--- /dev/null
+/*
+ * Framework for buffer objects that can be shared across devices/subsystems.
+ *
+ * Copyright(C) 2011 Linaro Limited. All rights reserved.
+ * Author: Sumit Semwal <sumit.semwal@ti.com>
+ *
+ * Many thanks to linaro-mm-sig list, and specially
+ * Arnd Bergmann <arnd@arndb.de>, Rob Clark <rob@ti.com> and
+ * Daniel Vetter <daniel@ffwll.ch> for their support in creation and
+ * refining of this idea.
+ *
+ * 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/>.
+ */
+
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/dma-buf.h>
+#include <linux/anon_inodes.h>
+#include <linux/export.h>
+
+static inline int is_dma_buf_file(struct file *);
+
+static int dma_buf_release(struct inode *inode, struct file *file)
+{
+ struct dma_buf *dmabuf;
+
+ if (!is_dma_buf_file(file))
+ return -EINVAL;
+
+ dmabuf = file->private_data;
+
+ dmabuf->ops->release(dmabuf);
+ kfree(dmabuf);
+ return 0;
+}
+
+static const struct file_operations dma_buf_fops = {
+ .release = dma_buf_release,
+};
+
+/*
+ * is_dma_buf_file - Check if struct file* is associated with dma_buf
+ */
+static inline int is_dma_buf_file(struct file *file)
+{
+ return file->f_op == &dma_buf_fops;
+}
+
+/**
+ * dma_buf_export - Creates a new dma_buf, and associates an anon file
+ * with this buffer, so it can be exported.
+ * Also connect the allocator specific data and ops to the buffer.
+ *
+ * @priv: [in] Attach private data of allocator to this buffer
+ * @ops: [in] Attach allocator-defined dma buf ops to the new buffer.
+ * @size: [in] Size of the buffer
+ * @flags: [in] mode flags for the file.
+ *
+ * Returns, on success, a newly created dma_buf object, which wraps the
+ * supplied private data and operations for dma_buf_ops. On either missing
+ * ops, or error in allocating struct dma_buf, will return negative error.
+ *
+ */
+struct dma_buf *dma_buf_export(void *priv, struct dma_buf_ops *ops,
+ size_t size, int flags)
+{
+ struct dma_buf *dmabuf;
+ struct file *file;
+
+ if (WARN_ON(!priv || !ops
+ || !ops->map_dma_buf
+ || !ops->unmap_dma_buf
+ || !ops->release)) {
+ return ERR_PTR(-EINVAL);
+ }
+
+ dmabuf = kzalloc(sizeof(struct dma_buf), GFP_KERNEL);
+ if (dmabuf == NULL)
+ return ERR_PTR(-ENOMEM);
+
+ dmabuf->priv = priv;
+ dmabuf->ops = ops;
+ dmabuf->size = size;
+
+ file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf, flags);
+
+ dmabuf->file = file;
+
+ mutex_init(&dmabuf->lock);
+ INIT_LIST_HEAD(&dmabuf->attachments);
+
+ return dmabuf;
+}
+EXPORT_SYMBOL_GPL(dma_buf_export);
+
+
+/**
+ * dma_buf_fd - returns a file descriptor for the given dma_buf
+ * @dmabuf: [in] pointer to dma_buf for which fd is required.
+ *
+ * On success, returns an associated 'fd'. Else, returns error.
+ */
+int dma_buf_fd(struct dma_buf *dmabuf)
+{
+ int error, fd;
+
+ if (!dmabuf || !dmabuf->file)
+ return -EINVAL;
+
+ error = get_unused_fd();
+ if (error < 0)
+ return error;
+ fd = error;
+
+ fd_install(fd, dmabuf->file);
+
+ return fd;
+}
+EXPORT_SYMBOL_GPL(dma_buf_fd);
+
+/**
+ * dma_buf_get - returns the dma_buf structure related to an fd
+ * @fd: [in] fd associated with the dma_buf to be returned
+ *
+ * On success, returns the dma_buf structure associated with an fd; uses
+ * file's refcounting done by fget to increase refcount. returns ERR_PTR
+ * otherwise.
+ */
+struct dma_buf *dma_buf_get(int fd)
+{
+ struct file *file;
+
+ file = fget(fd);
+
+ if (!file)
+ return ERR_PTR(-EBADF);
+
+ if (!is_dma_buf_file(file)) {
+ fput(file);
+ return ERR_PTR(-EINVAL);
+ }
+
+ return file->private_data;
+}
+EXPORT_SYMBOL_GPL(dma_buf_get);
+
+/**
+ * dma_buf_put - decreases refcount of the buffer
+ * @dmabuf: [in] buffer to reduce refcount of
+ *
+ * Uses file's refcounting done implicitly by fput()
+ */
+void dma_buf_put(struct dma_buf *dmabuf)
+{
+ if (WARN_ON(!dmabuf || !dmabuf->file))
+ return;
+
+ fput(dmabuf->file);
+}
+EXPORT_SYMBOL_GPL(dma_buf_put);
+
+/**
+ * dma_buf_attach - Add the device to dma_buf's attachments list; optionally,
+ * calls attach() of dma_buf_ops to allow device-specific attach functionality
+ * @dmabuf: [in] buffer to attach device to.
