Bootrom NAND Flash Geometry Detection via ECC Lookup
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Solution Overview
Problem
Conventional bootrom devices are limited in their ability to read data from NAND flash memory devices without knowing the manufacturer or device ID, restricting their compatibility with various NAND memory devices and hindering the use of future-developed devices.
Innovation Solution
The implementation of bootrom software that uses a lookup table containing physical geometry/layout information for all supported geometries, allowing it to assume and verify the layout of NAND memory devices without prior knowledge, enabling access to data using error correction codes to determine the correct layout.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If bootrom devices use conventional reading methods requiring prior knowledge of manufacturer or device ID, then reading accuracy is improved, but device compatibility deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing expected ECC values for multiple possible physical geometries in a lookup table during bootrom initialization. This allows the system to quickly verify which geometry matches the actual NAND device without needing prior knowledge of the device ID or manufacturer, thus maintaining reading accuracy while improving compatibility.
Solution Approach 2:
The patent changes the parameter verification approach from relying on device ID/manufacturer information to using ECC validation based on assumed physical geometries. By iterating through different geometry assumptions and verifying them against stored ECC values, the system adapts to different NAND devices without requiring predefined device identification, resolving the contradiction between reading accuracy and device compatibility.
2Adaptability or versatility
If bootrom software is updated to support new NAND devices, then device compatibility is improved, but hardware complexity increases
Solution Approach 1:
The patent segments the geometry information into discrete, predefined physical geometry types with associated ECC parameters stored in a lookup table. Each geometry type represents a distinct segment that can be independently verified. This segmentation allows the bootrom to support multiple NAND device geometries without creating a monolithic complex system, as each geometry can be handled as a separate, manageable unit.
Solution Approach 2:
The system applies self-service by automatically determining the correct physical geometry of the NAND device through ECC validation without requiring external configuration or manual intervention. The bootrom independently iterates through assumed geometries, validates them against the lookup table, and selects the correct one, eliminating the need for complex update procedures or external device identification mechanisms.
3Reliability
If error correction codes are used to verify data integrity, then data reliability is improved, but processing time increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating ECC values for all possible physical geometries during bootrom initialization and storing them in a lookup table. This preliminary preparation eliminates the need for time-consuming ECC calculations during the actual device detection phase, as the system only needs to perform simple comparisons between measured ECC values and pre-computed values, thus maintaining data reliability while minimizing processing time.
Data Source
AI summary
A disclosed apparatus to access a nonvolatile memory includes a physical geometry selector to select a first assumed physical geometry of a nonvolatile memory from among a plurality of assumed physical geometries supported by a memory controller, an information supplier to supply information about the first physical geometry to a set of registers, and a boot up controller to cause the memory controller to access data in the nonvolatile memory. The memory controller to access data in the nonvolatile memory uses the information supplied to the set of registers. Example disclosed apparatus further include a feedback input to receive feedback from the memory controller.