The CPU hotplug implementation on this platform is cargo-culted from
the plat-versatile implementation, and is buggy. Once a CPU hits the
"low power" loop, it will wait for pen_release to be set to the CPU
number to wake up again - but nothing in this implementation does that.
So, once a CPU has entered cpu_die() it will never, ever leave.
Remove this useless cargo-culted implementation.
Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxx>
---
arch/arm/mach-oxnas/Makefile | 1 -
arch/arm/mach-oxnas/hotplug.c | 109 ------------------------------------------
arch/arm/mach-oxnas/platsmp.c | 4 --
3 files changed, 114 deletions(-)
delete mode 100644 arch/arm/mach-oxnas/hotplug.c
diff --git a/arch/arm/mach-oxnas/Makefile b/arch/arm/mach-oxnas/Makefile
index b625906a9970..61a34e1c0f22 100644
--- a/arch/arm/mach-oxnas/Makefile
+++ b/arch/arm/mach-oxnas/Makefile
@@ -1,2 +1 @@
obj-$(CONFIG_SMP) += platsmp.o headsmp.o
-obj-$(CONFIG_HOTPLUG_CPU) += hotplug.o
diff --git a/arch/arm/mach-oxnas/hotplug.c b/arch/arm/mach-oxnas/hotplug.c
deleted file mode 100644
index 854f29b8cba6..000000000000
--- a/arch/arm/mach-oxnas/hotplug.c
+++ /dev/null
@@ -1,109 +0,0 @@
-/*
- * 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/cp15.h>
-#include <asm/smp_plat.h>
-
-static inline void cpu_enter_lowpower(void)
-{
- unsigned int v;
-
- asm volatile(
- " mcr p15, 0, %1, c7, c5, 0\n"
- " mcr p15, 0, %1, c7, c10, 4\n"
- /*
- * Turn off coherency
- */
- " mrc p15, 0, %0, c1, c0, 1\n"
- " bic %0, %0, #0x20\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 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, #0x20\n"
- " mcr p15, 0, %0, c1, c0, 1\n"
- : "=&r" (v)
- : "Ir" (CR_C)
- : "cc");
-}
-
-static inline void 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 (;;) {
- /*
- * here's the WFI
- */
- asm(".word 0xe320f003\n"
- :
- :
- : "memory", "cc");
-
- if (pen_release == cpu_logical_map(cpu)) {
- /*
- * OK, proper wakeup, we're done
- */
- break;
- }
-
- /*
- * 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 ox820_cpu_die(unsigned int cpu)
-{
- int spurious = 0;
-
- /*
- * we're ready for shutdown now, so do it
- */
- cpu_enter_lowpower();
- platform_do_lowpower(cpu, &spurious);
-
- /*
- * bring this CPU back into the world of cache
- * coherency, and then restore interrupts
- */
- cpu_leave_lowpower();
-
- if (spurious)
- pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious);
-}
diff --git a/arch/arm/mach-oxnas/platsmp.c b/arch/arm/mach-oxnas/platsmp.c
index 442cc8a2f7dc..735141c0e3a3 100644
--- a/arch/arm/mach-oxnas/platsmp.c
+++ b/arch/arm/mach-oxnas/platsmp.c
@@ -19,7 +19,6 @@
#include <asm/smp_scu.h>
extern void ox820_secondary_startup(void);
-extern void ox820_cpu_die(unsigned int cpu);
static void __iomem *cpu_ctrl;
static void __iomem *gic_cpu_ctrl;
@@ -94,9 +93,6 @@ static void __init ox820_smp_prepare_cpus(unsigned int max_cpus)
static const struct smp_operations ox820_smp_ops __initconst = {
.smp_prepare_cpus = ox820_smp_prepare_cpus,
.smp_boot_secondary = ox820_boot_secondary,
-#ifdef CONFIG_HOTPLUG_CPU
- .cpu_die = ox820_cpu_die,
-#endif
};
CPU_METHOD_OF_DECLARE(ox820_smp, "oxsemi,ox820-smp", &ox820_smp_ops);
--
2.7.4
