Currently, SATA softresets should do link onlineness check before
actually performing SRST protocol but it doesn't really belong to
softreset.

This patch moves onlineness check in softreset to ata_eh_reset() and
ata_eh_followup_srst_needed() to clean up code and help future sata_mv
changes which need clear separation between SCR and TF accesses.

sata_fsl is peculiar in that its softreset really isn't softreset but
combination of hardreset and softreset.  This patch adds dummy private
->prereset to keep the current behavior but the driver really should
implement separate hard and soft resets and return -EAGAIN from
hardreset if it should be follwed by softreset.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Implement helpers to test whether PMP is supported, attached and
determine pmp number to use when issuing SRST to a link.  While at it,
move ata_is_host_link() so that it's together with the two new PMP
helpers.

This change simplifies LLDs and helps making PMP support optional.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Most of PMP support code is already in libata-pmp.c.  All that are in
libata-core.c are sata_pmp_port_ops and EXPORTs.  Move them to
libata-pmp.c.  Also, collect PMP related prototypes and declarations
in header files and move them right above of SFF stuff.

This change is to make PMP support optional.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Now that SFF support is completely separated out from the core layer,
it can be made optional.  Add CONFIG_ATA_SFF and let SFF drivers
depend on it.  If CONFIG_ATA_SFF isn't set, all codes in libata-sff.c
and data structures for SFF support are disabled.  This saves good
number of bytes for small systems.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Now that SFF assumptions are removed from core layer, dummy port_ops
can be slimmed down.  Chop it down.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Now that SFF assumptions are separated out from non-SFF reset
sequence, port_ops->sff_dev_select() is no longer necessary for
non-SFF controllers.  Kill ata_noop_dev_select() and ->sff_dev_select
initialization from base and other non-SFF port_ops.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Now that all SFF stuff is separated out of core layer, core layer
doesn't call ops->tf_read directly.  It gets called only via
ops->qc_fill_rtf() for non-SFF drivers.  This patch directly
implements private ops->qc_fill_rtf() for non-SFF controllers and kill
ops->tf_read().

This is much cleaner for non-SFF controllers as some of them have to
cache SFF register values in private data structure and report the
cached values via ops->tf_read().  Also, ops->tf_read() gets nasty for
controllers which don't have clear notion of TF registers when
operation is not in progress.

As this change makes default ops->qc_fill_rtf unnecessary, move
ata_sff_qc_fill_rtf() form ata_base_port_ops to ata_sff_port_ops where
it belongs.
Signed-off-by: NTejun Heo <htejun@gmail.com>

ata_qc_complete_multiple() took @finish_qc and called it on every qc
before completing it.  This was to give opportunity to update TF cache
before ata_qc_complete() tries to fill result_tf.  Now that result TF
is a separate operation, this is no longer necessary.

Update sata_sil24, which was the only user of this mechanism, such
that it implements its own ops->qc_fill_rtf() and drop @finish_qc from
ata_qc_complete_multiple().
Signed-off-by: NTejun Heo <htejun@gmail.com>

On command completion, ata_qc_complete() directly called ops->tf_read
to fill qc->result_tf.  This patch adds ops->qc_fill_rtf to replace
hardcoded ops->tf_read usage.

ata_sff_qc_fill_rtf() which uses ops->tf_read to fill result_tf is
implemented and set in ata_base_port_ops and other ops tables which
don't inherit from ata_base_port_ops, so this patch doesn't introduce
any behavior change.

ops->qc_fill_rtf() is similar to ops->sff_tf_read() but can only be
called when a command finishes.  As some non-SFF controllers don't
have TF registers defined unless they're associated with in-flight
commands, this limited operation makes life easier for those drivers
and help lifting SFF assumptions from libata core layer.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Previously, there were two ways to trigger follow-up SRST from
hardreset method - returning -EAGAIN and leaving all device classes
unmodified.  Drivers never used the latter mechanism and the only use
case for the former was when hardreset couldn't classify.

