On mcp55, nIEN gets stuck once set and liteon blueray rom iHOS104-08
violates ATA specification and fails to set I on D2H Reg FIS if nIEN
is set when the command was issued.  When the other party is following
the spec, both devices can work fine but when the two flaws are put
together, they can't talk to each other.

mcp55 has its own IRQ masking mechanism and there's no reason to mess
with nIEN in the first place.  Fix it by dropping nIEN diddling from
nv_mcp55_freeze/thaw().

This was originally reported by Cengiz.  Although Cengiz hasn't
verified the fix yet, I could reproduce this problem and verfiy the
fix.  Even if Cengiz is experiencing different or additional problems,
this patch is needed.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NCengiz Günay <cgunay@emory.edu>
Cc: stable@kernel.org
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Separate out ata_pci_bmdma_prepare_host() and ata_pci_bmdma_init_one()
from their SFF counterparts.  SFF ones no longer try to initialize
BMDMA or set PCI master.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Separate out BMDMA irq handler from SFF irq handler.  The misnamed
host_intr() functions are renamed to ata_sff_port_intr() and
ata_bmdma_port_intr().  Common parts are factored into
__ata_sff_port_intr() and __ata_sff_interrupt() and used by sff and
bmdma interrupt routines.

All BMDMA drivers now use ata_bmdma_interrupt() or
ata_bmdma_port_intr() while all non-BMDMA SFF ones use
ata_sff_interrupt() or ata_sff_port_intr().

For now, ata_pci_sff_init_one() uses ata_bmdma_interrupt() as it's
used by both SFF and BMDMA drivers.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

ata_sff_irq_clear() is BMDMA specific.  Rename it to
ata_bmdma_irq_clear(), move it to ata_bmdma_port_ops and make
->sff_irq_clear() optional.

Note: ata_bmdma_irq_clear() is actually only needed by ata_piix and
      possibly by sata_sil.  This should be moved to respective low
      level drivers later.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Separate out ata_bmdma_qc_issue() from ata_sff_qc_issue() such that
ata_sff_qc_issue() only deals with non-BMDMA SFF protocols (PIO and
nodata) while ata_bmdma_qc_issue() deals with the BMDMA protocols and
uses ata_sff_qc_issue() for non-DMA commands.  All the users are
updated accordingly.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

struct ata_prd and ap->prd are BMDMA specific.  Add bmdma_ prefix to
them and move them inside CONFIG_ATA_SFF.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Both qc_prep functions deal only with BMDMA PRD setup and PIO only SFF
drivers don't need them.  Rename to ata_bmdma_[dumb_]qc_prep() and
relocate.

All usages are renamed except for pdc_adma and sata_qstor.  Those two
drivers are not BMDMA drivers and don't need to call BMDMA qc_prep
functions.  Calls to ata_sff_qc_prep() in the two drivers are removed.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Some of error handling logic in ata_sff_error_handler() and all of
ata_sff_post_internal_cmd() are for BMDMA.  Create
ata_bmdma_error_handler() and ata_bmdma_post_internal_cmd() and move
BMDMA part into those.

While at it, change DMA protocol check to ata_is_dma(), fix
post_internal_cmd to call ap->ops->bmdma_stop instead of directly
calling ata_bmdma_stop() and open code hardreset selection so that
ata_std_error_handler() doesn't have to know about sff hardreset.

As these two functions are BMDMA specific, there's no reason to check
for bmdma_addr before calling bmdma methods if the protocol of the
failed command is DMA.  sata_mv and pata_mpc52xx now don't need to set
.post_internal_cmd to ATA_OP_NULL and pata_icside and sata_qstor don't
need to set it to their bmdma_stop routines.

ata_sff_post_internal_cmd() becomes noop and is removed.

