linux-stable/drivers/media/video/videobuf-dvb.c
Darron Broad 59b1842da1 V4L/DVB (9227): MFE: Add multi-frontend mutual exclusion
This add frontend R/W mutual exclusion.
Prior to this point in time it was possible to open both
frontends simultaneously which an MFE card cannot support.

In order to stop this, a delayed open is performed which
has the following function:

-  Return EBUSY after a configurable amount of time
   if a frontend is unavailable due to the other being
   in use.

-  Only allow opening of a frontend if the kernel thread
   of the other has stopped.

This solution was chosen to allow switching between
frontends to work as seamlessly as possible. When both
frontends are actually opened simultaneously then one
will only open, but if quick switching is performed
between one of many then the new open will succeed in
a clean fashion rather than interrupting a kernel
thread.

Signed-off-by: Darron Broad <darron@kewl.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2008-10-17 17:24:15 -03:00

385 lines
9.7 KiB
C

/*
*
* some helper function for simple DVB cards which simply DMA the
* complete transport stream and let the computer sort everything else
* (i.e. we are using the software demux, ...). Also uses the
* video-buf to manage DMA buffers.
*
* (c) 2004 Gerd Knorr <kraxel@bytesex.org> [SUSE Labs]
*
* 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.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/kthread.h>
#include <linux/file.h>
#include <linux/freezer.h>
#include <media/videobuf-core.h>
#include <media/videobuf-dvb.h>
/* ------------------------------------------------------------------ */
MODULE_AUTHOR("Gerd Knorr <kraxel@bytesex.org> [SuSE Labs]");
MODULE_LICENSE("GPL");
static unsigned int debug;
module_param(debug, int, 0644);
MODULE_PARM_DESC(debug,"enable debug messages");
#define dprintk(fmt, arg...) if (debug) \
printk(KERN_DEBUG "%s/dvb: " fmt, dvb->name , ## arg)
/* ------------------------------------------------------------------ */
static int videobuf_dvb_thread(void *data)
{
struct videobuf_dvb *dvb = data;
struct videobuf_buffer *buf;
unsigned long flags;
int err;
void *outp;
dprintk("dvb thread started\n");
set_freezable();
videobuf_read_start(&dvb->dvbq);
for (;;) {
/* fetch next buffer */
buf = list_entry(dvb->dvbq.stream.next,
struct videobuf_buffer, stream);
list_del(&buf->stream);
err = videobuf_waiton(buf,0,1);
/* no more feeds left or stop_feed() asked us to quit */
if (0 == dvb->nfeeds)
break;
if (kthread_should_stop())
break;
try_to_freeze();
/* feed buffer data to demux */
outp = videobuf_queue_to_vmalloc (&dvb->dvbq, buf);
if (buf->state == VIDEOBUF_DONE)
dvb_dmx_swfilter(&dvb->demux, outp,
buf->size);
/* requeue buffer */
list_add_tail(&buf->stream,&dvb->dvbq.stream);
spin_lock_irqsave(dvb->dvbq.irqlock,flags);
dvb->dvbq.ops->buf_queue(&dvb->dvbq,buf);
spin_unlock_irqrestore(dvb->dvbq.irqlock,flags);
}
videobuf_read_stop(&dvb->dvbq);
dprintk("dvb thread stopped\n");
/* Hmm, linux becomes *very* unhappy without this ... */
while (!kthread_should_stop()) {
set_current_state(TASK_INTERRUPTIBLE);
schedule();
}
return 0;
}
static int videobuf_dvb_start_feed(struct dvb_demux_feed *feed)
{
struct dvb_demux *demux = feed->demux;
struct videobuf_dvb *dvb = demux->priv;
int rc;
if (!demux->dmx.frontend)
return -EINVAL;
mutex_lock(&dvb->lock);
dvb->nfeeds++;
rc = dvb->nfeeds;
