Commit 1ec3c026 authored by Stefan Richter's avatar Stefan Richter
Browse files

firewire: cdev: add ioctls for manual iso resource management 



This adds ioctls for allocation and deallocation of a channel or/and
bandwidth without auto-reallocation and without auto-deallocation.

The benefit of these ioctls is that libraw1394-style isochronous
resource management can be implemented without write access to the IRM's
character device file.

Signed-off-by: default avatarStefan Richter <stefanr@s5r6.in-berlin.de>
parent b1bda4cd

drivers/firewire/fw-cdev.c

+54 −13
Original line number Diff line number Diff line
@@ -121,14 +121,15 @@ struct iso_resource { 
	struct client *client;

	/* Schedule work and access todo only with client->lock held. */

	struct delayed_work work;

	enum {ISO_RES_ALLOC, ISO_RES_REALLOC, ISO_RES_DEALLOC,} todo;

	enum {ISO_RES_ALLOC, ISO_RES_REALLOC, ISO_RES_DEALLOC,

	      ISO_RES_ALLOC_ONCE, ISO_RES_DEALLOC_ONCE,} todo;

	int generation;

	u64 channels;

	s32 bandwidth;

	struct iso_resource_event *e_alloc, *e_dealloc;

};



static void schedule_iso_resource(struct iso_resource *);

static int schedule_iso_resource(struct iso_resource *);

static void release_iso_resource(struct client *, struct client_resource *);



/*
@@ -1033,7 +1034,9 @@ static void iso_resource_work(struct work_struct *work) 
		skip = todo == ISO_RES_REALLOC &&

		       r->generation == generation;

	}

	free = todo == ISO_RES_DEALLOC;

	free = todo == ISO_RES_DEALLOC ||

	       todo == ISO_RES_ALLOC_ONCE ||

	       todo == ISO_RES_DEALLOC_ONCE;

	r->generation = generation;

	spin_unlock_irq(&client->lock);
@@ -1044,7 +1047,9 @@ static void iso_resource_work(struct work_struct *work) 


	fw_iso_resource_manage(client->device->card, generation,

			r->channels, &channel, &bandwidth,

			todo == ISO_RES_ALLOC || todo == ISO_RES_REALLOC);

			todo == ISO_RES_ALLOC ||

			todo == ISO_RES_REALLOC ||

			todo == ISO_RES_ALLOC_ONCE);

	/*

	 * Is this generation outdated already?  As long as this resource sticks

	 * in the idr, it will be scheduled again for a newer generation or at
@@ -1082,7 +1087,7 @@ static void iso_resource_work(struct work_struct *work) 
	if (todo == ISO_RES_REALLOC && success)

		goto out;



	if (todo == ISO_RES_ALLOC) {

	if (todo == ISO_RES_ALLOC || todo == ISO_RES_ALLOC_ONCE) {

		e = r->e_alloc;

		r->e_alloc = NULL;

	} else {
@@ -1106,10 +1111,17 @@ static void iso_resource_work(struct work_struct *work) 
	client_put(client);

}



static void schedule_iso_resource(struct iso_resource *r)

static int schedule_iso_resource(struct iso_resource *r)

{

	if (schedule_delayed_work(&r->work, 0))

	int scheduled;



	client_get(r->client);



	scheduled = schedule_delayed_work(&r->work, 0);

	if (!scheduled)

		client_put(r->client);



	return scheduled;

}



static void release_iso_resource(struct client *client,
@@ -1124,9 +1136,9 @@ static void release_iso_resource(struct client *client, 
	spin_unlock_irq(&client->lock);

}



static int ioctl_allocate_iso_resource(struct client *client, void *buffer)

static int init_iso_resource(struct client *client,

		struct fw_cdev_allocate_iso_resource *request, int todo)

{

	struct fw_cdev_allocate_iso_resource *request = buffer;

	struct iso_resource_event *e1, *e2;

	struct iso_resource *r;

	int ret;
@@ -1146,7 +1158,7 @@ static int ioctl_allocate_iso_resource(struct client *client, void *buffer) 


