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   1 /*
   2  * Copyright © 2020 Keith Packard <keithp@keithp.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) 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 along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  17  */
  18
  19 #include <ao.h>
  20 #include <ao_flash.h>
  21
  22 static uint8_t
  23 ao_flash_pecr_is_locked(void)
  24 {
  25         return (stm_flash.pecr & (1 << STM_FLASH_PECR_PE_LOCK)) != 0;
  26 }
  27
  28 static uint8_t
  29 ao_flash_pgr_is_locked(void)
  30 {
  31         return (stm_flash.pecr & (1 << STM_FLASH_PECR_PRG_LOCK)) != 0;
  32 }
  33
  34 static void
  35 ao_flash_pecr_unlock(void)
  36 {
  37         if (!ao_flash_pecr_is_locked())
  38                 return;
  39
  40         /* Unlock Data EEPROM and FLASH_PECR register */
  41         stm_flash.pekeyr = STM_FLASH_PEKEYR_PEKEY1;
  42         stm_flash.pekeyr = STM_FLASH_PEKEYR_PEKEY2;
  43         if (ao_flash_pecr_is_locked())
  44                 ao_panic(AO_PANIC_FLASH);
  45 }
  46
  47 static void
  48 ao_flash_pgr_unlock(void)
  49 {
  50         if (!ao_flash_pgr_is_locked())
  51                 return;
  52
  53         /* Unlock program memory */
  54         stm_flash.prgkeyr = STM_FLASH_PRGKEYR_PRGKEY1;
  55         stm_flash.prgkeyr = STM_FLASH_PRGKEYR_PRGKEY2;
  56         if (ao_flash_pgr_is_locked())
  57                 ao_panic(AO_PANIC_FLASH);
  58 }
  59
  60 static void
  61 ao_flash_lock(void)
  62 {
  63         stm_flash.pecr |= (1 << STM_FLASH_PECR_OPT_LOCK) | (1 << STM_FLASH_PECR_PRG_LOCK) | (1 << STM_FLASH_PECR_PE_LOCK);
  64 }
  65
  66 static void
  67 ao_flash_wait_bsy(void)
  68 {
  69         while (stm_flash.sr & (1 << STM_FLASH_SR_BSY))
  70                 ;
  71 }
  72
  73 static void __attribute__ ((section(".sdata2.flash"), noinline))
  74 _ao_flash_erase_page(uint32_t *page)
  75 {
  76         stm_flash.pecr |= (1 << STM_FLASH_PECR_ERASE) | (1 << STM_FLASH_PECR_PROG);
  77
  78         *page = 0x00000000;
  79
  80         ao_flash_wait_bsy();
  81 }
  82
  83 void
  84 ao_flash_erase_page(uint32_t *page)
  85 {
  86         ao_arch_block_interrupts();
  87         ao_flash_pecr_unlock();
  88         ao_flash_pgr_unlock();
  89
  90         _ao_flash_erase_page(page);
  91
  92         ao_flash_lock();
  93         ao_arch_release_interrupts();
  94 }
  95
  96 #if 0
  97 static void __attribute__ ((section(".sdata2.flash"), noinline))
  98 _ao_flash_half_page(uint32_t *dst, uint32_t *src)
  99 {
 100         uint8_t         i;
 101
 102         stm_flash.pecr |= (1 << STM_FLASH_PECR_FPRG);
 103         stm_flash.pecr |= (1 << STM_FLASH_PECR_PROG);
 104
 105         ao_flash_wait_bsy();
 106
 107         for (i = 0; i < 32; i++) {
 108                 *dst++ = *src++;
 109         }
 110
 111         while (stm_flash.sr & (1 << STM_FLASH_SR_BSY))
 112                 ;
 113 }
 114
 115 void
 116 ao_flash_page(uint32_t *page, uint32_t *src)
 117 {
 118         uint8_t         h;
 119
 120         ao_flash_erase_page(page);
 121
 122         ao_arch_block_interrupts();
 123         ao_flash_pecr_unlock();
 124         ao_flash_pgr_unlock();
 125         for (h = 0; h < 2; h++) {
 126                 _ao_flash_half_page(page, src);
 127                 page += 32;
 128                 src += 32;
 129         }
 130         ao_flash_lock();
 131         ao_arch_release_interrupts();
 132 }
 133 #endif
 134
 135 static ao_pos_t write_pos;
 136 static uint8_t write_pending;
 137 static union {
 138         uint32_t        u32;
 139         uint8_t         u8[4];
 140 } write_buf;
 141
 142 void
 143 ao_storage_flush(void)
 144 {
 145         if (write_pending) {
 146                 ao_flash_pecr_unlock();
 147                 ao_flash_pgr_unlock();
 148                 __storage[write_pos] = write_buf.u32;
 149                 ao_flash_lock();
 150                 write_pending = 0;
 151         }
 152 }
 153
 154 /* Read data within a storage unit */
 155 uint8_t
 156 ao_storage_device_read(ao_pos_t pos, void *buf, uint16_t len)
 157 {
 158         memcpy(buf, ((uint8_t *) __storage) + pos, len);
 159         return 1;
 160 }
 161
 162 static void
 163 flash_write_select(ao_pos_t pos)
 164 {
 165         /* Flush any pending writes to another word */
 166         if (write_pending) {
 167                 if (pos == write_pos)
 168                         return;
 169                 __storage[write_pos] = write_buf.u32;
 170                 write_pending = 0;
 171         }
 172         write_pos = pos;
 173 }
 174
 175 /* Write data within a storage unit */
 176 uint8_t
 177 ao_storage_device_write(ao_pos_t pos, void *buf, uint16_t len)
 178 {
 179         uint8_t *b8 = buf;
 180
 181         ao_flash_pecr_unlock();
 182         ao_flash_pgr_unlock();
 183         while (len) {
 184                 ao_pos_t        this_pos = pos >> 2;
 185
 186                 flash_write_select(this_pos);
 187
 188                 /* Update write buffer with new contents */
 189                 uint16_t this_word = 4 - (pos & 3);
 190                 if (this_word > len)
 191                         this_word = len;
 192                 memcpy(&write_buf.u8[pos & 3], b8, this_word);
 193                 pos += this_word;
 194                 len -= this_word;
 195                 b8 += this_word;
 196
 197                 /* If we filled the buffer, flush it out */
 198                 if ((pos & 3) == 0) {
 199                         __storage[write_pos] = write_buf.u32;
 200                 } else {
 201                         write_pending = 1;
 202                 }
 203         }
 204         ao_flash_lock();
 205         return 1;
 206 }
 207
 208 bool
 209 ao_storage_device_is_erased(uint32_t pos)
 210 {
 211         uint8_t *m = ((uint8_t *) __storage) + pos;
 212         uint32_t i;
 213
 214         for (i = 0; i < STM_FLASH_PAGE_SIZE; i++)
 215                 if (*m++ != AO_STORAGE_ERASED_BYTE)
 216                         return false;
 217         return true;
 218 }
 219
 220 /* Erase device from pos through pos + ao_storage_block */
 221 uint8_t
 222 ao_storage_device_erase(uint32_t pos)
 223 {
 224         ao_flash_erase_page(__storage + (pos >> 2));
 225         return 1;
 226 }