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: NStefan Richter <stefanr@s5r6.in-berlin.de>
Tested-by: NDavid Moore <dcm@acm.org>

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: NStefan Richter <stefanr@s5r6.in-berlin.de>

type
    function_name(parameters);

is nice to look at but was not used consistently.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

"ret" is the new "retval".
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Add per-device dma_mapping_ops support for CONFIG_X86_64 as POWER
architecture does:

This enables us to cleanly fix the Calgary IOMMU issue that some devices
are not behind the IOMMU (http://lkml.org/lkml/2008/5/8/423).

I think that per-device dma_mapping_ops support would be also helpful for
KVM people to support PCI passthrough but Andi thinks that this makes it
difficult to support the PCI passthrough (see the above thread).  So I
CC'ed this to KVM camp.  Comments are appreciated.

A pointer to dma_mapping_ops to struct dev_archdata is added.  If the
pointer is non NULL, DMA operations in asm/dma-mapping.h use it.  If it's
NULL, the system-wide dma_ops pointer is used as before.

If it's useful for KVM people, I plan to implement a mechanism to register
a hook called when a new pci (or dma capable) device is created (it works
with hot plugging).  It enables IOMMUs to set up an appropriate
dma_mapping_ops per device.

The major obstacle is that dma_mapping_error doesn't take a pointer to the
device unlike other DMA operations.  So x86 can't have dma_mapping_ops per
device.  Note all the POWER IOMMUs use the same dma_mapping_error function
so this is not a problem for POWER but x86 IOMMUs use different
dma_mapping_error functions.

The first patch adds the device argument to dma_mapping_error.  The patch
is trivial but large since it touches lots of drivers and dma-mapping.h in
all the architecture.

This patch:

dma_mapping_error() doesn't take a pointer to the device unlike other DMA
operations.  So we can't have dma_mapping_ops per device.

Note that POWER already has dma_mapping_ops per device but all the POWER
IOMMUs use the same dma_mapping_error function.  x86 IOMMUs use device
argument.

[akpm@linux-foundation.org: fix sge]
[akpm@linux-foundation.org: fix svc_rdma]
[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: fix bnx2x]
[akpm@linux-foundation.org: fix s2io]
[akpm@linux-foundation.org: fix pasemi_mac]
[akpm@linux-foundation.org: fix sdhci]
[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: fix sparc]
[akpm@linux-foundation.org: fix ibmvscsi]
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Muli Ben-Yehuda <muli@il.ibm.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Avi Kivity <avi@qumranet.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch contains the following cleanups:
- #if 0 the following unused structs:
  - fw-transaction.c:fw_low_memory_region
  - fw-transaction.c:fw_private_region
  - fw-transaction.c:fw_csr_region
  - fw-transaction.c:fw_unit_space_region
- remove the following unused EXPORT_SYMBOL's:
  - fw-card.c:fw_core_add_descriptor
  - fw-card.c:fw_core_remove_descriptor
  - fw-iso.c:fw_iso_context_create
  - fw-iso.c:fw_iso_context_destroy
  - fw-iso.c:fw_iso_context_start
  - fw-iso.c:fw_iso_context_queue
  - fw-iso.c:fw_iso_context_stop
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Drop filenames from file preamble, drop editor annotations and
use standard indent style for block comments.
Signed-off-by: NKristian Hoegsberg <krh@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> (fixed typo)

Setting these at create_context time or start_iso time doesn't matter
much, but raw1394 sets them at start_iso time so that will be easier to
emulate this way.
Signed-off-by: NKristian Høgsberg <krh@redhat.com>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Remove space before tab and trailing whitespace.
Unify indentation of goto target labels.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Signed-off-by: NKristian Høgsberg <krh@redhat.com>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

We need the channel number as we queue up iso packets for transmission
so we can fill out the header correctly.
Signed-off-by: NKristian Høgsberg <krh@redhat.com>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Signed-off-by: NKristian Høgsberg <krh@redhat.com>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

When the DMA is setup to not strip any headers, we need to use
the buffer fill descriptor instead of the dual buffer, since the
dual buffer descriptor must strip a non-zero number of header quadlets.
Signed-off-by: NKristian Høgsberg <krh@redhat.com>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Signed-off-by: NKristian Høgsberg <krh@redhat.com>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Signed-off-by: NKristian Høgsberg <krh@redhat.com>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Signed-off-by: NKristian Høgsberg <krh@redhat.com>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

This patch splits out the iso buffer so we can initialize it at mmap
time with the size provided in the mmap call.  Furthermore, allocate
the backing pages using alloc_page to avoid setting up kernel side
virtual memory mappings for the pages.
Signed-off-by: NKristian Høgsberg <krh@redhat.com>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Pointed out by Pete Zaitcev.
Signed-off-by: NKristian Høgsberg <krh@redhat.com>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NKristian Høgsberg <krh@redhat.com>

Signed-off-by: NKristian Høgsberg <krh@redhat.com>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Signed-off-by: NKristian Høgsberg <krh@redhat.com>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>