drivers/misc/qfw.c - u-boot-mtk - Git at Google

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * (C) Copyright 2015 Miao Yan <yanmiaobest@gmail.com>
  */

 #include <common.h>
 #include <command.h>
 #include <errno.h>
 #include <malloc.h>
 #include <qfw.h>
 #include <asm/io.h>
 #ifdef CONFIG_GENERATE_ACPI_TABLE
 #include <asm/tables.h>
 #endif
 #include <linux/list.h>

 static bool fwcfg_present;
 static bool fwcfg_dma_present;
 static struct fw_cfg_arch_ops *fwcfg_arch_ops;

 static LIST_HEAD(fw_list);

 #ifdef CONFIG_GENERATE_ACPI_TABLE
 /*
  * This function allocates memory for ACPI tables
  *
  * @entry : BIOS linker command entry which tells where to allocate memory
  *          (either high memory or low memory)
  * @addr  : The address that should be used for low memory allcation. If the
  *          memory allocation request is 'ZONE_HIGH' then this parameter will
  *          be ignored.
  * @return: 0 on success, or negative value on failure
  */
 static int bios_linker_allocate(struct bios_linker_entry *entry, ulong *addr)
 {
 	uint32_t size, align;
 	struct fw_file *file;
 	unsigned long aligned_addr;

 	align = le32_to_cpu(entry->alloc.align);
 	/* align must be power of 2 */
 	if (align & (align - 1)) {
 		printf("error: wrong alignment %u\n", align);
 		return -EINVAL;
 	}

 	file = qemu_fwcfg_find_file(entry->alloc.file);
 	if (!file) {
 		printf("error: can't find file %s\n", entry->alloc.file);
 		return -ENOENT;
 	}

 	size = be32_to_cpu(file->cfg.size);

 	/*
 	 * ZONE_HIGH means we need to allocate from high memory, since
 	 * malloc space is already at the end of RAM, so we directly use it.
 	 * If allocation zone is ZONE_FSEG, then we use the 'addr' passed
 	 * in which is low memory
 	 */
 	if (entry->alloc.zone == BIOS_LINKER_LOADER_ALLOC_ZONE_HIGH) {
 		aligned_addr = (unsigned long)memalign(align, size);
 		if (!aligned_addr) {
 			printf("error: allocating resource\n");
 			return -ENOMEM;
 		}
 	} else if (entry->alloc.zone == BIOS_LINKER_LOADER_ALLOC_ZONE_FSEG) {
 		aligned_addr = ALIGN(*addr, align);
 	} else {
 		printf("error: invalid allocation zone\n");
 		return -EINVAL;
 	}

 	debug("bios_linker_allocate: allocate file %s, size %u, zone %d, align %u, addr 0x%lx\n",
 	      file->cfg.name, size, entry->alloc.zone, align, aligned_addr);

 	qemu_fwcfg_read_entry(be16_to_cpu(file->cfg.select),
 			      size, (void *)aligned_addr);
 	file->addr = aligned_addr;

 	/* adjust address for low memory allocation */
 	if (entry->alloc.zone == BIOS_LINKER_LOADER_ALLOC_ZONE_FSEG)
 		*addr = (aligned_addr + size);

 	return 0;
 }

 /*
  * This function patches ACPI tables previously loaded
  * by bios_linker_allocate()
  *
  * @entry : BIOS linker command entry which tells how to patch
  *          ACPI tables
  * @return: 0 on success, or negative value on failure
  */
 static int bios_linker_add_pointer(struct bios_linker_entry *entry)
 {
 	struct fw_file *dest, *src;
 	uint32_t offset = le32_to_cpu(entry->pointer.offset);
 	uint64_t pointer = 0;

 	dest = qemu_fwcfg_find_file(entry->pointer.dest_file);
 	if (!dest || !dest->addr)
 		return -ENOENT;
 	src = qemu_fwcfg_find_file(entry->pointer.src_file);
 	if (!src || !src->addr)
 		return -ENOENT;

 	debug("bios_linker_add_pointer: dest->addr 0x%lx, src->addr 0x%lx, offset 0x%x size %u, 0x%llx\n",
 	      dest->addr, src->addr, offset, entry->pointer.size, pointer);

