Alan Cox wrote:
The second FIXME area is ata_irq_ack - it is unconditionally coded
for SFF-type interfaces. I believe that using this function in
non-BMDMA interfaces is wrong - it attempts to read from the BMDMA
registers irrespective of whether ap->ioaddr.bmdma_addr is set or
not. The question this poses is: what should non-BMDMA implementations
use for this method? Note that pata_platform also uses this
function despite not supporting BMDMA which seems even more suspicious.
Thats a bug that has arrived again. The older code was corrected to
handle this properly but the fix appears to have become lost. The
ioread/iowrite code actually made quite a mess (all the address reporting
is also broken) and we do some iffy things like compare the iomap result
with zero and assume thats the same as checking for true bus zero
addresses.
ata_irq_ack is part of the SFF layer so its fine that it assumes SFF but
its wrong that it is used unconditionally and it shouldn't be used this
way. It just needs a (!ap->ioaddr.bmdma_addr) test adding (assuming thats
valid for iomap)
No. It does not need such a test, as it requires BMDMA, not just an
SFF-style Status register. It is up to the driver to decide whether or
not ata_irq_ack() is appropriate for your hardware.
pata_icside needs its own ata_irq_ack -- which may just be as simple as
reading the Status register to clear the interrupt condition.
If others need this as well, ata_sff_irq_ack() would be a good generic
function to create.
Jeff
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