From 453689e407f2b7c0a72a2e6fb2ef84c20475773b Mon Sep 17 00:00:00 2001 From: Joseph Lo Date: Thu, 16 Aug 2012 17:31:52 +0800 Subject: [PATCH] ARM: tegra20: add CPU hotplug support Hotplug function put CPU in offline or online mode at runtime. When the CPU been put into offline, it was been clock gated. The offline CPU can be power gated, when the remaining CPU goes into LP2. Based on the worked by: Colin Cross Gary King Signed-off-by: Joseph Lo Signed-off-by: Stephen Warren --- arch/arm/mach-tegra/Makefile | 1 + arch/arm/mach-tegra/common.c | 1 + arch/arm/mach-tegra/hotplug.c | 8 ++++ arch/arm/mach-tegra/sleep-t20.S | 82 +++++++++++++++++++++++++++++++++ arch/arm/mach-tegra/sleep.h | 4 ++ 5 files changed, 96 insertions(+) create mode 100644 arch/arm/mach-tegra/sleep-t20.S diff --git a/arch/arm/mach-tegra/Makefile b/arch/arm/mach-tegra/Makefile index efb2f90a8f77..84d21f514418 100644 --- a/arch/arm/mach-tegra/Makefile +++ b/arch/arm/mach-tegra/Makefile @@ -15,6 +15,7 @@ obj-$(CONFIG_CPU_IDLE) += sleep.o obj-$(CONFIG_ARCH_TEGRA_2x_SOC) += tegra20_clocks.o obj-$(CONFIG_ARCH_TEGRA_2x_SOC) += tegra20_clocks_data.o obj-$(CONFIG_ARCH_TEGRA_2x_SOC) += tegra2_emc.o +obj-$(CONFIG_ARCH_TEGRA_2x_SOC) += sleep-t20.o obj-$(CONFIG_ARCH_TEGRA_3x_SOC) += tegra30_clocks.o obj-$(CONFIG_ARCH_TEGRA_3x_SOC) += tegra30_clocks_data.o obj-$(CONFIG_ARCH_TEGRA_3x_SOC) += sleep-t30.o diff --git a/arch/arm/mach-tegra/common.c b/arch/arm/mach-tegra/common.c index 06520564d815..0560538bf598 100644 --- a/arch/arm/mach-tegra/common.c +++ b/arch/arm/mach-tegra/common.c @@ -136,6 +136,7 @@ void __init tegra20_init_early(void) tegra_init_cache(0x331, 0x441); tegra_pmc_init(); tegra_powergate_init(); + tegra20_hotplug_init(); } #endif #ifdef CONFIG_ARCH_TEGRA_3x_SOC diff --git a/arch/arm/mach-tegra/hotplug.c b/arch/arm/mach-tegra/hotplug.c index be92d4c07606..d02a35476135 100644 --- a/arch/arm/mach-tegra/hotplug.c +++ b/arch/arm/mach-tegra/hotplug.c @@ -56,6 +56,14 @@ int platform_cpu_disable(unsigned int cpu) return cpu == 0 ? -EPERM : 0; } +#ifdef CONFIG_ARCH_TEGRA_2x_SOC +extern void tegra20_hotplug_shutdown(void); +void __init tegra20_hotplug_init(void) +{ + tegra_hotplug_shutdown = tegra20_hotplug_shutdown; +} +#endif + #ifdef CONFIG_ARCH_TEGRA_3x_SOC extern void tegra30_hotplug_shutdown(void); void __init tegra30_hotplug_init(void) diff --git a/arch/arm/mach-tegra/sleep-t20.S b/arch/arm/mach-tegra/sleep-t20.S new file mode 100644 index 000000000000..a36ae413e2b8 --- /dev/null +++ b/arch/arm/mach-tegra/sleep-t20.S @@ -0,0 +1,82 @@ +/* + * Copyright (c) 2010-2012, NVIDIA Corporation. All rights reserved. + * Copyright (c) 2011, Google, Inc. + * + * Author: Colin Cross + * Gary King + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ + +#include + +#include + +#include + +#include "sleep.h" +#include "flowctrl.h" + +#if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_PM_SLEEP) +/* + * tegra20_hotplug_shutdown(void) + * + * puts the current cpu in reset + * should never return + */ +ENTRY(tegra20_hotplug_shutdown) + /* Turn off SMP coherency */ + exit_smp r4, r5 + + /* Put this CPU down */ + cpu_id r0 + bl tegra20_cpu_shutdown + mov pc, lr @ should never get here +ENDPROC(tegra20_hotplug_shutdown) + +/* + * tegra20_cpu_shutdown(int cpu) + * + * r0 is cpu to reset + * + * puts the specified CPU in wait-for-event mode on the flow controller + * and puts the CPU in reset + * can be called on the current cpu or another cpu + * if called on the current cpu, does not return + * MUST NOT BE CALLED FOR CPU 0. + * + * corrupts r0-r3, r12 + */ +ENTRY(tegra20_cpu_shutdown) + cmp r0, #0 + moveq pc, lr @ must not be called for CPU 0 + + cpu_to_halt_reg r1, r0 + ldr r3, =TEGRA_FLOW_CTRL_VIRT + mov r2, #FLOW_CTRL_WAITEVENT | FLOW_CTRL_JTAG_RESUME + str r2, [r3, r1] @ put flow controller in wait event mode + ldr r2, [r3, r1] + isb + dsb + movw r1, 0x1011 + mov r1, r1, lsl r0 + ldr r3, =TEGRA_CLK_RESET_VIRT + str r1, [r3, #0x340] @ put slave CPU in reset + isb + dsb + cpu_id r3 + cmp r3, r0 + beq . + mov pc, lr +ENDPROC(tegra20_cpu_shutdown) +#endif diff --git a/arch/arm/mach-tegra/sleep.h b/arch/arm/mach-tegra/sleep.h index 0f047eb3ca2e..e25a7cd703d9 100644 --- a/arch/arm/mach-tegra/sleep.h +++ b/arch/arm/mach-tegra/sleep.h @@ -23,6 +23,8 @@ + IO_CPU_VIRT) #define TEGRA_FLOW_CTRL_VIRT (TEGRA_FLOW_CTRL_BASE - IO_PPSB_PHYS \ + IO_PPSB_VIRT) +#define TEGRA_CLK_RESET_VIRT (TEGRA_CLK_RESET_BASE - IO_PPSB_PHYS \ + + IO_PPSB_VIRT) #ifdef __ASSEMBLY__ /* returns the offset of the flow controller halt register for a cpu */ @@ -72,8 +74,10 @@ #else #ifdef CONFIG_HOTPLUG_CPU +void tegra20_hotplug_init(void); void tegra30_hotplug_init(void); #else +static inline void tegra20_hotplug_init(void) {} static inline void tegra30_hotplug_init(void) {} #endif -- 2.39.5