Documentation/core-api/librs.rst

2 Reed-Solomon Library Programming Interface
10 The generic Reed-Solomon Library provides encoding, decoding and error
13 Reed-Solomon codes are used in communication and storage applications to
16 This documentation is provided for developers who want to utilize the
17 functions provided by the library.
27 This chapter provides examples of how to use the library.
30 ------------
32 The init function init_rs returns a pointer to an rs decoder structure,
33 which holds the necessary information for encoding, decoding and error
34 correction with the given polynomial. It either uses an existing
35 matching decoder or creates a new one. On creation all the lookup tables
36 for fast en/decoding are created. The function may take a while, so make
41     /* the Reed Solomon control structure */
54 --------
56 The encoder calculates the Reed-Solomon code over the given data length
57 and stores the result in the parity buffer. Note that the parity buffer
58 must be initialized before calling the encoder.
60 The expanded data can be inverted on the fly by providing a non-zero
61 inversion mask. The expanded data is XOR'ed with the mask. This is used
62 e.g. for FLASH ECC, where the all 0xFF is inverted to an all 0x00. The
63 Reed-Solomon code for all 0x00 is all 0x00. The code is inverted before
67 The databytes are expanded to the given symbol size on the fly. There is
69 the moment. If it is necessary it should be not a big deal to implement
76     /* Initialize the parity buffer */
83 --------
85 The decoder calculates the syndrome over the given data length and the
86 received parity symbols and corrects errors in the data.
88 If a syndrome is available from a hardware decoder then the syndrome
91 The correction of the data buffer can be suppressed by providing a
92 correction pattern buffer and an error location buffer to the decoder.
93 The decoder stores the calculated error location and the correction
94 bitmask in the given buffers. This is useful for hardware decoders which
97 The databytes are expanded to the given symbol size on the fly. There is
99 the moment. If it is necessary it should be not a big deal to implement
141 Note: It's not necessary to give data and received parity to the
164 -------
166 The function free_rs frees the allocated resources, if the caller is
167 the last user of the decoder.
178 This chapter contains the autogenerated documentation of the structures
179 which are used in the Reed-Solomon Library and are relevant for a
182 .. kernel-doc:: include/linux/rslib.h
188 This chapter contains the autogenerated documentation of the
189 Reed-Solomon functions which are exported.
191 .. kernel-doc:: lib/reed_solomon/reed_solomon.c
197 The library code for encoding and decoding was written by Phil Karn.
202             May be used under the terms of the GNU General Public License (GPL)
205 The wrapper functions and interfaces are written by Thomas Gleixner.
210 The following people have contributed to this document: