The following patch enhances libata to allow SAS device drivers
to utilize libata to talk to SATA devices. It introduces some
new APIs which allow libata to be used without allocating a
virtual scsi host.

New APIs:

ata_sas_port_alloc - Allocate an ata_port
ata_sas_port_init - Initialize an ata_port (probe device, etc)
ata_sas_port_destroy - Free an ata_port allocated by ata_sas_port_alloc
ata_sas_slave_configure - configure scsi device
ata_sas_queuecmd - queue a scsi command, similar to ata_scsi_queuecomand

These new APIs can be used either directly by a SAS LLDD or could be used
by the SAS transport class.

Possible usage for a SAS LLDD would be:

scsi_scan_host
	target_alloc
		ata_sas_port_alloc
	slave_alloc
		ata_sas_port_init
	slave_configure
		ata_sas_slave_configure

Commands received by the LLDD for SATA devices would call ata_sas_queuecmd.

Device teardown would occur with:

slave_destroy
	port_disable
target_destroy
	ata_sas_port_destroy
Signed-off-by: NBrian King <brking@us.ibm.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Move ata_probe_ent_alloc to libata-core. It will also be used by
future SAS/SATA integration patches.
Signed-off-by: NBrian King <brking@us.ibm.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Separate out the ata_port initialization from ata_host_init
so that it can be used in future SAS patches.
Signed-off-by: NBrian King <brking@us.ibm.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Make ata_do_simple_cmd() and ata_flush_cache() global.  These will be
used from libata-eh.c.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Update major version for libata, and several drivers.
Signed-off-by: NJeff Garzik <jeff@garzik.org>

This patch makes libata snoop 'SET FEATURES - WRITE CACHE
ENABLE/DISABLE' command, executing requisite revalidation processes
to update cached data.
Signed-off-by: NForrest Zhao <forrest.zhao@intel.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

With ops->probe_init() gone, no user is left in libata-core.c.  Move
ata_do_reset() to libata-eh.c and make it static.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Implement SCSI part of hotplug.

This must be done in a separate context as SCSI makes use of EH during
probing.  SCSI scan fails silently if EH is in progress.  In such
cases, libata pauses briefly and retries until every device is
attached.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Implement ata_eh_detach_dev().  This function is responsible for
detaching an ATA device and offlining the associated SCSI device
atomically so that the detached device is not accessed after ATA
detach is complete.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Hotplug will be implemented in libata-eh.c.  Make ata_dev_read_id()
and ata_dev_configure() global.
Signed-off-by: NTejun Heo <htejun@gmail.com>

It's best to run ATA hotplug from EH but attaching SCSI devices needs
working EH.  ata_aux_wq is used to give SCSI hotplug operations a
separate context.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Move initialization of struct ata_device into ata_dev_init() in
preparation for hotplug.  This patch calls ata_dev_init() from
ata_host_init() and thus makes no functional difference.
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>

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>

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

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

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>

@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>

Overriding the whole EH code is a per-transport, not per-host thing.
Move ->eh_strategy_handler to the transport class, same as
->eh_timed_out.

Downside is that scsi_host_alloc can't check for the total lack of EH
anymore, but the transition period from old EH where we needed it is
long gone already.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Convert the ATAPI_ENABLE_DMADIR compile time option needed
by some SATA-PATA bridge to runtime module parameter.
Signed-off-by: NAlbert Lee <albertcc@tw.ibm.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Make libata-core routines which will be used by EH implementation
extern.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

A lot of EH codes are about to be added to libata.  Separate out
libata-eh.c.  ata_scsi_timed_out(), ata_scsi_error(),
ata_qc_timeout(), ata_eng_timeout(), ata_eh_qc_complete() and
ata_eh_qc_retry() are moved.  No code is changed by this patch.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

There is no reason for the issuer to diddle with a failed qc as the
issuer has complete control over when a qc gets freed (usually in
->complete_fn).  Make ata_qc_issue() responsible for completing qcs
which failed to issue.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

SCSI midlayer has moved hostt->eh_timed_out to transport template.  As
libata doesn't need full-blown transport support yet, implement
minimal transport for libata.  No transport class or whatsoever, just
empty transport template with ->eh_timed_out hook.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

Implement port_task.  LLDD's can schedule a function to be executed
with context after specified delay.  libata core takes care of
synchronization against EH.  This is generalized form of pio_task and
packet_task which are tied to PIO hsm implementation.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Until problems are sorted.

This patch inlines ata_qc_complete() and uninlines __ata_qc_complete()
as suggested by Jeff Garzik.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>

Add ATA_QCFLAG_EH_SCHEDULED.  If this flag is set, the qc is owned by
EH and normal completion path is not allowed to finish it.  This patch
doesn't actually use this flag.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>

Return AC_ERR_* mask from issue fuctions instead of 0/-1.  This
enables things like failing a qc with AC_ERR_HSM when the device
doesn't set DRDY when the qc is about to be issued.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>

Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJens Axboe <axboe@suse.de>

There is no user of ata_qc_wait_err() and ata_qc_complete_noop() after
ata_exec_internal() changes.  Remove unused functions.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>

  - remove err_mask from the parameter list of the complete functions
  - move err_mask to ata_queued_cmd
  - initialize qc->err_mask when needed
  - for each function call to ata_qc_complete(), replace the err_mask parameter with qc->err_mask.
Signed-off-by: NAlbert Lee <albertcc@tw.ibm.com>

===============
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>

- Move ATAPI check-condition handling out of the timeout handler
- Use multi-qc-issue feature to issue REQUEST SENSE ATAPI PACKET
  command upon receiving an ATAPI check-condition.

This cleans things up a lot, and eliminates a nasty recursion bug.

Integrate ata_exec() and ata_tf_to_host() into their only caller,
ata_bus_edd().

Rename ata_tf_to_host_nolock() to ata_tf_to_host().

This makes locking a bit easier to review, and may help pave the way for
future changes.

The second argument to ata_qc_complete() was being used for two
purposes: communicate the ATA Status register to the completion
function, and indicate an error.  On legacy PCI IDE hardware, the latter
is often implicit in the former.  On more modern hardware, the driver
often completely emulated a Status register value, passing ATA_ERR as an
indication that something went wrong.

Now that previous code changes have eliminated the need to use drv_stat
arg to communicate the ATA Status register value, we can convert it to a
mask of possible error classes.

This will lead to more flexible error handling in the future.