Bartlomiej Zolnierkiewicz escreveu:
On Friday 08 May 2009 19:28:22 João Ramos wrote:
Yes! :)
There is still a room for improvement though -- it would be better to fix
IDE core to set PIO0 before probing devices for all host controllers.
Moreover it seems that doing it this way would allow us to remove ->init_hwif
method from this driver and do all necessary setup in ep93xx_ide_probe()
(this controller is a single port one so theoretically there shouldn't be
a need for having per-port ->init_hwif implementation).
So after all this discussion ;-) , my driver will have no 'init_hwif'
method, and the setup code will be on 'ep93xx_ide_probe', which will
configure entirely the IDE host controller.
Moreover, this initial configuration will setup the controller to work
at PIO Mode 0. Later on, the 'set_pio_mode' method will be called and
the controller will configure itself according to the PIO mode reported
by the IDE core.
Can I proceed this way?
Well, yes. Though I hoped that you would at least give a try to fixing
IDE core to program PIO0 initially for all host drivers that implement
->set_pio_mode method...
Sorry, I didn't noticed your hint... Sure, I can give it a try ;-)
Maybe with a little help, but I can try. You mean, when the host driver
is registered (ide_host_register, or ide_host_add that later calls
ide_host_register), maybe in the 'ide_init_port' method (sorry, I need
some guidance here...) check if the 'set_pio_mode' method is
implemented, and after initializing each port (d->init_hwif(hwif))
default it to PIO Mode 0, calling set_pio_mode method.
Is this correct? Sorry, has I stated earlier, I'm wasn't familiar with
the IDE susbsystem untill I wrote this patch; but I'm willing to
contribute in any way I can, so please, bear with me on this :-) .
There's just only one issue; normally, I would setup the specific
timings (t0, t1, t2, t2i, etc) in the 'pio_set_mode' hook. However, if
you look further in the driver, those timings aren't defined through a
memory controller but instead manually enforced by 'ndelay' calls (arghhh).
This means that in my low-level procedures for reading and writing, I
need to have access to the timings (or the struct ide_timing)
corresponding to the PIO mode selected, in order to use the correct delays.
My question is: which is the best way to accomplish this? Declaring a
global struct ide_timing variable pointer that always holds the correct
ide_timing struct to the selected PIO mode? Or should I always check (in
some manner) what is the current PIO mode and then select the adequate
delays?
I think that the setting variable pointer in ->set_pio_mode method would
work best. Seems like the existing drive_data field of ide_drive_t is well
suited for this purpose (however it may be worth to convert it to 'void *'
type while we are it).
Did you mean 'drive_data' field, or 'driver_data' field?
'drive_data' field is an unsigned int value; I guess you meant
'driver_data' field as it is a (void *) field, so I can define it as a
pointer to the correct 'struct ide_timing'.
That is why I hinted that you may need to convert 'drive_data' to
'void *' type first. You may also try to use 'driver_data' instead
but you will discover rather quickly that you shouldn't do this... ;)
'driver_data' is for use by IDE core and IDE device drivers.
'drive_data' is for use by IDE host drivers.
And this conversion is made by my driver code, or should I fix directly
in the ide_drive_t structure?
Regards,
João Ramos
Thanks,
Bart
--
************************************************************************
João Ramos <joao.ramos@xxxxxxx>
INOV INESC Inovação - ESTG Leiria
Escola Superior de Tecnologia e Gestão de Leiria
Edíficio C1, Campus 2
Morro do Lena, Alto do Vieiro
Leiria
2411-901 Leiria
Portugal
Tel: +351244843424
Fax: +351244843424
************************************************************************
--
To unsubscribe from this list: send the line "unsubscribe linux-ide" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
