1 /************************************************************************** 2 * 3 * Copyright 2010 Pauli Nieminen. 4 * All Rights Reserved. 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a 7 * copy of this software and associated documentation files (the 8 * "Software"), to deal in the Software without restriction, including 9 * without limitation the rights to use, copy, modify, merge, publish, 10 * distribute, sub license, and/or sell copies of the Software, and to 11 * permit persons to whom the Software is furnished to do so, subject to 12 * the following conditions: 13 * 14 * The above copyright notice and this permission notice (including the 15 * next paragraph) shall be included in all copies or substantial portions 16 * of the Software. 17 * 18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 20 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL 21 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, 22 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR 23 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE 24 * USE OR OTHER DEALINGS IN THE SOFTWARE. 25 * 26 * 27 **************************************************************************/ 28 /* 29 * Multipart buffer for coping data which is larger than the page size. 30 * 31 * Authors: 32 * Pauli Nieminen <suokkos-at-gmail-dot-com> 33 */ 34 35 #include <sys/cdefs.h> 36 __FBSDID("$FreeBSD$"); 37 38 #ifndef _DRM_BUFFER_H_ 39 #define _DRM_BUFFER_H_ 40 41 #include <dev/drm2/drmP.h> 42 43 struct drm_buffer { 44 int iterator; 45 int size; 46 char *data[]; 47 }; 48 49 50 /** 51 * Return the index of page that buffer is currently pointing at. 52 */ 53 static inline int drm_buffer_page(struct drm_buffer *buf) 54 { 55 return buf->iterator / PAGE_SIZE; 56 } 57 /** 58 * Return the index of the current byte in the page 59 */ 60 static inline int drm_buffer_index(struct drm_buffer *buf) 61 { 62 return buf->iterator & (PAGE_SIZE - 1); 63 } 64 /** 65 * Return number of bytes that is left to process 66 */ 67 static inline int drm_buffer_unprocessed(struct drm_buffer *buf) 68 { 69 return buf->size - buf->iterator; 70 } 71 72 /** 73 * Advance the buffer iterator number of bytes that is given. 74 */ 75 static inline void drm_buffer_advance(struct drm_buffer *buf, int bytes) 76 { 77 buf->iterator += bytes; 78 } 79 80 /** 81 * Allocate the drm buffer object. 82 * 83 * buf: A pointer to a pointer where the object is stored. 84 * size: The number of bytes to allocate. 85 */ 86 extern int drm_buffer_alloc(struct drm_buffer **buf, int size); 87 88 /** 89 * Copy the user data to the begin of the buffer and reset the processing 90 * iterator. 91 * 92 * user_data: A pointer the data that is copied to the buffer. 93 * size: The Number of bytes to copy. 94 */ 95 extern int drm_buffer_copy_from_user(struct drm_buffer *buf, 96 void __user *user_data, int size); 97 98 /** 99 * Free the drm buffer object 100 */ 101 extern void drm_buffer_free(struct drm_buffer *buf); 102 103 /** 104 * Read an object from buffer that may be split to multiple parts. If object 105 * is not split function just returns the pointer to object in buffer. But in 106 * case of split object data is copied to given stack object that is suplied 107 * by caller. 108 * 109 * The processing location of the buffer is also advanced to the next byte 110 * after the object. 111 * 112 * objsize: The size of the objet in bytes. 113 * stack_obj: A pointer to a memory location where object can be copied. 114 */ 115 extern void *drm_buffer_read_object(struct drm_buffer *buf, 116 int objsize, void *stack_obj); 117 118 /** 119 * Returns the pointer to the dword which is offset number of elements from the 120 * current processing location. 121 * 122 * Caller must make sure that dword is not split in the buffer. This 123 * requirement is easily met if all the sizes of objects in buffer are 124 * multiples of dword and PAGE_SIZE is multiple dword. 125 * 126 * Call to this function doesn't change the processing location. 127 * 128 * offset: The index of the dword relative to the internat iterator. 129 */ 130 static inline void *drm_buffer_pointer_to_dword(struct drm_buffer *buffer, 131 int offset) 132 { 133 int iter = buffer->iterator + offset * 4; 134 return &buffer->data[iter / PAGE_SIZE][iter & (PAGE_SIZE - 1)]; 135 } 136 /** 137 * Returns the pointer to the dword which is offset number of elements from 138 * the current processing location. 139 * 140 * Call to this function doesn't change the processing location. 141 * 142 * offset: The index of the byte relative to the internat iterator. 143 */ 144 static inline void *drm_buffer_pointer_to_byte(struct drm_buffer *buffer, 145 int offset) 146 { 147 int iter = buffer->iterator + offset; 148 return &buffer->data[iter / PAGE_SIZE][iter & (PAGE_SIZE - 1)]; 149 } 150 151 #endif 152