+ * @dev: [in] device to be attached.
+ *
+ * Returns struct dma_buf_attachment * for this attachment; may return negative
+ * error codes.
+ *
+ */
+struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
+ struct device *dev)
+{
+ struct dma_buf_attachment *attach;
+ int ret;
+
+ if (WARN_ON(!dmabuf || !dev || !dmabuf->ops))
+ return ERR_PTR(-EINVAL);
+
+ attach = kzalloc(sizeof(struct dma_buf_attachment), GFP_KERNEL);
+ if (attach == NULL)
+ goto err_alloc;
+
+ mutex_lock(&dmabuf->lock);
+
+ attach->dev = dev;
+ attach->dmabuf = dmabuf;
+ if (dmabuf->ops->attach) {
+ ret = dmabuf->ops->attach(dmabuf, dev, attach);
+ if (ret)
+ goto err_attach;
+ }
+ list_add(&attach->node, &dmabuf->attachments);
+
+ mutex_unlock(&dmabuf->lock);
+ return attach;
+
+err_alloc:
+ return ERR_PTR(-ENOMEM);
+err_attach:
+ kfree(attach);
+ mutex_unlock(&dmabuf->lock);
+ return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(dma_buf_attach);
+
+/**
+ * dma_buf_detach - Remove the given attachment from dmabuf's attachments list;
+ * optionally calls detach() of dma_buf_ops for device-specific detach
+ * @dmabuf: [in] buffer to detach from.
+ * @attach: [in] attachment to be detached; is free'd after this call.
+ *
+ */
+void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
+{
+ if (WARN_ON(!dmabuf || !attach || !dmabuf->ops))
+ return;
+
+ mutex_lock(&dmabuf->lock);
+ list_del(&attach->node);
+ if (dmabuf->ops->detach)
+ dmabuf->ops->detach(dmabuf, attach);
+
+ mutex_unlock(&dmabuf->lock);
+ kfree(attach);
+}
+EXPORT_SYMBOL_GPL(dma_buf_detach);
+
+/**
+ * dma_buf_map_attachment - Returns the scatterlist table of the attachment;
+ * mapped into _device_ address space. Is a wrapper for map_dma_buf() of the
+ * dma_buf_ops.
+ * @attach: [in] attachment whose scatterlist is to be returned
+ * @direction: [in] direction of DMA transfer
+ *
+ * Returns sg_table containing the scatterlist to be returned; may return NULL
+ * or ERR_PTR.
+ *
+ */
+struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
+ enum dma_data_direction direction)
+{
+ struct sg_table *sg_table = ERR_PTR(-EINVAL);
+
+ might_sleep();
+
+ if (WARN_ON(!attach || !attach->dmabuf || !attach->dmabuf->ops))
+ return ERR_PTR(-EINVAL);
+
+ mutex_lock(&attach->dmabuf->lock);
+ if (attach->dmabuf->ops->map_dma_buf)
+ sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction);
+ mutex_unlock(&attach->dmabuf->lock);
+
+ return sg_table;
+}
+EXPORT_SYMBOL_GPL(dma_buf_map_attachment);
+
+/**
+ * dma_buf_unmap_attachment - unmaps and decreases usecount of the buffer;might
+ * deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of
+ * dma_buf_ops.
+ * @attach: [in] attachment to unmap buffer from
+ * @sg_table: [in] scatterlist info of the buffer to unmap
+ *
+ */
+void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
+ struct sg_table *sg_table)
+{
+ if (WARN_ON(!attach || !attach->dmabuf || !sg_table
+ || !attach->dmabuf->ops))
+ return;
+
+ mutex_lock(&attach->dmabuf->lock);
+ if (attach->dmabuf->ops->unmap_dma_buf)
+ attach->dmabuf->ops->unmap_dma_buf(attach, sg_table);
+ mutex_unlock(&attach->dmabuf->lock);
+
+}
+EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment);
--- /dev/null
+/*
+ * Header file for dma buffer sharing framework.
+ *
+ * Copyright(C) 2011 Linaro Limited. All rights reserved.
+ * Author: Sumit Semwal <sumit.semwal@ti.com>
+ *
+ * Many thanks to linaro-mm-sig list, and specially
+ * Arnd Bergmann <arnd@arndb.de>, Rob Clark <rob@ti.com> and
+ * Daniel Vetter <daniel@ffwll.ch> for their support in creation and
+ * refining of this idea.
