It supports VX855 and future chips whose IDE controller uses PCI ID 0x0571.
Signed-off-by: Joseph Chan <josephchan@via.com.tw>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Commit bfce5e0179 implemented custom
tf_load for pata_via. This patch cleans it up a bit.
* Instead of duplicating whole body, copy tf and set ATA_TFLAG_DEVICE
when necessary.
* Rename via_ata_tf_load() to via_tf_load().
* No need to set .tf_load in via_port_ops_noirq as it inherits from
via_port_ops.
* Clean up indentation.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Joseph Chan <JosephChan@via.com.tw>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Add flag VIA_SATA_PATA for vx800, VX800 uses the same
chipset(0x0581/0x5324) as CX700, which has 1 PATA channel(Master/Slave)
and 1 SATA channel(Master/Slave) Add function <via_ata_tf_load>. This is
to fix the internal bug of VIA chipsets, which will reset the device
register after changing the IEN bit in CTL register
Signed-off-by: Joseph Chan <josephchan@via.com.tw>
Cc: Tejun Heo <tj@kernel.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Use the kernel-provided clamp_val() macro.
FIT was always applied to a member of struct ata_timing (unsigned short)
and two constants. clamp_val will not cast to short anymore.
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: Tejun Heo <htejun@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
The discrete VIA ATA chips don't have 0x40 enable bits. We check that
properly in one location but not another. This causes some users 6410
RAID cards to be incorrectly skipped.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
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>
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>
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>
port_info->private_data is currently used for two purposes - to record
private data about the port_info or to specify host->private_data to
use when allocating ata_host.
This overloading is confusing and counter-intuitive in that
port_info->private_data becomes host->private_data instead of
port->private_data. In addition, port_info and host don't correspond
to each other 1-to-1. Currently, the first non-NULL
port_info->private_data is used.
This patch makes port_info->private_data just be what it is -
private_data for the port_info where LLD can jot down extra info.
libata no longer sets host->private_data to the first non-NULL
port_info->private_data, @host_priv argument is added to
ata_pci_init_one() instead. LLDs which use ata_pci_init_one() can use
this argument to pass in pointer to host private data. LLDs which
don't should use init-register model anyway and can initialize
host->private_data directly.
Adding @host_priv instead of using init-register model for LLDs which
use ata_pci_init_one() is suggested by Alan Cox.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
ata_pci_init_one() is the only function which uses ops->irq_handler
and pi->sht. Other initialization functions take the same information
as arguments. This causes confusion and duplicate unused entries in
structures.
Make ata_pci_init_one() take sht as an argument and use ata_interrupt
implicitly. All current users use ata_interrupt and if different irq
handler is necessary open coding ata_pci_init_one() using
ata_prepare_sff_host() and ata_activate_sff_host can be done under ten
lines including error handling and driver which requires custom
interrupt handler is likely to require custom initialization anyway.
As ata_pci_init_one() was the last user of ops->irq_handler, this
patch also kills the field.
Signed-off-by: Tejun Heo <htejun@gmail.com>
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>
libata lets low level drivers build scsi_host_template and register it
to the SCSI layer. This allows low level drivers high level of
flexibility but also burdens them with lots of boilerplate entries.
This patch implements SHT initializers which can be used to initialize
all the boilerplate entries in a sht. Three variants of them are
implemented - BASE, BMDMA and NCQ - for different types of drivers.
Note that entries can be overriden by putting individual initializers
after the helper macro.
All sht tables are identical before and after this patch.
Signed-off-by: Tejun Heo <htejun@gmail.com>
PCI device should be powered up or powered up before its PCI regsiters
are accessed. Although PCI configuration register access is allowed
in D3hot, PCI device is free to reset its status when transiting from
D3hot to D0 causing configuration data to change.
Many libata SFF drivers which use ata_pci_init_one() read and update
configuration registers before calling ata_pci_init_one() which
enables the PCI device. Also, in resume paths, some drivers access
registers without resuming the PCI device.
This patch adds a call to pcim_enable_device() in init path if
register is accessed before calling ata_pci_init_one() and make resume
paths first resume PCI devices, access PCI configuration regiters then
resume ATA host.
