[PATCH v3 11/12] arm: zynq: Add hotplug support
Michal Simek
michal.simek at xilinx.com
Thu Mar 28 12:38:11 EDT 2013
Signed-off-by: Michal Simek <michal.simek at xilinx.com>
---
v3: Use zynq_ prefix for all functions
v2: Change platform_cpu_die name function to zynq_platform_cpu_dio
Fix header
Add cpu compilation flags to be able to build on V6 too
---
arch/arm/mach-zynq/Makefile | 3 ++
arch/arm/mach-zynq/common.h | 3 ++
arch/arm/mach-zynq/hotplug.c | 104 ++++++++++++++++++++++++++++++++++++++++++
arch/arm/mach-zynq/platsmp.c | 3 ++
4 files changed, 113 insertions(+)
create mode 100644 arch/arm/mach-zynq/hotplug.c
diff --git a/arch/arm/mach-zynq/Makefile b/arch/arm/mach-zynq/Makefile
index b595d22..1b25d92 100644
--- 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 fd308f8..fbbd0e2 100644
--- 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
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 cdfd888..3072cbd 100644
--- 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
};
--
1.7.9.7
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