This is a simple test module that can be used to allocate, export and delete DMA-BUF objects. It can be used to test DMA-BUF sharing in systems that lack a real second driver.
Signed-off-by: Thierry Reding treding@nvidia.com --- drivers/base/Kconfig | 4 + drivers/base/Makefile | 1 + drivers/base/dma-buf-test.c | 308 ++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 313 insertions(+) create mode 100644 drivers/base/dma-buf-test.c
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig index e373671652b0..bed2abb9491b 100644 --- a/drivers/base/Kconfig +++ b/drivers/base/Kconfig @@ -200,6 +200,10 @@ config DMA_SHARED_BUFFER APIs extension; the file's descriptor can then be passed on to other driver.
+config DMA_BUF_TEST + tristate "DMA-BUF test module" + depends on DMA_SHARED_BUFFER + config DMA_CMA bool "DMA Contiguous Memory Allocator" depends on HAVE_DMA_CONTIGUOUS && CMA diff --git a/drivers/base/Makefile b/drivers/base/Makefile index 94e8a80e87f8..cad983b6626f 100644 --- a/drivers/base/Makefile +++ b/drivers/base/Makefile @@ -25,3 +25,4 @@ obj-$(CONFIG_PINCTRL) += pinctrl.o
ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG
+obj-$(CONFIG_DMA_BUF_TEST) += dma-buf-test.o diff --git a/drivers/base/dma-buf-test.c b/drivers/base/dma-buf-test.c new file mode 100644 index 000000000000..f5498b74a09b --- /dev/null +++ b/drivers/base/dma-buf-test.c @@ -0,0 +1,308 @@ +#include <linux/dma-buf.h> +#include <linux/err.h> +#include <linux/fs.h> +#include <linux/miscdevice.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/uaccess.h> + +struct dmabuf_create { + __u32 flags; + __u32 size; +}; + +#define DMABUF_IOCTL_BASE 'D' +#define DMABUF_IOCTL_CREATE _IOWR(DMABUF_IOCTL_BASE, 0, struct dmabuf_create) +#define DMABUF_IOCTL_DELETE _IOWR(DMABUF_IOCTL_BASE, 1, int) +#define DMABUF_IOCTL_EXPORT _IOWR(DMABUF_IOCTL_BASE, 2, int) + +struct dmabuf_file { + struct dma_buf *buf; + dma_addr_t phys; + size_t size; + void *virt; +}; + +static int dmabuf_attach(struct dma_buf *buf, struct device *dev, + struct dma_buf_attachment *attach) +{ + return 0; +} + +static void dmabuf_detach(struct dma_buf *buf, + struct dma_buf_attachment *attach) +{ +} + +static struct sg_table *dmabuf_map_dma_buf(struct dma_buf_attachment *attach, + enum dma_data_direction dir) +{ + struct dmabuf_file *priv = attach->dmabuf->priv; + struct sg_table *sgt; + + sgt = kmalloc(sizeof(*sgt), GFP_KERNEL); + if (!sgt) + return NULL; + + if (sg_alloc_table(sgt, 1, GFP_KERNEL)) { + kfree(sgt); + return NULL; + } + + sg_dma_address(sgt->sgl) = priv->phys; + sg_dma_len(sgt->sgl) = priv->size; + + return sgt; +} + +static void dmabuf_unmap_dma_buf(struct dma_buf_attachment *attach, + struct sg_table *sgt, + enum dma_data_direction dir) +{ + sg_free_table(sgt); + kfree(sgt); +} + +static void dmabuf_release(struct dma_buf *buf) +{ +} + +static int dmabuf_begin_cpu_access(struct dma_buf *buf, size_t size, + size_t length, + enum dma_data_direction direction) +{ + return 0; +} + +static void dmabuf_end_cpu_access(struct dma_buf *buf, size_t size, + size_t length, + enum dma_data_direction direction) +{ +} + +static void *dmabuf_kmap_atomic(struct dma_buf *buf, unsigned long page) +{ + return NULL; +} + +static void dmabuf_kunmap_atomic(struct dma_buf *buf, unsigned long page, + void *vaddr) +{ +} + +static void *dmabuf_kmap(struct dma_buf *buf, unsigned long page) +{ + return NULL; +} + +static void dmabuf_kunmap(struct dma_buf *buf, unsigned long page, void *vaddr) +{ +} + +static void dmabuf_vm_open(struct vm_area_struct *vma) +{ +} + +static void dmabuf_vm_close(struct vm_area_struct *vma) +{ +} + +static int dmabuf_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf) +{ + return 0; +} + +static const struct vm_operations_struct dmabuf_vm_ops = { + .open = dmabuf_vm_open, + .close = dmabuf_vm_close, + .fault = dmabuf_vm_fault, +}; + +static int dmabuf_mmap(struct dma_buf *buf, struct vm_area_struct *vma) +{ + pgprot_t prot = vm_get_page_prot(vma->vm_flags); + struct dmabuf_file *priv = buf->priv; + + vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; + vma->vm_ops = &dmabuf_vm_ops; + vma->vm_private_data = priv; + vma->vm_page_prot = pgprot_writecombine(prot); + + return remap_pfn_range(vma, vma->vm_start, priv->phys >> PAGE_SHIFT, + vma->vm_end - vma->vm_start, vma->vm_page_prot); +} + +static void *dmabuf_vmap(struct dma_buf *buf) +{ + return NULL; +} + +static void dmabuf_vunmap(struct dma_buf *buf, void *vaddr) +{ +} + +static const struct dma_buf_ops dmabuf_ops = { + .attach = dmabuf_attach, + .detach = dmabuf_detach, + .map_dma_buf = dmabuf_map_dma_buf, + .unmap_dma_buf = dmabuf_unmap_dma_buf, + .release = dmabuf_release, + .begin_cpu_access = dmabuf_begin_cpu_access, + .end_cpu_access = dmabuf_end_cpu_access, + .kmap_atomic = dmabuf_kmap_atomic, + .kunmap_atomic = dmabuf_kunmap_atomic, + .kmap = dmabuf_kmap, + .kunmap = dmabuf_kunmap, + .mmap = dmabuf_mmap, + .vmap = dmabuf_vmap, + .vunmap = dmabuf_vunmap, +}; + +static int dmabuf_file_open(struct inode *inode, struct file *file) +{ + struct dmabuf_file *priv; + int ret = 0; + + priv = kzalloc(sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + file->private_data = priv; + + return ret; +} + +static int dmabuf_file_release(struct inode *inode, struct file *file) +{ + struct dmabuf_file *priv = file->private_data; + int ret = 0; + + if (priv->virt) + dma_free_writecombine(NULL, priv->size, priv->virt, priv->phys); + + if (priv->buf) + dma_buf_put(priv->buf); + + kfree(priv); + + return ret; +} + +static int dmabuf_ioctl_create(struct dmabuf_file *priv, const void __user *data) +{ + struct dmabuf_create args; + int ret = 0; + + if (priv->buf || priv->virt) + return -EBUSY; + + if (copy_from_user(&args, data, sizeof(args))) + return -EFAULT; + + priv->virt = dma_alloc_writecombine(NULL, args.size, &priv->phys, + GFP_KERNEL | __GFP_NOWARN); + if (!priv->virt) + return -ENOMEM; + + priv->buf = dma_buf_export(priv, &dmabuf_ops, args.size, args.flags); + if (!priv->buf) { + ret = -ENOMEM; + goto free; + } + + if (IS_ERR(priv->buf)) { + ret = PTR_ERR(priv->buf); + goto free; + } + + priv->size = args.size; + + return 0; + +free: + dma_free_writecombine(NULL, priv->size, priv->virt, priv->phys); + priv->virt = NULL; + return ret; +} + +static int dmabuf_ioctl_delete(struct dmabuf_file *priv, unsigned long flags) +{ + dma_free_writecombine(NULL, priv->size, priv->virt, priv->phys); + priv->virt = NULL; + priv->phys = 0; + priv->size = 0; + + dma_buf_put(priv->buf); + priv->buf = NULL; + + return 0; +} + +static int dmabuf_ioctl_export(struct dmabuf_file *priv, unsigned long flags) +{ + int err; + + get_dma_buf(priv->buf); + + err = dma_buf_fd(priv->buf, flags); + if (err < 0) + dma_buf_put(priv->buf); + + return err; +} + +static long dmabuf_file_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + struct dmabuf_file *priv = file->private_data; + long ret = 0; + + switch (cmd) { + case DMABUF_IOCTL_CREATE: + ret = dmabuf_ioctl_create(priv, (const void __user *)arg); + break; + + case DMABUF_IOCTL_DELETE: + ret = dmabuf_ioctl_delete(priv, arg); + break; + + case DMABUF_IOCTL_EXPORT: + ret = dmabuf_ioctl_export(priv, arg); + break; + + default: + ret = -ENOTTY; + break; + } + + return ret; +} + +static const struct file_operations dmabuf_fops = { + .owner = THIS_MODULE, + .open = dmabuf_file_open, + .release = dmabuf_file_release, + .unlocked_ioctl = dmabuf_file_ioctl, +}; + +static struct miscdevice dmabuf_device = { + .minor = 128, + .name = "dmabuf", + .fops = &dmabuf_fops, +}; + +static int __init dmabuf_init(void) +{ + return misc_register(&dmabuf_device); +} +module_init(dmabuf_init); + +static void __exit dmabuf_exit(void) +{ + misc_deregister(&dmabuf_device); +} +module_exit(dmabuf_exit); + +MODULE_AUTHOR("Thierry Reding treding@nvidia.com"); +MODULE_DESCRIPTION("DMA-BUF test driver"); +MODULE_LICENSE("GPL v2");