Re: [PATCH] m68k/mac: Replace macide driver with generic platform driver

From: Finn Thain
Date: Mon Apr 26 2021 - 03:47:01 EST

On Sun, 25 Apr 2021, John Paul Adrian Glaubitz wrote:

> On 4/25/21 11:06 AM, Finn Thain wrote:
> > This was tested on my Quadra 630. I haven't tested it on my PowerBook 150
> > because I don't have a RAM adapter board for it.
> >
> > Apparently, the hardware I tested doesn't need macide_clear_irq() or
> > macide_test_irq() -- if it did, the generic driver would not have worked.
> > It's possible that those routines are needed for the PowerBook 150 but
> > we can cross that bridge if and when we come to it.
> >
> > BTW, macide_clear_irq() appears to suffer from a race condition. The write
> > to the interrupt flags register could easily have unintended side effects
> > as it may alter other flag bits. Fortunately, all of the other bits are
> > unused by Linux. Moreover, when tested on my Quadra 630, that assignment
> > (*ide_ifr &= ~0x20) was observed to have no effect on bit 5.
> Shouldn't we switch to a libata driver instead with legacy IDE been slated
> for removal from the Linux kernel?

This patch means that the Quadra 630/580 config will work the same as the
Powerbook 190 config. Please see commit 50c5feeea0af ("ide/macide: Convert
Mac IDE driver to platform driver") for some background.

This patch also means that the kernel/drivers/ide/macide.ko driver module
will disappear completely. The module that will replace it is up to you.

If you enable CONFIG_IDE and CONFIG_BLK_DEV_PLATFORM, Quadras and
Powerbooks will use the kernel/drivers/ide/ide_platform.ko module.

If you enable CONFIG_ATA and CONFIG_PATA_PLATFORM, Quadras and
Powerbooks will use the kernel/drivers/ata/pata_platform.ko module.

(If you enable all of the above, you may need to use a blacklist to ensure
that the preferred driver module gets loaded.)

Was macide the only IDE driver in Debian/m68k kernels without a libata
alternative? If so, this patch would allow you to finally drop CONFIG_IDE.

> Adrian
> --
> .''`. John Paul Adrian Glaubitz
> : :' : Debian Developer - glaubitz@xxxxxxxxxx
> `. `' Freie Universitaet Berlin - glaubitz@xxxxxxxxxxxxxxxxxxx
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