user/sven/linux.git/include/linux/firewire-cdev.h, branch v3.4.40

firewire: allow explicit flushing of iso packet completions

2012-03-18T21:15:39Z

Extend the kernel and userspace APIs to allow reporting all currently completed isochronous packets, even if the next interrupt packet has not yet been reached. This is required to determine the status of the packets at the end of a paused or stopped stream, and useful for more precise synchronization of audio streams. Signed-off-by: Clemens Ladisch Signed-off-by: Stefan Richter

firewire: prevent dropping of completed iso packet header data

2012-03-18T21:15:39Z

The buffer for the header data of completed iso packets has a fixed size, so it is possible to configure a stream with a big interval between interrupt packets or with big headers so that this buffer would overflow. Previously, ohci.c would drop any data that would not fit, but this could make unsuspecting applications believe that fewer than the actual number of packets have completed. Instead of dropping data, add calls to flush_iso_completion() so that there are as many events as needed to report all of the data. Signed-off-by: Clemens Ladisch Signed-off-by: Stefan Richter

firewire: cdev: fix IR multichannel event documentation

2012-03-17T10:07:26Z

State more precisely when fw_cdev_event_iso_interrupt_mc is sent. While the comment tried to reflect an amibuity in the OHCI specification, there is only one method that is useful in practice, and this also matches all the hardware implementations I've tested. Signed-off-by: Clemens Ladisch Signed-off-by: Stefan Richter

firewire: cdev: ABI documentation enhancements

2011-07-16T05:24:32Z

Add overview documentation in Documentation/ABI/stable/firewire-cdev. Improve the inline reference documentation in firewire-cdev.h: - Add /* available since kernel... */ comments to event numbers consistent with the comments on ioctl numbers. - Shorten some documentation on an event and an ioctl that are less interesting to current programming because there are newer preferable variants. - Spell Configuration ROM (name of an IEEE 1212 register) in upper case. - Move the dummy FW_CDEV_VERSION out of the reader's field of vision. We should remove it from the header next year or so. Signed-off-by: Stefan Richter

firewire: cdev: prevent race between first get_info ioctl and bus reset event queuing

2011-07-16T05:24:32Z

Between open(2) of a /dev/fw* and the first FW_CDEV_IOC_GET_INFO ioctl(2) on it, the kernel already queues FW_CDEV_EVENT_BUS_RESET events to be read(2) by the client. The get_info ioctl is practically always issued right away after open, hence this condition only occurs if the client opens during a bus reset, especially during a rapid series of bus resets. The problem with this condition is twofold: - These bus reset events carry the (as yet undocumented) @closure value of 0. But it is not the kernel's place to choose closures; they are privat to the client. E.g., this 0 value forced from the kernel makes it unsafe for clients to dereference it as a pointer to a closure object without NULL pointer check. - It is impossible for clients to determine the relative order of bus reset events from get_info ioctl(2) versus those from read(2), except in one way: By comparison of closure values. Again, such a procedure imposes complexity on clients and reduces freedom in use of the bus reset closure. So, change the ABI to suppress queuing of bus reset events before the first FW_CDEV_IOC_GET_INFO ioctl was issued by the client. Note, this ABI change cannot be version-controlled. The kernel cannot distinguish old from new clients before the first FW_CDEV_IOC_GET_INFO ioctl. We will try to back-merge this change into currently maintained stable/ longterm series, and we only document the new behaviour. The old behavior is now considered a kernel bug, which it basically is. Signed-off-by: Stefan Richter Cc:

Fix common misspellings

2011-03-31T14:26:23Z

Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi

tree-wide: fix comment/printk typos

2010-11-01T19:38:34Z

"gadget", "through", "command", "maintain", "maintain", "controller", "address", "between", "initiali[zs]e", "instead", "function", "select", "already", "equal", "access", "management", "hierarchy", "registration", "interest", "relative", "memory", "offset", "already", Signed-off-by: Uwe Kleine-König Signed-off-by: Jiri Kosina

Merge firewire branches to be released post v2.6.35

2010-08-02T08:09:04Z

Conflicts: drivers/firewire/core-card.c drivers/firewire/core-cdev.c and forgotten #include in drivers/firewire/ohci.c Signed-off-by: Stefan Richter

firewire: add isochronous multichannel reception

2010-07-29T21:09:18Z

This adds the DMA context programming and userspace ABI for multichannel reception, i.e. for listening on multiple channel numbers by means of a single DMA context. The use case is reception of more streams than there are IR DMA units offered by the link layer. This is already implemented by the older ohci1394 + ieee1394 + raw1394 stack. And as discussed recently on linux1394-devel, this feature is occasionally used in practice. The big drawbacks of this mode are that buffer layout and interrupt generation necessarily differ from single-channel reception: Headers and trailers are not stripped from packets, packets are not aligned with buffer chunks, interrupts are per buffer chunk, not per packet. These drawbacks also cause a rather hefty code footprint to support this rarely used OHCI-1394 feature. (367 lines added, among them 94 lines of added userspace ABI documentation.) This implementation enforces that a multichannel reception context may only listen to channels to which no single-channel context on the same link layer is presently listening to. OHCI-1394 would allow to overlay single-channel contexts by the multi-channel context, but this would be a departure from the present first-come-first-served policy of IR context creation. The implementation is heavily based on an earlier one by Jay Fenlason. Thanks Jay. Signed-off-by: Stefan Richter

firewire: cdev: improve FW_CDEV_IOC_ALLOCATE

2010-07-23T11:36:28Z

In both the ieee1394 stack and the firewire stack, the core treats kernelspace drivers better than userspace drivers when it comes to CSR address range allocation: The former may request a register to be placed automatically at a free spot anywhere inside a specified address range. The latter may only request a register at a fixed offset. Hence, userspace drivers which do not require a fixed offset potentially need to implement a retry loop with incremented offset in each retry until the kernel does not fail allocation with EBUSY. This awkward procedure is not fundamentally necessary as the core already provides a superior allocation API to kernelspace drivers. Therefore change the ioctl() ABI by addition of a region_end member in the existing struct fw_cdev_allocate. Userspace and kernelspace APIs work the same way now. There is a small cost to pay by clients though: If client source code is required to compile with older kernel headers too, then any use of the new member fw_cdev_allocate.region_end needs to be enclosed by #ifdef/#endif directives. However, any client program that seriously wants to use address range allocations will require a kernel of cdev ABI version >= 4 at runtime and a linux/firewire-cdev.h header of >= 4 anyway. This is because v4 brings FW_CDEV_EVENT_REQUEST2. The only client program in which build-time compatibility with struct fw_cdev_allocate as found in older kernel headers makes sense is libraw1394. (libraw1394 uses the older broken FW_CDEV_EVENT_REQUEST to implement a makeshift, incorrect transaction responder that does at least work somewhat in many simple scenarios, relying on guesswork by libraw1394 and by libraw1394 based applications. Plus, address range allocation and transaction responder is only one of many features that libraw1394 needs to provide, and these other features need to work with kernel and kernel-headers as old as possible. Any new linux/firewire-cdev.h based client that implements a transaction responder should never attempt to do it like libraw1394; instead it should make a header and kernel of v4 or later a hard requirement.) While we are at it, update the struct fw_cdev_allocate documentation to better reflect the recent fw_cdev_event_request2 ABI addition. Signed-off-by: Stefan Richter