As low-level drivers register their host controller(s), keep track
of the number of controllers and export thru /sys in a <host.port>
format so that udev can better match up port numbers with a
specific controller.

# pwd
/sys/devices/pci0000:00
# find . -name 'ata*' -print

(2nd controller with port multiplier attached)

./0000:00:1e.0/0000:05:01.0/ata2.7
./0000:00:1e.0/0000:05:01.0/ata2.7/link7/dev7.0/ata_device
./0000:00:1e.0/0000:05:01.0/ata2.7/link7/ata_link
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.0/dev7.0.0/ata_device
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.0/ata_link
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.1/dev7.1.0/ata_device
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.1/ata_link
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.2/dev7.2.0/ata_device
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.2/ata_link
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.3/dev7.3.0/ata_device
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.3/ata_link
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.4/dev7.4.0/ata_device
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.4/ata_link
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.5/dev7.5.0/ata_device
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.5/ata_link
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.6/dev7.6.0/ata_device
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.6/ata_link
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.7/dev7.7.0/ata_device
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.7/ata_link
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.8/dev7.8.0/ata_device
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.8/ata_link
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.9/dev7.9.0/ata_device
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.9/ata_link
./0000:00:1e.0/0000:05:01.0/ata2.7/ata_port
./0000:00:1e.0/0000:05:01.0/ata2.7/ata_port/ata2.7
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.10/dev7.10.0/ata_device
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.10/ata_link
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.11/dev7.11.0/ata_device
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.11/ata_link
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.12/dev7.12.0/ata_device
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.12/ata_link
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.13/dev7.13.0/ata_device
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.13/ata_link
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.14/dev7.14.0/ata_device
./0000:00:1e.0/0000:05:01.0/ata2.7/link7.14/ata_link
./0000:00:1e.0/0000:05:01.0/ata2.8
./0000:00:1e.0/0000:05:01.0/ata2.8/link8/dev8.0/ata_device
./0000:00:1e.0/0000:05:01.0/ata2.8/link8/ata_link
./0000:00:1e.0/0000:05:01.0/ata2.8/ata_port
./0000:00:1e.0/0000:05:01.0/ata2.8/ata_port/ata2.8

(1st controller)

./0000:00:1f.2/ata1.1
./0000:00:1f.2/ata1.1/link1/dev1.0/ata_device
./0000:00:1f.2/ata1.1/link1/ata_link
./0000:00:1f.2/ata1.1/ata_port
./0000:00:1f.2/ata1.1/ata_port/ata1.1
./0000:00:1f.2/ata1.2
./0000:00:1f.2/ata1.2/link2/dev2.0/ata_device
./0000:00:1f.2/ata1.2/link2/ata_link
./0000:00:1f.2/ata1.2/ata_port
./0000:00:1f.2/ata1.2/ata_port/ata1.2
./0000:00:1f.2/ata1.3
./0000:00:1f.2/ata1.3/link3/dev3.0/ata_device
./0000:00:1f.2/ata1.3/link3/ata_link
./0000:00:1f.2/ata1.3/ata_port
./0000:00:1f.2/ata1.3/ata_port/ata1.3
./0000:00:1f.2/ata1.4
./0000:00:1f.2/ata1.4/link4/dev4.0/ata_device
./0000:00:1f.2/ata1.4/link4/ata_link
./0000:00:1f.2/ata1.4/ata_port
./0000:00:1f.2/ata1.4/ata_port/ata1.4
./0000:00:1f.2/ata1.5
./0000:00:1f.2/ata1.5/link5/dev5.0/ata_device
./0000:00:1f.2/ata1.5/link5/ata_link
./0000:00:1f.2/ata1.5/ata_port
./0000:00:1f.2/ata1.5/ata_port/ata1.5
./0000:00:1f.2/ata1.6
./0000:00:1f.2/ata1.6/link6/dev6.0/ata_device
./0000:00:1f.2/ata1.6/link6/ata_link
./0000:00:1f.2/ata1.6/ata_port
./0000:00:1f.2/ata1.6/ata_port/ata1.6
Signed-off-by: NDavid Milburn <dmilburn@redhat.com>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

NCQ capability was used to check availability of SATA Settings page
from Identify Device Data Log, which contains DevSlp timing variables.
It does not work on some HDDs and leads to error messages.

