cache.c

/*-
 * Copyright (c) 2014 The FreeBSD Foundation
 *
 * This software was developed by Semihalf under
 * the sponsorship of the FreeBSD Foundation.
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/param.h>

#include <machine/armreg.h>
#include <machine/atomic.h>

#include <stand.h>

#include "bootstrap.h"
#include "cache.h"

static long cache_flags;
#define	CACHE_FLAG_DIC_OFF	(1<<0)
#define	CACHE_FLAG_IDC_OFF	(1<<1)

static bool
get_cache_dic(uint64_t ctr)
{
	if ((cache_flags & CACHE_FLAG_DIC_OFF) != 0) {
		return (false);
	}

	return (CTR_DIC_VAL(ctr) != 0);
}

static bool
get_cache_idc(uint64_t ctr)
{
	if ((cache_flags & CACHE_FLAG_IDC_OFF) != 0) {
		return (false);
	}

	return (CTR_IDC_VAL(ctr) != 0);
}

static unsigned int
get_dcache_line_size(uint64_t ctr)
{
	unsigned int dcl_size;

	/*
	 * Relevant field [19:16] is LOG2
	 * of the number of words in DCache line
	 */
	dcl_size = CTR_DLINE_SIZE(ctr);

	/* Size of word shifted by cache line size */
	return (sizeof(int) << dcl_size);
}

void
cpu_flush_dcache(const void *ptr, size_t len)
{
	uint64_t cl_size, ctr;
	vm_offset_t addr, end;

	/* Accessible from all security levels */
	ctr = READ_SPECIALREG(ctr_el0);

	if (get_cache_idc(ctr)) {
		dsb(ishst);
	} else {
		cl_size = get_dcache_line_size(ctr);

		/* Calculate end address to clean */
		end = (vm_offset_t)ptr + (vm_offset_t)len;
		/* Align start address to cache line */
		addr = (vm_offset_t)ptr;
		addr = rounddown2(addr, cl_size);

		for (; addr < end; addr += cl_size)
			__asm __volatile("dc	civac, %0" : : "r" (addr) :
			    "memory");
		/* Full system DSB */
		dsb(ish);
	}
}

void
cpu_inval_icache(void)
{
	uint64_t ctr;

	/* Accessible from all security levels */
	ctr = READ_SPECIALREG(ctr_el0);

	if (get_cache_dic(ctr)) {
		isb();
	} else {
		__asm __volatile(
		    "ic		ialluis	\n"
		    "dsb	ish	\n"
		    "isb		\n"
		    : : : "memory");
	}
}

static int
command_cache_flags(int argc, char *argv[])
{
	char *cp;
	long new_flags;

	if (argc == 3) {
		if (strcmp(argv[1], "set") == 0) {
			new_flags = strtol(argv[2], &cp, 0);
			if (cp[0] != '\0') {
				printf("Invalid flags\n");
			} else {
				printf("Setting cache flags to %#lx\n",
				    new_flags);
				cache_flags = new_flags;
				return (CMD_OK);
			}
		}
	}

	printf("usage: cache_flags set <value>\n");
	return (CMD_ERROR);
}
COMMAND_SET(cache_flags, "cache_flags", "Set cache flags", command_cache_flags);