On Friday 08 May 2009 20:16:56 João Ramos wrote: > 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. ide_init_port() seems OK but I think that ide_port_init_devices() [it is called after ide_init_port()] would be a bit safer and more flexible (some host drivers may also require special ->init_dev setup first) and the check for ->set_pio_mode method presence can be done just before actually using the method, i.e. const struct ide_port_ops *port_ops = hwif->port_ops; if (port_ops && port_ops->set_pio_mode) port_ops->set_pio_mode(...) > 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 :-) . Sure, nobody starts from the expert level and not all maintainers are into "prove the maintainer wrong" elitist's idiocy. ;) > > > >>> > >>> > >>>> 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? The latter -- ide_drive_t is the place needing fixing. Thanks, Bart -- 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
