Hello.
Graeme Russ wrote:
[Added linux-ide back onto distribution list]
Right, I didn't intend to exclude it -- probably didn't press all the
keys at once for the reply-to-all function.
[...]
You should have also taught the symmetric ide-platfrom driver the same
trick. However, IDE core's data transfer methods has a different prototype.
I did think about the other drivers (OF Platform etc) but I have no way of
testing them.
pata_of_platform is not easily extensible in this way. It gets all
the information about the device from the device tree -- and you can't
encode all your complications there, unless you invent a new OF device.
I suggest to rather add a new flag, indicating 8-bit data I/O, and have
the alternate sff_data_xfer() method defined inside the driver.
Well actually it goes beyond simply implementing 8-bit data transfers - On
my particular board, the PATA devices (2x CF slots) are on a General
Purpose Bus with a few other peripherals. The timing requirements for the
bus when accessing the CF cards are very strict (and very slow compared to
other devices on the bus). By overriding the data transfer function I can
arbitrate access to the bus and switch the bus timings based on the
peripheral being accessed. This cannot be done be a generic data transfer
function.
I disagree with your approach of overriding the libata methods at the
board level, so I suggest to write a new driver. This is too complicated
stuff for poor old pata_platform. :-)
Regards,
Graeme
MBR, Sergei
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