From: "Neil Armstrong" <neil.armstrong@linaro.org>
To: Simon Glass <sjg@google.com>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>,
Alexey Romanov <AVRomanov@sberdevices.ru>,
"narmstrong@baylibre.com" <narmstrong@baylibre.com>,
"u-boot-amlogic@groups.io" <u-boot-amlogic@groups.io>,
"u-boot@lists.denx.de" <u-boot@lists.denx.de>,
kernel <kernel@sberdevices.ru>
Subject: Re: [PATCH v1 1/2] drivers: firmware: introduce Meson Secure Monitor driver
Date: Tue, 22 Aug 2023 10:24:23 +0200 [thread overview]
Message-ID: <7a9f5cf0-d7b2-4477-8a56-a3aa7f764e2a@linaro.org> (raw)
In-Reply-To: <CAPnjgZ2GA7ktNi9HVJ1Mw=4nuqcQJALVBqHQr1_JtVmkzEVgdw@mail.gmail.com>
On 21/08/2023 21:11, Simon Glass wrote:
> Hi Neil,
>
> On Mon, 21 Aug 2023 at 03:16, neil.armstrong@linaro.org
> <neil.armstrong@linaro.org> wrote:
>>
>> Hi,
>>
>> On 16/07/2023 01:40, Simon Glass wrote:
>>> Hi,
>>>
>>> On Thu, 13 Jul 2023 at 23:30, AKASHI Takahiro
>>> <takahiro.akashi@linaro.org> wrote:
>>>>
>>>> On Tue, Jul 11, 2023 at 01:13:29PM -0600, Simon Glass wrote:
>>>>> +AKASHI Takahiro
>>>>
>>>> Me?
>>>
>>> Yes, I'm asking for your help to try to clean this stuff up.
>>
>> The thread is long and hard to answer directly, but as AKASHI
>> said there's no point to add a SMC class since it's only the message
>> passing instruction, and there's no point using remoteproc since the
>> firmware runs on a separate secure state of the same CPU.
>>
>> And I don't see how we can actually define a finite set of ops because
>> none of the secure firmware interfaces has even similar functions.
>>
>> So a new UCLASS for each firmware interface should be added, not sure
>> this is scalable or required since those firmwares are mainly SoC or
>> vendor specific, except the PSCI or other ARM specific interfaces of course.
>>
>> So I think UCLASS_FIRMWARE is good enough since it avoids using UCLASS_MISC,
>> but it should be probably documented somewhere that the ops are implementation
>> defined.
>
> Yes it needs docs...but what exactly is the 'firmware' uclass? I
> assumed it was for loading firmware into a device, but it seems that
> it is something else?
Nop, it's based on the same "firmware" naming as Linux, which is an interface
with a system control firmware like PSCI, SCPI... not to interact with loadable
co-processors.
Systems do have multiple interfaces implemented like PSCI, SCPI, OPTEE and other
vendor specific ones like Alexey is changing, all via the same instruction call.
>
> Perhaps we should have a UCLASS_SVC (supervisor call) or something
> like that, rather than continuing with firmware?
I have no opinion on that, I don't think the call type is significant here.
Neil
>
> [..]
>
> Regards,
> Simon
prev parent reply other threads:[~2023-08-22 8:24 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20230706112020.24528-1-avromanov@sberdevices.ru>
[not found] ` <20230706112020.24528-2-avromanov@sberdevices.ru>
[not found] ` <CAPnjgZ1AqUYxAU0BNhxZLXc+y_h5XKbuoLBDekbkqzaJeon-1Q@mail.gmail.com>
[not found] ` <20230707084313.vecmsr5z3aj4gqxs@cab-wsm-0029881>
[not found] ` <CAPnjgZ3Wfnc_rMJBVZTv_eikUu7vpPWsL1MQ_SruXySV9EZi3A@mail.gmail.com>
[not found] ` <20230710083443.fuw74gbvwoha75ab@cab-wsm-0029881>
[not found] ` <CAPnjgZ1aZsFBaX2eBh35CXVExaE90YJHQ98S+2XOWJrJ9pz37w@mail.gmail.com>
[not found] ` <20230711102459.phpyem2ehlya7osz@cab-wsm-0029881.sigma.sbrf.ru>
[not found] ` <CAPnjgZ2t2xf05PSgCbQr7MUvJrpQPcRs_Zoux804h4UmTrZRKw@mail.gmail.com>
[not found] ` <ZLDdaIyXjp9yN5aW@laputa>
[not found] ` <CAPnjgZ3oQ1qZtWFpezNfV-dZhbCrnqbi1+B=JKb1sfJP6xk-cA@mail.gmail.com>
2023-08-21 9:16 ` [PATCH v1 1/2] drivers: firmware: introduce Meson Secure Monitor driver Neil Armstrong
[not found] ` <CAPnjgZ2GA7ktNi9HVJ1Mw=4nuqcQJALVBqHQr1_JtVmkzEVgdw@mail.gmail.com>
2023-08-22 8:24 ` Neil Armstrong [this message]
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