/*
 * 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 <linux/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
 */
#if defined(CONFIG_SUPERH32) && !defined(CONFIG_CPU_J2)
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();
        }
}