IDENTIFY word 78 bit 5(Hardware Feature Control) can't work either
because it is only the sufficient condition of Identify Device data
log, not the necessary condition.

This patch replaced ata_device->sata_settings with ->devslp_timing
to only save DevSlp timing variables(8 bytes), instead of the whole
SATA Settings page(512 bytes).

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=51881Reported-by: NBorislav Petkov <bp@alien8.de>
Signed-off-by: NShane Huang <shane.huang@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

This relatively simple boiler-plate code is repeated in several platform
drivers. We should implement a common version in libata.
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Commit 66fa7f21 "libata-acpi: improve ACPI disabling" introdcued the
behaviour of disabling ATA ACPI if ata_acpi_on_devcfg failed the 2nd
time, but commit 30dcf76a dropped this behaviour and this caused
problem for Dimitris Damigos, where his laptop can not resume correctly.

The bugzilla page for it is:
https://bugzilla.kernel.org/show_bug.cgi?id=49331

The problem is, ata_dev_push_id will fail the 2nd time it is invoked,
and due to disabling ACPI code is dropped, ata_acpi_on_devcfg which
calls ata_dev_push_id will keep failing and eventually made the device
disabled.

This patch restores the original behaviour, if acpi failed the 2nd time,
disable acpi functionality for the device(and we do not event need to
add a debug message for this as it is still there ;-).
Reported-by: NDimitris Damigos <damigos@freemail.gr>
Signed-off-by: NAaron Lu <aaron.lu@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Device Sleep is a feature as described in AHCI 1.3.1 Technical Proposal.
This feature enables an HBA and SATA storage device to enter the DevSleep
interface state, enabling lower power SATA-based systems.

Aggressive Device Sleep enables the HBA to assert the DEVSLP signal as
soon as there are no commands outstanding to the device and the port
specific Device Sleep idle timer has expired. This enables autonomous
entry into the DevSleep interface state without waiting for software
in power sensitive systems.

This patch enables Aggressive Device Sleep only if both host controller
and device support it.

Tested on AMD reference board together with Device Sleep supported device
sample.
Signed-off-by: NShane Huang <shane.huang@amd.com>
Reviewed-by: NAaron Lu <aaron.lwe@gmail.com>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

libsas and ipr pass flags to ata_host_init that are meant for the port.

ata_host flags:
	ATA_HOST_SIMPLEX	= (1 << 0),	/* Host is simplex, one DMA channel per host only */
	ATA_HOST_STARTED	= (1 << 1),	/* Host started */
	ATA_HOST_PARALLEL_SCAN	= (1 << 2),	/* Ports on this host can be scanned in parallel */
	ATA_HOST_IGNORE_ATA	= (1 << 3),	/* Ignore ATA devices on this host. */

flags passed by libsas:
	ATA_FLAG_SATA		= (1 << 1),
	ATA_FLAG_PIO_DMA	= (1 << 7), /* PIO cmds via DMA */
	ATA_FLAG_NCQ		= (1 << 10), /* host supports NCQ */

The only one that aliases is ATA_HOST_STARTED which is a 'don't care' in
the libsas and ipr cases since ata_hosts from these sources are not
registered with libata.
Reported-by: NHannes Reinecke <hare@suse.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Acked-by: NBrian King <brking@us.ibm.com>
Acked-by: NJeff Garzik <jgarzik@redhat.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Reuse ata_port_{suspend|resume}_common for sas.  This path is chosen
over adding coordination between ata-tranport and sas-transport because
libsas wants to revalidate the domain at resume-time at the host level.
It can not validate links have resumed properly until libata has had a
chance to perform its revalidation, and any sane placing of an ata_port
in the sas-transport model would delay it's resumption until after the
host.

