pw_kvs/public/pw_kvs/flash_memory.h - pigweed/pigweed - Git at Google

 // Copyright 2020 The Pigweed Authors
 //
 // 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
 //
 //     https://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.
 #pragma once

 #include <cstddef>
 #include <cstdint>
 #include <initializer_list>

 #include "pw_span/span.h"
 #include "pw_status/status.h"
 #include "pw_status/status_with_size.h"

 namespace pw {

 // TODO: These are general-purpose utility functions that should be moved
 //       elsewhere.
 constexpr size_t AlignDown(size_t value, size_t alignment) {
   return (value / alignment) * alignment;
 }

 constexpr size_t AlignUp(size_t value, size_t alignment) {
   return (value + alignment - 1) / alignment * alignment;
 }

 }  // namespace pw

 namespace pw::kvs {

 enum class PartitionPermission : bool {
   kReadOnly,
   kReadAndWrite,
 };

 class FlashMemory {
  public:
   // The flash address is in the range of: 0 to FlashSize.
   typedef uint32_t Address;
   constexpr FlashMemory(size_t sector_size,
                         size_t sector_count,
                         size_t alignment,
                         uint32_t start_address = 0,
                         uint32_t sector_start = 0,
                         std::byte erased_memory_content = std::byte{0xFF})
       : sector_size_(sector_size),
         flash_sector_count_(sector_count),
         alignment_(alignment),
         start_address_(start_address),
         start_sector_(sector_start),
         erased_memory_content_(erased_memory_content) {
     // TODO: The smallest possible alignment is 1 B; 0 is invalid.
     // DCHECK_NE(alignment_, 0);
   }

   virtual ~FlashMemory() = default;

   virtual Status Enable() = 0;
   virtual Status Disable() = 0;
   virtual bool IsEnabled() const = 0;
   virtual Status SelfTest() { return Status::UNIMPLEMENTED; }

   // Erase num_sectors starting at a given address. Blocking call.
   // Address should be on a sector boundary.
   // Returns: OK, on success.
   //          TIMEOUT, on timeout.
   //          INVALID_ARGUMENT, if address or sector count is invalid.
   //          UNKNOWN, on HAL error
   virtual Status Erase(Address flash_address, size_t num_sectors) = 0;

   // Reads bytes from flash into buffer. Blocking call.
   // Returns: OK, on success.
   //          TIMEOUT, on timeout.
   //          INVALID_ARGUMENT, if address or length is invalid.
   //          UNKNOWN, on HAL error
   virtual StatusWithSize Read(Address address, span<std::byte> output) = 0;

   StatusWithSize Read(Address address, void* buffer, size_t len) {
     return Read(address, span(static_cast<std::byte*>(buffer), len));
   }

   // Writes bytes to flash. Blocking call.
   // Returns: OK, on success.
   //          TIMEOUT, on timeout.
   //          INVALID_ARGUMENT, if address or length is invalid.
   //          UNKNOWN, on HAL error
   virtual StatusWithSize Write(Address destination_flash_address,
                                span<const std::byte> data) = 0;

   StatusWithSize Write(Address destination_flash_address,
                        const void* data,
                        size_t len) {
     return Write(destination_flash_address,
                  span(static_cast<const std::byte*>(data), len));
   }

   // Convert an Address to an MCU pointer, this can be used for memory
   // mapped reads. Return NULL if the memory is not memory mapped.
   virtual std::byte* FlashAddressToMcuAddress(Address) const { return nullptr; }

   // start_sector() is useful for FlashMemory instances where the
   // sector start is not 0. (ex.: cases where there are portions of flash
   // that should be handled independently).
   constexpr uint32_t start_sector() const { return start_sector_; }
   constexpr size_t sector_size_bytes() const { return sector_size_; }
   constexpr size_t sector_count() const { return flash_sector_count_; }
   constexpr size_t alignment_bytes() const { return alignment_; }
   constexpr size_t size_bytes() const {
     return sector_size_ * flash_sector_count_;
   }
   // Address of the start of flash (the address of sector 0)
   constexpr uint32_t start_address() const { return start_address_; }
   constexpr std::byte erased_memory_content() const {
     return erased_memory_content_;
   }

  private:
   const uint32_t sector_size_;
   const uint32_t flash_sector_count_;
   const uint8_t alignment_;
   const uint32_t start_address_;
   const uint32_t start_sector_;
   const std::byte erased_memory_content_;
 };