Drop the latter mechanism and let -EAGAIN mean "perform follow-up SRST
if classification is required".  This change removes unnecessary
follow-up SRSTs and simplifies reset implementations.
Signed-off-by: NTejun Heo <htejun@gmail.com>

If PMP fan-out reset fails and SCR isn't accessible, PMP should be
reset.  This used to be tested by sata_pmp_std_hardreset() and
communicated to EH by -ERESTART.  However, this logic is generic and
doesn't really have much to do with specific hardreset implementation.

This patch moves SCR access failure detection logic to ata_eh_reset()
where it belongs.  As this makes sata_pmp_std_hardreset() identical to
sata_std_hardreset(), the function is killed and replaced with the
standard method.
Signed-off-by: NTejun Heo <htejun@gmail.com>

SError used to be cleared in ->postreset.  This has small hotplug race
condition.  If a device is plugged in after reset is complete but
postreset hasn't run yet, its hotplug event gets lost when SError is
cleared.  This patch makes sata_link_resume() clear SError.  This
kills the race condition and makes a lot of sense as some PMP and host
PHYs don't work properly without SError cleared.

This change makes sata_pmp_std_{pre|post}_reset()'s unnecessary as
they become identical to ata_std counterparts.  It also simplifies
sata_pmp_hardreset() and ahci_vt8251_hardreset().
Signed-off-by: NTejun Heo <htejun@gmail.com>

Implement sata_std_hardreset(), which simply wraps around
sata_link_hardreset().  sata_std_hardreset() becomes new standard
hardreset method for sata_port_ops and sata_sff_hardreset() moves from
ata_base_port_ops to ata_sff_port_ops, which is where it really
belongs.

ata_is_builtin_hardreset() is added so that both
ata_std_error_handler() and ata_sff_error_handler() skip both builtin
hardresets if SCR isn't accessible.

piix_sidpr_hardreset() in ata_piix.c is identical to
sata_std_hardreset() in functionality and got replaced with the
standard function.
Signed-off-by: NTejun Heo <htejun@gmail.com>

sata_sff_hardreset() contains link readiness wait logic which isn't
SFF specific.  Move that part into sata_link_hardreset(), which now
takes two more parameters - @online and @check_ready.  Both are
optional.  The former is out parameter for link onlineness after
reset.  The latter is used to wait for link readiness after hardreset.

Users of sata_link_hardreset() is updated to use new funtionality and
ahci_hardreset() is updated to use sata_link_hardreset() instead of
sata_sff_hardreset().  This doesn't really cause any behavior change.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Factor out waiting logic (which is common to all ATA controllers) from
ata_sff_wait_ready() into ata_wait_ready().  ata_wait_ready() takes
@check_ready function pointer and uses it to poll for readiness.  This
allows non-SFF controllers to use ata_wait_ready() to wait for link
readiness.

This patch also implements ata_wait_after_reset() - generic version of
ata_sff_wait_after_reset() - using ata_wait_ready().

ata_sff_wait_ready() is reimplemented using ata_wait_ready() and
ata_sff_check_ready().  Functionality remains the same.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Separate out generic ATA portion from ata_sff_postreset() into
ata_std_postreset() and implement ata_sff_postreset() using the std
version.

ata_base_port_ops now has ata_std_postreset() for its postreset and
ata_sff_port_ops overrides it to ata_sff_postreset().

This change affects pdc_adma, ahci, sata_fsl and sata_sil24.  pdc_adma
now specifies postreset to ata_sff_postreset() explicitly.  sata_fsl
and sata_sil24 now use ata_std_postreset() which makes no difference
to them.  ahci now calls ata_std_postreset() from its own postreset
method, which causes no behavior difference.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Separate out generic ATA portion from ata_sff_prereset() into
ata_std_prereset() and implement ata_sff_prereset() using the std
version.  Waiting for device readiness is the only SFF specific part.

ata_base_port_ops now has ata_std_prereset() for its prereset and
ata_sff_port_ops overrides it to ata_sff_prereset().  This change can
affect pdc_adma, ahci, sata_fsl and sata_sil24.  pdc_adma implements
its own prereset using ata_sff_prereset() and the rest has hardreset
and thus are unaffected by this change.

