[292] | 1 | /** |
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| 2 | * \file : sdcard.c |
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| 3 | * \date : 30 August 2012 |
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| 4 | * \author : Cesar Fuguet |
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| 5 | * |
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| 6 | * This file defines the driver of a SD Card device using an SPI controller |
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| 7 | */ |
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| 8 | |
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| 9 | #include <sdcard.h> |
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| 10 | |
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| 11 | /** |
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| 12 | * \param sdcard: Initialized pointer to the block device |
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| 13 | * |
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| 14 | * \return void |
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| 15 | * |
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| 16 | * \brief Enable SD Card select signal |
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| 17 | */ |
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| 18 | static void _sdcard_enable(struct sdcard_dev * sdcard) |
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| 19 | { |
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| 20 | spi_ss_assert(sdcard->spi, sdcard->slave_id); |
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| 21 | } |
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| 22 | |
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| 23 | /** |
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| 24 | * \param sdcard: Initialized pointer to the block device |
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| 25 | * |
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| 26 | * \return void |
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| 27 | * |
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| 28 | * \brief Disable SD Card select signal |
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| 29 | */ |
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| 30 | static void _sdcard_disable(struct sdcard_dev * sdcard) |
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| 31 | { |
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| 32 | spi_ss_deassert(sdcard->spi, sdcard->slave_id); |
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| 33 | } |
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| 34 | |
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| 35 | /** |
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| 36 | * \param tick_count: SD Card clock ticks number |
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| 37 | * |
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| 38 | * \return void |
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| 39 | * |
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| 40 | * \brief Enable SD Card clock |
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| 41 | * The tick count is byte measured (1 tick, 8 clock) |
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| 42 | */ |
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| 43 | static void _sdcard_gen_tick(struct sdcard_dev * sdcard, unsigned int tick_count) |
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| 44 | { |
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[388] | 45 | register int i = 0; |
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[292] | 46 | while(i++ < tick_count) spi_put_tx(sdcard->spi, 0xFF, 0); |
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| 47 | } |
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| 48 | |
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| 49 | /** |
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| 50 | * \param sdcard: Initialized pointer to the block device |
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| 51 | * |
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| 52 | * \return char from the SD card |
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| 53 | * |
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| 54 | * \brief Get a byte from the SD Card |
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| 55 | */ |
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| 56 | static unsigned char _sdcard_receive_char(struct sdcard_dev * sdcard) |
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| 57 | { |
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| 58 | _sdcard_gen_tick(sdcard, 1); |
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| 59 | |
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| 60 | return spi_get_rx(sdcard->spi, 0); |
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| 61 | } |
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| 62 | |
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| 63 | /** |
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| 64 | * \param sdcard: Initialized pointer to the block device |
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| 65 | * |
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| 66 | * \return sdcard response |
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| 67 | * |
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| 68 | * \brief Wait for a valid response after the send of a command |
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| 69 | * This function can return if one of the next two conditions are true: |
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| 70 | * 1. Bit valid received |
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| 71 | * 2. Timeout (not valid bit received after SDCARD_COMMAND_TIMEOUT |
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| 72 | * wait ticks) |
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| 73 | */ |
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| 74 | static unsigned char _sdcard_wait_response(struct sdcard_dev * sdcard) |
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| 75 | { |
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| 76 | unsigned char sdcard_rsp; |
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| 77 | register int iter; |
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| 78 | |
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| 79 | iter = 0; |
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| 80 | sdcard_rsp = _sdcard_receive_char(sdcard); |
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| 81 | while ( |
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| 82 | (iter < SDCARD_COMMAND_TIMEOUT) && |
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| 83 | !SDCARD_CHECK_R1_VALID(sdcard_rsp) |
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| 84 | ) |
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| 85 | { |
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| 86 | sdcard_rsp = _sdcard_receive_char(sdcard); |
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| 87 | iter++; |
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| 88 | } |
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| 89 | |
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| 90 | return sdcard_rsp; |
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| 91 | } |
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| 92 | |
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| 93 | /** |
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| 94 | * \params sdcard: Initialized pointer to the block device |
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| 95 | * |
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| 96 | * \return void |
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| 97 | * |
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| 98 | * \brief Wait data block start marker |
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| 99 | */ |