While at it...
* cmd640 was strange in that it set ->resume even when CONFIG_PM is
not. This is by-product of minimal build fix. Updated.
* In cs5530, Don't BUG() on reinit failure. Just whine and fail
resume.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Reimplement ata_acpi_cbl_80wire() using ata_acpi_gtm_xfermask() and
while at it relocate the function below ata_acpi_gtm_xfermask().
New ata_acpi_cbl_80wire() implementation takes @gtm, in both pata_via
and pata_amd, use the initial GTM value. Both are trying to peek
initial BIOS configuration, so using initial caching value makes
sense. This fixes ACPI part of cable detection in pata_amd which
previously always returned 0 because configuring PIO0 during reset
clears DMA configuration.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
* Don't program UDMA timings when programming PIO or MWDMA modes.
This has also a nice side-effect of fixing regression added by commit
681c80b5d9 ("libata: correct handling of
SRST reset sequences") (->set_piomode method for PIO0 is called before
->cable_detect method which checks UDMA timings to get the cable type).
* Bump driver version.
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Tested-by: "Thomas Lindroth" <thomas.lindroth@gmail.com>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Tejun Heo <htejun@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Fix the various misspellings of "system", controller", "interrupt" and
"[un]necessary".
Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
This avoids allocating DMA buffers if not needed but at the moment is
mostly just a neatness item.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
It was always set to ata_port_disable(). Removed the hook, and replaced
the very few ap->ops->port_disable() callsites with direct calls to
ata_port_disable().
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Testing this on the VIA boards fixes several problems with otherwise
undetectable SATA bridge chips
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
* ->irq_ack() is redundant to what the irq handler already
performs... chk-status + irq-clear. Furthermore, it is only
called in one place, when screaming-irq-debugging is enabled,
so we don't want to bother with a hook just for that.
* ata_dummy_irq_on() is only ever used in drivers that have
no callpath reaching ->irq_on(). Remove .irq_on hook from
those drivers, and the now-unused ata_dummy_irq_on()
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Make reset methods and related functions deal with ata_link instead of
ata_port.
* ata_do_reset()
* ata_eh_reset()
* all prereset/reset/postreset methods and related functions
This patch introduces no behavior change.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Three main sets of changes:
1) dmi_get_system_info() return value should have been marked const,
since callers should not be changing that data.
2) const-ify DMI internals, since DMI firmware tables should,
whenever possible, be marked const to ensure we never ever write to
that data area.
3) const-ify DMI API, to enable marking tables const where possible
in low-level drivers.
And if we're really lucky, this might enable some additional
optimizations on the part of the compiler.
The bulk of the changes are #2 and #3, which are interrelated. #1 could
have been a separate patch, but it was so small compared to the others,
it was easier to roll it into this changeset.
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
More cable funnies
Signed-off-by: Alan Cox <alan@redhat.com>
Tested-by: Mikael Pettersson <mikpe@it.uu.se>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Instead of all drivers reading pci config space to get the revision
ID, they can now use the pci_device->revision member.
This exposes some issues where drivers where reading a word or a dword
for the revision number, and adding useless error-handling around the
read. Some drivers even just read it for no purpose of all.
In devices where the revision ID is being copied over and used in what
appears to be the equivalent of hotpath, I have left the copy code
and the cached copy as not to influence the driver's performance.
Compile tested with make all{yes,mod}config on x86_64 and i386.
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Acked-by: Dave Jones <davej@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The ATA_UDMAx masks are self-documenting, and far better than manually
writing in the hex mask.
Note that pata_it8213 mask differed from the comment. Added a FIXME there.
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Several people have reported LITE-ON LTR-48246S detection failed
because SETXFER fails. It seems the device raises IRQ too early after
SETXFER. This is controller independent. The same problem has been
reported for different controllers.
So, now we have pata_via where the controller raises IRQ before it's
ready after SETXFER and a device which does similar thing. This patch
makes libata always execute SETXFER via polling. As this only happens
during EH, performance impact is nil. Setting ATA_TFLAG_POLLING is
also moved from issue hot path to ata_dev_set_xfermode() - the only
place where SETXFER can be issued.
