Add device persistent field dev->sdev and store the attached SCSI
device.  With hotplug, libata needs to know the attached SCSI device
to offline and detach it, but scsi_device_lookup() cannot be used
because libata will reuse SCSI ID numbers - dead but not gone devices
(due to zombie opens, etc...) interfere with the lookup.

dev->sdev doesn't hold reference to the SCSI device.  It's cleared
when the SCSI device goes away.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Add ap->hw_sata_spd_limit and initialize it once during the boot
initialization (or driver load initialization).  ap->sata_spd_limit is
reset to ap->hw_sata_spd_limit on hotplug.  This prevents spd limits
introduced by earlier devices from affecting new devices.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Lifetimes of some fields span over device plugging/unplugging.  This
patch moves such persistent fields to the top of ata_device and
separate them with ATA_DEVICE_CLEAR_OFFSET.  Fields above the offset
are initialized once during host initializatino while all other fields
are cleared before hotplugging.  Currently ->ap, devno and part of
flags are persistent.

Note that flags is partially cleared while holding host_set lock.
This is to synchronize with later warm plug implementation which will
record hotplug request in dev->flags.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Add hotplug related flags and eh_info/context fields.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Implement ata_eh_wait().  On return from this function, it's
guaranteed that the EH which was pending or in progress when the
function was called is complete - including the tailing part of SCSI
EH.  This will be used by hotplug and others to synchronize with EH.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Nudge host flag constants to make a room after ATA_FLAG_EH_PENDING.
New EH flag will be added.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

ATA_FLAG_IRQ_MASK was added when I did the original data transfer with
IRQ masked bits for PIO. It has since been replaced by ->pio_data_xfer
methods so should be removed so nobody uses it by mistake thinking it
still works.
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

We need to pass the device in order to do per device checks such as
32bit I/O enables. With the changes to include dev->ap we now don't have
to add parameters however just clean them up. Also add data_xfer methods
to the existing drivers except ata_piix (which is in the other block of
patches). If you reject the piix one just add a data_xfer to it...
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Fix the HSM error_mask mapping.

Changes:
- Better mapping in ac_err_mask()
- In HSM_ST_FIRST ans HSM_ST state, check ATA_ERR|ATA_DF and map it to AC_ERR_DEV instead of AC_ERR_HSM.
- In HSM_ST_FIRST and HSM_ST state, map DRQ=1 ERR=1 to AC_ERR_HSM.
- For PIO data in and DRQ=1 ERR=1, add check after the junk data block is read.
Signed-off-by: NAlbert Lee <albertcc@tw.ibm.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Now that all NCQ related stuff are in place, implement NCQ device
configuration and bump ATA_MAX_QUEUE to 32 thus activating NCQ
support.

Original implementation is from Jens Axboe.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Add ap->qc_active and ap->sactive, mask of all active qcs and libata's
view of the SActive register, respectively.  Also, implement
ata_qc_complete_multiple() which takes new qc_active mask and complete
multiple qcs according to the mask.

These will be used to track NCQ commands and complete them.  The
distinction between ap->qc_active and ap->sactive is also useful for
later PM implementation.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Rename ap->qactive to ap->qc_allocated.  This is to accomodate
addition of ap->qc_active, mask of active qcs.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Add NCQ related ATA/libata constants and macros.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Implement stock BMDMA error handling methods.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Implement new EH.  The exported interface is ata_do_eh() which is to
be called from ->error_handler and performs the following steps to
recover the failed port.

ata_eh_autopsy() : analyze SError/TF, determine the cause of failure
		   and required recovery actions and record it in
		   ap->eh_context
ata_eh_report()	 : report the failure to user
ata_eh_recover() : perform recovery actions described in ap->eh_context
ata_eh_finish()	 : finish failed qcs

LLDDs can customize error handling by modifying eh_context before
calling ata_do_eh() or, if necessary, doing so inbetween each major
steps by calling each step explicitly.
Signed-off-by: NTejun Heo <htejun@gmail.com>

struct ata_eh_info serves as the communication channel between
execution path and EH.  Execution path describes detected error
condition in ap->eh_info and EH recovers the port using it.  To avoid
missing error conditions detected during EH, EH makes its own copy of
eh_info and clears it on entry allowing error info to accumulate
during EH.

Most EH states including EH's copy of eh_info are stored in
ap->eh_context (struct ata_eh_context) which is owned by EH and thus
doesn't require any synchronization to access and alter.  This
standardized context makes it easy to integrate various parts of EH
and extend EH to handle multiple links (for PM).
Signed-off-by: NTejun Heo <htejun@gmail.com>

This patch implements ata_ering and uses it to define dev->ering.

ata_ering is a ring buffer which records libata errors - whether a
command was for normar IO request, err_mask and timestamp.  Errors are
recorded per-device in dev->ering.  This will be used by EH to
determine recovery actions.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Add ATA and libata flags to be used by new EH.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Update ata_scsi_error() for new EH.  ata_scsi_error() is responsible
for claiming timed out qcs and invoking ->error_handler in safe and
synchronized manner.  As the state of the controller is unknown if a
qc has timed out, the port is frozen in such cases.

Note that ata_scsi_timed_out() isn't used for new EH.  This is because
a timed out qc cannot be claimed by EH without freezing the port and
freezing the port in ata_scsi_timed_out() results in unnecessary
abortion of other active qcs.  ata_scsi_timed_out() can be removed
once all drivers are converted to new EH.

While at it, add 'TODO: kill' comments to old EH functions.
Signed-off-by: NTejun Heo <htejun@gmail.com>

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>

Add ATA_FLAG_EH_{PENDING|FROZEN}, ATA_ATA_QCFLAG_{FAILED|SENSE_VALID}
and ops->freeze, thaw, error_handler, post_internal_cmd() for new EH.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Implement ata_{port|dev}_printk() which prefixes the message with
proper identification string.  This change is necessary for later PM
support because devices and links should be identified differently
depending on how they are attached.

This also helps unifying device id strings.  Currently, there are two
forms in use (P is the port number D device number) - 'ataP(D):', and
'ataP: dev D '.  These macros also make it harder to forget proper ID
string (e.g. printing only port number when a device is in question).

Debug message handling can be integrated into these printk macros by
passing debug type and level via @lv.
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>

Kill now unused scr_{read|write|write_flush}() and sata_dev_present().
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>

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>

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>

Kill duplicate prototypes for ata_eh_qc_complete/retry() in libata.h.
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>

This will be used by LLDD hardreset implementation.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

As waiting for some register bits to change seems to be a common
operation shared by some controllers, implement helper function
ata_wait_register().  This function also takes care of register write
flushing.

Note that the condition is inverted, the wait is over when the masked
value does NOT match @val.  As we're waiting for bits to change, this
test is more powerful and allows the function to be used in more
places.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

@verbose was added to ata_reset_fn_t because AHCI complained during
probing if no device was attached to the port.  However, muting
failure message isn't the correct approach.  Reset methods are
responsible for detecting no device condition and finishing
successfully.  Now that AHCI softreset is fixed, kill @verbose.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>