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staging: most: add poll syscall to AIM cdev

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This patch adds the implementation of the poll syscall to the AIM cdev.
To have the full functionality, a helper function is needed in the
core module to retrieve the instantaneous availability of tx buffers.

Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Christian Gromm 2015-09-28 17:18:57 +02:00 committed by Greg Kroah-Hartman
parent 48ab5a339d
commit aac997dfdd
3 changed files with 43 additions and 0 deletions
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26
drivers/staging/most/aim-cdev/cdev.c
View file

@ -18,6 +18,7 @@
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/cdev.h>
#include <linux/poll.h>
#include <linux/kfifo.h>
#include <linux/uaccess.h>
#include <linux/idr.h>
@ -31,6 +32,7 @@ static struct most_aim cdev_aim;
struct aim_channel {
wait_queue_head_t wq;
wait_queue_head_t poll_wq;
struct cdev cdev;
struct device *dev;
struct mutex io_mutex;
@ -271,6 +273,28 @@ start_copy:
return retval;
}
static inline bool __must_check IS_ERR_OR_FALSE(int x)
{
return x <= 0;
}
static unsigned int aim_poll(struct file *filp, poll_table *wait)
{
struct aim_channel *c = filp->private_data;
unsigned int mask = 0;
poll_wait(filp, &c->poll_wq, wait);
if (c->cfg->direction == MOST_CH_RX) {
if (!kfifo_is_empty(&c->fifo))
mask |= POLLIN | POLLRDNORM;
} else {
if (!IS_ERR_OR_FALSE(channel_has_mbo(c->iface, c->channel_id)))
mask |= POLLOUT | POLLWRNORM;
}
return mask;
}
/**
* Initialization of struct file_operations
*/
@ -280,6 +304,7 @@ static const struct file_operations channel_fops = {
.write = aim_write,
.open = aim_open,
.release = aim_close,
.poll = aim_poll,
};
/**
@ -434,6 +459,7 @@ static int aim_probe(struct most_interface *iface, int channel_id,
goto error_alloc_kfifo;
}
init_waitqueue_head(&channel->wq);
init_waitqueue_head(&channel->poll_wq);
mutex_init(&channel->io_mutex);
spin_lock_irqsave(&ch_list_lock, cl_flags);
list_add_tail(&channel->list, &channel_list);

16
drivers/staging/most/mostcore/core.c
View file

@ -1383,6 +1383,22 @@ most_c_obj *get_channel_by_iface(struct most_interface *iface, int id)
return i->channel[id];
}
int channel_has_mbo(struct most_interface *iface, int id)
{
struct most_c_obj *c = get_channel_by_iface(iface, id);
unsigned long flags;
int empty;
if (unlikely(!c))
return -EINVAL;
spin_lock_irqsave(&c->fifo_lock, flags);
empty = list_empty(&c->fifo);
spin_unlock_irqrestore(&c->fifo_lock, flags);
return !empty;
}
EXPORT_SYMBOL_GPL(channel_has_mbo);
/**
* most_get_mbo - get pointer to an MBO of pool
* @iface: pointer to interface instance

1
drivers/staging/most/mostcore/mostcore.h
View file

@ -311,6 +311,7 @@ int most_deregister_aim(struct most_aim *aim);
struct mbo *most_get_mbo(struct most_interface *iface, int channel_idx,
struct most_aim *);
void most_put_mbo(struct mbo *mbo);
int channel_has_mbo(struct most_interface *iface, int channel_idx);
int most_start_channel(struct most_interface *iface, int channel_idx,
struct most_aim *);
int most_stop_channel(struct most_interface *iface, int channel_idx,