linux/arch/arm/mach-imx/platsmp.c
Shawn Guo dc13ba2950 ARM: imx: do not bring up unavailable cores
The i.MX6 Quad can be fused as i.MX6 Dual chip, and similarly i.MX6
DualLite can be fused as i.MX6 Solo.  The actual number of available
cores can be found out from SCU.

Since we do not reflect the fusing thing in device tree, the function
arm_dt_init_cpu_maps() will always call set_cpu_possible(true) for 4
cores on i.MX6 Quad/Dual and 2 cores for i.MX6 DualLite/Solo.  This
causes failures when kernel tries to bring those unavailable cores
online.  For example, the following failure message will be seen when
booting an i.MX6 Solo chip.

  CPU1: failed to come online

Though kernel will still boot fine, the message is somehow annoying.
Let's get rid of it by calling set_cpu_possible(false) on those
unavailable cores.

While at it, the set_cpu_possible(true) for available cores is removed,
since it's already been done in arm_dt_init_cpu_maps().

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
2013-04-12 19:28:15 +08:00

106 lines
2.3 KiB
C

/*
* Copyright 2011 Freescale Semiconductor, Inc.
* Copyright 2011 Linaro Ltd.
*
* The code contained herein is licensed under the GNU General Public
* License. You may obtain a copy of the GNU General Public License
* Version 2 or later at the following locations:
*
* http://www.opensource.org/licenses/gpl-license.html
* http://www.gnu.org/copyleft/gpl.html
*/
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/irqchip/arm-gic.h>
#include <asm/page.h>
#include <asm/smp_scu.h>
#include <asm/mach/map.h>
#include "common.h"
#include "hardware.h"
#define SCU_STANDBY_ENABLE (1 << 5)
static void __iomem *scu_base;
static struct map_desc scu_io_desc __initdata = {
/* .virtual and .pfn are run-time assigned */
.length = SZ_4K,
.type = MT_DEVICE,
};
void __init imx_scu_map_io(void)
{
unsigned long base;
/* Get SCU base */
asm("mrc p15, 4, %0, c15, c0, 0" : "=r" (base));
scu_io_desc.virtual = IMX_IO_P2V(base);
scu_io_desc.pfn = __phys_to_pfn(base);
iotable_init(&scu_io_desc, 1);
scu_base = IMX_IO_ADDRESS(base);
}
void imx_scu_standby_enable(void)
{
u32 val = readl_relaxed(scu_base);
val |= SCU_STANDBY_ENABLE;
writel_relaxed(val, scu_base);
}
static void __cpuinit imx_secondary_init(unsigned int cpu)
{
/*
* if any interrupts are already enabled for the primary
* core (e.g. timer irq), then they will not have been enabled
* for us: do so
*/
gic_secondary_init(0);
}
static int __cpuinit imx_boot_secondary(unsigned int cpu, struct task_struct *idle)
{
imx_set_cpu_jump(cpu, v7_secondary_startup);
imx_enable_cpu(cpu, true);
return 0;
}
/*
* Initialise the CPU possible map early - this describes the CPUs
* which may be present or become present in the system.
*/
static void __init imx_smp_init_cpus(void)
{
int i, ncores;
ncores = scu_get_core_count(scu_base);
for (i = ncores; i < NR_CPUS; i++)
set_cpu_possible(i, false);
}
void imx_smp_prepare(void)
{
scu_enable(scu_base);
}
static void __init imx_smp_prepare_cpus(unsigned int max_cpus)
{
imx_smp_prepare();
}
struct smp_operations imx_smp_ops __initdata = {
.smp_init_cpus = imx_smp_init_cpus,
.smp_prepare_cpus = imx_smp_prepare_cpus,
.smp_secondary_init = imx_secondary_init,
.smp_boot_secondary = imx_boot_secondary,
#ifdef CONFIG_HOTPLUG_CPU
.cpu_die = imx_cpu_die,
.cpu_kill = imx_cpu_kill,
#endif
};