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authorSantosh Shilimkar <santosh.shilimkar@ti.com>2010-08-02 12:18:19 +0200
committerTony Lindgren <tony@atomide.com>2010-08-02 12:18:19 +0200
commit7d35b8d09fb0cb0a89c8c265a5bfb52c2867b1d5 (patch)
tree1086c9e507b3565563bede1498487e30b7c3c1b3 /arch/arm/mach-omap2
parentomap4: Add smc API to read AuxCoreBoot0 register (diff)
downloadlinux-7d35b8d09fb0cb0a89c8c265a5bfb52c2867b1d5.tar.xz
linux-7d35b8d09fb0cb0a89c8c265a5bfb52c2867b1d5.zip
omap4: hotplug: Add basic CPU hotplug support
This patch adds cpu hotplug support for OMAP4430. Only CPU inactive state is supported as a low power state in the basic hot-plug support Signed-off-by: Rajendra Nayak <rnayak@ti.com> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Cc: Kevin Hilman <khilman@deeprootsystems.com> Signed-off-by: Tony Lindgren <tony@atomide.com>
Diffstat (limited to 'arch/arm/mach-omap2')
-rw-r--r--arch/arm/mach-omap2/Makefile1
-rw-r--r--arch/arm/mach-omap2/include/mach/omap4-common.h7
-rw-r--r--arch/arm/mach-omap2/omap-hotplug.c79
-rw-r--r--arch/arm/mach-omap2/omap-smp.c3
4 files changed, 89 insertions, 1 deletions
diff --git a/arch/arm/mach-omap2/Makefile b/arch/arm/mach-omap2/Makefile
index 3cb1b510ee42..0db90ff52617 100644
--- a/arch/arm/mach-omap2/Makefile
+++ b/arch/arm/mach-omap2/Makefile
@@ -22,6 +22,7 @@ obj-$(CONFIG_OMAP_MCBSP) += mcbsp.o
# SMP support ONLY available for OMAP4
obj-$(CONFIG_SMP) += omap-smp.o omap-headsmp.o
obj-$(CONFIG_LOCAL_TIMERS) += timer-mpu.o
+obj-$(CONFIG_HOTPLUG_CPU) += omap-hotplug.o
obj-$(CONFIG_ARCH_OMAP4) += omap44xx-smc.o omap4-common.o
AFLAGS_omap44xx-smc.o :=-Wa,-march=armv7-a
diff --git a/arch/arm/mach-omap2/include/mach/omap4-common.h b/arch/arm/mach-omap2/include/mach/omap4-common.h
index 423af3a6dd31..2744dfee1ff4 100644
--- a/arch/arm/mach-omap2/include/mach/omap4-common.h
+++ b/arch/arm/mach-omap2/include/mach/omap4-common.h
@@ -13,6 +13,13 @@
#ifndef OMAP_ARCH_OMAP4_COMMON_H
#define OMAP_ARCH_OMAP4_COMMON_H
+/*
+ * wfi used in low power code. Directly opcode is used instead
+ * of instruction to avoid mulit-omap build break
+ */
+#define do_wfi() \
+ __asm__ __volatile__ (".word 0xe320f003" : : : "memory")
+
#ifdef CONFIG_CACHE_L2X0
extern void __iomem *l2cache_base;
#endif
diff --git a/arch/arm/mach-omap2/omap-hotplug.c b/arch/arm/mach-omap2/omap-hotplug.c
new file mode 100644
index 000000000000..6cee456ca542
--- /dev/null
+++ b/arch/arm/mach-omap2/omap-hotplug.c
@@ -0,0 +1,79 @@
+/*
+ * OMAP4 SMP cpu-hotplug support
+ *
+ * Copyright (C) 2010 Texas Instruments, Inc.
+ * Author:
+ * Santosh Shilimkar <santosh.shilimkar@ti.com>
+ *
+ * Platform file needed for the OMAP4 SMP. This file is based on arm
+ * realview smp platform.
+ * Copyright (c) 2002 ARM Limited.
+ *
+ * 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 <linux/completion.h>
+
+#include <asm/cacheflush.h>
+#include <mach/omap4-common.h>
+
+static DECLARE_COMPLETION(cpu_killed);
+
+int platform_cpu_kill(unsigned int cpu)
+{
+ return wait_for_completion_timeout(&cpu_killed, 5000);
+}
+
+/*
+ * platform-specific code to shutdown a CPU
+ * Called with IRQs disabled
+ */
+void platform_cpu_die(unsigned int cpu)
+{
+ unsigned int this_cpu = hard_smp_processor_id();
+
+ if (cpu != this_cpu) {
+ pr_crit("platform_cpu_die running on %u, should be %u\n",
+ this_cpu, cpu);
+ BUG();
+ }
+ pr_notice("CPU%u: shutdown\n", cpu);
+ complete(&cpu_killed);
+ flush_cache_all();
+ dsb();
+
+ /*
+ * we're ready for shutdown now, so do it
+ */
+ if (omap_modify_auxcoreboot0(0x0, 0x200) != 0x0)
+ printk(KERN_CRIT "Secure clear status failed\n");
+
+ for (;;) {
+ /*
+ * Execute WFI
+ */
+ do_wfi();
+
+ if (omap_read_auxcoreboot0() == cpu) {
+ /*
+ * OK, proper wakeup, we're done
+ */
+ break;
+ }
+ pr_debug("CPU%u: spurious wakeup call\n", cpu);
+ }
+}
+
+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-omap2/omap-smp.c b/arch/arm/mach-omap2/omap-smp.c
index 1cf52313759e..af3c20c8d3f9 100644
--- a/arch/arm/mach-omap2/omap-smp.c
+++ b/arch/arm/mach-omap2/omap-smp.c
@@ -73,9 +73,10 @@ int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
* the AuxCoreBoot1 register is updated with cpu state
* A barrier is added to ensure that write buffer is drained
*/
- omap_modify_auxcoreboot0(0x200, 0x0);
+ omap_modify_auxcoreboot0(0x200, 0xfffffdff);
flush_cache_all();
smp_wmb();
+ smp_cross_call(cpumask_of(cpu));
/*
* Now the secondary core is starting up let it run its