2 files changed, 47 insertions, 0 deletions

diff --git a/arch/arm/mach-shmobile/include/mach/common.h b/arch/arm/mach-shmobile/include/mach/common.h
index 42761f4fb171..04209d5c0338 100644
--- a/arch/arm/mach-shmobile/include/mach/common.h
+++ b/arch/arm/mach-shmobile/include/mach/common.h
@@ -14,6 +14,8 @@ extern void shmobile_boot_scu(void);
 extern void shmobile_smp_scu_prepare_cpus(unsigned int max_cpus);
 extern int shmobile_smp_scu_boot_secondary(unsigned int cpu,
                                            struct task_struct *idle);
+extern void shmobile_smp_scu_cpu_die(unsigned int cpu);
+extern int shmobile_smp_scu_cpu_kill(unsigned int cpu);
 struct clk;
 extern int shmobile_clk_init(void);
 extern void shmobile_handle_irq_intc(struct pt_regs *);
diff --git a/arch/arm/mach-shmobile/platsmp-scu.c b/arch/arm/mach-shmobile/platsmp-scu.c
index 8f478e4d4964..7a0c066df686 100644
--- a/arch/arm/mach-shmobile/platsmp-scu.c
+++ b/arch/arm/mach-shmobile/platsmp-scu.c
@@ -7,9 +7,11 @@
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */
+#include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/smp.h>
+#include <asm/cacheflush.h>
 #include <asm/smp_plat.h>
 #include <asm/smp_scu.h>
 #include <mach/common.h>
@@ -29,3 +31,46 @@ int shmobile_smp_scu_boot_secondary(unsigned int cpu, struct task_struct *idle)
         /* do nothing for now */
         return 0;
 }
+
+#ifdef CONFIG_HOTPLUG_CPU
+void shmobile_smp_scu_cpu_die(unsigned int cpu)
+{
+        dsb();
+        flush_cache_all();
+
+        /* disable cache coherency */
+        scu_power_mode(shmobile_scu_base, SCU_PM_POWEROFF);
+
+        /* Endless loop until reset */
+        while (1)
+                cpu_do_idle();
+}
+
+static int shmobile_smp_scu_psr_core_disabled(int cpu)
+{
+        unsigned long mask = SCU_PM_POWEROFF << (cpu * 8);
+
+        if ((__raw_readl(shmobile_scu_base + 8) & mask) == mask)
+                return 1;
+
+        return 0;
+}
+
+int shmobile_smp_scu_cpu_kill(unsigned int cpu)
+{
+        int k;
+
+        /* this function is running on another CPU than the offline target,
+         * here we need wait for shutdown code in platform_cpu_die() to
+         * finish before asking SoC-specific code to power off the CPU core.
+         */
+        for (k = 0; k < 1000; k++) {
+                if (shmobile_smp_scu_psr_core_disabled(cpu))
+                        return 1;
+
+                mdelay(1);
+        }
+
+        return 0;
+}
+#endif