 	memcpy(&pointer, (char *)dest->addr + offset, entry->pointer.size);
 	pointer	= le64_to_cpu(pointer);
 	pointer += (unsigned long)src->addr;
 	pointer	= cpu_to_le64(pointer);
 	memcpy((char *)dest->addr + offset, &pointer, entry->pointer.size);

 	return 0;
 }

 /*
  * This function updates checksum fields of ACPI tables previously loaded
  * by bios_linker_allocate()
  *
  * @entry : BIOS linker command entry which tells where to update ACPI table
  *          checksums
  * @return: 0 on success, or negative value on failure
  */
 static int bios_linker_add_checksum(struct bios_linker_entry *entry)
 {
 	struct fw_file *file;
 	uint8_t *data, cksum = 0;
 	uint8_t *cksum_start;

 	file = qemu_fwcfg_find_file(entry->cksum.file);
 	if (!file || !file->addr)
 		return -ENOENT;

 	data = (uint8_t *)(file->addr + le32_to_cpu(entry->cksum.offset));
 	cksum_start = (uint8_t *)(file->addr + le32_to_cpu(entry->cksum.start));
 	cksum = table_compute_checksum(cksum_start,
 				       le32_to_cpu(entry->cksum.length));
 	*data = cksum;

 	return 0;
 }

 /* This function loads and patches ACPI tables provided by QEMU */
 ulong write_acpi_tables(ulong addr)
 {
 	int i, ret = 0;
 	struct fw_file *file;
 	struct bios_linker_entry *table_loader;
 	struct bios_linker_entry *entry;
 	uint32_t size;

 	/* make sure fw_list is loaded */
 	ret = qemu_fwcfg_read_firmware_list();
 	if (ret) {
 		printf("error: can't read firmware file list\n");
 		return addr;
 	}

 	file = qemu_fwcfg_find_file("etc/table-loader");
 	if (!file) {
 		printf("error: can't find etc/table-loader\n");
 		return addr;
 	}

 	size = be32_to_cpu(file->cfg.size);
 	if ((size % sizeof(*entry)) != 0) {
 		printf("error: table-loader maybe corrupted\n");
 		return addr;
 	}

 	table_loader = malloc(size);
 	if (!table_loader) {
 		printf("error: no memory for table-loader\n");
 		return addr;
 	}

 	qemu_fwcfg_read_entry(be16_to_cpu(file->cfg.select),
 			      size, table_loader);

 	for (i = 0; i < (size / sizeof(*entry)); i++) {
 		entry = table_loader + i;
 		switch (le32_to_cpu(entry->command)) {
 		case BIOS_LINKER_LOADER_COMMAND_ALLOCATE:
 			ret = bios_linker_allocate(entry, &addr);
 			if (ret)
 				goto out;
 			break;
 		case BIOS_LINKER_LOADER_COMMAND_ADD_POINTER:
 			ret = bios_linker_add_pointer(entry);
 			if (ret)
 				goto out;
 			break;
 		case BIOS_LINKER_LOADER_COMMAND_ADD_CHECKSUM:
 			ret = bios_linker_add_checksum(entry);
 			if (ret)
 				goto out;
 			break;
 		default:
 			break;
 		}
 	}

 out:
 	if (ret) {
 		struct fw_cfg_file_iter iter;
 		for (file = qemu_fwcfg_file_iter_init(&iter);
 		     !qemu_fwcfg_file_iter_end(&iter);
 		     file = qemu_fwcfg_file_iter_next(&iter)) {
 			if (file->addr) {
 				free((void *)file->addr);
 				file->addr = 0;
 			}
 		}
 	}

 	free(table_loader);
 	return addr;
 }

 ulong acpi_get_rsdp_addr(void)
 {
 	struct fw_file *file;

 	file = qemu_fwcfg_find_file("etc/acpi/rsdp");
 	return file->addr;
 }
 #endif

 /* Read configuration item using fw_cfg PIO interface */
 static void qemu_fwcfg_read_entry_pio(uint16_t entry,
 		uint32_t size, void *address)
 {
 	debug("qemu_fwcfg_read_entry_pio: entry 0x%x, size %u address %p\n",
 	      entry, size, address);

 	return fwcfg_arch_ops->arch_read_pio(entry, size, address);
 }

 /* Read configuration item using fw_cfg DMA interface */
 static void qemu_fwcfg_read_entry_dma(uint16_t entry,
 		uint32_t size, void *address)
 {
 	struct fw_cfg_dma_access dma;

 	dma.length = cpu_to_be32(size);
 	dma.address = cpu_to_be64((uintptr_t)address);
 	dma.control = cpu_to_be32(FW_CFG_DMA_READ);

