Pauli Nieminen | 7a9f0dd | 2010-02-01 19:11:15 +0200 | [diff] [blame^] | 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 | #ifndef _DRM_BUFFER_H_ |
| 36 | #define _DRM_BUFFER_H_ |
| 37 | |
| 38 | #include "drmP.h" |
| 39 | |
| 40 | struct drm_buffer { |
| 41 | int iterator; |
| 42 | int size; |
| 43 | char *data[]; |
| 44 | }; |
| 45 | |
| 46 | |
| 47 | /** |
| 48 | * Return the index of page that buffer is currently pointing at. |
| 49 | */ |
| 50 | static inline int drm_buffer_page(struct drm_buffer *buf) |
| 51 | { |
| 52 | return buf->iterator / PAGE_SIZE; |
| 53 | } |
| 54 | /** |
| 55 | * Return the index of the current byte in the page |
| 56 | */ |
| 57 | static inline int drm_buffer_index(struct drm_buffer *buf) |
| 58 | { |
| 59 | return buf->iterator & (PAGE_SIZE - 1); |
| 60 | } |
| 61 | /** |
| 62 | * Return number of bytes that is left to process |
| 63 | */ |
| 64 | static inline int drm_buffer_unprocessed(struct drm_buffer *buf) |
| 65 | { |
| 66 | return buf->size - buf->iterator; |
| 67 | } |
| 68 | |
| 69 | /** |
| 70 | * Advance the buffer iterator number of bytes that is given. |
| 71 | */ |
| 72 | static inline void drm_buffer_advance(struct drm_buffer *buf, int bytes) |
| 73 | { |
| 74 | buf->iterator += bytes; |
| 75 | } |
| 76 | |
| 77 | /** |
| 78 | * Allocate the drm buffer object. |
| 79 | * |
| 80 | * buf: A pointer to a pointer where the object is stored. |
| 81 | * size: The number of bytes to allocate. |
| 82 | */ |
| 83 | extern int drm_buffer_alloc(struct drm_buffer **buf, int size); |
| 84 | |
| 85 | /** |
| 86 | * Copy the user data to the begin of the buffer and reset the processing |
| 87 | * iterator. |
| 88 | * |
| 89 | * user_data: A pointer the data that is copied to the buffer. |
| 90 | * size: The Number of bytes to copy. |
| 91 | */ |
| 92 | extern int drm_buffer_copy_from_user(struct drm_buffer *buf, |
| 93 | void __user *user_data, int size); |
| 94 | |
| 95 | /** |
| 96 | * Free the drm buffer object |
| 97 | */ |
| 98 | extern void drm_buffer_free(struct drm_buffer *buf); |
| 99 | |
| 100 | /** |
| 101 | * Read an object from buffer that may be split to multiple parts. If object |
| 102 | * is not split function just returns the pointer to object in buffer. But in |
| 103 | * case of split object data is copied to given stack object that is suplied |
| 104 | * by caller. |
| 105 | * |
| 106 | * The processing location of the buffer is also advanced to the next byte |
| 107 | * after the object. |
| 108 | * |
| 109 | * objsize: The size of the objet in bytes. |
| 110 | * stack_obj: A pointer to a memory location where object can be copied. |
| 111 | */ |
| 112 | extern void *drm_buffer_read_object(struct drm_buffer *buf, |
| 113 | int objsize, void *stack_obj); |
| 114 | |
| 115 | /** |
| 116 | * Returns the pointer to the dword which is offset number of elements from the |
| 117 | * current processing location. |
| 118 | * |
| 119 | * Caller must make sure that dword is not split in the buffer. This |
| 120 | * requirement is easily met if all the sizes of objects in buffer are |
| 121 | * multiples of dword and PAGE_SIZE is multiple dword. |
| 122 | * |
| 123 | * Call to this function doesn't change the processing location. |
| 124 | * |
| 125 | * offset: The index of the dword relative to the internat iterator. |
| 126 | */ |
| 127 | static inline void *drm_buffer_pointer_to_dword(struct drm_buffer *buffer, |
| 128 | int offset) |
| 129 | { |
| 130 | int iter = buffer->iterator + offset * 4; |
| 131 | return &buffer->data[iter / PAGE_SIZE][iter & (PAGE_SIZE - 1)]; |
| 132 | } |
| 133 | /** |
| 134 | * Returns the pointer to the dword which is offset number of elements from |
| 135 | * the current processing location. |
| 136 | * |
| 137 | * Call to this function doesn't change the processing location. |
| 138 | * |
| 139 | * offset: The index of the byte relative to the internat iterator. |
| 140 | */ |
| 141 | static inline void *drm_buffer_pointer_to_byte(struct drm_buffer *buffer, |
| 142 | int offset) |
| 143 | { |
| 144 | int iter = buffer->iterator + offset; |
| 145 | return &buffer->data[iter / PAGE_SIZE][iter & (PAGE_SIZE - 1)]; |
| 146 | } |
| 147 | |
| 148 | #endif |