This fixes p3 described in clean-up-BMDMA-initialization patch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

When BMDMA initialization failed or BMDMA was not available for
whatever reason, bmdma_addr was left at zero and used as an indication
that BMDMA shouldn't be used.  This leads to the following problems.

p1. For BMDMA drivers which don't use traditional BMDMA register,
    ata_bmdma_mode_filter() incorrectly inhibits DMA modes.  Those
    drivers either have to inherit from ata_sff_port_ops or clear
    ->mode_filter explicitly.

p2. non-BMDMA drivers call into BMDMA PRD table allocation.  It
    doesn't actually allocate PRD table if bmdma_addr is not
    initialized but is still confusing.

p3. For BMDMA drivers which don't use traditional BMDMA register, some
    methods might not be invoked as expected (e.g. bmdma_stop from
    ata_sff_post_internal_cmd()).

p4. SFF drivers w/ custom DMA interface implement noop BMDMA ops
    worrying libata core might call into one of them.

These problems are caused by the muddy line between SFF and BMDMA and
the assumption that all BMDMA controllers initialize bmdma_addr.

This patch fixes p1 and p2 by removing the bmdma_addr assumption and
moving prd allocation to BMDMA port start.  Later patches will fix the
remaining issues.

This patch improves BMDMA initialization such that

* When BMDMA register initialization fails, falls back to PIO instead
  of failing.  ata_pci_bmdma_init() never fails now.

* When ata_pci_bmdma_init() falls back to PIO, it clears
  ap->mwdma_mask and udma_mask instead of depending on
  ata_bmdma_mode_filter().  This makes ata_bmdma_mode_filter()
  unnecessary thus resolving p1.

* ata_port_start() which actually is BMDMA specific is moved to
  ata_bmdma_port_start().  ata_port_start() and ata_sff_port_start()
  are killed.

* ata_sff_port_start32() is moved and renamed to
  ata_bmdma_port_start32().

Drivers which no longer call into PRD table allocation are...

  pdc_adma, sata_inic162x, sata_qstor, sata_sx4, pata_cmd640 and all
  drivers which inherit from ata_sff_port_ops.

pata_icside sets ->port_start to ATA_OP_NULL as it doesn't need PRD
but is a BMDMA controller and doesn't have custom port_start like
other such controllers.

Note that with the previous patch which makes all and only BMDMA
drivers inherit from ata_bmdma_port_ops, this change doesn't break
drivers which need PRD table.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

ATA_FLAG_DISABLED is only used by drivers which don't use
->error_handler framework and is largely broken.  Its only meaningful
function is to make irq handlers skip processing if the flag is set,
which is largely useless and even harmful as it makes those ports more
likely to cause IRQ storms.

Kill ATA_FLAG_DISABLED and makes the callers disable attached devices
instead.  ata_port_probe() and ata_port_disable() which manipulate the
flag are also killed.

This simplifies condition check in IRQ handlers.  While updating IRQ
handlers, remove ap NULL check as libata guarantees consecutive port
allocation (unoccupied ports are initialized with dummies) and
long-obsolete ATA_QCFLAG_ACTIVE check (checked by ata_qc_from_tag()).
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

sata_nv was incorrectly using ata_host_activate() instead of
ata_pci_sff_activate_host() leading to IRQ assignment failure in
legacy mode.  Fix it.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Robert Hancock <hancockr@shaw.ca>
Cc: stable@kernel.org
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

Except for SCSI no device drivers distinguish between physical and
hardware segment limits.  Consolidate the two into a single segment
limit.
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

This patch modifies scsi_host_template->change_queue_depth so that
it takes an argument indicating why it is being called. This will be
used so that if a LLD needs to do some extra processing when
handling queue fulls or later ramp ups, it can do so.

This is a simple port of the drivers setting a change_queue_depth
callback. In the patch I just have these LLDs adjust the queue depth
if the user was requesting it.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>

[Vasu.Dev: v2
	Also converted pmcraid_change_queue_depth and then verified
all modules compile  using "make allmodconfig" for any new build
warnings on X86_64.

	Updated original description after combing two original
patches from Mike to make this patch git bisectable.]
Signed-off-by: NVasu Dev <vasu.dev@intel.com>
[jejb: fixed up 53c700]
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>

prereset doesn't bring link online if hardreset is about to happen and
nv_hardreset() may skip if conditions are not right so softreset may
be entered with non-working link status if the system firmware didn't
bring it up before entering OS code which can happen during resume.
This patch makes nv_hardreset() to bring up the link if it's skipping
reset.

