Method and apparatus for performing data access control for host device

A controller of a data access device, the data access device arranged to perform data access control for a host device, the controller comprising:

• a processing circuit, arranged to control the controller according to a plurality of host commands from the host device, to allow the host device to access at least one medium, which is non-transitory, through the controller;
• a transmission interface circuit, arranged to perform communications with the host device;
• and
• a low-density parity-check (LDPC) code decoding circuit, arranged to perform LDPC code decoding;
• wherein:
• the controller receives the plurality of host commands from the host device through the transmission interface circuit within the controller, for performing data access upon the at least one medium according to the plurality of host commands, wherein the data access comprises data receiving;
• and
• the controller performs a data access optimization procedure for maintaining correctness of the data receiving, wherein the data access optimization procedure comprises:
• performing the data receiving upon the at least one medium to obtain at least one code word, wherein the at least one code word comprises multiple column segments;
• in a first decoding phase, utilizing the LDPC code decoding circuit to perform multiple first LDPC code decoding operations regarding the multiple column segments, wherein a portion of column segments among the multiple column segments are abnormal column segments corresponding to puncture variable nodes;
• in a second decoding phase, utilizing the LDPC code decoding circuit to find at least one column segment satisfying at least one predetermined selection condition, to perform at least one second LDPC code decoding operation regarding the at least one column segment;
• in a third decoding phase, utilizing the LDPC code decoding circuit to perform multiple third LDPC code decoding operations regarding the multiple column segments;
• and
• after a plurality of LDPC code decoding operations of the first decoding phase, the second decoding phase, and the third decoding phase, the plurality of LDPC code decoding operations comprising the multiple first LDPC code decoding operations, the at least one second LDPC code decoding operation, and the multiple third LDPC code decoding operations, is completed, returning error-free data corresponding to the at least one code word to the host device.