linux/drivers/dma-buf/dma-heap.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Framework for userspace DMA-BUF allocations
 *
 * Copyright (C) 2011 Google, Inc.
 * Copyright (C) 2019 Linaro Ltd.
 */

#include <linux/cdev.h>
#include <linux/debugfs.h>
#include <linux/device.h>
#include <linux/dma-buf.h>
#include <linux/err.h>
#include <linux/xarray.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/nospec.h>
#include <linux/uaccess.h>
#include <linux/syscalls.h>
#include <linux/dma-heap.h>
#include <uapi/linux/dma-heap.h>

#define DEVNAME …

#define NUM_HEAP_MINORS …

/**
 * struct dma_heap - represents a dmabuf heap in the system
 * @name:		used for debugging/device-node name
 * @ops:		ops struct for this heap
 * @heap_devt		heap device node
 * @list		list head connecting to list of heaps
 * @heap_cdev		heap char device
 *
 * Represents a heap of memory from which buffers can be made.
 */
struct dma_heap { … };

static LIST_HEAD(heap_list);
static DEFINE_MUTEX(heap_list_lock);
static dev_t dma_heap_devt;
static struct class *dma_heap_class;
static DEFINE_XARRAY_ALLOC(dma_heap_minors);

static int dma_heap_buffer_alloc(struct dma_heap *heap, size_t len,
				 u32 fd_flags,
				 u64 heap_flags)
{ … }

static int dma_heap_open(struct inode *inode, struct file *file)
{ … }

static long dma_heap_ioctl_allocate(struct file *file, void *data)
{ … }

static unsigned int dma_heap_ioctl_cmds[] = …;

static long dma_heap_ioctl(struct file *file, unsigned int ucmd,
			   unsigned long arg)
{ … }

static const struct file_operations dma_heap_fops = …;

/**
 * dma_heap_get_drvdata() - get per-subdriver data for the heap
 * @heap: DMA-Heap to retrieve private data for
 *
 * Returns:
 * The per-subdriver data for the heap.
 */
void *dma_heap_get_drvdata(struct dma_heap *heap)
{ … }

/**
 * dma_heap_get_name() - get heap name
 * @heap: DMA-Heap to retrieve private data for
 *
 * Returns:
 * The char* for the heap name.
 */
const char *dma_heap_get_name(struct dma_heap *heap)
{ … }

struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info)
{ … }

static char *dma_heap_devnode(const struct device *dev, umode_t *mode)
{ … }

static int dma_heap_init(void)
{ … }
subsys_initcall(dma_heap_init);