Some time ago we had to disable init_hwif callback for PowerPC builds.
That was because of a historical IRQ overwrite in the driver, which
was causing IDE malfunction on the MPC8610HPCD PowerPC boards.

It's unclear whether this overwrite is still useful, but it is proven
to cause a bit of harm, and today some PowerPC targets (Xilinx ML510,
as reported by Roderick Colenbrander) need the init_hwif, so we have
to re-enable it and remove the overwrite.
Reported-by: Roderick Colenbrander <thunderbird2k@gmail.com>
Suggested-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Original patch (dfa4411c) was buggy.
This is a more proper fix which introduces blk_rq_quiet() macro
alleviating the need for dumb, too short caching variables.

Thanks to Helge Deller and Bart for debugging this.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Reported-and-tested-by: Helge Deller <deller@gmx.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

By a popular demand quilt tree was replaced by a git one.
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Remove superfluous commas and add missing whitespaces.
Noticed-by: Joe Perches <joe@perches.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Bugfixes noted by checking the code against the controller
documentation (TI document number SPRUE21):

 - Remove declarations for eight non-existent registers (!);
   and remove accesses to two of them.

 - Remove access to various non-existent bitfields in some of
   the registers which *do* exist (those fields must-be-zero).

 - Provide comment to replace bogus reset logic (removed above,
   it relied on non-existent bitfields).  Resets require GPIO
   help; this driver doesn't currently know about that.

With some minor cleanup:  relocate a comment, avoid an extra
lookup of the PIO timings.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

On Tuesday 14 April 2009 20:31:21 Subrata Modak wrote:
> Observed the following build error:
> ---
> CC      drivers/macintosh/mediabay.o
> In file included from drivers/macintosh/mediabay.c:21:
> include/linux/ide.h:605: error: field ‘request_sense_rq’ has incomplete
> type
> make[2]: *** [drivers/macintosh/mediabay.o] Error 1
> make[1]: *** [drivers/macintosh] Error 2
> make: *** [drivers] Error 2
> ---

mediabay shouldn't include <linux/ide.h> unconditionally so
remove the superfluous include from mediabay.c (<asm/mediabay.h>
will pull <linux/ide.h> in for CONFIG_BLK_DEV_IDE_PMAC=y).
Reported-by: Subrata Modak <subrata@linux.vnet.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

My laptop (Acer Travelmate 660) always cuts the power when rebooting
which causes the disk to emergency-park it's head.

Add a dmi check to stop disk as for shutdown on this laptop.
Signed-off-by: Bruno Prémont <bonbons@linux-vserver.org>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

With 2.6.30-rc2 I face a kernel crash on the 32bit hppa architecture 
due to ide-cd when udev creates the device nodes at startup:

Kernel Fault: Code=26 regs=8ed34c40 (Addr=00000024)
IASQ: 00000000 00000000 IAOQ: 1034b5ac 1034b5b0
 IIR: 4ab30048    ISR: 00000000  IOR: 00000024
 CPU:        0   CR30: 8ed34000 CR31: ffff55ff
 ORIG_R28: 00000000
 IAOQ[0]: ide_complete_rq+0x2c/0x70
 IAOQ[1]: ide_complete_rq+0x30/0x70
 RP(r2): cdrom_newpc_intr+0x178/0x46c
Backtrace:
 [<1035c608>] cdrom_newpc_intr+0x178/0x46c
 [<1034c494>] ide_intr+0x1b0/0x214
 [<1016d284>] handle_IRQ_event+0x70/0x150
 [<1016d4b0>] __do_IRQ+0x14c/0x1cc
 [<102f7864>] superio_interrupt+0x88/0xbc
 [<1016d284>] handle_IRQ_event+0x70/0x150
 [<1016d4b0>] __do_IRQ+0x14c/0x1cc
 [<10112efc>] do_cpu_irq_mask+0x9c/0xd0
 [<10116068>] intr_return+0x0/0x4

This crash seems to happen due to an uninitialized variable "rc".
The compiler even warns about that:
  CC      drivers/ide/ide-cd.o                                                         
/mnt/sda4/home/cvs/parisc/git-kernel/linus-linux-2.6/drivers/ide/ide-cd.c: In function `cdrom_newpc_intr':
/mnt/sda4/home/cvs/parisc/git-kernel/linus-linux-2.6/drivers/ide/ide-cd.c:612: warning: `rc' might be used uninitialized in this function

After applying the trivial patch below, which just initializes 
the variable to zero, the kernel doesn't crash any longer:

Starting the hotplug events dispatcher: udevd.
Synthesizing the initial hotplug events...
hda: command error: status=0x51 { DriveReady SeekComplete Error }
hda: command error: error=0x54 <3>{ AbortedCommand LastFailedSense=0x05 }
ide: failed opcode was: unknown
done.
Signed-off-by: Helge Deller <deller@gmx.de>
Acked-by: Borislav Petkov <petkovbb@gmail.com>
Cc: Linus <torvalds@linux-foundation.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Fix UDMA throughput bug:  tCYC averages t2CYCTYP/2, but the code
previously assumed it was the same as t2CYCTYP.  (That is, it was
using just one clock edge, not both.)  Move the table's type
declaration so it's adjacent to the table, making it more clear
what those numbers mean.

