Rich Felker 57155c6523 sh: disable aliased page logic on NOMMU models
SH3/4 (with MMU) have a virtually indexed cache, requiring explicit
work to avoid consistency problems arising from having the same
physical address range cached in multiple cache lines. This is
unneeded for the NOMMU case, and some of the resulting code paths
(kmap_coherent) don't work. SH2 only avoided this problem by having a
4-way associative cache with way size equal to the page size (4k),
yielding no cache index bits outside of the page offset and thus no
aliases.

Signed-off-by: Rich Felker <dalias@libc.org>
2016-07-31 03:33:32 +00:00

370 lines
8.4 KiB
C

/*
* arch/sh/kernel/cpu/init.c
*
* CPU init code
*
* Copyright (C) 2002 - 2009 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 <linux/mm.h>
#include <linux/log2.h>
#include <asm/mmu_context.h>
#include <asm/processor.h>
#include <asm/uaccess.h>
#include <asm/page.h>
#include <asm/cacheflush.h>
#include <asm/cache.h>
#include <asm/elf.h>
#include <asm/io.h>
#include <asm/smp.h>
#include <asm/sh_bios.h>
#include <asm/setup.h>
#ifdef CONFIG_SH_FPU
#define cpu_has_fpu 1
#else
#define cpu_has_fpu 0
#endif
#ifdef CONFIG_SH_DSP
#define cpu_has_dsp 1
#else
#define cpu_has_dsp 0
#endif
/*
* Generic wrapper for command line arguments to disable on-chip
* peripherals (nofpu, nodsp, and so forth).
*/
#define onchip_setup(x) \
static int x##_disabled = !cpu_has_##x; \
\
static int x##_setup(char *opts) \
{ \
x##_disabled = 1; \
return 1; \
} \
__setup("no" __stringify(x), x##_setup);
onchip_setup(fpu);
onchip_setup(dsp);
#ifdef CONFIG_SPECULATIVE_EXECUTION
#define CPUOPM 0xff2f0000
#define CPUOPM_RABD (1 << 5)
static void speculative_execution_init(void)
{
/* Clear RABD */
__raw_writel(__raw_readl(CPUOPM) & ~CPUOPM_RABD, CPUOPM);
/* Flush the update */
(void)__raw_readl(CPUOPM);
ctrl_barrier();
}
#else
#define speculative_execution_init() do { } while (0)
#endif
#ifdef CONFIG_CPU_SH4A
#define EXPMASK 0xff2f0004
#define EXPMASK_RTEDS (1 << 0)
#define EXPMASK_BRDSSLP (1 << 1)
#define EXPMASK_MMCAW (1 << 4)
static void expmask_init(void)
{
unsigned long expmask = __raw_readl(EXPMASK);
/*
* Future proofing.
*
* Disable support for slottable sleep instruction, non-nop
* instructions in the rte delay slot, and associative writes to
* the memory-mapped cache array.
*/
expmask &= ~(EXPMASK_RTEDS | EXPMASK_BRDSSLP | EXPMASK_MMCAW);
__raw_writel(expmask, EXPMASK);
ctrl_barrier();
}
#else
#define expmask_init() do { } while (0)
#endif
/* 2nd-level cache init */
void __attribute__ ((weak)) l2_cache_init(void)
{
}
/*
* Generic first-level cache init
*/
#ifdef CONFIG_SUPERH32
static void cache_init(void)
{
unsigned long ccr, flags;
jump_to_uncached();
ccr = __raw_readl(SH_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 = current_cpu_data.dcache.sets;
#ifdef CCR_CACHE_ORA
/*
* If the OC is already in RAM mode, we only have
* half of the entries to flush..
*/
if (ccr & CCR_CACHE_ORA)
waysize >>= 1;
#endif
waysize <<= current_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 = current_cpu_data.dcache.ways;
addrstart = CACHE_OC_ADDRESS_ARRAY;
do {
unsigned long addr;
for (addr = addrstart;
addr < addrstart + waysize;
addr += current_cpu_data.dcache.linesz)
__raw_writel(0, addr);
addrstart += current_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 (current_cpu_data.dcache.ways > 1)
flags |= CCR_CACHE_EMODE;
else
