With hotplug, every reset might be a probing reset and thus something
similar to probe_init() is needed.  prereset() method is called before
a series of resets to a port and is the counterpart of postreset().
prereset() can tell EH to use different type of reset or skip reset by
modifying ehc->i.action.

This patch also implements ata_std_prereset().  Most controllers
should be able to use this function directly or with some wrapping.
After hotplug, different controllers need different actions to resume
the PHY and detect the newly attached device.  Controllers can be
categorized as follows.

* Controllers which can wait for the first D2H FIS after hotplug.
  Note that if the waiting is implemented by polling TF status, there
  needs to be a way to set BSY on PHY status change.  It can be
  implemented by hardware or with the help of the driver.

* Controllers which can wait for the first D2H FIS after sending
  COMRESET.  These controllers need to issue COMRESET to wait for the
  first FIS.  Note that the received D2H FIS could be the first D2H
  FIS after POR (power-on-reset) or D2H FIS in response to the
  COMRESET.  Some controllers use COMRESET as TF status
  synchronization point and clear TF automatically (sata_sil).

* Controllers which cannot wait for the first D2H FIS reliably.
  Blindly issuing SRST to spinning-up device often results in command
  issue failure or timeout, causing extended delay.  For these
  controllers, ata_std_prereset() explicitly waits ATA_SPINUP_WAIT
  (currently 8s) to give newly attached device time to spin up, then
  issues reset.  Note that failing to getting ready in ATA_SPINUP_WAIT
  is not critical.  libata will retry.  So, the timeout needs to be
  long enough to spin up most devices.

LLDDs can tell ata_std_prereset() which of above action is needed with
ATA_FLAG_HRST_TO_RESUME and ATA_FLAG_SKIP_D2H_BSY flags.  These flags
are PHY-specific property and will be moved to ata_link later.

While at it, this patch unifies function typedef's such that they all
have named arguments.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Implement NCQ support.

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

With NCQ, there are multiple sg tables, so pp->cmd_tbl_sg doesn't cut
it.  Directly calculate sg table address from pp->cmd_tbl.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Add HOST_CAP_NCQ.
Signed-off-by: NTejun Heo <htejun@gmail.com>

* Rename CMD_TBL_HDR to CMD_TBL_HDR_SZ as it's size not offset.

* Define MAX_CMDS and CMD_SZ and use them in calculation of other
  constants.

* Define CMD_TBL_AR_SZ as product of CMD_TBL_SZ and MAX_CMDS, and use
  it when calculating PRIV_DMA_SZ.

* CMD_SLOT_SZ is also dependent on MAX_CMDS but hasn't been changed
  because I didn't want to change the value used by the original code
  (32 commands).  Later NCQ change will bump MAX_CMDS to 32 anyway and
  the hard coded 32 can be changed to MAX_CMDS then.

* Reorder HOST_CAP_* flags.
Signed-off-by: NTejun Heo <htejun@gmail.com>

During multiblock PIO, multiple PIOS interrupts are generated before
qc compltion.  Current code prints unnecessary message for such cases.
This is exposed when new EH slows down attached device into PIO mode.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Convert AHCI to new EH.  Unfortunately, ICH7 AHCI reacts badly if IRQ
mask is diddled during operation.  So, freezing is implemented by
unconditionally clearing interrupt conditions while frozen.

* Interrupts are categorized according to required action.
  e.g. Connection status or unknown FIS error requires freezing the
  port while TF or HBUS_DATA don't.

* Only CONNECT (reflects SErr.X) interrupt is taken into account not
  PHYRDY (SErr.N), as CONNECT is better cue for starting EH.

* AHCI may be invoked without any active command.  e.g. CONNECT irq
  occuring while no qc in progress still triggers EH and will reset
  the port and revalidate attached device.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Use ATA printk helpers.
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>

Use new SCR and on/offline functions.  Note that for LLDD which know
it implements SCR callbacks, SCR functions are guaranteed to succeed
and ata_port_online() == !ata_port_offline().
Signed-off-by: NTejun Heo <htejun@gmail.com>

AHCI calls ata_dev_classify() even when no device is attached which
results in false class code.  Fix it.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Adds AHCI support for the VIA VT8251.

Includes a workaround for a hardware bug which requires a Command List
Override before softreset.
Signed-off-by: NBastiaan Jacques <b.jacques@planet.nl>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Replace ahci_poll_register() with ata_wait_register().
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>

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>

All softreset methods are responsible for detecting device presence
and succeed softreset in such cases.  AHCI didn't use to check for
device presence before proceeding with softreset and this caused
unnecessary reset retrials during probing.  This patch adds presence
detection to AHCI softreset.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

From: Anatoli Antonovitch <antonovi@ati.com>
Signed-off-by: NFelix Kuehling <fkuehlin@ati.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Now that libata is smart enought to handle both soft and hard resets,
add softreset method.
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>

Turn on AHCI_CMD_PREFETCH for PACKET commands.  This hints the
controller that it can prefetch the CDB and the PRD entries.  This
patch is originally from Jeff Garzik.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Fix NULL pointer dereference detected by the Coverity checker.  Kill
dev -> pdev -> dev conversion while at it.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Cc: Adrian Bunk <bunk@stusta.de>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

The previous dev->max_sectors patch made sht->max_sectors meaningless.
Kill all initializations of sht->max_sectors.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>

cdb_len is per-device property.  Sharing cdb_len on ap results in
inaccurate configuration on revalidation and hotplugging.  This patch
makes cdb_len per-device.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>

This patch converts all assert(xxx)'s in low-level drivers to
WARN_ON(!xxx)'s.  After this patch, there is no in-kernel user of the
libata assert() macro.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>

Convert ahci ->phy_reset to new reset mechanism.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>

Make ahci_fill_cmd_slot() take struct ahci_port_priv *pp instead of
struct ata_port *ap as suggested by Jeff Garzik.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>

Separate out ahci_fill_cmd_slot() from ahci_qc_prep().
ahci_fill_cmd_slot() can later be used to issue non-standard commands.
(e.g. softreset)
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>

->eng_timeout cannot be invoked with NULL qc anymore.  Add an
assertion in ata_scsi_error() and kill NULL qc handling from all
->eng_timeout callbacks.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>

Make all libata low level drivers use ata_scsi_timed_out().
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>

Isolate some PCI config register bitbanging to Intel hardware, as it
should have been all along.

Add support for JMicron JMB360.

Add constants needed to perform SRST.  This is preparation for adding
softreset method.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>

AHCI spec mandates engine to be stopped during hard resets.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>

Implement ata_eh_qc_complete/retry() using scsi_eh_finish_cmd() and
scsi_eh_flush_done_q().  This removes all eh scsicmd finish hacks from
low level drivers.

This change was first suggested by Jeff Garzik.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>

Add detailed AC_ERR_* flags and use them.  Long-term goal is to
describe all errors with err_mask and tf combination (tf for failed
sector information, etc...).  After proper error diagnosis is
implemented, sense data should also be generated from err_mask instead
of directly from hardware tf registers as it is currently.
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>

In ahci_host_intr err_mask is determined from IRQ status but never
used.  This patch sets qc->err_mask to the determined err_mask.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>

Separate out ahci_dev_classify().
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>

Separate out ahci_stop/start_engine().
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>