Export the common portion of port suspend/resume (bypass pm_runtime),
and allow sas to perform these operations asynchronously (similar to the
libsas async-ata probe implmentation).  Async operation is determined by
having an external, rather than stack based, location for storing the
result of the operation.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Reviewed-by: NJacek Danecki <jacek.danecki@intel.com>
Acked-by: NJeff Garzik <jgarzik@redhat.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Hotplug testing with libsas currently encounters a 55 second wait for
link recovery to give up.  In the case where the user trusts the
response time of their devices permit the recovery attempts to be
limited to one.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Acked-by: NJeff Garzik <jgarzik@redhat.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

When managing shost->host_eh_scheduled libata assumes that there is a
1:1 shost-to-ata_port relationship.  libsas creates a 1:N relationship
so it needs to manage host_eh_scheduled cumulatively at the host level.
The sched_eh and end_eh port port ops allow libsas to track when domain
devices enter/leave the "eh-pending" state under ha->lock (previously
named ha->state_lock, but it is no longer just a lock for ha->state
changes).

Since host_eh_scheduled indicates eh without backing commands pinning
the device it can be deallocated at any time.  Move the taking of the
domain_device reference under the port_lock to guarantee that the
ata_port stays around for the duration of eh.
Reviewed-by: NJacek Danecki <jacek.danecki@intel.com>
Acked-by: NJeff Garzik <jgarzik@redhat.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Add a new flag ATA_DFLAG_DA to indicate that device supports "Device
Attention".
Acked-by: NAaron Lu <aaron.lu@amd.com>
Signed-off-by: NLin Ming <ming.m.lin@intel.com>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Now that we have the ability to directly glue the ACPI namespace to the
driver model in libata, we don't need the custom code to handle the same
thing. Remove it and migrate the functions over to the new code.
Signed-off-by: NMatthew Garrett <mjg@redhat.com>
Signed-off-by: NHolger Macht <holger@homac.de>
Signed-off-by: NLin Ming <ming.m.lin@intel.com>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Where devices are visible via more than one host we sometimes wish to
indicate that cirtain devices should be ignored on a specific host.  Add a
host flag indicating that this host wishes to ignore ATA specific devices.
Signed-off-by: NAndy Whitcroft <apw@canonical.com>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

This changes the ordering of initialization and probing events from:
  1/ allocate rphy in PORTE_BYTES_DMAED, DISCE_REVALIDATE_DOMAIN
  2/ allocate ata_port and schedule port probe in DISCE_PROBE
...to:
  1/ allocate ata_port in PORTE_BYTES_DMAED, DISCE_REVALIDATE_DOMAIN
  2/ allocate rphy in PORTE_BYTES_DMAED, DISCE_REVALIDATE_DOMAIN
  3/ schedule port probe in DISCE_PROBE

This ordering prevents PHYE_SIGNAL_LOSS_EVENTS from sneaking in to
destrory ata devices before they have been fully initialized:

  BUG: unable to handle kernel paging request at 0000000000003b10
  IP: [<ffffffffa0053d7e>] sas_ata_end_eh+0x12/0x5e [libsas]
  ...
  [<ffffffffa004d1af>] sas_unregister_common_dev+0x78/0xc9 [libsas]
  [<ffffffffa004d4d4>] sas_unregister_dev+0x4f/0xad [libsas]
  [<ffffffffa004d5b1>] sas_unregister_domain_devices+0x7f/0xbf [libsas]
  [<ffffffffa004c487>] sas_deform_port+0x61/0x1b8 [libsas]
  [<ffffffffa004bed0>] sas_phye_loss_of_signal+0x29/0x2b [libsas]

...and kills the awkward "sata domain_device briefly existing in the
domain without an ata_port" state.
Reported-by: NMichal Kosciowski <michal.kosciowski@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Acked-by: NJeff Garzik <jgarzik@redhat.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

libsas ata error handling is already async but this does not help the
scan case.  Move initial link recovery out from under host->scan_mutex,
and delay synchronization with eh until after all port probe/recovery
work has been queued.

Device ordering is maintained with scan order by still calling
sas_rphy_add() in order of domain discovery.

Since we now scan the domain list when invoking libata-eh we need to be
careful to check for fully initialized ata ports.
Acked-by: NJack Wang <jack_wang@usish.com>
Acked-by: NJeff Garzik <jgarzik@redhat.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Link resets leave ata affiliations intact, so arrange for libsas to make
an effort to avoid dropping the device due to a slow-to-recover link.
Towards this end carry out reset in the host workqueue so that it can
check for ata devices and kick the reset request to libata.  Hard
resets, in contrast, bypass libata since they are meant for associating
an ata device with another initiator in the domain (tears down
affiliations).

