/************************************************************************** * * 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 <drm/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