diff mbox series

[v3,4/5] ARM: footbridge: limit CONFIG_ISA to CATS

Message ID 20220909205749.1793677-5-arnd@kernel.org (mailing list archive)
State New, archived
Headers show
Series ARM: footbridge: cleanups | expand

Commit Message

Arnd Bergmann Sept. 9, 2022, 8:57 p.m. UTC 
From: Arnd Bergmann <arnd@arndb.de>

The CONFIG_ISA option is only used for actual add-in cards, not
on-board devices. NetWinder has no hardware support for those,
and ebsa285 appears to not support them in Linux, as the XBUS
is not set up that way and there is no support for a PCI-ISA
bridge.

CATS on the other hand has four ISA slots connected to a PCI-ISA
bridge device.

Russell mentioned that it is no longer possible to select the sound
drivers for Netwinder after this, as the WaveArtist sound chip is
connected to the ISA bus. However, the WaveArtist module was removed
years ago in linux-4.15 and did not actually depend on CONFIG_ISA.
While the SoundBlaster compatibility mode of the SoundChip might work
with the ALSA sb16-isa driver with a little help, there is no mixer
support without the waveartist driver, and the default settings for
sb16 never probe IRQ 3.

Link: https://lore.kernel.org/linux-arm-kernel/87v8q3unlv.wl-maz@kernel.org/
Tested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 arch/arm/mach-footbridge/Kconfig | 2 --
 1 file changed, 2 deletions(-)

Comments

Russell King (Oracle) Sept. 11, 2022, 7:53 p.m. UTC | #1 
On Fri, Sep 09, 2022 at 10:57:48PM +0200, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> The CONFIG_ISA option is only used for actual add-in cards, not
> on-board devices. NetWinder has no hardware support for those,
> and ebsa285 appears to not support them in Linux, as the XBUS
> is not set up that way and there is no support for a PCI-ISA
> bridge.

That is an incorrect assumption, but is still true as far as ISA
DMA is concerned.

The "Team" produced a PCI card with a PCI southbridge chip on, along
with ISAPNP devices. ISAPNP depends on CONFIG_ISA... That said, using
the "ESS ES1879 Plug and Play AudioDrive" on it requires ISA DMA, and
as DMA from the PCI southbridge causes the PCI bus to deadlock, it
probably doesn't matter.

However, what I'm pointing out is that the assertion that CONFIG_ISA
means ISA cards is not entirely correct with the creation of this
PCI southbridge card.

(This card gives me keyboard, mouse, serial etc ports which is its
main use in the machine.)
Arnd Bergmann Sept. 15, 2022, 2 p.m. UTC | #2 
On Sun, Sep 11, 2022, at 9:53 PM, Russell King (Oracle) wrote:
> On Fri, Sep 09, 2022 at 10:57:48PM +0200, Arnd Bergmann wrote:
>> From: Arnd Bergmann <arnd@arndb.de>
>> 
>> The CONFIG_ISA option is only used for actual add-in cards, not
>> on-board devices. NetWinder has no hardware support for those,
>> and ebsa285 appears to not support them in Linux, as the XBUS
>> is not set up that way and there is no support for a PCI-ISA
>> bridge.
>
> That is an incorrect assumption, but is still true as far as ISA
> DMA is concerned.
>
> The "Team" produced a PCI card with a PCI southbridge chip on, along
> with ISAPNP devices. ISAPNP depends on CONFIG_ISA... That said, using
> the "ESS ES1879 Plug and Play AudioDrive" on it requires ISA DMA, and
> as DMA from the PCI southbridge causes the PCI bus to deadlock, it
> probably doesn't matter.
>
> However, what I'm pointing out is that the assertion that CONFIG_ISA
> means ISA cards is not entirely correct with the creation of this
> PCI southbridge card.
>
> (This card gives me keyboard, mouse, serial etc ports which is its
> main use in the machine.)

I dropped the patch now, and queued the rest of the series for
the 6.1 merge window.

      Arnd
diff mbox series

Patch

diff --git a/arch/arm/mach-footbridge/Kconfig b/arch/arm/mach-footbridge/Kconfig
index 1a3676109654..cd18871fd03f 100644
--- a/arch/arm/mach-footbridge/Kconfig
+++ b/arch/arm/mach-footbridge/Kconfig
@@ -18,7 +18,6 @@  config ARCH_CATS
 config ARCH_EBSA285_HOST
 	bool "EBSA285 (host mode)"
 	select ARCH_EBSA285
-	select ISA
 	select ARCH_MAY_HAVE_PC_FDC
 	select FORCE_PCI
 	help
@@ -31,7 +30,6 @@  config ARCH_NETWINDER
 	bool "NetWinder"
 	select CLKEVT_I8253
 	select CLKSRC_I8253
-	select ISA
 	select FORCE_PCI
 	help
 	  Say Y here if you intend to run this kernel on the Rebel.COM