Need to add a new transport_sas_phy_reset() since the current
sas_phy_reset() is a utility function to libsas lldds.  They are not
prepared for it to loop back into eh.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Standardize the style for compiler based printf format verification.
Standardized the location of __printf too.

Done via script and a little typing.

$ grep -rPl --include=*.[ch] -w "__attribute__" * | \
  grep -vP "^(tools|scripts|include/linux/compiler-gcc.h)" | \
  xargs perl -n -i -e 'local $/; while (<>) { s/\b__attribute__\s*\(\s*\(\s*format\s*\(\s*printf\s*,\s*(.+)\s*,\s*(.+)\s*\)\s*\)\s*\)/__printf($1, $2)/g ; print; }'

[akpm@linux-foundation.org: revert arch bits]
Signed-off-by: NJoe Perches <joe@perches.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pass queue_depth change requests to libata, and prevent queue_type
changes for ATA devices.

Otherwise:
1/ we do not honor the libata specific restrictions on the queue depth
2/ libsas drivers that do not set sdev->tagged_supported are unable to
   change the queue_depth of ata devices via sysfs
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Acked-by: NJeff Garzik <jgarzik@redhat.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Use a single mechanism to show driver version.
Reduces text a tiny bit too.

Remove uses of static int printed_version
Add and use ata_print_version(const struct device *, const char *ver)
and ata_print_version_once.

$ size drivers/ata/built-in.*
   text	   data	    bss	    dec	    hex	filename
 544969	  73893	 116584	 735446	  b38d6	drivers/ata/built-in.allyesconfig.ata.o
 543870	  73893	 116592	 734355	  b34ad	drivers/ata/built-in.allyesconfig.print_once.o
 141328	  14689	   4220	 160237	  271ed	drivers/ata/built-in.defconfig.ata.o
 141212	  14689	   4220	 160121	  27179	drivers/ata/built-in.defconfig.print_once.o
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>

Saves text by removing nearly duplicated text format strings by
creating ata_<foo>_printk functions and printf extension %pV.

ata defconfig size shrinks ~5% (~8KB), allyesconfig ~2.5% (~13KB)

Format string duplication comes from:

 #define ata_link_printk(link, lv, fmt, args...) do { \
       if (sata_pmp_attached((link)->ap) || (link)->ap->slave_link)    \
               printk("%sata%u.%02u: "fmt, lv, (link)->ap->print_id,   \
                      (link)->pmp , ##args); \
       else \
               printk("%sata%u: "fmt, lv, (link)->ap->print_id , ##args); \
       } while(0)

Coalesce long formats.

$ size drivers/ata/built-in.*
   text	   data	    bss	    dec	    hex	filename
 544969	  73893	 116584	 735446	  b38d6	drivers/ata/built-in.allyesconfig.ata.o
 558429	  73893	 117864	 750186	  b726a	drivers/ata/built-in.allyesconfig.dev_level.o
 141328	  14689	   4220	 160237	  271ed	drivers/ata/built-in.defconfig.ata.o
 149567	  14689	   4220	 168476	  2921c	drivers/ata/built-in.defconfig.dev_level.o
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>

Give users the option of completely powering off unoccupied
SATA ports using the existing min_power link_power_management_policy
option.  When the use selects this option on an empty port, we
will power the port off by setting DET to off.  For occupied ports,
behavior is unchanged.
Signed-off-by: NKristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>

NVIDIA mcp65 familiy of controllers cause command timeouts when DIPM
is used.  Implement ATA_FLAG_NO_DIPM and apply it.

