storage: Add the I2C EEPROM block device

features/filesystem/i2cee/I2CEEBlockDevice.cpp

@@ -0,0 +1,135 @@
+/* Simple access class for I2C EEPROM chips like Microchip 24LC
+ * Copyright (c) 2015 Robin Hourahane
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include "I2CEEBlockDevice.h"
+
+#define I2CEE_TIMEOUT 10000
+
+
+I2CEEBlockDevice::I2CEEBlockDevice(
+        PinName sda, PinName scl, uint8_t addr,
+        bd_size_t size, bd_size_t block, int freq)
+    : _i2c(sda, scl), _i2c_addr(addr), _size(size), _block(block)
+{
+    _i2c.frequency(freq);
+}
+
+bd_error_t I2CEEBlockDevice::init()
+{
+    return _sync();
+}
+
+bd_error_t I2CEEBlockDevice::deinit()
+{
+    return 0;
+}
+
+bd_error_t I2CEEBlockDevice::read(void *buffer, bd_addr_t addr, bd_size_t size)
+{
+    // Check the address and size fit onto the chip.
+    if (!is_valid_read(addr, size)) {
+        return BD_ERROR_PARAMETER;
+    }
+
+    _i2c.start();
+    if (!_i2c.write(_i2c_addr | 0) ||
+        !_i2c.write((char)(addr >> 8)) ||
+        !_i2c.write((char)(addr & 0xff))) {
+        return BD_ERROR_DEVICE_ERROR;
+    }
+    _i2c.stop();
+
+    if (_i2c.read(_i2c_addr, static_cast<char*>(buffer), size) < 0) {
+        return BD_ERROR_DEVICE_ERROR;
+    }
+
+    return 0;
+}
+
+bd_error_t I2CEEBlockDevice::program(const void *buffer, bd_addr_t addr, bd_size_t size)
+{
+    // Check the addr and size fit onto the chip.
+    if (!is_valid_program(addr, size)) {
+        return BD_ERROR_PARAMETER;
+    }
+
+    // While we have some more data to write.
+    while (size > 0) {
+        _i2c.start();
+        if (!_i2c.write(_i2c_addr | 0) ||
+            !_i2c.write((char)(addr >> 8)) ||
+            !_i2c.write((char)(addr & 0xff))) {
+            return BD_ERROR_DEVICE_ERROR;
+        }
+
+        for (unsigned i = 0; i < _block; i++) {
+            _i2c.write(static_cast<const char*>(buffer)[i]);
+        }
+        _i2c.stop();
+
+        bd_error_t err = _sync();
+        if (err) {
+            return err;
+        }
+
+        addr += _block;
+        size -= _block;
+        buffer = static_cast<const char*>(buffer) + _block;
+    }
+
+    return 0;
+}
+
+bd_error_t I2CEEBlockDevice::erase(bd_addr_t addr, bd_size_t size)
+{
+    // No erase needed
+    return 0;
+}
+
+bd_error_t I2CEEBlockDevice::_sync()
+{
+    // The chip doesn't ACK while writing to the actual EEPROM
+    // so loop trying to do a zero byte write until it is ACKed
+    // by the chip.
+    for (int i = 0; i < I2CEE_TIMEOUT; i++) {
+        if (_i2c.write(_i2c_addr | 0, 0, 0) < 1) {
+            return 0;
+        }
+
+        wait_ms(1);
+    }
+
+    return BD_ERROR_DEVICE_ERROR;
+}
+
+bd_size_t I2CEEBlockDevice::get_read_size()
+{
+    return 1;
+}
+
+bd_size_t I2CEEBlockDevice::get_program_size()
+{
+    return _block;
+}
+
+bd_size_t I2CEEBlockDevice::get_erase_size()
+{
+    return _block;
+}
+
+bd_size_t I2CEEBlockDevice::size()
+{
+    return _size;
+}

