Freezing is performed atomic w.r.t. host_set->lock and once frozen
LLDD is not allowed to access the port or any qc on it.  Also, libata
makes sure that no new qc gets issued to a frozen port.

A frozen port is thawed after a reset operation completes
successfully, so reset methods must do its job while the port is
frozen.  During initialization all ports get frozen before requesting
IRQ, so reset methods are always invoked on a frozen port.

Optional ->freeze and ->thaw operations notify LLDD that the port is
being frozen and thawed, respectively.  LLDD can disable/enable
hardware interrupt in these callbacks if the controller's IRQ mask can
be changed dynamically.  If the controller doesn't allow such
operation, LLDD can check for frozen state in the interrupt handler
and ack/clear interrupts unconditionally while frozen.
Signed-off-by: NTejun Heo <htejun@gmail.com>

ata_port_schedule_eh() directly schedules EH for @ap without
associated qc.  Once EH scheduled, no further qc is allowed and EH
kicks in as soon as all currently active qc's are drained.

ata_port_abort() schedules all currently active commands for EH by
qc_completing them with ATA_QCFLAG_FAILED set.  If ata_port_abort()
doesn't find any qc to abort, it directly schedule EH using
ata_port_schedule_eh().

These two functions provide ways to invoke EH for conditions which
aren't directly related to any specfic qc.
Signed-off-by: NTejun Heo <htejun@gmail.com>

There are several ways a qc can get schedule for EH in new EH.  This
patch implements one of them - completing a qc with ATA_QCFLAG_FAILED
set or with non-zero qc->err_mask.  ALL such qc's are examined by EH.

New EH schedules a qc for EH from completion iff ->error_handler is
implemented, qc is marked as failed or qc->err_mask is non-zero and
the command is not an internal command (internal cmd is handled via
->post_internal_cmd).  The EH scheduling itself is performed by asking
SCSI midlayer to schedule EH for the specified scmd.

For drivers implementing old-EH, nothing changes.  As this change
makes ata_qc_complete() rather large, it's not inlined anymore and
__ata_qc_complete() is exported to other parts of libata for later
use.
Signed-off-by: NTejun Heo <htejun@gmail.com>

New EH framework has clear distinction about who owns a qc.  Every qc
starts owned by normal execution path - PIO, interrupt or whatever.
When an exception condition occurs which affects the qc, the qc gets
scheduled for EH.  Note that some events (say, link lost and regained,
command timeout) may schedule qc's which are not directly related but
could have been affected for EH too.  Scheduling for EH is atomic
w.r.t. ap->host_set->lock and once schedule for EH, normal execution
path is not allowed to access the qc in whatever way.  (PIO
synchronization acts a bit different and will be dealt with later)

This patch make ata_qc_from_tag() check whether a qc is active and
owned by normal path before returning it.  If conditions don't match,
NULL is returned and thus access to the qc is denied.
__ata_qc_from_tag() is the original ata_qc_from_tag() and is used by
libata core/EH layers to access inactive/failed qc's.

This change is applied only if the associated LLDD implements new EH
as indicated by non-NULL ->error_handler
Signed-off-by: NTejun Heo <htejun@gmail.com>

New EH may issue internal commands to recover from error while failed
qc's are still hanging around.  To allow such usage, reserve tag
ATA_MAX_QUEUE-1 for internal command.  This also makes it easy to tell
whether a qc is for internal command or not.  ata_tag_internal() test
implements this test.

To avoid breaking existing drivers, ata_exec_internal() uses
ATA_TAG_INTERNAL only for drivers which implement ->error_handler.
For drivers using old EH, tag 0 is used.  Note that this makes
ata_tag_internal() test valid only when ->error_handler is
implemented.  This is okay as drivers on old EH should not and does
not have any reason to use ata_tag_internal().
Signed-off-by: NTejun Heo <htejun@gmail.com>

Clear SError in ata_std_postreset().  This is to clear SError bits
which get set during reset.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Use ATA printk helpers.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Use dev->ap where possible and eliminate superflous @ap from functions
and structures.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Add dev->ap which points back to the port the device belongs to.  This
makes it unnecessary to pass @ap for silly reasons (e.g. printks).
Also, this change is necessary to accomodate later PM support which
will introduce ATA link inbetween port and device.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Use new SCR and on/offline functions.  Note that for LLDD which know
it implements SCR callbacks, SCR functions are guaranteed to succeed
and ata_port_online() == !ata_port_offline().
Signed-off-by: NTejun Heo <htejun@gmail.com>

Implement ata_scr_{valid|read|write|write_flush}() and
ata_port_{online|offline}().  These functions replace
scr_{read|write}() and sata_dev_present().