This problem was reported by Stefan Bader in the following thread.

 http://thread.gmane.org/gmane.linux.ide/48841

stable: applicable to 2.6.37 and 38.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NStefan Bader <stefan.bader@canonical.com>
Cc: stable@kernel.org
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>

ATA_DFLAG_{H|D}IPM flags are no longer used.  Kill them.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>

Fixes generated by 'codespell' and manually reviewed.
Signed-off-by: NLucas De Marchi <lucas.demarchi@profusion.mobi>

This patch adds ata_sff_queue_work() & ata_sff_queue_delayed_work() routine in
libata-sff.c file. This routine can be used by ata drivers to use ata_sff_wq.
Signed-off-by: NViresh Kumar <viresh.kumar@st.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>

Commit 6b7ae954 (libata: reimplement link power
management) removed the check of ATA_FLAG_LPM but neglected to remove the flag
itself.  Do it now...
Signed-off-by: NSergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

All checks of ATA_FLAG_NO_LEGACY have been removed by the commits
c791c306 ([libata] minor PCI IDE probe
fixes and cleanups) and f0d36efd (libata:
update libata core layer to use devres), so I think it's time to finally
get rid of this flag...
Signed-off-by: NSergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Commit 0d5ff566 (libata: convert to iomap)
removed all checks of ATA_FLAG_MMIO but neglected to remove the flag itself.
Do it now, at last...
Signed-off-by: NSergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

These flags are marked as obsolete and the checks for them have been removed
by commit 29444088 (libata-sff: kill unused
ata_bus_reset()), so I think it's time to finally get rid of them...
Signed-off-by: NSergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Right at the moment, the libata error handler is incredibly
monolithic.  This makes it impossible to use from composite drivers
like libsas and ipr which have to handle error themselves in the first
instance.

The essence of the change is to split the monolithic error handler
into two components: one which handles a queue of ata commands for
processing and the other which handles the back end of readying a
port.  This allows the upper error handler fine grained control in
calling libsas functions (and making sure they only get called for ATA
commands whose lower errors have been fixed up).
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Right at the moment, the libata error handler is incredibly
monolithic.  This makes it impossible to use from composite drivers
like libsas and ipr which have to handle error themselves in the first
instance.

The essence of the change is to split the monolithic error handler
into two components: one which handles a queue of ata commands for
processing and the other which handles the back end of readying a
port.  This allows the upper error handler fine grained control in
calling libsas functions (and making sure they only get called for ATA
commands whose lower errors have been fixed up).

Cc: Tejun Heo <tj@kernel.org>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>

It's stored in struct scsi_cmnd->scsi_done, making several 'done'
parameters to functions redundant.
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Move the mid-layer's ->queuecommand() invocation from being locked
with the host lock to being unlocked to facilitate speeding up the
critical path for drivers who don't need this lock taken anyway.

The patch below presents a simple SCSI host lock push-down as an
equivalent transformation.  No locking or other behavior should change
with this patch.  All existing bugs and locking orders are preserved.

Additionally, add one parameter to queuecommand,
	struct Scsi_Host *
and remove one parameter from queuecommand,
	void (*done)(struct scsi_cmnd *)

Scsi_Host* is a convenient pointer that most host drivers need anyway,
and 'done' is redundant to struct scsi_cmnd->scsi_done.

Minimal code disturbance was attempted with this change.  Most drivers
needed only two one-line modifications for their host lock push-down.
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>
Acked-by: NJames Bottomley <James.Bottomley@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAndrea Gelmini <andrea.gelmini@gelma.net>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Reorder structure ata_queued_cmd to remove 8 bytes of alignment padding
on 64 bit builds & therefore reduce the size of structure ata_port by
256 bytes.

Overall this will have little impact, other than reducing the amount of
memory that is cleared when allocating ata_ports.
Signed-off-by: NRichard Kennedy <richard@rsk.demon.co.uk>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

In libata, the non-EH code paths should always take and release
ap->lock explicitly when accessing hardware or shared data structures.
However, once EH is active, it's assumed that the port is owned by EH
and EH methods don't explicitly take ap->lock unless race from irq
handler or other code paths are expected.  However, libata EH didn't
guarantee exclusion among EHs for ports of the same host.  IOW,
multiple EHs may execute in parallel on multiple ports of the same
controller.

In many cases, especially in SATA, the ports are completely
independent of each other and this doesn't cause problems; however,
there are cases where different ports share the same resource, which
lead to obscure timing related bugs such as the one fixed by commit
213373cf (ata_piix: fix locking around SIDPR access).