This change reflects real world situation.  There is no generic way to
wait for device readiness for non-SFF controllers and some of them
don't have any mechanism for that.  Non-sff drivers which don't have
hardreset should wrap ata_std_prereset() and wait for device readiness
itself but there's no such driver now and isn't likely to be popular
in the future either.
Signed-off-by: NTejun Heo <htejun@gmail.com>

->sff_irq_clear() is called only from SFF interrupt handler, so there
is no reason to initialize it for non-SFF controllers.  Also,
ata_sff_irq_clear() can handle both BMDMA and non-BMDMA SFF
controllers.

This patch kills ata_noop_irq_clear() and removes it from base
port_ops and sets ->sff_irq_clear to ata_sff_irq_clear() in sff
port_ops instead of bmdma port_ops.
Signed-off-by: NTejun Heo <htejun@gmail.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>

ata_flush_code() hasn't been in use for quite some time now.  Kill it.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

ata_tf_to_lba[48]() currently return LBA in tf + 1 for
ata_read_native_max_address().  Make them return LBA and make it
global so that it can be used to read LBA off TF for other purposes.
ata_read_native_max_address() now adds 1 itself.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

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>

ata_dev_configure() isn't tied to any controller interface except for
the probe debug message printing at the end of the function.  Kill the
message.

This is to help separating out SFF support from core layer.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

* Move SFF related functions from libata-core.c to libata-sff.c.

  ata_[bmdma_]sff_port_ops, ata_devchk(), ata_dev_try_classify(),
  ata_std_dev_select(), ata_tf_to_host(), ata_busy_sleep(),
  ata_wait_after_reset(), ata_wait_ready(), ata_bus_post_reset(),
  ata_bus_softreset(), ata_bus_reset(), ata_std_softreset(),
  sata_std_hardreset(), ata_fill_sg(), ata_fill_sg_dumb(),
  ata_qc_prep(), ata_dump_qc_prep(), ata_data_xfer(),
  ata_data_xfer_noirq(), ata_pio_sector(), ata_pio_sectors(),
  atapi_send_cdb(), __atapi_pio_bytes(), atapi_pio_bytes(),
  ata_hsm_ok_in_wq(), ata_hsm_qc_complete(), ata_hsm_move(),
  ata_pio_task(), ata_qc_issue_prot(), ata_host_intr(),
  ata_interrupt(), ata_std_ports()

* Make ata_pio_queue_task() global as it's now called from
  libata-sff.c.

* Move SFF related stuff in include/linux/libata.h and
  drivers/ata/libata.h into one place.  While at it, move timing
  constants into the global enum definition and fortify comments a
  bit.

This patch strictly moves stuff around and as such doesn't cause any
functional difference.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

There is no reason to issue device select in read_id, it will be done
by ops->qc_issue() when IDENTIFY[_PACKET] is issued via
ata_exec_internal().
Signed-off-by: NTejun Heo <htejun@gmail.com>
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>

port_info->private_data is currently used for two purposes - to record
private data about the port_info or to specify host->private_data to
use when allocating ata_host.

This overloading is confusing and counter-intuitive in that
port_info->private_data becomes host->private_data instead of
port->private_data.  In addition, port_info and host don't correspond
to each other 1-to-1.  Currently, the first non-NULL
port_info->private_data is used.

This patch makes port_info->private_data just be what it is -
private_data for the port_info where LLD can jot down extra info.
libata no longer sets host->private_data to the first non-NULL
port_info->private_data, @host_priv argument is added to
ata_pci_init_one() instead.  LLDs which use ata_pci_init_one() can use
this argument to pass in pointer to host private data.  LLDs which
don't should use init-register model anyway and can initialize
host->private_data directly.

Adding @host_priv instead of using init-register model for LLDs which
use ata_pci_init_one() is suggested by Alan Cox.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>

ata_pci_init_one() is the only function which uses ops->irq_handler
and pi->sht.  Other initialization functions take the same information
as arguments.  This causes confusion and duplicate unused entries in
structures.

