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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; version 2 of the License.
   7  *
   8  * This program is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  16  */
  17
  18 #include "ao.h"
  19 #include "ao_25lc1024.h"
  20
  21 #define EE_BLOCK_SIZE   ((uint16_t) (256))
  22 #define EE_BLOCK_SHIFT  8
  23 #define EE_DEVICE_SIZE  ((uint32_t) 128 * (uint32_t) 1024)
  24
  25 /* Total bytes of available storage */
  26 __pdata uint32_t        ao_storage_total;
  27
  28 /* Block size - device is erased in these units. At least 256 bytes */
  29 __pdata uint32_t        ao_storage_block;
  30
  31 /* Byte offset of config block. Will be ao_storage_block bytes long */
  32 __pdata uint32_t        ao_storage_config;
  33
  34 /* Storage unit size - device reads and writes must be within blocks of this size. Usually 256 bytes. */
  35 __pdata uint16_t        ao_storage_unit;
  36
  37 /*
  38  * Using SPI on USART 0, with P1_2 as the chip select
  39  */
  40
  41 #define EE_CS           P1_2
  42 #define EE_CS_INDEX     2
  43
  44 static __xdata uint8_t ao_ee_mutex;
  45
  46 #define ao_ee_delay() do { \
  47         _asm nop _endasm; \
  48         _asm nop _endasm; \
  49         _asm nop _endasm; \
  50 } while(0)
  51
  52 #define ao_ee_cs_low()  ao_spi_get_bit(EE_CS)
  53
  54 #define ao_ee_cs_high() ao_spi_put_bit(EE_CS)
  55
  56 struct ao_ee_instruction {
  57         uint8_t instruction;
  58         uint8_t address[3];
  59 } __xdata ao_ee_instruction;
  60
  61 static void
  62 ao_ee_write_enable(void)
  63 {
  64         ao_ee_cs_low();
  65         ao_ee_instruction.instruction = EE_WREN;
  66         ao_spi_send(&ao_ee_instruction, 1);
  67         ao_ee_cs_high();
  68 }
  69
  70 static uint8_t
  71 ao_ee_rdsr(void)
  72 {
  73         ao_ee_cs_low();
  74         ao_ee_instruction.instruction = EE_RDSR;
  75         ao_spi_send(&ao_ee_instruction, 1);
  76         ao_spi_recv(&ao_ee_instruction, 1);
  77         ao_ee_cs_high();
  78         return ao_ee_instruction.instruction;
  79 }
  80
  81 static void
  82 ao_ee_wrsr(uint8_t status)
  83 {
  84         ao_ee_cs_low();
  85         ao_ee_instruction.instruction = EE_WRSR;
  86         ao_ee_instruction.address[0] = status;
  87         ao_spi_send(&ao_ee_instruction, 2);
  88         ao_ee_cs_high();
  89 }
  90
  91 #define EE_BLOCK_NONE   0xffff
  92
  93 static __xdata uint8_t ao_ee_data[EE_BLOCK_SIZE];
  94 static __pdata uint16_t ao_ee_block = EE_BLOCK_NONE;
  95 static __pdata uint8_t  ao_ee_block_dirty;
  96
  97 /* Write the current block to the EEPROM */
  98 static void
  99 ao_ee_write_block(void)
 100 {
 101         uint8_t status;
 102
 103         status = ao_ee_rdsr();
 104         if (status & (EE_STATUS_BP0|EE_STATUS_BP1|EE_STATUS_WPEN)) {
 105                 status &= ~(EE_STATUS_BP0|EE_STATUS_BP1|EE_STATUS_WPEN);
 106                 ao_ee_wrsr(status);
 107         }
 108         ao_ee_write_enable();
 109         ao_ee_cs_low();
 110         ao_ee_instruction.instruction = EE_WRITE;
 111         ao_ee_instruction.address[0] = ao_ee_block >> 8;
 112         ao_ee_instruction.address[1] = ao_ee_block;
 113         ao_ee_instruction.address[2] = 0;
 114         ao_spi_send(&ao_ee_instruction, 4);
 115         ao_spi_send(ao_ee_data, EE_BLOCK_SIZE);
 116         ao_ee_cs_high();
 117         for (;;) {
 118                 uint8_t status = ao_ee_rdsr();
 119                 if ((status & EE_STATUS_WIP) == 0)
 120                         break;
