5 files changed, 159 insertions, 51 deletions

diff --git a/arch/arm/mach-vexpress/Makefile b/arch/arm/mach-vexpress/Makefile
index 1b71b77ade22..2c0ac7de2814 100644
--- a/arch/arm/mach-vexpress/Makefile
+++ b/arch/arm/mach-vexpress/Makefile
@@ -5,4 +5,5 @@
 obj-y                                   := v2m.o
 obj-$(CONFIG_ARCH_VEXPRESS_CA9X4)       += ct-ca9x4.o
 obj-$(CONFIG_SMP)                       += platsmp.o headsmp.o
+obj-$(CONFIG_HOTPLUG_CPU)               += hotplug.o
 obj-$(CONFIG_LOCAL_TIMERS)              += localtimer.o
diff --git a/arch/arm/mach-vexpress/ct-ca9x4.c b/arch/arm/mach-vexpress/ct-ca9x4.c
index 26a02eb57571..f4455e3ed6a4 100644
--- a/arch/arm/mach-vexpress/ct-ca9x4.c
+++ b/arch/arm/mach-vexpress/ct-ca9x4.c
@@ -53,7 +53,9 @@ static struct map_desc ct_ca9x4_io_desc[] __initdata = {
 
 static void __init ct_ca9x4_map_io(void)
 {
+#ifdef CONFIG_LOCAL_TIMERS
         twd_base = MMIO_P2V(A9_MPCORE_TWD);
+#endif
         v2m_map_io(ct_ca9x4_io_desc, ARRAY_SIZE(ct_ca9x4_io_desc));
 }
 
diff --git a/arch/arm/mach-vexpress/hotplug.c b/arch/arm/mach-vexpress/hotplug.c
new file mode 100644
index 000000000000..ea4cbfb90a66
--- /dev/null
+++ b/arch/arm/mach-vexpress/hotplug.c
@@ -0,0 +1,128 @@
+/*
+ *  linux/arch/arm/mach-realview/hotplug.c
+ *
+ *  Copyright (C) 2002 ARM Ltd.
+ *  All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/smp.h>
+
+#include <asm/cacheflush.h>
+
+extern volatile int pen_release;
+
+static inline void cpu_enter_lowpower(void)
+{
+        unsigned int v;
+
+        flush_cache_all();
+        asm volatile(
+                "mcr    p15, 0, %1, c7, c5, 0\n"
+        "       mcr     p15, 0, %1, c7, c10, 4\n"
+        /*
+         * Turn off coherency
+         */
+        "       mrc     p15, 0, %0, c1, c0, 1\n"
+        "       bic     %0, %0, %3\n"
+        "       mcr     p15, 0, %0, c1, c0, 1\n"
+        "       mrc     p15, 0, %0, c1, c0, 0\n"
+        "       bic     %0, %0, %2\n"
+        "       mcr     p15, 0, %0, c1, c0, 0\n"
+          : "=&r" (v)
+          : "r" (0), "Ir" (CR_C), "Ir" (0x40)
+          : "cc");
+}
+
+static inline void cpu_leave_lowpower(void)
+{
+        unsigned int v;
+
+        asm volatile(
+                "mrc    p15, 0, %0, c1, c0, 0\n"
+        "       orr     %0, %0, %1\n"
+        "       mcr     p15, 0, %0, c1, c0, 0\n"
+        "       mrc     p15, 0, %0, c1, c0, 1\n"
+        "       orr     %0, %0, %2\n"
+        "       mcr     p15, 0, %0, c1, c0, 1\n"
+          : "=&r" (v)
+          : "Ir" (CR_C), "Ir" (0x40)
+          : "cc");
+}
+
+static inline void platform_do_lowpower(unsigned int cpu, int *spurious)
+{
+        /*
+         * there is no power-control hardware on this platform, so all
+         * we can do is put the core into WFI; this is safe as the calling
+         * code will have already disabled interrupts
+         */
+        for (;;) {
+                /*
+                 * here's the WFI
+                 */
+                asm(".word      0xe320f003\n"
+                    :
+                    :
+                    : "memory", "cc");
+
+                if (pen_release == cpu) {
+                        /*
+                         * OK, proper wakeup, we're done
+                         */
+                        break;
+                }
+
+                /*
+                 * Getting here, means that we have come out of WFI without
+                 * having been woken up - this shouldn't happen
+                 *
+                 * Just note it happening - when we're woken, we can report
+                 * its occurrence.
+                 */
+                (*spurious)++;
+        }
+}
+
+int platform_cpu_kill(unsigned int cpu)
+{
+        return 1;
+}
+
+/*
+ * platform-specific code to shutdown a CPU
+ *
+ * Called with IRQs disabled
+ */
+void platform_cpu_die(unsigned int cpu)
+{
+        int spurious = 0;
+
+        /*
+         * we're ready for shutdown now, so do it
+         */
+        cpu_enter_lowpower();
+        platform_do_lowpower(cpu, &spurious);
+
+        /*
+         * bring this CPU back into the world of cache
+         * coherency, and then restore interrupts
+         */
+        cpu_leave_lowpower();
+
+        if (spurious)
+                pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious);
+}
+
+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-vexpress/include/mach/smp.h b/arch/arm/mach-vexpress/include/mach/smp.h
index 5a6da4fd247e..4c05e4a9713a 100644
--- a/arch/arm/mach-vexpress/include/mach/smp.h
+++ b/arch/arm/mach-vexpress/include/mach/smp.h
@@ -2,13 +2,12 @@
 #define __MACH_SMP_H
 
