Put some information (and pointers to more) into the kernel's doc tree,
describing briefly the interface to the kernel's disk head unloading
facility. Information about how to set up a complete shock protection
system under GNU/Linux can be found on the web and is referenced
accordingly.

v3:
Here is some final polish including various spelling corrections
pointed out by Grant Grundler and Peter Moulder. Also, I have added some
information about the timing constraints related to disk head parking.
The patch looks more impressive than it really is and I think it would
be alright just to incorporate it into the original patch so as not to
clutter up the git log.
Signed-off-by: Elias Oltmanns <eo@nebensachen.de>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Tejun Heo <htejun@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

On user request (through sysfs), the IDLE IMMEDIATE command with UNLOAD
FEATURE as specified in ATA-7 is issued to the device and processing of
the request queue is stopped thereafter until the specified timeout
expires or user space asks to resume normal operation. This is supposed
to prevent the heads of a hard drive from accidentally crashing onto the
platter when a heavy shock is anticipated (like a falling laptop expected
to hit the floor). Port resets are deferred whenever a device on that
port is in the parked state.

v3:
Elias Oltmanns <eo@nebensachen.de> wrote:
[...]
> >> 1. Make sure that no negative value is being passed to
> >>    jiffies_to_msecs() in ide_park_show().
> >> 2. Drop the superfluous variable hwif in ide_special_rq().
> >> 3. Skip initialisation of task and tf in ide_special_rq() if we are not
> >>    handling a (un)park request.
> >
> > Well, #3 should have been done differently because we donn't want to
> > check for REQ_(UN)?PARK_HEADS more often than is necessary.
> 
> While preparing the backport to 2.6.27, it has just occurred to me that
> we need to clear the IDE_DFLAG_PARKED flag in ide_disk_pre_reset()
> because this flag must not be set after *any* sort of access to the
> device.

v4:
Fix a memory leak due to a missing blk_put_request() in
issue_park_cmd(). Additionally, we should plug the queue when enqueueing
the unpark request because there is no guarantee that the park timeout
has not expired by then. Even though the chance for that to happen is
very slim, the request might end up hanging in the queue until the next
I/O operation is queued up. While at it, clean up the code a little:
- make issue_park_cmd() a function of type void since nobody cares for
  the return value anyway;
- use blk_start_queueing() instead of __blk_run_queue() since we don't
  have to worry about recursion;
- remove a superfluous pointer deference in task_no_data_intr().
Signed-off-by: Elias Oltmanns <eo@nebensachen.de>
Cc: Jeff Garzik <jeff@garzik.org>,
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Tejun Heo <htejun@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Signed-off-by: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Borislav Petkov <petkovbb@googlemail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Signed-off-by: Herton Ronaldo Krzesinski <herton@mandriva.com.br>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

There should be no functional change resulting from this patch.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

There should be no functionality change resulting from this patch.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

This flag is to accomodate ide-cd functionality into ide atapi.

There should be no functionality change resulting from this patch.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
[bart: no need to zero debug_mask + move it next to module_param()]
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Also,

- leave in the possibility for optimizing away all debugging macros
- add a PFX macro and prepend all printk calls with it for consistency
- add debug macro calls in important driver paths
- remove #if 0-ed code
- mv restore_request -> ide_cd_restore_request
- add a driver registration printk

v2:
failed_command can be NULL so check it before accessing it

v3:
fix another NULL ptr in debug statement

There should be no functionality change resulting from this patch.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

- s/HWIF(drive)/drive->hwif/
- s/HWGROUP(drive)/[drive->]hwif->hwgroup/
- fixup error messages in ide_dma_intr() & dma_timer_expiry()
- fix checkpatch.pl errors/warnings
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

- use for_each_sg()
- move printing 'DMA table too small' message below use_pio_instead label
- merge '64KB bug' comment with function documentation
- fix intendation

There should be no functional changes caused by this patch.
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Follow-up to commit 5c05ff68
("ide: switch to DMA-mapping API"):

* pci_{alloc,free}_consistent() -> dma_{alloc,free}_coherent()
  in ide_{allocate,release}_dma_engine().

* Add ->prd_max_nents and ->prd_ent_size fields to ide_hwif_t
  (+ set default values in ide_allocate_dma_engine()).

* Make ide_{allocate,release}_dma_engine() available also
  for CONFIG_BLK_DEV_IDEDMA_SFF=n.  Then convert au1xxx-ide.c,
  scc_pata.c and sgiioc4.c to use them.

* Add missing ->init_dma method to scc_pata.

This patch also fixes:
- ->dmatable_cpu leak for au1xxx-ide
- too early realease of ->dmatable_cpu for scc_pata
- wrong amount of ->dmatable_cpu memory being freed for sgiioc4

While at it:
- remove superfluous ->dma_base check from ide_unregister()
- return -ENOMEM on error in ide_release_dma_engine()
- beautify error message in ide_release_dma_engine()
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Make ide_dma_timeout() available also for CONFIG_BLK_DEV_IDEDMA_SFF=n
and convert {ics,au1xxx-}ide.c to use it.