 class FlashPartition {
  public:
   // The flash address is in the range of: 0 to PartitionSize.
   using Address = uint32_t;

   constexpr FlashPartition(
       FlashMemory* flash,
       uint32_t start_sector_index,
       uint32_t sector_count,
       uint32_t alignment_bytes = 0,  // Defaults to flash alignment
       PartitionPermission permission = PartitionPermission::kReadAndWrite)
       : flash_(*flash),
         start_sector_index_(start_sector_index),
         sector_count_(sector_count),
         alignment_bytes_(alignment_bytes == 0 ? flash_.alignment_bytes()
                                               : alignment_bytes),
         permission_(permission) {}

   virtual ~FlashPartition() = default;

   // Performs any required partition or flash-level initialization.
   virtual Status Init() { return Status::OK; }

   // Erase num_sectors starting at a given address. Blocking call.
   // Address should be on a sector boundary.
   // Returns: OK, on success.
   //          TIMEOUT, on timeout.
   //          INVALID_ARGUMENT, if address or sector count is invalid.
   //          PERMISSION_DENIED, if partition is read only.
   //          UNKNOWN, on HAL error
   virtual Status Erase(Address address, size_t num_sectors);

   Status Erase() { return Erase(0, this->sector_count()); }

   // Reads bytes from flash into buffer. Blocking call.
   // Returns: OK, on success.
   //          TIMEOUT, on timeout.
   //          INVALID_ARGUMENT, if address or length is invalid.
   //          UNKNOWN, on HAL error
   virtual StatusWithSize Read(Address address, span<std::byte> output);

   StatusWithSize Read(Address address, size_t length, void* output) {
     return Read(address, span(static_cast<std::byte*>(output), length));
   }

   // Writes bytes to flash. Blocking call.
   // Returns: OK, on success.
   //          TIMEOUT, on timeout.
   //          INVALID_ARGUMENT, if address or length is invalid.
   //          PERMISSION_DENIED, if partition is read only.
   //          UNKNOWN, on HAL error
   virtual StatusWithSize Write(Address address, span<const std::byte> data);

   // Returns the total number of bytes written, including any padding.
   StatusWithSize WriteAligned(
       Address start_address, std::initializer_list<span<const std::byte>> data);

   // Check to see if chunk of flash memory is erased. Address and len need to
   // be aligned with FlashMemory.
   // Returns: OK, on success.
   //          TIMEOUT, on timeout.
   //          INVALID_ARGUMENT, if address or length is invalid.
   //          UNKNOWN, on HAL error
   // TODO: StatusWithBool
   virtual Status IsRegionErased(Address source_flash_address,
                                 size_t len,
                                 bool* is_erased);

   // Overridden by derived classes. The reported sector size is space available
   // to users of FlashPartition. It accounts for space reserved in the sector
   // for FlashPartition to store metadata.
   virtual size_t sector_size_bytes() const {
     return flash_.sector_size_bytes();
   }

   size_t size_bytes() const { return sector_count() * sector_size_bytes(); }

   size_t alignment_bytes() const { return alignment_bytes_; }

   size_t sector_count() const { return sector_count_; }

   // Convert a FlashMemory::Address to an MCU pointer, this can be used for
   // memory mapped reads. Return NULL if the memory is not memory mapped.
   std::byte* PartitionAddressToMcuAddress(Address address) const {
     return flash_.FlashAddressToMcuAddress(PartitionToFlashAddress(address));
   }

   // Converts an address from the partition address space to the flash address
   // space. If the partition reserves additional space in the sector, the flash
   // address space may not be contiguous, and this conversion accounts for that.
   virtual FlashMemory::Address PartitionToFlashAddress(Address address) const {
     return flash_.start_address() +
            (start_sector_index_ - flash_.start_sector()) * sector_size_bytes() +
            address;
   }

   bool writable() const {
     return permission_ == PartitionPermission::kReadAndWrite;
   }

   uint32_t start_sector_index() const { return start_sector_index_; }

  protected:
   Status CheckBounds(Address address, size_t len) const;
   FlashMemory& flash() const { return flash_; }

  private:
   FlashMemory& flash_;
   const uint32_t start_sector_index_;
   const uint32_t sector_count_;
   const uint32_t alignment_bytes_;
   const PartitionPermission permission_;
 };

