src/drivers/nvs/nvs.c

   1 /*
   2  * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License as
   6  * published by the Free Software Foundation; either version 2 of the
   7  * License, or any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  17  * 02110-1301, USA.
  18  *
  19  * You can also choose to distribute this program under the terms of
  20  * the Unmodified Binary Distribution Licence (as given in the file
  21  * COPYING.UBDL), provided that you have satisfied its requirements.
  22  */
  23
  24 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
  25
  26 #include <stdint.h>
  27 #include <string.h>
  28 #include <errno.h>
  29 #include <assert.h>
  30 #include <ipxe/nvs.h>
  31
  32 /** @file
  33  *
  34  * Non-volatile storage
  35  *
  36  */
  37
  38 /**
  39  * Calculate length up to next block boundary
  40  *
  41  * @v nvs               NVS device
  42  * @v address           Starting address
  43  * @v max_len           Maximum length
  44  * @ret len             Length to use, stopping at block boundaries
  45  */
  46 static size_t nvs_frag_len ( struct nvs_device *nvs, unsigned int address,
  47                              size_t max_len ) {
  48         size_t frag_len;
  49
  50         /* If there are no block boundaries, return the maximum length */
  51         if ( ! nvs->block_size )
  52                 return max_len;
  53
  54         /* Calculate space remaining up to next block boundary */
  55         frag_len = ( ( nvs->block_size -
  56                        ( address & ( nvs->block_size - 1 ) ) )
  57                      << nvs->word_len_log2 );
  58
  59         /* Limit to maximum length */
  60         if ( max_len < frag_len )
  61                 return max_len;
  62
  63         return frag_len;
  64 }
  65
  66 /**
  67  * Read from non-volatile storage device
  68  *
  69  * @v nvs               NVS device
  70  * @v address           Address from which to read
  71  * @v data              Data buffer
  72  * @v len               Length of data buffer
  73  * @ret rc              Return status code
  74  */
  75 int nvs_read ( struct nvs_device *nvs, unsigned int address,
  76                void *data, size_t len ) {
  77         size_t frag_len;
  78         int rc;
  79
  80         /* We don't even attempt to handle buffer lengths that aren't
  81          * an integral number of words.
  82          */
  83         assert ( ( len & ( ( 1 << nvs->word_len_log2 ) - 1 ) ) == 0 );
  84
  85         while ( len ) {
  86
  87                 /* Calculate length to read, stopping at block boundaries */
  88                 frag_len = nvs_frag_len ( nvs, address, len );
  89
  90                 /* Read this portion of the buffer from the device */
  91                 if ( ( rc = nvs->read ( nvs, address, data, frag_len ) ) != 0 )
  92                         return rc;
  93
  94                 /* Update parameters */
  95                 data += frag_len;
  96                 address += ( frag_len >> nvs->word_len_log2 );
  97                 len -= frag_len;
  98         }
  99
 100         return 0;
 101 }
 102
 103 /**
 104  * Verify content of non-volatile storage device
 105  *
 106  * @v nvs               NVS device
 107  * @v address           Address from which to read
 108  * @v data              Data to compare against
 109  * @v len               Length of data buffer
 110  * @ret rc              Return status code
 111  */
 112 static int nvs_verify ( struct nvs_device *nvs, unsigned int address,
 113                         const void *data, size_t len ) {
 114         uint8_t read_data[len];
 115         int rc;
 116
 117         /* Read data into temporary buffer */
 118         if ( ( rc = nvs_read ( nvs, address, read_data, len ) ) != 0 )
 119                 return rc;
 120
 121         /* Compare data */
 122         if ( memcmp ( data, read_data, len ) != 0 ) {
 123                 DBG ( "NVS %p verification failed at %#04x+%zd\n",
 124                       nvs, address, len );
 125                 return -EIO;
 126         }
 127
 128         return 0;
 129 }
 130
 131 /**
 132  * Write to non-volatile storage device
 133  *
 134  * @v nvs               NVS device
 135  * @v address           Address to which to write
 136  * @v data              Data buffer
 137  * @v len               Length of data buffer
 138  * @ret rc              Return status code
 139  */
 140 int nvs_write ( struct nvs_device *nvs, unsigned int address,
 141                 const void *data, size_t len ) {
 142         size_t frag_len;
 143         int rc;
 144
 145         /* We don't even attempt to handle buffer lengths that aren't
 146          * an integral number of words.
 147          */
 148         assert ( ( len & ( ( 1 << nvs->word_len_log2 ) - 1 ) ) == 0 );
 149
 150         while ( len ) {
 151
 152                 /* Calculate length to write, stopping at block boundaries */
 153                 frag_len = nvs_frag_len ( nvs, address, len );
 154
 155                 /* Write this portion of the buffer to the device */
 156                 if ( ( rc = nvs->write ( nvs, address, data, frag_len ) ) != 0)
 157                         return rc;
 158
 159                 /* Read back and verify data */
 160                 if ( ( rc = nvs_verify ( nvs, address, data, frag_len ) ) != 0)
 161                         return rc;
 162
 163                 /* Update parameters */
 164                 data += frag_len;
 165                 address += ( frag_len >> nvs->word_len_log2 );
 166                 len -= frag_len;
 167         }
 168
 169         return 0;
 170 }