UDMA

Table of Contents

• Features Supported
• SysConfig Features
• Features NOT Supported
• Important Usage Guidelines
• Additional Documentation
• Example Usage
• API

The UDMA driver provides API to program the DMA module of the DMSS subsystem to setup and initiate DMA transfers.

Features Supported

• Supports both BCDMA and Packet DMA instances
• Supports all DMA operations from both instances from all the cores in the SOC except M4F core
• UDMA block copy for memory to memory transfer
• PDMA module to initiate transfers to/from PDMA peripherals like UART, McASP, McSPI, ADC, MCAN
• DMA transfer to/from from native PSIL peripherals like CPSW, SA2UL
• Event and interrupt management like DMA completion, channel chaining, interrupt sharing using Interrupt Aggregator (IA)
• Resources management across instances and cores for DMA channels, RX flow, Interrupt Aggregator (IA), Interrupt Routers (IR), Global events, Ring Accelerator (RA)
• Interaction with DMSC RM module via SCICLIENT for all non-RealTime (NRT) configuration

SysConfig Features

Note

It is strongly recommend to use SysConfig where it is available instead of using direct SW API calls. This will help simplify the SW application and also catch common mistakes early in the development cycle.

• Selection of UDMA instances - BCDMA, PKTDMA
• Option to skip default global event registration done as part of Udma_init API
• Option to provide user function for virtual to physical and physical to virtual address translation
• Ability of add and configure BCDMA block copy channels
  • Ability to enable interrupt mode for the channel
  • Ability to specify the number of ring entries for the channel
  • Based on above parameters, the SysConfig generated code does below as part of Drivers_open and Drivers_close functions
    • Channel open/close - the handle can be retrieved by the application using g<User_Config_Name>BlkCopyChHandle global variable
    • Set default channel configuration
    • Allocates required ring memories and pass them to channel configuration
    • Register user specified callback when interrupt mode is enabled

Features NOT Supported

• UDMA driver is not supported for M4F core as the DMSS is present only in the main domain

Important Usage Guidelines

• UDMA driver doesn't manage/allocate the descriptor and RA memory. The caller need to allocate and provide the required memory.
• UDMA driver doesn't use any global variables. All the required object memory like channel, driver instance, event etc should be allocated by the caller

Additional Documentation

• EDMA to UDMA Migration document.
• UDMA to DMSS Migration document.

Example Usage

Include the below file to access the APIs

#include <stdio.h>
#include <drivers/udma.h>

Channel Open Example

    int32_t         retVal;
    Udma_ChHandle   chHandle = (Udma_ChHandle) &gUdmaChObj;
    uint32_t        chType;
    Udma_ChPrms     chPrms;
    Udma_ChTxPrms   txPrms;
    Udma_ChRxPrms   rxPrms;
 
    chType = UDMA_CH_TYPE_TR_BLK_COPY;
    UdmaChPrms_init(&chPrms, chType);
    chPrms.fqRingPrms.ringMem       = &gTxRingMem[0U];
    chPrms.fqRingPrms.elemCnt       = 1;
    chPrms.fqRingPrms.ringMemSize   = chPrms.fqRingPrms.elemCnt * sizeof(uint64_t);
    retVal = Udma_chOpen(drvHandle, chHandle, chType, &chPrms);
    if(UDMA_SOK != retVal)
    {
        printf("[Error] UDMA channel open failed!!\r\n");
    }
 
    /* Config TX channel */
    UdmaChTxPrms_init(&txPrms, chType);
    retVal = Udma_chConfigTx(chHandle, &txPrms);
    if(UDMA_SOK != retVal)
    {
        printf("[Error] UDMA TX channel config failed!!\r\n");
    }
 
    /* Config RX channel - which is implicitly paired to TX channel in
     * block copy mode */
    UdmaChRxPrms_init(&rxPrms, chType);
    retVal = Udma_chConfigRx(chHandle, &rxPrms);
    if(UDMA_SOK != retVal)
    {
        printf("[Error] UDMA RX channel config failed!!\r\n");
    }
 
    /* Channel enable */
    retVal = Udma_chEnable(chHandle);
    if(UDMA_SOK != retVal)
    {
        printf("[Error] UDMA channel enable failed!!\r\n");
    }

Channel Close Example

    int32_t         retVal;
    Udma_ChHandle   chHandle = (Udma_ChHandle) &gUdmaChObj;
 
    retVal = Udma_chDisable(chHandle, UDMA_DEFAULT_CH_DISABLE_TIMEOUT);
    if(UDMA_SOK != retVal)
    {
        printf("[Error] UDMA channel disable failed!!\r\n");
    }
 
    retVal = Udma_chClose(chHandle);
    if(UDMA_SOK != retVal)
    {
        printf("[Error] UDMA channel close failed!!\r\n");
    }
 

API

APIs for UDMA