Commit Graph

84 Commits

Author SHA1 Message Date
Axel Lin 2fc75da0c5 ata: use module_pci_driver
This patch converts the drivers in drivers/ata/* to use module_pci_driver()
macro which makes the code smaller and a bit simpler.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Jeff Garzik <jgarzik@pobox.com>
Cc: Mikael Pettersson <mikpe@it.uu.se>
Cc: Mark Lord <kernel@teksavvy.com>
Cc: Jeremy Higdon <jeremy@sgi.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2012-07-25 15:12:11 -04:00
Joe Perches 06296a1e68 ata: Add and use ata_print_version_once
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: Joe Perches <joe@perches.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
2011-07-23 17:57:36 -04:00
Joe Perches a44fec1fce ata: Convert dev_printk(KERN_<LEVEL> to dev_<level>(
Saves a bit of text as the call takes fewer args.

Coalesce a few formats.
Convert a few bare printks to pr_cont.

$ size drivers/ata/built-in.o*
   text	   data	    bss	    dec	    hex	filename
 558429	  73893	 117864	 750186	  b726a	drivers/ata/built-in.o.allyesconfig.new
 559574	  73893	 117888	 751355	  b76fb	drivers/ata/built-in.o.allyesconfig.old
 149567	  14689	   4220	 168476	  2921c	drivers/ata/built-in.o.defconfig.new
 149851	  14689	   4220	 168760	  29338	drivers/ata/built-in.o.defconfig.old

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
2011-07-23 17:57:36 -04:00
Sergei Shtylyov 9cbe056f6c libata: remove ATA_FLAG_NO_LEGACY
All checks of ATA_FLAG_NO_LEGACY have been removed by the commits
c791c30670 ([libata] minor PCI IDE probe
fixes and cleanups) and f0d36efdc6 (libata:
update libata core layer to use devres), so I think it's time to finally
get rid of this flag...

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2011-03-02 02:36:46 -05:00
Sergei Shtylyov 3696df3099 libata: remove ATA_FLAG_MMIO
Commit 0d5ff56677 (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: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2011-03-02 02:36:46 -05:00
Tejun Heo f60d70113f libata-sff: prd is BMDMA specific
struct ata_prd and ap->prd are BMDMA specific.  Add bmdma_ prefix to
them and move them inside CONFIG_ATA_SFF.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2010-05-19 13:38:54 -04:00
Tejun Heo fe06e5f9b7 libata-sff: separate out BMDMA EH
Some of error handling logic in ata_sff_error_handler() and all of
ata_sff_post_internal_cmd() are for BMDMA.  Create
ata_bmdma_error_handler() and ata_bmdma_post_internal_cmd() and move
BMDMA part into those.

While at it, change DMA protocol check to ata_is_dma(), fix
post_internal_cmd to call ap->ops->bmdma_stop instead of directly
calling ata_bmdma_stop() and open code hardreset selection so that
ata_std_error_handler() doesn't have to know about sff hardreset.

As these two functions are BMDMA specific, there's no reason to check
for bmdma_addr before calling bmdma methods if the protocol of the
failed command is DMA.  sata_mv and pata_mpc52xx now don't need to set
.post_internal_cmd to ATA_OP_NULL and pata_icside and sata_qstor don't
need to set it to their bmdma_stop routines.

ata_sff_post_internal_cmd() becomes noop and is removed.

This fixes p3 described in clean-up-BMDMA-initialization patch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2010-05-19 13:36:46 -04:00
Tejun Heo c7087652e1 libata-sff: clean up BMDMA initialization
When BMDMA initialization failed or BMDMA was not available for
whatever reason, bmdma_addr was left at zero and used as an indication
that BMDMA shouldn't be used.  This leads to the following problems.

p1. For BMDMA drivers which don't use traditional BMDMA register,
    ata_bmdma_mode_filter() incorrectly inhibits DMA modes.  Those
    drivers either have to inherit from ata_sff_port_ops or clear
    ->mode_filter explicitly.

p2. non-BMDMA drivers call into BMDMA PRD table allocation.  It
    doesn't actually allocate PRD table if bmdma_addr is not
    initialized but is still confusing.

p3. For BMDMA drivers which don't use traditional BMDMA register, some
    methods might not be invoked as expected (e.g. bmdma_stop from
    ata_sff_post_internal_cmd()).

p4. SFF drivers w/ custom DMA interface implement noop BMDMA ops
    worrying libata core might call into one of them.

These problems are caused by the muddy line between SFF and BMDMA and
the assumption that all BMDMA controllers initialize bmdma_addr.

This patch fixes p1 and p2 by removing the bmdma_addr assumption and
moving prd allocation to BMDMA port start.  Later patches will fix the
remaining issues.

This patch improves BMDMA initialization such that

* When BMDMA register initialization fails, falls back to PIO instead
  of failing.  ata_pci_bmdma_init() never fails now.

