| Message ID | 20170227091338.9800-1-linus.walleij@linaro.org |
|---|---|
| State | Accepted |
| Commit | 3131d970f0d86bea41811766d55fc638e382daf3 |
| Headers | show |
On Mon, Feb 27, 2017 at 10:13:38AM +0100, Linus Walleij wrote: > The pen hold/release scheme was copied over to Ux500 from the ARM > reference designs like most of these at the time. It is not needed > at all, and was mostly removed in commit c00def71efd9 > "ARM: ux500: simplify secondary CPU boot". > > However on the suspend/resume path and hot plug/unplug of CPUs, > the .cpu_die() callback was still waiting for the pen to be > released which made it spin forever and the second core never come > back online after suspend/resume. > > Fix this by simply replacing the strange custom .cpu_die() with > a oneline wfi() just like e.g. the qcom platform does. This fixes > the issue and makes the second core come up properly after > suspend/resume. > > As a side effect, this rids us of the completely surplus local > setup.h and hotplug.c files, and we just compile this into platsmp.c > with everything else SMP. > > Cc: stable@vger.kernel.org > Fixes: c00def71efd9 ("ARM: ux500: simplify secondary CPU boot") > Cc: Ulf Hansson <ulf.hansson@linaro.org> > Signed-off-by: Linus Walleij <linus.walleij@linaro.org> > --- > ARM SoC folks: please apply this directly for fixes. The bug > has been around for a while, it is nice to have both CPUs > online after suspend/resume. Looks like this one was included in next/late merge by Arnd. -Olof
diff --git a/arch/arm/mach-ux500/Makefile b/arch/arm/mach-ux500/Makefile index c2499bff4986..a9a3453548f4 100644 --- a/arch/arm/mach-ux500/Makefile +++ b/arch/arm/mach-ux500/Makefile @@ -5,7 +5,4 @@ obj-y := pm.o obj-$(CONFIG_UX500_SOC_DB8500) += cpu-db8500.o obj-$(CONFIG_SMP) += platsmp.o -obj-$(CONFIG_HOTPLUG_CPU) += hotplug.o obj-$(CONFIG_PM_GENERIC_DOMAINS) += pm_domains.o - -CFLAGS_hotplug.o += -march=armv7-a diff --git a/arch/arm/mach-ux500/cpu-db8500.c b/arch/arm/mach-ux500/cpu-db8500.c index 24529cf58df6..28083ef72819 100644 --- a/arch/arm/mach-ux500/cpu-db8500.c +++ b/arch/arm/mach-ux500/cpu-db8500.c @@ -31,8 +31,6 @@ #include <asm/mach/map.h> #include <asm/mach/arch.h> -#include "setup.h" - #include "db8500-regs.h" static int __init ux500_l2x0_unlock(void) diff --git a/arch/arm/mach-ux500/hotplug.c b/arch/arm/mach-ux500/hotplug.c deleted file mode 100644 index 1cbed0331fd3..000000000000 --- a/arch/arm/mach-ux500/hotplug.c +++ /dev/null @@ -1,37 +0,0 @@ -/* - * Copyright (C) STMicroelectronics 2009 - * Copyright (C) ST-Ericsson SA 2010 - * - * License Terms: GNU General Public License v2 - * Based on ARM realview platform - * - * Author: Sundar Iyer <sundar.iyer@stericsson.com> - * - */ -#include <linux/kernel.h> -#include <linux/errno.h> -#include <linux/smp.h> - -#include <asm/smp_plat.h> - -#include "setup.h" - -/* - * platform-specific code to shutdown a CPU - * - * Called with IRQs disabled - */ -void ux500_cpu_die(unsigned int cpu) -{ - /* directly enter low power state, skipping secure registers */ - for (;;) { - __asm__ __volatile__("dsb\n\t" "wfi\n\t" - : : : "memory"); - if (pen_release == cpu_logical_map(cpu)) { - /* - * OK, proper wakeup, we're done - */ - break; - } - } -} diff --git a/arch/arm/mach-ux500/platsmp.c b/arch/arm/mach-ux500/platsmp.c index e0ee139fdebf..19c165aeecd2 100644 --- a/arch/arm/mach-ux500/platsmp.c +++ b/arch/arm/mach-ux500/platsmp.c @@ -23,8 +23,6 @@ #include <asm/smp_plat.h> #include <asm/smp_scu.h> -#include "setup.h" - #include "db8500-regs.h" /* Magic triggers in backup RAM */ @@ -90,6 +88,13 @@ static int ux500_boot_secondary(unsigned int cpu, struct task_struct *idle) return 0; } +#ifdef CONFIG_HOTPLUG_CPU +void ux500_cpu_die(unsigned int cpu) +{ + wfi(); +} +#endif + static const struct smp_operations ux500_smp_ops __initconst = { .smp_prepare_cpus = ux500_smp_prepare_cpus, .smp_boot_secondary = ux500_boot_secondary, diff --git a/arch/arm/mach-ux500/setup.h b/arch/arm/mach-ux500/setup.h deleted file mode 100644 index 988e7c77068d..000000000000 --- a/arch/arm/mach-ux500/setup.h +++ /dev/null @@ -1,16 +0,0 @@ -/* - * Copyright (C) 2009 ST-Ericsson. - * - * 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. - * - * These symbols are needed for board-specific files to call their - * own cpu-specific files - */ -#ifndef __ASM_ARCH_SETUP_H -#define __ASM_ARCH_SETUP_H - -extern void ux500_cpu_die(unsigned int cpu); - -#endif /* __ASM_ARCH_SETUP_H */
The pen hold/release scheme was copied over to Ux500 from the ARM reference designs like most of these at the time. It is not needed at all, and was mostly removed in commit c00def71efd9 "ARM: ux500: simplify secondary CPU boot". However on the suspend/resume path and hot plug/unplug of CPUs, the .cpu_die() callback was still waiting for the pen to be released which made it spin forever and the second core never come back online after suspend/resume. Fix this by simply replacing the strange custom .cpu_die() with a oneline wfi() just like e.g. the qcom platform does. This fixes the issue and makes the second core come up properly after suspend/resume. As a side effect, this rids us of the completely surplus local setup.h and hotplug.c files, and we just compile this into platsmp.c with everything else SMP. Cc: stable@vger.kernel.org Fixes: c00def71efd9 ("ARM: ux500: simplify secondary CPU boot") Cc: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> --- ARM SoC folks: please apply this directly for fixes. The bug has been around for a while, it is nice to have both CPUs online after suspend/resume. --- arch/arm/mach-ux500/Makefile | 3 --- arch/arm/mach-ux500/cpu-db8500.c | 2 -- arch/arm/mach-ux500/hotplug.c | 37 ------------------------------------- arch/arm/mach-ux500/platsmp.c | 9 +++++++-- arch/arm/mach-ux500/setup.h | 16 ---------------- 5 files changed, 7 insertions(+), 60 deletions(-) delete mode 100644 arch/arm/mach-ux500/hotplug.c delete mode 100644 arch/arm/mach-ux500/setup.h -- 2.9.3