1. We don't need to round the SBP-2 segment size limit down to a
   multiple of 4 kB (0xffff -> 0xf000).  It is only necessary to
   ensure quadlet alignment (0xffff -> 0xfffc).

2. Use dma_set_max_seg_size() to tell the DMA mapping infrastructure
   and the block IO layer about the restriction.  This way we can
   remove the size checks and segment splitting in the queuecommand
   path.

   This assumes that no other code in the ieee1394 stack uses
   dma_map_sg() with conflicting requirements.  It furthermore assumes
   that the controller device's platform actually allows us to set the
   segment size to our liking.  Assert the latter with a BUG_ON().

3. Also use blk_queue_max_segment_size() to tell the block IO layer
   about it.  It cannot know it because our scsi_add_host() does not
   point to the FireWire controller's device.

We can also uniformly use dma_map_sg() for the single segment case just
like for the multi segment case, to further simplify the code.

Also clean up how the page table is converted to big endian.

Thanks to Grant Grundler and FUJITA Tomonori for advice.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Reported by Tino Keitel:  PL-3507 with firmware from Prolific does not
spin down the disk on START STOP UNIT with power condition = 0 and start
= 0.  It does however work with power condition = 2 or 3.

Also found while investigating this:  DViCO Momobay CX-1 and FX-3A (TI
TSB42AA9/A based) become unresponsive after START STOP UNIT with power
condition = 0 and start = 0.  They stay responsive if power condition is
set when stopping the motor.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Add the same workaround as found in fw-sbp2 for feature parity and
compatibility of the workarounds module parameter.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NJarod Wilson <jwilson@redhat.com>

This patch speeds up sbp2 a little bit --- but more importantly, it
brings the behavior of sbp2 and fw-sbp2 closer to each other.  Like
fw-sbp2, sbp2 now does not limit the size of single transfers to 255
sectors anymore, unless told so by a blacklist flag or by module load
parameters.

Only very old bridge chips have been known to need the 255 sectors
limit, and we have got one such chip in our hardwired blacklist.  There
certainly is a danger that more bridges need that limit; but I prefer to
have this issue present in both fw-sbp2 and sbp2 rather than just one of
them.

An OXUF922 with 400GB 7200RPM disk on an S400 controller is sped up by
this patch from 22.9 to 23.5 MB/s according to hdparm.  The same effect
could be achieved before by setting a higher max_sectors module
parameter.  On buses which use 1394b beta mode, sbp2 and fw-sbp2 will
now achieve virtually the same bandwidth.  Fw-sbp2 only remains faster
on 1394a buses due to fw-core's gap count optimization.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

This is upwards compatible, except that integer values other than 0 or 1
are no longer accepted.  But values like "Y", "N", "no", "nnoooh!" work
now.

Also, improve a comment on the serialize_io parameter and make the
ORB_SET_EXCLUSIVE macro ultra-safe.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

The members "dma_addr_t command_orb_dma" and "dma_addr_t sge_dma" of
sbp2.h::sbp2_command_info do not have to be aligned themselves --- only
the memory which they point to has to be.

The member "struct sbp2_command_orb command_orb" has to be aligned on
4 bytes boundary which is guaranteed because it contains u32 members.

The member "struct sbp2_unrestricted_page_table scatter_gather_element",
i.e. the SBP-2 s/g table, has to be aligned on 8 bytes boundary
according to the SBP-2 spec.  This is not a requirement for FireWire
controllers but could be expected by SBP-2 targets.

I see no need to align the members command_orb and
scatter_gather_element on CPU cacheline boundaries.  It could have
performance benefits, but on the other hand sbp2 has a somewhat wasteful
allocation scheme which should be optimized first before further tweaks
like cacheline alignments.  (E.g. don't always allocate SG_ALL s/g table
elements.)

Note, before as well as after the patch, the code relies on the
assumption that memory alignment in the virtual address space is
preserved in the physical address space after DMA mapping.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

API conversion without change in functionality
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

A signed single-bit bitfield doesn't make much sense. Make it unsigned.
Signed-off-by: NLuca Tettamanti <kronos.it@gmail.com>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

"struct scsi_id_instance_data" represents a logical unit.
Rename it to "struct sbp2_lu", and "scsi_id" to "lu".
Rename some other variables too.
Wrap almost all lines after at most 80 columns.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

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

Prepend sbp2*_ to anything globally defined in sbp2.c except for some
macros.  Strip sbp2_ from names of struct members.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

And update and reformat remaining comments.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

This work is not delayed.

