2019-12-03 20:26:37 +03:00
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Framework for userspace DMA-BUF allocations
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*
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* Copyright (C) 2011 Google, Inc.
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* Copyright (C) 2019 Linaro Ltd.
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*/
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#include <linux/cdev.h>
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#include <linux/debugfs.h>
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#include <linux/device.h>
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#include <linux/dma-buf.h>
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#include <linux/err.h>
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#include <linux/xarray.h>
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#include <linux/list.h>
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#include <linux/slab.h>
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2022-01-29 18:06:04 +03:00
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#include <linux/nospec.h>
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2019-12-03 20:26:37 +03:00
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#include <linux/uaccess.h>
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#include <linux/syscalls.h>
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#include <linux/dma-heap.h>
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#include <uapi/linux/dma-heap.h>
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#define DEVNAME "dma_heap"
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#define NUM_HEAP_MINORS 128
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/**
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* struct dma_heap - represents a dmabuf heap in the system
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* @name: used for debugging/device-node name
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* @ops: ops struct for this heap
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* @heap_devt heap device node
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* @list list head connecting to list of heaps
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* @heap_cdev heap char device
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*
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* Represents a heap of memory from which buffers can be made.
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*/
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struct dma_heap {
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const char *name;
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const struct dma_heap_ops *ops;
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void *priv;
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dev_t heap_devt;
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struct list_head list;
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struct cdev heap_cdev;
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};
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static LIST_HEAD(heap_list);
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static DEFINE_MUTEX(heap_list_lock);
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static dev_t dma_heap_devt;
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static struct class *dma_heap_class;
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static DEFINE_XARRAY_ALLOC(dma_heap_minors);
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static int dma_heap_buffer_alloc(struct dma_heap *heap, size_t len,
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unsigned int fd_flags,
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unsigned int heap_flags)
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{
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2021-01-19 23:45:08 +03:00
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struct dma_buf *dmabuf;
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int fd;
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2019-12-03 20:26:37 +03:00
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/*
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* Allocations from all heaps have to begin
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* and end on page boundaries.
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*/
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len = PAGE_ALIGN(len);
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if (!len)
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return -EINVAL;
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2021-01-19 23:45:08 +03:00
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dmabuf = heap->ops->allocate(heap, len, fd_flags, heap_flags);
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if (IS_ERR(dmabuf))
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return PTR_ERR(dmabuf);
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fd = dma_buf_fd(dmabuf, fd_flags);
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if (fd < 0) {
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dma_buf_put(dmabuf);
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/* just return, as put will call release and that will free */
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}
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return fd;
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2019-12-03 20:26:37 +03:00
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}
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static int dma_heap_open(struct inode *inode, struct file *file)
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{
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struct dma_heap *heap;
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heap = xa_load(&dma_heap_minors, iminor(inode));
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if (!heap) {
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pr_err("dma_heap: minor %d unknown.\n", iminor(inode));
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return -ENODEV;
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}
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/* instance data as context */
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file->private_data = heap;
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nonseekable_open(inode, file);
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return 0;
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}
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static long dma_heap_ioctl_allocate(struct file *file, void *data)
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{
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struct dma_heap_allocation_data *heap_allocation = data;
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struct dma_heap *heap = file->private_data;
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int fd;
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if (heap_allocation->fd)
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return -EINVAL;
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if (heap_allocation->fd_flags & ~DMA_HEAP_VALID_FD_FLAGS)
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return -EINVAL;
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if (heap_allocation->heap_flags & ~DMA_HEAP_VALID_HEAP_FLAGS)
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return -EINVAL;
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fd = dma_heap_buffer_alloc(heap, heap_allocation->len,
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heap_allocation->fd_flags,
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heap_allocation->heap_flags);
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if (fd < 0)
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return fd;
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heap_allocation->fd = fd;
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return 0;
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}
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2019-12-17 22:08:22 +03:00
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static unsigned int dma_heap_ioctl_cmds[] = {
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2019-12-16 16:34:04 +03:00
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DMA_HEAP_IOCTL_ALLOC,
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2019-12-03 20:26:37 +03:00
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};
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static long dma_heap_ioctl(struct file *file, unsigned int ucmd,
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unsigned long arg)
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{
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char stack_kdata[128];
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char *kdata = stack_kdata;
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unsigned int kcmd;
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unsigned int in_size, out_size, drv_size, ksize;
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int nr = _IOC_NR(ucmd);
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int ret = 0;
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if (nr >= ARRAY_SIZE(dma_heap_ioctl_cmds))
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return -EINVAL;
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2022-01-29 18:06:04 +03:00
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nr = array_index_nospec(nr, ARRAY_SIZE(dma_heap_ioctl_cmds));
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2019-12-03 20:26:37 +03:00
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/* Get the kernel ioctl cmd that matches */
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kcmd = dma_heap_ioctl_cmds[nr];
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/* Figure out the delta between user cmd size and kernel cmd size */
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drv_size = _IOC_SIZE(kcmd);
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out_size = _IOC_SIZE(ucmd);
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in_size = out_size;
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if ((ucmd & kcmd & IOC_IN) == 0)
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in_size = 0;
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if ((ucmd & kcmd & IOC_OUT) == 0)
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out_size = 0;
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ksize = max(max(in_size, out_size), drv_size);
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/* If necessary, allocate buffer for ioctl argument */
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if (ksize > sizeof(stack_kdata)) {
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kdata = kmalloc(ksize, GFP_KERNEL);
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if (!kdata)
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return -ENOMEM;
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}
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if (copy_from_user(kdata, (void __user *)arg, in_size) != 0) {
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ret = -EFAULT;
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goto err;
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}
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/* zero out any difference between the kernel/user structure size */
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if (ksize > in_size)
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memset(kdata + in_size, 0, ksize - in_size);
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switch (kcmd) {
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2019-12-16 16:34:04 +03:00
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case DMA_HEAP_IOCTL_ALLOC:
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2019-12-03 20:26:37 +03:00
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ret = dma_heap_ioctl_allocate(file, kdata);
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break;
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default:
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2019-12-16 19:10:59 +03:00
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ret = -ENOTTY;
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goto err;
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2019-12-03 20:26:37 +03:00
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}
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if (copy_to_user((void __user *)arg, kdata, out_size) != 0)
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ret = -EFAULT;
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err:
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if (kdata != stack_kdata)
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kfree(kdata);
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return ret;
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}
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static const struct file_operations dma_heap_fops = {
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.owner = THIS_MODULE,
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.open = dma_heap_open,
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.unlocked_ioctl = dma_heap_ioctl,
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#ifdef CONFIG_COMPAT
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.compat_ioctl = dma_heap_ioctl,
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#endif
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};
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/**
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* dma_heap_get_drvdata() - get per-subdriver data for the heap
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* @heap: DMA-Heap to retrieve private data for
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*
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* Returns:
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* The per-subdriver data for the heap.