 	/*
 	 * writting FW_CFG_INVALID will cause read operation to resume at
 	 * last offset, otherwise read will start at offset 0
 	 */
 	if (entry != FW_CFG_INVALID)
 		dma.control |= cpu_to_be32(FW_CFG_DMA_SELECT | (entry << 16));

 	barrier();

 	debug("qemu_fwcfg_read_entry_dma: entry 0x%x, size %u address %p, control 0x%x\n",
 	      entry, size, address, be32_to_cpu(dma.control));

 	fwcfg_arch_ops->arch_read_dma(&dma);
 }

 bool qemu_fwcfg_present(void)
 {
 	return fwcfg_present;
 }

 bool qemu_fwcfg_dma_present(void)
 {
 	return fwcfg_dma_present;
 }

 void qemu_fwcfg_read_entry(uint16_t entry, uint32_t length, void *address)
 {
 	if (fwcfg_dma_present)
 		qemu_fwcfg_read_entry_dma(entry, length, address);
 	else
 		qemu_fwcfg_read_entry_pio(entry, length, address);
 }

 int qemu_fwcfg_online_cpus(void)
 {
 	uint16_t nb_cpus;

 	if (!fwcfg_present)
 		return -ENODEV;

 	qemu_fwcfg_read_entry(FW_CFG_NB_CPUS, 2, &nb_cpus);

 	return le16_to_cpu(nb_cpus);
 }

 int qemu_fwcfg_read_firmware_list(void)
 {
 	int i;
 	uint32_t count;
 	struct fw_file *file;
 	struct list_head *entry;

 	/* don't read it twice */
 	if (!list_empty(&fw_list))
 		return 0;

 	qemu_fwcfg_read_entry(FW_CFG_FILE_DIR, 4, &count);
 	if (!count)
 		return 0;

 	count = be32_to_cpu(count);
 	for (i = 0; i < count; i++) {
 		file = malloc(sizeof(*file));
 		if (!file) {
 			printf("error: allocating resource\n");
 			goto err;
 		}
 		qemu_fwcfg_read_entry(FW_CFG_INVALID,
 				      sizeof(struct fw_cfg_file), &file->cfg);
 		file->addr = 0;
 		list_add_tail(&file->list, &fw_list);
 	}

 	return 0;

 err:
 	list_for_each(entry, &fw_list) {
 		file = list_entry(entry, struct fw_file, list);
 		free(file);
 	}

 	return -ENOMEM;
 }

 struct fw_file *qemu_fwcfg_find_file(const char *name)
 {
 	struct list_head *entry;
 	struct fw_file *file;

 	list_for_each(entry, &fw_list) {
 		file = list_entry(entry, struct fw_file, list);
 		if (!strcmp(file->cfg.name, name))
 			return file;
 	}

 	return NULL;
 }

 struct fw_file *qemu_fwcfg_file_iter_init(struct fw_cfg_file_iter *iter)
 {
 	iter->entry = fw_list.next;
 	return list_entry((struct list_head *)iter->entry,
 			  struct fw_file, list);
 }

 struct fw_file *qemu_fwcfg_file_iter_next(struct fw_cfg_file_iter *iter)
 {
 	iter->entry = ((struct list_head *)iter->entry)->next;
 	return list_entry((struct list_head *)iter->entry,
 			  struct fw_file, list);
 }

 bool qemu_fwcfg_file_iter_end(struct fw_cfg_file_iter *iter)
 {
 	return iter->entry == &fw_list;
 }

 void qemu_fwcfg_init(struct fw_cfg_arch_ops *ops)
 {
 	uint32_t qemu;
 	uint32_t dma_enabled;

 	fwcfg_present = false;
 	fwcfg_dma_present = false;
 	fwcfg_arch_ops = NULL;

 	if (!ops || !ops->arch_read_pio || !ops->arch_read_dma)
 		return;
 	fwcfg_arch_ops = ops;

 	qemu_fwcfg_read_entry_pio(FW_CFG_SIGNATURE, 4, &qemu);
 	if (be32_to_cpu(qemu) == QEMU_FW_CFG_SIGNATURE)
 		fwcfg_present = true;

 	if (fwcfg_present) {
 		qemu_fwcfg_read_entry_pio(FW_CFG_ID, 1, &dma_enabled);
 		if (dma_enabled & FW_CFG_DMA_ENABLED)
 			fwcfg_dma_present = true;
 	}
 }
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* (C) Copyright 2015 Miao Yan <yanmiaobest@gmail.com>
	*/

