Convert ->scr_read/write callbacks to return error code to better
indicate failure.  This will help handling of SCR_NOTIFICATION.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

When an NCQ command fails, all commands in flight are aborted and the
offending one is reported using log page 10h.  Depending on controller
characteristics and LLD implementation, all commands may appear as
having a device error due to shared TF status making it hard to
determine what's actually going on.

This patch adds AC_ERR_NCQ, marks the command reported by log page 10h
with it and print extra "<F>" after the error report for the command
to help distinguishing the offending command.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Requiring LLDs to format multiple error description messages properly
doesn't work too well.  Help LLDs a bit by making ata_ehi_push_desc()
insert ", " on each invocation.  __ata_ehi_push_desc() is the raw
version without the automatic separator.

While at it, make ehi_desc interface proper functions instead of
macros.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Add @is_cmd to ata_tf_to_fis().  This controls bit 7 of the second
byte which tells the device whether this H2D FIS is for a command or
not.  This cleans up ahci a bit and will be used by PMP.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Horkage handling had the following problems.

* dev->horkage was positioned after ATA_DEVICE_CLEAR_OFFSET, so it was
  cleared before the device is configured.  This broke
  HORKAGE_DIAGNOSTIC.

* Some used dev->horkage while others called ata_device_blacklisted()
  directly.  This was at best confusing.

This patch moves dev->horkage right after dev->flags and set the field
according to the blacklist during device configuration.  All users
test against dev->horkage.  ata_device_blacklisted() now has only one
user, make it static.  While at it, rename it to ata_dev_blacklisted()
for consistency.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

With PCI resource fix up for legacy hosts.  We can use the same code
path to allocate IO resources and initialize host for both legacy and
native SFF hosts.  Only IRQ requesting needs to be different.

Rename ata_pci_*_native_host() to ata_pci_*_sff_host(), kill all
legacy specific functions and use the renamed functions instead.  This
simplifies code a lot.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

We should not use cancel_work_sync(delayed_work->work). This works, but not
good. We can use cancel_rearming_delayed_work(), this also simplifies the
code.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Add ata_dumb_qc_prep and supporting logic so that a driver can just
specify it needs to be helped in this area. 64K entries are split
as with drivers/ide.
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Implement _GTM/_STM support.  acpi_gtm is added to ata_port which
stores _GTM parameters over suspend/resume cycle.  A new hook
ata_acpi_on_suspend() is responsible for storing _GTM parameters
during suspend.  _STM is executed in ata_acpi_on_resume().  With this
change, invoking _GTF is safe on IDE hierarchy and acpi_sata check
before _GTF is removed.

ata_acpi_gtm() and ata_acpi_stm() implementation is taken from Alan
Cox's pata_acpi implementation.  ata_acpi_gtm() is fixed such that the
result parameter is not shifted by sizeof(union acpi_object).
Signed-off-by: NTejun Heo <htejun@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

This patch reimplements ACPI invocation such that, instead of
exporting ACPI details to the rest of libata, ACPI event handlers -
ata_acpi_on_resume() and ata_acpi_on_devcfg() - are used.  These two
functions are responsible for determining whether specific ACPI method
is used and when.

On resume, _GTF is scheduled by setting ATA_DFLAG_ACPI_PENDING device
flag.  This is done this way to avoid performing the action on wrong
device device (device swapping while suspended).

On every ata_dev_configure(), ata_acpi_on_devcfg() is called, which
performs _SDD and _GTF.  _GTF is performed only after resuming and, if
SATA, hardreset as the ACPI spec specifies.  As _GTF may contain
arbitrary commands, IDENTIFY page is re-read after _GTF taskfiles are
executed.

If one of ACPI methods fails, ata_acpi_on_devcfg() retries on the
first failure.  If it fails again on the second try, ACPI is disabled
on the device.  Note that successful configuration clears ACPI failed
status.

With all feature checks moved to the above two functions,
do_drive_set_taskfiles() is trivial and thus collapsed into
ata_acpi_exec_tfs(), which is now static and converted to return the
number of executed taskfiles to be used by ata_acpi_on_resume().  As
failures are handled properly, ata_acpi_push_id() now returns -errno
on errors instead of unconditional zero.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

* Add acpi_handle to ata_host and ata_port.  Rename
  ata_device->obj_handle to ->acpi_handle and move it above such that
  it doesn't get cleared on reconfiguration.

