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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 "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 static void ao_ee_cs_low(void)
  53 {
  54         ao_ee_delay();
  55         EE_CS = 0;
  56         ao_ee_delay();
  57 }
  58
  59 static void ao_ee_cs_high(void)
  60 {
  61         ao_ee_delay();
  62         EE_CS = 1;
  63         ao_ee_delay();
  64 }
  65
  66 struct ao_ee_instruction {
  67         uint8_t instruction;
  68         uint8_t address[3];
  69 } __xdata ao_ee_instruction;
  70
  71 static void
  72 ao_ee_write_enable(void)
  73 {
  74         ao_ee_cs_low();
  75         ao_ee_instruction.instruction = EE_WREN;
  76         ao_spi_send(&ao_ee_instruction, 1);
  77         ao_ee_cs_high();
  78 }
  79
  80 static uint8_t
  81 ao_ee_rdsr(void)
  82 {
  83         ao_ee_cs_low();
  84         ao_ee_instruction.instruction = EE_RDSR;
  85         ao_spi_send(&ao_ee_instruction, 1);
  86         ao_spi_recv(&ao_ee_instruction, 1);
  87         ao_ee_cs_high();
  88         return ao_ee_instruction.instruction;
  89 }
  90
  91 static void
  92 ao_ee_wrsr(uint8_t status)
  93 {
  94         ao_ee_cs_low();
  95         ao_ee_instruction.instruction = EE_WRSR;
  96         ao_ee_instruction.address[0] = status;
  97         ao_spi_send(&ao_ee_instruction, 2);
  98         ao_ee_cs_high();
  99 }
 100
 101 #define EE_BLOCK_NONE   0xffff
 102
 103 static __xdata uint8_t ao_ee_data[EE_BLOCK_SIZE];
 104 static __pdata uint16_t ao_ee_block = EE_BLOCK_NONE;
 105 static __pdata uint8_t  ao_ee_block_dirty;
 106
 107 /* Write the current block to the EEPROM */
 108 static void
 109 ao_ee_write_block(void)
 110 {
 111         uint8_t status;
 112
 113         status = ao_ee_rdsr();
 114         if (status & (EE_STATUS_BP0|EE_STATUS_BP1|EE_STATUS_WPEN)) {
 115                 status &= ~(EE_STATUS_BP0|EE_STATUS_BP1|EE_STATUS_WPEN);
 116                 ao_ee_wrsr(status);
 117         }
 118         ao_ee_write_enable();
 119         ao_ee_cs_low();
 120         ao_ee_instruction.instruction = EE_WRITE;
 121         ao_ee_instruction.address[0] = ao_ee_block >> 8;
 122         ao_ee_instruction.address[1] = ao_ee_block;
 123         ao_ee_instruction.address[2] = 0;
 124         ao_spi_send(&ao_ee_instruction, 4);
 125         ao_spi_send(ao_ee_data, EE_BLOCK_SIZE);
 126         ao_ee_cs_high();
 127         for (;;) {
 128                 uint8_t status = ao_ee_rdsr();
 129                 if ((status & EE_STATUS_WIP) == 0)
 130                         break;
 131         }
 132 }
 133
 134 /* Read the current block from the EEPROM */
 135 static void
 136 ao_ee_read_block(void)
 137 {
 138         ao_ee_cs_low();
 139         ao_ee_instruction.instruction = EE_READ;
 140         ao_ee_instruction.address[0] = ao_ee_block >> 8;
 141         ao_ee_instruction.address[1] = ao_ee_block;
 142         ao_ee_instruction.address[2] = 0;
 143         ao_spi_send(&ao_ee_instruction, 4);
 144         ao_spi_recv(ao_ee_data, EE_BLOCK_SIZE);
 145         ao_ee_cs_high();
 146 }
 147
 148 static void
 149 ao_ee_flush_internal(void)
 150 {
 151         if (ao_ee_block_dirty) {
 152                 ao_ee_write_block();
 153                 ao_ee_block_dirty = 0;
 154         }
 155 }
 156
 157 static void
 158 ao_ee_fill(uint16_t block)
 159 {
 160         if (block != ao_ee_block) {
 161                 ao_ee_flush_internal();
 162                 ao_ee_block = block;
 163                 ao_ee_read_block();
 164         }
 165 }
 166
 167 uint8_t
 168 ao_storage_device_write(uint32_t pos, __xdata void *buf, uint16_t len) __reentrant
 169 {
 170         uint16_t block = (uint16_t) (pos >> EE_BLOCK_SHIFT);
 171
 172         /* Transfer the data */
 173         ao_mutex_get(&ao_ee_mutex); {
 174                 if (len != EE_BLOCK_SIZE)
 175                         ao_ee_fill(block);
 176                 else {
 177                         ao_ee_flush_internal();
 178                         ao_ee_block = block;
 179                 }
 180                 memcpy(ao_ee_data + (uint16_t) (pos & 0xff), buf, len);
 181                 ao_ee_block_dirty = 1;
 182         } ao_mutex_put(&ao_ee_mutex);
 183         return 1;
 184 }
 185
 186 uint8_t
 187 ao_storage_device_read(uint32_t pos, __xdata void *buf, uint16_t len) __reentrant
 188 {
 189         uint16_t block = (uint16_t) (pos >> EE_BLOCK_SHIFT);
 190
 191         /* Transfer the data */
 192         ao_mutex_get(&ao_ee_mutex); {
 193                 ao_ee_fill(block);
 194                 memcpy(buf, ao_ee_data + (uint16_t) (pos & 0xff), len);
 195         } ao_mutex_put(&ao_ee_mutex);
 196         return 1;
 197 }
 198
 199 void
 200 ao_storage_flush(void) __reentrant
 201 {
 202         ao_mutex_get(&ao_ee_mutex); {
 203                 ao_ee_flush_internal();
 204         } ao_mutex_put(&ao_ee_mutex);
 205 }
 206
 207 uint8_t
 208 ao_storage_erase(uint32_t pos) __reentrant
 209 {
 210         ao_mutex_get(&ao_ee_mutex); {
 211                 ao_ee_flush_internal();
 212                 ao_ee_block = (uint16_t) (pos >> EE_BLOCK_SHIFT);
 213                 memset(ao_ee_data, 0xff, EE_BLOCK_SIZE);
 214                 ao_ee_block_dirty = 1;
 215         } ao_mutex_put(&ao_ee_mutex);
 216         return 1;
 217 }
 218
 219 static void
 220 ee_store(void) __reentrant
 221 {
 222 }
 223
 224 void
 225 ao_storage_setup(void)
 226 {
 227         if (ao_storage_total == 0) {
 228                 ao_storage_total = EE_DEVICE_SIZE;
 229                 ao_storage_block = EE_BLOCK_SIZE;
 230                 ao_storage_config = EE_DEVICE_SIZE - EE_BLOCK_SIZE;
 231                 ao_storage_unit = EE_BLOCK_SIZE;
 232         }
 233 }
 234
 235 void
 236 ao_storage_device_info(void) __reentrant
 237 {
 238 }
 239
 240 /*
 241  * To initialize the chip, set up the CS line and
 242  * the SPI interface
 243  */
 244 void
 245 ao_storage_device_init(void)
 246 {
 247         /* set up CS */
 248         EE_CS = 1;
 249         P1DIR |= (1 << EE_CS_INDEX);
 250         P1SEL &= ~(1 << EE_CS_INDEX);
 251 }