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