* Replace ACPI node association which ata_acpi_associate() which is
  called once during host initialization.  Unlike the previous
  implementation, ata_acpi_associate() uses ATA_FLAG_ACPI_SATA to
  choose between IDE or SATA ACPI hierarchy and uses simple child look
  up instead of recursive walk to match the nodes.  This is way safer
  and simpler.  Please read the following message for more info.

  http://article.gmane.org/gmane.linux.ide/17554Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

ATA_HORKAGE_DMA_RW_ONLY for TORiSAN is verified to be subset of using
DMA for ATAPI commands which aren't aligned to 16 bytes.  As libata
now doesn't use DMA for unaligned ATAPI commands, the horkage is
redundant.  Kill it.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

The infamous abnormal status message triggers on not so abnormal cases
including empty port and even when it's being triggered on actual
errors the info it provides is redundant and out of context - higher
level functions will print the info in better safe later anyway.

Also, by being triggered all the time, it leads people to think that
the abnormality is somehow related to all ATA and system problems
they're experiencing and gives owners of healthy systems unfounded
doubts about the integrity of the universe.  Make it a DPRINTK and
save the universe.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

The ata IRQ ack functions are only used when debugging. Unfortunately
almost every controller that calls them can cause crashes in some
configurations as there are missing checks for bmdma presence.

In addition ata_port_start insists of installing DMA buffers and pad
buffers for controllers regardless. The SFF controllers actually need to
make that decision dynamically at controller setup time and all need the
same helper - so we add ata_sff_port_start. Future patches will switch
the SFF drivers to use this.
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Several people have reported LITE-ON LTR-48246S detection failed
because SETXFER fails.  It seems the device raises IRQ too early after
SETXFER.  This is controller independent.  The same problem has been
reported for different controllers.

So, now we have pata_via where the controller raises IRQ before it's
ready after SETXFER and a device which does similar thing.  This patch
makes libata always execute SETXFER via polling.  As this only happens
during EH, performance impact is nil.  Setting ATA_TFLAG_POLLING is
also moved from issue hot path to ata_dev_set_xfermode() - the only
place where SETXFER can be issued.

Note that ATA_TFLAG_POLLING applies only to drivers which implement
SFF TF interface and use libata HSM.  More advanced controllers ignore
the flag.  This doesn't matter for this fix as SFF TF controllers are
the problematic ones.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

As of the -mm tree we don't have post_set_mode users any more.
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Our assumption that most distros issue STANDBYNOW seems wrong.  The
upstream sysvinit and thus many distros including gentoo and opensuse
don't take any action for libata disks on spindown.  We can skip
compat handling for these distros so that they don't need to update
anything to take advantage of kernel-side shutdown.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Whether a controller needs IDE or SATA ACPI hierarchy is determined by
the programming interface of the controller not by whether the
controller is SATA or PATA, or it supports slave device or not.  This
patch adds ATA_FLAG_ACPI_SATA port flags which tells libata-acpi that
the port needs SATA ACPI nodes, and sets the flag for ahci and
sata_sil24.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Device might be resized during ata_dev_configure() due to HPA or
(later) ACPI _GTF.  Currently it's worked around by caching n_sectors
before turning off HPA.  The cached original size is overwritten if
the device is reconfigured without being hardreset - which always
happens after configuring trasnfer mode.  If the device gets hardreset
for some reason after that, revalidation fails with -ENODEV.

This patch makes size checking more robust by moving n_sectors check
from ata_dev_reread_id() to ata_dev_revalidate() after the device is
fully configured.  No matter what happens during configuration, a
device must have the same n_sectors after fully configured to be
treated as the same device.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

ACPI applies to both SATA and PATA.  Drop the 'S' from the config
variable.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

libata enables SCSI host during ATA host activation which happens
after IRQ handler is registered and IRQ is enabled.  All ATA ports are
in frozen state when IRQ is enabled but frozen ports may raise limited
number of IRQs after being frozen - IOW, ->freeze() is not responsible
for clearing pending IRQs.  During normal operation, the IRQ handler
is responsible for clearing spurious IRQs on frozen ports and it
usually doesn't require any extra code.

