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: NTejun Heo <tj@kernel.org>

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: NTejun 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: NBorislav Petkov <petkovbb@gmail.com>
Signed-off-by: NTejun 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: NBorislav Petkov <petkovbb@gmail.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

Impact: removal of unused field

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

Simplify tf_read() method, making it deal only with 'struct ide_taskfile' and
the validity flags that the upper layer passes, and factoring out the code that
deals with the high order bytes into ide_tf_readback() to be called from the
only two functions interested, ide_complete_cmd() and ide_dump_sector().

This should stop the needless code duplication in this method and so make
it about twice smaller than it was; along with simplifying the setup for
the method call, this should save both time and space...
Signed-off-by: NSergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Simplify tf_load() method, making it deal only with 'struct ide_taskfile' and
the validity flags that the upper layer passes, and moving the code that deals
with the high order bytes into the only function interested, do_rw_taskfile().

This should stop the needless code duplication in this method and so make
it about twice smaller than it was; along with simplifying the setup for the
method call, this should save both time and space...
Signed-off-by: NSergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Make 'struct ide_taskfile' cover only 8 register values and thus put two such
fields ('tf' and 'hob') into 'struct ide_cmd', dropping unnecessary 'tf_array'
field from it.

This required changing the prototype of ide_get_lba_addr() and ide_tf_dump().
Signed-off-by: NSergei Shtylyov <sshtylyov@ru.mvista.com>
[bart: fix setting of ATA_LBA bit for LBA48 commands in __ide_do_rw_disk()]
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Replace IDE_TFLAG_{IN|OUT}_* flags meaning to the taskfile register validity on
input/output by the IDE_VALID_* flags and introduce 4 symmetric 8-bit register
validity indicator subfields, 'valid.{input/output}.{tf|hob}', into the 'struct
ide_cmd' instead of using the 'tf_flags' field for that purpose (this field can
then be turned from 32-bit into 8-bit one).
Signed-off-by: NSergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Since SELECT_DRIVE() has boiled down to a mere dev_select() method call, it now
makes sense to just inline it...
Signed-off-by: NSergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Turn selectproc() method into dev_select() method by teaching it to write to the
device register and moving it from 'struct ide_port_ops' to 'struct ide_tp_ops'.
Signed-off-by: NSergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: benh@kernel.crashing.org
Cc: petkovbb@gmail.com
[bart: add ->dev_select to at91_ide.c and tx4939.c (__BIG_ENDIAN case)]
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>

The feature register has never been readable -- when its location is read, one
gets the error register value; hence rename IDE_TFLAG_IN_[HOB_]FEATURE into
IDE_TFLAG_IN_[HOB_]ERROR and introduce the 'hob_error' field into the 'struct
ide_taskfile' (despite the error register not really depending on the HOB bit).
Signed-off-by: NSergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Turn set_irq() method with its software reset hack into write_devctl() method
(for just writing a value into the device control register) at last...
Signed-off-by: NSergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>

* Fix ide_init_sg_cmd() setup for non-fs requests.

* Convert ide_pc_intr() to use ide_pio_bytes() for floppy media.

* Remove no longer needed ide_io_buffers() and sg/sg_cnt fields
  from struct ide_atapi_pc.

* Remove partial completions; kill idefloppy_update_buffers(), as a
  result.

* Add some more debugging statements.
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: NBorislav Petkov <petkovbb@gmail.com>
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>

struct ide_atapi_pc is often allocated on the stack and size of ->pc_buf
size is 256 bytes.  However since only ide_floppy_create_read_capacity_cmd()
and idetape_create_inquiry_cmd() require such size allocate buffers for
these pc-s explicitely and decrease ->pc_buf size to 64 bytes.

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

* Move ide_map_sg() calls out from ide_build_sglist()
  to ide_dma_prepare().

* Pass command to ide_destroy_dmatable().

* Rename ide_build_sglist() to ide_dma_map_sg()
  and ide_destroy_dmatable() to ide_dma_unmap_sg().

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

* Add (an optional) ->dma_check method for checking if DMA can be
  used for a given command and fail DMA setup in ide_dma_prepare()
  if necessary.

* Convert alim15x3 and trm290 host drivers to use ->dma_check.

* Rename ali15x3_dma_setup() to ali_dma_check() while at it.

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

* Add ide_dma_prepare() helper.

