bd: Added prototype block device api

Author: geky

features/filesystem/bd/BlockDevice.cpp

@@ -0,0 +1,75 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2017 ARM Limited
+ *
+ * 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 "BlockDevice.h"
+
+
+// Writes by default perform an erase + program
+bd_error_t BlockDevice::write(const void *buffer, bd_addr_t addr, bd_size_t size)
+{
+    if (!is_valid_write(addr, size)) {
+        return BD_ERROR_PARAMETER;
+    }
+
+    bd_error_t err = erase(addr, size);
+    if (err) {
+        return err;
+    }
+
+    return program(buffer, addr, size);
+}
+
+bd_size_t BlockDevice::get_write_size()
+{
+    return get_erase_size();
+}
+
+bool BlockDevice::is_valid_write(bd_addr_t addr, bd_size_t size)
+{
+    return is_valid_erase(addr, size);
+}
+
+
+// Convenience functions for checking block validity
+static bool is_aligned(uint64_t x, uint64_t alignment)
+{
+    return (x / alignment) * alignment == x;
+}
+
+bool BlockDevice::is_valid_read(bd_addr_t addr, bd_size_t size)
+{
+    return (
+        is_aligned(addr, get_read_size()) &&
+        is_aligned(size, get_read_size()) &&
+        addr + size <= this->size());
+}
+
+bool BlockDevice::is_valid_erase(bd_addr_t addr, bd_size_t size)
+{
+    return (
+        is_aligned(addr, get_erase_size()) &&
+        is_aligned(size, get_erase_size()) &&
+        addr + size <= this->size());
+}
+
+bool BlockDevice::is_valid_program(bd_addr_t addr, bd_size_t size)
+{
+    return (
+        is_aligned(addr, get_program_size()) &&
+        is_aligned(size, get_program_size()) &&
+        addr + size <= this->size());
+}
+

features/filesystem/bd/BlockDevice.h

@@ -0,0 +1,186 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2017 ARM Limited
+ *
+ * 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_BLOCK_DEVICE_H
+#define MBED_BLOCK_DEVICE_H
+
+#include <stdint.h>
+
+
+/** Enum of standard error codes
+ *
+ *  @enum bd_error_t
+ */
+enum bd_error {
+    BD_ERROR_OK                 = 0,     /*!< no error */
+    BD_ERROR_WOULD_BLOCK        = -4001, /*!< operation would block */
+    BD_ERROR_UNSUPPORTED        = -4002, /*!< unsupported operation */
+    BD_ERROR_PARAMETER          = -4003, /*!< invalid parameter */
+    BD_ERROR_NO_INIT            = -4004, /*!< uninitialized */
+    BD_ERROR_NO_DEVICE          = -4005, /*!< device is missing or not connected */
+    BD_ERROR_WRITE_PROTECTED    = -4006, /*!< write protected */
+    BD_ERROR_DEVICE_ERROR       = -4007, /*!< device specific error */
+};
+
+/** Type representing either 0 or a negative error code
+ */
+typedef int32_t bd_error_t;
+
+/** Type representing the address of a specific block
+ */
+typedef uint64_t bd_addr_t;
+
+/** Type representing a quantity of 8-bit bytes
+ */
+typedef uint64_t bd_size_t;
+
+
+/** A hardware device capable of writing and reading blocks
+ */
+class BlockDevice {
+public:
+    /** Lifetime of a block device
+     */
+    virtual ~BlockDevice() {};
+
+    /** Initialize a block device
+     *
+     *  @return         0 on success or a negative error code on failure
+     */
+    virtual bd_error_t init() = 0;
+
+    /** Deinitialize a block device
+     *
+     *  @return         0 on success or a negative error code on failure
+     */
+    virtual bd_error_t deinit() = 0;
+
+    /** Read blocks from a block device
+     *
+     *  If a failure occurs, it is not possible to determine how many bytes succeeded
+     *
+     *  @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) = 0;
+
+    /** Write blocks to a block device
+     *
+     *  A write is equivalent to an erase followed by a program
+     *
+     *  If a failure occurs, it is not possible to determine how many bytes succeeded
+     *
+     *  @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 write block size
+     *  @return         0 on success, negative error code on failure
+     */
+    virtual bd_error_t write(const 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
+     *
+     *  If a failure occurs, it is not possible to determine how many bytes succeeded
+     *
+     *  @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) = 0;
+
+    /** 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) = 0;
+
+    /** Get the size of a readable block
+     *
+     *  @return         Size of a readable block in bytes
+     */
+    virtual bd_size_t get_read_size() = 0;
+
+    /** Get the size of a writeable block
+     *
+     *  @return         Size of a writeable block in bytes
+     *  @note Must be a multiple of the read size, this is
+     *  equivalent to the erase size of the device
+     */
+    virtual bd_size_t get_write_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() = 0;
+
+    /** 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() = 0;
+
+    /** Get the total size of the underlying device
+     *
+     *  @return         Size of the underlying device in bytes
+     */
+    virtual bd_size_t size() = 0;
+
+    /** Convenience function for checking block read validity
+     *
+     *  @param addr     Address of block to begin reading from
+     *  @param size     Size to read in bytes
+     *  @return         True if read is valid for underlying block device
+     */
+    bool is_valid_read(bd_addr_t addr, bd_size_t size);
+
+    /** Convenience function for checking block write validity
+     *
+     *  @param addr     Address of block to begin writing to
+     *  @param size     Size to write in bytes
+     *  @return         True if write is valid for underlying block device
+     */
+    bool is_valid_write(bd_addr_t addr, bd_size_t size);
+
+    /** Convenience function for checking block program validity
+     *
+     *  @param addr     Address of block to begin writing to
+     *  @param size     Size to write in bytes
+     *  @return         True if program is valid for underlying block device
+     */
+    bool is_valid_program(bd_addr_t addr, bd_size_t size);
+
+    /** Convenience function for checking block erase validity
+     *
+     *  @param addr     Address of block to begin erasing
+     *  @param size     Size to erase in bytes
+     *  @return         True if erase is valid for underlying block device
+     */
+    bool is_valid_erase(bd_addr_t addr, bd_size_t size);
+};
+
+
+#endif