	INIT_DELAYED_WORK(&r->work, iso_resource_work);

	r->client	= client;

	r->todo		= ISO_RES_ALLOC;

	r->todo		= todo;

	r->generation	= -1;

	r->channels	= request->channels;

	r->bandwidth	= request->bandwidth;
@@ -1158,8 +1170,14 @@ static int ioctl_allocate_iso_resource(struct client *client, void *buffer) 
	e2->resource.closure	= request->closure;

	e2->resource.type	= FW_CDEV_EVENT_ISO_RESOURCE_DEALLOCATED;



	if (todo == ISO_RES_ALLOC) {

		r->resource.release = release_iso_resource;

		ret = add_client_resource(client, &r->resource, GFP_KERNEL);

	} else {

		r->resource.release = NULL;

		r->resource.handle = -1;

		ret = schedule_iso_resource(r) ? 0 : -ENOMEM;

	}

	if (ret < 0)

		goto fail;

	request->handle = r->resource.handle;
@@ -1173,6 +1191,13 @@ static int ioctl_allocate_iso_resource(struct client *client, void *buffer) 
	return ret;

}



static int ioctl_allocate_iso_resource(struct client *client, void *buffer)

{

	struct fw_cdev_allocate_iso_resource *request = buffer;



	return init_iso_resource(client, request, ISO_RES_ALLOC);

}



static int ioctl_deallocate_iso_resource(struct client *client, void *buffer)

{

	struct fw_cdev_deallocate *request = buffer;
@@ -1181,6 +1206,20 @@ static int ioctl_deallocate_iso_resource(struct client *client, void *buffer) 
				       release_iso_resource, NULL);

}



static int ioctl_allocate_iso_resource_once(struct client *client, void *buffer)

{

	struct fw_cdev_allocate_iso_resource *request = buffer;



	return init_iso_resource(client, request, ISO_RES_ALLOC_ONCE);

}



static int ioctl_deallocate_iso_resource_once(struct client *client, void *buffer)

{

	struct fw_cdev_allocate_iso_resource *request = buffer;



	return init_iso_resource(client, request, ISO_RES_DEALLOC_ONCE);

}



static int (* const ioctl_handlers[])(struct client *client, void *buffer) = {

	ioctl_get_info,

	ioctl_send_request,
@@ -1197,6 +1236,8 @@ static int (* const ioctl_handlers[])(struct client *client, void *buffer) = { 
	ioctl_get_cycle_timer,

	ioctl_allocate_iso_resource,

	ioctl_deallocate_iso_resource,

	ioctl_allocate_iso_resource_once,

	ioctl_deallocate_iso_resource_once,

};



static int dispatch_ioctl(struct client *client,

include/linux/firewire-cdev.h

+32 −10
Original line number Diff line number Diff line
@@ -151,7 +151,7 @@ struct fw_cdev_event_iso_interrupt { 
/**

 * struct fw_cdev_event_iso_resource - Iso resources were allocated or freed

 * @closure:	See &fw_cdev_event_common;

 *		set by %FW_CDEV_IOC_ALLOCATE_ISO_RESOURCE ioctl

 *		set by %FW_CDEV_IOC_(DE)ALLOCATE_ISO_RESOURCE(_ONCE) ioctl

 * @type:	%FW_CDEV_EVENT_ISO_RESOURCE_ALLOCATED or

 *		%FW_CDEV_EVENT_ISO_RESOURCE_DEALLOCATED

 * @handle:	Reference by which an allocated resource can be deallocated
@@ -164,12 +164,12 @@ struct fw_cdev_event_iso_interrupt { 
 * resource was allocated at the IRM.  The client has to check @channel and

 * @bandwidth for whether the allocation actually succeeded.

 *

 * @channel is <0 if no channel was allocated.

 * @bandwidth is 0 if no bandwidth was allocated.