This bug was reported by frodone@gmail.com in the following bug entry.

  http://bugzilla.kernel.org/show_bug.cgi?id=14329Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: frodone@gmail.com
Cc: stable@kernel.org
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

At least the nVidia MCP55 controller quite happily supports MSI.
This adds an option to use it. It is disabled by default.
As per feedback by Robert Hancock, it will honour the user
request as the kernel will not enable MSI where the controller
or the specific system configuration do not support it.
Signed-off-by: NTony Vroon <tony@linx.net>
Cc: Robert Hancock <hancockrwd@gmail.com>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

When I thought it was finally defeated, it came back with vengeance.
The failure cases are ever more convoluted.  Now there is a single
combination which fails boot probing - MCP5x + Intel SSD and there are
two hotplug failure reports on different flavors where softreset fails
to bring up the device.

Through the many bug reports after the switch to hardreset, the
following patterns emerged.

- Softreset during boot always works.

- Hardreset during boot sometimes fails to bring up the link on
  certain comibnations and device signature acquisition is unreliable.

- Hardreset is often necessary after hotplug.

It looks like the old behavior of preferring softreset was somehow
pretty close to the working reset protocol although it could have lost
a device during phy error handling by issuing hardreset.

This patch implements nv_hardreset() which kicks in only for post-boot
(!LOADING) device probing resets.  This should be able to work around
all known problem cases.  This isn't perfect but given the various
hardreset quirks on these controllers, I think this is as good as it
can get.

Tested on mcp5x (swncq), nf3 and ck804 for all both boot, warm and
hot probing cases.

Kudos to all the bug reporters and their painful hours with these damn
controllers.  ;-)
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Robert Hancock <hancockr@shaw.ca>
Reported-by: NDavid Lang <david@lang.hm>
Reported-by: NSamo Vodopivec <lament.email.si@gmail.com>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

On a timeout call a device specific handler early in the recovery so that
we can complete and process successful commands which timed out due to IRQ
loss or the like rather more elegantly.

[Revised to exclude the timeout handling on a few devices that inherit from
 SFF but are not SFF enough to use the default timeout handler]
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

No functional changes in this patch.
Signed-off-by: NErik Inge Bolsø <knan-lkml@anduin.net>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Update MODULE_PARM_DESC for ADMA to reflect the fact that the
option is disabled by default.
Signed-off-by: NBrandon Ehle <azverkan@yahoo.com>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Kernel bz#12176 reports that nf2 hardreset simply doesn't work.  Give
up.  Argh...
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Robert Hancock <hancockr@shaw.ca>
Reported-by: NSaro <saro_v@hotmail.it>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

While playing with nvraid, I found out that rmmoding and insmoding
often trigger hardreset failure on the first port (the second one was
always okay).  Seriously, how diverse can you get with hardreset
behaviors?  Anyways, make ck804 use noclassify variant too.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

MCP5x family of controllers seem to share much more with nf2's as far
as reset protocol is concerned.  It requires heardreset to get the PHY
going and classfication code report after hardreset is unreliable.
Create a new board type MCP5x and use noclassify hardreset.  SWNCQ is
modified to inherit from this new type.

This fixes hotplug regression reported in kernel bz#12351.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

nv_nf2_hardreset() will be used by other flavors too.  Rename it to
nv_noclassify_hardreset().
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

All three flavors of sata_nv's are different in how their hardreset
behaves.

* generic: Hardreset is not reliable.  Link often doesn't come online
  after hardreset.

* nf2/3: A little bit better - link comes online with longer debounce
  timing.  However, nf2/3 can't reliable wait for the first D2H
  Register FIS, so it can't wait for device readiness or classify the
  device after hardreset.  Follow-up SRST required.

* ck804: Hardreset finally works.

