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/*
* linux/arch/arm/kernel/smp_scu.c
*
* 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/init.h>
#include <linux/io.h>
#include <asm/smp_scu.h>
#include <asm/cacheflush.h>
#define SCU_CTRL 0x00
#define SCU_CONFIG 0x04
#define SCU_CPU_STATUS 0x08
#define SCU_INVALIDATE 0x0c
#define SCU_FPGA_REVISION 0x10
/*
* Get the number of CPU cores from the SCU configuration
*/
unsigned int __init scu_get_core_count(void __iomem *scu_base)
{
unsigned int ncores = __raw_readl(scu_base + SCU_CONFIG);
return (ncores & 0x03) + 1;
}
/*
* Enable the SCU
*/
void __init scu_enable(void __iomem *scu_base)
{
u32 scu_ctrl;
scu_ctrl = __raw_readl(scu_base + SCU_CTRL);
/* already enabled? */
if (scu_ctrl & 1)
return;
scu_ctrl |= 1;
__raw_writel(scu_ctrl, scu_base + SCU_CTRL);
/*
* Ensure that the data accessed by CPU0 before the SCU was
* initialised is visible to the other CPUs.
*/
flush_cache_all();
}
/*
* Set the executing CPUs power mode as defined. This will be in
* preparation for it executing a WFI instruction.
*
* This function must be called with preemption disabled, and as it
* has the side effect of disabling coherency, caches must have been
* flushed. Interrupts must also have been disabled.
*/
int scu_power_mode(void __iomem *scu_base, unsigned int mode)
{
unsigned int val;
int cpu = smp_processor_id();
if (mode > 3 || mode == 1 || cpu > 3)
return -EINVAL;
val = __raw_readb(scu_base + SCU_CPU_STATUS + cpu) & ~0x03;
val |= mode;
__raw_writeb(val, scu_base + SCU_CPU_STATUS + cpu);
return 0;
}
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