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dma-buf: Add dma-buf heaps framework

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This framework allows a unified userspace interface for dma-buf
exporters, allowing userland to allocate specific types of memory
for use in dma-buf sharing.

Each heap is given its own device node, which a user can allocate
a dma-buf fd from using the DMA_HEAP_IOC_ALLOC.

This code is an evoluiton of the Android ION implementation,
and a big thanks is due to its authors/maintainers over time
for their effort:
  Rebecca Schultz Zavin, Colin Cross, Benjamin Gaignard,
  Laura Abbott, and many other contributors!

Cc: Laura Abbott <labbott@redhat.com>
Cc: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Liam Mark <lmark@codeaurora.org>
Cc: Pratik Patel <pratikp@codeaurora.org>
Cc: Brian Starkey <Brian.Starkey@arm.com>
Cc: Vincent Donnefort <Vincent.Donnefort@arm.com>
Cc: Sudipto Paul <Sudipto.Paul@arm.com>
Cc: Andrew F. Davis <afd@ti.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Chenbo Feng <fengc@google.com>
Cc: Alistair Strachan <astrachan@google.com>
Cc: Hridya Valsaraju <hridya@google.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Reviewed-by: Brian Starkey <brian.starkey@arm.com>
Acked-by: Laura Abbott <labbott@redhat.com>
Tested-by: Ayan Kumar Halder <ayan.halder@arm.com>
Signed-off-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20191021190310.85221-2-john.stultz@linaro.org
This commit is contained in:
Andrew F. Davis 2019-10-21 19:03:06 +00:00 committed by Sumit Semwal
parent ea7d8c675e
commit a69b0e855d
6 changed files with 411 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

18
MAINTAINERS
View file

@ -4942,6 +4942,24 @@ F: include/linux/*fence.h
F: Documentation/driver-api/dma-buf.rst
T: git git://anongit.freedesktop.org/drm/drm-misc
DMA-BUF HEAPS FRAMEWORK
M: Sumit Semwal <sumit.semwal@linaro.org>
R: Andrew F. Davis <afd@ti.com>
R: Benjamin Gaignard <benjamin.gaignard@linaro.org>
R: Liam Mark <lmark@codeaurora.org>
R: Laura Abbott <labbott@redhat.com>
R: Brian Starkey <Brian.Starkey@arm.com>
R: John Stultz <john.stultz@linaro.org>
S: Maintained
L: linux-media@vger.kernel.org
L: dri-devel@lists.freedesktop.org
L: linaro-mm-sig@lists.linaro.org (moderated for non-subscribers)
F: include/uapi/linux/dma-heap.h
F: include/linux/dma-heap.h
F: drivers/dma-buf/dma-heap.c
F: drivers/dma-buf/heaps/*
T: git git://anongit.freedesktop.org/drm/drm-misc
DMA GENERIC OFFLOAD ENGINE SUBSYSTEM
M: Vinod Koul <vkoul@kernel.org>
L: dmaengine@vger.kernel.org

9
drivers/dma-buf/Kconfig
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@ -44,4 +44,13 @@ config DMABUF_SELFTESTS
default n
depends on DMA_SHARED_BUFFER
menuconfig DMABUF_HEAPS
bool "DMA-BUF Userland Memory Heaps"
select DMA_SHARED_BUFFER
help
Choose this option to enable the DMA-BUF userland memory heaps.
This options creates per heap chardevs in /dev/dma_heap/ which
allows userspace to allocate dma-bufs that can be shared
between drivers.
endmenu

1
drivers/dma-buf/Makefile
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@ -1,6 +1,7 @@
# SPDX-License-Identifier: GPL-2.0-only
obj-y := dma-buf.o dma-fence.o dma-fence-array.o dma-fence-chain.o \
dma-resv.o seqno-fence.o
obj-$(CONFIG_DMABUF_HEAPS) += dma-heap.o
obj-$(CONFIG_SYNC_FILE) += sync_file.o
obj-$(CONFIG_SW_SYNC) += sw_sync.o sync_debug.o
obj-$(CONFIG_UDMABUF) += udmabuf.o

