diff options
Diffstat (limited to 'include/drm')
-rw-r--r-- | include/drm/drm_buffer.h | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/include/drm/drm_buffer.h b/include/drm/drm_buffer.h new file mode 100644 index 000000000000..322dbff3f861 --- /dev/null +++ b/include/drm/drm_buffer.h @@ -0,0 +1,148 @@ +/************************************************************************** + * + * Copyright 2010 Pauli Nieminen. + * All Rights Reserved. + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the + * "Software"), to deal in the Software without restriction, including + * without limitation the rights to use, copy, modify, merge, publish, + * distribute, sub license, and/or sell copies of the Software, and to + * permit persons to whom the Software is furnished to do so, subject to + * the following conditions: + * + * The above copyright notice and this permission notice (including the + * next paragraph) shall be included in all copies or substantial portions + * of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL + * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, + * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR + * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE + * USE OR OTHER DEALINGS IN THE SOFTWARE. + * + * + **************************************************************************/ +/* + * Multipart buffer for coping data which is larger than the page size. + * + * Authors: + * Pauli Nieminen <suokkos-at-gmail-dot-com> + */ + +#ifndef _DRM_BUFFER_H_ +#define _DRM_BUFFER_H_ + +#include "drmP.h" + +struct drm_buffer { + int iterator; + int size; + char *data[]; +}; + + +/** + * Return the index of page that buffer is currently pointing at. + */ +static inline int drm_buffer_page(struct drm_buffer *buf) +{ + return buf->iterator / PAGE_SIZE; +} +/** + * Return the index of the current byte in the page + */ +static inline int drm_buffer_index(struct drm_buffer *buf) +{ + return buf->iterator & (PAGE_SIZE - 1); +} +/** + * Return number of bytes that is left to process + */ +static inline int drm_buffer_unprocessed(struct drm_buffer *buf) +{ + return buf->size - buf->iterator; +} + +/** + * Advance the buffer iterator number of bytes that is given. + */ +static inline void drm_buffer_advance(struct drm_buffer *buf, int bytes) +{ + buf->iterator += bytes; +} + +/** + * Allocate the drm buffer object. + * + * buf: A pointer to a pointer where the object is stored. + * size: The number of bytes to allocate. + */ +extern int drm_buffer_alloc(struct drm_buffer **buf, int size); + +/** + * Copy the user data to the begin of the buffer and reset the processing + * iterator. + * + * user_data: A pointer the data that is copied to the buffer. + * size: The Number of bytes to copy. + */ +extern int drm_buffer_copy_from_user(struct drm_buffer *buf, + void __user *user_data, int size); + +/** + * Free the drm buffer object + */ +extern void drm_buffer_free(struct drm_buffer *buf); + +/** + * Read an object from buffer that may be split to multiple parts. If object + * is not split function just returns the pointer to object in buffer. But in + * case of split object data is copied to given stack object that is suplied + * by caller. + * + * The processing location of the buffer is also advanced to the next byte + * after the object. + * + * objsize: The size of the objet in bytes. + * stack_obj: A pointer to a memory location where object can be copied. + */ +extern void *drm_buffer_read_object(struct drm_buffer *buf, + int objsize, void *stack_obj); + +/** + * Returns the pointer to the dword which is offset number of elements from the + * current processing location. + * + * Caller must make sure that dword is not split in the buffer. This + * requirement is easily met if all the sizes of objects in buffer are + * multiples of dword and PAGE_SIZE is multiple dword. + * + * Call to this function doesn't change the processing location. + * + * offset: The index of the dword relative to the internat iterator. + */ +static inline void *drm_buffer_pointer_to_dword(struct drm_buffer *buffer, + int offset) +{ + int iter = buffer->iterator + offset * 4; + return &buffer->data[iter / PAGE_SIZE][iter & (PAGE_SIZE - 1)]; +} +/** + * Returns the pointer to the dword which is offset number of elements from + * the current processing location. + * + * Call to this function doesn't change the processing location. + * + * offset: The index of the byte relative to the internat iterator. + */ +static inline void *drm_buffer_pointer_to_byte(struct drm_buffer *buffer, + int offset) +{ + int iter = buffer->iterator + offset; + return &buffer->data[iter / PAGE_SIZE][iter & (PAGE_SIZE - 1)]; +} + +#endif |