arm: zynq: Add hotplug support

Signed-off-by: Michal Simek <michal.simek@xilinx.com>

diff --git a/arch/arm/mach-zynq/Makefile b/arch/arm/mach-zynq/Makefile
index b595d22134ec356396544a671130162596605e1c..1b25d92ebf22c9d9bb513344138816568aef8212 100644 (file)
--- a/arch/arm/mach-zynq/Makefile
+++ b/arch/arm/mach-zynq/Makefile
@@ -4,4 +4,7 @@
 
 # Common support
 obj-y                          := common.o slcr.o
+CFLAGS_REMOVE_hotplug.o                =-march=armv6k
+CFLAGS_hotplug.o               =-Wa,-march=armv7-a -mcpu=cortex-a9
+obj-$(CONFIG_HOTPLUG_CPU)      += hotplug.o
 obj-$(CONFIG_SMP)              += headsmp.o platsmp.o

diff --git a/arch/arm/mach-zynq/common.h b/arch/arm/mach-zynq/common.h
index fd308f8b18d9782339fa3fcfaa71551a6b91a59c..fbbd0e21c404d5f98bc4c6bf5387df045ceaa66f 100644 (file)
--- a/arch/arm/mach-zynq/common.h
+++ b/arch/arm/mach-zynq/common.h
@@ -34,4 +34,7 @@ extern struct smp_operations zynq_smp_ops __initdata;
 extern void __iomem *zynq_slcr_base;
 extern void __iomem *zynq_scu_base;
 
+/* Hotplug */
+extern void zynq_platform_cpu_die(unsigned int cpu);
+
 #endif

diff --git a/arch/arm/mach-zynq/hotplug.c b/arch/arm/mach-zynq/hotplug.c
new file mode 100644 (file)
index 0000000..c89672b
--- /dev/null
+++ b/arch/arm/mach-zynq/hotplug.c
@@ -0,0 +1,104 @@
+/*
+ * Copyright (C) 2012-2013 Xilinx
+ *
+ * based on 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>
+#include <asm/cp15.h>
+#include "common.h"
+
+static inline void zynq_cpu_enter_lowpower(void)
+{
+       unsigned int v;
+
+       flush_cache_all();
+       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, #0x40\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");
+}
+
+static inline void zynq_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, #0x40\n"
+       "       mcr     p15, 0, %0, c1, c0, 1\n"
+         : "=&r" (v)
+         : "Ir" (CR_C)
+         : "cc");
+}
+
+static inline void zynq_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 (;;) {
+               dsb();
+               wfi();
+
+               /*
+                * 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 zynq_platform_cpu_die(unsigned int cpu)
+{
+       int spurious = 0;
+
+       /*
+        * we're ready for shutdown now, so do it
+        */
+       zynq_cpu_enter_lowpower();
+       zynq_platform_do_lowpower(cpu, &spurious);
+
+       /*
+        * bring this CPU back into the world of cache
+        * coherency, and then restore interrupts
+        */
+       zynq_cpu_leave_lowpower();
+
+       if (spurious)
+               pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious);
+}

diff --git a/arch/arm/mach-zynq/platsmp.c b/arch/arm/mach-zynq/platsmp.c
index cdfd888ca783ffa0085df9411e13766603075397..3072cbd7ec6f305f95a31b350fb13c7d534a20a2 100644 (file)
--- a/arch/arm/mach-zynq/platsmp.c
+++ b/arch/arm/mach-zynq/platsmp.c
@@ -146,4 +146,7 @@ struct smp_operations zynq_smp_ops __initdata = {
        .smp_prepare_cpus       = zynq_smp_prepare_cpus,
        .smp_secondary_init     = zynq_secondary_init,
        .smp_boot_secondary     = zynq_boot_secondary,
+#ifdef CONFIG_HOTPLUG_CPU
+       .cpu_die                = zynq_platform_cpu_die,
+#endif
 };