	#include <common.h>
	#include <command.h>
	#include <errno.h>
	#include <malloc.h>
	#include <qfw.h>
	#include <asm/io.h>
	#ifdef CONFIG_GENERATE_ACPI_TABLE
	#include <asm/tables.h>
	#endif
	#include <linux/list.h>

	static bool fwcfg_present;
	static bool fwcfg_dma_present;
	static struct fw_cfg_arch_ops *fwcfg_arch_ops;

	static LIST_HEAD(fw_list);

	#ifdef CONFIG_GENERATE_ACPI_TABLE
	/*
	* This function allocates memory for ACPI tables
	*
	* @entry : BIOS linker command entry which tells where to allocate memory
	* (either high memory or low memory)
	* @addr : The address that should be used for low memory allcation. If the
	* memory allocation request is 'ZONE_HIGH' then this parameter will
	* be ignored.
	* @return: 0 on success, or negative value on failure
	*/
	static int bios_linker_allocate(struct bios_linker_entry entry, ulong addr)
	{
	uint32_t size, align;
	struct fw_file *file;
	unsigned long aligned_addr;

	align = le32_to_cpu(entry->alloc.align);
	/* align must be power of 2 */
	if (align & (align - 1)) {
	printf("error: wrong alignment %u\n", align);
	return -EINVAL;
	}

	file = qemu_fwcfg_find_file(entry->alloc.file);
	if (!file) {
	printf("error: can't find file %s\n", entry->alloc.file);
	return -ENOENT;
	}

	size = be32_to_cpu(file->cfg.size);

	/*
	* ZONE_HIGH means we need to allocate from high memory, since
	* malloc space is already at the end of RAM, so we directly use it.
	* If allocation zone is ZONE_FSEG, then we use the 'addr' passed
	* in which is low memory
	*/
	if (entry->alloc.zone == BIOS_LINKER_LOADER_ALLOC_ZONE_HIGH) {
	aligned_addr = (unsigned long)memalign(align, size);
	if (!aligned_addr) {
	printf("error: allocating resource\n");
	return -ENOMEM;
	}
	} else if (entry->alloc.zone == BIOS_LINKER_LOADER_ALLOC_ZONE_FSEG) {
	aligned_addr = ALIGN(*addr, align);
	} else {
	printf("error: invalid allocation zone\n");
	return -EINVAL;
	}

	debug("bios_linker_allocate: allocate file %s, size %u, zone %d, align %u, addr 0x%lx\n",
	file->cfg.name, size, entry->alloc.zone, align, aligned_addr);

	qemu_fwcfg_read_entry(be16_to_cpu(file->cfg.select),
	size, (void *)aligned_addr);
	file->addr = aligned_addr;

	/* adjust address for low memory allocation */
	if (entry->alloc.zone == BIOS_LINKER_LOADER_ALLOC_ZONE_FSEG)
	*addr = (aligned_addr + size);

	return 0;
	}

	/*
	* This function patches ACPI tables previously loaded
	* by bios_linker_allocate()
	*
	* @entry : BIOS linker command entry which tells how to patch
	* ACPI tables
	* @return: 0 on success, or negative value on failure
	*/
	static int bios_linker_add_pointer(struct bios_linker_entry *entry)
	{
	struct fw_file dest, src;
	uint32_t offset = le32_to_cpu(entry->pointer.offset);
	uint64_t pointer = 0;

	dest = qemu_fwcfg_find_file(entry->pointer.dest_file);
	if (!dest \|\| !dest->addr)
	return -ENOENT;
	src = qemu_fwcfg_find_file(entry->pointer.src_file);
	if (!src \|\| !src->addr)
	return -ENOENT;

	debug("bios_linker_add_pointer: dest->addr 0x%lx, src->addr 0x%lx, offset 0x%x size %u, 0x%llx\n",
	dest->addr, src->addr, offset, entry->pointer.size, pointer);