 #include <asm/hardware/gic.h>
-#include <asm/smp_mpidr.h>
 
 /*
  * We use IRQ1 as the IPI
  */
-static inline void smp_cross_call(const struct cpumask *mask)
+static inline void smp_cross_call(const struct cpumask *mask, int ipi)
 {
-        gic_raise_softirq(mask, 1);
+        gic_raise_softirq(mask, ipi);
 }
 #endif
diff --git a/arch/arm/mach-vexpress/platsmp.c b/arch/arm/mach-vexpress/platsmp.c
index 670970699ba9..8ce9fef29555 100644
--- a/arch/arm/mach-vexpress/platsmp.c
+++ b/arch/arm/mach-vexpress/platsmp.c
@@ -17,7 +17,6 @@
 #include <linux/io.h>
 
 #include <asm/cacheflush.h>
-#include <asm/localtimer.h>
 #include <asm/smp_scu.h>
 #include <asm/unified.h>
 
@@ -35,6 +34,19 @@ extern void vexpress_secondary_startup(void);
  */
 volatile int __cpuinitdata pen_release = -1;
 
+/*
+ * Write pen_release in a way that is guaranteed to be visible to all
+ * observers, irrespective of whether they're taking part in coherency
+ * or not.  This is necessary for the hotplug code to work reliably.
+ */
+static void write_pen_release(int val)
+{
+        pen_release = val;
+        smp_wmb();
+        __cpuc_flush_dcache_area((void *)&pen_release, sizeof(pen_release));
+        outer_clean_range(__pa(&pen_release), __pa(&pen_release + 1));
+}
+
 static void __iomem *scu_base_addr(void)
 {
         return MMIO_P2V(A9_MPCORE_SCU);
@@ -44,8 +56,6 @@ static DEFINE_SPINLOCK(boot_lock);
 
 void __cpuinit platform_secondary_init(unsigned int cpu)
 {
-        trace_hardirqs_off();
-
         /*
          * if any interrupts are already enabled for the primary
          * core (e.g. timer irq), then they will not have been enabled
@@ -57,8 +67,7 @@ void __cpuinit platform_secondary_init(unsigned int cpu)
          * let the primary processor know we're out of the
          * pen, then head off into the C entry point
          */
-        pen_release = -1;
-        smp_wmb();
+        write_pen_release(-1);
 
         /*
          * Synchronise with the boot thread.
@@ -83,16 +92,14 @@ int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
          * since we haven't sent them a soft interrupt, they shouldn't
          * be there.
          */
-        pen_release = cpu;
-        __cpuc_flush_dcache_area((void *)&pen_release, sizeof(pen_release));
-        outer_clean_range(__pa(&pen_release), __pa(&pen_release + 1));
+        write_pen_release(cpu);
 
         /*
          * Send the secondary CPU a soft interrupt, thereby causing
          * the boot monitor to read the system wide flags register,
          * and branch to the address found there.
          */
-        smp_cross_call(cpumask_of(cpu));
+        smp_cross_call(cpumask_of(cpu), 1);
 
         timeout = jiffies + (1 * HZ);
         while (time_before(jiffies, timeout)) {
@@ -124,13 +131,6 @@ void __init smp_init_cpus(void)
         ncores = scu_base ? scu_get_core_count(scu_base) : 1;
 
         /* sanity check */
-        if (ncores == 0) {
-                printk(KERN_ERR
-                       "vexpress: strange CM count of 0? Default to 1\n");
-
-                ncores = 1;
-        }
-
         if (ncores > NR_CPUS) {
                 printk(KERN_WARNING
                        "vexpress: no. of cores (%d) greater than configured "
@@ -143,20 +143,10 @@ void __init smp_init_cpus(void)
                 set_cpu_possible(i, true);
 }
 
-void __init smp_prepare_cpus(unsigned int max_cpus)
+void __init platform_smp_prepare_cpus(unsigned int max_cpus)
 {
-        unsigned int ncores = num_possible_cpus();
-        unsigned int cpu = smp_processor_id();
         int i;
 
-        smp_store_cpu_info(cpu);
-
-        /*
-         * are we trying to boot more cores than exist?
-         */
-        if (max_cpus > ncores)
-                max_cpus = ncores;
-
         /*
          * Initialise the present map, which describes the set of CPUs
          * actually populated at the present time.
@@ -164,27 +154,15 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
         for (i = 0; i < max_cpus; i++)
                 set_cpu_present(i, true);
 
+        scu_enable(scu_base_addr());
+
         /*
-         * Initialise the SCU if there are more than one CPU and let
-         * them know where to start.
+         * Write the address of secondary startup into the
+         * system-wide flags register. The boot monitor waits
+         * until it receives a soft interrupt, and then the
+         * secondary CPU branches to this address.
          */
-        if (max_cpus > 1) {
-                /*
-                 * Enable the local timer or broadcast device for the
-                 * boot CPU, but only if we have more than one CPU.
-                 */
-                percpu_timer_setup();
-
-                scu_enable(scu_base_addr());
-
-                /*
-                 * Write the address of secondary startup into the
-                 * system-wide flags register. The boot monitor waits
-                 * until it receives a soft interrupt, and then the
-                 * secondary CPU branches to this address.
-                 */
-                writel(~0, MMIO_P2V(V2M_SYS_FLAGSCLR));
-                writel(BSYM(virt_to_phys(vexpress_secondary_startup)),
-                        MMIO_P2V(V2M_SYS_FLAGSSET));
-        }
+        writel(~0, MMIO_P2V(V2M_SYS_FLAGSCLR));
+        writel(BSYM(virt_to_phys(vexpress_secondary_startup)),
+                MMIO_P2V(V2M_SYS_FLAGSSET));
 }