From: "Andrew F. Davis" afd@ti.com
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: Xu YiPing xuyiping@hisilicon.com Cc: "Chenfeng (puck)" puck.chen@hisilicon.com Cc: butao butao@hisilicon.com Cc: "Xiaqing (A)" saberlily.xia@hisilicon.com Cc: Yudongbin yudongbin@hisilicon.com Cc: Christoph Hellwig hch@infradead.org Cc: Chenbo Feng fengc@google.com Cc: Alistair Strachan astrachan@google.com Cc: dri-devel@lists.freedesktop.org Signed-off-by: Andrew F. Davis afd@ti.com Signed-off-by: John Stultz john.stultz@linaro.org --- v2: * Folded down fixes I had previously shared in implementing heaps * Make flags a u64 (Suggested by Laura) * Add PAGE_ALIGN() fix to the core alloc funciton * IOCTL fixups suggested by Brian * Added fixes suggested by Benjamin * Removed core stats mgmt, as that should be implemented by per-heap code * Changed alloc to return a dma-buf fd, rather then a buffer (as it simplifies error handling) v3: * Removed scare-quotes in MAINTAINERS email address * Get rid of .release function as it didn't do anything (from Christoph) * Renamed filp to file (suggested by Christoph) * Split out ioctl handling to separate function (suggested by Christoph) * Add comment documenting PAGE_ALIGN usage (suggested by Brian) * Switch from idr to Xarray (suggested by Brian) * Fixup cdev creation (suggested by Brian) * Avoid EXPORT_SYMBOL until we finalize modules (suggested by Brian) * Make struct dma_heap internal only (folded in from Andrew) * Small cleanups suggested by GregKH * Provide class->devnode callback to get consistent /dev/ subdirectory naming (Suggested by Bjorn) --- MAINTAINERS | 18 ++++ drivers/dma-buf/Kconfig | 8 ++ drivers/dma-buf/Makefile | 1 + drivers/dma-buf/dma-heap.c | 234 ++++++++++++++++++++++++++++++++++++++++++ include/linux/dma-heap.h | 70 +++++++++++++ include/uapi/linux/dma-heap.h | 52 ++++++++++ 6 files changed, 383 insertions(+) create mode 100644 drivers/dma-buf/dma-heap.c create mode 100644 include/linux/dma-heap.h create mode 100644 include/uapi/linux/dma-heap.h
diff --git a/MAINTAINERS b/MAINTAINERS index c0057dd..cd9c495 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -4719,6 +4719,24 @@ 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 diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig index 2e5a0fa..09c61db 100644 --- a/drivers/dma-buf/Kconfig +++ b/drivers/dma-buf/Kconfig @@ -39,4 +39,12 @@ config UDMABUF A driver to let userspace turn memfd regions into dma-bufs. Qemu can use this to create host dmabufs for guest framebuffers.
+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 allows userspace to allocate dma-bufs that can be shared between + drivers. + endmenu diff --git a/drivers/dma-buf/Makefile b/drivers/dma-buf/Makefile index 0913a6c..b0332f1 100644 --- a/drivers/dma-buf/Makefile +++ b/drivers/dma-buf/Makefile @@ -1,4 +1,5 @@ obj-y := dma-buf.o dma-fence.o dma-fence-array.o reservation.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 diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c new file mode 100644 index 0000000..b52959e --- /dev/null +++ b/drivers/dma-buf/dma-heap.c @@ -0,0 +1,234 @@ +// 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/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; + struct dma_heap_ops *ops; + void *priv; + unsigned int minor; + dev_t heap_devt; + struct cdev heap_cdev; +}; + +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 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, 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 || + heap_allocation.reserved2) { + pr_warn_once("dma_heap: ioctl data not valid\n"); + return -EINVAL; + } + + if (heap_allocation.flags & ~DMA_HEAP_VALID_FLAGS) { + pr_warn_once("dma_heap: flags has invalid or unsupported flags set\n"); + return -EINVAL; + } + + fd = dma_heap_buffer_alloc(heap, heap_allocation.len, + heap_allocation.flags); + if (fd < 0) + return fd; + + heap_allocation.fd = fd; + + if (copy_to_user((void __user *)arg, &heap_allocation, + sizeof(heap_allocation))) + 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, +}; + +/** + * dma_heap_get_data() - 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_data(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; + 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); + } + + 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"); + return ERR_PTR(ret); + } + + /* 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"); + return ERR_PTR(ret); + } + + /* + * TODO: Need to filter "name" to make + * sure we don't add something crazy + */ + 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"); + cdev_del(&heap->heap_cdev); + return (struct dma_heap *)dev_ret; + } + + return heap; +} + +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); diff --git a/include/linux/dma-heap.h b/include/linux/dma-heap.h new file mode 100644 index 0000000..d7bf624 --- /dev/null +++ b/include/linux/dma-heap.h @@ -0,0 +1,70 @@ +/* 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_buffer - metadata for a particular buffer + * @heap: back pointer to the heap the buffer came from + * @dmabuf: backing dma-buf for this buffer + * @size: size of the buffer + * @flags: buffer specific flags + */ +struct dma_heap_buffer { + struct dma_heap *heap; + struct dma_buf *dmabuf; + size_t size; + unsigned long flags; +}; + +/** + * 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 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; + struct dma_heap_ops *ops; + void *priv; +}; + +/** + * dma_heap_get_data() - 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_data(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 */ diff --git a/include/uapi/linux/dma-heap.h b/include/uapi/linux/dma-heap.h new file mode 100644 index 0000000..0869811 --- /dev/null +++ b/include/uapi/linux/dma-heap.h @@ -0,0 +1,52 @@ +/* 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 + * + */ + +/* Currently no flags */ +#define DMA_HEAP_VALID_FLAGS (0) + +/** + * struct dma_heap_allocation_data - metadata passed from userspace for + * allocations + * @len: size of the allocation + * @flags: flags passed to pool + * @fd: will be populated with a fd which provdes the + * handle to the allocated dma-buf + * + * Provided by userspace as an argument to the ioctl + */ +struct dma_heap_allocation_data { + __u64 len; + __u64 flags; + __u32 fd; + __u32 reserved0; + __u32 reserved1; + __u32 reserved2; +}; + +#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 */