Also bring the code format in a state which reduces my work to merge
pending sbp2 patchs.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Adjust parentheses, indentation, line lengths.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Remove unnecessary function prototypes.
Remove variable names from function prototypes.
Move declarations from sbp2.h to sbp2.c.
Move definitions of driver templates together near the top of sbp2.c.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Fix up for make allyesconfig.
Signed-Off-By: NDavid Howells <dhowells@redhat.com>

Scsi_remove_device() may go into uninterruptible sleep if blocked.
Therefore sbp2_remove() unblocks the Scsi_Host before the device is
requested to be removed.  But there could be another 1394 bus reset
after that which would block the host again.  The 1394 subsystem won't
call sbp2_update() concurrently to sbp2_remove(), which is why there is
no chance for sbp2_remove() to be unblocked by sbp2_update().

The fix is to tell sbp2's bus reset handler when a device is to be shut
down so that it skips scsi_block_requests() on that host.  As before,
any new commands after a reset without reconnect will be failed quickly
by sbp2scsi_queuecommand().

In the long term, means to go without scsi_block_requests() should be
found.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

If the target signals a transport failure via status block, complete the
request with DID_BUSY to indicate to the SCSI subsystem that the command
may succeed when retried.

Also log diagnostic information if the status block shows a transport
related problem.  It may point to hardware faults.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Fix for http://bugzilla.kernel.org/show_bug.cgi?id=6948

Because sbp2 writes to the target's fetch agent's registers from within
atomic context, it cannot sleep to guaranteedly get a free transaction
label.  This may repeatedly lead to "sbp2util_node_write_no_wait failed"
and consequently to SCSI command abortion after timeout.  A likely cause
is that many queue_command softirqs may occur before khpsbpkt (the
ieee1394 driver's thread which cleans up after finished transactions) is
woken up to recycle tlabels.

Sbp2 now schedules a workqueue job whenever sbp2_link_orb_command fails
in sbp2util_node_write_no_wait.  The job will reliably get a transaction
label because it can sleep.

We use the kernel-wide shared workqueue because it is unlikely that the
job itself actually needs to sleep.  In the improbable case that it has
to sleep, it doesn't need to sleep long since the standard transaction
timeout is 100ms.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

The waitqueue API is used to replace a custom wait mechanism.  Only one
global waitqueue (instead of per-device waitqueues or completions) is
added because there is usually just one waiter.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

 - Add checks for the (very unlikely) cases that the target writes too
   little or too much status data or writes unsolicited status.
 - Indicate that these and similar conditions are unlikely().
 - Check the 'resp' and 'sbp_status' fields for possible failure status.
 - Slightly optimize access macros for the status block bitfields.
 - Unify a few related log messages.

TODO:  Check if 'src'==1, then withhold the respective ORB from reuse
until status for any subsequent ORB was received.  This is an old bug
whose fix requires more complex command queue handling.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Since sbp2 is at the moment unable to do anything with the return value
of sbp2_link_orb_command, just discard it.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

The sbp2 initiator has two ways to tell a target's fetch agent about new
command ORBs:
 - Write the ORB's address to the ORB_POINTER register.  This must not
   be done while the fetch agent is active.
 - Put the ORB's address into the previously submitted ORB's next_ORB
   field and write to the DOORBELL register.  This may be done while the
   fetch agent is active or suspended.  It must not be done while the
   fetch agent is in reset state.
Sbp2 has a last_orb pointer which indicates in what way a new command
should be announced.  That pointer is concurrently accessed at various
occasions.  Furthermore, initiator and target are accessing the next_ORB
field of ORBs concurrently and asynchronously.

This patch does:
 - Protect all initiator accesses to last_orb by sbp2_command_orb_lock.
 - Add pci_dma_sync_single_for_device before a previously submitted
   ORB's next_ORB field is overwritten.
 - Insert a memory barrier between when next_ORB_lo and next_ORB_hi are
   overwritten.  Next_ORB_hi must not be updated before next_ORB_lo.
 - Remove the rather unspecific and now superfluous qualifier "volatile"
   from the next_ORB fields.
 - Add comments on how last_orb is connected with what is known about
   the target's fetch agent's state.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

It seems to have worked without the attribute during all the years
just because sizes of all struct members are multiples of 32 bits.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NBen Collins <bcollins@ubuntu.com>

This code became ineffective a few Linux releases ago and is not
required anyway.

