Re: [PATCH] ata: ata_generic: use IS_ENABLED() macro

[Sergey Shtylyov <s.shtylyov@omp.ru>]

[Resending after adding the missed test, please ignore the previus reply.)

On 9/10/24 4:09 PM, Damien Le Moal wrote:
[...]

>>>> Replace now gone out of fashion defined(CONFIG_PATA_TOSHIBA[_MODULE])

   I'll probably rephrase this a bit in v2...

>>>> with the new-fangled IS_ENABLED() macro in the ata_generic[] definition.
>>>
>>> Please mention that CONFIG_PATA_TOSHIBA_MODULE actually does not exist at all
>>> and so can be removed.
>>
>>    Huh? =)
>>    CONFIG_PATA_TOSHIBA is a tristate option, so CONFIG_PATA_TOSHIBA_MODULE
>> does exist; else there would be no point in using IS_ENABLED() at all...
> 
> Oops... Indeed. Got confused with something else :)

   There's something to be confused about this driver vs its Kconfig option
naming: the driver is called pata_piccolo.c and its option CONFIG_PATA_TOSHIBA.
However, Toshiba seemingly has more than one family of the PATA controllers:
there's also TC86C001 PCI multi-function chip (dubbed GOKU-S by Toshiba) which
supports up to UDMA66 and doesn't seem compatible with Piccolo, judging by the
driver code and Toshiba GOKU-S datasheet I have: the timing regs are mapped @
AR5 and not in the PCI config space, like with the Piccolo chips.
   If somebody like me (it was me who submitted the reworked Toshiba's TC86C001
driver for drivers/ide/ back in 2007) added TC86C001 libata driver, the confusion
would probably worsen... :-/ Luckily, the chip is a bit tricky (I had to somewhat
abuse drivers/ide/ to work around some "limitations", as Toshiba calls their errata)
and I don't have access to the chip to properly test the driver anymore.  Obviously, there should be a little interest now in adding the "new" PATA drivers... :-)
   Any thoughts on the naming confusion?

>>>> Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
>>
>> [...[
>>
>>>> Index: linux/drivers/ata/ata_generic.c
>>>> ===================================================================
>>>> --- linux.orig/drivers/ata/ata_generic.c
>>>> +++ linux/drivers/ata/ata_generic.c
>>>> @@ -220,7 +220,7 @@ static struct pci_device_id ata_generic[
>>>>  	{ PCI_DEVICE(PCI_VENDOR_ID_OPTI,   PCI_DEVICE_ID_OPTI_82C558), },
>>>>  	{ PCI_DEVICE(PCI_VENDOR_ID_CENATEK,PCI_DEVICE_ID_CENATEK_IDE),
>>>>  	  .driver_data = ATA_GEN_FORCE_DMA },
>>>> -#if !defined(CONFIG_PATA_TOSHIBA) && !defined(CONFIG_PATA_TOSHIBA_MODULE)
>>>> +#if !IS_ENABLED(CONFIG_PATA_TOSHIBA)
>>>
>>> I do not understand the negation here... It seems very wrong. If the driver is
>>> indeed enabled, we need to add its PCI ID, no ? and the reverse when not defined...
>>
>>    The separate driver was added by Alan Cox in 2009, before that
>> Toshiba Piccolo controllers were handled by this generic driver...
> 
> OK, makes sense now. Maybe we should add a comment above that IS_ENABLED() to
> say so ?

   Makes sense, indeed. Do you think this is acceptable to be done in v2 of this
patch?

MBR, Sergey