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cache-debugfs.c

/*
 * debugfs ops for the L1 cache
 *
 *  Copyright (C) 2006  Paul Mundt
 *
 * 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/module.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <asm/processor.h>
#include <asm/uaccess.h>
#include <asm/cache.h>
#include <asm/io.h>

enum cache_type {
      CACHE_TYPE_ICACHE,
      CACHE_TYPE_DCACHE,
      CACHE_TYPE_UNIFIED,
};

static int cache_seq_show(struct seq_file *file, void *iter)
{
      unsigned int cache_type = (unsigned int)file->private;
      struct cache_info *cache;
      unsigned int waysize, way, cache_size;
      unsigned long ccr, base;
      static unsigned long addrstart = 0;

      /*
       * Go uncached immediately so we don't skew the results any
       * more than we already are..
       */
      jump_to_P2();

      ccr = ctrl_inl(CCR);
      if ((ccr & CCR_CACHE_ENABLE) == 0) {
            back_to_P1();

            seq_printf(file, "disabled\n");
            return 0;
      }

      if (cache_type == CACHE_TYPE_DCACHE) {
            base = CACHE_OC_ADDRESS_ARRAY;
            cache = &current_cpu_data.dcache;
      } else {
            base = CACHE_IC_ADDRESS_ARRAY;
            cache = &current_cpu_data.icache;
      }

      /*
       * Due to the amount of data written out (depending on the cache size),
       * we may be iterated over multiple times. In this case, keep track of
       * the entry position in addrstart, and rewind it when we've hit the
       * end of the cache.
       *
       * Likewise, the same code is used for multiple caches, so care must
       * be taken for bouncing addrstart back and forth so the appropriate
       * cache is hit.
       */
      cache_size = cache->ways * cache->sets * cache->linesz;
      if (((addrstart & 0xff000000) != base) ||
           (addrstart & 0x00ffffff) > cache_size)
            addrstart = base;

      waysize = cache->sets;

      /*
       * If the OC is already in RAM mode, we only have
       * half of the entries to consider..
       */
      if ((ccr & CCR_CACHE_ORA) && cache_type == CACHE_TYPE_DCACHE)
            waysize >>= 1;

      waysize <<= cache->entry_shift;

      for (way = 0; way < cache->ways; way++) {
            unsigned long addr;
            unsigned int line;

            seq_printf(file, "-----------------------------------------\n");
            seq_printf(file, "Way %d\n", way);
            seq_printf(file, "-----------------------------------------\n");

            for (addr = addrstart, line = 0;
                 addr < addrstart + waysize;
                 addr += cache->linesz, line++) {
                  unsigned long data = ctrl_inl(addr);

                  /* Check the V bit, ignore invalid cachelines */
                  if ((data & 1) == 0)
                        continue;

                  /* U: Dirty, cache tag is 10 bits up */
                  seq_printf(file, "%3d: %c 0x%lx\n",
                           line, data & 2 ? 'U' : ' ',
                           data & 0x1ffffc00);
            }

            addrstart += cache->way_incr;
      }

      back_to_P1();

      return 0;
}

static int cache_debugfs_open(struct inode *inode, struct file *file)
{
      return single_open(file, cache_seq_show, inode->i_private);
}

static const struct file_operations cache_debugfs_fops = {
      .owner            = THIS_MODULE,
      .open       = cache_debugfs_open,
      .read       = seq_read,
      .llseek           = seq_lseek,
      .release    = seq_release,
};

static int __init cache_debugfs_init(void)
{
      struct dentry *dcache_dentry, *icache_dentry;

      dcache_dentry = debugfs_create_file("dcache", S_IRUSR, NULL,
                                  (unsigned int *)CACHE_TYPE_DCACHE,
                                  &cache_debugfs_fops);
      if (IS_ERR(dcache_dentry))
            return PTR_ERR(dcache_dentry);

      icache_dentry = debugfs_create_file("icache", S_IRUSR, NULL,
                                  (unsigned int *)CACHE_TYPE_ICACHE,
                                  &cache_debugfs_fops);
      if (IS_ERR(icache_dentry)) {
            debugfs_remove(dcache_dentry);
            return PTR_ERR(icache_dentry);
      }

      return 0;
}
module_init(cache_debugfs_init);

MODULE_LICENSE("GPL v2");

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