include/lmb.h

/* SPDX-License-Identifier: GPL-2.0+ */
/*
 * Logical memory blocks.
 *
 * Copyright (C) 2001 Peter Bergner, IBM Corp.
 */

#ifndef _LINUX_LMB_H
#define _LINUX_LMB_H

#ifdef __KERNEL__

#include <alist.h>
#include <asm/types.h>
#include <asm/u-boot.h>
#include <linux/bitops.h>

#define LMB_ALLOC_ANYWHERE	0
#define LMB_ALIST_INITIAL_SIZE	4

/**
 * define LMB_NONE - no special request
 *
 * LMB Memory region attribute flag to indicate that there are no special
 * requests for this region. Normally used as a placeholder value.
 */
#define LMB_NONE 0

/**
 * define LMB_NOMAP - do not add to MMU configuration
 *
 * LMB Memory region attribute flag to indicate that the region will not be
 * mapped by LMB. Normally used for reserved regions.
 */
#define LMB_NOMAP BIT(1)

/**
 * define LMB_NOOVERWRITE - do not overwrite/re-reserve
 *
 * LMB Memory region attribute flag to indicate that the region will not be
 * overwritten or re-reserved. Normally used for reserved regions.
 */
#define LMB_NOOVERWRITE BIT(2)

/**
 * define LMB_NONOTIFY - do not notify other modules of changes
 *
 * LMB Memory region attribute flag to indicate that the region will not notify
 * downstream allocators (currently just the EFI allocator) of changes to this
 * region through lmb_map_update_notify().
 */
#define LMB_NONOTIFY BIT(3)

/**
 * enum lmb_mem_type - type of memory allocation request
 * @LMB_MEM_ALLOC_ADDR:	request for a particular region of memory
 * @LMB_MEM_ALLOC_ANY:	allocate any available memory region
 * @LMB_MEM_ALLOC_MAX:	allocate memory below a particular address
 */
enum lmb_mem_type {
	LMB_MEM_ALLOC_ADDR = 1,
	LMB_MEM_ALLOC_ANY,
	LMB_MEM_ALLOC_MAX,
};

/**
 * enum lmb_map_op - memory map operation
 */
enum lmb_map_op {
	/** @LMB_MAP_OP_RESERVE:	reserve memory */
	LMB_MAP_OP_RESERVE = 1,
	/** @LMB_MAP_OP_FREE:		free memory */
	LMB_MAP_OP_FREE,
	/** @LMB_MAP_OP_ADD:		add memory */
	LMB_MAP_OP_ADD,
};

/**
 * struct lmb_region - Description of one region
 * @base: Base address of the region
 * @size: Size of the region
 * @flags: Memory region attributes
 */
struct lmb_region {
	phys_addr_t base;
	phys_size_t size;
	u32 flags;
};

/**
 * struct lmb - The LMB structure
 * @available_mem: List of memory available to LMB
 * @used_mem: List of used/reserved memory regions
 * @test: Is structure being used for LMB tests
 */
struct lmb {
	struct alist available_mem;
	struct alist used_mem;
	bool test;
};

/**
 * lmb_alloc_mem() - Request LMB memory
 * @type:		Type of memory allocation request
 * @align:		Alignment of the memory region requested(0 for none)
 * @addr:		Base address of the allocated memory region
 * @size:		Size in bytes of the allocation request
 * @flags:		Memory region attributes to be set
 *
 * Allocate a region of memory where the allocation is based on the parameters
 * that have been passed to the function.The first parameter specifies the
 * type of allocation that is being requested. The second parameter, @align
 * is used to specify if the allocation is to be made with a particular
 * alignment. Use 0 for no alignment requirements.
 *
 * The allocated address is returned through the @addr parameter when @type
 * is @LMB_MEM_ALLOC_ANY or @LMB_MEM_ALLOC_MAX. If @type is
 * @LMB_MEM_ALLOC_ADDR the @addr parameter would contain the address being
 * requested.
 *
 * The flags parameter is used to specify the memory attributes of the
 * requested region.
 *
 * Return: 0 on success, -ve value on failure
 *
 * When the allocation is of type @LMB_MEM_ALLOC_ADDR, the return value can
 * be -EINVAL if the requested memory region is not part of the LMB memory
 * map, and -EEXIST if the requested region is already allocated.
 */
int lmb_alloc_mem(enum lmb_mem_type type, u64 align, phys_addr_t *addr,
		  phys_size_t size, u32 flags);