On one system this change increased throughput by almost 4x: UDMA/66
sometimes topped 23 MB/sec (on a drive known to do much better).  On
another system it was around a 10% win (UDMA/66 up to 7+ MB/sec).

The difference might be caused by the ratio between memory and IDE
clocks.  In the system with large speedup, this was exactly 2 (as a
workaround for a rev 1.1 silicon bug).  The other system used a more
standard ratio of 1.63 (and rev 2.1 silicon) ... clock domain synch
might have some issues, they're not unheard-of.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Impact: drop unnecessary code

Now that everything uses bio and block operations, there is no need to
reset request fields manually when retrying a request.  Every field is
guaranteed to be always valid.  Drop unnecessary request field
resetting from ide_dma_timeout_retry().
Signed-off-by: Tejun Heo <tj@kernel.org>

Impact: remove code path which is no longer necessary

All IDE data transfers now use rq->bio.  Simplify ide_map_sg()
accordingly.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>

Impact: remove fields and code paths which are no longer necessary

Now that ide-tape uses standard mechanisms to transfer data, special
case handling for bh handling can be dropped from ide-atapi.  Drop the
followings.

* pc->cur_pos, b_count, bh and b_data
* drive->pc_update_buffers() and pc_io_buffers().
Signed-off-by: Tejun Heo <tj@kernel.org>

Impact: cleanup

idetape_chrdev_read/write() functions are unnecessarily complex when
everything can be handled in a single loop.  Collapse
idetape_add_chrdev_read/write_request() into the rw functions and
simplify the implementation.
Signed-off-by: Tejun Heo <tj@kernel.org>

Impact: cleanup

Byte size is what most issue functions deal with, make
idetape_queue_rw_tail() and its wrappers take byte size instead of
sector counts.  idetape_chrdev_read() and write() functions are
converted to use tape->buffer_size instead of ctl from tape->cap.

This cleans up code a little bit and will ease the next r/w
reimplementation.
Signed-off-by: Tejun Heo <tj@kernel.org>

Impact: cleanup

Read and write init paths are almost identical.  Unify them into
idetape_init_rw().
Signed-off-by: Tejun Heo <tj@kernel.org>

Impact: kill now unnecessary idetape_bh

With everything using standard mechanisms, there is no need for
idetape_bh anymore.  Kill it and use tape->buf, cur and valid to
describe data buffer instead.

Changes worth mentioning are...

* idetape_queue_rq_tail() now always queue tape->buf and and adjusts
  buffer state properly before completion.

* idetape_pad_zeros() clears the buffer only once.
Signed-off-by: Tejun Heo <tj@kernel.org>

Impact: use standard way to transfer data

ide-tape uses rq in an interesting way.  For r/w requests, rq->special
is used to carry a private buffer management structure idetape_bh and
rq->nr_sectors and current_nr_sectors are initialized to the number of
idetape blocks which isn't necessary 512 bytes.  Also,
rq->current_nr_sectors is used to report back the residual count in
units of idetape blocks.

This peculiarity taxes both block layer and ide.  ide-atapi has
different paths and hooks to accomodate it and what a rq means becomes
quite confusing and making changes at the block layer becomes quite
difficult and error-prone.

This patch makes ide-tape use bio instead.  With the previous patch,
ide-tape currently is using single contiguos buffer so replacing it
isn't difficult.  Data buffer is mapped into bio using
blk_rq_map_kern() in idetape_queue_rw_tail().  idetape_io_buffers()
and idetape_update_buffers() are dropped and pc->bh is set to null to
tell ide-atapi to use standard data transfer mechanism and idetape_bh
byte counts are updated by the issuer on completion using the residual
count.

This change also nicely removes the FIXME in ide_pc_intr() where
ide-tape rqs need to be completed using ide_rq_bytes() instead of
blk_rq_bytes() (although this didn't really matter as the request
didn't have bio).
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <jens.axboe@oracle.com>

Impact: simpler buffer allocation and handling, kills OOM, fix DMA transfers

ide-tape has its own multiple buffer mechanism using struct
idetape_bh.  It allocates buffer with decreasing order-of-two
allocations so that it results in minimum number of segments.
However, the implementation is quite complex and works in a way that
no other block or ide driver works necessitating a lot of special case
handling.

