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>

diff --git a/arch/arm/mach-ux500/Makefile b/arch/arm/mach-ux500/Makefile
index 009731864399cee54ae18f7a0ebc7e1d39583c40..bb3e74e6ab362f5cf087ee5fb2e72f2cb6bb8bfa 100644 (file)
--- 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 (file)
index 0000000..b782a03
--- /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 438ef16aec901e2e11a4d0b6ebb9b5bae165fb1b..9e4c678de78593a248c9010a4eb8e0edcb4cb4dc 100644 (file)
--- 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)