Highlights:

-----------
 - Following pen_release and boot_lock cleanup initiated by
   Russell King, .smp_prepare_cpus and .smp_boot_secondary STi callbacks
   must be reworked to keep secondary CPU's bringup.
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Merge tag 'sti-soc-for-v4.21-round1' of git://git.kernel.org/pub/scm/linux/kernel/git/pchotard/sti into next/late

Highlights:
-----------
- Following pen_release and boot_lock cleanup initiated by
  Russell King, .smp_prepare_cpus and .smp_boot_secondary STi callbacks
  must be reworked to keep secondary CPU's bringup.

* tag 'sti-soc-for-v4.21-round1' of git://git.kernel.org/pub/scm/linux/kernel/git/pchotard/sti:
  ARM: sti: remove pen_release and boot_lock

Signed-off-by: Olof Johansson <olof@lixom.net>
This commit is contained in:
Olof Johansson 2018-12-31 13:12:02 -08:00
commit 2081076ac7
3 changed files with 15 additions and 118 deletions

View File

@ -1,2 +1,2 @@
obj-$(CONFIG_SMP) += platsmp.o headsmp.o
obj-$(CONFIG_SMP) += platsmp.o
obj-$(CONFIG_ARCH_STI) += board-dt.o

View File

@ -1,43 +0,0 @@
/*
* arch/arm/mach-sti/headsmp.S
*
* Copyright (C) 2013 STMicroelectronics (R&D) Limited.
* http://www.st.com
*
* Cloned from linux/arch/arm/mach-vexpress/headsmp.S
*
* Copyright (c) 2003 ARM Limited
* 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/linkage.h>
#include <linux/init.h>
/*
* ST specific entry point for secondary CPUs. This provides
* a "holding pen" into which all secondary cores are held until we're
* ready for them to initialise.
*/
ENTRY(sti_secondary_startup)
mrc p15, 0, r0, c0, c0, 5
and r0, r0, #15
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
*/
b secondary_startup
ENDPROC(sti_secondary_startup)
1: .long .
.long pen_release

View File

@ -28,82 +28,33 @@
#include "smp.h"
static void write_pen_release(int val)
{
pen_release = val;
smp_wmb();
sync_cache_w(&pen_release);
}
static DEFINE_SPINLOCK(boot_lock);
static void sti_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);
/*
* Synchronise with the boot thread.
*/
spin_lock(&boot_lock);
spin_unlock(&boot_lock);
}
static u32 __iomem *cpu_strt_ptr;
static int sti_boot_secondary(unsigned int cpu, struct task_struct *idle)
{
unsigned long timeout;
unsigned long entry_pa = __pa_symbol(secondary_startup);
/*
* set synchronisation state between this boot processor
* and the secondary one
* Secondary CPU is initialised and started by a U-BOOTROM firmware.
* Secondary CPU is spinning and waiting for a write at cpu_strt_ptr.
* Writing secondary_startup address at cpu_strt_ptr makes it to
* jump directly to secondary_startup().
*/
spin_lock(&boot_lock);
__raw_writel(entry_pa, cpu_strt_ptr);
/*
* 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.
*
* Note that "pen_release" is the hardware CPU ID, whereas
* "cpu" is Linux's internal ID.
*/
write_pen_release(cpu_logical_map(cpu));
/* wmb so that data is actually written before cache flush is done */
smp_wmb();
sync_cache_w(cpu_strt_ptr);
/*
* Send the secondary CPU a soft interrupt, thereby causing
* it to jump to the secondary entrypoint.
*/
arch_send_wakeup_ipi_mask(cpumask_of(cpu));
timeout = jiffies + (1 * HZ);
while (time_before(jiffies, timeout)) {
smp_rmb();
if (pen_release == -1)
break;
udelay(10);
}
/*
* now the secondary core is starting up let it run its
* calibrations, then wait for it to finish
*/
spin_unlock(&boot_lock);
return pen_release != -1 ? -ENOSYS : 0;
return 0;
}
static void __init sti_smp_prepare_cpus(unsigned int max_cpus)
{
struct device_node *np;
void __iomem *scu_base;
u32 __iomem *cpu_strt_ptr;
u32 release_phys;
int cpu;
unsigned long entry_pa = __pa_symbol(sti_secondary_startup);
np = of_find_compatible_node(NULL, NULL, "arm,cortex-a9-scu");
@ -131,8 +82,8 @@ static void __init sti_smp_prepare_cpus(unsigned int max_cpus)
}
/*
* holding pen is usually configured in SBC DMEM but can also be
* in RAM.
* cpu-release-addr is usually configured in SBC DMEM but can
* also be in RAM.
*/
if (!memblock_is_memory(release_phys))
@ -142,22 +93,11 @@ static void __init sti_smp_prepare_cpus(unsigned int max_cpus)
cpu_strt_ptr =
(u32 __iomem *)phys_to_virt(release_phys);
__raw_writel(entry_pa, cpu_strt_ptr);
/*
* wmb so that data is actually written
* before cache flush is done
*/
smp_wmb();
sync_cache_w(cpu_strt_ptr);
if (!memblock_is_memory(release_phys))
iounmap(cpu_strt_ptr);
set_cpu_possible(cpu, true);
}
}
const struct smp_operations sti_smp_ops __initconst = {
.smp_prepare_cpus = sti_smp_prepare_cpus,
.smp_secondary_init = sti_secondary_init,
.smp_boot_secondary = sti_boot_secondary,
};