MIPS: Allow L2 prefetch to be configured via debugfs (d478b088) · Commits · 戴 / test

arch/mips/Kconfig.debug

+10 −0

Original line number	Diff line number	Diff line
		@@ -149,4 +149,14 @@ endchoice

		endif # CPU_MIPSR6

		config SCACHE_DEBUGFS
		bool "L2 cache debugfs entries"
		depends on DEBUG_FS
		help
		Enable this to allow parts of the L2 cache configuration, such as
		whether or not prefetching is enabled, to be exposed to userland
		via debugfs.

		If unsure, say N.

		endmenu

arch/mips/mm/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -28,3 +28,4 @@ obj-$(CONFIG_IP22_CPU_SCACHE) += sc-ip22.o
		obj-$(CONFIG_R5000_CPU_SCACHE) += sc-r5k.o
		obj-$(CONFIG_RM7000_CPU_SCACHE) += sc-rm7k.o
		obj-$(CONFIG_MIPS_CPU_SCACHE) += sc-mips.o
		obj-$(CONFIG_SCACHE_DEBUGFS) += sc-debugfs.o

arch/mips/mm/sc-debugfs.c

0 → 100644

+81 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2015 Imagination Technologies
		* Author: Paul Burton <paul.burton@imgtec.com>
		*
		* This program is free software; you can redistribute it and/or modify it
		* under the terms of the GNU General Public License as published by the
		* Free Software Foundation; either version 2 of the License, or (at your
		* option) any later version.
		*/

		#include <asm/bcache.h>
		#include <asm/debug.h>
		#include <asm/uaccess.h>
		#include <linux/debugfs.h>
		#include <linux/init.h>

		static ssize_t sc_prefetch_read(struct file file, char __user user_buf,
		size_t count, loff_t *ppos)
		{
		bool enabled = bc_prefetch_is_enabled();
		char buf[3];

		buf[0] = enabled ? 'Y' : 'N';
		buf[1] = '\n';
		buf[2] = 0;

		return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
		}

		static ssize_t sc_prefetch_write(struct file *file,
		const char __user *user_buf,
		size_t count, loff_t *ppos)
		{
		char buf[32];
		ssize_t buf_size;
		bool enabled;
		int err;

		buf_size = min(count, sizeof(buf) - 1);
		if (copy_from_user(buf, user_buf, buf_size))
		return -EFAULT;

		buf[buf_size] = '\0';
		err = strtobool(buf, &enabled);
		if (err)
		return err;

		if (enabled)
		bc_prefetch_enable();
		else
		bc_prefetch_disable();

		return count;
		}

		static const struct file_operations sc_prefetch_fops = {
		.open = simple_open,
		.llseek = default_llseek,
		.read = sc_prefetch_read,
		.write = sc_prefetch_write,
		};

		static int __init sc_debugfs_init(void)
		{
		struct dentry dir, file;

		if (!mips_debugfs_dir)
		return -ENODEV;

		dir = debugfs_create_dir("l2cache", mips_debugfs_dir);
		if (IS_ERR(dir))
		return PTR_ERR(dir);

		file = debugfs_create_file("prefetch", S_IRUGO \| S_IWUSR, dir,
		NULL, &sc_prefetch_fops);
		if (IS_ERR(file))
		return PTR_ERR(file);

		return 0;
		}
		late_initcall(sc_debugfs_init);

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