ARM: oxnas: remove CPU hotplug implementation

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@armlinux.org.uk>

diff --git a/arch/arm/mach-oxnas/Makefile b/arch/arm/mach-oxnas/Makefile
index b625906..61a34e1 100644 (file)
--- 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 (file)
index 854f29b..0000000
--- 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 442cc8a..735141c 100644 (file)
--- 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 @@ unmap_scu:
 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);