src/devices/nand/drivers/nandpart/aml-bad-block.h

// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef SRC_STORAGE_NAND_DRIVERS_NANDPART_AML_BAD_BLOCK_H_
#define SRC_STORAGE_NAND_DRIVERS_NANDPART_AML_BAD_BLOCK_H_

#include <lib/zircon-internal/thread_annotations.h>
#include <lib/zx/vmar.h>
#include <lib/zx/vmo.h>
#include <stddef.h>
#include <zircon/types.h>

#include <utility>

#include <ddk/metadata/bad-block.h>
#include <fbl/array.h>
#include <fbl/ref_ptr.h>

#include "bad-block.h"

namespace nand {

// Bad block implementation for NAND using Amlogic u-boot style bad block tables.
class AmlBadBlock : public BadBlock {
 public:
  struct OobMetadata {
    // Identifier value.
    uint32_t magic;
    // Number of times the block has been programmed and erased.
    int16_t program_erase_cycles;
    // Iteration of the bad block table. Each time a new one is programmed, this
    // should be incremented. Used to identify the newest copy.
    uint16_t generation;
  };

  static zx_status_t Create(Config config, fbl::RefPtr<BadBlock>* out);

  zx_status_t GetBadBlockList(uint32_t first_block, uint32_t last_block,
                              fbl::Array<uint32_t>* bad_blocks) override;
  zx_status_t MarkBlockBad(uint32_t block) override;

 private:
  friend class fbl::RefPtr<AmlBadBlock>;
  friend class fbl::internal::MakeRefCountedHelper<AmlBadBlock>;

  typedef uint8_t BlockStatus;
  constexpr static BlockStatus kNandBlockGood = 0;
  constexpr static BlockStatus kNandBlockBad = 1;
  constexpr static BlockStatus kNandBlockFactoryBad = 2;

  constexpr static size_t kBlockListMax = 8;

  struct BlockListEntry {
    uint32_t block;
    int16_t program_erase_cycles;
    bool valid;
  };

  AmlBadBlock(zx::vmo data_vmo, zx::vmo oob_vmo, fbl::Array<uint8_t> nand_op, Config config,
              fuchsia_hardware_nand_Info nand_info, BlockStatus* table, uint32_t table_len,
              OobMetadata* oob)
      : BadBlock(std::move(data_vmo), std::move(oob_vmo), std::move(nand_op)),
        config_(config.bad_block_config),
        nand_proto_(config.nand_proto),
        nand_(&nand_proto_),
        nand_info_(nand_info),
        block_entry_(nullptr),
        page_(0),
        generation_(0),
        table_valid_(false),
        oob_(oob),
        bad_block_table_(table),
        bad_block_table_len_(table_len) {}

  ~AmlBadBlock() override {
    zx::vmar::root_self()->unmap(reinterpret_cast<uintptr_t>(oob_), sizeof(OobMetadata));
    zx::vmar::root_self()->unmap(reinterpret_cast<uintptr_t>(bad_block_table_),
                                 bad_block_table_len_);
  }

  // Synchronously erase a block.
  zx_status_t EraseBlock(uint32_t block) TA_REQ(lock_);

  // Synchronously write |num_pages| into NAND.
  zx_status_t WritePages(uint32_t nand_page, uint32_t num_pages) TA_REQ(lock_);

  // Synchronously read |num_pages| from NAND.
  zx_status_t ReadPages(uint32_t nand_page, uint32_t num_pages) TA_REQ(lock_);

  // Looks for a valid block to write BBT to.
  zx_status_t GetNewBlock(void) TA_REQ(lock_);

  // Writes in memory copy of BBT to the device.
  zx_status_t WriteBadBlockTable(bool use_new_block) TA_REQ(lock_);

  // Finds BBT and reads it into memory from NAND.
  zx_status_t FindBadBlockTable(void) TA_REQ(lock_);

  // Top level config.
  const bad_block_config_t config_;
  // Parent nand protocol implementation.
  nand_protocol_t nand_proto_;
  ddk::NandProtocolClient nand_;
  const fuchsia_hardware_nand_Info nand_info_;
  // Information about blocks which store BBT entries.
  BlockListEntry block_list_[kBlockListMax];
  // Block with most recent valid BBT entry.
  BlockListEntry* block_entry_;
  // The first page for the last valid BBT entry in above block.
  uint32_t page_;
  // Generation ID of newest BBT entry.
  uint16_t generation_;
  // Whether the table is valid.
  bool table_valid_;
  // OOB metadata appended to end of table. Backed by oob_vmo.
  OobMetadata* oob_;
  // Copy of latest BBT. Each byte 1:1 maps to a block. Backed by data_vmo.
  BlockStatus* bad_block_table_;
  // Size of bad block table, rounded up to |nand_info_.page_size| multiple.
  uint32_t bad_block_table_len_;
};
}  // namespace nand

#endif  // SRC_STORAGE_NAND_DRIVERS_NANDPART_AML_BAD_BLOCK_H_