 }  // namespace pw::kvs
	// Copyright 2020 The Pigweed Authors
	//
	// 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
	//
	// https://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.
	#pragma once

	#include <cstddef>
	#include <cstdint>
	#include <initializer_list>

	#include "pw_span/span.h"
	#include "pw_status/status.h"
	#include "pw_status/status_with_size.h"

	namespace pw {

	// TODO: These are general-purpose utility functions that should be moved
	// elsewhere.
	constexpr size_t AlignDown(size_t value, size_t alignment) {
	return (value / alignment) * alignment;
	}

	constexpr size_t AlignUp(size_t value, size_t alignment) {
	return (value + alignment - 1) / alignment * alignment;
	}

	} // namespace pw

	namespace pw::kvs {

	enum class PartitionPermission : bool {
	kReadOnly,
	kReadAndWrite,
	};

	class FlashMemory {
	public:
	// The flash address is in the range of: 0 to FlashSize.
	typedef uint32_t Address;
	constexpr FlashMemory(size_t sector_size,
	size_t sector_count,
	size_t alignment,
	uint32_t start_address = 0,
	uint32_t sector_start = 0,
	std::byte erased_memory_content = std::byte{0xFF})
	: sector_size_(sector_size),
	flash_sector_count_(sector_count),
	alignment_(alignment),
	start_address_(start_address),
	start_sector_(sector_start),
	erased_memory_content_(erased_memory_content) {
	// TODO: The smallest possible alignment is 1 B; 0 is invalid.
	// DCHECK_NE(alignment_, 0);
	}

	virtual ~FlashMemory() = default;

	virtual Status Enable() = 0;
	virtual Status Disable() = 0;
	virtual bool IsEnabled() const = 0;
	virtual Status SelfTest() { return Status::UNIMPLEMENTED; }

	// Erase num_sectors starting at a given address. Blocking call.
	// Address should be on a sector boundary.
	// Returns: OK, on success.
	// TIMEOUT, on timeout.
	// INVALID_ARGUMENT, if address or sector count is invalid.
	// UNKNOWN, on HAL error
	virtual Status Erase(Address flash_address, size_t num_sectors) = 0;

	// Reads bytes from flash into buffer. Blocking call.
	// Returns: OK, on success.
	// TIMEOUT, on timeout.
	// INVALID_ARGUMENT, if address or length is invalid.
	// UNKNOWN, on HAL error
	virtual StatusWithSize Read(Address address, span<std::byte> output) = 0;

	StatusWithSize Read(Address address, void* buffer, size_t len) {
	return Read(address, span(static_cast<std::byte*>(buffer), len));
	}

	// Writes bytes to flash. Blocking call.
	// Returns: OK, on success.
	// TIMEOUT, on timeout.
	// INVALID_ARGUMENT, if address or length is invalid.
	// UNKNOWN, on HAL error
	virtual StatusWithSize Write(Address destination_flash_address,
	span<const std::byte> data) = 0;

	StatusWithSize Write(Address destination_flash_address,
	const void* data,
	size_t len) {
	return Write(destination_flash_address,
	span(static_cast<const std::byte*>(data), len));
	}

	// Convert an Address to an MCU pointer, this can be used for memory
	// mapped reads. Return NULL if the memory is not memory mapped.
	virtual std::byte* FlashAddressToMcuAddress(Address) const { return nullptr; }

	// start_sector() is useful for FlashMemory instances where the
	// sector start is not 0. (ex.: cases where there are portions of flash
	// that should be handled independently).
	constexpr uint32_t start_sector() const { return start_sector_; }
	constexpr size_t sector_size_bytes() const { return sector_size_; }
	constexpr size_t sector_count() const { return flash_sector_count_; }
	constexpr size_t alignment_bytes() const { return alignment_; }
	constexpr size_t size_bytes() const {
	return sector_size_ * flash_sector_count_;
	}
	// Address of the start of flash (the address of sector 0)
	constexpr uint32_t start_address() const { return start_address_; }
	constexpr std::byte erased_memory_content() const {
	return erased_memory_content_;
	}

	private:
	const uint32_t sector_size_;
	const uint32_t flash_sector_count_;
	const uint8_t alignment_;
	const uint32_t start_address_;
	const uint32_t start_sector_;
	const std::byte erased_memory_content_;
	};

