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authorChen-Yu Tsai <wens@csie.org>2018-03-08 18:00:10 +0300
committerChen-Yu Tsai <wens@csie.org>2018-03-10 11:14:46 +0300
commit8591743f12636a247bdab56c8c355ea9686f2d97 (patch)
treed45c77e057e8a5994b4f69b9158c844a5b44badb /arch/arm/mach-sunxi
parentc161daea999b9b707d9ffde28ce978d14d5a1185 (diff)
downloadlinux-8591743f12636a247bdab56c8c355ea9686f2d97.tar.xz
ARM: sunxi: mc-smp: Use DT enable-method for sun9i A80 SMP
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>
Diffstat (limited to 'arch/arm/mach-sunxi')
-rw-r--r--arch/arm/mach-sunxi/mc_smp.c21
1 files changed, 20 insertions, 1 deletions
diff --git a/arch/arm/mach-sunxi/mc_smp.c b/arch/arm/mach-sunxi/mc_smp.c
index 9db6c4ed5861..86e90b038555 100644
--- a/arch/arm/mach-sunxi/mc_smp.c
+++ b/arch/arm/mach-sunxi/mc_smp.c
@@ -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())