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); } }
Best Regards, Alice Guo