Note that ATA_TFLAG_POLLING applies only to drivers which implement
SFF TF interface and use libata HSM. More advanced controllers ignore
the flag. This doesn't matter for this fix as SFF TF controllers are
the problematic ones.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Supplied by VIA.
Also, convert named constants to hex values in the pata_via
PCI ID table. (standard libata policy for PCI device IDs, which are
considered simply arbitrary hex numbers, without a need to create a
single-use constant in linux/pci_ids.h)
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Oh the joy of saving a fraction of a cent using short 40 wire cables and
not faking 80wire
Teach the VIA driver that there are some systems we need to know are
magically wired for high speeds.
Signed-off-by: Alan Cox <alan@redhat.com>
Tested-by: Francis Russell <FrancisRussell@btinternet.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
The intention of using port_mask in SFF init helpers was to eventually
support exoctic configurations such as combination of legacy and
native port on the same controller. This never became actually
necessary and the related code always has been subtly broken one way
or the other. Now that new init model is in place, there is no reason
to make common helpers capable of handling all corner cases. Exotic
cases can simply dealt within LLDs as necessary.
This patch removes port_mask handling in SFF init helpers. SFF init
helpers don't take n_ports argument and interpret it into port_mask
anymore. All information is carried via port_info. n_ports argument
is dropped and always two ports are allocated. LLD can tell SFF to
skip certain port by marking it dummy. Note that SFF code has been
treating unuvailable ports this way for a long time until recent
breakage fix from Linus and is consistent with how other drivers
handle with unavailable ports.
This fixes 1-port legacy host handling still broken after the recent
native mode fix and simplifies SFF init logic. The following changes
are made...
* ata_pci_init_native_host() and ata_init_legacy_host() both now try
to initialized whatever they can and mark failed ports dummy. They
return 0 if any port is successfully initialized.
* ata_pci_prepare_native_host() and ata_pci_init_one() now doesn't
take n_ports argument. All info should be specified via port_info
array. Always two ports are allocated.
* ata_pci_init_bmdma() exported to be used by LLDs in exotic cases.
* port_info handling in all LLDs are standardized - all port_info
arrays are const stack variable named ppi. Unless the second port
is different from the first, its port_info is specified as NULL
(tells libata that it's identical to the last non-NULL port_info).
* pata_hpt37x/hpt3x2n: don't modify static variable directly. Make an
on-stack copy instead as ata_piix does.
* pata_uli: It has 4 ports instead of 2. Don't use
ata_pci_prepare_native_host(). Allocate the host explicitly and use
init helpers. It's simple enough.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Reimplement suspend/resume support using sdev->manage_start_stop.
* Device suspend/resume is now SCSI layer's responsibility and the
code is simplified a lot.
* DPM is dropped. This also simplifies code a lot. Suspend/resume
status is port-wide now.
* ata_scsi_device_suspend/resume() and ata_dev_ready() removed.
* Resume now has to wait for disk to spin up before proceeding. I
couldn't find easy way out as libata is in EH waiting for the
disk to be ready and sd is waiting for EH to complete to issue
START_STOP.
* sdev->manage_start_stop is set to 1 in ata_scsi_slave_config().
This fixes spindown on shutdown and suspend-to-disk.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Add @deadline to prereset and reset methods and make them honor it.
ata_wait_ready() which directly takes @deadline is implemented to be
used as the wait function. This patch is in preparation for EH timing
improvements.
* ata_wait_ready() never does busy sleep. It's only used from EH and
no wait in EH is that urgent. This function also prints 'be
patient' message automatically after 5 secs of waiting if more than
3 secs is remaining till deadline.
* ata_bus_post_reset() now fails with error code if any of its wait
fails. This is important because earlier reset tries will have
shorter timeout than the spec requires. If a device fails to
respond before the short timeout, reset should be retried with
longer timeout rather than silently ignoring the device.
There are three behavior differences.
1. Timeout is applied to both devices at once, not separately. This
is more consistent with what the spec says.
