system76-coreboot/payloads/libpayload/arch/arm/cache.c

/*
 *
 * Copyright 2013 Google Inc.
 *
 * 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.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * 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.
 *
 * cache.c: Cache maintenance routines for ARMv7-A and ARMv7-R
 *
 * Reference: ARM Architecture Reference Manual, ARMv7-A and ARMv7-R edition
 */

#include <stdint.h>

#include <arch/cache.h>
#include <arch/virtual.h>

void tlb_invalidate_all(void)
{
	/* TLBIALL includes dTLB and iTLB on systems that have them. */
	tlbiall();
	dsb();
	isb();
}

enum dcache_op {
	OP_DCCSW,
	OP_DCCISW,
	OP_DCISW,
	OP_DCCIMVAC,
	OP_DCCMVAC,
	OP_DCIMVAC,
};

unsigned int dcache_line_bytes(void)
{
	uint32_t ccsidr;
	static unsigned int line_bytes = 0;

	if (line_bytes)
		return line_bytes;

	ccsidr = read_ccsidr();
	/* [2:0] - Indicates (Log2(number of words in cache line)) - 2 */
	line_bytes = 1 << ((ccsidr & 0x7) + 2);	/* words per line */
	line_bytes *= sizeof(unsigned int);	/* bytes per line */

	return line_bytes;
}

/*
 * Do a dcache operation by modified virtual address. This is useful for
 * maintaining coherency in drivers which do DMA transfers and only need to
 * perform cache maintenance on a particular memory range rather than the
 * entire cache.
 */
static void dcache_op_mva(void const *vaddr, size_t len, enum dcache_op op)
{
	unsigned long line, linesize;
	unsigned long paddr = virt_to_phys(vaddr);

	linesize = dcache_line_bytes();
	line = paddr & ~(linesize - 1);

	dsb();
	while (line < paddr + len) {
		switch(op) {
		case OP_DCCIMVAC:
			dccimvac(line);
			break;
		case OP_DCCMVAC:
			dccmvac(line);
			break;
		case OP_DCIMVAC:
			dcimvac(line);
			break;
		default:
			break;
		}
		line += linesize;
	}
	isb();
}

void dcache_clean_by_mva(void const *addr, size_t len)
{
	dcache_op_mva(addr, len, OP_DCCMVAC);
}

void dcache_clean_invalidate_by_mva(void const *addr, size_t len)
{
	dcache_op_mva(addr, len, OP_DCCIMVAC);
}

void dcache_invalidate_by_mva(void const *addr, size_t len)
{
	dcache_op_mva(addr, len, OP_DCIMVAC);
}

/*
 * CAUTION: This implementation assumes that coreboot never uses non-identity
 * page tables for pages containing executed code. If you ever want to violate
 * this assumption, have fun figuring out the associated problems on your own.
 */
void dcache_mmu_disable(void)
{
	uint32_t sctlr;

	dcache_clean_invalidate_all();
	sctlr = read_sctlr();
	sctlr &= ~(SCTLR_C | SCTLR_M);
	write_sctlr(sctlr);
}

void dcache_mmu_enable(void)
{
	uint32_t sctlr;

	sctlr = read_sctlr();
	sctlr |= SCTLR_C | SCTLR_M;
	write_sctlr(sctlr);
}

void cache_sync_instructions(void)
{
	uint32_t sctlr;

	sctlr = read_sctlr();

	if (sctlr & SCTLR_C)
		dcache_clean_all();
	else if (sctlr & SCTLR_I)
		dcache_clean_invalidate_all();

	iciallu();		/* includes BPIALLU (architecturally) */
	dsb();
	isb();
}