The core layer change to prefer hardreset and follow up changes
exposed the above issues and caused various detection regressions for
all three flavors.  This patch, hopefully, fixes all the known issues
and should make sata_nv error handling more reliable.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Logically, SCR access ops should take @link; however, there was no
compelling reason to convert all SCR access ops when adding @link
abstraction as there's one-to-one mapping between a port and a non-PMP
link.  However, that assumption won't hold anymore with the scheduled
addition of slave link.

Make SCR access ops per-link.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Commit 2fd673ec which tried to remove
hardreset for generic accidentally removed it for all flavors as all
others were inheriting from nv_generic_ops.  This patch reinstates
nv_hardreset() and puts it into nv_common_ops which all flavors
inherit from.  nv_generic_ops now inherits from nv_common_ops and
overrides .hardreset to ATA_OP_NULL.

While at it, explain why nv_hardreset and ATA_OP_NULL override are
necessary.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

of them being unifying probing, hotplug and EH reset paths uniform.
Previously, broken hardreset could go unnoticed as it wasn't used
during probing but when something goes wrong or after hotplug the
problem will surface and bite hard.

OSDL bug 11195 reports that sata_nv generic flavor falls into this
category.  Hardreset itself succeeds but PHY stays offline after
hardreset.  I tried longer debounce timing but the result was the
same.

  http://bugzilla.kernel.org/show_bug.cgi?id=11195

So, it seems we'll have to drop hardreset from the generic flavor.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Peer Chen <pchen@nvidia.com>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

sata_nv hardreset can't classify but was left out while unifying
follow-up SRST request mechanism[1].  This caused detection failures
on those controllers.  Fix it.

Reported and bisected by Roland Dreier, Petr Vandrovec and Marc
Dionne.  Thanks guys.

[1] 305d2a1aSigned-off-by: NTejun Heo <htejun@gmail.com>
Cc: Roland Dreier <rdreier@cisco.com>
Cc: Petr Vandrovec <vandrove@vc.cvut.cz>
Cc: Marc Dionne <marc.c.dionne@gmail.com>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Add sff_ prefix to SFF specific port ops.

This rename is in preparation of separating SFF support out of libata
core layer.  This patch strictly renames ops and doesn't introduce any
behavior difference.
Signed-off-by: NTejun Heo <htejun@gmail.com>

SFF functions have confusing names.  Some have sff prefix, some have
bmdma, some std, some pci and some none.  Unify the naming by...

* SFF functions which are common to both BMDMA and non-BMDMA are
  prefixed with ata_sff_.

* SFF functions which are specific to BMDMA are prefixed with
  ata_bmdma_.

* SFF functions which are specific to PCI but apply to both BMDMA and
  non-BMDMA are prefixed with ata_pci_sff_.

* SFF functions which are specific to PCI and BMDMA are prefixed with
  ata_pci_bmdma_.

* Drop generic prefixes from LLD specific routines.  For example,
  bfin_std_dev_select -> bfin_dev_select.

The following renames are noteworthy.

  ata_qc_issue_prot() -> ata_sff_qc_issue()
  ata_pci_default_filter() -> ata_bmdma_mode_filter()
  ata_dev_try_classify() -> ata_sff_dev_classify()

This rename is in preparation of separating SFF support out of libata
core layer.  This patch strictly renames functions and doesn't
introduce any behavior difference.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Continues to have open issues, and engineering support is extremely difficult
to come by, according to fellow NVIDIA engineers.
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Signed-off-by: NZoltan Boszormenyi <zboszor@dunaweb.hu>
Cc: Robert Hancock <hancockr@shaw.ca>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Currently reset methods are not specified directly in the
ata_port_operations table.  If a LLD wants to use custom reset
methods, it should construct and use a error_handler which uses those
reset methods.  It's done this way for two reasons.

First, the ops table already contained too many methods and adding
four more of them would noticeably increase the amount of necessary
boilerplate code all over low level drivers.

Second, as ->error_handler uses those reset methods, it can get
confusing.  ie. By overriding ->error_handler, those reset ops can be
made useless making layering a bit hazy.

