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/*
* Copyright (C) 2013 Imagination Technologies
* Author: Paul Burton <paul.burton@mips.com>
*
* 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
* option) any later version.
*/
#include <linux/errno.h>
#include <linux/percpu.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/spinlock.h>
#include <asm/mips-cps.h>
void __iomem *mips_cpc_base;
static DEFINE_PER_CPU_ALIGNED(spinlock_t, cpc_core_lock);
static DEFINE_PER_CPU_ALIGNED(unsigned long, cpc_core_lock_flags);
phys_addr_t __weak mips_cpc_default_phys_base(void)
{
struct device_node *cpc_node;
struct resource res;
int err;
cpc_node = of_find_compatible_node(of_root, NULL, "mti,mips-cpc");
if (cpc_node) {
err = of_address_to_resource(cpc_node, 0, &res);
if (!err)
return res.start;
}
return 0;
}
/**
* mips_cpc_phys_base - retrieve the physical base address of the CPC
*
* This function returns the physical base address of the Cluster Power
* Controller memory mapped registers, or 0 if no Cluster Power Controller
* is present.
*/
static phys_addr_t mips_cpc_phys_base(void)
{
unsigned long cpc_base;
if (!mips_cm_present())
return 0;
if (!(read_gcr_cpc_status() & CM_GCR_CPC_STATUS_EX))
return 0;
/* If the CPC is already enabled, leave it so */
cpc_base = read_gcr_cpc_base();
if (cpc_base & CM_GCR_CPC_BASE_CPCEN)
return cpc_base & CM_GCR_CPC_BASE_CPCBASE;
/* Otherwise, use the default address */
cpc_base = mips_cpc_default_phys_base();
if (!cpc_base)
return cpc_base;
/* Enable the CPC, mapped at the default address */
write_gcr_cpc_base(cpc_base | CM_GCR_CPC_BASE_CPCEN);
return cpc_base;
}
int mips_cpc_probe(void)
{
phys_addr_t addr;
unsigned int cpu;
for_each_possible_cpu(cpu)
spin_lock_init(&per_cpu(cpc_core_lock, cpu));
addr = mips_cpc_phys_base();
if (!addr)
return -ENODEV;
mips_cpc_base = ioremap_nocache(addr, 0x8000);
if (!mips_cpc_base)
return -ENXIO;
return 0;
}
void mips_cpc_lock_other(unsigned int core)
{
unsigned int curr_core;
if (mips_cm_revision() >= CM_REV_CM3)
/* Systems with CM >= 3 lock the CPC via mips_cm_lock_other */
return;
preempt_disable();
curr_core = cpu_core(¤t_cpu_data);
spin_lock_irqsave(&per_cpu(cpc_core_lock, curr_core),
per_cpu(cpc_core_lock_flags, curr_core));
write_cpc_cl_other(core << __ffs(CPC_Cx_OTHER_CORENUM));
/*
* Ensure the core-other region reflects the appropriate core &
* VP before any accesses to it occur.
*/
mb();
}
void mips_cpc_unlock_other(void)
{
unsigned int curr_core;
if (mips_cm_revision() >= CM_REV_CM3)
/* Systems with CM >= 3 lock the CPC via mips_cm_lock_other */
return;
curr_core = cpu_core(¤t_cpu_data);
spin_unlock_irqrestore(&per_cpu(cpc_core_lock, curr_core),
per_cpu(cpc_core_lock_flags, curr_core));
preempt_enable();
}
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