The benefit this complex allocation scheme brings is questionable as
PIO or DMA the number of segments (16 maximum) doesn't make any
noticeable difference and it also doesn't negate the need for multiple
order allocation which can fail under memory pressure or high
fragmentation although it does lower the highest order necessary by
one when the buffer size isn't power of two.

As the first step to remove the custom buffer management, this patch
makes ide-tape allocate single continous buffer.  The maximum order is
four.  I doubt the change would cause any trouble but if it ever
matters, it should be converted to regular sg mechanism like everyone
else and even in that case dropping custom buffer handling and moving
to standard mechanism first make sense as an intermediate step.

This patch makes the first bh to contain the whole buffer and drops
multi bh handling code.  Following patches will make further changes.

This patch has the side effect of killing OOM triggered by allocation
path and fixing DMA transfers.  Previously, bug in alloc path
triggered OOM on command issue and commands were passed to DMA engine
without DMA-mapping all the segments.
Signed-off-by: Tejun Heo <tj@kernel.org>

Impact: allow residual count implementation in ->pc_callback()

rq->data_len has two duties - carrying the number of input bytes on
issue and carrying residual count back to the issuer on completion.
ide-atapi completion callback ->pc_callback() is the right place to do
this but currently ide-atapi depends on rq->data_len carrying the
original request size after calling ->pc_callback() to complete the pc
request.

This patch makes ide_pc_intr(), ide_tape_issue_pc() and
ide_floppy_issue_pc() cache length to complete before calling
->pc_callback() so that it can modify rq->data_len as necessary.

Note: As using rq->data_len for two purposes can make cases like this
      incorrect in subtle ways, future changes will introduce separate
      field for residual count.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <jens.axboe@oracle.com>

Impact: fix infinite retry loop

After a command failed, ide-tape and floppy inserts REQUEST_SENSE in
front of the failed command and according to the result, sets
pc->retries, flags and errors.  After REQUEST_SENSE is complete, the
failed command is again at the front of the queue and if the verdict
was to terminate the request, the issue functions tries to complete it
directly by calling drive->pc_callback() and returning ide_stopped.

However, drive->pc_callback() doesn't complete a request.  It only
prepares for completion of the request.  As a result, this creates an
infinite loop where the failed request is retried perpetually.

Fix it by actually ending the request by calling ide_complete_rq().
Signed-off-by: Tejun Heo <tj@kernel.org>

Impact: cleanup rq->data usage

ide-pm uses rq->data to carry pointer to struct request_pm_state
through request queue and rq->special is used to carray pointer to
local struct ide_cmd, which isn't necessary.  Use rq->special for
request_pm_state instead and use local ide_cmd in
ide_start_power_step().
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>

Impact: unify request data buffer handling

rq->data is used mostly to pass kernel buffer through request queue
without using bio.  There are only a couple of places which still do
this in kernel and converting to bio isn't difficult.

This patch converts ide-cd and atapi to use bio instead of rq->data
for request sense and internal pc commands.  With previous change to
unify sense request handling, this is relatively easily achieved by
adding blk_rq_map_kern() during sense_rq prep and PC issue.

If blk_rq_map_kern() fails for sense, the error is deferred till sense
issue and aborts the failed command which triggered the sense.  Note
that this is a slim possibility as sense prep is done on each command
issue, so for the above condition to actually trigger, all preps since
the last sense issue till the issue of the request which would require
a sense should fail.

* do_request functions might sleep now.  This should be okay as ide
  request_fn - do_ide_request() - is invoked only from make_request
  and plug work.  Make sure this is the case by adding might_sleep()
  to do_ide_request().

* Functions which access the read sense data before the sense request
  is complete now should access bio_data(sense_rq->bio) as the sense
  buffer might have been copied during blk_rq_map_kern().

* ide-tape updated to map sg.

* cdrom_do_block_pc() now doesn't have to deal with REQ_TYPE_ATA_PC
  special case.  Simplified.

* tp_ops->output/input_data path dropped from ide_pc_intr().
Signed-off-by: Tejun Heo <tj@kernel.org>

Since we're issuing REQ_TYPE_SENSE now we need to allow those types of
rqs in the ->do_request callbacks. As a future improvement, sense_len
assignment might be unified across all ATAPI devices. Borislav to
check with specs and test.

As a result, get rid of ide_queue_pc_head() and
drive->request_sense_rq.

tj: * Init request sense ide_atapi_pc from sense request.  In the
      longer timer, it would probably better to fold
      ide_create_request_sense_cmd() into its only current user -
      ide_floppy_get_format_progress().

    * ide_retry_pc() no longer takes @disk.

