On Wed, Jan 08, 2025 at 07:38:30PM +0100, Marek Vasut wrote:
On 1/8/25 3:55 AM, Alice Guo (OSS) wrote:
-----邮件原件----- 发件人: Marek Vasut marex@denx.de 发送时间: 2025年1月7日 19:11 收件人: Alice Guo (OSS) alice.guo@oss.nxp.com; Tom Rini trini@konsulko.com; Stefano Babic sbabic@denx.de; Fabio Estevam festevam@gmail.com; dl-uboot-imx uboot-imx@nxp.com; Lukasz Majewski lukma@denx.de; Sean Anderson seanga2@gmail.com; Simon Glass sjg@chromium.org; Alper Nebi Yasak alpernebiyasak@gmail.com 抄送: u-boot@lists.denx.de; tharvey@gateworks.com; Viorel Suman viorel.suman@nxp.com; Ye Li ye.li@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@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 ?
Here to i.MX SM, this is just a doorbell to tell remote side that info is ready. To U-Boot i.MX, MU GSR set means SM sends data back, so with COMP_INT set, U-Boot could poll the MU GSR bit. Using interrupt here is not that accurate, it is just a doorbell.
For OP-TEE, it is using SMC, it is sync transports, SMC return means SCMI done. No need polling any bit or else.
Regards, Peng