Unfortunately, during host initialization, the IRQ handler can end up
scheduling EH for a port whose SCSI host isn't initialized yet.  This
results in OOPS in the SCSI midlayer.  This is relatively short window
and scheduling EH for probing is the first thing libata does after
initialization, so ignoring EH scheduling until initialization is
complete solves the problem nicely.

This problem was spotted by Berck E. Nash in the following thread.

  http://thread.gmane.org/gmane.linux.kernel/519412Signed-off-by: NTejun Heo <htejun@gmail.com>
Cc: Berck E. Nash <flyboy@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

The intention of using port_mask in SFF init helpers was to eventually
support exoctic configurations such as combination of legacy and
native port on the same controller.  This never became actually
necessary and the related code always has been subtly broken one way
or the other.  Now that new init model is in place, there is no reason
to make common helpers capable of handling all corner cases.  Exotic
cases can simply dealt within LLDs as necessary.

This patch removes port_mask handling in SFF init helpers.  SFF init
helpers don't take n_ports argument and interpret it into port_mask
anymore.  All information is carried via port_info.  n_ports argument
is dropped and always two ports are allocated.  LLD can tell SFF to
skip certain port by marking it dummy.  Note that SFF code has been
treating unuvailable ports this way for a long time until recent
breakage fix from Linus and is consistent with how other drivers
handle with unavailable ports.

This fixes 1-port legacy host handling still broken after the recent
native mode fix and simplifies SFF init logic.  The following changes
are made...

* ata_pci_init_native_host() and ata_init_legacy_host() both now try
  to initialized whatever they can and mark failed ports dummy.  They
  return 0 if any port is successfully initialized.

* ata_pci_prepare_native_host() and ata_pci_init_one() now doesn't
  take n_ports argument.  All info should be specified via port_info
  array.  Always two ports are allocated.

* ata_pci_init_bmdma() exported to be used by LLDs in exotic cases.

* port_info handling in all LLDs are standardized - all port_info
  arrays are const stack variable named ppi.  Unless the second port
  is different from the first, its port_info is specified as NULL
  (tells libata that it's identical to the last non-NULL port_info).

* pata_hpt37x/hpt3x2n: don't modify static variable directly.  Make an
  on-stack copy instead as ata_piix does.

* pata_uli: It has 4 ports instead of 2.  Don't use
  ata_pci_prepare_native_host().  Allocate the host explicitly and use
  init helpers.  It's simple enough.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Reimplement suspend/resume support using sdev->manage_start_stop.

* Device suspend/resume is now SCSI layer's responsibility and the
  code is simplified a lot.

* DPM is dropped.  This also simplifies code a lot.  Suspend/resume
  status is port-wide now.

* ata_scsi_device_suspend/resume() and ata_dev_ready() removed.

* Resume now has to wait for disk to spin up before proceeding.  I
  couldn't find easy way out as libata is in EH waiting for the
  disk to be ready and sd is waiting for EH to complete to issue
  START_STOP.

* sdev->manage_start_stop is set to 1 in ata_scsi_slave_config().
  This fixes spindown on shutdown and suspend-to-disk.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

libata previously depended upon waits in prereset to get resets after
hotplug right for both spin up and device ready wait.  This was
necessary both for reliablity and speed as reset was likely to fail if
initiated too early and each try usually took more than 30secs to
fail.  Previous patches fixed the reliability part by fixing status
and SCR handling in resets.  This patch remedies the speed part by
improving reset sequencing.

Prereset waiting timeout is adjusted to 10s because spinup wait is
replaced by reset sequencing and !BSY wait is not as important as
before.  During boot or module loading where the drive is already
fully spun up, !BSY wait succeeds immediately, so 10s should be enough
in most cases.  It matters after hotplugging or other error
conditions, but in those cases, !BSY wait in prereset simply can't be
relied upon due to the varied and weird behaviors ATA controllers and
devices show.

Reset is now driven by ata_eh_reset_timeouts[] table which contains
timeouts for each reset try.  The first reset can be softreset but the
following ones are always hardreset if available.  Each timeout
defines deadline for the reset try.  If a reset try fails, reset is
retried with the next timeout till the end of the timeout table is
reached.  If a reset try fails before the timeout with error, libata
waits till the deadline of the failed try before retrying.

IOW, the timeout table defines timetable of reset tries such that the
n'th try always begins at least after the sum of all previous timeouts
has passed.  The current timetable defines 4 tries and takes around 1
minute.