* Convert ide_issue_pc() and do_rw_taskfile() to use it.

* Make ide_build_sglist() static.

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

Move ide_destroy_dmatable() call out from ->dma_end method to
{ide_pc,cdrom_newpc,ide_dma}_intr(), ide_dma_timeout_retry()
and sgiioc4_resetproc().

This causes minor/safe behavior changes w.r.t.:
* cmd64x.c::cmd64{8,x}_dma_end()
* cs5536.c::cs5536_dma_end()
* icside.c::icside_dma_end()
* it821x.c::it821x_dma_end()
* scc_pata.c::__scc_dma_end()
* sl82c105.c::sl82c105_dma_end()
* tx4939ide.c::tx4939ide_dma_end()

v2:
* Fix build for CONFIG_BLK_DEV_IDEDMA=n (reported by Randy Dunlap).

Cc: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: NSergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>

All custom ->dma_timeout implementations call the generic one thus it is
possible to have only an optional method for resetting DMA engine instead:

* Add ->dma_clear method and convert hpt366, pdc202xx_old and sl82c105
  host drivers to use it.

* Always use ide_dma_timeout() in ide_dma_timeout_retry() and remove
 ->dma_timeout method.

* Make ide_dma_timeout() static.

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

We now support arbitrary number of bytes per-IRQ also for fs requests
so remove ide_cd_check_transfer_size() and IDE_AFLAG_LIMIT_NFRAMES.

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

* Export ide_pio_bytes().

* Add ->last_xfer_len field to struct ide_cmd.

* Add ide_cd_error_cmd() helper to ide-cd.

* Convert ide-cd to use scatterlists also for PIO transfers (fs requests
  only for now) and get rid of partial completions (except when the error
  happens -- which is still subject to change later because looking at
  ATAPI spec it seems that the device is free to error the whole transfer
  with setting the Error bit only on the last transfer chunk).

* Update ide_cd_{prepare_rw,restore_request,do_request}() accordingly.

* Inline ide_cd_restore_request() into cdrom_start_rw().

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

* Pass number of bytes instead of sectors to ide_init_sg_cmd().

* Pass number of bytes to process to ide_pio_sector() and rename
  it to ide_pio_bytes().

* Rename ->nsect field to ->nbytes in struct ide_cmd and use
  ->nbytes, ->nleft and ->cursg_ofs to keep track of number of
  bytes instead of sectors.

There should be no functional changes caused by this patch.
Acked-by: NBorislav Petkov <petkovbb@gmail.com>
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>

* Pass command structure to ide_execute_command() and skip
  __ide_set_handler() for ATAPI protocols on non-DRQ devices.

* Convert ide_issue_pc() to always use ide_execute_command()
  and remove no longer needed ide_execute_pkt_cmd().

v2:
* Fix for non-DRQ devices (based on report from Borislav).

There should be no functional changes caused by this patch.
Acked-by: NBorislav Petkov <petkovbb@gmail.com>
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>

* Rename dma_timer_expiry() to ide_dma_sff_timer_expiry() and export it.

* Add ->dma_timer_expiry method and use it to set hwif->expiry for
  ATA_PROT_DMA protocol in do_rw_taskfile().

* Initialize ->dma_timer_expiry to ide_dma_sff_timer_expiry() for SFF hosts.

* Move setting hwif->expiry from ide_execute_command() to its users and drop
  'expiry' argument.

* Use ide_execute_command() instead of ->dma_exec_cmd in do_rw_taskfile().

* Remove ->dma_exec_cmd method and its implementations.

* Unexport ide_execute_command() and ide_dma_intr().

v2:
* Fix CONFIG_BLK_DEV_IDEDMA=n build (noticed by Randy Dunlap).

* Fix *dma_expiry naming (suggested by Sergei Shtylyov).

There should be no functional changes caused by this patch.

Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>

* Set hwif->expiry prior to calling [__]ide_set_handler()
  and drop 'expiry' argument.

* Set hwif->expiry to NULL in ide_{timer_expiry,intr}()
  and remove 'hwif->expiry = NULL' assignments.

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

* Pass command to ide_issue_pc() and update ->do_request methods
  in ide-{cd,floppy,tape}.c accordingly.

* Convert ide_pktcmd_tf_load() to ide_init_packet_cmd() which
  just initializes command structure and use do_rw_taskfile()
  to load ATA_CMD_PACKET commands.

