android_kernel_xiaomi_sm8350/drivers/firewire
Jarod Wilson a186b4a6b2 firewire: OHCI 1.0 Isochronous Receive support
Third rendition of FireWire OHCI 1.0 Isochronous Receive support, using a
zer-copy method similar to OHCI 1.1 which puts the IR data payload directly
into the userspace buffer. The zero-copy implementation eliminates the
video artifacts, audio popping, and buffer underrun problems seen with
version 1 of this patch, as well as fixing a regression in OHCI 1.1 support
introduced by version 2 of this patch.

Successfully tested in OHCI 1.1 mode on the following chipsets:

- NEC uPD72847 (rev 01), OHCI 1.1 (PCI)
- Ti XIO2200(A) (rev 01), OHCI 1.1 (PCIe)
- Ti TSB41AB2 (rev 01), OHCI 1.1 (PCI on SB Audigy)
- Apple UniNorth 2 (rev 81), OHCI 1.1 (PowerBook G4 onboard)

Successfully tested in OHCI 1.0 mode on the following chipsets:

- Agere FW323 (rev 06), OHCI 1.0 (Mac Mini onboard)
- Agere FW323 (rev 06), OHCI 1.0 (PCI)
- Via VT6306 (rev 46), OHCI 1.0 (PCI)
- NEC OrangeLink (rev 01), OHCI 1.0 (PCI)
- NEC uPD72847 (rev 01), OHCI 1.1 (PCI)
- Ti XIO2200(A) (rev 01), OHCI 1.1 (PCIe)

The bulk of testing was done in an x86_64 system, but was also successfully
sanity-tested on other systems, including a PPC(32) PowerBook G4 and an i686
EPIA M10k. Crude benchmarking (watching top during capture) puts the cpu
utilization during capture on the EPIA's 1GHz Via C3 processor around 13%,
which is down from 30% with the v1 code.

Some implementation details:

To maintain the same userspace API as dual-buffer mode, we set up two
descriptors for every incoming packet. The first is an INPUT_MORE descriptor,
pointing to a buffer large enough to hold just the packet's iso headers,
immediately followed by an INPUT_LAST descriptor, pointing to a chunk of the
userspace buffer big enough for the packet's data payload. With this setup,
each incoming packet fills in these two descriptors in a manner that very
closely emulates dual-buffer receive, to the point where the bulk of the
handle_ir_* code is now identical between the two (and probably primed for
some restructuring to share code between them).

The only caveat I have at the moment is that neither of my OHCI 1.0 Via
VT6307-based FireWire controllers work particularly well with this code
for reasons I have yet to figure out.

Signed-off-by: Jarod Wilson <jwilson@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2007-12-10 21:55:19 +01:00
..
fw-card.c firewire: fix unloading of fw-ohci while devices are attached 2007-08-25 18:00:27 +02:00
fw-cdev.c firewire: fw-cdev: reorder wakeup vs. spinlock 2007-10-17 00:00:10 +02:00
fw-device.c Driver core: change add_uevent_var to use a struct 2007-10-12 14:51:01 -07:00
fw-device.h firewire: fw-sbp2: add support for multiple logical units per target 2007-10-17 00:00:03 +02:00
fw-iso.c firewire: Clean up comment style. 2007-05-10 18:24:13 +02:00
fw-ohci.c firewire: OHCI 1.0 Isochronous Receive support 2007-12-10 21:55:19 +01:00
fw-ohci.h firewire: fw-ohci: check for misconfigured bus (phyID == 63) 2007-10-17 00:00:08 +02:00
fw-sbp2.c firewire: fw-sbp2: fix refcounting 2007-11-07 01:59:28 +01:00
fw-topology.c firewire: in-code doc updates. 2007-10-17 00:00:09 +02:00
fw-topology.h firewire: a header cleanup 2007-10-17 00:00:09 +02:00
fw-transaction.c fix typo "insted" -> "instead" 2007-10-20 01:55:04 +02:00
fw-transaction.h firewire: fw-sbp2: set correct maximum payload (fixes CardBus adapters) 2007-08-02 20:34:16 +02:00
Kconfig firewire: point to migration document 2007-10-07 13:48:41 +02:00
Makefile firewire: prefix modules with firewire- instead of fw- 2007-05-27 23:21:01 +02:00