Date: Sun, 4 Jan 2009 16:23:29 +0100 (CET) From: Stefan Richter Subject: 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: Stefan Richter --- drivers/firewire/fw-cdev.c | 67 +++++++++++++++++++++++++++------- include/linux/firewire-cdev.h | 42 ++++++++++++++++----- 2 files changed, 86 insertions(+), 23 deletions(-) Index: linux/include/linux/firewire-cdev.h =================================================================== --- linux.orig/include/linux/firewire-cdev.h +++ linux/include/linux/firewire-cdev.h @@ -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; @@ -225,8 +225,10 @@ union fw_cdev_event { #define FW_CDEV_IOC_GET_CYCLE_TIMER _IOR('#', 0x0c, struct fw_cdev_get_cycle_timer) /* 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 _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) Index: linux/drivers/firewire/fw-cdev.c =================================================================== --- linux.orig/drivers/firewire/fw-cdev.c +++ linux/drivers/firewire/fw-cdev.c @@ -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 wor 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 wor 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 wor 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 wor 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)) - client_get(r->client); + 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 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(s 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(s e2->resource.closure = request->closure; e2->resource.type = FW_CDEV_EVENT_ISO_RESOURCE_DEALLOCATED; - r->resource.release = release_iso_resource; - ret = add_client_resource(client, &r->resource, GFP_KERNEL); + 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(s 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 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[])(st 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,