ARM: 6391/1: ux500: add CPU hotplug support

Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Sundar Iyer <sundar.iyer@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

3 files changed, 78 insertions, 0 deletions

diff --git a/arch/arm/mach-ux500/Makefile b/arch/arm/mach-ux500/Makefile
index 009731864399..bb3e74e6ab36 100644
--- a/arch/arm/mach-ux500/Makefile
+++ b/arch/arm/mach-ux500/Makefile
@@ -8,4 +8,5 @@ obj-$(CONFIG_UX500_SOC_DB8500)	+= cpu-db8500.o devices-db8500.o prcmu.o
 obj-$(CONFIG_MACH_U8500_MOP)    += board-mop500.o board-mop500-sdi.o
 obj-$(CONFIG_MACH_U5500)        += board-u5500.o
 obj-$(CONFIG_SMP)               += platsmp.o headsmp.o
+obj-$(CONFIG_HOTPLUG_CPU)       += hotplug.o
 obj-$(CONFIG_LOCAL_TIMERS)      += localtimer.o
diff --git a/arch/arm/mach-ux500/hotplug.c b/arch/arm/mach-ux500/hotplug.c
new file mode 100644
index 000000000000..b782a03024be
--- /dev/null
+++ b/arch/arm/mach-ux500/hotplug.c
@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) STMicroelectronics 2009
+ * Copyright (C) ST-Ericsson SA 2010
+ *
+ * License Terms: GNU General Public License v2
+ *      Based on ARM realview platform
+ *
+ * Author: Sundar Iyer <sundar.iyer@stericsson.com>
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/smp.h>
+#include <linux/completion.h>
+
+#include <asm/cacheflush.h>
+
+extern volatile int pen_release;
+
+static DECLARE_COMPLETION(cpu_killed);
+
+static inline void platform_do_lowpower(unsigned int cpu)
+{
+        flush_cache_all();
+
+        /* we put the platform to just WFI */
+        for (;;) {
+                __asm__ __volatile__("dsb\n\t" "wfi\n\t"
+                                : : : "memory");
+                if (pen_release == cpu) {
+                        /*
+                         * OK, proper wakeup, we're done
+                         */
+                        break;
+                }
+        }
+}
+
+int platform_cpu_kill(unsigned int cpu)
+{
+        return wait_for_completion_timeout(&cpu_killed, 5000);
+}
+
+/*
+ * platform-specific code to shutdown a CPU
+ *
+ * Called with IRQs disabled
+ */
+void platform_cpu_die(unsigned int cpu)
+{
+#ifdef DEBUG
+        unsigned int this_cpu = hard_smp_processor_id();
+
+        if (cpu != this_cpu) {
+                printk(KERN_CRIT "Eek! platform_cpu_die running on %u, should be %u\n",
+                           this_cpu, cpu);
+                BUG();
+        }
+#endif
+
+        printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
+        complete(&cpu_killed);
+
+        /* directly enter low power state, skipping secure registers */
+        platform_do_lowpower(cpu);
+}
+
+int platform_cpu_disable(unsigned int cpu)
+{
+        /*
+         * we don't allow CPU 0 to be shutdown (it is still too special
+         * e.g. clock tick interrupts)
+         */
+        return cpu == 0 ? -EPERM : 0;
+}
diff --git a/arch/arm/mach-ux500/platsmp.c b/arch/arm/mach-ux500/platsmp.c
index 438ef16aec90..9e4c678de785 100644
--- a/arch/arm/mach-ux500/platsmp.c
+++ b/arch/arm/mach-ux500/platsmp.c
@@ -78,6 +78,8 @@ int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
         __cpuc_flush_dcache_area((void *)&pen_release, sizeof(pen_release));
         outer_clean_range(__pa(&pen_release), __pa(&pen_release) + 1);
 
+        smp_cross_call(cpumask_of(cpu));
+
         timeout = jiffies + (1 * HZ);
         while (time_before(jiffies, timeout)) {
                 if (pen_release == -1)