system/ulib/ddk/include/ddk/io-buffer.h

// Copyright 2016 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#pragma once

#include <zircon/compiler.h>
#include <zircon/types.h>

#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>

__BEGIN_CDECLS;

typedef struct {
    zx_handle_t vmo_handle;
    size_t size;
    zx_off_t offset;
    void* virt;
    zx_paddr_t phys;
} io_buffer_t;

enum {
    IO_BUFFER_RO = ZX_VM_FLAG_PERM_READ,
    IO_BUFFER_RW = ZX_VM_FLAG_PERM_READ | ZX_VM_FLAG_PERM_WRITE,
};

// Initializes a new io_buffer
zx_status_t io_buffer_init(io_buffer_t* buffer, size_t size, uint32_t flags);
zx_status_t io_buffer_init_aligned(io_buffer_t* buffer, size_t size, uint32_t alignment_log2, uint32_t flags);

// Initializes an io_buffer base on an existing VMO.
// duplicates the provided vmo_handle - does not take ownership
zx_status_t io_buffer_init_vmo(io_buffer_t* buffer, zx_handle_t vmo_handle,
                               zx_off_t offset, uint32_t flags);

// Initializes an io_buffer that maps a given physical address
zx_status_t io_buffer_init_physical(io_buffer_t* buffer, zx_paddr_t addr, size_t size,
                                    zx_handle_t resource, uint32_t cache_policy);

zx_status_t io_buffer_cache_op(io_buffer_t* buffer, const uint32_t op,
                               const zx_off_t offset, const size_t size);
// Releases an io_buffer
void io_buffer_release(io_buffer_t* buffer);

static inline bool io_buffer_is_valid(io_buffer_t* buffer) {
    return (buffer->vmo_handle != ZX_HANDLE_INVALID);
}

static inline void* io_buffer_virt(io_buffer_t* buffer) {
    return (void*)(((uintptr_t)buffer->virt) + buffer->offset);
}

static inline zx_paddr_t io_buffer_phys(io_buffer_t* buffer) {
    return buffer->phys + buffer->offset;
}

__END_CDECLS;