 121         }
 122 }
 123
 124 /* Read the current block from the EEPROM */
 125 static void
 126 ao_ee_read_block(void)
 127 {
 128         ao_ee_cs_low();
 129         ao_ee_instruction.instruction = EE_READ;
 130         ao_ee_instruction.address[0] = ao_ee_block >> 8;
 131         ao_ee_instruction.address[1] = ao_ee_block;
 132         ao_ee_instruction.address[2] = 0;
 133         ao_spi_send(&ao_ee_instruction, 4);
 134         ao_spi_recv(ao_ee_data, EE_BLOCK_SIZE);
 135         ao_ee_cs_high();
 136 }
 137
 138 static void
 139 ao_ee_flush_internal(void)
 140 {
 141         if (ao_ee_block_dirty) {
 142                 ao_ee_write_block();
 143                 ao_ee_block_dirty = 0;
 144         }
 145 }
 146
 147 static void
 148 ao_ee_fill(uint16_t block)
 149 {
 150         if (block != ao_ee_block) {
 151                 ao_ee_flush_internal();
 152                 ao_ee_block = block;
 153                 ao_ee_read_block();
 154         }
 155 }
 156
 157 uint8_t
 158 ao_storage_device_write(uint32_t pos, __xdata void *buf, uint16_t len) __reentrant
 159 {
 160         uint16_t block = (uint16_t) (pos >> EE_BLOCK_SHIFT);
 161
 162         /* Transfer the data */
 163         ao_mutex_get(&ao_ee_mutex); {
 164                 if (len != EE_BLOCK_SIZE)
 165                         ao_ee_fill(block);
 166                 else {
 167                         ao_ee_flush_internal();
 168                         ao_ee_block = block;
 169                 }
 170                 memcpy(ao_ee_data + (uint16_t) (pos & 0xff), buf, len);
 171                 ao_ee_block_dirty = 1;
 172         } ao_mutex_put(&ao_ee_mutex);
 173         return 1;
 174 }
 175
 176 uint8_t
 177 ao_storage_device_read(uint32_t pos, __xdata void *buf, uint16_t len) __reentrant
 178 {
 179         uint16_t block = (uint16_t) (pos >> EE_BLOCK_SHIFT);
 180
 181         /* Transfer the data */
 182         ao_mutex_get(&ao_ee_mutex); {
 183                 ao_ee_fill(block);
 184                 memcpy(buf, ao_ee_data + (uint16_t) (pos & 0xff), len);
 185         } ao_mutex_put(&ao_ee_mutex);
 186         return 1;
 187 }
 188
 189 void
 190 ao_storage_flush(void) __reentrant
 191 {
 192         ao_mutex_get(&ao_ee_mutex); {
 193                 ao_ee_flush_internal();
 194         } ao_mutex_put(&ao_ee_mutex);
 195 }
 196
 197 uint8_t
 198 ao_storage_erase(uint32_t pos) __reentrant
 199 {
 200         ao_mutex_get(&ao_ee_mutex); {
 201                 ao_ee_flush_internal();
 202                 ao_ee_block = (uint16_t) (pos >> EE_BLOCK_SHIFT);
 203                 memset(ao_ee_data, 0xff, EE_BLOCK_SIZE);
 204                 ao_ee_block_dirty = 1;
 205         } ao_mutex_put(&ao_ee_mutex);
 206         return 1;
 207 }
 208
 209 static void
 210 ee_store(void) __reentrant
 211 {
 212 }
 213
 214 void
 215 ao_storage_setup(void)
 216 {
 217         if (ao_storage_total == 0) {
 218                 ao_storage_total = EE_DEVICE_SIZE;
 219                 ao_storage_block = EE_BLOCK_SIZE;
 220                 ao_storage_config = EE_DEVICE_SIZE - EE_BLOCK_SIZE;
 221                 ao_storage_unit = EE_BLOCK_SIZE;
 222         }
 223 }
 224
 225 void
 226 ao_storage_device_info(void) __reentrant
 227 {
 228 }
 229
 230 /*
 231  * To initialize the chip, set up the CS line and
 232  * the SPI interface
 233  */
 234 void
 235 ao_storage_device_init(void)
 236 {
 237         /* set up CS */
 238         EE_CS = 1;
 239         P1DIR |= (1 << EE_CS_INDEX);
 240         P1SEL &= ~(1 << EE_CS_INDEX);
 241 }