2. When a device passes devchk but fails to become ready before
deadline. Previouly, post_reset would just succeed and let
device classification remove the device. New code fails the
reset thus causing reset retry. After a few times, EH will give
up disabling the port.
3. When slave device passes devchk but fails to become accessible
(TF-wise) after reset. Original code disables dev1 after 30s
timeout and continues as if the device doesn't exist, while the
patched code fails reset. When this happens, new code fails
reset on whole port rather than proceeding with only the primary
device.
If the failing device is suffering transient problems, new code
retries reset which is a better behavior. If the failing device is
actually broken, the net effect is identical to it, but not to the
other device sharing the channel. In the previous code, reset would
have succeeded after 30s thus detecting the working one. In the new
code, reset fails and whole port gets disabled. IMO, it's a
pathological case anyway (broken device sharing bus with working
one) and doesn't really matter.
* ata_bus_softreset() is changed to return error code from
ata_bus_post_reset(). It used to return 0 unconditionally.
* Spin up waiting is to be removed and not converted to honor
deadline.
* To be on the safe side, deadline is set to 40s for the time being.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
We end up shifting a few bits of logic around in this driver but the
basic change is the same.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Add missing #ifdef CONFIG_PM conditionals around all PM related parts
in libata LLDs.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
This patch is against each libata driver.
Two IRQ calls are added in ata_port_operations.
- irq_on() is used to enable interrupts.
- irq_ack() is used to acknowledge a device interrupt.
In most drivers, ata_irq_on() and ata_irq_ack() are used for
irq_on and irq_ack respectively.
In some drivers (ex: ahci, sata_sil24) which cannot use them
as is, ata_dummy_irq_on() and ata_dummy_irq_ack() are used.
Signed-off-by: Kou Ishizaki <kou.ishizaki@toshiba.co.jp>
Signed-off-by: Akira Iguchi <akira2.iguchi@toshiba.co.jp>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Convert libata core layer and LLDs to use iomap.
* managed iomap is used. Pointer to pcim_iomap_table() is cached at
host->iomap and used through out LLDs. This basically replaces
host->mmio_base.
* if possible, pcim_iomap_regions() is used
Most iomap operation conversions are taken from Jeff Garzik
<jgarzik@pobox.com>'s iomap branch.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Update libata LLDs to use devres. Core layer is already converted to
support managed LLDs. This patch simplifies initialization and fixes
many resource related bugs in init failure and detach path. For
example, all converted drivers now handle ata_device_add() failure
gracefully without excessive resource rollback code.
As most resources are released automatically on driver detach, many
drivers don't need or can do with much simpler ->{port|host}_stop().
In general, stop callbacks are need iff port or host needs to be given
commands to shut it down. Note that freezing is enough in many cases
and ports are automatically frozen before being detached.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
The 8237S was added to the chipsets but not to the comments. Fix this
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
This patch:
* Corrects the wrong device ID of PCI_DEVICE_ID_VIA_SATA_EIDE
from 0x0581 to 0x5324.
* Adds VIA CX700 and VT8237S support in drivers/ide/pci/via82cxxx.c
* Adds VIA VT8237S support in drivers/ata/pata_via.c
Signed-off-by: Josepch Chan <josephchan@via.com.tw>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Make this array static so it doesn't have to be built at runtime.
Cc: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
The UDMA66 VIA hardware has no controller side cable detect bits we can
use. This patch minimally fixes the problem by reporting unknown in this
case and using drive side detection.
The old drivers/ide code does some additional tricks but those aren't
appropriate now we are in -rc.
Without this update UDMA66 via controllers run slowly. They don't fail so
it's a borderline call whether this is -rc material or not.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
This patch implements ATA_FLAG_SETXFER_POLLING and use in pata_via.
If this flag is set, transfer mode setting performed by polling not by
interrupt. This should help those controllers which raise interrupt
before the command is actually complete on SETXFER.
Rationale for this approach.
* uses existing facility and relatively simple
* no busy sleep in the interrupt handler
* updating drivers is easy
While at it, kill now unused flag ATA_FLAG_SRST in pata_via.
Signed-off-by: Tejun Heo <htejun@gmail.com>