d478b088a2
When debugging or examining the performance of a system it can be useful to examine the effect of L2 prefetching. Provide an optional debugfs entry to allow a user to enable or disable L2 prefetching. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: Maciej W. Rozycki <macro@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/11182/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
81 lines
1.8 KiB
C
81 lines
1.8 KiB
C
/*
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* Copyright (C) 2015 Imagination Technologies
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* Author: Paul Burton <paul.burton@imgtec.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*/
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#include <asm/bcache.h>
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#include <asm/debug.h>
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#include <asm/uaccess.h>
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#include <linux/debugfs.h>
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#include <linux/init.h>
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static ssize_t sc_prefetch_read(struct file *file, char __user *user_buf,
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size_t count, loff_t *ppos)
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{
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bool enabled = bc_prefetch_is_enabled();
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char buf[3];
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buf[0] = enabled ? 'Y' : 'N';
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buf[1] = '\n';
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buf[2] = 0;
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return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
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}
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static ssize_t sc_prefetch_write(struct file *file,
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const char __user *user_buf,
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size_t count, loff_t *ppos)
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{
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char buf[32];
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ssize_t buf_size;
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bool enabled;
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int err;
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buf_size = min(count, sizeof(buf) - 1);
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if (copy_from_user(buf, user_buf, buf_size))
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return -EFAULT;
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buf[buf_size] = '\0';
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err = strtobool(buf, &enabled);
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if (err)
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return err;
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if (enabled)
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bc_prefetch_enable();
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else
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bc_prefetch_disable();
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return count;
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}
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static const struct file_operations sc_prefetch_fops = {
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.open = simple_open,
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.llseek = default_llseek,
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.read = sc_prefetch_read,
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.write = sc_prefetch_write,
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};
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static int __init sc_debugfs_init(void)
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{
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struct dentry *dir, *file;
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if (!mips_debugfs_dir)
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return -ENODEV;
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dir = debugfs_create_dir("l2cache", mips_debugfs_dir);
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if (IS_ERR(dir))
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return PTR_ERR(dir);
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file = debugfs_create_file("prefetch", S_IRUGO | S_IWUSR, dir,
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NULL, &sc_prefetch_fops);
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if (IS_ERR(file))
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return PTR_ERR(file);
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return 0;
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}
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late_initcall(sc_debugfs_init);
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