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/*
* arch/sh/kernel/cpu/init.c
*
* CPU init code
*
* Copyright (C) 2002, 2003 Paul Mundt
* Copyright (C) 2003 Richard Curnow
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <asm/processor.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/cacheflush.h>
#include <asm/cache.h>
#include <asm/io.h>
extern void detect_cpu_and_cache_system(void);
/*
* Generic wrapper for command line arguments to disable on-chip
* peripherals (nofpu, nodsp, and so forth).
*/
#define onchip_setup(x) \
static int x##_disabled __initdata = 0; \
\
static int __init x##_setup(char *opts) \
{ \
x##_disabled = 1; \
return 1; \
} \
__setup("no" __stringify(x), x##_setup);
onchip_setup(fpu);
onchip_setup(dsp);
/*
* Generic first-level cache init
*/
static void __init cache_init(void)
{
unsigned long ccr, flags;
if (cpu_data->type == CPU_SH_NONE)
panic("Unknown CPU");
jump_to_P2();
ccr = ctrl_inl(CCR);
/*
* At this point we don't know whether the cache is enabled or not - a
* bootloader may have enabled it. There are at least 2 things that
* could be dirty in the cache at this point:
* 1. kernel command line set up by boot loader
* 2. spilled registers from the prolog of this function
* => before re-initialising the cache, we must do a purge of the whole
* cache out to memory for safety. As long as nothing is spilled
* during the loop to lines that have already been done, this is safe.
* - RPC
*/
if (ccr & CCR_CACHE_ENABLE) {
unsigned long ways, waysize, addrstart;
waysize = cpu_data->dcache.sets;
/*
* If the OC is already in RAM mode, we only have
* half of the entries to flush..
*/
if (ccr & CCR_CACHE_ORA)
waysize >>= 1;
waysize <<= cpu_data->dcache.entry_shift;
#ifdef CCR_CACHE_EMODE
/* If EMODE is not set, we only have 1 way to flush. */
if (!(ccr & CCR_CACHE_EMODE))
ways = 1;
else
#endif
ways = cpu_data->dcache.ways;
addrstart = CACHE_OC_ADDRESS_ARRAY;
do {
unsigned long addr;
for (addr = addrstart;
addr < addrstart + waysize;
addr += cpu_data->dcache.linesz)
ctrl_outl(0, addr);
addrstart += cpu_data->dcache.way_incr;
} while (--ways);
}
/*
* Default CCR values .. enable the caches
* and invalidate them immediately..
*/
flags = CCR_CACHE_ENABLE | CCR_CACHE_INVALIDATE;
#ifdef CCR_CACHE_EMODE
/* Force EMODE if possible */
if (cpu_data->dcache.ways > 1)
flags |= CCR_CACHE_EMODE;
else
flags &= ~CCR_CACHE_EMODE;
#endif
#ifdef CONFIG_SH_WRITETHROUGH
/* Turn on Write-through caching */
flags |= CCR_CACHE_WT;
#else
/* .. or default to Write-back */
flags |= CCR_CACHE_CB;
#endif
#ifdef CONFIG_SH_OCRAM
/* Turn on OCRAM -- halve the OC */
flags |= CCR_CACHE_ORA;
cpu_data->dcache.sets >>= 1;
cpu_data->dcache.way_size = cpu_data->dcache.sets *
cpu_data->dcache.linesz;
#endif
ctrl_outl(flags, CCR);
back_to_P1();
}
#ifdef CONFIG_SH_DSP
static void __init release_dsp(void)
{
unsigned long sr;
/* Clear SR.DSP bit */
__asm__ __volatile__ (
"stc\tsr, %0\n\t"
"and\t%1, %0\n\t"
"ldc\t%0, sr\n\t"
: "=&r" (sr)
: "r" (~SR_DSP)
);
}
static void __init dsp_init(void)
{
unsigned long sr;
/*
* Set the SR.DSP bit, wait for one instruction, and then read
* back the SR value.
*/
__asm__ __volatile__ (
"stc\tsr, %0\n\t"
"or\t%1, %0\n\t"
"ldc\t%0, sr\n\t"
"nop\n\t"
"stc\tsr, %0\n\t"
: "=&r" (sr)
: "r" (SR_DSP)
);
/* If the DSP bit is still set, this CPU has a DSP */
if (sr & SR_DSP)
cpu_data->flags |= CPU_HAS_DSP;
/* Now that we've determined the DSP status, clear the DSP bit. */
release_dsp();
}
#endif /* CONFIG_SH_DSP */
/**
* sh_cpu_init
*
* This is our initial entry point for each CPU, and is invoked on the boot
* CPU prior to calling start_kernel(). For SMP, a combination of this and
* start_secondary() will bring up each processor to a ready state prior
* to hand forking the idle loop.
*
* We do all of the basic processor init here, including setting up the
* caches, FPU, DSP, kicking the UBC, etc. By the time start_kernel() is
* hit (and subsequently platform_setup()) things like determining the
* CPU subtype and initial configuration will all be done.
*
* Each processor family is still responsible for doing its own probing
* and cache configuration in detect_cpu_and_cache_system().
*/
asmlinkage void __init sh_cpu_init(void)
{
/* First, probe the CPU */
detect_cpu_and_cache_system();
/* Init the cache */
cache_init();
/* Disable the FPU */
if (fpu_disabled) {
printk("FPU Disabled\n");
cpu_data->flags &= ~CPU_HAS_FPU;
disable_fpu();
}
/* FPU initialization */
if ((cpu_data->flags & CPU_HAS_FPU)) {
clear_thread_flag(TIF_USEDFPU);
clear_used_math();
}
#ifdef CONFIG_SH_DSP
/* Probe for DSP */
dsp_init();
/* Disable the DSP */
if (dsp_disabled) {
printk("DSP Disabled\n");
cpu_data->flags &= ~CPU_HAS_DSP;
release_dsp();
}
#endif
#ifdef CONFIG_UBC_WAKEUP
/*
* Some brain-damaged loaders decided it would be a good idea to put
* the UBC to sleep. This causes some issues when it comes to things
* like PTRACE_SINGLESTEP or doing hardware watchpoints in GDB. So ..
* we wake it up and hope that all is well.
*/
ubc_wakeup();
#endif
}
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