);
      printk("pctv tasklet: readbuf %x frsize %x readptr %x count %x count2 %x\n",ii,bt->framesize,bt->readptr,count,count2);
      printk("pctv tasklet: TS_SZ %x span %x i %x res readbuf %x\n",TS_SIZE,(tp!=0),i,bt->readbuf);
      bt->readbuf-=bt->nbuffers;
   }
   bt->readptr=(i%bt->framesize);
   if(bt->readptr>=bt->framesize) {
      /* this should not happen at all... */
      printk("pctv tasklet: i miscomputed bt->readptr=0x%x>framesize=0x%x\n",
             bt->readptr,bt->framesize);
      bt->readptr-=bt->framesize;
   }

   spin_unlock_irq(&bt->s_lock);
   
   dprintk("pctv tasklet: count1=%d, count2=%d, %sr=%d[%x]\n",count,count2,tp?"span, ":"",bt->readbuf,bt->readptr);

   /* send the first (or only) part of the buffer */
   if(count>0&&count<bt->buffersize/TS_SIZE&&*rp1==0x47)
      dvb_dmx_swfilter_packets(&card->demux,rp2,count2);
   else {
      if(count>0)dprintk("pctv debug: tasklet: error calling demux, c=%d, *buf=0x%x\n",count,*rp1);
   }
   
   /* if the buffer crosses the buffer-wrap, copy the one TS into a local buffer,
      then send it. Copy has been done above. */
   if(tp&&tsbuf[0]==0x47) {
      dvb_dmx_swfilter_packets(&card->demux,rp2,count2);
      tp=0;
   } else {
      if(tp)dprintk("pctv debug: tasklet: error calling demux1, tsbuf[0]=0x%x\n",tsbuf[0]);
   }
   
   /* send the third and last part of the buffer */   
   if(count2>0&&count2<bt->buffersize/TS_SIZE&&*rp2==0x47)
      dvb_dmx_swfilter_packets(&card->demux,rp2,count2);
   else {
      if(count2>0)dprintk("pctv debug: tasklet: error calling demux2, c=%d, *buf=0x%x\n",count2,*rp2);
   }

}

static DECLARE_TASKLET_DISABLED(dvb_bt8xx_tasklet, dvb_bt8xx_task, 0);

static int dvb_bt8xx_master_xfer(struct dvb_i2c_bus *i2c, const struct i2c_msg msgs[], int num)
{

	struct dvb_bt8xx_card *card = (struct dvb_bt8xx_card *)i2c->data;

	return card->i2c_adap->algo->master_xfer(card->i2c_adap, (struct i2c_msg *)msgs, num);

}

static int dvb_bt8xx_start_feed(struct dvb_demux_feed *dvbdmxfeed)
{

	struct dvb_demux *dvbdmx = dvbdmxfeed->demux;
	struct dvb_bt8xx_card *card = dvbdmx->priv;

	printk("dvb_bt8xx: start_feed\n");
	
	if (!dvbdmx->dmx.frontend)
		return -EINVAL;

	if (card->active)
		return 0;
		
	card->active = 1;
	
	bt878_start(&bt878[0], (0 << 26) | (0 << 15) | (1 << 14) | (0 << 6) | (1 << 5));

	return 0;

}

static int dvb_bt8xx_stop_feed(struct dvb_demux_feed *dvbdmxfeed)
{

	struct dvb_demux *dvbdmx = dvbdmxfeed->demux;
	struct dvb_bt8xx_card *card = dvbdmx->priv;

	printk("dvb_bt8xx: stop_feed\n");
	
	if (!dvbdmx->dmx.frontend)
		return -EINVAL;
		
	if (!card->active)
		return 0;

	bt878_stop(&bt878[0]);
	card->active = 0;

	return 0;

}

static int __init dvb_bt8xx_load(unsigned int bttv_nr)
{

	struct dvb_bt8xx_card *card;
	int result;
	
	if (!(card = kmalloc(sizeof(struct dvb_bt8xx_card), GFP_KERNEL)))
		return -ENOMEM;
		
	card->bttv_nr = bttv_nr;
	
	if (!(card->i2c_adap = bttv_get_i2c_adap(card->bttv_nr))) {

		printk("dvb_bt8xx: unable to determine i2c adapter of card%d\n", card->bttv_nr);

		kfree(card);
		
		return -EFAULT;
	
	}

	if ((result = dvb_register_adapter(&card->adapter, "Bt8xx based DVB adapter")) < 0) {
	
		printk("dvb_bt8xx: dvb_register_adapter failed (errno = %d)\n", result);
		
		kfree(card);
		
		return result;
		
	}

	if (!(dvb_register_i2c_bus(dvb_bt8xx_master_xfer, card, card->adapter, 0))) {

		printk("dvb_bt8xx: dvb_register_i2c_bus of card%d failed\n", card->bttv_nr);

		dvb_unregister_adapter(card->adapter);

		kfree(card);

		return -EFAULT;

	}

	memset(&card->demux, 0, sizeof(struct dvb_demux));

	card->demux.dmx.vendor = "Connexant";
	card->demux.dmx.model = "Software";
	card->demux.dmx.id = "demux0_0";
	card->demux.dmx.capabilities = DMX_TS_FILTERING | DMX_SECTION_FILTERING | DMX_MEMORY_BASED_FILTERING;

	card->demux.priv = card;
	card->demux.filternum = 256;
	card->demux.feednum = 256;
	card->demux.start_feed = dvb_bt8xx_start_feed;
	card->demux.stop_feed = dvb_bt8xx_stop_feed;
	card->demux.write_to_decoder = NULL;
	
	if ((result = dvb_dmx_init(&card->demux)) < 0) {
	
		printk("dvb_bt8xx: dvb_dmx_init failed (errno = %d)\n", result);

		dvb_unregister_i2c_bus(dvb_bt8xx_master_xfer, card->adapter, 0);
		dvb_unregister_adapter(card->adapter);
		
		return result;
		
