Standardize on if (err)
handle_error;
and if (ret < 0)
handle_error;
Don't call a variable err if we store values in it which mean success.
Also, offset some return statements by a blank line since this how we do
it in drivers/firewire.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
reread_bus_info_block() only gets to see devices whose config_rom_length
is at least 6 (ROM header, bus info block, root directory header).
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
The kernel API documentation says that queue_delayed_work() returns 0
(only) if the work was already queued. The return codes of
schedule_delayed_work() are not documented but the same.
In init_iso_resource(), the work has never been queued yet, hence we
can assume schedule_delayed_work() to be a guaranteed success there.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Some fixes:
- Remove stale documentation.
- Fix a != vs. == thinko that got in the way of channel management.
- Try bandwidth deallocation even if channel deallocation failed.
A simplification:
- fw_cdev_allocate_iso_resource.channels is now ordered like
libdc1394's dc1394_iso_allocate_channel() channels_allowed
argument.
By the way, I looked closer at cards from NEC, TI, and VIA, and noticed
that they all don't implement IEEE 1394a behaviour which is meant to
deviate from IEEE 1212's notion of lock compare-swap. This means that
we have to do two lock transactions instead of one in many cases where
one transaction would already succeed on a fully 1394a compliant IRM.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Necessary due to
Date: Tue, 22 Jul 2008 23:23:40 -0700
From: David Moore <dcm@acm.org>
Subject: firewire: Include iso timestamp in headers when header_size > 4
Side note: The lack of upwards compatibility sounds worse than it is.
All existing client implementations, libraw1394 and libdc1394, set
header_size = 4. And since the ABI v1 behaviour does not offer any
advantages over the new behaviour, we deliberately do not provide the
old behaviour anymore.
Also add documentation about the format of fw_cdev_get_cycle_timer which
may be used in conjunction with the timestamp of iso packets but has a
different format.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
DMA must be halted before we DMA-unmap and free the DMA buffer. Since
we cannot rely on the client to stop the context before it closes the
fd, we have to reorder fw_iso_buffer_destroy vs. fw_iso_context_destroy.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
All of these functions are entered with IRQs enabled.
Hence the unconditional spin_unlock_irq can be used.
Function: Caller context:
dequeue_event() client process, via read(2)
fill_bus_reset_event() fw-device.c update worqueue job
release_client_resource() client process, via ioctl(2)
fw_device_op_release() client process, via close(2)
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Make the size check of ioctl_send_request and
ioctl_send_broadcast_request speed dependent. Also change the error
return code from -EINVAL to -EIO to distinguish this from other errors
concerning the ioctl parameters.
Another payload size limit for which we don't check here though is the
remote node's Bus_Info_Block.max_rec.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
We don't want random users write to Memory Space (e.g. PCs with physical
DMA filters down) or to core CSRs like Reset_Start.
This does not protect SBP-2 target CSRs. But properly behaving SBP-2
targets ignore broadcast write requests to these registers, and the
maximum damage which can happen with laxer targets is DOS. But there
are ways to create DOS situations anyway if there are devices with weak
device file permissions (like audio/video devices) present at the same
bus as an SBP-2 target.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Write transactions to the broadcast node ID are a convenient way to
trigger functions of multiple nodes at once. IIDC is a protocol which
can make use of this if multiple cameras with same command_regs_base are
connected at the same bus.
Based on
Date: Wed, 10 Sep 2008 11:32:16 -0400
From: Jay Fenlason <fenlason@redhat.com>
Subject: [patch] SEND_BROADCAST_REQUEST
Changes: ioctl_send_request() and ioctl_send_broadcast_request() now
share code. Broadcast speed corrected to S100. Check for proper tcode.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
While the speed of asynchronous transactions is automatically chosen by
the kernel, the speed of isochronous streams has to be chosen by the
initiating client.
In case of 1394a bus topologies, the maximum possible speed could be
figured out with some effort by evaluation of the remote node's link
speed field in the config ROM, the local node's link speed field, and
the PHY speeds and topologic information in the local node's or IRM's
topology map CSR. However, this does not work in case of 1394b buses.
Hence add an ioctl to export the maximum speed which the kernel already
determined.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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 <stefanr@s5r6.in-berlin.de>
Based on
Date: Tue, 18 Nov 2008 11:41:27 -0500
From: Jay Fenlason <fenlason@redhat.com>
Subject: [Patch V4] Add ISO resource management support
with several changes to the ABI and implementation. Only the part of
the ABI which enables auto-reallocation and auto-deallocation is
included here.
This implements ioctls for kernel-assisted allocation of isochronous
channels and isochronous bandwidth. The benefits are:
- The client does not have to have write access to the /dev/fw* device
corresponding to the IRM.
- The client does not have to perform reallocation after bus resets.
- Channel and bandwidth are deallocated by the kernel if the file is
closed before the client deallocated the resources. Thus resources
are released even if the client crashes.
It is anticipated that future in-kernel code (firewire-core IRM code;
the firewire port of firedtv), will use the fw-iso.c portions of this
code too.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Tested-by: David Moore <dcm@acm.org>
to indicate that they are specializations of struct event or of struct
client_resource, respectively.
struct response was both an event and a client_resource; it is now split
into struct outbound_transaction_resource and ~_event in order to
document more explicitly which types of client resources exist.
struct request and struct_request_event are renamed to struct
inbound_transaction_resource and ~_event because requests and responses
occur in outbound and in inbound transactions.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
The lifetime of struct client instances must be longer than the lifetime
of any client resource.
This fixes a possible race between fw_device_op_release and transaction
completions. It also prepares for new ioctls for isochronous resource
management which will involve delayed processing of client resources.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Reviewed-by: David Moore <dcm@acm.org>
The FW_CDEV_IOC_GET_INFO ioctl looks at client->device->config_rom, not
at the local node's config ROM.
We could fix the implementation or the documentation. I believe the way
how it is currently implemented is more useful than the way how it is
currently documented. In fact, libdc1394 uses the ABI already as
implemented, not as documented. Hence let's change the documentation.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
OHCI-1394 1.1 clause 10.4.3 says: "If more than one IR DMA context
specifies receives for packets from the same isochronous channel, the
context destination for that channel's packets is undefined."
Any userspace client and in the future also kernelspace clients can
allocate IR DMA contexts for any channel. We don't want them to
interfere with each other, hence it is preferable to return -EBUSY if
allocation of a second context for a channel is attempted.
Notes:
- This limitation is OHCI-1394 specific, therefore its proper place of
implementation is down in the low-level driver.
- Since the <linux/firewire-cdev.h> ABI simply maps one userspace iso
client context to one hardware iso context, this OHCI-1394
limitation alas requires userspace to implement its own multiplexing
of iso reception from the same channel and card to multiple clients
when needed.
- The limitation is independent of channel allocation at the IRM; the
latter is really only important for the initiation of iso
transmission but not of iso reception.
- We don't need to do the same for IT DMA because OHCI-1394 does not
have any ties between IT contexts and channels. Only the voluntary
channel allocation protocol via the IRM, globally to the FireWire
bus, can ensure proper isochronous transmit behaviour anyway.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Stefan Richter