atusb/flash.c

   1 /*
   2  * fw/flash.c - Board-specific flash functions
   3  *
   4  * Written 2011, 2013-2015 by Werner Almesberger
   5  * Copyright 2011, 2013-2015 Werner Almesberger
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  */
  12
  13
  14 #include <stdbool.h>
  15 #include <stdint.h>
  16
  17 #include <avr/boot.h>
  18 #include <avr/pgmspace.h>
  19
  20 #include "dfu.h"
  21 #include "board.h"
  22
  23
  24 static uint32_t payload;
  25
  26
  27 static void flash_start(void)
  28 {
  29         payload = 0;
  30 }
  31
  32
  33 static bool flash_can_write(uint16_t size)
  34 {
  35         return payload+size <= BOOT_ADDR;
  36 }
  37
  38
  39 static void flash_write(const uint8_t *buf, uint16_t size)
  40 {
  41         static uint8_t last;
  42         const uint8_t *p;
  43
  44         for (p = buf; p != buf+size; p++) {
  45                 if (!(payload & (SPM_PAGESIZE-1))) {
  46                         boot_page_erase(payload);
  47                         boot_spm_busy_wait();
  48                 }
  49
  50                 if (payload & 1)
  51                         boot_page_fill(payload, last | (*p << 8));
  52                 else
  53                         last = *p;
  54                 payload++;
  55
  56                 if (!(payload & (SPM_PAGESIZE-1))) {
  57                         boot_page_write(payload-SPM_PAGESIZE);
  58                         boot_spm_busy_wait();
  59                 }
  60         }
  61 }
  62
  63
  64 static void flash_end_write(void)
  65 {
  66         if (payload & (SPM_PAGESIZE-1)) {
  67                 boot_page_write(payload & ~(SPM_PAGESIZE-1));
  68                 boot_spm_busy_wait();
  69         }
  70         boot_rww_enable();
  71 }
  72
  73
  74 static uint16_t flash_read(uint8_t *buf, uint16_t size)
  75 {
  76         uint16_t got = 0;
  77
  78         while (size && payload != (uint32_t) FLASHEND+1) {
  79                 *buf++ = pgm_read_byte(payload);
  80                 payload++;
  81                 size--;
  82                 got++;
  83         }
  84         return got;
  85 }
  86
  87
  88 static const struct dfu_flash_ops flash_ops = {
  89         .start          = flash_start,
  90         .can_write      = flash_can_write,
  91         .write          = flash_write,
  92         .end_write      = flash_end_write,
  93         .read           = flash_read,
  94 };
  95
  96
  97 const struct dfu_flash_ops *dfu_flash_ops = &flash_ops;