While at it:
- dump ATA Status register content on error
- use EXPORT_SYMBOL_GPL() to match the rest of SFF DMA functions
Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Make ide_dma_lost_irq() available also for CONFIG_BLK_DEV_IDEDMA_SFF=n
and convert {ics,au1xxx-}ide.c to use it.

While at it:
- use EXPORT_SYMBOL_GPL() to match the rest of SFF DMA functions
Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

While at it:
- use EXPORT_SYMBOL_GPL() to match the rest of SFF DMA functions
Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

hwif->sg_nents is always != 0 when this function is called
and there is also no need to explicitely zero hwif->sg_nents.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

In function ide_devset_execute() we should use __GFP_WAIT rather than
GFP_KERNEL. Also, the allocation cannot possibly fail at that point.
More importantly, there is a potential memory leak in the device probing
code. The infrastructure seems rather complex and I hope I haven't messed
anything up by trying to fix this.
Signed-off-by: Elias Oltmanns <eo@nebensachen.de>
[bart: remove superfluous ide_lock taking]
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

While at it:
- idedisk_capacity() -> ide_disk_capacity()
- idedisk_proc[] -> ide_disk_proc[]
- idedisk_settings[] -> ide_disk_settings[]

v2/3:
Build fix for CONFIG_IDE_PROC_FS=n from Elias Oltmanns.
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

While at it:
- idedisk_ioctl() -> ide_disk_ioctl()
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

While at it:
- idefloppy_capacity() -> ide_floppy_capacity()
- idefloppy_proc[] -> ide_floppy_proc[]
- idefloppy_settings[] -> ide_floppy_settings[]

v2:
Build fix for CONFIG_IDE_PROC_FS=n from Elias Oltmanns.

Cc: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

While at it:
- idefloppy_ioctl() -> ide_floppy_ioctl()

v2:
Fix for idefloppy_ioctl name change from Stephen Rothwell.

Cc: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Cc: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Set IDE_AFLAG_DRQ_INTERRUPT in do_identify() instead of ATAPI
device drivers *_setup() methods.

While at it:
- use ata_id_cdb_intr()

There should be no functional changes caused by this patch.

Cc: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

* Remove no longer used ide_host_alloc_all().

* Add MAX_HOST_PORTS define and use it instead of MAX_HWIFS
  as the maximum number of host ports possible.
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

There is now a generic solution [ide_generic_check_pci_legacy_iobases()]
so MIPS-specific ide_probe_legacy() is no longer necessary.

Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

* Rename ->ide_dma_clear_irq method to ->clear_irq
  and move it from ide_hwif_t to struct ide_port_ops.

* Move ->waiting_for_dma check inside ->clear_irq method.

* Move ->dma_base check inside ->clear_irq method.

piix.c:
* Add ich_port_ops and remove init_hwif_ich() wrapper.

There should be no functional changes caused by this patch.
Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Noticed-by: Russell King <rmk+lkml@arm.linux.org.uk>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

* Add 'struct task_s' to ide_hwif_t and init it to the current command
  in do_rw_taskfile().

* Merge all TASKFILE_NO_DATA data phase handlers into taskfile_no_intr().
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Factor out reset error reporting from reset_pollfunc()
to ide_reset_report_error() helper.

While at it:
- fix KERN_* printk() levels
- remove 'switch ()'
Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

* Convert 'pio_mode' device setting to use DS_SYNC flag.

* Remove unused special_t.b.{set_tune,serviced} and ide_drive_t.tune_req.
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

* Use 'drive->dn & 1' in ide_init_disk().

* remove [ata_]select_t.

While at it:

* Use ATA_DEVICE_OBS define in ide_port_init_devices_data().
Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

* Call ide_port_init_devices() in ide_host_register()
  also if 'struct ide_port_info *d' is not available.

* Init drive->dn in ide_port_init_devices() instead of
  ide_probe_port() so it is valid also in ->init_dev.

* Pass device number to ide_dev_apply_params().

* Use 'drive->dn & 1' instead of drive->select.b.unit.

There should be no functional changes caused by this patch.
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Having CY82C693_DEBUG_INFO is enough nowadays.
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Remove dead CY82C693_SETDMA_CLOCK code and now not needed
init_chipset_cy82c693().
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

* Move ide*_pm_* enums from ide-io.c to <linux/ide.h>.

* idedisk_pm_* -> ide_pm_*

* ide_pm_state_* -> ide_pm_*

* No need to set ide_pm_* enums to the fixed values.

* Uppercase ide_pm_* enums.

* Fix/update comments.
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Add IDE_DFLAG_LBA device flag and use it instead of ->select.b.lba.

Since ->tf_load uses ->select.all for ATA Device/Head register this
fixes HDIO_DRIVE_TASK[FILE] ioctls for CHS commands on LBA devices.
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>