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>
->irq_clear() is used to clear IRQ bit of a SFF controller and isn't
useful for drivers which don't use libata SFF HSM implementation.
However, it's a required callback and many drivers implement their own
noop version as placeholder. This patch implements ata_noop_irq_clear
and use it to replace those custom placeholders.
Also, SFF drivers which don't support BMDMA don't need to use
ata_bmdma_irq_clear(). It becomes noop if BMDMA address isn't
initialized. Convert them to use ata_noop_irq_clear().
Signed-off-by: Tejun Heo <htejun@gmail.com>
that provided by the block layer
ATA requires that all DMA transfers begin and end on word boundaries.
Because of this, a large amount of machinery grew up in ide to adjust
scatterlists on this basis. However, as of 2.5, the block layer has a
dma_alignment variable which ensures both the beginning and length of a
DMA transfer are aligned on the dma_alignment boundary. Although the
block layer does adjust the beginning of the transfer to ensure this
happens, it doesn't actually adjust the length, it merely makes sure
that space is allocated for transfers beyond the declared length. The
upshot of this is that scatterlists may be padded to any size between
the actual length and the length adjusted to the dma_alignment safely
knowing that memory is allocated in this region.
Right at the moment, SCSI takes the default dma_aligment which is on a
512 byte boundary. Note that this aligment only applies to transfers
coming in from user space. However, since all kernel allocations are
automatically aligned on a minimum of 32 byte boundaries, it is safe to
adjust them in this manner as well.
tj: * Adjusting sg after padding is done in block layer. Make libata
set queue alignment correctly for ATAPI devices and drop broken
sg mangling from ata_sg_setup().
* Use request->raw_data_len for ATAPI transfer chunk size.
* Killed qc->raw_nbytes.
* Separated out killing qc->n_iter.
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
libata used private sg iterator to handle padding sg. Now that sg can
be chained, padding can be handled using standard sg ops. Convert to
chained sg.
* s/qc->__sg/qc->sg/
* s/qc->pad_sgent/qc->extra_sg[]/. Because chaining consumes one sg
entry. There need to be two extra sg entries. The renaming is also
for future addition of other extra sg entries.
* Padding setup is moved into ata_sg_setup_extra() which is organized
in a way that future addition of other extra sg entries is easy.
* qc->orig_n_elem is unused and removed.
* qc->n_elem now contains the number of sg entries that LLDs should
map. qc->mapped_n_elem is added to carry the original number of
mapped sgs for unmapping.
* The last sg of the original sg list is used to chain to extra sg
list. The original last sg is pointed to by qc->last_sg and the
content is stored in qc->saved_last_sg. It's restored during
ata_sg_clean().
* All sg walking code has been updated. Unnecessary assertions and
checks for conditions the core layer already guarantees are removed.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Currently, port configuration reporting has the following problems.
* iomapped address is reported instead of raw address
* report contains irrelevant fields or lacks necessary fields for
non-SFF controllers.
* host->irq/irq2 are there just for reporting and hacky.
This patch implements and uses ata_port_desc() and
ata_port_pbar_desc(). ata_port_desc() is almost identical to
ata_ehi_push_desc() except that it takes @ap instead of @ehi, has no
locking requirement, can only be used during host initialization and "
" is used as separator instead of ", ". ata_port_pbar_desc() is a
helper to ease reporting of a PCI BAR or an offsetted address into it.
LLD pushes whatever description it wants using the above two
functions. The accumulated description is printed on host
registration after "[S/P]ATA max MAX_XFERMODE ".
SFF init helpers and ata_host_activate() automatically add
descriptions for addresses and irq respectively, so only LLDs which
isn't standard SFF need to add custom descriptions. In many cases,
such controllers need to report different things anyway.
Signed-off-by: Tejun Heo <htejun@gmail.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>
* ->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>
Alan Cox suggested that the solution to the FIXMEs in pata_icside is
to use a private postreset method to detect the lack of devices on a
port, and in such a case, disable the interrupt for the port.
This patch implements such a method, and removes the hard coded
disable of port 0. Tested as working.
Acked-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This flag only has meaning in old-EH drivers, and these drivers have
already been converted to the new EH. Remove.
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Building on the previous two ecard infrastructure changes, this patch
fixes the pata_icside build errors caused by the recent libata changes.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Add devres ecardm_iomap() and ecardm_iounmap() for Acorn expansion
cards. Convert all expansion card drivers to use them.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Rather than having every driver fiddle about setting its private
IRQ operations and data, provide a helper function to contain
this functionality in one place.
Arrange to remove the driver-private IRQ operations and data when
the device is removed from the driver, and remove the driver
private code to do this.
This fixes potential problems caused by drivers forgetting to
remove these hooks.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
