sc-ip22.c

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/*
 * sc-ip22.c: Indy cache management functions.
 *
 * Copyright (C) 1997, 2001 Ralf Baechle ([email protected]),
 * derived from r4xx0.c by David S. Miller ([email protected]).
 */
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>

#include <asm/bcache.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/bootinfo.h>
#include <asm/sgi/ip22.h>
#include <asm/sgi/mc.h>

/* Secondary cache size in bytes, if present.  */
static unsigned long scache_size;

#undef DEBUG_CACHE

#define SC_SIZE 0x00080000
#define SC_LINE 32
#define CI_MASK (SC_SIZE - SC_LINE)
#define SC_INDEX(n) ((n) & CI_MASK)

static inline void indy_sc_wipe(unsigned long first, unsigned long last)
{
    unsigned long tmp;

    __asm__ __volatile__(
    ".set\tpush\t\t\t# indy_sc_wipe\n\t"
    ".set\tnoreorder\n\t"
    ".set\tmips3\n\t"
    ".set\tnoat\n\t"
    "mfc0\t%2, $12\n\t"
    "li\t$1, 0x80\t\t\t# Go 64 bit\n\t"
    "mtc0\t$1, $12\n\t"

    "dli\t$1, 0x9000000080000000\n\t"
    "or\t%0, $1\t\t\t# first line to flush\n\t"
    "or\t%1, $1\t\t\t# last line to flush\n\t"
    ".set\tat\n\t"

    "1:\tsw\t$0, 0(%0)\n\t"
    "bne\t%0, %1, 1b\n\t"
    " daddu\t%0, 32\n\t"

    "mtc0\t%2, $12\t\t\t# Back to 32 bit\n\t"
    "nop; nop; nop; nop;\n\t"
    ".set\tpop"
    : "=r" (first), "=r" (last), "=&r" (tmp)
    : "0" (first), "1" (last));
}

static void indy_sc_wback_invalidate(unsigned long addr, unsigned long size)
{
    unsigned long first_line, last_line;
    unsigned long flags;

#ifdef DEBUG_CACHE
    printk("indy_sc_wback_invalidate[%08lx,%08lx]", addr, size);
#endif

    /* Catch bad driver code */
    BUG_ON(size == 0);

    /* Which lines to flush?  */
    first_line = SC_INDEX(addr);
    last_line = SC_INDEX(addr + size - 1);

    local_irq_save(flags);
    if (first_line <= last_line) {
        indy_sc_wipe(first_line, last_line);
        goto out;
    }

    indy_sc_wipe(first_line, SC_SIZE - SC_LINE);
    indy_sc_wipe(0, last_line);
out:
    local_irq_restore(flags);
}

static void indy_sc_enable(void)
{
    unsigned long addr, tmp1, tmp2;

    /* This is really cool... */
#ifdef DEBUG_CACHE
    printk("Enabling R4600 SCACHE\n");
#endif
    __asm__ __volatile__(
    ".set\tpush\n\t"
    ".set\tnoreorder\n\t"
    ".set\tmips3\n\t"
    "mfc0\t%2, $12\n\t"
    "nop; nop; nop; nop;\n\t"
    "li\t%1, 0x80\n\t"
    "mtc0\t%1, $12\n\t"
    "nop; nop; nop; nop;\n\t"
    "li\t%0, 0x1\n\t"
    "dsll\t%0, 31\n\t"
    "lui\t%1, 0x9000\n\t"
    "dsll32\t%1, 0\n\t"
    "or\t%0, %1, %0\n\t"
    "sb\t$0, 0(%0)\n\t"
    "mtc0\t$0, $12\n\t"
    "nop; nop; nop; nop;\n\t"
    "mtc0\t%2, $12\n\t"
    "nop; nop; nop; nop;\n\t"
    ".set\tpop"
    : "=r" (tmp1), "=r" (tmp2), "=r" (addr));
}

static void indy_sc_disable(void)
{
    unsigned long tmp1, tmp2, tmp3;

#ifdef DEBUG_CACHE
    printk("Disabling R4600 SCACHE\n");
#endif
    __asm__ __volatile__(
    ".set\tpush\n\t"
    ".set\tnoreorder\n\t"
    ".set\tmips3\n\t"
    "li\t%0, 0x1\n\t"
    "dsll\t%0, 31\n\t"
    "lui\t%1, 0x9000\n\t"
    "dsll32\t%1, 0\n\t"
    "or\t%0, %1, %0\n\t"
    "mfc0\t%2, $12\n\t"
    "nop; nop; nop; nop\n\t"
    "li\t%1, 0x80\n\t"
    "mtc0\t%1, $12\n\t"
    "nop; nop; nop; nop\n\t"
    "sh\t$0, 0(%0)\n\t"
    "mtc0\t$0, $12\n\t"
    "nop; nop; nop; nop\n\t"
    "mtc0\t%2, $12\n\t"
    "nop; nop; nop; nop\n\t"
    ".set\tpop"
    : "=r" (tmp1), "=r" (tmp2), "=r" (tmp3));
}

static inline int __init indy_sc_probe(void)
{
    unsigned int size = ip22_eeprom_read(&sgimc->eeprom, 17);
    if (size == 0)
        return 0;

    size <<= PAGE_SHIFT;
    printk(KERN_INFO "R4600/R5000 SCACHE size %dK, linesize 32 bytes.\n",
           size >> 10);
    scache_size = size;

    return 1;
}

/* XXX Check with wje if the Indy caches can differenciate between
   writeback + invalidate and just invalidate.  */
static struct bcache_ops indy_sc_ops = {
    .bc_enable = indy_sc_enable,
    .bc_disable = indy_sc_disable,
    .bc_wback_inv = indy_sc_wback_invalidate,
    .bc_inv = indy_sc_wback_invalidate
};

void __cpuinit indy_sc_init(void)
{
    if (indy_sc_probe()) {
        indy_sc_enable();
        bcops = &indy_sc_ops;
    }
}