if (NULL != dvb->thread)
goto out;
dvb->thread = kthread_run(videobuf_dvb_thread,
dvb, "%s dvb", dvb->name);
if (IS_ERR(dvb->thread)) {
rc = PTR_ERR(dvb->thread);
dvb->thread = NULL;
}
out:
mutex_unlock(&dvb->lock);
return rc;
}
static int videobuf_dvb_stop_feed(struct dvb_demux_feed *feed)
{
struct dvb_demux *demux = feed->demux;
struct videobuf_dvb *dvb = demux->priv;
int err = 0;
mutex_lock(&dvb->lock);
dvb->nfeeds--;
if (0 == dvb->nfeeds && NULL != dvb->thread) {
// FIXME: cx8802_cancel_buffers(dev);
err = kthread_stop(dvb->thread);
dvb->thread = NULL;
}
mutex_unlock(&dvb->lock);
return err;
}
/* ------------------------------------------------------------------ */
/* Register a single adapter and one or more frontends */
int videobuf_dvb_register_bus(struct videobuf_dvb_frontends *f,
struct module *module,
void *adapter_priv,
struct device *device,
short *adapter_nr,
int mfe_shared)
{
struct list_head *list, *q;
struct videobuf_dvb_frontend *fe;
int res = -EINVAL;
fe = videobuf_dvb_get_frontend(f, 1);
if (!fe) {
printk(KERN_WARNING "Unable to register the adapter which has no frontends\n");
goto err;
}
/* Bring up the adapter */
res = videobuf_dvb_register_adapter(f, module, adapter_priv, device, fe->dvb.name, adapter_nr, mfe_shared);
if (res < 0) {
printk(KERN_WARNING "videobuf_dvb_register_adapter failed (errno = %d)\n", res);
goto err;
}
/* Attach all of the frontends to the adapter */
mutex_lock(&f->lock);
list_for_each_safe(list, q, &f->frontend.felist) {
fe = list_entry(list, struct videobuf_dvb_frontend, felist);
res = videobuf_dvb_register_frontend(&f->adapter, &fe->dvb);
if (res < 0) {
printk(KERN_WARNING "%s: videobuf_dvb_register_frontend failed (errno = %d)\n",
fe->dvb.name, res);
}
}
mutex_unlock(&f->lock);
err:
return res;
}
int videobuf_dvb_register_adapter(struct videobuf_dvb_frontends *fe,
struct module *module,
void *adapter_priv,
struct device *device,
char *adapter_name,
short *adapter_nr,
int mfe_shared)
{
int result;
mutex_init(&fe->lock);
/* register adapter */
result = dvb_register_adapter(&fe->adapter, adapter_name, module, device, adapter_nr);
if (result < 0) {
printk(KERN_WARNING "%s: dvb_register_adapter failed (errno = %d)\n",
adapter_name, result);
}
fe->adapter.priv = adapter_priv;
fe->adapter.mfe_shared = mfe_shared;
return result;
}
int videobuf_dvb_register_frontend(struct dvb_adapter *adapter, struct videobuf_dvb *dvb)
{
int result;
/* register frontend */
result = dvb_register_frontend(adapter, dvb->frontend);
if (result < 0) {
printk(KERN_WARNING "%s: dvb_register_frontend failed (errno = %d)\n",
dvb->name, result);
goto fail_frontend;
}
/* register demux stuff */
dvb->demux.dmx.capabilities =
DMX_TS_FILTERING | DMX_SECTION_FILTERING |
DMX_MEMORY_BASED_FILTERING;
dvb->demux.priv = dvb;
dvb->demux.filternum = 256;
dvb->demux.feednum = 256;
dvb->demux.start_feed = videobuf_dvb_start_feed;
dvb->demux.stop_feed = videobuf_dvb_stop_feed;
result = dvb_dmx_init(&dvb->demux);
if (result < 0) {
printk(KERN_WARNING "%s: dvb_dmx_init failed (errno = %d)\n",
dvb->name, result);
goto fail_dmx;
}
dvb->dmxdev.filternum = 256;
dvb->dmxdev.demux = &dvb->demux.dmx;
dvb->dmxdev.capabilities = 0;
result = dvb_dmxdev_init(&dvb->dmxdev, adapter);
if (result < 0) {
printk(KERN_WARNING "%s: dvb_dmxdev_init failed (errno = %d)\n",
dvb->name, result);
goto fail_dmxdev;
}
dvb->fe_hw.source = DMX_FRONTEND_0;
