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>
diff --git a/drivers/media/dvb/dvb-core/dvb_frontend.c b/drivers/media/dvb/dvb-core/dvb_frontend.c
index 2667175..62696f8 100644
--- a/drivers/media/dvb/dvb-core/dvb_frontend.c
+++ b/drivers/media/dvb/dvb-core/dvb_frontend.c
@@ -47,6 +47,7 @@
static int dvb_force_auto_inversion;
static int dvb_override_tune_delay;
static int dvb_powerdown_on_sleep = 1;
+static int dvb_mfe_wait_time = 5;
module_param_named(frontend_debug, dvb_frontend_debug, int, 0644);
MODULE_PARM_DESC(frontend_debug, "Turn on/off frontend core debugging (default:off).");
@@ -58,6 +59,8 @@
MODULE_PARM_DESC(dvb_override_tune_delay, "0: normal (default), >0 => delay in milliseconds to wait for lock after a tune attempt");
module_param(dvb_powerdown_on_sleep, int, 0644);
MODULE_PARM_DESC(dvb_powerdown_on_sleep, "0: do not power down, 1: turn LNB voltage off on sleep (default)");
+module_param(dvb_mfe_wait_time, int, 0644);
+MODULE_PARM_DESC(dvb_mfe_wait_time, "Wait up to <mfe_wait_time> seconds on open() for multi-frontend to become available (default:5 seconds)");
#define dprintk if (dvb_frontend_debug) printk
@@ -1706,13 +1709,46 @@
struct dvb_device *dvbdev = file->private_data;
struct dvb_frontend *fe = dvbdev->priv;
struct dvb_frontend_private *fepriv = fe->frontend_priv;
+ struct dvb_adapter *adapter = fe->dvb;
+ struct dvb_device *mfedev;
+ struct dvb_frontend *mfe;
+ struct dvb_frontend_private *mfepriv;
+ int mferetry;
int ret;
dprintk ("%s\n", __func__);
+ if (adapter->mfe_shared) {
+ mutex_lock (&adapter->mfe_lock);
+ if (adapter->mfe_dvbdev != dvbdev) {
+ if (adapter->mfe_dvbdev) {
+ mfedev = adapter->mfe_dvbdev;
+ mfe = mfedev->priv;
+ mfepriv = mfe->frontend_priv;
+ mutex_unlock (&adapter->mfe_lock);
+ mferetry = (dvb_mfe_wait_time << 1);
+ while (mferetry-- && (mfedev->users != -1 || mfepriv->thread != NULL)) {
+ if(msleep_interruptible(500)) {
+ if(signal_pending(current))
+ return -EINTR;
+ }
+ }
+ mutex_lock (&adapter->mfe_lock);
+ mfedev = adapter->mfe_dvbdev;
+ mfe = mfedev->priv;
+ mfepriv = mfe->frontend_priv;
+ if (mfedev->users != -1 || mfepriv->thread != NULL) {
+ ret = -EBUSY;
+ goto err0;
+ }
+ }
+ adapter->mfe_dvbdev = dvbdev;
+ }
+ }
+
if (dvbdev->users == -1 && fe->ops.ts_bus_ctrl) {
if ((ret = fe->ops.ts_bus_ctrl(fe, 1)) < 0)
- return ret;
+ goto err0;
}
if ((ret = dvb_generic_open (inode, file)) < 0)
@@ -1732,6 +1768,8 @@
fepriv->events.eventr = fepriv->events.eventw = 0;
}
+ if (adapter->mfe_shared)
+ mutex_unlock (&adapter->mfe_lock);
return ret;
err2:
@@ -1739,6 +1777,9 @@
err1:
if (dvbdev->users == -1 && fe->ops.ts_bus_ctrl)
fe->ops.ts_bus_ctrl(fe, 0);
+err0:
+ if (adapter->mfe_shared)
+ mutex_unlock (&adapter->mfe_lock);
return ret;
}
diff --git a/drivers/media/dvb/dvb-core/dvbdev.c b/drivers/media/dvb/dvb-core/dvbdev.c
index 665776d..a113744 100644
--- a/drivers/media/dvb/dvb-core/dvbdev.c
+++ b/drivers/media/dvb/dvb-core/dvbdev.c
@@ -326,6 +326,9 @@
adap->name = name;
adap->module = module;
adap->device = device;
+ adap->mfe_shared = 0;
+ adap->mfe_dvbdev = NULL;
+ mutex_init (&adap->mfe_lock);
list_add_tail (&adap->list_head, &dvb_adapter_list);
diff --git a/drivers/media/dvb/dvb-core/dvbdev.h b/drivers/media/dvb/dvb-core/dvbdev.h
index 89d12dc..574e336 100644
--- a/drivers/media/dvb/dvb-core/dvbdev.h
+++ b/drivers/media/dvb/dvb-core/dvbdev.h
@@ -62,6 +62,10 @@