269
drivers/dma-buf/dma-heap.c Normal file
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@ -0,0 +1,269 @@
// 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/uaccess.h>
#include <linux/syscalls.h>
#include <linux/dma-heap.h>
#include <uapi/linux/dma-heap.h>
#define DEVNAME "dma_heap"
#define NUM_HEAP_MINORS 128
/**
* struct dma_heap - represents a dmabuf heap in the system
* @name: used for debugging/device-node name
* @ops: ops struct for this heap
* @minor minor number of this heap device
* @heap_devt heap device node
* @heap_cdev heap char device
*
* Represents a heap of memory from which buffers can be made.
*/
struct dma_heap {
const char *name;
const struct dma_heap_ops *ops;
void *priv;
unsigned int minor;
dev_t heap_devt;
struct list_head list;
struct cdev heap_cdev;
};
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,
unsigned int fd_flags,
unsigned int heap_flags)
{
/*
* Allocations from all heaps have to begin
* and end on page boundaries.
*/
len = PAGE_ALIGN(len);
if (!len)
return -EINVAL;
return heap->ops->allocate(heap, len, fd_flags, heap_flags);
}
static int dma_heap_open(struct inode *inode, struct file *file)
{
struct dma_heap *heap;
heap = xa_load(&dma_heap_minors, iminor(inode));
if (!heap) {
pr_err("dma_heap: minor %d unknown.\n", iminor(inode));
return -ENODEV;
}
/* instance data as context */
file->private_data = heap;
nonseekable_open(inode, file);
return 0;
}
static long dma_heap_ioctl_allocate(struct file *file, unsigned long arg)
{
struct dma_heap_allocation_data heap_allocation;
struct dma_heap *heap = file->private_data;
int fd;
if (copy_from_user(&heap_allocation, (void __user *)arg,
sizeof(heap_allocation)))
return -EFAULT;
if (heap_allocation.fd ||
heap_allocation.reserved0 ||
heap_allocation.reserved1) {
pr_warn_once("dma_heap: ioctl data not valid\n");
return -EINVAL;
}
if (heap_allocation.fd_flags & ~DMA_HEAP_VALID_FD_FLAGS) {
pr_warn_once("dma_heap: fd_flags has invalid or unsupported flags set\n");
return -EINVAL;
}
if (heap_allocation.heap_flags & ~DMA_HEAP_VALID_HEAP_FLAGS) {
pr_warn_once("dma_heap: heap flags has invalid or unsupported flags set\n");
return -EINVAL;
}
fd = dma_heap_buffer_alloc(heap, heap_allocation.len,
heap_allocation.fd_flags,
heap_allocation.heap_flags);
if (fd < 0)
return fd;
heap_allocation.fd = fd;
if (copy_to_user((void __user *)arg, &heap_allocation,
sizeof(heap_allocation))) {
ksys_close(fd);
return -EFAULT;
}
return 0;
}
static long dma_heap_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
int ret = 0;
switch (cmd) {
case DMA_HEAP_IOC_ALLOC:
ret = dma_heap_ioctl_allocate(file, arg);
break;
default:
return -ENOTTY;
}
return ret;
}
static const struct file_operations dma_heap_fops = {
.owner = THIS_MODULE,
.open = dma_heap_open,
.unlocked_ioctl = dma_heap_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = dma_heap_ioctl,
#endif
};
/**
* 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)
{
return heap->priv;
}
struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info)
{
struct dma_heap *heap, *h, *err_ret;
struct device *dev_ret;
int ret;
if (!exp_info->name || !strcmp(exp_info->name, "")) {
pr_err("dma_heap: Cannot add heap without a name\n");
return ERR_PTR(-EINVAL);
}
if (!exp_info->ops || !exp_info->ops->allocate) {
pr_err("dma_heap: Cannot add heap with invalid ops struct\n");
return ERR_PTR(-EINVAL);
}
/* check the name is unique */
mutex_lock(&heap_list_lock);
list_for_each_entry(h, &heap_list, list) {
if (!strcmp(h->name, exp_info->name)) {
mutex_unlock(&heap_list_lock);
pr_err("dma_heap: Already registered heap named %s\n",
exp_info->name);
return ERR_PTR(-EINVAL);
}
}
mutex_unlock(&heap_list_lock);
heap = kzalloc(sizeof(*heap), GFP_KERNEL);
if (!heap)
return ERR_PTR(-ENOMEM);
heap->name = exp_info->name;
heap->ops = exp_info->ops;
heap->priv = exp_info->priv;
/* Find unused minor number */
ret = xa_alloc(&dma_heap_minors, &heap->minor, heap,
XA_LIMIT(0, NUM_HEAP_MINORS - 1), GFP_KERNEL);
if (ret < 0) {
pr_err("dma_heap: Unable to get minor number for heap\n");
err_ret = ERR_PTR(ret);
goto err0;
}
/* Create device */
heap->heap_devt = MKDEV(MAJOR(dma_heap_devt), heap->minor);
cdev_init(&heap->heap_cdev, &dma_heap_fops);
ret = cdev_add(&heap->heap_cdev, heap->heap_devt, 1);
if (ret < 0) {
pr_err("dma_heap: Unable to add char device\n");
err_ret = ERR_PTR(ret);
goto err1;
}
dev_ret = device_create(dma_heap_class,
NULL,
heap->heap_devt,
NULL,
heap->name);
if (IS_ERR(dev_ret)) {
pr_err("dma_heap: Unable to create device\n");
err_ret = ERR_CAST(dev_ret);
goto err2;
}
/* Add heap to the list */
mutex_lock(&heap_list_lock);
list_add(&heap->list, &heap_list);
mutex_unlock(&heap_list_lock);
return heap;
err2:
cdev_del(&heap->heap_cdev);
err1:
xa_erase(&dma_heap_minors, heap->minor);
err0:
kfree(heap);
return err_ret;
}
static char *dma_heap_devnode(struct device *dev, umode_t *mode)
{
return kasprintf(GFP_KERNEL, "dma_heap/%s", dev_name(dev));
}
static int dma_heap_init(void)
{
int ret;
ret = alloc_chrdev_region(&dma_heap_devt, 0, NUM_HEAP_MINORS, DEVNAME);
if (ret)
return ret;
dma_heap_class = class_create(THIS_MODULE, DEVNAME);
if (IS_ERR(dma_heap_class)) {
unregister_chrdev_region(dma_heap_devt, NUM_HEAP_MINORS);
return PTR_ERR(dma_heap_class);
}
dma_heap_class->devnode = dma_heap_devnode;
return 0;
}
subsys_initcall(dma_heap_init);