Make ata_pci_init_one() take sht as an argument and use ata_interrupt
implicitly.  All current users use ata_interrupt and if different irq
handler is necessary open coding ata_pci_init_one() using
ata_prepare_sff_host() and ata_activate_sff_host can be done under ten
lines including error handling and driver which requires custom
interrupt handler is likely to require custom initialization anyway.

As ata_pci_init_one() was the last user of ops->irq_handler, this
patch also kills the field.
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>

->irq_clear() is used to clear IRQ bit of a SFF controller and isn't
useful for drivers which don't use libata SFF HSM implementation.
However, it's a required callback and many drivers implement their own
noop version as placeholder.  This patch implements ata_noop_irq_clear
and use it to replace those custom placeholders.

Also, SFF drivers which don't support BMDMA don't need to use
ata_bmdma_irq_clear().  It becomes noop if BMDMA address isn't
initialized.  Convert them to use ata_noop_irq_clear().
Signed-off-by: NTejun Heo <htejun@gmail.com>

ata_ehi_schedule_probe() was created to hide details of link-resuming
reset magic.  Now that all the softreset workarounds are gone,
scheduling probe is very simple - set probe_mask and request RESET.
Kill ata_ehi_schedule_probe() and open code it.  This also increases
consistency as ata_ehi_schedule_probe() couldn't cover individual
device probings so they were open-coded even when the helper existed.

While at it, define ATA_ALL_DEVICES as mask of all possible devices on
a link and always use it when requesting probe on link level for
simplicity and consistency.  Setting extra bits in the probe_mask
doesn't hurt anybody.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Some controllers can't reliably record the initial D2H FIS after SATA
link is brought online for whatever reason.  Advanced controllers
which don't have traditional TF register based interface often have
this problem as they don't really have the TF registers to update
while the controller and link are being initialized.

SKIP_D2H_BSY works around the problem by skipping the wait for device
readiness before issuing SRST, so for such controllers libata issues
SRST blindly and hopes for the best.

Now that libata defaults to hardreset, this workaround is no longer
necessary.  For controllers which have support for hardreset, SRST is
never issued by itself.  It is only issued as follow-up SRST for
device classification and PMP initialization, so there's no need to
wait for it from prereset.

Kill ATA_LFLAG_SKIP_D2H_BSY.
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>

SAT passthrus don't really fit into ATAPI_MISC class.  SAT passthru
commands always transfer multiple of 512 bytes and variable length
response is not allowed.  This patch creates a separate category -
ATAPI_PASS_THRU - for these.

This fixes HSM violation on "hdparm -I".
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Uninline atapi_cmd_type().  It doesn't really have to be inline and
more case will be added which need to access unexported libata
variable.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Commit f58229f8 accidentally made
ata_bus_probe() not use reverse order probing.  Fix it.

There currently isn't any PATA driver which uses obsolete
ata_bus_probe() path, so this patch is mainly for correctness.
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

EH actions are ATA_EH_* not ATA_EHI_*.  Rename ATA_EHI_LPM to
ATA_EH_LPM.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Cc: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

There's no point in retrying and eventually failing device detection
when the device rejects READ_NATIVE_MAX[_EXT].  Disable HPA unlocking
if READ_NATIVE_MAX[_EXT] is rejected as done when SET_MAX[_EXT] is
rejected.

This allows some old drives to work even if they aren't blacklisted.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

This is to fix bugzilla #10254.  QSI cdrom attached to pata_sis as
secondary master appears as phantom device for the slave.
Interestingly, instead of not setting DRQ after IDENTIFY which
triggers NODEV_HINT, it aborts both IDENTIFY and IDENTIFY PACKET which
makes EH retry.

Modify EH such that it assumes no device is attached if both flavors
of IDENTIFY are aborted by the device.  There really isn't much point
in retrying when the device actively aborts the commands.

While at it, convert NODEV detection message to ata_dev_printk() to
help debugging obscure detection problems.

This problem was reported by Jan Bücken.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Cc: Jan Bücken <jb.faq@gmx.de>
Acked-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>