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From: "Cédric Le Goater" <clg@kaod.org>
To: Troy Lee <leetroy@gmail.com>
Cc: Peter Maydell <peter.maydell@linaro.org>,
	Andrew Jeffery <andrew@aj.id.au>,
	Troy Lee <troy_lee@aspeedtech.com>,
	qemu-devel@nongnu.org, hailin.wu@aspeedtech.com,
	"open list:ASPEED BMCs" <qemu-arm@nongnu.org>,
	Joel Stanley <joel@jms.id.au>
Subject: Re: [PATCH v2 1/2] hw/misc: Implementating dummy AST2600 I3C model
Date: Tue, 11 Jan 2022 09:25:38 +0100	[thread overview]
Message-ID: <cbeab84b-2d50-3713-63d9-6d8f2af5c85f@kaod.org> (raw)
In-Reply-To: <CAN9Jwz0qFQKe5HuTMwo-u=1vSh47gXJm9DU2wdOjgH8ZcbAsAw@mail.gmail.com>

Hello Troy,


>>> +
>>> +    memory_region_init_io(&s->iomem, OBJECT(s), &aspeed_i3c_ops, s,
>>> +            TYPE_ASPEED_I3C, ASPEED_I3C_NR_REGS << 2);
>>> +
>>> +    sysbus_init_mmio(sbd, &s->iomem);
>>
>> I would add a container region containing all the regions :
>>
>>
>>       memory_region_init(&s->iomem_container, OBJECT(s),
>>                          TYPE_ASPEED_I3C ".container", 0x8000);
>>
>>       sysbus_init_mmio(sbd, &s->iomem_container);
>>
>>       memory_region_init_io(&s->iomem, OBJECT(s), &aspeed_i3c_ops, s,
>>               TYPE_ASPEED_I3C ".regs", 0x70);
>>
>>       memory_region_add_subregion(&s->iomem_container, 0x0, &s->iomem);
>>
>>
>>
>> The goal is to have a stricter layout so that you can catch errors :
>>
>>       000000001e7a0000-000000001e7a7fff (prio 0, i/o): aspeed.i3c.container
>>         000000001e7a0000-000000001e7a006f (prio 0, i/o): aspeed.i3c.regs
>>         000000001e7a2000-000000001e7a22ff (prio 0, i/o): aspeed.i3c.device.0
>>         000000001e7a3000-000000001e7a32ff (prio 0, i/o): aspeed.i3c.device.1
>>         000000001e7a4000-000000001e7a42ff (prio 0, i/o): aspeed.i3c.device.2
>>         000000001e7a5000-000000001e7a52ff (prio 0, i/o): aspeed.i3c.device.3
>>         000000001e7a6000-000000001e7a62ff (prio 0, i/o): aspeed.i3c.device.4
>>         000000001e7a7000-000000001e7a72ff (prio 0, i/o): aspeed.i3c.device.5
>>
>> and if under U-Boot, you peek into unimplemented regs, you get a warning :
>>
>>       ast# md 1e7a0000
>>       1e7a0000: 00000000 00000000 00000000 00000000    ................
>>       1e7a0010: 00000000 00000000 00000000 00000000    ................
>>       1e7a0020: 00000000 00000000 00000000 00000000    ................
>>       1e7a0030: 00000000 00000000 00000000 00000000    ................
>>       1e7a0040: 00000000 00000000 00000000 00000000    ................
>>       1e7a0050: 00000000 00000000 00000000 00000000    ................
>>       1e7a0060: 00000000 00000000 00000000 00000000    ................
>>       1e7a0070:aspeed_soc.io: unimplemented device read  (size 4, offset 0x1a0070)
>>        00000000aspeed_soc.io: unimplemented device read  (size 4, offset 0x1a0074)
> 
> Thanks for the code snippet, learnt and applied.
> Yes, it would be easier to catch driver problems.

That said, not all Aspeed models follow this pattern. We learned along
the way and we could improve some older implementations.

btw, I tried your series with ast2600-default-obmc.tar.gz. It boots fine.

Thanks,

C.


  reply	other threads:[~2022-01-11  8:28 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-10  7:21 [PATCH v2 0/2] Aspeed I3C device model Troy Lee
2022-01-10  7:21 ` [PATCH v2 1/2] hw/misc: Implementating dummy AST2600 I3C model Troy Lee
2022-01-10 14:25   ` Cédric Le Goater
2022-01-11  7:48     ` Troy Lee
2022-01-11  8:25       ` Cédric Le Goater [this message]
2022-01-10  7:21 ` [PATCH v2 2/2] hw/arm/aspeed_ast2600: create i3c instance Troy Lee
2022-01-10 14:31   ` Cédric Le Goater
2022-01-11  7:55     ` Troy Lee

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