This patch implements exclusion among EHs of the same host.  When EH
begins, it acquires per-host EH ownership by calling ata_eh_acquire().
When EH finishes, the ownership is released by calling
ata_eh_release().  EH ownership is also released whenever the EH
thread goes to sleep from ata_msleep() or explicitly and reacquired
after waking up.

This ensures that while EH is actively accessing the hardware, it has
exclusive access to it while allowing EHs to interleave and progress
in parallel as they hit waiting stages, which dominate the time spent
in EH.  This achieves cross-port EH exclusion without pervasive and
fragile changes while still allowing parallel EH for the most part.

This was first reported by yuanding02@gmail.com more than three years
ago in the following bugzilla.  :-)

  https://bugzilla.kernel.org/show_bug.cgi?id=8223Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Reported-by: yuanding02@gmail.com
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Add optional @ap argument to ata_wait_register() and replace msleep()
calls with ata_msleep() which take optional @ap in addition to the
duration.  These will be used to implement EH exclusion.

This patch doesn't cause any behavior difference.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

The current LPM implementation has the following issues.

* Operation order isn't well thought-out.  e.g. HIPM should be
  configured after IPM in SControl is properly configured.  Not the
  other way around.

* Suspend/resume paths call ata_lpm_enable/disable() which must only
  be called from EH context directly.  Also, ata_lpm_enable/disable()
  were called whether LPM was in use or not.

* Implementation is per-port when it should be per-link.  As a result,
  it can't be used for controllers with slave links or PMP.

* LPM state isn't managed consistently.  After a link reset for
  whatever reason including suspend/resume the actual LPM state would
  be reset leaving ap->lpm_policy inconsistent.

* Generic/driver-specific logic boundary isn't clear.  Currently,
  libahci has to mangle stuff which libata EH proper should be
  handling.  This makes the implementation unnecessarily complex and
  fragile.

* Tied to ALPM.  Doesn't consider DIPM only cases and doesn't check
  whether the device allows HIPM.

* Error handling isn't implemented.

Given the extent of mismatch with the rest of libata, I don't think
trying to fix it piecewise makes much sense.  This patch reimplements
LPM support.

* The new implementation is per-link.  The target policy is still
  port-wide (ap->target_lpm_policy) but all the mechanisms and states
  are per-link and integrate well with the rest of link abstraction
  and can work with slave and PMP links.

* Core EH has proper control of LPM state.  LPM state is reconfigured
  when and only when reconfiguration is necessary.  It makes sure that
  LPM state is reset when probing for new device on the link.
  Controller agnostic logic is now implemented in libata EH proper and
  driver implementation only has to deal with controller specifics.

* Proper error handling.  LPM config failure is attributed to the
  device on the link and LPM is disabled for the link if it fails
  repeatedly.

* ops->enable/disable_pm() are replaced with single ops->set_lpm()
  which takes @policy and @hints.  This simplifies driver specific
  implementation.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Link power management is about to be reimplemented.  Prepare for it.

* Implement sata_link_scr_lpm().

* Drop static from ata_dev_set_feature() and make it available to
  other libata files.

* Trivial whitespace adjustments.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Link power management related symbols are in confusing state w/ mixed
usages of lpm, ipm and pm.  This patch cleans up lpm related symbols
and sysfs show/store functions as follows.

* lpm states - NOT_AVAILABLE, MIN_POWER, MAX_PERFORMANCE and
  MEDIUM_POWER are renamed to ATA_LPM_UNKNOWN and
  ATA_LPM_{MIN|MAX|MED}_POWER.

* Pre/postfixes are unified to lpm.

* sysfs show/store functions for link_power_management_policy were
  curiously named get/put and unnecessarily complex.  Renamed to
  show/store and simplified.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

This is a scheleton for libata transport class.
All information is read only, exporting information from libata:
- ata_port class: one per ATA port
- ata_link class: one per ATA port or 15 for SATA Port Multiplier
- ata_device class: up to 2 for PATA link, usually one for SATA.
Signed-off-by: NGwendal Grignou <gwendal@google.com>
Reviewed-by: NGrant Grundler <grundler@google.com>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>