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// 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.
#include "pw_kvs/flash_memory.h"
#include <algorithm>
#include <cinttypes>
#include <cstring>
#include "pw_kvs_private/macros.h"
#include "pw_log/log.h"
namespace pw::kvs {
using std::byte;
Status FlashPartition::Erase(Address address, size_t num_sectors) {
if (permission_ == PartitionPermission::kReadOnly) {
return Status::PERMISSION_DENIED;
}
TRY(CheckBounds(address, num_sectors * sector_size_bytes()));
return flash_.Erase(PartitionToFlashAddress(address), num_sectors);
}
StatusWithSize FlashPartition::Read(Address address, span<byte> output) {
TRY(CheckBounds(address, output.size()));
return flash_.Read(PartitionToFlashAddress(address), output);
}
StatusWithSize FlashPartition::Write(Address address, span<const byte> data) {
if (permission_ == PartitionPermission::kReadOnly) {
return Status::PERMISSION_DENIED;
}
TRY(CheckBounds(address, data.size()));
return flash_.Write(PartitionToFlashAddress(address), data);
}
StatusWithSize FlashPartition::Write(
const Address start_address, std::initializer_list<span<const byte>> data) {
byte buffer[64]; // TODO: Configure this?
Address address = start_address;
auto bytes_written = [&]() { return address - start_address; };
const size_t write_size = AlignDown(sizeof(buffer), alignment_bytes());
size_t bytes_in_buffer = 0;
for (span<const byte> chunk : data) {
while (!chunk.empty()) {
const size_t to_copy =
std::min(write_size - bytes_in_buffer, chunk.size());
std::memcpy(&buffer[bytes_in_buffer], chunk.data(), to_copy);
chunk = chunk.subspan(to_copy);
bytes_in_buffer += to_copy;
// If the buffer is full, write it out.
if (bytes_in_buffer == write_size) {
Status status = Write(address, span(buffer, write_size));
if (!status.ok()) {
return StatusWithSize(status, bytes_written());
}
address += write_size;
bytes_in_buffer = 0;
}
}
}
// If data remains in the buffer, pad it to the alignment size and flush
// the remaining data.
if (bytes_in_buffer != 0u) {
size_t remaining_write_size = AlignUp(bytes_in_buffer, alignment_bytes());
std::memset(
&buffer[bytes_in_buffer], 0, remaining_write_size - bytes_in_buffer);
if (Status status = Write(address, span(buffer, remaining_write_size));
!status.ok()) {
return StatusWithSize(status, bytes_written());
}
address += remaining_write_size;
}
return StatusWithSize(bytes_written());
}
Status FlashPartition::IsRegionErased(Address source_flash_address,
size_t length,
bool* is_erased) {
// Max alignment is artificial to keep the stack usage low for this
// function. Using 16 because it's the alignment of encrypted flash.
constexpr size_t kMaxAlignment = 16;
// Relying on Read() to check address and len arguments.
if (is_erased == nullptr) {
return Status::INVALID_ARGUMENT;
}
const size_t alignment = alignment_bytes();
if (alignment > kMaxAlignment || kMaxAlignment % alignment ||
length % alignment) {
return Status::INVALID_ARGUMENT;
}
byte buffer[kMaxAlignment];
byte erased_pattern_buffer[kMaxAlignment];
size_t offset = 0;
std::memset(erased_pattern_buffer,
int(flash_.erased_memory_content()),
sizeof(erased_pattern_buffer));
*is_erased = false;
while (length > 0u) {
// Check earlier that length is aligned, no need to round up
size_t read_size = std::min(sizeof(buffer), length);
TRY(Read(source_flash_address + offset, read_size, buffer).status());
if (std::memcmp(buffer, erased_pattern_buffer, read_size)) {
// Detected memory chunk is not entirely erased
return Status::OK;
}
offset += read_size;
length -= read_size;
}
*is_erased = true;
return Status::OK;
}
Status FlashPartition::CheckBounds(Address address, size_t length) const {
if (address + length > size_bytes()) {
PW_LOG_ERROR("Attempted out-of-bound flash memory access (address: %" PRIu32
" length: %zu)",
address,
length);
return Status::OUT_OF_RANGE;
}
return Status::OK;
}
} // namespace pw::kvs
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