	}

	card->dmxdev.filternum = 256;
	card->dmxdev.demux = &card->demux.dmx;
	card->dmxdev.capabilities = 0;
	
	if ((result = dvb_dmxdev_init(&card->dmxdev, card->adapter)) < 0) {
	
		printk("dvb_bt8xx: dvb_dmxdev_init failed (errno = %d)\n", result);

		dvb_dmx_release(&card->demux);
		dvb_unregister_i2c_bus(dvb_bt8xx_master_xfer, card->adapter, 0);
		dvb_unregister_adapter(card->adapter);
		
		return result;
	
	}

	card->fe_hw.id = "hw_frontend";
	card->fe_hw.vendor = "Connexant";
	card->fe_hw.model = "hw";
	card->fe_hw.source = DMX_FRONTEND_0;

	if ((result = card->demux.dmx.add_frontend(&card->demux.dmx, &card->fe_hw)) < 0) {
	
		printk("dvb_bt8xx: dvb_dmx_init failed (errno = %d)\n", result);

		dvb_dmxdev_release(&card->dmxdev);
		dvb_dmx_release(&card->demux);
		dvb_unregister_i2c_bus(dvb_bt8xx_master_xfer, card->adapter, 0);
		dvb_unregister_adapter(card->adapter);
		
		return result;
		
	}
	
	card->fe_mem.id = "mem_frontend";
	card->fe_mem.vendor = "memory";
	card->fe_mem.model = "sw";
	card->fe_mem.source = DMX_MEMORY_FE;

	if ((result = card->demux.dmx.add_frontend(&card->demux.dmx, &card->fe_mem)) < 0) {
	
		printk("dvb_bt8xx: dvb_dmx_init failed (errno = %d)\n", result);

		card->demux.dmx.remove_frontend(&card->demux.dmx, &card->fe_hw);
		dvb_dmxdev_release(&card->dmxdev);
		dvb_dmx_release(&card->demux);
		dvb_unregister_i2c_bus(dvb_bt8xx_master_xfer, card->adapter, 0);
		dvb_unregister_adapter(card->adapter);
		
		return result;
		
	}

	if ((result = card->demux.dmx.connect_frontend(&card->demux.dmx, &card->fe_hw)) < 0) {
	
		printk("dvb_bt8xx: dvb_dmx_init failed (errno = %d)\n", result);

		card->demux.dmx.remove_frontend(&card->demux.dmx, &card->fe_mem);
		card->demux.dmx.remove_frontend(&card->demux.dmx, &card->fe_hw);
		dvb_dmxdev_release(&card->dmxdev);
		dvb_dmx_release(&card->demux);
		dvb_unregister_i2c_bus(dvb_bt8xx_master_xfer, card->adapter, 0);
		dvb_unregister_adapter(card->adapter);
		
		return result;
		
	}
	
	dvb_bt8xx_tasklet.data = (long)card;
	bt878[0].tasklet = &dvb_bt8xx_tasklet;
	
	bt878_get_buffers(&bt878[0], 0xC00, 8, 4, 0);

	list_add_tail(&card->list, &card_list);

	return 0;

}

static void dvb_bt8xx_close(void)
{

	struct dvb_bt8xx_card *card;
	struct list_head *entry, *entry_safe;

	list_for_each_safe(entry, entry_safe, &card_list) {

		card = list_entry(entry, struct dvb_bt8xx_card, list);
		
		dprintk("dvb_bt8xx: unloading card%d\n", card->bttv_nr);

		card->demux.dmx.remove_frontend(&card->demux.dmx, &card->fe_mem);
		card->demux.dmx.remove_frontend(&card->demux.dmx, &card->fe_hw);
		dvb_dmxdev_release(&card->dmxdev);
		dvb_dmx_release(&card->demux);
		dvb_unregister_i2c_bus(dvb_bt8xx_master_xfer, card->adapter, 0);
		dvb_unregister_adapter(card->adapter);
		
		kfree(card);
		
		list_del(&card->list);
		
	}

}

static int __init dvb_bt8xx_init(void)
{

	int result;
	int card_id;
	unsigned int card_nr;
	int card_type;

	dprintk("dvb_bt8xx: enumerating availible bttv cards...\n");
	
	for (card_nr = 0; !bttv_get_cardinfo(card_nr, &card_type, &card_id); card_nr++) {
	
		if (card_id == 0x01010071) {
		
			dprintk("dvb_bt8xx: identified card%d as Nebula DigiTV DVB-T card\n", card_nr);
			
			if ((result = dvb_bt8xx_load(card_nr)) < 0) {
			
				dvb_bt8xx_close();
				
				return result;
				
			}
		
		}
		
	}

	return 0;

}

static void __exit dvb_bt8xx_exit(void)
{

	dvb_bt8xx_close();

}

module_init(dvb_bt8xx_init);
module_exit(dvb_bt8xx_exit);
MODULE_DESCRIPTION("Bt8xx based DVB adapter driver");
MODULE_AUTHOR("Florian Schirmer <schirmer@taytron.net>");
MODULE_LICENSE("GPL");
MODULE_PARM(debug, "i");