/**
 * lmb_init() - Initialise the LMB module.
 *
 * Return: 0 on success, negative error code on failure.
 *
 * Initialise the LMB lists needed for keeping the memory map. There
 * are two lists, in form of allocated list data structure. One for the
 * available memory, and one for the used memory. Initialise the two
 * lists as part of board init. Add memory to the available memory
 * list and reserve common areas by adding them to the used memory
 * list.
 */
int lmb_init(void);

long lmb_add(phys_addr_t base, phys_size_t size);

phys_size_t lmb_get_free_size(phys_addr_t addr);

/**
 * lmb_is_reserved_flags() - Test if address is in reserved region with flag
 *			     bits set
 * @addr: Address to be tested
 * @flags: Bitmap with bits to be tested
 *
 * The function checks if a reserved region comprising @addr exists which has
 * all flag bits set which are set in @flags.
 *
 * Return: 1 if matching reservation exists, 0 otherwise.
 */
int lmb_is_reserved_flags(phys_addr_t addr, int flags);

/**
 * lmb_free() - Free up a region of memory
 * @base: Base Address of region to be freed
 * @size: Size of the region to be freed
 * @flags: Memory region attributes
 *
 * Return: 0 on success, negative error code on failure.
 */
long lmb_free(phys_addr_t base, phys_size_t size, u32 flags);

void lmb_dump_all(void);
void lmb_dump_all_force(void);

void lmb_arch_add_memory(void);

struct lmb *lmb_get(void);
int lmb_push(struct lmb *store);
void lmb_pop(struct lmb *store);

static inline int lmb_read_check(phys_addr_t addr, phys_size_t len)
{
	return lmb_alloc_mem(LMB_MEM_ALLOC_ADDR, 0, &addr, len, LMB_NONE);
}

/**
 * io_lmb_setup() - Initialize LMB struct
 * @io_lmb: IO LMB to initialize
 *
 * Return: 0 on success, negative error code on failure.
 */
int io_lmb_setup(struct lmb *io_lmb);

/**
 * io_lmb_teardown() - Tear LMB struct down
 * @io_lmb: IO LMB to teardown
 */
void io_lmb_teardown(struct lmb *io_lmb);

/**
 * io_lmb_add() - Add an IOVA range for allocations
 * @io_lmb: LMB to add the space to
 * @base: Base Address of region to add
 * @size: Size of the region to add
 *
 * Add the IOVA space [base, base + size] to be managed by io_lmb.
 *
 * Return: 0 on success, negative error code on failure.
 */
long io_lmb_add(struct lmb *io_lmb, phys_addr_t base, phys_size_t size);

/**
 * io_lmb_alloc() - Allocate specified IO memory address with specified
 *		    alignment
 * @io_lmb: LMB to alloc from
 * @size: Size of the region requested
 * @align: Required address and size alignment
 *
 * Allocate a region of IO memory. The base parameter is used to specify the
 * base address of the requested region.
 *
 * Return: Base IO address on success, 0 on error.
 */
phys_addr_t io_lmb_alloc(struct lmb *io_lmb, phys_size_t size, ulong align);

/**
 * io_lmb_free() - Free up a region of IOVA space
 * @io_lmb: LMB to return the IO address space to
 * @base: Base Address of region to be freed
 * @size: Size of the region to be freed
 *
 * Return: 0 on success, negative error code on failure.
 */
long io_lmb_free(struct lmb *io_lmb, phys_addr_t base, phys_size_t size);

#endif /* __KERNEL__ */

#endif /* _LINUX_LMB_H */