@0	: First try.  This should succeed most of the time during boot.
@10	: 10s is enough to spin up most consumer harddrives.  Give it
	  another shot.
@20	: 20s should spin up > 99% of working drives.  This has 30s
	  timeout for retarded devices needing long idleness post reset.
@55	: Final try with 5s timeout just in case.

The above timetable is trade off between not annoying the device too
much with frequent resets and taking reasonable amount of time in most
cases.  Some controllers may do better with shorter timeouts while
others may fare better with longer but we just can't rely upon LLD
writers to test each controller with wide variety of devices using
various scenarios.  We need default behavior which reasonably fits
most cases.

I've tested the above timetable on a dozen SATA controllers and a few
PATA controllers with about a dozen different drives from all major
vendors and 4 different ODDs from three different vendors for both
boot and hotplug (if available) cases.

Boot probing is not affected unless the device is broken in which
cases new code gives up on the port after a minute rather than five or
nine minutes.  When hotplugging, most devices get detected on the
first or second try.  Multi-platter drives with long spin up time
which sometimes took > 40 secs with the original code, now usually
comes up during the second try and at least right after the third try
@20.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Add @deadline to prereset and reset methods and make them honor it.
ata_wait_ready() which directly takes @deadline is implemented to be
used as the wait function.  This patch is in preparation for EH timing
improvements.

* ata_wait_ready() never does busy sleep.  It's only used from EH and
  no wait in EH is that urgent.  This function also prints 'be
  patient' message automatically after 5 secs of waiting if more than
  3 secs is remaining till deadline.

* ata_bus_post_reset() now fails with error code if any of its wait
  fails.  This is important because earlier reset tries will have
  shorter timeout than the spec requires.  If a device fails to
  respond before the short timeout, reset should be retried with
  longer timeout rather than silently ignoring the device.

  There are three behavior differences.

  1. Timeout is applied to both devices at once, not separately.  This
     is more consistent with what the spec says.

  2. When a device passes devchk but fails to become ready before
     deadline.  Previouly, post_reset would just succeed and let
     device classification remove the device.  New code fails the
     reset thus causing reset retry.  After a few times, EH will give
     up disabling the port.

  3. When slave device passes devchk but fails to become accessible
     (TF-wise) after reset.  Original code disables dev1 after 30s
     timeout and continues as if the device doesn't exist, while the
     patched code fails reset.  When this happens, new code fails
     reset on whole port rather than proceeding with only the primary
     device.

  If the failing device is suffering transient problems, new code
  retries reset which is a better behavior.  If the failing device is
  actually broken, the net effect is identical to it, but not to the
  other device sharing the channel.  In the previous code, reset would
  have succeeded after 30s thus detecting the working one.  In the new
  code, reset fails and whole port gets disabled.  IMO, it's a
  pathological case anyway (broken device sharing bus with working
  one) and doesn't really matter.

* ata_bus_softreset() is changed to return error code from
  ata_bus_post_reset().  It used to return 0 unconditionally.

* Spin up waiting is to be removed and not converted to honor
  deadline.

* To be on the safe side, deadline is set to 40s for the time being.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Separate ATA_EHI_DID_RESET into ATA_EHI_DID_SOFTRESET and
ATA_EHI_DID_HARDRESET.  ATA_EHI_DID_RESET is redefined as OR of the
two flags.  This patch doesn't introduce any behavior change.  This
will be used later to determine whether _SDD is necessary or not.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Signed-off-by: NAlan Cox <alan@redhat.com>

Add support for ignoring the BIOS HPA result (off by default) and setting
the disk to the full available size unless already frozen.

Tested with various platforms/disks and confirmed to work with the
Macintosh (which broke earlier) and ata_piix (breakage due to the LBA48
readback that Tejun fixed).

For normal users this brings us, I believe, to feature parity with old IDE
(and of course more featured in some areas too).
Signed-off-by: NJeff Garzik <jeff@garzik.org>

All drivers are converted to new init model.  Kill probe_ent,
ata_device_add() and ata_pci_init_native_mode().
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

These will be used to convert LLDs to new init model.

* Add irq_handler field to port_info.  In new init model, requesting
  IRQ is LLD's responsibility and libata doesn't need to know about
  irq_handler.  Most LLDs can simply register their irq_handler but
  some need different irq_handler depending on specific chip.  The
  added port_info->irq_handler field can be used by LLDs to select
  the matching IRQ handler in such cases.

