summaryrefslogtreecommitdiff
path: root/drivers/dma-buf/dma-heap.c
diff options
context:
space:
mode:
authorAndrew F. Davis <afd@ti.com>2019-10-21 22:03:06 +0300
committerSumit Semwal <sumit.semwal@linaro.org>2019-10-25 14:31:45 +0300
commita69b0e855d3fd278ff6f09a23e1edf929538e304 (patch)
tree57cc1eccaaba265d252784b18c27b106c85f94d1 /drivers/dma-buf/dma-heap.c
parentea7d8c675ea5b8db9441b50d1b7939228c26e622 (diff)
downloadlinux-a69b0e855d3fd278ff6f09a23e1edf929538e304.tar.xz
dma-buf: Add dma-buf heaps framework
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
Diffstat (limited to 'drivers/dma-buf/dma-heap.c')
-rw-r--r--drivers/dma-buf/dma-heap.c269
1 files changed, 269 insertions, 0 deletions
diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c
new file mode 100644
index 000000000000..9a41b73e54b4
--- /dev/null
+++ b/drivers/dma-buf/dma-heap.c
@@ -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);