linux/arch/arm/mach-omap2/omap-hotplug.c
Tony Lindgren 351b7c4907 ARM: omap2+: Revert omap-smp.c changes resetting CPU1 during boot
Commit 3251885285 ("ARM: OMAP4+: Reset CPU1 properly for kexec") started
unconditionally resetting CPU1 because of a kexec boot issue I was seeing
earlier on omap4 when doing kexec boot between two different kernel
versions.

This caused issues on some systems. We should only reset CPU1 as a last
resort option, and try to avoid it where possible. Doing an unconditional
CPU1 reset causes issues for example when booting a bootloader configured
secure OS running on CPU1 as reported by Andrew F. Davis <afd@ti.com>.

We can't completely remove the reset of CPU1 as it would break kexec
booting from older kernels. But we can limit the CPU1 reset to cases
where CPU1 is wrongly parked within the memory area used by the booting
kernel. Then later on we can add support for parking CPU1 for kexec out
of the SDRAM back to bootrom.

So let's first fix the regression reported by Andrew by making CPU1 reset
conditional. To do this, we need to:

1. Save configured AUX_CORE_BOOT_1 for later

2. Modify AUX_CORE_BOOT_0 reading code to for HS SoCs to return
   the whole register instead of the CPU mask

3. Check if CPU1 is wrongly parked into the booting kernel by the
   previous kernel and reset if needed

Fixes: 3251885285 ("ARM: OMAP4+: Reset CPU1 properly for kexec")
Reported-by: Andrew F. Davis <afd@ti.com>
Cc: Andrew F. Davis <afd@ti.com>
Cc: Keerthy <j-keerthy@ti.com>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Santosh Shilimkar <ssantosh@kernel.org>
Cc: Tero Kristo <t-kristo@ti.com>
Tested-by: Keerthy <j-keerthy@ti.com>
Tested-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
2017-03-27 10:10:42 -07:00

73 lines
1.6 KiB
C

/*
* OMAP4 SMP cpu-hotplug support
*
* Copyright (C) 2010 Texas Instruments, Inc.
* Author:
* Santosh Shilimkar <santosh.shilimkar@ti.com>
*
* Platform file needed for the OMAP4 SMP. This file is based on arm
* realview smp platform.
* Copyright (c) 2002 ARM Limited.
*
* 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 <linux/io.h>
#include "omap-wakeupgen.h"
#include "common.h"
#include "powerdomain.h"
/*
* platform-specific code to shutdown a CPU
* Called with IRQs disabled
*/
void omap4_cpu_die(unsigned int cpu)
{
unsigned int boot_cpu = 0;
void __iomem *base = omap_get_wakeupgen_base();
/*
* we're ready for shutdown now, so do it
*/
if (omap_secure_apis_support()) {
if (omap_modify_auxcoreboot0(0x0, 0x200) != 0x0)
pr_err("Secure clear status failed\n");
} else {
writel_relaxed(0, base + OMAP_AUX_CORE_BOOT_0);
}
for (;;) {
/*
* Enter into low power state
*/
omap4_hotplug_cpu(cpu, PWRDM_POWER_OFF);
if (omap_secure_apis_support())
boot_cpu = omap_read_auxcoreboot0() >> 9;
else
boot_cpu =
readl_relaxed(base + OMAP_AUX_CORE_BOOT_0) >> 5;
if (boot_cpu == smp_processor_id()) {
/*
* OK, proper wakeup, we're done
*/
break;
}
pr_debug("CPU%u: spurious wakeup call\n", cpu);
}
}
/* Needed by kexec and platform_can_cpu_hotplug() */
int omap4_cpu_kill(unsigned int cpu)
{
return 1;
}