From: Daniel Vetter daniel.vetter@ffwll.ch
FIXME: Update kerneldoc for begin/end to make it clear that those are for mmap too.
Open: Do we need a special indication that the begin/end is from userspace mmap and not from kernel mmap?
There's also the question already about kernel internal users - vmap and kmap interfaces are much different ... We might need to add a mapping enum to the begin/end dma-buf functions.
v2 (Tiago): Fix header file type names (u64 -> __u64)
Signed-off-by: Daniel Vetter daniel.vetter@intel.com Signed-off-by: Tiago Vignatti tiago.vignatti@intel.com --- drivers/dma-buf/dma-buf.c | 47 ++++++++++++++++++++++++++++++++++++++++++++ include/uapi/linux/dma-buf.h | 39 ++++++++++++++++++++++++++++++++++++ 2 files changed, 86 insertions(+) create mode 100644 include/uapi/linux/dma-buf.h
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 155c146..4820d61 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -34,6 +34,8 @@ #include <linux/poll.h> #include <linux/reservation.h>
+#include <uapi/linux/dma-buf.h> + static inline int is_dma_buf_file(struct file *);
struct dma_buf_list { @@ -251,11 +253,56 @@ out: return events; }
+static long dma_buf_ioctl(struct file *file, + unsigned int cmd, unsigned long arg) +{ + struct dma_buf *dmabuf; + struct dma_buf_sync sync; + enum dma_data_direction direction; + + dmabuf = file->private_data; + + if (!is_dma_buf_file(file)) + return -EINVAL; + + switch (cmd) { + case DMA_BUF_IOCTL_SYNC: + if (copy_from_user(&sync, (void __user *) arg, sizeof(sync))) + return -EFAULT; + + if (sync.flags & DMA_BUF_SYNC_RW) + direction = DMA_BIDIRECTIONAL; + else if (sync.flags & DMA_BUF_SYNC_READ) + direction = DMA_FROM_DEVICE; + else if (sync.flags & DMA_BUF_SYNC_WRITE) + direction = DMA_TO_DEVICE; + else + return -EINVAL; + + if (sync.flags & ~DMA_BUF_SYNC_VALID_FLAGS_MASK) + return -EINVAL; + + /* FIXME: Check for overflows in start/length. */ + + if (sync.flags & DMA_BUF_SYNC_END) + dma_buf_end_cpu_access(dmabuf, sync.start, + sync.length, direction); + else + dma_buf_begin_cpu_access(dmabuf, sync.start, + sync.length, direction); + + return 0; + default: + return -ENOTTY; + } +} + static const struct file_operations dma_buf_fops = { .release = dma_buf_release, .mmap = dma_buf_mmap_internal, .llseek = dma_buf_llseek, .poll = dma_buf_poll, + .unlocked_ioctl = dma_buf_ioctl, };
/* diff --git a/include/uapi/linux/dma-buf.h b/include/uapi/linux/dma-buf.h new file mode 100644 index 0000000..e5327df --- /dev/null +++ b/include/uapi/linux/dma-buf.h @@ -0,0 +1,39 @@ +/* + * Framework for buffer objects that can be shared across devices/subsystems. + * + * Copyright(C) 2015 Intel Ltd + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published by + * the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program. If not, see http://www.gnu.org/licenses/. + */ + +#ifndef _DMA_BUF_UAPI_H_ +#define _DMA_BUF_UAPI_H_ + +struct dma_buf_sync { + __u64 flags; + __u64 start; + __u64 length; +}; + +#define DMA_BUF_SYNC_READ (1 << 0) +#define DMA_BUF_SYNC_WRITE (2 << 0) +#define DMA_BUF_SYNC_RW (3 << 0) +#define DMA_BUF_SYNC_START (0 << 2) +#define DMA_BUF_SYNC_END (1 << 2) +#define DMA_BUF_SYNC_VALID_FLAGS_MASK \ + (DMA_BUF_SYNC_RW | DMA_BUF_SYNC_END) + +#define DMA_BUF_BASE 'b' +#define DMA_BUF_IOCTL_SYNC _IOWR(DMA_BUF_BASE, 0, struct dma_buf_sync) + +#endif