/*
 * Copyright (c) 2007 Michal Kebrt
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - 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.
 * - 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 ``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 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.
 */

/** @addtogroup kernel_arm32_mm
 * @{
 */
/** @file
 *  @brief TLB related functions.
 */

#include <mm/tlb.h>
#include <arch/mm/asid.h>
#include <arch/asm.h>
#include <arch/cp15.h>
#include <typedefs.h>
#include <arch/mm/page.h>
#include <arch/cache.h>
#include <arch/barrier.h>

/** Invalidate all entries in TLB.
 *
 * @note See ARM Architecture reference section 3.7.7 for details.
 */
void tlb_invalidate_all(void)
{
	TLBIALL_write(0);
	/*
	 * "A TLB maintenance operation is only guaranteed to be complete after
	 * the execution of a DSB instruction."
	 * "An ISB instruction, or a return from an exception, causes the
	 * effect of all completed TLB maintenance operations that appear in
	 * program order before the ISB or return from exception to be visible
	 * to all subsequent instructions, including the instruction fetches
	 * for those instructions."
	 * ARM Architecture reference Manual ch. B3.10.1 p. B3-1374 B3-1375
	 */
	dsb();
	isb();
}

/** Invalidate all entries in TLB that belong to specified address space.
 *
 * @param asid Ignored as the ARM architecture doesn't support ASIDs.
 */
void tlb_invalidate_asid(asid_t asid)
{
	tlb_invalidate_all();
	// TODO: why not TLBIASID_write(asid) ?
}

/** Invalidate single entry in TLB
 *
 * @param page Virtual address of the page
 */
static inline void invalidate_page(uintptr_t page)
{
#if defined(PROCESSOR_ARCH_armv6) || defined(PROCESSOR_ARCH_armv7_a)
	if (TLBTR_read() & TLBTR_SEP_FLAG) {
		ITLBIMVA_write(page);
		DTLBIMVA_write(page);
	} else {
		TLBIMVA_write(page);
	}
#elif defined(PROCESSOR_arm920t)
	ITLBIMVA_write(page);
	DTLBIMVA_write(page);
#elif defined(PROCESSOR_arm926ej_s)
	TLBIMVA_write(page);
#else
#error Unknown TLB type
#endif

	/*
	 * "A TLB maintenance operation is only guaranteed to be complete after
	 * the execution of a DSB instruction."
	 * "An ISB instruction, or a return from an exception, causes the
	 * effect of all completed TLB maintenance operations that appear in
	 * program order before the ISB or return from exception to be visible
	 * to all subsequent instructions, including the instruction fetches
	 * for those instructions."
	 * ARM Architecture reference Manual ch. B3.10.1 p. B3-1374 B3-1375
	 */
	dsb();
	isb();
}

/** Invalidate TLB entries for specified page range belonging to specified
 * address space.
 *
 * @param asid Ignored as the ARM architecture doesn't support it.
 * @param page Address of the first page whose entry is to be invalidated.
 * @param cnt Number of entries to invalidate.
 */
void tlb_invalidate_pages(asid_t asid __attribute__((unused)), uintptr_t page, size_t cnt)
{
	for (unsigned i = 0; i < cnt; i++)
		invalidate_page(page + i * PAGE_SIZE);
}

void tlb_arch_init(void)
{
}

void tlb_print(void)
{
}

/** @}
 */