features/filesystem/i2cee/I2CEEBlockDevice.h

@@ -0,0 +1,149 @@
+/* Simple access class for I2C EEPROM chips like Microchip 24LC
+ * Copyright (c) 2015 Robin Hourahane
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef MBED_I2CEEPROM_BLOCK_DEVICE_H
+#define MBED_I2CEEPROM_BLOCK_DEVICE_H
+
+/* If the target has no I2C support then I2CEEPROM is not supported */
+#ifdef DEVICE_I2C
+
+#include <mbed.h>
+#include "BlockDevice.h"
+
+
+/** BlockDevice for I2C based flash device such as
+ *  Microchip's 24LC or ATMEL's AT24C ranges
+ *
+ *  @code
+ *  #include "mbed.h"
+ *  #include "I2CEEBlockDevice.h"
+ *
+ *  // Create 24LC device with 32Kbytes of memory 
+ *  I2CEEBlockDevice flash(D14, D15, 0xa0, 32*1024);
+ *
+ *  int main() {
+ *      printf("flash test\n");
+ *      mx52r.init();
+ *      printf("flash size: %llu\n", flash.size());
+ *      printf("flash read size: %llu\n", flash.get_read_size());
+ *      printf("flash program size: %llu\n", flash.get_program_size());
+ *      printf("flash erase size: %llu\n", flash.get_erase_size());
+ *
+ *      uint8_t *buffer = malloc(flash.get_erase_size());
+ *      sprintf(buffer, "Hello World!\n");
+ *      flash.erase(0, flash.get_erase_size());
+ *      flash.write(buffer, 0, flash.get_erase_size());
+ *      flash.read(buffer, 0, flash.get_erase_size());
+ *      printf("%s", buffer);
+ *
+ *      flash.deinit();
+ *  }
+ */
+class I2CEEBlockDevice : public BlockDevice {
+public:
+    /** Constructor to create an I2CEEBlockDevice on I2C pins
+     *
+     *  @param sda      The pin name for the sda line of the I2C bus.
+     *  @param scl      The pin name for the scl line of the I2C bus.
+     *  @param addr     The 8bit I2C address of the chip, common range 0xa0 - 0xae.
+     *  @param size     The size of the device in bytes
+     *  @param block    The block size of the device in bytes, defaults to 32bytes
+     *  @param freq     The frequency of the I2C bus, defaults to 400K.
+     */
+    I2CEEBlockDevice(
+            PinName sda, PinName scl, uint8_t address,
+            bd_size_t size, bd_size_t block=32,
+            int bus_speed=400000);
+
+    /** Initialize a block device
+     *
+     *  @return         0 on success or a negative error code on failure
+     */
+    virtual bd_error_t init();
+
+    /** Deinitialize a block device
+     *
+     *  @return         0 on success or a negative error code on failure
+     */
+    virtual bd_error_t deinit();
+
+    /** Read blocks from a block device
+     *
+     *  @param buffer   Buffer to write blocks to
+     *  @param addr     Address of block to begin reading from
+     *  @param size     Size to read in bytes, must be a multiple of read block size
+     *  @return         0 on success, negative error code on failure
+     */
+    virtual bd_error_t read(void *buffer, bd_addr_t addr, bd_size_t size);
+
+    /** Program blocks to a block device
+     *
+     *  The blocks must have been erased prior to being programmed
+     *
+     *  @param buffer   Buffer of data to write to blocks
+     *  @param addr     Address of block to begin writing to
+     *  @param size     Size to write in bytes, must be a multiple of program block size
+     *  @return         0 on success, negative error code on failure
+     */
+    virtual bd_error_t program(const void *buffer, bd_addr_t addr, bd_size_t size);
+
+    /** Erase blocks on a block device
+     *
+     *  The state of an erased block is undefined until it has been programmed
+     *
+     *  @param addr     Address of block to begin erasing
+     *  @param size     Size to erase in bytes, must be a multiple of erase block size
+     *  @return         0 on success, negative error code on failure
+     */
+    virtual bd_error_t erase(bd_addr_t addr, bd_size_t size);
+
+    /** Get the size of a readable block
+     *
+     *  @return         Size of a readable block in bytes
+     */
+    virtual bd_size_t get_read_size();
+
+    /** Get the size of a programable block
+     *
+     *  @return         Size of a programable block in bytes
+     *  @note Must be a multiple of the read size
+     */
+    virtual bd_size_t get_program_size();
+
+    /** Get the size of a eraseable block
+     *
+     *  @return         Size of a eraseable block in bytes
+     *  @note Must be a multiple of the program size
+     */
+    virtual bd_size_t get_erase_size();
+
+    /** Get the total size of the underlying device
+     *
+     *  @return         Size of the underlying device in bytes
+     */
+    virtual bd_size_t size();
+
+private:
+    I2C _i2c;
+    uint8_t _i2c_addr;
+    uint32_t _size;
+    uint32_t _block;
+
+    bd_error_t _sync();
+};
+
+#endif  /* DEVICE_SPI */
+
+#endif  /* MBED_SD_BLOCK_DEVICE_H */