1 files changed, 148 insertions, 0 deletions

diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c
new file mode 100644
index 000000000000..1040c00405d0
--- /dev/null
+++ b/arch/arm/kernel/topology.c
@@ -0,0 +1,148 @@
+/*
+ * arch/arm/kernel/topology.c
+ *
+ * Copyright (C) 2011 Linaro Limited.
+ * Written by: Vincent Guittot
+ *
+ * based on arch/sh/kernel/topology.c
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/cpu.h>
+#include <linux/cpumask.h>
+#include <linux/init.h>
+#include <linux/percpu.h>
+#include <linux/node.h>
+#include <linux/nodemask.h>
+#include <linux/sched.h>
+
+#include <asm/cputype.h>
+#include <asm/topology.h>
+
+#define MPIDR_SMP_BITMASK (0x3 << 30)
+#define MPIDR_SMP_VALUE (0x2 << 30)
+
+#define MPIDR_MT_BITMASK (0x1 << 24)
+
+/*
+ * These masks reflect the current use of the affinity levels.
+ * The affinity level can be up to 16 bits according to ARM ARM
+ */
+
+#define MPIDR_LEVEL0_MASK 0x3
+#define MPIDR_LEVEL0_SHIFT 0
+
+#define MPIDR_LEVEL1_MASK 0xF
+#define MPIDR_LEVEL1_SHIFT 8
+
+#define MPIDR_LEVEL2_MASK 0xFF
+#define MPIDR_LEVEL2_SHIFT 16
+
+struct cputopo_arm cpu_topology[NR_CPUS];
+
+const struct cpumask *cpu_coregroup_mask(unsigned int cpu)
+{
+        return &cpu_topology[cpu].core_sibling;
+}
+
+/*
+ * store_cpu_topology is called at boot when only one cpu is running
+ * and with the mutex cpu_hotplug.lock locked, when several cpus have booted,
+ * which prevents simultaneous write access to cpu_topology array
+ */
+void store_cpu_topology(unsigned int cpuid)
+{
+        struct cputopo_arm *cpuid_topo = &cpu_topology[cpuid];
+        unsigned int mpidr;
+        unsigned int cpu;
+
+        /* If the cpu topology has been already set, just return */
+        if (cpuid_topo->core_id != -1)
+                return;
+
+        mpidr = read_cpuid_mpidr();
+
+        /* create cpu topology mapping */
+        if ((mpidr & MPIDR_SMP_BITMASK) == MPIDR_SMP_VALUE) {
+                /*
+                 * This is a multiprocessor system
+                 * multiprocessor format & multiprocessor mode field are set
+                 */
+
+                if (mpidr & MPIDR_MT_BITMASK) {
+                        /* core performance interdependency */
+                        cpuid_topo->thread_id = (mpidr >> MPIDR_LEVEL0_SHIFT)
+                                & MPIDR_LEVEL0_MASK;
+                        cpuid_topo->core_id = (mpidr >> MPIDR_LEVEL1_SHIFT)
+                                & MPIDR_LEVEL1_MASK;
+                        cpuid_topo->socket_id = (mpidr >> MPIDR_LEVEL2_SHIFT)
+                                & MPIDR_LEVEL2_MASK;
+                } else {
+                        /* largely independent cores */
+                        cpuid_topo->thread_id = -1;
+                        cpuid_topo->core_id = (mpidr >> MPIDR_LEVEL0_SHIFT)
+                                & MPIDR_LEVEL0_MASK;
+                        cpuid_topo->socket_id = (mpidr >> MPIDR_LEVEL1_SHIFT)
+                                & MPIDR_LEVEL1_MASK;
+                }
+        } else {
+                /*
+                 * This is an uniprocessor system
+                 * we are in multiprocessor format but uniprocessor system
+                 * or in the old uniprocessor format
+                 */
+                cpuid_topo->thread_id = -1;
+                cpuid_topo->core_id = 0;
+                cpuid_topo->socket_id = -1;
+        }
+
+        /* update core and thread sibling masks */
+        for_each_possible_cpu(cpu) {
+                struct cputopo_arm *cpu_topo = &cpu_topology[cpu];
+
+                if (cpuid_topo->socket_id == cpu_topo->socket_id) {
+                        cpumask_set_cpu(cpuid, &cpu_topo->core_sibling);
+                        if (cpu != cpuid)
+                                cpumask_set_cpu(cpu,
+                                        &cpuid_topo->core_sibling);
+
+                        if (cpuid_topo->core_id == cpu_topo->core_id) {
+                                cpumask_set_cpu(cpuid,
+                                        &cpu_topo->thread_sibling);
+                                if (cpu != cpuid)
+                                        cpumask_set_cpu(cpu,
+                                                &cpuid_topo->thread_sibling);
+                        }
+                }
+        }
+        smp_wmb();
+
+        printk(KERN_INFO "CPU%u: thread %d, cpu %d, socket %d, mpidr %x\n",
+                cpuid, cpu_topology[cpuid].thread_id,
+                cpu_topology[cpuid].core_id,
+                cpu_topology[cpuid].socket_id, mpidr);
+}
+
+/*
+ * init_cpu_topology is called at boot when only one cpu is running
+ * which prevent simultaneous write access to cpu_topology array
+ */
+void init_cpu_topology(void)
+{
+        unsigned int cpu;
+
+        /* init core mask */
+        for_each_possible_cpu(cpu) {
+                struct cputopo_arm *cpu_topo = &(cpu_topology[cpu]);
+
+                cpu_topo->thread_id = -1;
+                cpu_topo->core_id =  -1;
+                cpu_topo->socket_id = -1;
+                cpumask_clear(&cpu_topo->core_sibling);
+                cpumask_clear(&cpu_topo->thread_sibling);
+        }
+        smp_wmb();
+}