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   1 /*
   2  * Copyright © 2009 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_25lc1024.h"
  21
  22 #define EE_BLOCK_SIZE   ((uint16_t) (256))
  23 #define EE_BLOCK_SHIFT  8
  24 #define EE_DEVICE_SIZE  ((uint32_t) 128 * (uint32_t) 1024)
  25
  26 /* Total bytes of available storage */
  27 uint32_t        ao_storage_total;
  28
  29 /* Block size - device is erased in these units. At least 256 bytes */
  30 uint32_t        ao_storage_block;
  31
  32 /* Byte offset of config block. Will be ao_storage_block bytes long */
  33 uint32_t        ao_storage_config;
  34
  35 /* Storage unit size - device reads and writes must be within blocks of this size. Usually 256 bytes. */
  36 uint16_t        ao_storage_unit;
  37
  38 /*
  39  * Using SPI on USART 0, with P1_2 as the chip select
  40  */
  41
  42 #define EE_CS_PORT      P1
  43 #define EE_CS           P1_2
  44 #define EE_CS_PIN       2
  45
  46 static uint8_t ao_ee_mutex;
  47
  48 #define ao_ee_delay() do { \
  49         _asm nop _endasm; \
  50         _asm nop _endasm; \
  51         _asm nop _endasm; \
  52 } while(0)
  53
  54 #define ao_ee_cs_low()  ao_spi_get_bit(EE_CS_PORT, EE_CS_PIN, EE_CS, AO_EE_SPI_BUS, AO_SPI_SPEED_FAST)
  55
  56 #define ao_ee_cs_high() ao_spi_put_bit(EE_CS_PORT, EE_CS_PIN, EE_CS, AO_EE_SPI_BUS)
  57
  58 struct ao_ee_instruction {
  59         uint8_t instruction;
  60         uint8_t address[3];
  61 } ao_ee_instruction;
  62
  63 static void
  64 ao_ee_write_enable(void)
  65 {
  66         ao_ee_cs_low();
  67         ao_ee_instruction.instruction = EE_WREN;
  68         ao_spi_send(&ao_ee_instruction, 1, AO_EE_SPI_BUS);
  69         ao_ee_cs_high();
  70 }
  71
  72 static uint8_t
  73 ao_ee_rdsr(void)
  74 {
  75         ao_ee_cs_low();
  76         ao_ee_instruction.instruction = EE_RDSR;
  77         ao_spi_send(&ao_ee_instruction, 1, AO_EE_SPI_BUS);
  78         ao_spi_recv(&ao_ee_instruction, 1, AO_EE_SPI_BUS);
  79         ao_ee_cs_high();
  80         return ao_ee_instruction.instruction;
  81 }
  82
  83 static void
  84 ao_ee_wrsr(uint8_t status)
  85 {
  86         ao_ee_cs_low();
  87         ao_ee_instruction.instruction = EE_WRSR;
  88         ao_ee_instruction.address[0] = status;
  89         ao_spi_send(&ao_ee_instruction, 2, AO_EE_SPI_BUS);
  90         ao_ee_cs_high();
  91 }
  92
  93 #define EE_BLOCK_NONE   0xffff
  94
  95 static uint8_t ao_ee_data[EE_BLOCK_SIZE];
  96 static uint16_t ao_ee_block = EE_BLOCK_NONE;
  97 static uint8_t  ao_ee_block_dirty;
  98
  99 /* Write the current block to the EEPROM */
 100 static void
 101 ao_ee_write_block(void)
 102 {
 103         uint8_t status;
 104
 105         status = ao_ee_rdsr();
 106         if (status & (EE_STATUS_BP0|EE_STATUS_BP1|EE_STATUS_WPEN)) {
 107                 status &= ~(EE_STATUS_BP0|EE_STATUS_BP1|EE_STATUS_WPEN);
 108                 ao_ee_wrsr(status);
 109         }
 110         ao_ee_write_enable();
 111         ao_ee_cs_low();
 112         ao_ee_instruction.instruction = EE_WRITE;
 113         ao_ee_instruction.address[0] = ao_ee_block >> 8;
 114         ao_ee_instruction.address[1] = ao_ee_block;
 115         ao_ee_instruction.address[2] = 0;
 116         ao_spi_send(&ao_ee_instruction, 4, AO_EE_SPI_BUS);
 117         ao_spi_send(ao_ee_data, EE_BLOCK_SIZE, AO_EE_SPI_BUS);
 118         ao_ee_cs_high();
 119         for (;;) {
 120                 uint8_t status = ao_ee_rdsr();
