Re: [PATCH v11 0/6] PCI EP driver support MSI doorbell from host

Marc Zyngier
2022-09-28T13:35:08Z

On Thu, 22 Sep 2022 12:12:40 -0400,
Frank Li <Frank.Li@nxp.com> wrote:
>
>
>
> ┌───────┐ ┌──────────┐
> │ │ │ │
> ┌─────────────┐ │ │ │ PCI Host │
> │ MSI │◄┐ │ │ │ │
> │ Controller │ │ │ │ │ │
> └─────────────┘ └─┼───────┼──────────┼─Bar0 │
> │ PCI │ │ Bar1 │
> │ Func │ │ Bar2 │
> │ │ │ Bar3 │
> │ │ │ Bar4 │
> │ ├─────────►│ │
> └───────┘ └──────────┘
>
> Many PCI controllers provided Endpoint functions.
> Generally PCI endpoint is hardware, which is not running a rich OS,
> like linux.
>
> But Linux also supports endpoint functions. PCI Host write BAR<n> space
> like write to memory. The EP side can't know memory changed by the Host
> driver.
>
> PCI Spec has not defined a standard method to do that. Only define
> MSI(x) to let EP notified RC status change.

[...]

FWIW, I have queued the first 4 patches of this series into -next. If
there is a need for these patches to be pulled by another subsystem, I
have pushed out a stable branch at [1].

Thanks,

M.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git/log/?h=irq/fsl-mu-msi

--
Without deviation from the norm, progress is not possible.