From 4c5a9a5db543b5fd998fbc3e15fd4a2d2a3971a9 Mon Sep 17 00:00:00 2001 From: "Andrew F. Davis" Date: Tue, 3 Dec 2019 17:26:37 +0000 Subject: [PATCH] dma-buf: Add dma-buf heaps framework Commit c02a81fba74fe3488ad6b08bfb5a1329005418f8 upstream. 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 Cc: Benjamin Gaignard Cc: Sumit Semwal Cc: Liam Mark Cc: Pratik Patel Cc: Brian Starkey Cc: Vincent Donnefort Cc: Sudipto Paul Cc: Andrew F. Davis Cc: Christoph Hellwig Cc: Chenbo Feng Cc: Alistair Strachan Cc: Hridya Valsaraju Cc: Sandeep Patil Cc: Hillf Danton Cc: Dave Airlie Cc: dri-devel@lists.freedesktop.org Reviewed-by: Brian Starkey Acked-by: Sandeep Patil Signed-off-by: Andrew F. Davis Signed-off-by: John Stultz Signed-off-by: Sumit Semwal Link: https://patchwork.freedesktop.org/patch/msgid/20191203172641.66642-2-john.stultz@linaro.org --- MAINTAINERS | 18 +++ drivers/dma-buf/Kconfig | 9 ++ drivers/dma-buf/Makefile | 1 + drivers/dma-buf/dma-heap.c | 297 ++++++++++++++++++++++++++++++++++ include/linux/dma-heap.h | 59 +++++++ include/uapi/linux/dma-heap.h | 53 ++++++ 6 files changed, 437 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 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -4962,6 +4962,24 @@ 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 +R: Andrew F. Davis +R: Benjamin Gaignard +R: Liam Mark +R: Laura Abbott +R: Brian Starkey +R: John Stultz +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 L: dmaengine@vger.kernel.org --- a/drivers/dma-buf/Kconfig +++ b/drivers/dma-buf/Kconfig @@ -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 --- a/drivers/dma-buf/Makefile +++ b/drivers/dma-buf/Makefile @@ -3,6 +3,7 @@ obj-$(CONFIG_DMA_SHARED_BUFFER) := dma-s dma-buf-objs-y := dma-buf.o dma-fence.o dma-fence-array.o dma-fence-chain.o \ dma-resv.o seqno-fence.o +obj-$(CONFIG_DMABUF_HEAPS) += dma-heap.o dma-buf-objs-$(CONFIG_SYNC_FILE) += sync_file.o dma-buf-objs-$(CONFIG_SW_SYNC) += sw_sync.o sync_debug.o dma-buf-objs-$(CONFIG_UDMABUF) += udmabuf.o --- /dev/null +++ b/drivers/dma-buf/dma-heap.c @@ -0,0 +1,297 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Framework for userspace DMA-BUF allocations + * + * Copyright (C) 2011 Google, Inc. + * Copyright (C) 2019 Linaro Ltd. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#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 + * @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 { + const char *name; + const struct dma_heap_ops *ops; + void *priv; + 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, void *data) +{ + struct dma_heap_allocation_data *heap_allocation = data; + struct dma_heap *heap = file->private_data; + int fd; + + if (heap_allocation->fd) + return -EINVAL; + + if (heap_allocation->fd_flags & ~DMA_HEAP_VALID_FD_FLAGS) + return -EINVAL; + + if (heap_allocation->heap_flags & ~DMA_HEAP_VALID_HEAP_FLAGS) + 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; + + return 0; +} + +unsigned int dma_heap_ioctl_cmds[] = { + DMA_HEAP_IOC_ALLOC, +}; + +static long dma_heap_ioctl(struct file *file, unsigned int ucmd, + unsigned long arg) +{ + char stack_kdata[128]; + char *kdata = stack_kdata; + unsigned int kcmd; + unsigned int in_size, out_size, drv_size, ksize; + int nr = _IOC_NR(ucmd); + int ret = 0; + + if (nr >= ARRAY_SIZE(dma_heap_ioctl_cmds)) + return -EINVAL; + + /* Get the kernel ioctl cmd that matches */ + kcmd = dma_heap_ioctl_cmds[nr]; + + /* Figure out the delta between user cmd size and kernel cmd size */ + drv_size = _IOC_SIZE(kcmd); + out_size = _IOC_SIZE(ucmd); + in_size = out_size; + if ((ucmd & kcmd & IOC_IN) == 0) + in_size = 0; + if ((ucmd & kcmd & IOC_OUT) == 0) + out_size = 0; + ksize = max(max(in_size, out_size), drv_size); + + /* If necessary, allocate buffer for ioctl argument */ + if (ksize > sizeof(stack_kdata)) { + kdata = kmalloc(ksize, GFP_KERNEL); + if (!kdata) + return -ENOMEM; + } + + if (copy_from_user(kdata, (void __user *)arg, in_size) != 0) { + ret = -EFAULT; + goto err; + } + + /* zero out any difference between the kernel/user structure size */ + if (ksize > in_size) + memset(kdata + in_size, 0, ksize - in_size); + + switch (kcmd) { + case DMA_HEAP_IOC_ALLOC: + ret = dma_heap_ioctl_allocate(file, kdata); + break; + default: + return -ENOTTY; + } + + if (copy_to_user((void __user *)arg, kdata, out_size) != 0) + ret = -EFAULT; +err: + if (kdata != stack_kdata) + kfree(kdata); + 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; + unsigned int minor; + 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, &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), 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, 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); --- /dev/null +++ b/include/linux/dma-heap.h @@ -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 +#include + +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 */ --- /dev/null +++ b/include/uapi/linux/dma-heap.h @@ -0,0 +1,53 @@ +/* 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 +#include + +/** + * 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 provides 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; +}; + +#define DMA_HEAP_IOC_MAGIC 'H' + +/** + * DOC: DMA_HEAP_IOC_ALLOC - allocate memory from pool + * + * Takes a 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, 0x0,\ + struct dma_heap_allocation_data) + +#endif /* _UAPI_LINUX_DMABUF_POOL_H */