 *

 * An %FW_CDEV_EVENT_ISO_RESOURCE_DEALLOCATED event is sent after an isochronous

 * resource was deallocated at the IRM.  It is also sent when automatic

 * reallocation after a bus reset failed.

 *

 * @channel is <0 if no channel was (de)allocated or if reallocation failed.

 * @bandwidth is 0 if no bandwidth was (de)allocated or if reallocation failed.

 */

struct fw_cdev_event_iso_resource {

	__u64 closure;
@@ -227,6 +227,8 @@ union fw_cdev_event { 
/* available since kernel version 2.6.30 */

#define FW_CDEV_IOC_ALLOCATE_ISO_RESOURCE       _IOWR('#', 0x0d, struct fw_cdev_allocate_iso_resource)

#define FW_CDEV_IOC_DEALLOCATE_ISO_RESOURCE      _IOW('#', 0x0e, struct fw_cdev_deallocate)

#define FW_CDEV_IOC_ALLOCATE_ISO_RESOURCE_ONCE   _IOW('#', 0x0f, struct fw_cdev_allocate_iso_resource)

#define FW_CDEV_IOC_DEALLOCATE_ISO_RESOURCE_ONCE _IOW('#', 0x10, struct fw_cdev_allocate_iso_resource)



/* FW_CDEV_VERSION History

 *
@@ -523,11 +525,12 @@ struct fw_cdev_get_cycle_timer { 
};



/**

 * struct fw_cdev_allocate_iso_resource - Allocate a channel or bandwidth

 * struct fw_cdev_allocate_iso_resource - (De)allocate a channel or bandwidth

 * @closure:	Passed back to userspace in correponding iso resource events

 * @channels:	Isochronous channels of which one is to be allocated

 * @bandwidth:	Isochronous bandwidth units to be allocated

 * @handle:	Handle to the allocation, written by the kernel

 * @channels:	Isochronous channels of which one is to be (de)allocated

 * @bandwidth:	Isochronous bandwidth units to be (de)allocated

 * @handle:	Handle to the allocation, written by the kernel (only valid in

 *		case of %FW_CDEV_IOC_ALLOCATE_ISO_RESOURCE ioctls)

 *

 * The %FW_CDEV_IOC_ALLOCATE_ISO_RESOURCE ioctl initiates allocation of an

 * isochronous channel and/or of isochronous bandwidth at the isochronous
@@ -539,6 +542,25 @@ struct fw_cdev_get_cycle_timer { 
 * will be sent.  The kernel will also automatically deallocate the resources

 * when the file descriptor is closed.

 *

 * The %FW_CDEV_IOC_DEALLOCATE_ISO_RESOURCE ioctl can be used to initiate

 * deallocation of resources which were allocated as described above.

 * An %FW_CDEV_EVENT_ISO_RESOURCE_DEALLOCATED event concludes this operation.

 *

 * The %FW_CDEV_IOC_ALLOCATE_ISO_RESOURCE_ONCE ioctl is a variant of allocation

 * without automatic re- or deallocation.

 * An %FW_CDEV_EVENT_ISO_RESOURCE_ALLOCATED event concludes this operation,

 * indicating success or failure in its data.

 *

 * The %FW_CDEV_IOC_DEALLOCATE_ISO_RESOURCE_ONCE ioctl works like

 * %FW_CDEV_IOC_ALLOCATE_ISO_RESOURCE_ONCE except that resources are freed

 * instead of allocated.  At most one channel may be specified in this ioctl.

 * An %FW_CDEV_EVENT_ISO_RESOURCE_DEALLOCATED event concludes this operation.

 *

 * To summarize, %FW_CDEV_IOC_DEALLOCATE_ISO_RESOURCE allocates iso resources

 * for the lifetime of the fd or handle.

 * In contrast, %FW_CDEV_IOC_ALLOCATE_ISO_RESOURCE_ONCE allocates iso resources

 * for the duration of a bus generation.

 *

 * @channels is a host-endian bitfield with the most significant bit

 * representing channel 0 and the least significant bit representing channel 63:

 * 1ULL << (63 - c)

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