+ *
+ * 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_H__
+#define __DMA_BUF_H__
+
+#include <linux/file.h>
+#include <linux/err.h>
+#include <linux/device.h>
+#include <linux/scatterlist.h>
+#include <linux/list.h>
+#include <linux/dma-mapping.h>
+
+struct dma_buf;
+struct dma_buf_attachment;
+
+/**
+ * struct dma_buf_ops - operations possible on struct dma_buf
+ * @attach: [optional] allows different devices to 'attach' themselves to the
+ * given buffer. It might return -EBUSY to signal that backing storage
+ * is already allocated and incompatible with the requirements
+ * of requesting device.
+ * @detach: [optional] detach a given device from this buffer.
+ * @map_dma_buf: returns list of scatter pages allocated, increases usecount
+ * of the buffer. Requires atleast one attach to be called
+ * before. Returned sg list should already be mapped into
+ * _device_ address space. This call may sleep. May also return
+ * -EINTR. Should return -EINVAL if attach hasn't been called yet.
+ * @unmap_dma_buf: decreases usecount of buffer, might deallocate scatter
+ * pages.
+ * @release: release this buffer; to be called after the last dma_buf_put.
+ */
+struct dma_buf_ops {
+ int (*attach)(struct dma_buf *, struct device *,
+ struct dma_buf_attachment *);
+
+ void (*detach)(struct dma_buf *, struct dma_buf_attachment *);
+
+ /* For {map,unmap}_dma_buf below, any specific buffer attributes
+ * required should get added to device_dma_parameters accessible
+ * via dev->dma_params.
+ */
+ struct sg_table * (*map_dma_buf)(struct dma_buf_attachment *,
+ enum dma_data_direction);
+ void (*unmap_dma_buf)(struct dma_buf_attachment *,
+ struct sg_table *);
+ /* TODO: Add try_map_dma_buf version, to return immed with -EBUSY
+ * if the call would block.
+ */
+
+ /* after final dma_buf_put() */
+ void (*release)(struct dma_buf *);
+
+};
+
+/**
+ * struct dma_buf - shared buffer object
+ * @size: size of the buffer
+ * @file: file pointer used for sharing buffers across, and for refcounting.
+ * @attachments: list of dma_buf_attachment that denotes all devices attached.
+ * @ops: dma_buf_ops associated with this buffer object.
+ * @priv: exporter specific private data for this buffer object.
+ */
+struct dma_buf {
+ size_t size;
+ struct file *file;
+ struct list_head attachments;
+ const struct dma_buf_ops *ops;
+ /* mutex to serialize list manipulation and other ops */
+ struct mutex lock;
+ void *priv;
+};
+
+/**
+ * struct dma_buf_attachment - holds device-buffer attachment data
+ * @dmabuf: buffer for this attachment.
+ * @dev: device attached to the buffer.
+ * @node: list of dma_buf_attachment.
+ * @priv: exporter specific attachment data.
+ *
+ * This structure holds the attachment information between the dma_buf buffer
+ * and its user device(s). The list contains one attachment struct per device
+ * attached to the buffer.
+ */
+struct dma_buf_attachment {
+ struct dma_buf *dmabuf;
+ struct device *dev;
+ struct list_head node;
+ void *priv;
+};
+
+#ifdef CONFIG_DMA_SHARED_BUFFER
+struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
+ struct device *dev);
+void dma_buf_detach(struct dma_buf *dmabuf,
+ struct dma_buf_attachment *dmabuf_attach);
+struct dma_buf *dma_buf_export(void *priv, struct dma_buf_ops *ops,
+ size_t size, int flags);
+int dma_buf_fd(struct dma_buf *dmabuf);
+struct dma_buf *dma_buf_get(int fd);
+void dma_buf_put(struct dma_buf *dmabuf);
+
+struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *,
+ enum dma_data_direction);
+void dma_buf_unmap_attachment(struct dma_buf_attachment *, struct sg_table *);
+#else
+
+static inline struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
+ struct device *dev)
+{
+ return ERR_PTR(-ENODEV);
+}
+
+static inline void dma_buf_detach(struct dma_buf *dmabuf,
+ struct dma_buf_attachment *dmabuf_attach)
+{
+ return;
+}
+
+static inline struct dma_buf *dma_buf_export(void *priv,
+ struct dma_buf_ops *ops,
+ size_t size, int flags)
+{
+ return ERR_PTR(-ENODEV);
+}
+
+static inline int dma_buf_fd(struct dma_buf *dmabuf)
+{
+ return -ENODEV;
+}
+
+static inline struct dma_buf *dma_buf_get(int fd)
+{
+ return ERR_PTR(-ENODEV);
+}
+
+static inline void dma_buf_put(struct dma_buf *dmabuf)
+{
+ return;
+}
+
+static inline struct sg_table *dma_buf_map_attachment(
+ struct dma_buf_attachment *attach, enum dma_data_direction write)
+{
+ return ERR_PTR(-ENODEV);
+}
+
+static inline void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
+ struct sg_table *sg)
+{
+ return;
+}
+
+#endif /* CONFIG_DMA_SHARED_BUFFER */
+
+#endif /* __DMA_BUF_H__ */
projects / openwrt / staging / blogic.git / commitdiff