Re: 回复: 回复: 回复: [EXT] Re: [PATCH v3 02/17] firmware: scmi: smt: Interrupt communication enable

[Marek Vasut]

On 1/8/25 3:55 AM, Alice Guo (OSS) wrote:
>> -----邮件原件-----
>> 发件人: Marek Vasut <marex at denx.de>
>> 发送时间: 2025年1月7日 19:11
>> 收件人: Alice Guo (OSS) <alice.guo at oss.nxp.com>; Tom Rini
>> <trini at konsulko.com>; Stefano Babic <sbabic at denx.de>; Fabio Estevam
>> <festevam at gmail.com>; dl-uboot-imx <uboot-imx at nxp.com>; Lukasz
>> Majewski <lukma at denx.de>; Sean Anderson <seanga2 at gmail.com>; Simon
>> Glass <sjg at chromium.org>; Alper Nebi Yasak <alpernebiyasak at gmail.com>
>> 抄送: u-boot at lists.denx.de; tharvey at gateworks.com; Viorel Suman
>> <viorel.suman at nxp.com>; Ye Li <ye.li at nxp.com>
>> 主题: Re: 回复: 回复: [EXT] Re: [PATCH v3 02/17] firmware: scmi: smt:
>> Interrupt communication enable
>>
>> On 1/7/25 4:24 AM, Alice Guo (OSS) wrote:
>>>> 主题: Re: 回复: [EXT] Re: [PATCH v3 02/17] firmware: scmi: smt: Interrupt
>>>> communication enable
>>>>
>>>> On 1/6/25 7:17 AM, Alice Guo (OSS) wrote:
>>>>>> On 1/3/25 7:45 AM, Alice Guo wrote:
>>>>>>> From: Viorel Suman <viorel.suman at nxp.com>
>>>>>>>
>>>>>>> When interrupt driven communication is supported
>>>>>>
>>>>>> U-Boot does not use interrupts.
>>>>>>
>>>>>>> , the transport allows
>>>>>>> the caller to choose between interrupt and polling driven
>>>>>>> communications. To make the choice, the channel flags are used.
>>>>>>> i.MX95 uses interrupt driven communication so that Channel flags
>>>>>>> should be set to 1.
>>>>>>
>>>>>> How does this work in U-Boot, which does not use interrupts ?
>>>>>
>>>>> Hi Marek,
>>>>>
>>>>> The clearer explanation will be added in the commit log.
>>>>>
>>>>> This is based on Arm® System Control and Management Interface
>>>>> Platform
>>>> Design Document Version 3.2 (Document number: DEN0056E) 5.1.2. When
>>>> Bit[0] of Channel flags is 1, the System Manager runs on M core will
>>>> trigger general-purpose interrupts to A core. U-Boot polls
>>>> General-purpose Status (GSR) until GIPn is set.
>>>> If U-Boot does polling, why does this bit need to be set, shouldn't
>>>> the bit be cleared instead ?
>>>
>>> My commit log may have caused your misunderstanding. If the bit is not set,
>> the System Manager will not request doorbell interrupt. The following is the
>> code from imx-sm:
>>>
>>>               if (callee)
>>>               {
>>>                   /* Generate completion interrupt */
>>>                   if ((buf->channelFlags & SMT_COMP_INT) != 0U)
>>>                   {
>>>                       status = RPC_SMT_DoorbellRing(smtChannel);
>>>                   }
>>>               }
>> Can the SM be updated instead ?
> 
> System Manager not only interacts with U-Boot, but also with Linux/QNX/RTOS. System Manager cannot be changed.
How come other SCMI providers (like optee) do not need this kind of change ?