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*/
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void *dma_heap_get_drvdata(struct dma_heap *heap)
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{
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return heap->priv;
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}
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2021-02-09 22:48:17 +03:00
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/**
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* dma_heap_get_name() - get heap name
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* @heap: DMA-Heap to retrieve private data for
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*
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* Returns:
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* The char* for the heap name.
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*/
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const char *dma_heap_get_name(struct dma_heap *heap)
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{
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return heap->name;
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}
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2019-12-03 20:26:37 +03:00
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struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info)
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{
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struct dma_heap *heap, *h, *err_ret;
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struct device *dev_ret;
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unsigned int minor;
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int ret;
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if (!exp_info->name || !strcmp(exp_info->name, "")) {
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pr_err("dma_heap: Cannot add heap without a name\n");
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return ERR_PTR(-EINVAL);
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}
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if (!exp_info->ops || !exp_info->ops->allocate) {
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pr_err("dma_heap: Cannot add heap with invalid ops struct\n");
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return ERR_PTR(-EINVAL);
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}
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heap = kzalloc(sizeof(*heap), GFP_KERNEL);
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if (!heap)
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return ERR_PTR(-ENOMEM);
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heap->name = exp_info->name;
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heap->ops = exp_info->ops;
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heap->priv = exp_info->priv;
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/* Find unused minor number */
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ret = xa_alloc(&dma_heap_minors, &minor, heap,
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XA_LIMIT(0, NUM_HEAP_MINORS - 1), GFP_KERNEL);
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if (ret < 0) {
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pr_err("dma_heap: Unable to get minor number for heap\n");
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err_ret = ERR_PTR(ret);
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goto err0;
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}
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/* Create device */
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heap->heap_devt = MKDEV(MAJOR(dma_heap_devt), minor);
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cdev_init(&heap->heap_cdev, &dma_heap_fops);
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ret = cdev_add(&heap->heap_cdev, heap->heap_devt, 1);
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if (ret < 0) {
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pr_err("dma_heap: Unable to add char device\n");
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err_ret = ERR_PTR(ret);
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goto err1;
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}
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dev_ret = device_create(dma_heap_class,
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NULL,
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heap->heap_devt,
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NULL,
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heap->name);
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if (IS_ERR(dev_ret)) {
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pr_err("dma_heap: Unable to create device\n");
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err_ret = ERR_CAST(dev_ret);
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goto err2;
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}
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2022-11-04 19:05:36 +03:00
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2019-12-03 20:26:37 +03:00
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mutex_lock(&heap_list_lock);
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2022-11-04 19:05:36 +03:00
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/* check the name is unique */
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list_for_each_entry(h, &heap_list, list) {
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if (!strcmp(h->name, exp_info->name)) {
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mutex_unlock(&heap_list_lock);
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pr_err("dma_heap: Already registered heap named %s\n",
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exp_info->name);
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err_ret = ERR_PTR(-EINVAL);
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goto err3;
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}
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}
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/* Add heap to the list */
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2019-12-03 20:26:37 +03:00
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list_add(&heap->list, &heap_list);
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mutex_unlock(&heap_list_lock);
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return heap;
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2022-11-04 19:05:36 +03:00
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err3:
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device_destroy(dma_heap_class, heap->heap_devt);
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2019-12-03 20:26:37 +03:00
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err2:
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cdev_del(&heap->heap_cdev);
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err1:
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xa_erase(&dma_heap_minors, minor);
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err0:
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kfree(heap);
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return err_ret;
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}
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2022-11-23 15:25:20 +03:00
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static char *dma_heap_devnode(const struct device *dev, umode_t *mode)
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2019-12-03 20:26:37 +03:00
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{
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return kasprintf(GFP_KERNEL, "dma_heap/%s", dev_name(dev));
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}
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static int dma_heap_init(void)
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{
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int ret;
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ret = alloc_chrdev_region(&dma_heap_devt, 0, NUM_HEAP_MINORS, DEVNAME);
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if (ret)
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return ret;
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dma_heap_class = class_create(THIS_MODULE, DEVNAME);
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if (IS_ERR(dma_heap_class)) {
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unregister_chrdev_region(dma_heap_devt, NUM_HEAP_MINORS);
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return PTR_ERR(dma_heap_class);
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}
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dma_heap_class->devnode = dma_heap_devnode;
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return 0;
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}
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subsys_initcall(dma_heap_init);
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