Note from Christoph Hellwig: scsi_cmnd.request_buffer is always a
scatterlist these days.  Checking random bites into it and then
mangling the data in sbp2_check_sbp2_response will cause really bad
memory corruption when you're not lucky enough to have the check not
trigger by luck.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NBen Collins <bcollins@ubuntu.com>

In case the blacklist with workarounds for device bugs yields a false
positive, the module load parameter can now also be used as an override
instead of an addition to the blacklist.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Apple decided to copy some USB stupidity over to FireWire.

The sector number returned by iPods from read_capacity is one too many.
This may cause I/O errors, especially if the kernel is configured for EFI
partition support. We use the same workaround as usb-storage but have to
check for different model IDs.

	http://marc.theaimsgroup.com/?t=114233262300001
	https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=187409

Acknowledgements:
  Diagnosis and therapy by Mathieu Chouquet-Stringer <ml2news@free.fr>,
  additional data about affected and unaffected Apple hardware from
  Vladimir Kotal, Sander De Graaf, Bryan Olmstead and Hugh Dixon.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Grand unification of the three types of workarounds we have so far.

The "skip mode page 8" workaround is now limited to devices which
pretend to be of TYPE_DISK instead of TYPE_RBC. This workaround is no
longer enabled for Initio bridges.

Patch update in anticipation of more workarounds:
 - Add module parameter "workarounds".
 - Deprecate parameter "force_inquiry_hack".
 - Compose the blacklist of a compound type for better readability and
   extensibility.
 - Remove a now unused #define.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Let the ieee1394 core select a suitable 1394 address range for sbp2's
status FIFO instead of using a fixed range. Since the core only selects
addresses which are guaranteed to be out of the "physical range" as per
OHCI 1.1, this patch also fixes an old bug:

OHCI controllers which implement a writeable PhysicalUpperBound register
included sbp2's status FIFO in the physical range. That way sbp2 was
never notified of a succesful login and always failed after timeout.
Affected OHCI host adapters include ALi and Fujitsu controllers.

As another side effect of this patch, the status FIFO is no longer
located in a range for which OHCI chips perform "posted writes". Each
status write now requires a response subaction. But since large data
transfers involve only few status writes, there is no measurable
decrease of I/O throughput. What's more, the status FIFO is now safe
from potential host bus errors. Nevertheless, posted writes could be
re-enabled by extensions to the ARM features of the 1394 stack.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NJody McIntyre <scjody@modernduck.com>
(cherry picked from b2d38cccad4ef80d6b672b8f89aae5fe2907b113 commit)

sbp2_create_command_orb() code cleanup:
 - add two helper functions to reduce nesting depth
 - omit the return value which was always ignored
 - remove unnecessary declaration from sb2.h
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NJody McIntyre <scjody@modernduck.com>

DMA_BIDIRECTIONAL data direction may be handled properly by Linux in the
future.  For now, reject it instead to convert it to another direction.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NJody McIntyre <scjody@modernduck.com>

sbp2: various code formatting cleanups
ohci1394: remove form feed characters
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NJody McIntyre <scjody@modernduck.com>

since we no longer need to worry about it.
Depends on patch "ieee1394: remove sbp2's TYPE_RBC and 10byte handling".
Signed-off-by: NBen Collins <bcollins@debian.org>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NJody McIntyre <scjody@modernduck.com>

Added more cleanups to remove unused code.
Signed-off-by: NBen Collins <bcollins@debian.org>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NJody McIntyre <scjody@modernduck.com>

	a) TYPE_SDAD renamed to TYPE_RBC and taken to scsi.h
	b) in sbp2.c remapping of TYPE_RPB to TYPE_DISK turned off
	c) relevant places in midlayer and sd.c taught to accept TYPE_RBC
	d) sd.c::sd_read_cache_type() looks into page 6 when dealing with
TYPE_RBC - these guys have writeback cache flag there and are not guaranteed
to have page 8 at all.
	e) sd_read_cache_type() got an extra sanity check - it checks that
it got the page it asked for before using its contents.  And screams if
mismatch had happened.  Rationale: there are broken devices out there that
are "helpful" enough to go for "I don't have a page you've asked for, here,
have another one".  For example, PL3507 had been caught doing just that...
	f) sbp2 sets sdev->use_10_for_rw and sdev->use_10_for_ms instead
of bothering to remap READ6/WRITE6/MOD_SENSE, so most of the conversions
in there are gone now.

	Incidentally, I wonder if USB storage devices that have no
mode page 8 are simply RBC ones.  I haven't touched that, but it might
be interesting to check...
Signed-off-by: NAl Viro <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!