* Add ata_dummy_port_info.

* Implement ata_pci_prepare_native_host(), a helper to alloc ATA host,
  acquire all resources and init the host in one go.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Convert native PCI host handling to alloc-init-register model.  New
function ata_pci_init_native_host() follows the new init model and
replaces ata_pci_init_native_mode().  As there are remaining LLD
users, the old function isn't removed yet.

ata_pci_init_one() is reimplemented using the new function and now
fully converted to new init model.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Implement ata_host_alloc_pinfo() and ata_host_register().  These helpers
will be used in the following patches to adopt new init model.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Reorganize ata_host_alloc() and its subroutines into the following
three functions.

* ata_host_alloc() : allocates host and its ports.  shost is not
  registered automatically.

* ata_scsi_add_hosts() : allocates and adds shosts associated with an
  ATA host.  Used by ata_host_register().

* ata_host_register() : takes a fully initialized ata_host structure
  and registers it to libata layer and probes it.

Only ata_host_alloc() and ata_host_register() are exported.
ata_device_add() is rewritten using the above functions.  This patch
does not introduce any observable behavior change.  Things worth
mentioning.

* print_id is assigned at registration time and LLDs are allowed to
  overallocate ports and reduce host->n_ports during initialization.
  ata_host_register() will throw away unused ports automatically.

* All SCSI host initialization stuff now resides in
  ata_scsi_add_hosts() in libata-scsi.c, where it should be.

* ipr is now the only user of ata_host_init().  Either kill it by
  converting ipr to use ata_host_alloc() and friends or rename and
  move it to libata-scsi.c
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Separate out ata_host_start() from ata_device_add().  ata_host_start()
calls ->port_start on each port if available and freezes the port.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Don't embed ap inside shost.  Allocate it separately and point it back
from shosts's hostdata.  This makes port allocation more flexible and
allows regular ATA and SAS share host alloc/init paths.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

The READ/WRITE LONG commands are theoretically obsolete,
but the majority of drives in existance still implement them.

The WRITE_LONG and WRITE_LONG_ONCE commands are of particular
interest for fault injection testing -- eg. creating "media errors"
at specific locations on a disk.

The fussy bit is that these commands require a non-standard
sector size, usually 520 bytes instead of 512.

This patch adds support to libata for READ/WRITE LONG commands
issued via SG_IO/ATA_16.
Signed-off-by: NMark Lord <mlord@pobox.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

With Tejun having added adev->ap some time ago we can get rid of the
almost unused port being passed to mode filters. And while we are
doing filters, lets turn on the !IORDY filter as well.
Signed-off-by: NAlan Cox <alan@redhat.com>

With some hand massaging from
Signed-off-by: NJeff Garzik <jeff@garzik.org>

This splits set_mode into do_set_mode and the wrapper so that a driver can
call the standard method inside its own.  This in theory also obsoletes
->post_set_mode().
Signed-off-by: NAlan Cox <alan@redhat.com>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: Tejun Heo <htejun@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

2.6.21-rc has horrible problems with libata and PATA cable types (and
thus speeds). This occurs because Tejun fixed a pile of other bugs and
we now do cable detect enforcement for drive side detection properly.

Unfortunately we don't do the process around cable detection right. Tejun
identified the problem and pointed to the right Annex in the spec, this patch
implements the rest of the needed changes.

We add a ->cable_detect() method called after the identify
sequence which allows a host to do host side detection at this point
should it wish, or to modify the results of the drive side identify.

This separate ->cable_detect method also cleans up a lot of code because
many drivers have their own error_handler methods which really just set
the cable type.

If there is no ->cable_detect method the cable type is left alone so a
driver setting it earlier (eg because it has the SATA flags set or
because it uses the old error_handler approach) will still do the right
thing (or at least the same thing) as before.

This patch simply adds the cable_detect method and helpers it doesn't use
them but other follow up patches will (ie Adrian please don't submit
patches to unexport them ;))
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

It used to be impossible to get from ata_device to ata_port but that is
no longer true. Various methods have been cleaned up over time but
dev_config still takes both and most users don't need both anyway. Tidy
this one up
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

To be used in sata_mv's exception handling code, and overall is a
generally useful function.
Signed-off-by: NJeff Garzik <jeff@garzik.org>