 121                 if ((status & EE_STATUS_WIP) == 0)
 122                         break;
 123         }
 124 }
 125
 126 /* Read the current block from the EEPROM */
 127 static void
 128 ao_ee_read_block(void)
 129 {
 130         ao_ee_cs_low();
 131         ao_ee_instruction.instruction = EE_READ;
 132         ao_ee_instruction.address[0] = ao_ee_block >> 8;
 133         ao_ee_instruction.address[1] = ao_ee_block;
 134         ao_ee_instruction.address[2] = 0;
 135         ao_spi_send(&ao_ee_instruction, 4, AO_EE_SPI_BUS);
 136         ao_spi_recv(ao_ee_data, EE_BLOCK_SIZE, AO_EE_SPI_BUS);
 137         ao_ee_cs_high();
 138 }
 139
 140 static void
 141 ao_ee_flush_internal(void)
 142 {
 143         if (ao_ee_block_dirty) {
 144                 ao_ee_write_block();
 145                 ao_ee_block_dirty = 0;
 146         }
 147 }
 148
 149 static void
 150 ao_ee_fill(uint16_t block)
 151 {
 152         if (block != ao_ee_block) {
 153                 ao_ee_flush_internal();
 154                 ao_ee_block = block;
 155                 ao_ee_read_block();
 156         }
 157 }
 158
 159 uint8_t
 160 ao_storage_device_write(uint32_t pos, void *buf, uint16_t len)
 161 {
 162         uint16_t block = (uint16_t) (pos >> EE_BLOCK_SHIFT);
 163
 164         /* Transfer the data */
 165         ao_mutex_get(&ao_ee_mutex); {
 166                 if (len != EE_BLOCK_SIZE)
 167                         ao_ee_fill(block);
 168                 else {
 169                         ao_ee_flush_internal();
 170                         ao_ee_block = block;
 171                 }
 172                 memcpy(ao_ee_data + (uint16_t) (pos & 0xff), buf, len);
 173                 ao_ee_block_dirty = 1;
 174         } ao_mutex_put(&ao_ee_mutex);
 175         return 1;
 176 }
 177
 178 uint8_t
 179 ao_storage_device_read(uint32_t pos, void *buf, uint16_t len)
 180 {
 181         uint16_t block = (uint16_t) (pos >> EE_BLOCK_SHIFT);
 182
 183         /* Transfer the data */
 184         ao_mutex_get(&ao_ee_mutex); {
 185                 ao_ee_fill(block);
 186                 memcpy(buf, ao_ee_data + (uint16_t) (pos & 0xff), len);
 187         } ao_mutex_put(&ao_ee_mutex);
 188         return 1;
 189 }
 190
 191 void
 192 ao_storage_flush(void)
 193 {
 194         ao_mutex_get(&ao_ee_mutex); {
 195                 ao_ee_flush_internal();
 196         } ao_mutex_put(&ao_ee_mutex);
 197 }
 198
 199 uint8_t
 200 ao_storage_erase(uint32_t pos)
 201 {
 202         ao_mutex_get(&ao_ee_mutex); {
 203                 ao_ee_flush_internal();
 204                 ao_ee_block = (uint16_t) (pos >> EE_BLOCK_SHIFT);
 205                 memset(ao_ee_data, 0xff, EE_BLOCK_SIZE);
 206                 ao_ee_block_dirty = 1;
 207         } ao_mutex_put(&ao_ee_mutex);
 208         return 1;
 209 }
 210
 211 static void
 212 ee_store(void)
 213 {
 214 }
 215
 216 void
 217 ao_storage_setup(void)
 218 {
 219         if (ao_storage_total == 0) {
 220                 ao_storage_total = EE_DEVICE_SIZE;
 221                 ao_storage_block = EE_BLOCK_SIZE;
 222                 ao_storage_config = EE_DEVICE_SIZE - EE_BLOCK_SIZE;
 223                 ao_storage_unit = EE_BLOCK_SIZE;
 224         }
 225 }
 226
 227 void
 228 ao_storage_device_info(void)
 229 {
 230 }
 231
 232 /*
 233  * To initialize the chip, set up the CS line and
 234  * the SPI interface
 235  */
 236 void
 237 ao_storage_device_init(void)
 238 {
 239         /* set up CS */
 240         ao_enable_output(EE_CS_PORT, EE_CS_PIN, EE_CS, 1);
 241 }