Now that ops table uses inheritance, the first problem doesn't exist
anymore.  The second isn't completely solved but is relieved by
providing default values - most drivers can just override what it has
implemented and don't have to concern itself about higher level
callbacks.  In fact, there currently is no driver which actually
modifies error handling behavior.  Drivers which override
->error_handler just wraps the standard error handler only to prepare
the controller for EH.  I don't think making ops layering strict has
any noticeable benefit.

This patch makes ->prereset, ->softreset, ->hardreset, ->postreset and
their PMP counterparts propoer ops.  Default ops are provided in the
base ops tables and drivers are converted to override individual reset
methods instead of creating custom error_handler.

* ata_std_error_handler() doesn't use sata_std_hardreset() if SCRs
  aren't accessible.  sata_promise doesn't need to use separate
  error_handlers for PATA and SATA anymore.

* softreset is broken for sata_inic162x and sata_sx4.  As libata now
  always prefers hardreset, this doesn't really matter but the ops are
  forced to NULL using ATA_OP_NULL for documentation purpose.

* pata_hpt374 needs to use different prereset for the first and second
  PCI functions.  This used to be done by branching from
  hpt374_error_handler().  The proper way to do this is to use
  separate ops and port_info tables for each function.  Converted.
Signed-off-by: NTejun Heo <htejun@gmail.com>

libata core layer doesn't care about sht or ->irq_handler.  Those are
only of interest to the LLD during initialization.  This is confusing
and has caused several drivers to have duplicate unused initializers
for these fields.

Currently only sata_nv uses these fields.  Make sata_nv use
->private_data, which is supposed to carry LLD-specific information,
instead and kill ->sht and ->irq_handler.  nv_pi_priv structure is
defined and struct literals are used to initialize private_data.
Notational overhead is negligible.
Signed-off-by: NTejun Heo <htejun@gmail.com>

libata lets low level drivers build ata_port_operations table and
register it with libata core layer.  This allows low level drivers
high level of flexibility but also burdens them with lots of
boilerplate entries.

This becomes worse for drivers which support related similar
controllers which differ slightly.  They share most of the operations
except for a few.  However, the driver still needs to list all
operations for each variant.  This results in large number of
duplicate entries, which is not only inefficient but also error-prone
as it becomes very difficult to tell what the actual differences are.

This duplicate boilerplates all over the low level drivers also make
updating the core layer exteremely difficult and error-prone.  When
compounded with multi-branched development model, it ends up
accumulating inconsistencies over time.  Some of those inconsistencies
cause immediate problems and fixed.  Others just remain there dormant
making maintenance increasingly difficult.

To rectify the problem, this patch implements ata_port_operations
inheritance.  To allow LLDs to easily re-use their own ops tables
overriding only specific methods, this patch implements poor man's
class inheritance.  An ops table has ->inherits field which can be set
to any ops table as long as it doesn't create a loop.  When the host
is started, the inheritance chain is followed and any operation which
isn't specified is taken from the nearest ancestor which has it
specified.  This operation is called finalization and done only once
per an ops table and the LLD doesn't have to do anything special about
it other than making the ops table non-const such that libata can
update it.

libata provides four base ops tables lower drivers can inherit from -
base, sata, pmp, sff and bmdma.  To avoid overriding these ops
accidentaly, these ops are declared const and LLDs should always
inherit these instead of using them directly.

After finalization, all the ops table are identical before and after
the patch except for setting .irq_handler to ata_interrupt in drivers
which didn't use to.  The .irq_handler doesn't have any actual effect
and the field will soon be removed by later patch.

* sata_sx4 is still using old style EH and currently doesn't take
  advantage of ops inheritance.
Signed-off-by: NTejun Heo <htejun@gmail.com>

libata lets low level drivers build scsi_host_template and register it
to the SCSI layer.  This allows low level drivers high level of
flexibility but also burdens them with lots of boilerplate entries.

This patch implements SHT initializers which can be used to initialize
all the boilerplate entries in a sht.  Three variants of them are
implemented - BASE, BMDMA and NCQ - for different types of drivers.
Note that entries can be overriden by putting individual initializers
after the helper macro.