* When ata_pci_bmdma_init() falls back to PIO, it clears
  ap->mwdma_mask and udma_mask instead of depending on
  ata_bmdma_mode_filter().  This makes ata_bmdma_mode_filter()
  unnecessary thus resolving p1.

* ata_port_start() which actually is BMDMA specific is moved to
  ata_bmdma_port_start().  ata_port_start() and ata_sff_port_start()
  are killed.

* ata_sff_port_start32() is moved and renamed to
  ata_bmdma_port_start32().

Drivers which no longer call into PRD table allocation are...

  pdc_adma, sata_inic162x, sata_qstor, sata_sx4, pata_cmd640 and all
  drivers which inherit from ata_sff_port_ops.

pata_icside sets ->port_start to ATA_OP_NULL as it doesn't need PRD
but is a BMDMA controller and doesn't have custom port_start like
other such controllers.

Note that with the previous patch which makes all and only BMDMA
drivers inherit from ata_bmdma_port_ops, this change doesn't break
drivers which need PRD table.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2010-05-19 13:32:19 -04:00
Tejun Heo 3e4ec3443f libata: kill ATA_FLAG_DISABLED
ATA_FLAG_DISABLED is only used by drivers which don't use
->error_handler framework and is largely broken.  Its only meaningful
function is to make irq handlers skip processing if the flag is set,
which is largely useless and even harmful as it makes those ports more
likely to cause IRQ storms.

Kill ATA_FLAG_DISABLED and makes the callers disable attached devices
instead.  ata_port_probe() and ata_port_disable() which manipulate the
flag are also killed.

This simplifies condition check in IRQ handlers.  While updating IRQ
handlers, remove ap NULL check as libata guarantees consecutive port
allocation (unoccupied ports are initialized with dummies) and
long-obsolete ATA_QCFLAG_ACTIVE check (checked by ata_qc_from_tag()).

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2010-05-17 22:49:02 -04:00
Tejun Heo 5a0e3ad6af include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-30 22:02:32 +09:00
Mikael Pettersson a2342f4643 sata_promise: don't classify overruns as HSM errors
When sata_promise encounters an overrun or underrun error it
translates that to a libata AC_ERR_HSM, causing a hard reset.
Since over/under-runs were thought to be rare and transient,
this action seemed reasonable.

Unfortunately it turns out that the controller throws overrun
errors when e.g. hal polls a CD or DVD writer containing blank
media, causing long sequences of hard resets and retries before
EH finally gives up.

This patch updates sata_promise to classify over/under-runs as
AC_ERR_OTHER instead. This allows libata EH and upper layers to
retry or fail the operation as they see fit without the disruption
caused by repeated hard resets.

This fixes a problem using a DVD-RAM drive with sata_promise,
reported by Thomas Schorpp. I also tested it on a DVD-RW drive.

Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
Tested-by: thomas schorpp <thomas.schorpp@googlemail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2010-01-12 14:33:07 -05:00
Mikael Pettersson ff7cddf59e sata_promise: update reset code
sata_promise's reset code has deviated quite a bit from
the Promise reference driver's, and it has been observed
to fail to recover from errors in some cases.

This patch thus updates the reset code to more closely
match the reference driver:

- soft reset (pdc_reset_port):
  * wait for ATA engine to not be in packet command mode
    (2nd gen only)
  * write reset bit in PDC_CTLSTAT before the first read
    in the loop
  * for 2nd gen SATA follow up with FPDMA reset and clearing
    error status registers
- hard reset (pdc_sata_hardreset):
  * wait for ATA engine to not be in packet command mode
    (2nd gen only)
  * reset ATA engine via the PCI control register
  * Tejun's change to use non-waiting hardreset + follow-up SRST

I'm not changing the hotplug mask bits since they are taken care
of by sata_promise's ->freeze() and ->thaw() operations. And I'm
not writing the PMP port # because that's always zero (for now).

Tested here on various controllers. In particular, one disk
which used to timeout and fail to recover from certain hdparm
and smartmonctl commands now works nicely.

Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2009-09-17 16:46:34 -04:00
Mikael Pettersson 0ae6654da4 sata_promise: disable hotplug on 1st gen chips
1st generation Promise SATA chips are prone to generating spurious
hotplug events which can disrupt normal operation. This has been
observed on 20376 and 20378 chips. This patch thus disables hotplug
support on 1st gen chips while leaving it enabled for 2nd gen chips.

The pdc_sata_hotplug_offset() function becomes redundant so it is
removed.

Tested on 1st gen 20376 and 20378 mainboard chips and on a 2nd gen
SATA300 PCI card.

Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
Tested-by: Kurt Roeckx <kurt@roeckx.be>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2009-09-17 16:46:12 -04:00
Alan Cox c96f1732e2 [libata] Improve timeout handling
On a timeout call a device specific handler early in the recovery so that
we can complete and process successful commands which timed out due to IRQ
loss or the like rather more elegantly.

[Revised to exclude the timeout handling on a few devices that inherit from
 SFF but are not SFF enough to use the default timeout handler]

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2009-03-24 22:52:39 -04:00
Erik Inge Bolsø 14bdef982c [libata] convert drivers to use ata.h mode mask defines
No functional changes in this patch.

Signed-off-by: Erik Inge Bolsø <knan-lkml@anduin.net>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2009-03-24 22:13:27 -04:00
Mikael Pettersson cadef677e4 sata_promise: add ATA engine reset to reset ops
Promise ATA engines need to be reset when errors occur.
That's currently done for errors detected by sata_promise itself,
but it's not done for errors like timeouts detected outside of
the low-level driver.

The effect of this omission is that a timeout tends to result
in a sequence of failed COMRESETs after which libata EH gives
up and disables the port. At that point the port's ATA engine
hangs and even reloading the driver will not resume it.

To fix this, make sata_promise override ->hardreset on SATA
ports with code which calls pdc_reset_port() on the port in
question before calling libata's hardreset. PATA ports don't
use ->hardreset, so for those we override ->softreset instead.

Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2008-11-04 01:08:03 -05:00
Tejun Heo 82ef04fb4c libata: make SCR access ops per-link
Logically, SCR access ops should take @link; however, there was no
compelling reason to convert all SCR access ops when adding @link
abstraction as there's one-to-one mapping between a port and a non-PMP
link.  However, that assumption won't hold anymore with the scheduled
addition of slave link.

Make SCR access ops per-link.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2008-09-29 00:22:28 -04:00
Mikael Pettersson 7715a6f9cd sata_promise: other cleanups
Minor coding-style fixes for sata_promise:
- remove stray blank lines
- fix checkpatch.pl errors; warnings about long lines
  remain, but I don't intend to address those at this time
- remove two inline directives: neither is essential and
  both functions are trivially inlinable anyway by virtue
  of being static and having a single unique call site
- fix comment in pdc_interrupt(): the bits in PDC_INT_SEQMASK
  denote SEQIDs not tags, the distinction becomes important
  when NCQ gets implemented

Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2008-05-19 17:31:34 -04:00
Mikael Pettersson 821d22cdcd sata_promise: mmio access cleanups
This patch cleans up sata_promise's mmio accesses.

In sata_promise there are three distinct mmio address spaces:
1. global registers, offsets from host->iomap[PDC_MMIO_BAR]
2. per-port ATA registers, offsets from ap->ioaddr.cmd_addr
3. per-port SATA registers, offsets from ap->ioaddr.scr_addr

The driver currently often fails to indicate which address space
a given mmio base pointer refers to, which is a source of bugs
and confusion (see recent pdc_thaw() irq clearing bug; it's also
been an obstacle for the pending NCQ extensions).

To reduce these problems, adopt a coding style where the name of
a base pointer always indicates which address space it refers to:
1. global registers: host_mmio
2. per-port ATA registers: ata_mmio
3. per-port SATA registers: sata_mmio

Also rearrange register offset definitions to clearly indicate
which address space they belong to, and add a symbolic definition
for the previously hard-coded PHYMODE4 register.

Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2008-05-19 17:31:26 -04:00
Mikael Pettersson a13db78e22 sata_promise: fix irq clearing buglets
This patch fixes two bugs in sata_promise's irq status clearing paths:
1. When clearing the irq status for a specific port, the driver
   read the global SEQMASK register. This is wrong because that
   clears the irq status for _all_ ports.
2. pdc_thaw() incorrectly added the PDC_INT_SEQMASK host register
   offset to a per-port ata engine base address. This resulted in
   it reading the unrelated PDC_PKT_SUBMIT register, which did not
   have the desired irq status clearing effect.

In both cases the fix is to read from the port's Command/Status
register. This also matches what Promise's own driver does.

Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2008-05-19 17:30:47 -04:00
Tejun Heo 5682ed33aa libata: rename SFF port ops
Add sff_ prefix to SFF specific port ops.

This rename is in preparation of separating SFF support out of libata
core layer.  This patch strictly renames ops and doesn't introduce any
behavior difference.

Signed-off-by: Tejun Heo <htejun@gmail.com>
2008-04-17 15:44:22 -04:00
Tejun Heo 9363c3825e libata: rename SFF functions
SFF functions have confusing names.  Some have sff prefix, some have
bmdma, some std, some pci and some none.  Unify the naming by...

* SFF functions which are common to both BMDMA and non-BMDMA are
  prefixed with ata_sff_.

* SFF functions which are specific to BMDMA are prefixed with
  ata_bmdma_.