	class FlashPartition {
	public:
	// The flash address is in the range of: 0 to PartitionSize.
	using Address = uint32_t;

	constexpr FlashPartition(
	FlashMemory* flash,
	uint32_t start_sector_index,
	uint32_t sector_count,
	uint32_t alignment_bytes = 0, // Defaults to flash alignment
	PartitionPermission permission = PartitionPermission::kReadAndWrite)
	: flash_(*flash),
	start_sector_index_(start_sector_index),
	sector_count_(sector_count),
	alignment_bytes_(alignment_bytes == 0 ? flash_.alignment_bytes()
	: alignment_bytes),
	permission_(permission) {}

	virtual ~FlashPartition() = default;

	// Performs any required partition or flash-level initialization.
	virtual Status Init() { return Status::OK; }

	// Erase num_sectors starting at a given address. Blocking call.
	// Address should be on a sector boundary.
	// Returns: OK, on success.
	// TIMEOUT, on timeout.
	// INVALID_ARGUMENT, if address or sector count is invalid.
	// PERMISSION_DENIED, if partition is read only.
	// UNKNOWN, on HAL error
	virtual Status Erase(Address address, size_t num_sectors);

	Status Erase() { return Erase(0, this->sector_count()); }

	// Reads bytes from flash into buffer. Blocking call.
	// Returns: OK, on success.
	// TIMEOUT, on timeout.
	// INVALID_ARGUMENT, if address or length is invalid.
	// UNKNOWN, on HAL error
	virtual StatusWithSize Read(Address address, span<std::byte> output);

	StatusWithSize Read(Address address, size_t length, void* output) {
	return Read(address, span(static_cast<std::byte*>(output), length));
	}

	// Writes bytes to flash. Blocking call.
	// Returns: OK, on success.
	// TIMEOUT, on timeout.
	// INVALID_ARGUMENT, if address or length is invalid.
	// PERMISSION_DENIED, if partition is read only.
	// UNKNOWN, on HAL error
	virtual StatusWithSize Write(Address address, span<const std::byte> data);

	// Returns the total number of bytes written, including any padding.
	StatusWithSize WriteAligned(
	Address start_address, std::initializer_list<span<const std::byte>> data);

	// Check to see if chunk of flash memory is erased. Address and len need to
	// be aligned with FlashMemory.
	// Returns: OK, on success.
	// TIMEOUT, on timeout.
	// INVALID_ARGUMENT, if address or length is invalid.
	// UNKNOWN, on HAL error
	// TODO: StatusWithBool
	virtual Status IsRegionErased(Address source_flash_address,
	size_t len,
	bool* is_erased);

	// Overridden by derived classes. The reported sector size is space available
	// to users of FlashPartition. It accounts for space reserved in the sector
	// for FlashPartition to store metadata.
	virtual size_t sector_size_bytes() const {
	return flash_.sector_size_bytes();
	}

	size_t size_bytes() const { return sector_count() * sector_size_bytes(); }

	size_t alignment_bytes() const { return alignment_bytes_; }

	size_t sector_count() const { return sector_count_; }

	// Convert a FlashMemory::Address to an MCU pointer, this can be used for
	// memory mapped reads. Return NULL if the memory is not memory mapped.
	std::byte* PartitionAddressToMcuAddress(Address address) const {
	return flash_.FlashAddressToMcuAddress(PartitionToFlashAddress(address));
	}

	// Converts an address from the partition address space to the flash address
	// space. If the partition reserves additional space in the sector, the flash
	// address space may not be contiguous, and this conversion accounts for that.
	virtual FlashMemory::Address PartitionToFlashAddress(Address address) const {
	return flash_.start_address() +
	(start_sector_index_ - flash_.start_sector()) * sector_size_bytes() +
	address;
	}

	bool writable() const {
	return permission_ == PartitionPermission::kReadAndWrite;
	}

	uint32_t start_sector_index() const { return start_sector_index_; }

	protected:
	Status CheckBounds(Address address, size_t len) const;
	FlashMemory& flash() const { return flash_; }

	private:
	FlashMemory& flash_;
	const uint32_t start_sector_index_;
	const uint32_t sector_count_;
	const uint32_t alignment_bytes_;
	const PartitionPermission permission_;
	};

	} // namespace pw::kvs