While at it:

* Rename ide{floppy,tape}_issue_pc() to ide_{floppy,tape}_issue_pc().

There should be no functional changes caused by this patch.
Acked-by: NBorislav Petkov <petkovbb@gmail.com>
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>

* Set IDE_TFLAG_WRITE flag and ->rq also for ATA_CMD_PACKET
  commands.

* Pass command to ->dma_setup method and update all its
  implementations accordingly.

* Pass command instead of request to ide_build_sglist(),
  *_build_dmatable() and ide_map_sg().

While at it:

* Fix scc_dma_setup() documentation + use ATA_DMA_WR define.

* Rename sgiioc4_build_dma_table() to sgiioc4_build_dmatable(),
  change return value type to 'int' and drop unused 'ddir'
  argument.

* Do some minor cleanups in [tx4939]ide_dma_setup().

There should be no functional changes caused by this patch.
Acked-by: NBorislav Petkov <petkovbb@gmail.com>
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>

* Add ide_rq_bytes() helper.

* Add blk_noretry_request() quirk to ide_complete_rq() (currently only fs
  requests can be marked as "noretry" so there is no change in behavior).

* Switch current ide_end_request() users to use ide_complete_rq().

  [ No need to check for rq->nr_sectors == 0 in {ide_dma,task_pio}_intr(),
    nsectors == 0 in cdrom_end_request() and err == 0 in ide_do_devset(). ]

* Remove no longer needed ide_end_request().

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

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

It is no longer needed so remove it, also while at it dequeue the request
only on blk_end_request() success and make ide_complete_rq() return an error
value.
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Set rq->errors at ide_complete_rq() call sites and then pass
error value to ide_complete_rq().

[ Some rq->errors assignments look really wrong but this patch
  leaves them alone to not introduce too many changes at once. ]

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

* Move request dequeuing from __ide_end_request() to ide_end_request().

* Rename __ide_end_request() to ide_end_rq() and export it.

* Fix ide_end_rq() to pass original blk_end_request() return value.

* ide_end_dequeued_request() is used only in cdrom_end_request()
  so inline it there and then remove the function.

v2:
* Remove needless BUG_ON() while at it (start_request()'s one is enough).

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

* Add IDE_TFLAG_MULTI_PIO taskfile flag and set it for commands
  using multi-PIO protocol.

* Use ata_tf_protocols enums instead of TASKFILE_* defines to
  denote command's protocol and then rename ->data_phase field
  to ->protocol.

* Remove no longer needed <linux/hdreg.h> includes.

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

* Move command related fields from ide_hwif_t to struct ide_cmd.

* Make ide_init_sg_cmd() take command and sectors number as arguments.

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

* Add IDE_TFLAG_FS taskfile flag and set it for REQ_TYPE_FS requests.

* Convert ->{in,out}put_data methods to take command instead of request
  as an argument.  Then convert pre_task_out_intr(), task_end_request(),
  task_error(), task_in_unexpected(), ide_pio_sector(), ide_pio_multi()
  and ide_pio_datablock() in similar way.

* Rename task_end_request() to ide_finish_cmd().

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

While at it:
- rename struct ide_task_s to struct ide_cmd
- remove stale comments from idedisk_{read_native,set}_max_address()
- drop unused 'cmd' argument from ide_{cmd,task}_ioctl()
- drop unused 'task' argument from tx4939ide_tf_load_fixup()
- rename ide_complete_task() to ide_complete_cmd()
- use consistent naming for struct ide_cmd variables

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

* Re-map sg table if needed in ide_build_sglist().

* Move ide_build_sglist() call from ->dma_setup to its users.

* Un-export ide_build_sglist().

v2:
* Build fix for CONFIG_BLK_DEV_IDEDMA=n (noticed by Randy Dunlap).

There should be no functional changes caused by this patch.

Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Make ->pc_callback method return request status and then move
the request completion from ->pc_callback to ide_pc_intr().

There should be no functional changes caused by this patch.
Acked-by: NBorislav Petkov <petkovbb@gmail.com>
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>

* Handle completion of private driver requests explicitly
  for ide_floppy and ide_tape media in ide_kill_rq().

* Remove no longer needed ->end_request method.

There should be no functional changes caused by this patch.
Acked-by: NBorislav Petkov <petkovbb@gmail.com>
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>