59
include/linux/dma-heap.h Normal file
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@ -0,0 +1,59 @@
/* SPDX-License-Identifier: GPL-2.0 */
/*
* DMABUF Heaps Allocation Infrastructure
*
* Copyright (C) 2011 Google, Inc.
* Copyright (C) 2019 Linaro Ltd.
*/
#ifndef _DMA_HEAPS_H
#define _DMA_HEAPS_H
#include <linux/cdev.h>
#include <linux/types.h>
struct dma_heap;
/**
* struct dma_heap_ops - ops to operate on a given heap
* @allocate: allocate dmabuf and return fd
*
* allocate returns dmabuf fd on success, -errno on error.
*/
struct dma_heap_ops {
int (*allocate)(struct dma_heap *heap,
unsigned long len,
unsigned long fd_flags,
unsigned long heap_flags);
};
/**
* struct dma_heap_export_info - information needed to export a new dmabuf heap
* @name: used for debugging/device-node name
* @ops: ops struct for this heap
* @priv: heap exporter private data
*
* Information needed to export a new dmabuf heap.
*/
struct dma_heap_export_info {
const char *name;
const struct dma_heap_ops *ops;
void *priv;
};
/**
* dma_heap_get_drvdata() - get per-heap driver data
* @heap: DMA-Heap to retrieve private data for
*
* Returns:
* The per-heap data for the heap.
*/
void *dma_heap_get_drvdata(struct dma_heap *heap);
/**
* dma_heap_add - adds a heap to dmabuf heaps
* @exp_info: information needed to register this heap
*/
struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info);
#endif /* _DMA_HEAPS_H */

55
include/uapi/linux/dma-heap.h Normal file
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@ -0,0 +1,55 @@
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
/*
* DMABUF Heaps Userspace API
*
* Copyright (C) 2011 Google, Inc.
* Copyright (C) 2019 Linaro Ltd.
*/
#ifndef _UAPI_LINUX_DMABUF_POOL_H
#define _UAPI_LINUX_DMABUF_POOL_H
#include <linux/ioctl.h>
#include <linux/types.h>
/**
* DOC: DMABUF Heaps Userspace API
*/
/* Valid FD_FLAGS are O_CLOEXEC, O_RDONLY, O_WRONLY, O_RDWR */
#define DMA_HEAP_VALID_FD_FLAGS (O_CLOEXEC | O_ACCMODE)
/* Currently no heap flags */
#define DMA_HEAP_VALID_HEAP_FLAGS (0)
/**
* struct dma_heap_allocation_data - metadata passed from userspace for
* allocations
* @len: size of the allocation
* @fd: will be populated with a fd which provdes the
* handle to the allocated dma-buf
* @fd_flags: file descriptor flags used when allocating
* @heap_flags: flags passed to heap
*
* Provided by userspace as an argument to the ioctl
*/
struct dma_heap_allocation_data {
__u64 len;
__u32 fd;
__u32 fd_flags;
__u64 heap_flags;
__u32 reserved0;
__u32 reserved1;
};
#define DMA_HEAP_IOC_MAGIC 'H'
/**
* DOC: DMA_HEAP_IOC_ALLOC - allocate memory from pool
*
* Takes an dma_heap_allocation_data struct and returns it with the fd field
* populated with the dmabuf handle of the allocation.
*/
#define DMA_HEAP_IOC_ALLOC _IOWR(DMA_HEAP_IOC_MAGIC, 0, \
struct dma_heap_allocation_data)
#endif /* _UAPI_LINUX_DMABUF_POOL_H */