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 <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
(cherry picked from commit e8765b265a69c83504afc6901d6e137b1811d1f0)
Signed-off-by: Mark Brown <broonie@linaro.org>

diff --git a/arch/arm64/include/asm/cpu_ops.h b/arch/arm64/include/asm/cpu_ops.h
index 67bc4fd83798c625993ca22bde489210fb98d83a..1a98dbfc4a5f36dc5f821993c674b1459c403dd4 100644 (file)
--- a/arch/arm64/include/asm/cpu_ops.h
+++ b/arch/arm64/include/asm/cpu_ops.h
@@ -44,6 +44,7 @@ struct cpu_operations {
 };
 
 extern const struct cpu_operations *cpu_ops[NR_CPUS];
-extern const struct cpu_operations * __init cpu_get_ops(const char *name);
+extern int __init cpu_read_ops(struct device_node *dn, int cpu);
+extern void __init cpu_read_bootcpu_ops(void);
 
 #endif /* ifndef __ASM_CPU_OPS_H */

diff --git a/arch/arm64/kernel/cpu_ops.c b/arch/arm64/kernel/cpu_ops.c
index e2652aadd9ea23055bf6dd60e64d73bd5d159013..aa0c9e78dbe139883f726be1221ed2ec74f3e017 100644 (file)
--- a/arch/arm64/kernel/cpu_ops.c
+++ b/arch/arm64/kernel/cpu_ops.c
@@ -17,6 +17,9 @@
  */
 
 #include <asm/cpu_ops.h>
+#include <asm/smp_plat.h>
+#include <linux/errno.h>
+#include <linux/of.h>
 #include <linux/string.h>
 
 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;
+               }
+       }
+}

diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index add6ea616843139ff81a65f26c344ed9e69fd66d..3dc5c2f7c6b1448a2378e433f6fb443762c646aa 100644 (file)
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -45,6 +45,7 @@
 #include <asm/cputype.h>
 #include <asm/elf.h>
 #include <asm/cputable.h>
+#include <asm/cpu_ops.h>
 #include <asm/sections.h>
 #include <asm/setup.h>
 #include <asm/smp_plat.h>
@@ -269,6 +270,7 @@ void __init setup_arch(char **cmdline_p)
        psci_init();
 
        cpu_logical_map(0) = read_cpuid_mpidr() & MPIDR_HWID_BITMASK;
+       cpu_read_bootcpu_ops();
 #ifdef CONFIG_SMP
        smp_init_cpus();
 #endif

diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 6e9779c878adb24199264c54349e8f6a2e6ab707..82eea4a18a853200e1a5bf3c063f803e209d312b 100644 (file)
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -188,7 +188,6 @@ static void (*smp_cross_call)(const struct cpumask *, unsigned int);
  */
 void __init smp_init_cpus(void)
 {
-       const char *enable_method;
        struct device_node *dn = NULL;
        unsigned int i, cpu = 1;
        bool bootcpu_valid = false;
@@ -259,23 +258,8 @@ void __init smp_init_cpus(void)
                if (cpu >= NR_CPUS)
                        goto next;
 
-               /*
-                * We currently support only the "spin-table" enable-method.
-                */
-               enable_method = of_get_property(dn, "enable-method", NULL);
-               if (!enable_method) {
-                       pr_err("%s: missing enable-method property\n",
-                               dn->full_name);
+               if (cpu_read_ops(dn, cpu) != 0)
                        goto next;
-               }
-
-               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);
-                       goto next;
-               }
 
                if (cpu_ops[cpu]->cpu_init(dn, cpu))
                        goto next;