All sht tables are identical before and after this patch.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Over the time, port info, ops and sht structures developed quite a bit
of inconsistencies.  This patch updates drivers.

* Enable/disable_pm callbacks added to all ahci ops tables.

* Every driver for SFF controllers now uses ata_sff_port_start()
  instead of ata_port_start() unless the driver has custom
  implementation.

* Every driver for SFF controllers now uses ata_pci_default_filter()
  unless the driver has custom implementation.

* Removed an odd port_info->sht initialization from ata_piix.c.
  Likely a merge byproduct.

* A port which has ATA_FLAG_SATA set doesn't need to set cable_detect
  to ata_cable_sata().  Remove it from via and mv port ops.

* Some drivers had unnecessary .max_sectors initialization which is
  ignored and was missing .slave_destroy callback.  Fixed.

* Removed unnecessary sht initializations port_info's.

* Removed onsolete scsi device suspend/resume callbacks from
  pata_bf54x.

* No reason to set ata_pci_default_filter() and bmdma functions for
  PIO-only drivers.  Remove those callbacks and replace
  ata_bmdma_irq_clear with ata_noop_irq_clear.

* pata_platform sets port_start to ata_dummy_ret0.  port_start can
  just be set to NULL.

* sata_fsl supports NCQ but was missing qc_defer.  Fixed.

* pata_rb600_cf implements dummy port_start.  Removed.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Now that hardreset is the preferred method of resetting, there's no
need for ATA_LFLAG_HRST_TO_RESUME flag.  Kill it.
Signed-off-by: NTejun Heo <htejun@gmail.com>

When both soft and hard resets are available, libata preferred
softreset till now.  The logic behind it was to be softer to devices;
however, this doesn't really help much.  Rationales for the change:

* BIOS may freeze lock certain things during boot and softreset can't
  unlock those.  This by itself is okay but during operation PHY event
  or other error conditions can trigger hardreset and the device may
  end up with different configuration.

  For example, after a hardreset, previously unlockable HPA can be
  unlocked resulting in different device size and thus revalidation
  failure.  Similar condition can occur during or after resume.

* Certain ATAPI devices require hardreset to recover after certain
  error conditions.  On PATA, this is done by issuing the DEVICE RESET
  command.  On SATA, COMRESET has equivalent effect.  The problem is
  that DEVICE RESET needs its own execution protocol.

  For SFF controllers with bare TF access, it can be easily
  implemented but more advanced controllers (e.g. ahci and sata_sil24)
  require specialized implementations.  Simply using hardreset solves
  the problem nicely.

* COMRESET initialization sequence is the norm in SATA land and many
  SATA devices don't work properly if only SRST is used.  For example,
  some PMPs behave this way and libata works around by always issuing
  hardreset if the host supports PMP.

  Like the above example, libata has developed a number of mechanisms
  aiming to promote softreset to hardreset if softreset is not going
  to work.  This approach is time consuming and error prone.

  Also, note that, dependingon how you read the specs, it could be
  argued that PMP fan-out ports require COMRESET to start operation.
  In fact, all the PMPs on the market except one don't work properly
  if COMRESET is not issued to fan-out ports after PMP reset.

* COMRESET is an integral part of SATA connection and any working
  device should be able to handle COMRESET properly.  After all, it's
  the way to signal hardreset during reboot.  This is the most used
  and recommended (at least by the ahci spec) method of resetting
  devices.

So, this patch makes libata prefer hardreset over softreset by making
the following changes.

* Rename ATA_EH_RESET_MASK to ATA_EH_RESET and use it whereever
  ATA_EH_{SOFT|HARD}RESET used to be used.  ATA_EH_{SOFT|HARD}RESET is
  now only used to tell prereset whether soft or hard reset will be
  issued.

* Strip out now unneeded promote-to-hardreset logics from
  ata_eh_reset(), ata_std_prereset(), sata_pmp_std_prereset() and
  other places.
Signed-off-by: NTejun Heo <htejun@gmail.com>