* SFF functions which are specific to PCI but apply to both BMDMA and
  non-BMDMA are prefixed with ata_pci_sff_.

* SFF functions which are specific to PCI and BMDMA are prefixed with
  ata_pci_bmdma_.

* Drop generic prefixes from LLD specific routines.  For example,
  bfin_std_dev_select -> bfin_dev_select.

The following renames are noteworthy.

  ata_qc_issue_prot() -> ata_sff_qc_issue()
  ata_pci_default_filter() -> ata_bmdma_mode_filter()
  ata_dev_try_classify() -> ata_sff_dev_classify()

This rename is in preparation of separating SFF support out of libata
core layer.  This patch strictly renames functions and doesn't
introduce any behavior difference.

Signed-off-by: Tejun Heo <htejun@gmail.com>
2008-04-17 15:44:21 -04:00
Al Viro 826cd156de libata annotations
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2008-04-17 15:44:20 -04:00
Tejun Heo a1efdaba2d libata: make reset related methods proper port operations
Currently reset methods are not specified directly in the
ata_port_operations table.  If a LLD wants to use custom reset
methods, it should construct and use a error_handler which uses those
reset methods.  It's done this way for two reasons.

First, the ops table already contained too many methods and adding
four more of them would noticeably increase the amount of necessary
boilerplate code all over low level drivers.

Second, as ->error_handler uses those reset methods, it can get
confusing.  ie. By overriding ->error_handler, those reset ops can be
made useless making layering a bit hazy.

Now that ops table uses inheritance, the first problem doesn't exist
anymore.  The second isn't completely solved but is relieved by
providing default values - most drivers can just override what it has
implemented and don't have to concern itself about higher level
callbacks.  In fact, there currently is no driver which actually
modifies error handling behavior.  Drivers which override
->error_handler just wraps the standard error handler only to prepare
the controller for EH.  I don't think making ops layering strict has
any noticeable benefit.

This patch makes ->prereset, ->softreset, ->hardreset, ->postreset and
their PMP counterparts propoer ops.  Default ops are provided in the
base ops tables and drivers are converted to override individual reset
methods instead of creating custom error_handler.

* ata_std_error_handler() doesn't use sata_std_hardreset() if SCRs
  aren't accessible.  sata_promise doesn't need to use separate
  error_handlers for PATA and SATA anymore.

* softreset is broken for sata_inic162x and sata_sx4.  As libata now
  always prefers hardreset, this doesn't really matter but the ops are
  forced to NULL using ATA_OP_NULL for documentation purpose.

* pata_hpt374 needs to use different prereset for the first and second
  PCI functions.  This used to be done by branching from
  hpt374_error_handler().  The proper way to do this is to use
  separate ops and port_info tables for each function.  Converted.

Signed-off-by: Tejun Heo <htejun@gmail.com>
2008-04-17 15:44:18 -04:00
Tejun Heo 029cfd6b74 libata: implement and use ops inheritance
libata lets low level drivers build ata_port_operations table and
register it with libata core layer.  This allows low level drivers
high level of flexibility but also burdens them with lots of
boilerplate entries.

This becomes worse for drivers which support related similar
controllers which differ slightly.  They share most of the operations
except for a few.  However, the driver still needs to list all
operations for each variant.  This results in large number of
duplicate entries, which is not only inefficient but also error-prone
as it becomes very difficult to tell what the actual differences are.

This duplicate boilerplates all over the low level drivers also make
updating the core layer exteremely difficult and error-prone.  When
compounded with multi-branched development model, it ends up
accumulating inconsistencies over time.  Some of those inconsistencies
cause immediate problems and fixed.  Others just remain there dormant
making maintenance increasingly difficult.

To rectify the problem, this patch implements ata_port_operations
inheritance.  To allow LLDs to easily re-use their own ops tables
overriding only specific methods, this patch implements poor man's
class inheritance.  An ops table has ->inherits field which can be set
to any ops table as long as it doesn't create a loop.  When the host
is started, the inheritance chain is followed and any operation which
isn't specified is taken from the nearest ancestor which has it
specified.  This operation is called finalization and done only once
per an ops table and the LLD doesn't have to do anything special about
it other than making the ops table non-const such that libata can
update it.

libata provides four base ops tables lower drivers can inherit from -
base, sata, pmp, sff and bmdma.  To avoid overriding these ops
accidentaly, these ops are declared const and LLDs should always
inherit these instead of using them directly.

After finalization, all the ops table are identical before and after
the patch except for setting .irq_handler to ata_interrupt in drivers
which didn't use to.  The .irq_handler doesn't have any actual effect
and the field will soon be removed by later patch.

* sata_sx4 is still using old style EH and currently doesn't take
  advantage of ops inheritance.

Signed-off-by: Tejun Heo <htejun@gmail.com>
2008-04-17 15:44:17 -04:00