3 files changed, 53 insertions, 110 deletions

diff --git a/arch/arm/mach-realview/hotplug.c b/arch/arm/mach-realview/hotplug.c
index f95521a5e5ce..a87523d095e6 100644
--- a/arch/arm/mach-realview/hotplug.c
+++ b/arch/arm/mach-realview/hotplug.c
@@ -11,14 +11,11 @@
 #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 cpu_enter_lowpower(void)
 {
         unsigned int v;
@@ -34,10 +31,10 @@ static inline void cpu_enter_lowpower(void)
         "       bic     %0, %0, #0x20\n"
         "       mcr     p15, 0, %0, c1, c0, 1\n"
         "       mrc     p15, 0, %0, c1, c0, 0\n"
-        "       bic     %0, %0, #0x04\n"
+        "       bic     %0, %0, %2\n"
         "       mcr     p15, 0, %0, c1, c0, 0\n"
           : "=&r" (v)
-          : "r" (0)
+          : "r" (0), "Ir" (CR_C)
           : "cc");
 }
 
@@ -46,17 +43,17 @@ static inline void cpu_leave_lowpower(void)
         unsigned int v;
 
         asm volatile(   "mrc    p15, 0, %0, c1, c0, 0\n"
-        "       orr     %0, %0, #0x04\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, #0x20\n"
         "       mcr     p15, 0, %0, c1, c0, 1\n"
           : "=&r" (v)
-          :
+          : "Ir" (CR_C)
           : "cc");
 }
 
-static inline void platform_do_lowpower(unsigned int cpu)
+static inline void platform_do_lowpower(unsigned int cpu, int *spurious)
 {
         /*
          * there is no power-control hardware on this platform, so all
@@ -80,22 +77,19 @@ static inline void platform_do_lowpower(unsigned int cpu)
                 }
 
                 /*
-                 * getting here, means that we have come out of WFI without
+                 * Getting here, means that we have come out of WFI without
                  * having been woken up - this shouldn't happen
                  *
-                 * The trouble is, letting people know about this is not really
-                 * possible, since we are currently running incoherently, and
-                 * therefore cannot safely call printk() or anything else
+                 * Just note it happening - when we're woken, we can report
+                 * its occurrence.
                  */
-#ifdef DEBUG
-                printk("CPU%u: spurious wakeup call\n", cpu);
-#endif
+                (*spurious)++;
         }
 }
 
 int platform_cpu_kill(unsigned int cpu)
 {
-        return wait_for_completion_timeout(&cpu_killed, 5000);
+        return 1;
 }
 
 /*
@@ -105,30 +99,22 @@ int platform_cpu_kill(unsigned int cpu)
  */
 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);
+        int spurious = 0;
 
         /*
          * we're ready for shutdown now, so do it
          */
         cpu_enter_lowpower();
-        platform_do_lowpower(cpu);
+        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)
diff --git a/arch/arm/mach-realview/include/mach/smp.h b/arch/arm/mach-realview/include/mach/smp.h
index d3cd265cb058..c8221b38ee7c 100644
--- a/arch/arm/mach-realview/include/mach/smp.h
+++ b/arch/arm/mach-realview/include/mach/smp.h
@@ -2,14 +2,13 @@
 #define ASMARM_ARCH_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-realview/platsmp.c b/arch/arm/mach-realview/platsmp.c
index 009265818d55..bb8d6c4e4315 100644
--- a/arch/arm/mach-realview/platsmp.c
+++ b/arch/arm/mach-realview/platsmp.c
@@ -19,7 +19,6 @@
 #include <asm/cacheflush.h>
 #include <mach/hardware.h>
 #include <asm/mach-types.h>
-#include <asm/localtimer.h>
 #include <asm/unified.h>
 
 #include <mach/board-eb.h>
@@ -37,6 +36,19 @@ extern void realview_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)
 {
         if (machine_is_realview_eb_mp())
@@ -50,20 +62,10 @@ static void __iomem *scu_base_addr(void)
                 return (void __iomem *)0;
 }
 
-static inline unsigned int get_core_count(void)
-{
-        void __iomem *scu_base = scu_base_addr();
-        if (scu_base)
-                return scu_get_core_count(scu_base);
-        return 1;
-}
-
 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
@@ -75,8 +77,7 @@ 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.
@@ -103,20 +104,14 @@ int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
          * Note that "pen_release" is the hardware CPU ID, whereas
          * "cpu" is Linux's internal ID.
          */
-        pen_release = cpu;
-        flush_cache_all();
+        write_pen_release(cpu);
 
         /*
-         * XXX
-         *
-         * This is a later addition to the booting protocol: the
-         * bootMonitor now puts secondary cores into WFI, so
-         * poke_milo() no longer gets the cores moving; we need
-         * to send a soft interrupt to wake the secondary core.
-         * Use smp_cross_call() for this, since there's little
-         * point duplicating the code here
+         * 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)) {
@@ -136,48 +131,18 @@ int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
         return pen_release != -1 ? -ENOSYS : 0;
 }
 
-static void __init poke_milo(void)
-{
-        /* nobody is to be released from the pen yet */
-        pen_release = -1;
-
-        /*
-         * Write the address of secondary startup into the system-wide flags
-         * register. The BootMonitor waits for this register to become
-         * non-zero.
-         */
-        __raw_writel(BSYM(virt_to_phys(realview_secondary_startup)),
-                     __io_address(REALVIEW_SYS_FLAGSSET));
-
-        mb();
-}
-
 /*
  * Initialise the CPU possible map early - this describes the CPUs
  * which may be present or become present in the system.
  */
 void __init smp_init_cpus(void)
 {
-        unsigned int i, ncores = get_core_count();
+        void __iomem *scu_base = scu_base_addr();
+        unsigned int i, ncores;
 
-        for (i = 0; i < ncores; i++)
-                set_cpu_possible(i, true);
-}
-
-void __init smp_prepare_cpus(unsigned int max_cpus)
-{
-        unsigned int ncores = get_core_count();
-        unsigned int cpu = smp_processor_id();
-        int i;
+        ncores = scu_base ? scu_get_core_count(scu_base) : 1;
 
         /* sanity check */
-        if (ncores == 0) {
-                printk(KERN_ERR
-                       "Realview: strange CM count of 0? Default to 1\n");
-
-                ncores = 1;
-        }
-
         if (ncores > NR_CPUS) {
                 printk(KERN_WARNING
                        "Realview: no. of cores (%d) greater than configured "
@@ -186,13 +151,13 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
                 ncores = NR_CPUS;
         }
 
-        smp_store_cpu_info(cpu);
+        for (i = 0; i < ncores; i++)
+                set_cpu_possible(i, true);
+}
 
-        /*
-         * are we trying to boot more cores than exist?
-         */
-        if (max_cpus > ncores)
-                max_cpus = ncores;
+void __init platform_smp_prepare_cpus(unsigned int max_cpus)
+{
+        int i;
 
         /*
          * Initialise the present map, which describes the set of CPUs
@@ -201,21 +166,14 @@ 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. Note that, on modern versions of
-         * MILO, the "poke" doesn't actually do anything until each
-         * individual core is sent a soft interrupt to get it out of
-         * WFI
+         * Write the address of secondary startup into the
+         * system-wide flags register. The BootMonitor 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());
-                poke_milo();
-        }
+        __raw_writel(BSYM(virt_to_phys(realview_secondary_startup)),
+                     __io_address(REALVIEW_SYS_FLAGSSET));
 }