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| 100 | static void _sdcard_wait_data_block(struct sdcard_dev * sdcard) |
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| 101 | { |
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| 102 | while (_sdcard_receive_char(sdcard) != 0xFE); |
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| 103 | } |
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| 104 | |
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| 105 | /** |
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| 106 | * \param sdcard : Initialized pointer to block device |
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| 107 | * \param index : SD card CMD index |
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| 108 | * \param app : Type of command, 0 for normal command or 1 for application specific |
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| 109 | * \param args : SD card CMD arguments |
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| 110 | * |
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| 111 | * \return response first byte |
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| 112 | * |
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| 113 | * \brief Send command to the SD card |
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| 114 | */ |
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| 115 | static int _sdcard_send_command ( |
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| 116 | struct sdcard_dev * sdcard , |
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| 117 | int index , |
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| 118 | int app , |
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| 119 | void * args , |
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| 120 | unsigned crc7 ) |
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| 121 | { |
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| 122 | unsigned char sdcard_rsp; |
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| 123 | unsigned char * _args; |
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| 124 | |
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| 125 | _sdcard_gen_tick(sdcard, 5); |
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| 126 | |
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| 127 | if (app == SDCARD_ACMD) |
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| 128 | { |
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| 129 | spi_put_tx(sdcard->spi, 0x40 | 55 , 0 );/* CMD and START bit */ |
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| 130 | spi_put_tx(sdcard->spi, 0x00 , 0 );/* Argument[0] */ |
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| 131 | spi_put_tx(sdcard->spi, 0x00 , 0 );/* Argument[1] */ |
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| 132 | spi_put_tx(sdcard->spi, 0x00 , 0 );/* Argument[2] */ |
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| 133 | spi_put_tx(sdcard->spi, 0x00 , 0 );/* Argument[3] */ |
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| 134 | spi_put_tx(sdcard->spi, 0x01 | (crc7 << 1), 0 );/* END bit */ |
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| 135 | |
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| 136 | sdcard_rsp = _sdcard_wait_response(sdcard); |
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| 137 | if (SDCARD_CHECK_R1_ERROR(sdcard_rsp)) |
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| 138 | { |
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| 139 | return sdcard_rsp; |
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| 140 | } |
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| 141 | } |
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| 142 | |
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| 143 | _args = (unsigned char *) args; |
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| 144 | |
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| 145 | _sdcard_gen_tick(sdcard, 1); |
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| 146 | |
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| 147 | spi_put_tx(sdcard->spi, 0x40 | index , 0 ); |
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| 148 | spi_put_tx(sdcard->spi, _args[0] , 0 ); |
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| 149 | spi_put_tx(sdcard->spi, _args[1] , 0 ); |
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| 150 | spi_put_tx(sdcard->spi, _args[2] , 0 ); |
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| 151 | spi_put_tx(sdcard->spi, _args[3] , 0 ); |
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| 152 | spi_put_tx(sdcard->spi, 0x01 | (crc7 << 1), 0 ); |
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| 153 | |
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| 154 | return _sdcard_wait_response(sdcard); |
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| 155 | } |
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| 156 | |
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| 157 | int sdcard_dev_open(struct sdcard_dev * sdcard, struct spi_dev * spi, int ss) |
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| 158 | { |
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| 159 | unsigned char args[4]; |
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| 160 | unsigned char sdcard_rsp; |
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| 161 | unsigned int iter; |
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| 162 | |
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| 163 | sdcard->spi = spi; |
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| 164 | sdcard->slave_id = ss; |
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| 165 | |
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| 166 | /* |
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| 167 | * Supply SD card ramp up time (min 74 cycles) |
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| 168 | */ |
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| 169 | _sdcard_gen_tick(sdcard, 10); |
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| 170 | |
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| 171 | /* |
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| 172 | * Assert slave select signal |
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| 173 | * Send CMD0 (Reset Command) |
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| 174 | * Deassert slave select signal |
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| 175 | */ |
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| 176 | _sdcard_enable(sdcard); |
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| 177 | |
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| 178 | args[0] = 0; |
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| 179 | args[1] = 0; |
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| 180 | args[2] = 0; |
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| 181 | args[3] = 0; |
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| 182 | sdcard_rsp = _sdcard_send_command(sdcard, 0, SDCARD_CMD, args, 0x4A); |
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| 183 | if ( sdcard_rsp != 0x01 ) |
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| 184 | { |
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| 185 | return sdcard_rsp; |
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| 186 | } |
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| 187 | |
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| 188 | _sdcard_disable(sdcard); |
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| 189 | _sdcard_enable(sdcard); |
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| 190 | |
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| 191 | iter = 0; |
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| 192 | while( iter++ < SDCARD_COMMAND_TIMEOUT ) |
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| 193 | { |
