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>
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>
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>
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>
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: FUJITA 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Drop filenames from file preamble, drop editor annotations and
use standard indent style for block comments.
Signed-off-by: Kristian 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: Kristian Høgsberg <krh@redhat.com>
Signed-off-by: Stefan 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: Kristian Høgsberg <krh@redhat.com>
Signed-off-by: Stefan 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: Kristian Høgsberg <krh@redhat.com>
Signed-off-by: Stefan 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: Kristian Høgsberg <krh@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
