From 7d35b8d09fb0cb0a89c8c265a5bfb52c2867b1d5 Mon Sep 17 00:00:00 2001 From: Santosh Shilimkar Date: Mon, 2 Aug 2010 13:18:19 +0300 Subject: [PATCH] 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 Signed-off-by: Santosh Shilimkar Cc: Kevin Hilman Signed-off-by: Tony Lindgren --- arch/arm/mach-omap2/Makefile | 1 + .../mach-omap2/include/mach/omap4-common.h | 7 ++ arch/arm/mach-omap2/omap-hotplug.c | 79 +++++++++++++++++++ arch/arm/mach-omap2/omap-smp.c | 3 +- 4 files changed, 89 insertions(+), 1 deletion(-) create mode 100644 arch/arm/mach-omap2/omap-hotplug.c 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 + * + * 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 +#include +#include +#include + +#include +#include + +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 -- 2.20.1