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| 194 | sdcard_rsp = _sdcard_send_command(sdcard, 41, SDCARD_ACMD, args, 0x00); |
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| 195 | if( sdcard_rsp == 0x01 ) |
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| 196 | { |
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| 197 | continue; |
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| 198 | } |
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| 199 | |
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| 200 | break; |
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| 201 | } |
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| 202 | |
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| 203 | _sdcard_disable(sdcard); |
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| 204 | |
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| 205 | return sdcard_rsp; |
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| 206 | } |
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| 207 | |
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| 208 | int sdcard_dev_read(struct sdcard_dev * sdcard, void * buf, unsigned int count) |
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| 209 | { |
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| 210 | unsigned char args[4]; |
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| 211 | unsigned char sdcard_rsp; |
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| 212 | register int i; |
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| 213 | |
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| 214 | for (i = 0; i < 4; i++) |
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[388] | 215 | { |
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[292] | 216 | args[i] = (sdcard->access_pointer >> (32 - (i+1)*8)) & 0xFF; |
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[388] | 217 | } |
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[292] | 218 | |
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| 219 | _sdcard_enable(sdcard); |
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| 220 | |
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| 221 | sdcard_rsp = _sdcard_send_command(sdcard, 17, SDCARD_CMD, args, 0x00); |
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| 222 | if ( SDCARD_CHECK_R1_ERROR(sdcard_rsp) ) |
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| 223 | { |
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| 224 | _sdcard_disable(sdcard); |
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| 225 | return sdcard_rsp; |
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| 226 | } |
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| 227 | |
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| 228 | _sdcard_wait_data_block(sdcard); |
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| 229 | |
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[398] | 230 | spi_get_data(sdcard->spi, buf, count); |
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[292] | 231 | |
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| 232 | /* |
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| 233 | * Get the remainder of the block bytes and the CRC16 (comes |
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| 234 | * at the end of the data block) |
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| 235 | */ |
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[398] | 236 | i = count; |
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[292] | 237 | while( i++ < (sdcard->block_length + 2) ) _sdcard_receive_char(sdcard); |
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| 238 | |
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| 239 | _sdcard_disable(sdcard); |
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| 240 | |
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| 241 | /* |
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| 242 | * Move the access pointer to the next block |
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| 243 | */ |
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| 244 | sdcard->access_pointer += sdcard->block_length; |
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| 245 | |
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| 246 | return 0; |
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| 247 | } |
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| 248 | |
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| 249 | unsigned int sdcard_dev_write(struct sdcard_dev *sdcard, void * buf, unsigned int count) |
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| 250 | { |
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| 251 | return 0; |
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| 252 | } |
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| 253 | |
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| 254 | void sdcard_dev_lseek(struct sdcard_dev * sdcard, unsigned int blk_pos) |
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| 255 | { |
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| 256 | sdcard->access_pointer = sdcard->block_length * blk_pos; |
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| 257 | } |
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| 258 | |
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| 259 | unsigned int sdcard_dev_get_capacity(struct sdcard_dev * sdcard) |
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| 260 | { |
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| 261 | return sdcard->capacity; |
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| 262 | } |
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| 263 | |
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| 264 | int sdcard_dev_set_blocklen(struct sdcard_dev * sdcard, unsigned int len) |
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| 265 | { |
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| 266 | unsigned char args[4]; |
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| 267 | unsigned char sdcard_rsp; |
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| 268 | register int i; |
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| 269 | |
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| 270 | for (i = 0; i < 4; i++) |
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| 271 | args[i] = (len >> (32 - (i+1)*8)) & 0xFF; |
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| 272 | |
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| 273 | _sdcard_enable(sdcard); |
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| 274 | |
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| 275 | sdcard_rsp = _sdcard_send_command(sdcard, 16, SDCARD_CMD, args, 0x00); |
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| 276 | if ( SDCARD_CHECK_R1_ERROR(sdcard_rsp) ) |
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| 277 | { |
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| 278 | _sdcard_disable(sdcard); |
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| 279 | return sdcard_rsp; |
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| 280 | } |
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| 281 | |
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| 282 | _sdcard_disable(sdcard); |
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| 283 | |
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| 284 | sdcard->block_length = len; |
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| 285 | |
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| 286 | return 0; |
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| 287 | } |
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| 288 | |
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| 289 | /* |
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| 290 | * vim: tabstop=4 : shiftwidth=4 : expandtab : softtabstop=4 |
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| 291 | */ |
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