1 files changed, 101 insertions, 0 deletions

diff --git a/arch/arm/mach-spear/hotplug.c b/arch/arm/mach-spear/hotplug.c
new file mode 100644
index 000000000000..d97749c642ce
--- /dev/null
+++ b/arch/arm/mach-spear/hotplug.c
@@ -0,0 +1,101 @@
+/*
+ * linux/arch/arm/mach-spear13xx/hotplug.c
+ *
+ * Copyright (C) 2012 ST Microelectronics Ltd.
+ * Deepak Sikri <deepak.sikri@st.com>
+ *
+ * based upon linux/arch/arm/mach-realview/hotplug.c
+ *
+ * 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/cp15.h>
+#include <asm/smp_plat.h>
+
+static inline void cpu_enter_lowpower(void)
+{
+        unsigned int v;
+
+        asm volatile(
+        "       mcr     p15, 0, %1, c7, c5, 0\n"
+        "       dsb\n"
+        /*
+         * Turn off coherency
+         */
+        "       mrc     p15, 0, %0, c1, c0, 1\n"
+        "       bic     %0, %0, #0x20\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)
+        : "cc", "memory");
+}
+
+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, #0x20\n"
+        "       mcr     p15, 0, %0, c1, c0, 1\n"
+        : "=&r" (v)
+        : "Ir" (CR_C)
+        : "cc");
+}
+
+static inline void spear13xx_do_lowpower(unsigned int cpu, int *spurious)
+{
+        for (;;) {
+                wfi();
+
+                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)++;
+        }
+}
+
+/*
+ * platform-specific code to shutdown a CPU
+ *
+ * Called with IRQs disabled
+ */
+void __ref spear13xx_cpu_die(unsigned int cpu)
+{
+        int spurious = 0;
+
+        /*
+         * we're ready for shutdown now, so do it
+         */
+        cpu_enter_lowpower();
+        spear13xx_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);
+}