result = dvb->demux.dmx.add_frontend(&dvb->demux.dmx, &dvb->fe_hw);
if (result < 0) {
printk(KERN_WARNING "%s: add_frontend failed (DMX_FRONTEND_0, errno = %d)\n",
dvb->name, result);
goto fail_fe_hw;
}
dvb->fe_mem.source = DMX_MEMORY_FE;
result = dvb->demux.dmx.add_frontend(&dvb->demux.dmx, &dvb->fe_mem);
if (result < 0) {
printk(KERN_WARNING "%s: add_frontend failed (DMX_MEMORY_FE, errno = %d)\n",
dvb->name, result);
goto fail_fe_mem;
}
result = dvb->demux.dmx.connect_frontend(&dvb->demux.dmx, &dvb->fe_hw);
if (result < 0) {
printk(KERN_WARNING "%s: connect_frontend failed (errno = %d)\n",
dvb->name, result);
goto fail_fe_conn;
}
/* register network adapter */
dvb_net_init(adapter, &dvb->net, &dvb->demux.dmx);
return 0;
fail_fe_conn:
dvb->demux.dmx.remove_frontend(&dvb->demux.dmx, &dvb->fe_mem);
fail_fe_mem:
dvb->demux.dmx.remove_frontend(&dvb->demux.dmx, &dvb->fe_hw);
fail_fe_hw:
dvb_dmxdev_release(&dvb->dmxdev);
fail_dmxdev:
dvb_dmx_release(&dvb->demux);
fail_dmx:
dvb_unregister_frontend(dvb->frontend);
fail_frontend:
dvb_frontend_detach(dvb->frontend);
dvb_unregister_adapter(adapter);
return result;
}
void videobuf_dvb_unregister_bus(struct videobuf_dvb_frontends *f)
{
struct list_head *list, *q;
struct videobuf_dvb_frontend *fe;
mutex_lock(&f->lock);
list_for_each_safe(list, q, &f->frontend.felist) {
fe = list_entry(list, struct videobuf_dvb_frontend, felist);
dvb_net_release(&fe->dvb.net);
fe->dvb.demux.dmx.remove_frontend(&fe->dvb.demux.dmx, &fe->dvb.fe_mem);
fe->dvb.demux.dmx.remove_frontend(&fe->dvb.demux.dmx, &fe->dvb.fe_hw);
dvb_dmxdev_release(&fe->dvb.dmxdev);
dvb_dmx_release(&fe->dvb.demux);
dvb_unregister_frontend(fe->dvb.frontend);
dvb_frontend_detach(fe->dvb.frontend);
list_del(list);
kfree(fe);
}
mutex_unlock(&f->lock);
dvb_unregister_adapter(&f->adapter);
}
struct videobuf_dvb_frontend * videobuf_dvb_get_frontend(struct videobuf_dvb_frontends *f, int id)
{
struct list_head *list, *q;
struct videobuf_dvb_frontend *fe, *ret = NULL;
mutex_lock(&f->lock);
list_for_each_safe(list, q, &f->frontend.felist) {
fe = list_entry(list, struct videobuf_dvb_frontend, felist);
if (fe->id == id) {
ret = fe;
break;
}
}
mutex_unlock(&f->lock);
return ret;
}
int videobuf_dvb_find_frontend(struct videobuf_dvb_frontends *f, struct dvb_frontend *p)
{
struct list_head *list, *q;
struct videobuf_dvb_frontend *fe = NULL;
int ret = 0;
mutex_lock(&f->lock);
list_for_each_safe(list, q, &f->frontend.felist) {
fe = list_entry(list, struct videobuf_dvb_frontend, felist);
if (fe->dvb.frontend == p) {
ret = fe->id;
break;
}
}
mutex_unlock(&f->lock);
return ret;
}
struct videobuf_dvb_frontend * videobuf_dvb_alloc_frontend(void *private, struct videobuf_dvb_frontends *f, int id)
{
struct videobuf_dvb_frontend *fe;
fe = kzalloc(sizeof(struct videobuf_dvb_frontend),GFP_KERNEL);
if (fe == NULL)
goto fail_alloc;
fe->dev = private;
fe->id = id;
mutex_init(&fe->dvb.lock);
mutex_lock(&f->lock);
list_add_tail(&fe->felist,&f->frontend.felist);
mutex_unlock(&f->lock);
fail_alloc:
return fe;
}
EXPORT_SYMBOL(videobuf_dvb_register_bus);
EXPORT_SYMBOL(videobuf_dvb_unregister_bus);
EXPORT_SYMBOL(videobuf_dvb_alloc_frontend);
EXPORT_SYMBOL(videobuf_dvb_get_frontend);
EXPORT_SYMBOL(videobuf_dvb_find_frontend);
/* ------------------------------------------------------------------ */
/*
* Local variables:
* c-basic-offset: 8
* compile-command: "make DVB=1"
* End:
*/