	memcpy(&pointer, (char *)dest->addr + offset, entry->pointer.size);
	pointer = le64_to_cpu(pointer);
	pointer += (unsigned long)src->addr;
	pointer = cpu_to_le64(pointer);
	memcpy((char *)dest->addr + offset, &pointer, entry->pointer.size);

	return 0;
	}

	/*
	* This function updates checksum fields of ACPI tables previously loaded
	* by bios_linker_allocate()
	*
	* @entry : BIOS linker command entry which tells where to update ACPI table
	* checksums
	* @return: 0 on success, or negative value on failure
	*/
	static int bios_linker_add_checksum(struct bios_linker_entry *entry)
	{
	struct fw_file *file;
	uint8_t *data, cksum = 0;
	uint8_t *cksum_start;

	file = qemu_fwcfg_find_file(entry->cksum.file);
	if (!file \|\| !file->addr)
	return -ENOENT;

	data = (uint8_t *)(file->addr + le32_to_cpu(entry->cksum.offset));
	cksum_start = (uint8_t *)(file->addr + le32_to_cpu(entry->cksum.start));
	cksum = table_compute_checksum(cksum_start,
	le32_to_cpu(entry->cksum.length));
	*data = cksum;

	return 0;
	}

	/* This function loads and patches ACPI tables provided by QEMU */
	ulong write_acpi_tables(ulong addr)
	{
	int i, ret = 0;
	struct fw_file *file;
	struct bios_linker_entry *table_loader;
	struct bios_linker_entry *entry;
	uint32_t size;

	/* make sure fw_list is loaded */
	ret = qemu_fwcfg_read_firmware_list();
	if (ret) {
	printf("error: can't read firmware file list\n");
	return addr;
	}

	file = qemu_fwcfg_find_file("etc/table-loader");
	if (!file) {
	printf("error: can't find etc/table-loader\n");
	return addr;
	}

	size = be32_to_cpu(file->cfg.size);
	if ((size % sizeof(*entry)) != 0) {
	printf("error: table-loader maybe corrupted\n");
	return addr;
	}

	table_loader = malloc(size);
	if (!table_loader) {
	printf("error: no memory for table-loader\n");
	return addr;
	}

	qemu_fwcfg_read_entry(be16_to_cpu(file->cfg.select),
	size, table_loader);

	for (i = 0; i < (size / sizeof(*entry)); i++) {
	entry = table_loader + i;
	switch (le32_to_cpu(entry->command)) {
	case BIOS_LINKER_LOADER_COMMAND_ALLOCATE:
	ret = bios_linker_allocate(entry, &addr);
	if (ret)
	goto out;
	break;
	case BIOS_LINKER_LOADER_COMMAND_ADD_POINTER:
	ret = bios_linker_add_pointer(entry);
	if (ret)
	goto out;
	break;
	case BIOS_LINKER_LOADER_COMMAND_ADD_CHECKSUM:
	ret = bios_linker_add_checksum(entry);
	if (ret)
	goto out;
	break;
	default:
	break;
	}
	}

	out:
	if (ret) {
	struct fw_cfg_file_iter iter;
	for (file = qemu_fwcfg_file_iter_init(&iter);
	!qemu_fwcfg_file_iter_end(&iter);
	file = qemu_fwcfg_file_iter_next(&iter)) {
	if (file->addr) {
	free((void *)file->addr);
	file->addr = 0;
	}
	}
	}

	free(table_loader);
	return addr;
	}

	ulong acpi_get_rsdp_addr(void)
	{
	struct fw_file *file;

	file = qemu_fwcfg_find_file("etc/acpi/rsdp");
	return file->addr;
	}
	#endif

	/* Read configuration item using fw_cfg PIO interface */
	static void qemu_fwcfg_read_entry_pio(uint16_t entry,
	uint32_t size, void *address)
	{
	debug("qemu_fwcfg_read_entry_pio: entry 0x%x, size %u address %p\n",
	entry, size, address);

	return fwcfg_arch_ops->arch_read_pio(entry, size, address);
	}

	/* Read configuration item using fw_cfg DMA interface */
	static void qemu_fwcfg_read_entry_dma(uint16_t entry,
	uint32_t size, void *address)
	{
	struct fw_cfg_dma_access dma;

	dma.length = cpu_to_be32(size);
	dma.address = cpu_to_be64((uintptr_t)address);
	dma.control = cpu_to_be32(FW_CFG_DMA_READ);

