From e8765b265a69c83504afc6901d6e137b1811d1f0 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Thu, 24 Oct 2013 20:30:17 +0100 Subject: arm64: read enable-method for CPU0 With the advent of CPU_HOTPLUG, the enable-method property for CPU0 may tells us something useful (i.e. how to hotplug it back on), so we must read it along with all the enable-method for all the other CPUs. Even on UP the enable-method may tell us useful information (e.g. if a core has some mechanism that might be usable for cpuidle), so we should always read it. This patch factors out the reading of the enable method, and ensures that CPU0's enable method is read regardless of whether the kernel is built with SMP support. Signed-off-by: Mark Rutland Signed-off-by: Catalin Marinas --- arch/arm64/kernel/cpu_ops.c | 54 ++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 53 insertions(+), 1 deletion(-) (limited to 'arch/arm64/kernel/cpu_ops.c') diff --git a/arch/arm64/kernel/cpu_ops.c b/arch/arm64/kernel/cpu_ops.c index e2652aadd9ea..aa0c9e78dbe1 100644 --- a/arch/arm64/kernel/cpu_ops.c +++ b/arch/arm64/kernel/cpu_ops.c @@ -17,6 +17,9 @@ */ #include +#include +#include +#include #include extern const struct cpu_operations smp_spin_table_ops; @@ -32,7 +35,7 @@ static const struct cpu_operations *supported_cpu_ops[] __initconst = { NULL, }; -const struct cpu_operations * __init cpu_get_ops(const char *name) +static const struct cpu_operations * __init cpu_get_ops(const char *name) { const struct cpu_operations **ops = supported_cpu_ops; @@ -45,3 +48,52 @@ const struct cpu_operations * __init cpu_get_ops(const char *name) return NULL; } + +/* + * Read a cpu's enable method from the device tree and record it in cpu_ops. + */ +int __init cpu_read_ops(struct device_node *dn, int cpu) +{ + const char *enable_method = of_get_property(dn, "enable-method", NULL); + if (!enable_method) { + /* + * The boot CPU may not have an enable method (e.g. when + * spin-table is used for secondaries). Don't warn spuriously. + */ + if (cpu != 0) + pr_err("%s: missing enable-method property\n", + dn->full_name); + return -ENOENT; + } + + cpu_ops[cpu] = cpu_get_ops(enable_method); + if (!cpu_ops[cpu]) { + pr_err("%s: invalid enable-method property: %s\n", + dn->full_name, enable_method); + return -EOPNOTSUPP; + } + + return 0; +} + +void __init cpu_read_bootcpu_ops(void) +{ + struct device_node *dn = NULL; + u64 mpidr = cpu_logical_map(0); + + while ((dn = of_find_node_by_type(dn, "cpu"))) { + u64 hwid; + const __be32 *prop; + + prop = of_get_property(dn, "reg", NULL); + if (!prop) + continue; + + hwid = of_read_number(prop, of_n_addr_cells(dn)); + if (hwid == mpidr) { + cpu_read_ops(dn, 0); + of_node_put(dn); + return; + } + } +} -- cgit v1.2.3