CC: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
CC: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Preallocate a sense request in the ->do_request method and reinitialize
it only on demand, in case it's been consumed in the IRQ handler path.
The reason for this is that we don't want to be mapping rq to bio in
the IRQ path and introduce all kinds of unnecessary hacks to the block
layer.

tj: * Both user and kernel PC requests expect sense data to be stored
      in separate storage other than drive->sense_data.  Copy sense
      data to rq->sense on completion if rq->sense is not NULL.  This
      fixes bogus sense data on PC requests.

As a result, remove cdrom_queue_request_sense.

CC: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
CC: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

This is in preparation of removing the queueing of a sense request out
of the IRQ handler path.

Use struct request_sense as a general sense buffer for all ATAPI
devices ide-{floppy,tape,cd}.

tj: * blk_get_request(__GFP_WAIT) can't be called from do_request() as
      it can cause deadlock.  Converted to use inline struct request
      and blk_rq_init().

    * Added xfer / cdb len selection depending on device type.

    * All sense prep logics folded into ide_prep_sense() which never
      fails.

    * hwif->rq clearing and sense_rq used handling moved into
      ide_queue_sense_rq().

    * blk_rq_map_kern() conversion is moved to later patch.

CC: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
CC: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Impact: rq->buffer usage cleanup

ide-cd uses rq->buffer to carry pointer to the original request when
issuing REQUEST_SENSE.  Use rq->special instead.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>

Impact: rq->buffer usage cleanup

ide-atapi uses rq->buffer as private opaque value for internal special
requests.  rq->special isn't used for these cases (the only case where
rq->special is used is for ide-tape rw requests).  Use rq->special
instead.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>

Impact: rq->buffer usage cleanup

ide_raw_taskfile() directly uses rq->buffer to carry pointer to the
data buffer.  This complicates both block interface and ide backend
request handling.  Use blk_rq_map_kern() instead and drop special
handling for REQ_TYPE_ATA_TASKFILE from ide_map_sg().

Note that REQ_RW setting is moved upwards as blk_rq_map_kern() uses it
to initialize bio rw flag.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>

Impact: remove unnecessary code path

Block pc requests always use bio and rq->data is always NULL.  No need
to worry about !rq->bio cases in idefloppy_block_pc_cmd().  Note that
ide-atapi uses ide_pio_bytes() for bio PIO transfer which handle sg
fine.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>

Impact: code simplification

ide_cd_request_sense_fixup() clears the tail of the sense buffer if
the device didn't completely fill it.  This patch makes
cdrom_queue_request_sense() clear the sense buffer before issuing the
command instead of clearing it afterwards.  This simplifies code and
eases future changes.
Signed-off-by: Tejun Heo <tj@kernel.org>

Impact: removal of unused field

No one uses ide_cmd->special anymore.  Kill it.
Signed-off-by: Tejun Heo <tj@kernel.org>

ide doesn't have to worry about REQ_SOFTBARRIER.  Don't set it.
Signed-off-by: Tejun Heo <tj@kernel.org>

blk_start_queueing() is being phased out in favor of
[__]blk_run_queue().  Switch.
Signed-off-by: Tejun Heo <tj@kernel.org>

Impact: fix an oops which always triggers

ide_tape_issue_pc() assumed drive->pc isn't NULL on invocation when
checking for back-to-back request sense issues but drive->pc can be
NULL and even when it's not NULL, it's not safe to dereference it once
the previous command is complete because pc could have been freed or
was on stack.  Kill back-to-back REQUEST_SENSE detection.
Signed-off-by: Tejun Heo <tj@kernel.org>

Impact: subtle behavior change

For fs requests, rq is only carrier of bios and rq error status as a
whole doesn't mean much.  This is the reason why rq->errors is being
cleared on each partial completion of a request as on each partial
completion the error status is transferred to the respective bios.

For pc requests, rq->errors is used to carry error status to the
issuer and thus __end_that_request_first() doesn't clear it on such
cases.

The condition was fine till now as only fs and pc requests have used
bio and thus the bio completion path.  However, future changes will
unify data accesses to bio and all non fs users care about rq error
status.  Clear rq->errors on bio completion only for fs requests.

In general, the implicit clearing is a bit too subtle especially as
the meaning of rq->errors is completely dependent on low level
drivers.  Unifying / cleaning up rq->errors usage and letting llds
manage it would be better.  TODO comment added.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Jens Axboe <axboe@kernel.dk>

The driver somehow got merged with the initializer for the dma_sff_read_status()
method missing which caused kernel panic on bootup.

This should fix the kernel.org bug #13026...
Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Reported-by: Arnd Hannemann <hannemann@nets.rwth-aachen.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Freeing non-slab objects is bad and results in an oops.  Fix it.
Reported-and-tested-by: Andrew Price <andy@andrewprice.me.uk>
Cc: Theodore Tso <tytso@mit.edu>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>