SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
Two DMA management modes can be used to load data from memory to the internal buffer of the controller (or vice versa). These modes are exclusive and depend on the module integration.
DMA master mode is selected by setting the MMCHS_CON[20] DMA_MNS bit to 1. In this case, the controller has direct access to data using a specific algorithm called ADMA2 (prevents the system from being interrupted). Data are exchanged using the L3_MAIN master interface, which supports burst accesses to maximize throughput.
This mode is supported only by modules connected to the L3_MAIN interconnect. For more information and/or to check the value of the MMCHS_HL_HWINFO[0] MADMA_EN bit, see Section 25.1, eMMC/SD/SDIO Overview.
This mode is available for modules MMC1 and MMC2.
DMA slave mode is selected by setting the MMCHS_CON[20] DMA_MNS bit to 0. In this case, the controller is slave on the DMA transaction managed by two separated requests (MMCi_DMA_TX and MMCi_DMA_RX).
This mode is the only mode supported by modules that are not connected to the L3_MAIN interconnect (regardless of the value of the MMCHS_CON[20] DMA_MNS bit). For more information and/or to check the value of the MMCHS_HL_HWINFO[0] MADMA_EN bit, see Section 25.1, eMMC/SD/SDIO Overview.
This mode is available for all MMC modules.