Major difference between between the new SCR functions and the old
ones is that the new ones have a way to signal error to the caller.
This makes handling SCR-available and SCR-unavailable cases in the
same path easier.  Also, it eases later PM implementation where SCR
access can fail due to various reasons.

ata_port_{online|offline}() functions return 1 only when they are
affirmitive of the condition.  e.g.  if SCR is unaccessible or
presence cannot be determined for other reasons, these functions
return 0.  So, ata_port_online() != !ata_port_offline().  This
distinction is useful in many exception handling cases.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Init ap->cbl to ATA_CBL_SATA in ata_host_init().  This is necessary
for soon-to-follow SCR handling function changes.  LLDDs are free to
change ap->cbl during probing.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Update TF image (pp->tf) only when necessary.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Add qc->result_tf and ATA_QCFLAG_RESULT_TF.  This moves the
responsibility of loading result TF from post-compltion path to qc
execution path.  qc->result_tf is loaded if explicitly requested or
the qc failsa.  This allows more efficient completion implementation
and correct handling of result TF for controllers which don't have
global TF representation such as sil3124/32.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Make ata_do_reset() deal only with reset.  postreset is now the
responsibility of the caller.  This is simpler and eases later
prereset addition.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Move ->set_mode() handlng into ata_set_mode().
Signed-off-by: NTejun Heo <htejun@gmail.com>

It's not a very good idea to allocate memory during EH.  Use
statically allocated buffer for dev->id[] and add 512byte buffer
ap->sector_buf.  This buffer is owned by EH (or probing) and to be
used as temporary buffer for various purposes (IDENTIFY, NCQ log page
10h, PM GSCR block).
Signed-off-by: NTejun Heo <htejun@gmail.com>

Hold host_set lock while finishing internal qc.
Signed-off-by: NTejun Heo <htejun@gmail.com>

ap->active_tag was cleared in ata_qc_free().  This left ap->active_tag
dangling after ata_qc_complete().  Spurious interrupts inbetween could
incorrectly access the qc.  Clear active_tag in ata_qc_complete().
This change is necessary for later EH changes.
Signed-off-by: NTejun Heo <htejun@gmail.com>

ata_bus_probe() doesn't clear dev->class after ->phy_reset().  This
can result in falsely enabled devices if probing fails.  Clear
dev->class to ATA_DEV_UNKNOWN after fetching it.
Signed-off-by: NTejun Heo <htejun@gmail.com>

While moving ata_scsi_error() from LLDD sht to libata transportt,
EXPORT_SYMBOL_GPL() entry was left out.  Kill it.
Signed-off-by: NTejun Heo <htejun@gmail.com>

AHCI calls ata_dev_classify() even when no device is attached which
results in false class code.  Fix it.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Rename ata_down_sata_spd_limit() and friends to sata_down_spd_limit()
and likewise for simplicity & consistency.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Don't directly access &qc->tf when tf == &qc->tf.
Signed-off-by: NTejun Heo <htejun@gmail.com>

libata needs to invoke EH without scmd.  This patch adds
shost->host_eh_scheduled to implement such behavior.

Currently the only user of this feature is libata and no general
interface is defined.  This patch simply adds handling for
host_eh_scheduled where needed and exports scsi_eh_wakeup() to
modules.  The rest is upto libata.  This is the result of the
following discussion.

http://thread.gmane.org/gmane.linux.scsi/23853/focus=9760

In short, SCSI host is not supposed to know about exceptions unrelated
to specific device or command.  Such exceptions should be handled by
transport layer proper.  However, the distinction is not essential to
ATA and libata is planning to depart from SCSI, so, for the time
being, libata will be using SCSI EH to handle such exceptions.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Introduce scsi_req_abort_cmd(struct scsi_cmnd *).
This function requests that SCSI Core start recovery for the
command by deleting the timer and adding the command to the eh
queue.  It can be called by either LLDDs or SCSI Core.  LLDDs who
implement their own error recovery MAY ignore the timeout event if
they generated scsi_req_abort_cmd.

