sc-mips.c
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/*
* Copyright (C) 2006 Chris Dearman (chris@mips.com),
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <asm/mipsregs.h>
#include <asm/bcache.h>
#include <asm/cacheops.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/mmu_context.h>
#include <asm/r4kcache.h>
/*
* MIPS32/MIPS64 L2 cache handling
*/
/*
* Writeback and invalidate the secondary cache before DMA.
*/
static void mips_sc_wback_inv(unsigned long addr, unsigned long size)
{
blast_scache_range(addr, addr + size);
}
/*
* Invalidate the secondary cache before DMA.
*/
static void mips_sc_inv(unsigned long addr, unsigned long size)
{
unsigned long lsize = cpu_scache_line_size();
unsigned long almask = ~(lsize - 1);
cache_op(Hit_Writeback_Inv_SD, addr & almask);
cache_op(Hit_Writeback_Inv_SD, (addr + size - 1) & almask);
blast_inv_scache_range(addr, addr + size);
}
static void mips_sc_enable(void)
{
/* L2 cache is permanently enabled */
}
static void mips_sc_disable(void)
{
/* L2 cache is permanently enabled */
}
static struct bcache_ops mips_sc_ops = {
.bc_enable = mips_sc_enable,
.bc_disable = mips_sc_disable,
.bc_wback_inv = mips_sc_wback_inv,
.bc_inv = mips_sc_inv
};
/*
* Check if the L2 cache controller is activated on a particular platform.
* MTI's L2 controller and the L2 cache controller of Broadcom's BMIPS
* cores both use c0_config2's bit 12 as "L2 Bypass" bit, that is the
* cache being disabled. However there is no guarantee for this to be
* true on all platforms. In an act of stupidity the spec defined bits
* 12..15 as implementation defined so below function will eventually have
* to be replaced by a platform specific probe.
*/
static inline int mips_sc_is_activated(struct cpuinfo_mips *c)
{
unsigned int config2 = read_c0_config2();
unsigned int tmp;
/* Check the bypass bit (L2B) */
switch (c->cputype) {
case CPU_34K:
case CPU_74K:
case CPU_1004K:
case CPU_BMIPS5000:
if (config2 & (1 << 12))
return 0;
}
tmp = (config2 >> 4) & 0x0f;
if (0 < tmp && tmp <= 7)
c->scache.linesz = 2 << tmp;
else
return 0;
return 1;
}
static inline int __init mips_sc_probe(void)
{
struct cpuinfo_mips *c = ¤t_cpu_data;
unsigned int config1, config2;
unsigned int tmp;
/* Mark as not present until probe completed */
c->scache.flags |= MIPS_CACHE_NOT_PRESENT;
/* Ignore anything but MIPSxx processors */
if (c->isa_level != MIPS_CPU_ISA_M32R1 &&
c->isa_level != MIPS_CPU_ISA_M32R2 &&
c->isa_level != MIPS_CPU_ISA_M64R1 &&
c->isa_level != MIPS_CPU_ISA_M64R2)
return 0;
/* Does this MIPS32/MIPS64 CPU have a config2 register? */
config1 = read_c0_config1();
if (!(config1 & MIPS_CONF_M))
return 0;
config2 = read_c0_config2();
if (!mips_sc_is_activated(c))
return 0;
tmp = (config2 >> 8) & 0x0f;
if (0 <= tmp && tmp <= 7)
c->scache.sets = 64 << tmp;
else
return 0;
tmp = (config2 >> 0) & 0x0f;
if (0 <= tmp && tmp <= 7)
c->scache.ways = tmp + 1;
else
return 0;
c->scache.waysize = c->scache.sets * c->scache.linesz;
c->scache.waybit = __ffs(c->scache.waysize);
c->scache.flags &= ~MIPS_CACHE_NOT_PRESENT;
return 1;
}
int __cpuinit mips_sc_init(void)
{
int found = mips_sc_probe();
if (found) {
mips_sc_enable();
bcops = &mips_sc_ops;
}
return found;
}