	/*
	* writting FW_CFG_INVALID will cause read operation to resume at
	* last offset, otherwise read will start at offset 0
	*/
	if (entry != FW_CFG_INVALID)
	dma.control \|= cpu_to_be32(FW_CFG_DMA_SELECT \| (entry << 16));

	barrier();

	debug("qemu_fwcfg_read_entry_dma: entry 0x%x, size %u address %p, control 0x%x\n",
	entry, size, address, be32_to_cpu(dma.control));

	fwcfg_arch_ops->arch_read_dma(&dma);
	}

	bool qemu_fwcfg_present(void)
	{
	return fwcfg_present;
	}

	bool qemu_fwcfg_dma_present(void)
	{
	return fwcfg_dma_present;
	}

	void qemu_fwcfg_read_entry(uint16_t entry, uint32_t length, void *address)
	{
	if (fwcfg_dma_present)
	qemu_fwcfg_read_entry_dma(entry, length, address);
	else
	qemu_fwcfg_read_entry_pio(entry, length, address);
	}

	int qemu_fwcfg_online_cpus(void)
	{
	uint16_t nb_cpus;

	if (!fwcfg_present)
	return -ENODEV;

	qemu_fwcfg_read_entry(FW_CFG_NB_CPUS, 2, &nb_cpus);

	return le16_to_cpu(nb_cpus);
	}

	int qemu_fwcfg_read_firmware_list(void)
	{
	int i;
	uint32_t count;
	struct fw_file *file;
	struct list_head *entry;

	/* don't read it twice */
	if (!list_empty(&fw_list))
	return 0;

	qemu_fwcfg_read_entry(FW_CFG_FILE_DIR, 4, &count);
	if (!count)
	return 0;

	count = be32_to_cpu(count);
	for (i = 0; i < count; i++) {
	file = malloc(sizeof(*file));
	if (!file) {
	printf("error: allocating resource\n");
	goto err;
	}
	qemu_fwcfg_read_entry(FW_CFG_INVALID,
	sizeof(struct fw_cfg_file), &file->cfg);
	file->addr = 0;
	list_add_tail(&file->list, &fw_list);
	}

	return 0;

	err:
	list_for_each(entry, &fw_list) {
	file = list_entry(entry, struct fw_file, list);
	free(file);
	}

	return -ENOMEM;
	}

	struct fw_file qemu_fwcfg_find_file(const char name)
	{
	struct list_head *entry;
	struct fw_file *file;

	list_for_each(entry, &fw_list) {
	file = list_entry(entry, struct fw_file, list);
	if (!strcmp(file->cfg.name, name))
	return file;
	}

	return NULL;
	}

	struct fw_file qemu_fwcfg_file_iter_init(struct fw_cfg_file_iter iter)
	{
	iter->entry = fw_list.next;
	return list_entry((struct list_head *)iter->entry,
	struct fw_file, list);
	}

	struct fw_file qemu_fwcfg_file_iter_next(struct fw_cfg_file_iter iter)
	{
	iter->entry = ((struct list_head *)iter->entry)->next;
	return list_entry((struct list_head *)iter->entry,
	struct fw_file, list);
	}

	bool qemu_fwcfg_file_iter_end(struct fw_cfg_file_iter *iter)
	{
	return iter->entry == &fw_list;
	}

	void qemu_fwcfg_init(struct fw_cfg_arch_ops *ops)
	{
	uint32_t qemu;
	uint32_t dma_enabled;

	fwcfg_present = false;
	fwcfg_dma_present = false;
	fwcfg_arch_ops = NULL;

	if (!ops \|\| !ops->arch_read_pio \|\| !ops->arch_read_dma)
	return;
	fwcfg_arch_ops = ops;

	qemu_fwcfg_read_entry_pio(FW_CFG_SIGNATURE, 4, &qemu);
	if (be32_to_cpu(qemu) == QEMU_FW_CFG_SIGNATURE)
	fwcfg_present = true;

	if (fwcfg_present) {
	qemu_fwcfg_read_entry_pio(FW_CFG_ID, 1, &dma_enabled);
	if (dma_enabled & FW_CFG_DMA_ENABLED)
	fwcfg_dma_present = true;
	}
	}