First post:
http://marc.theaimsgroup.com/?l=linux-scsi&m=113833937421677&w=2Signed-off-by: NLuben Tuikov <ltuikov@yahoo.com>
Signed-off-by: NTejun Heo <htejun@gmail.com>

Adds AHCI support for the VIA VT8251.

Includes a workaround for a hardware bug which requires a Command List
Override before softreset.
Signed-off-by: NBastiaan Jacques <b.jacques@planet.nl>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Any end device that can't support any of the scanning protocols
shouldn't be scanned, so set its id to -1 to prevent
scsi_scan_target() being called for it.
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

Equivalent of the same patch for the 3w-xxxx driver.
Signed-off-by: NAdam Radford <linuxraid@amcc.com>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

scsi_kill_request() completes requests via normal SCSI completion path
which decrements busy counts; however, requests which get passed to
scsi_kill_request() aren't holding busy counts and scsi_kill_request()
don't increment them before invoking completion path resulting in
incorrect busy counts.  Bump up busy counts before invoking completion
path.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

As previously reported via Michael Reed, the FC transport took a hit
in 2.6.15 (perhaps a little earlier) when we solved a recursion error.
There are 2 deadlocks occurring:
- With scan and the delete items sharing the same workq, flushing the
  workq for the delete code was getting it stalled behind a very long
  running scan code path.
- There's a deadlock where scsi_remove_target() has to sit behind
  scsi_scan_target() due to contention over the scan_lock().

This patch resolves the 1st deadlock and significantly reduces the
odds of the second. So far, we have only replicated the 2nd deadlock
on a highly-parallel SMP system. More on the 2nd deadlock in a following
email.

This patch reworks the transport to:
- Only use the scsi host workq for scanning
- Use 2 other workq's internally. One for deletions, the other for
  scheduled deletions. Originally, we tried this with a single workq,
  but the occassional flushes of the scheduled queues was hitting the
  second deadlock with a slightly higher frequency. In the future, we'll
  look at the LLDD's and the transport to see if we can get rid of this
  extra overhead.
- When moving to the other workq's we tightened up some object states
  and some lock handling.
- Properly syncs adds/deletes
- minor code cleanups
  - directly reference fc_host_attrs, rather than through attribute
    macros
  - flush the right workq on delayed work cancel failures.

Large kudos to Michael Reed who has been working this issue for the last
month.
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

When a target is added aic79xx tries to be overly clever: it changes
the command on the fly to TEST UNIT READY and tries to requeue the
original command. Sadly this breaks SCSI compability and of course
the midlayer is getting a bit confused by it.

So we're just removing that bit of code and let the midlayer deal with
it. It's clever enough by now. And the driver code is getting simpler.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

It's no longer needed after the convrsion to use the linux srp.h file.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

As James B. correctly noted, ahd_reset_channel() in
ahd_linux_bus_reset() should be protected by ahd_lock().  However, the
main reason for not doing so was a deadlock with the interesting
polling mechanism to detect the end a bus reset.

This patch replaces the polling mechanism with a saner signalling via
flags; it also gives us the benefit of detecting any multiple calls to
ahd_reset_channel().
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

Original From: Ingo Flaschberger <if@xip.at>

To support the RA4100 array from Compaq.

This patch now correctly handles SCSI_UNKNOWN types with regard to
BLIST_REPORTLUNS2 (allow it) and cdb[1] LUN inclusion (don't).

It also allows a BLIST_MAX_512 flag to restrict the maximum transfer
length to 512 blocks (apparently this is an RA4100 problem).
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

When spinlock debugging is turned on, a struct completion grows beyond the
size allowed for the scsi_pointer.  So move the struct completion back onto
the stack.  The additional memory barriers are to keep us from completing
a random piece of kernel stack if the command happens to complete after
the error handling has finished.
Signed-off-by: NMatthew Wilcox <matthew@wil.cx>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

Bump ipr driver version to 2.1.3
Signed-off-by: NBrian King <brking@us.ibm.com>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

Encapsulate some more of the device reset processing in
preparation for SATA support.
Signed-off-by: NBrian King <brking@us.ibm.com>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

Remove some unused printk macros, make some more robust, and
convert some to use standard printk macros when possible.
Signed-off-by: NBrian King <brking@us.ibm.com>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

Simplify the dumping of the command status area by
removing some device specific information that has proven
to not be worthwhile.
Signed-off-by: NBrian King <brking@us.ibm.com>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>