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sc-r5k.c

/*
 * Copyright (C) 1997, 2001 Ralf Baechle (ralf@gnu.org),
 * derived from r4xx0.c by David S. Miller (dm@engr.sgi.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>

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

#define SC_LINE 32
#define SC_PAGE (128*SC_LINE)

static inline void blast_r5000_scache(void)
{
      unsigned long start = INDEX_BASE;
      unsigned long end = start + scache_size;

      while(start < end) {
            cache_op(R5K_Page_Invalidate_S, start);
            start += SC_PAGE;
      }
}

static void r5k_dma_cache_inv_sc(unsigned long addr, unsigned long size)
{
      unsigned long end, a;

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

      if (size >= scache_size) {
            blast_r5000_scache();
            return;
      }

      /* On the R5000 secondary cache we cannot
       * invalidate less than a page at a time.
       * The secondary cache is physically indexed, write-through.
       */
      a = addr & ~(SC_PAGE - 1);
      end = (addr + size - 1) & ~(SC_PAGE - 1);
      while (a <= end) {
            cache_op(R5K_Page_Invalidate_S, a);
            a += SC_PAGE;
      }
}

static void r5k_sc_enable(void)
{
        unsigned long flags;

      local_irq_save(flags);
      set_c0_config(R5K_CONF_SE);
      blast_r5000_scache();
      local_irq_restore(flags);
}

static void r5k_sc_disable(void)
{
        unsigned long flags;

      local_irq_save(flags);
      blast_r5000_scache();
      clear_c0_config(R5K_CONF_SE);
      local_irq_restore(flags);
}

static inline int __init r5k_sc_probe(void)
{
      unsigned long config = read_c0_config();

      if (config & CONF_SC)
            return(0);

      scache_size = (512 * 1024) << ((config & R5K_CONF_SS) >> 20);

      printk("R5000 SCACHE size %ldkB, linesize 32 bytes.\n",
                  scache_size >> 10);

      return 1;
}

static struct bcache_ops r5k_sc_ops = {
      .bc_enable = r5k_sc_enable,
      .bc_disable = r5k_sc_disable,
      .bc_wback_inv = r5k_dma_cache_inv_sc,
      .bc_inv = r5k_dma_cache_inv_sc
};

void __cpuinit r5k_sc_init(void)
{
      if (r5k_sc_probe()) {
            r5k_sc_enable();
            bcops = &r5k_sc_ops;
      }
}

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