lkml.org 
[lkml]   [2021]   [Jan]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [RFC PATCH 6/7] arm64: kernel: Apple CPU start driver
On Wed, Jan 20, 2021 at 2:27 PM Mohamed Mediouni
<mohamed.mediouni@caramail.com> wrote:
> diff --git a/Documentation/devicetree/bindings/arm/cpus.yaml b/Documentation/devicetree/bindings/arm/cpus.yaml
> index 14cd727d3c4b..a6ff8cb3db1e 100644
> --- a/Documentation/devicetree/bindings/arm/cpus.yaml
> +++ b/Documentation/devicetree/bindings/arm/cpus.yaml
> @@ -176,6 +176,7 @@ properties:
> oneOf:
> # On ARM v8 64-bit this property is required
> - enum:
> + - apple
> - psci
> - spin-table
> # On ARM 32-bit systems this property is optional

This uses a very generic identifier for doing something that may
be very specific to a particular SoC generation. It's going to be hard
to decide what the right abstraction will be for long-term maintenance,
so I'd recommend starting with a boot loader that implements
spin-table for secondary startup, and getting back to this after more
of the basic stuff works.

> +static int cpu_apple_start_prepare(unsigned int cpu)
> +{
> + struct device_node *node;
> + struct cpu_apple_start_info *info;
> +
> + info = per_cpu_ptr(&cpu_apple_start_info, cpu);
> +
> + if (info->pmgr_start && info->cputrc_rvbar && info->dbg_unlock)
> + return 0;
> +
> + node = of_find_compatible_node(NULL, NULL, "apple,startcpu");
> + if (!node) {
> + pr_err("%s: missing startcpu node in device tree.\n", __func__);
> + return -EINVAL;
> + }

Where is the binding documentation for this? The way you do a separate
of_iomap() for each CPU suggests that this is not a great binding to
start with. Are these perhaps just individual registers within a larger IP
block in the end?

Arnd

\
 
 \ /
  Last update: 2021-01-21 12:21    [W:0.272 / U:0.572 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site