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authorStephen Boyd <sboyd@codeaurora.org>2013-10-30 18:21:09 -0700
committerKumar Gala <galak@codeaurora.org>2014-02-11 15:00:37 -0600
commit6c3ff8b11a16ec69199ab85b74a5fae6d9c59db7 (patch)
tree79bf0dffed2a312578dd2a75048f6d65d21a6e8d /arch/arm/kernel/devtree.c
parentcf1e8f0cd665e2a9966d2bee4e11ecc0938ff166 (diff)
downloadlinux-stericsson-6c3ff8b11a16ec69199ab85b74a5fae6d9c59db7.tar.gz
ARM: Introduce CPU_METHOD_OF_DECLARE() for cpu hotplug/smp
The goal of multi-platform kernels is to remove the need for mach directories and machine descriptors. To further that goal, introduce CPU_METHOD_OF_DECLARE() to allow cpu hotplug/smp support to be separated from the machine descriptors. Implementers should specify an enable-method property in their cpus node and then implement a matching set of smp_ops in their hotplug/smp code, wiring it up with the CPU_METHOD_OF_DECLARE() macro. When the kernel is compiled we'll collect all the enable-method smp_ops into one section for use at boot. At boot time we'll look for an enable-method in each cpu node and try to match that against all known CPU enable methods in the kernel. If there are no enable-methods in the cpu nodes we fallback to the cpus node and try to use any enable-method found there. If that doesn't work we fall back to the old way of using the machine descriptor. Acked-by: Mark Rutland <mark.rutland@arm.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: <devicetree@vger.kernel.org> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Kumar Gala <galak@codeaurora.org>
Diffstat (limited to 'arch/arm/kernel/devtree.c')
-rw-r--r--arch/arm/kernel/devtree.c40
1 files changed, 40 insertions, 0 deletions
diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
index f751714d52c1..c7419a585ddc 100644
--- a/arch/arm/kernel/devtree.c
+++ b/arch/arm/kernel/devtree.c
@@ -18,6 +18,7 @@
#include <linux/of_fdt.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
+#include <linux/smp.h>
#include <asm/cputype.h>
#include <asm/setup.h>
@@ -63,6 +64,34 @@ void __init arm_dt_memblock_reserve(void)
}
}
+#ifdef CONFIG_SMP
+extern struct of_cpu_method __cpu_method_of_table_begin[];
+extern struct of_cpu_method __cpu_method_of_table_end[];
+
+static int __init set_smp_ops_by_method(struct device_node *node)
+{
+ const char *method;
+ struct of_cpu_method *m = __cpu_method_of_table_begin;
+
+ if (of_property_read_string(node, "enable-method", &method))
+ return 0;
+
+ for (; m < __cpu_method_of_table_end; m++)
+ if (!strcmp(m->method, method)) {
+ smp_set_ops(m->ops);
+ return 1;
+ }
+
+ return 0;
+}
+#else
+static inline int set_smp_ops_by_method(struct device_node *node)
+{
+ return 1;
+}
+#endif
+
+
/*
* arm_dt_init_cpu_maps - Function retrieves cpu nodes from the device tree
* and builds the cpu logical map array containing MPIDR values related to
@@ -79,6 +108,7 @@ void __init arm_dt_init_cpu_maps(void)
* read as 0.
*/
struct device_node *cpu, *cpus;
+ int found_method = 0;
u32 i, j, cpuidx = 1;
u32 mpidr = is_smp() ? read_cpuid_mpidr() & MPIDR_HWID_BITMASK : 0;
@@ -150,8 +180,18 @@ void __init arm_dt_init_cpu_maps(void)
}
tmp_map[i] = hwid;
+
+ if (!found_method)
+ found_method = set_smp_ops_by_method(cpu);
}
+ /*
+ * 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 (!bootcpu_valid) {
pr_warn("DT missing boot CPU MPIDR[23:0], fall back to default cpu_logical_map\n");
return;