struct device *device;
struct module *module;
+
+ int mfe_shared; /* indicates mutually exclusive frontends */
+ struct dvb_device *mfe_dvbdev; /* frontend device in use */
+ struct mutex mfe_lock; /* access lock for thread creation */
};
diff --git a/drivers/media/video/cx23885/cx23885-dvb.c b/drivers/media/video/cx23885/cx23885-dvb.c
index c14878f..7885152 100644
--- a/drivers/media/video/cx23885/cx23885-dvb.c
+++ b/drivers/media/video/cx23885/cx23885-dvb.c
@@ -556,7 +556,7 @@
/* register everything */
return videobuf_dvb_register_bus(&port->frontends, THIS_MODULE, port,
- &dev->pci->dev, adapter_nr);
+ &dev->pci->dev, adapter_nr, 0);
}
diff --git a/drivers/media/video/cx88/cx88-dvb.c b/drivers/media/video/cx88/cx88-dvb.c
index 9bb7bee..0dd0ff9 100644
--- a/drivers/media/video/cx88/cx88-dvb.c
+++ b/drivers/media/video/cx88/cx88-dvb.c
@@ -594,14 +594,9 @@
static int dvb_register(struct cx8802_dev *dev)
{
- //struct cx88_core *core = dev->core;
-
- ///* init struct videobuf_dvb */
- //fe->dvb.name = core->name;
- //dev->ts_gen_cntrl = 0x0c;
-
struct cx88_core *core = dev->core;
struct videobuf_dvb_frontend *fe0, *fe1 = NULL;
+ int mfe_shared = 0; /* bus not shared by default */
/* Get the first frontend */
fe0 = videobuf_dvb_get_frontend(&dev->frontends, 1);
@@ -669,6 +664,7 @@
fe1 = videobuf_dvb_get_frontend(&dev->frontends, 2);
if (fe1) {
dev->frontends.gate = 2;
+ mfe_shared = 1;
fe1->dvb.frontend = dvb_attach(cx22702_attach,
&hauppauge_hvr_config,
&dev->core->i2c_adap);
@@ -1013,6 +1009,7 @@
fe1 = videobuf_dvb_get_frontend(&dev->frontends, 2);
if (fe1) {
dev->frontends.gate = 2;
+ mfe_shared = 1;
fe1->dvb.frontend = dvb_attach(cx22702_attach,
&hauppauge_hvr_config,
&dev->core->i2c_adap);
@@ -1110,7 +1107,7 @@
/* register everything */
return videobuf_dvb_register_bus(&dev->frontends, THIS_MODULE, dev,
- &dev->pci->dev, adapter_nr);
+ &dev->pci->dev, adapter_nr, mfe_shared);
frontend_detach:
if (fe0->dvb.frontend) {
diff --git a/drivers/media/video/saa7134/saa7134-dvb.c b/drivers/media/video/saa7134/saa7134-dvb.c
index 30ae0cb..d2d2389 100644
--- a/drivers/media/video/saa7134/saa7134-dvb.c
+++ b/drivers/media/video/saa7134/saa7134-dvb.c
@@ -1395,7 +1395,7 @@
/* register everything else */
ret = videobuf_dvb_register_bus(&dev->frontends, THIS_MODULE, dev,
- &dev->pci->dev, adapter_nr);
+ &dev->pci->dev, adapter_nr, 0);
/* this sequence is necessary to make the tda1004x load its firmware
* and to enter analog mode of hybrid boards
diff --git a/drivers/media/video/videobuf-dvb.c b/drivers/media/video/videobuf-dvb.c
index a0a80e1..af0b75c 100644
--- a/drivers/media/video/videobuf-dvb.c
+++ b/drivers/media/video/videobuf-dvb.c
@@ -140,7 +140,8 @@
struct module *module,
void *adapter_priv,
struct device *device,
- short *adapter_nr) //NEW
+ short *adapter_nr,
+ int mfe_shared)
{
struct list_head *list, *q;
struct videobuf_dvb_frontend *fe;
@@ -153,7 +154,7 @@
}
/* Bring up the adapter */
- res = videobuf_dvb_register_adapter(f, module, adapter_priv, device, fe->dvb.name, adapter_nr); //NEW
+ 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;
@@ -181,7 +182,8 @@
void *adapter_priv,
struct device *device,
char *adapter_name,
- short *adapter_nr) //NEW
+ short *adapter_nr,
+ int mfe_shared)
{
int result;
@@ -194,6 +196,7 @@
adapter_name, result);
}
fe->adapter.priv = adapter_priv;
+ fe->adapter.mfe_shared = mfe_shared;
return result;
}