Re: [Qemu-devel] [PATCHv2 3/3] Split ISA and sysbus versions of m48t59 device

[Markus Armbruster <armbru@redhat.com>]

Paolo Bonzini <pbonzini@redhat.com> writes:

> ----- Original Message -----
>> From: "Mark Cave-Ayland" <mark.cave-ayland@ilande.co.uk>
>> To: "Paolo Bonzini" <pbonzini@redhat.com>, "David Gibson" <david@gibson.dropbear.id.au>, "edgar iglesias"
>> <edgar.iglesias@gmail.com>, michael@walle.cc, proljc@gmail.com, borntraeger@de.ibm.com, "cornelia huck"
>> <cornelia.huck@de.ibm.com>, kbastian@mail.uni-paderborn.de, jcmvbkbc@gmail.com
>> Cc: veroniabahaa@gmail.com, "peter maydell" <peter.maydell@linaro.org>, mst@redhat.com, armbru@redhat.com,
>> qemu-devel@nongnu.org, agraf@suse.de
>> Sent: Thursday, November 10, 2016 4:16:36 PM
>> Subject: Re: [Qemu-devel] [PATCHv2 3/3] Split ISA and sysbus versions of m48t59 device
>> 
>> On 10/11/16 14:57, Paolo Bonzini wrote:
>> > 
>> > 
>> > On 09/11/2016 13:22, David Gibson wrote:
>> >> The m48t59 device supports both ISA and direct sysbus attached versions of
>> >> the device in the one .c file.  This can be awkward for some embedded
>> >> machine types which need the sysbus M48T59, but don't want to pull in the
>> >> ISA bus code and its other dependencies.
>> >>
>> >> Therefore, this patch splits out the code for the ISA attached M48T59 into
>> >> its own C file.  It will be built when both CONFIG_M48T59 and
>> >> CONFIG_ISA_BUS are enabled.
>> >>
>> >> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
>> > 
>> > Who needs the ISA M48T59?  Perhaps it should be a separate symbol
>> > altogether.  Let's document that SPARC will stop providing it in 2.9,
>> > for example, if it's only a PReP thing.
>> > 
>> > Paolo
>> 
>> Hi Paolo,
>> 
>> The ISA M48T59 is still actively used by the sun4u machine on
>> qemu-system-sparc64. In real terms it's actually connected to the ebus,
>> but for all intents and purposes it's the same as an ISA bus connected
>> via a PCI bridge.
>
> sun4u is actually using the sysbus M48T59, and mapping it into the ebus
> space:
>
>     nvram = m48t59_init(NULL, 0, 0, NVRAM_SIZE, 1968, 59);
>     s = SYS_BUS_DEVICE(nvram);
>     memory_region_add_subregion(get_system_io(), 0x2000,
>                                 sysbus_mmio_get_region(s, 0));

As far as I can tell, only machine "prep" uses ISA M48T59.

Is David's patch okay as is, Paolo?