stm32f769 OTG DMA HS peripheral mode locks up on input xfer > 1KB

TCoop.1 · ‎2020-03-10

I have an STM32F769NI discovery board. I am using USB in HS mode, OTG, in peripheral mode, CDC class. The goal is to move > 10MB/sec to a host while having enough time to concurrently bring in about that same amount of data over two SPI interfaces. Packet size is 512; transfer size wants to be as large as possible (64KB or more if possible). All works fine in non-dma mode (except for the data rate). When OTG DMA is enabled, transfers greater than 1024 bytes do not complete. Specifically, they are started, but (1) there is no xfer complete interrupt; (2) the size register is nonzero, indicating more data to be transferred, (3) the DMA register for the endpoint appears to show the original start address + the full length of the transfer (rounded up to the next longword boundary), and (4) no interrupts are pending. With non-DMA access, arbitrary lengths work fine (up to 16KB tested). The behavior and stopping point are the same whether the host is a Linux desktop through a USB hub or directly connected to a windows laptop.

The following log shows a successful 1K transfer, followed by an unsuccessful 1025 byte transfer. After the 1K transfer, I display USB registers of interest, where the DMA address (see the log for the initial values) implies complete but the size register implies another packet is needed.

The log shows xfers from SDRAM, though the behaviour is the same whether the xfer is from SRAM or SDRAM (though SRAM is much faster).

Any guidance would be appreciated. I can obtain more register values or more detailed logging information if needed. Thanks.

Logged Info with 1uS timestamps:

>> Last of several 1K xfers in rapid succession:

00:17.592548: USB xmit: ep129, 0xc0689240, len 1024, dma 1

00:17.592558: EP1 IN xfer size 0x00100400

00:17.592564: EP enable IN 1 CNAK

00:17.592684: IRQ: ep1 in, 00000001 (XFRC)

00:17.592697: USB xmit: ep1, 0x00000000, len 0, dma 1

00:17.592704: EP enable IN 1 CNAK

00:17.592776: IRQ: ep1 in, 00000001 (XFRC)

00:17.592783: CDC_Itf_TxDone ep 1

>> Start of transfer having length 1025. DMA addr 0xc0689240

43:02.274240: USB xmit: ep129, 0xc0689240, len 1025, dma 1

43:02.274250: EP1 IN xfer size 0x00180401

43:02.274256: EP enable IN 1 CNAK

>> no further activity; no xfer complete interrupt

> usbr (USB reg dump)

USB Registers:

000 GOTGTCL ctl and status 0x030d0000

004 GOTGINT interrupt reg 0x00100000

008 GAHBCFG ahb cfg reg 0x0000002b

00c GUSBCFG usb cfg reg 0x40002410

010 GRSTCTL reset reg 0x80000400

014 GINTSTS core int reg 0x04c08428

018 GINTMSK int mask reg 0xc03c3804

01c GRXSTSR rx stat/debug 0x01e60001

024 GRXFSIZ rx FIFO size 0x00000200

038 GCCFG gen core cfg 0x00200000

03c CID core ID reg 0x00002100

Device Regs

800 DCFG device cfg 0x08200770

804 DCTL device ctl 0x00000000

808 DSTS device status 0x00283100

810 DIEPMSK in endpt int msk 0x0000000b

814 DOEPMSK out endpt int msk 0x0000202b

818 DAINT all endpt int 0x00000000

81c DAINTMSK all endpt int msk 0x00030007

834 DIEPEMPM in ep FIFO mpty 0x00000000

838 DEACHINT each ep int reg 0x00000000

83c ..MSK each ep int msk 0x00000000

EP0: In Out

DxEPCTL 0x00208000 0x80028000

DxEPINT 0x000020d0 0x00000050

DxEPTSIZ 0x00000000 0x60080018

DxEPDMA 0x20202020 0x2000dd5c

DTXFSTS 0x00000080 0x0000017u

EP1: In Out

DxEPCTL 0x80488200 0x80098200

DxEPINT 0x00002090 0x00000000

DxEPTSIZ 0x00080000 0x00080200 << size suggests 1 more packet

DxEPDMA 0xc0689644 0x2000a5a0 << DMA addr -> end of xfer

DTXFSTS 0x00000174 0x00000080

DIEPTXFs 0x01740280 << tx fifo size looks correct

EP2: In Out

DxEPCTL 0x008c8008 0x00000000

DxEPINT 0x00002010 0x00000000

DxEPTSIZ 0x00000000 0x00000000

DxEPDMA 0x20202020 0xb24e7820

DTXFSTS 0x00000000 0x00000080

DIEPTXFs 0x00000000

EP3: not active

EP4: not active

EP5: not active

EP6: not active

EP7: not active

EP8: not active