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., 675 Mass Ave, Cambridge, MA 02139, USA.
  17  */
  18
  19 FILE_LICENCE ( GPL2_OR_LATER );
  20
  21 #include <stdint.h>
  22 #include <string.h>
  23 #include <errno.h>
  24 #include <assert.h>
  25 #include <gpxe/nvs.h>
  26
  27 /** @file
  28  *
  29  * Non-volatile storage
  30  *
  31  */
  32
  33 /**
  34  * Read from non-volatile storage device
  35  *
  36  * @v nvs               NVS device
  37  * @v address           Address from which to read
  38  * @v data              Data buffer
  39  * @v len               Length of data buffer
  40  * @ret rc              Return status code
  41  */
  42 int nvs_read ( struct nvs_device *nvs, unsigned int address,
  43                void *data, size_t len ) {
  44         size_t frag_len;
  45         int rc;
  46
  47         /* We don't even attempt to handle buffer lengths that aren't
  48          * an integral number of words.
  49          */
  50         assert ( ( len & ( ( 1 << nvs->word_len_log2 ) - 1 ) ) == 0 );
  51
  52         while ( 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 space remaining in buffer */
  60                 if ( frag_len > len )
  61                         frag_len = len;
  62
  63                 /* Read this portion of the buffer from the device */
  64                 if ( ( rc = nvs->read ( nvs, address, data, frag_len ) ) != 0 )
  65                         return rc;
  66
  67                 /* Update parameters */
  68                 data += frag_len;
  69                 address += ( frag_len >> nvs->word_len_log2 );
  70                 len -= frag_len;
  71         }
  72
  73         return 0;
  74 }
  75
  76 /**
  77  * Verify content of non-volatile storage device
  78  *
  79  * @v nvs               NVS device
  80  * @v address           Address from which to read
  81  * @v data              Data to compare against
  82  * @v len               Length of data buffer
  83  * @ret rc              Return status code
  84  */
  85 static int nvs_verify ( struct nvs_device *nvs, unsigned int address,
  86                         const void *data, size_t len ) {
  87         uint8_t read_data[len];
  88         int rc;
  89
  90         /* Read data into temporary buffer */
  91         if ( ( rc = nvs_read ( nvs, address, read_data, len ) ) != 0 )
  92                 return rc;
  93
  94         /* Compare data */
  95         if ( memcmp ( data, read_data, len ) != 0 ) {
  96                 DBG ( "NVS %p verification failed at %#04x+%zd\n",
  97                       nvs, address, len );
  98                 return -EIO;
  99         }
 100
 101         return 0;
 102 }
 103
 104 /**
 105  * Write to non-volatile storage device
 106  *
 107  * @v nvs               NVS device
 108  * @v address           Address to which to write
 109  * @v data              Data buffer
 110  * @v len               Length of data buffer
 111  * @ret rc              Return status code
 112  */
 113 int nvs_write ( struct nvs_device *nvs, unsigned int address,
 114                 const void *data, size_t len ) {
 115         size_t frag_len;
 116         int rc;
 117
 118         /* We don't even attempt to handle buffer lengths that aren't
 119          * an integral number of words.
 120          */
 121         assert ( ( len & ( ( 1 << nvs->word_len_log2 ) - 1 ) ) == 0 );
 122
 123         while ( len ) {
 124
 125                 /* Calculate space remaining up to next block boundary */
 126                 frag_len = ( ( nvs->block_size -
 127                                ( address & ( nvs->block_size - 1 ) ) )
 128                              << nvs->word_len_log2 );
 129
 130                 /* Limit to space remaining in buffer */
 131                 if ( frag_len > len )
 132                         frag_len = len;
 133
 134                 /* Write this portion of the buffer to the device */
 135                 if ( ( rc = nvs->write ( nvs, address, data, frag_len ) ) != 0)
 136                         return rc;
 137
 138                 /* Read back and verify data */
 139                 if ( ( rc = nvs_verify ( nvs, address, data, frag_len ) ) != 0)
 140                         return rc;
 141
 142                 /* Update parameters */
 143                 data += frag_len;
 144                 address += ( frag_len >> nvs->word_len_log2 );
 145                 len -= frag_len;
 146         }
 147
 148         return 0;
 149 }