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ARM: sunxi: mc-smp: Use DT enable-method for sun9i A80 SMP

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Instead of having an early init function check the machine compatible
and installing multi-cluster SMP support for the A80 if it matches,
use a new cpu enable-method string. This makes the platform support
future proof in case anyone manages to add PSCI support.

The original init code for the SMP support is changed into the
.prepare_cpus callback in the smp_operations structure. Instead of
panicing when resources are missing like on some platforms, our code
merely guards against engaging SMP or CPU hotplug and returns an error.

Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
This commit is contained in:
Chen-Yu Tsai 2018-03-08 23:00:10 +08:00
parent c161daea99
commit 8591743f12
2 changed files with 21 additions and 1 deletions
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1
Documentation/devicetree/bindings/arm/cpus.txt
View File

@ -198,6 +198,7 @@ described below.
"actions,s500-smp"
"allwinner,sun6i-a31"
"allwinner,sun8i-a23"
"allwinner,sun9i-a80-smp"
"amlogic,meson8-smp"
"amlogic,meson8b-smp"
"arm,realview-smp"

21
arch/arm/mach-sunxi/mc_smp.c
View File

@ -690,7 +690,26 @@ static int __init sunxi_mc_smp_init(void)
struct resource res;
int ret;
if (!of_machine_is_compatible("allwinner,sun9i-a80"))
/*
* Don't bother checking the "cpus" node, as an enable-method
* property in that node is undocumented.
*/
node = of_cpu_device_node_get(0);
if (!node)
return -ENODEV;
/*
* We can't actually use the enable-method magic in the kernel.
* Our loopback / trampoline code uses the CPU suspend framework,
* which requires the identity mapping be available. It would not
* yet be available if we used the .init_cpus or .prepare_cpus
* callbacks in smp_operations, which we would use if we were to
* use CPU_METHOD_OF_DECLARE
*/
ret = of_property_match_string(node, "enable-method",
"allwinner,sun9i-a80-smp");
of_node_put(node);
if (ret)
return -ENODEV;
if (!sunxi_mc_smp_cpu_table_init())