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Subject[PATCH v2 1/5] ARM: introduce CPU_METHOD_OF_DECLARE_SETUP()
Date
The CPU_METHOD_OF_DECLARE() macro allows methods for assigning
SMP/hotplug operations to CPUS to be defined using device tree,
without the need for machine-dependent code.

And although it allows the *method* to be specified, it does *not*
allow any parameterization of that method. For example, there is no
efficient way to define a machine-specific address or other
property one might want to define for secondary CPUs.

Define a new of_cpu_method->setup() function, which (if defined) is
called for nodes found having a matching "enable-method" property.
The matching node is supplied as the function's argument, allowing
additional required information to be extracted from that node.
A new macro CPU_METHOD_OF_DECLARE_SETUP() allows a setup method
to be supplied when a method is declared.

Extend the interface for set_smp_ops_by_method() so that it can
return a negative error code to allow DT parsing errors to be
reported by the setup function.

(Note that only the first "cpu" (or "cpus") node having a matching
method is used by set_smp_ops_by_method(); this logic is not
changed.)

Signed-off-by: Alex Elder <elder@linaro.org>
---
arch/arm/include/asm/smp.h | 10 ++++++++--
arch/arm/kernel/devtree.c | 31 +++++++++++++++++++++++++------
2 files changed, 33 insertions(+), 8 deletions(-)

diff --git a/arch/arm/include/asm/smp.h b/arch/arm/include/asm/smp.h
index 2ec765c..ab4a5a9 100644
--- a/arch/arm/include/asm/smp.h
+++ b/arch/arm/include/asm/smp.h
@@ -115,15 +115,21 @@ struct smp_operations {
#endif
};

+struct device_node;
struct of_cpu_method {
const char *method;
+ int (*setup)(struct device_node *node);
struct smp_operations *ops;
};

-#define CPU_METHOD_OF_DECLARE(name, _method, _ops) \
+#define CPU_METHOD_OF_DECLARE_SETUP(name, _method, _setup, _ops) \
static const struct of_cpu_method __cpu_method_of_table_##name \
__used __section(__cpu_method_of_table) \
- = { .method = _method, .ops = _ops }
+ = { .method = _method, .setup = _setup, .ops = _ops }
+
+#define CPU_METHOD_OF_DECLARE(name, _method, _ops) \
+ CPU_METHOD_OF_DECLARE_SETUP(name, _method, NULL, _ops)
+
/*
* set platform specific SMP operations
*/
diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
index c7419a5..1a0cca3 100644
--- a/arch/arm/kernel/devtree.c
+++ b/arch/arm/kernel/devtree.c
@@ -76,11 +76,18 @@ static int __init set_smp_ops_by_method(struct device_node *node)
if (of_property_read_string(node, "enable-method", &method))
return 0;

- for (; m < __cpu_method_of_table_end; m++)
+ for (; m < __cpu_method_of_table_end; m++) {
if (!strcmp(m->method, method)) {
- smp_set_ops(m->ops);
- return 1;
+ int ret = 0;
+
+ if (m->setup)
+ ret = m->setup(node);
+ if (!ret)
+ smp_set_ops(m->ops);
+
+ return ret ? ret : 1;
}
+ }

return 0;
}
@@ -181,16 +188,28 @@ void __init arm_dt_init_cpu_maps(void)

tmp_map[i] = hwid;

- if (!found_method)
+ if (!found_method) {
found_method = set_smp_ops_by_method(cpu);
+ if (WARN(found_method < 0,
+ "error %d getting enable-method for "
+ "DT /cpu %u\n", found_method, cpuidx)) {
+ return;
+ }
+ }
}

/*
* Fallback to an enable-method in the cpus node if nothing found in
* a cpu node.
*/
- if (!found_method)
- set_smp_ops_by_method(cpus);
+ if (!found_method) {
+ found_method = set_smp_ops_by_method(cpus);
+ if (WARN(found_method < 0,
+ "error %d getting enable-method for "
+ "DT /cpus node\n", found_method)) {
+ return;
+ }
+ }

if (!bootcpu_valid) {
pr_warn("DT missing boot CPU MPIDR[23:0], fall back to default cpu_logical_map\n");
--
1.7.9.5


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