Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 * xor.c : Multiple Devices driver for Linux

 *

 * Copyright (C) 1996, 1997, 1998, 1999, 2000,

 * Ingo Molnar, Matti Aarnio, Jakub Jelinek, Richard Henderson.

 *

 * Dispatch optimized RAID-5 checksumming functions.

 *

 * 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, or (at your option)

 * any later version.

 *

 * You should have received a copy of the GNU General Public License

 * (for example /usr/src/linux/COPYING); if not, write to the Free

 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

 */

#define BH_TRACE 0

#include <linux/module.h>

#include <linux/raid/md.h>

#include <linux/raid/xor.h>

#include <asm/xor.h>

/* The xor routines to use.  */

static struct xor_block_template *active_template;

void

xor_blocks(unsigned int src_count, unsigned int bytes, void *dest, void **srcs)

{

        unsigned long *p1, *p2, *p3, *p4;

        p1 = (unsigned long *) srcs[0];

        if (src_count == 1) {

                active_template->do_2(bytes, dest, p1);

                return;

        }

        p2 = (unsigned long *) srcs[1];

        if (src_count == 2) {

                active_template->do_3(bytes, dest, p1, p2);

                return;

        }

        p3 = (unsigned long *) srcs[2];

        if (src_count == 3) {

                active_template->do_4(bytes, dest, p1, p2, p3);

                return;

        }

        p4 = (unsigned long *) srcs[3];

        active_template->do_5(bytes, dest, p1, p2, p3, p4);

}

EXPORT_SYMBOL(xor_blocks);

/* Set of all registered templates.  */

static struct xor_block_template *template_list;

#define BENCH_SIZE (PAGE_SIZE)

static void

do_xor_speed(struct xor_block_template *tmpl, void *b1, void *b2)

{

        int speed;

        unsigned long now;

        int i, count, max;

        tmpl->next = template_list;

        template_list = tmpl;

        /*

         * Count the number of XORs done during a whole jiffy, and use

         * this to calculate the speed of checksumming.  We use a 2-page

         * allocation to have guaranteed color L1-cache layout.

         */

        max = 0;

        for (i = 0; i < 5; i++) {

                now = jiffies;

                count = 0;

                while (jiffies == now) {

                        mb(); /* prevent loop optimzation */

                        tmpl->do_2(BENCH_SIZE, b1, b2);

                        mb();

                        count++;

                        mb();

                }

                if (count > max)

                        max = count;

        }

        speed = max * (HZ * BENCH_SIZE / 1024);

        tmpl->speed = speed;

        printk(KERN_INFO "   %-10s: %5d.%03d MB/sec\n", tmpl->name,

               speed / 1000, speed % 1000);

}

static int __init

calibrate_xor_blocks(void)

{

        void *b1, *b2;

        struct xor_block_template *f, *fastest;

        b1 = (void *) __get_free_pages(GFP_KERNEL, 2);

        if (!b1) {

                printk(KERN_WARNING "xor: Yikes!  No memory available.\n");

                return -ENOMEM;

        }

        b2 = b1 + 2*PAGE_SIZE + BENCH_SIZE;

        /*

         * If this arch/cpu has a short-circuited selection, don't loop through

         * all the possible functions, just test the best one

         */

        fastest = NULL;

#ifdef XOR_SELECT_TEMPLATE

                fastest = XOR_SELECT_TEMPLATE(fastest);

#endif

#define xor_speed(templ)        do_xor_speed((templ), b1, b2)

        if (fastest) {

                printk(KERN_INFO "xor: automatically using best "

                        "checksumming function: %s\n",

                        fastest->name);

                xor_speed(fastest);

        } else {

                printk(KERN_INFO "xor: measuring software checksum speed\n");

                XOR_TRY_TEMPLATES;

                fastest = template_list;

                for (f = fastest; f; f = f->next)

                        if (f->speed > fastest->speed)

                                fastest = f;

        }

        printk(KERN_INFO "xor: using function: %s (%d.%03d MB/sec)\n",

               fastest->name, fastest->speed / 1000, fastest->speed % 1000);

#undef xor_speed

        free_pages((unsigned long)b1, 2);

        active_template = fastest;

        return 0;

}

static __exit void xor_exit(void) { }

MODULE_LICENSE("GPL");

/* when built-in xor.o must initialize before drivers/md/md.o */

core_initcall(calibrate_xor_blocks);

module_exit(xor_exit);