ARM: owl: smp: Drop bogus holding pen

The S500 SoC can start secondary CPUs without busy-looping for pen_release,
so simplify the SMP code compared to the LeMaker kernel tree.

Fixes: 172067e0bc87 ("ARM: owl: Implement CPU enable-method for S500")
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Cc: David Liu <liuwei@actions-semi.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

diff --git a/arch/arm/mach-actions/headsmp.S b/arch/arm/mach-actions/headsmp.S
index dc4832f..65f53bd 100644 (file)
--- a/arch/arm/mach-actions/headsmp.S
+++ b/arch/arm/mach-actions/headsmp.S
@@ -2,6 +2,8 @@
  * Copyright 2012 Actions Semi Inc.
  * Author: Actions Semi, Inc.
  *
+ * Copyright (c) 2017 Andreas Färber
+ *
  * This program is free software; you can redistribute  it and/or modify it
  * under  the terms of  the GNU General  Public License as published by the
  * Free Software Foundation;  either version 2 of the  License, or (at your
@@ -46,23 +48,5 @@ ENTRY(owl_v7_invalidate_l1)
 ENDPROC(owl_v7_invalidate_l1)
 
 ENTRY(owl_secondary_startup)
-       mrc     p15, 0, r0, c0, c0, 5
-       and     r0, r0, #0xf
-       adr     r4, 1f
-       ldmia   r4, {r5, r6}
-       sub     r4, r4, r5
-       add     r6, r6, r4
-pen:
-       ldr     r7, [r6]
-       cmp     r7, r0
-       bne     pen
-
-       /*
-        * we've been released from the holding pen: secondary_stack
-        * should now contain the SVC stack for this core
-        */
        bl      owl_v7_invalidate_l1
        b       secondary_startup
-
-1:     .long   .
-       .long   pen_release

diff --git a/arch/arm/mach-actions/platsmp.c b/arch/arm/mach-actions/platsmp.c
index b4806ce..12a9e33 100644 (file)
--- a/arch/arm/mach-actions/platsmp.c
+++ b/arch/arm/mach-actions/platsmp.c
@@ -41,26 +41,6 @@ static int ncores;
 
 static DEFINE_SPINLOCK(boot_lock);
 
-static void write_pen_release(int val)
-{
-       pen_release = val;
-       smp_wmb();
-       __cpuc_flush_dcache_area((void *)&pen_release, sizeof(pen_release));
-       outer_clean_range(__pa(&pen_release), __pa(&pen_release + 1));
-}
-
-static void s500_smp_secondary_init(unsigned int cpu)
-{
-       /*
-        * let the primary processor know we're out of the
-        * pen, then head off into the C entry point
-        */
-       write_pen_release(-1);
-
-       spin_lock(&boot_lock);
-       spin_unlock(&boot_lock);
-}
-
 void owl_secondary_startup(void);
 
 static int s500_wakeup_secondary(unsigned int cpu)
@@ -115,12 +95,6 @@ static int s500_smp_boot_secondary(unsigned int cpu, struct task_struct *idle)
 
        spin_lock(&boot_lock);
 
-       /*
-        * The secondary processor is waiting to be released from
-        * the holding pen - release it, then wait for it to flag
-        * that it has been released by resetting pen_release.
-        */
-       write_pen_release(cpu_logical_map(cpu));
        smp_send_reschedule(cpu);
 
        timeout = jiffies + (1 * HZ);
@@ -134,7 +108,7 @@ static int s500_smp_boot_secondary(unsigned int cpu, struct task_struct *idle)
 
        spin_unlock(&boot_lock);
 
-       return pen_release != -1 ? -ENOSYS : 0;
+       return 0;
 }
 
 static void __init s500_smp_prepare_cpus(unsigned int max_cpus)
@@ -192,7 +166,6 @@ static void __init s500_smp_prepare_cpus(unsigned int max_cpus)
 
 static const struct smp_operations s500_smp_ops __initconst = {
        .smp_prepare_cpus = s500_smp_prepare_cpus,
-       .smp_secondary_init = s500_smp_secondary_init,
        .smp_boot_secondary = s500_smp_boot_secondary,
 };
 CPU_METHOD_OF_DECLARE(s500_smp, "actions,s500-smp", &s500_smp_ops);