flags &= ~CCR_CACHE_EMODE;
#endif
#if defined(CONFIG_CACHE_WRITETHROUGH)
/* Write-through */
flags |= CCR_CACHE_WT;
#elif defined(CONFIG_CACHE_WRITEBACK)
/* Write-back */
flags |= CCR_CACHE_CB;
#else
/* Off */
flags &= ~CCR_CACHE_ENABLE;
#endif
l2_cache_init();
__raw_writel(flags, SH_CCR);
back_to_cached();
}
#else
#define cache_init() do { } while (0)
#endif
#define CSHAPE(totalsize, linesize, assoc) \
((totalsize & ~0xff) | (linesize << 4) | assoc)
#define CACHE_DESC_SHAPE(desc) \
CSHAPE((desc).way_size * (desc).ways, ilog2((desc).linesz), (desc).ways)
static void detect_cache_shape(void)
{
l1d_cache_shape = CACHE_DESC_SHAPE(current_cpu_data.dcache);
if (current_cpu_data.dcache.flags & SH_CACHE_COMBINED)
l1i_cache_shape = l1d_cache_shape;
else
l1i_cache_shape = CACHE_DESC_SHAPE(current_cpu_data.icache);
if (current_cpu_data.flags & CPU_HAS_L2_CACHE)
l2_cache_shape = CACHE_DESC_SHAPE(current_cpu_data.scache);
else
l2_cache_shape = -1; /* No S-cache */
}
static void fpu_init(void)
{
/* Disable the FPU */
if (fpu_disabled && (current_cpu_data.flags & CPU_HAS_FPU)) {
printk("FPU Disabled\n");
current_cpu_data.flags &= ~CPU_HAS_FPU;
}
disable_fpu();
clear_used_math();
}
#ifdef CONFIG_SH_DSP
static void 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 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)
current_cpu_data.flags |= CPU_HAS_DSP;
/* Disable the DSP */
if (dsp_disabled && (current_cpu_data.flags & CPU_HAS_DSP)) {
printk("DSP Disabled\n");
current_cpu_data.flags &= ~CPU_HAS_DSP;
}
/* Now that we've determined the DSP status, clear the DSP bit. */
release_dsp();
}
#else
static inline void dsp_init(void) { }
#endif /* CONFIG_SH_DSP */
/**
* 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, 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 cpu_probe().
*/
asmlinkage void cpu_init(void)
{
current_thread_info()->cpu = hard_smp_processor_id();
/* First, probe the CPU */
cpu_probe();
if (current_cpu_data.type == CPU_SH_NONE)
panic("Unknown CPU");
/* First setup the rest of the I-cache info */
current_cpu_data.icache.entry_mask = current_cpu_data.icache.way_incr -
current_cpu_data.icache.linesz;
current_cpu_data.icache.way_size = current_cpu_data.icache.sets *
current_cpu_data.icache.linesz;
/* And the D-cache too */
current_cpu_data.dcache.entry_mask = current_cpu_data.dcache.way_incr -
current_cpu_data.dcache.linesz;
current_cpu_data.dcache.way_size = current_cpu_data.dcache.sets *
current_cpu_data.dcache.linesz;
/* Init the cache */
cache_init();
if (raw_smp_processor_id() == 0) {
#ifdef CONFIG_MMU
shm_align_mask = max_t(unsigned long,
current_cpu_data.dcache.way_size - 1,
PAGE_SIZE - 1);
#else
shm_align_mask = PAGE_SIZE - 1;
#endif
/* Boot CPU sets the cache shape */
detect_cache_shape();
}
fpu_init();
dsp_init();
/*
* Initialize the per-CPU ASID cache very early, since the
* TLB flushing routines depend on this being setup.
*/
current_cpu_data.asid_cache = NO_CONTEXT;
current_cpu_data.phys_bits = __in_29bit_mode() ? 29 : 32;
speculative_execution_init();
expmask_init();
/* Do the rest of the boot processor setup */
if (raw_smp_processor_id() == 0) {
/* Save off the BIOS VBR, if there is one */
sh_bios_vbr_init();
/*
* Setup VBR for boot CPU. Secondary CPUs do this through
* start_secondary().
*/
per_cpu_trap_init();
/*
* Boot processor to setup the FP and extended state
* context info.
*/
init_thread_xstate();
}
}