ktrofimov
commented
2 years ago Not recovering form DMA RBU error under debug could be a separate issue: https://lists.gnu.org/archive/html/lwip-users/2012-09/msg00045.html
Solution provided (for the old STM32F4 driver) has a continued read in cycle while(p=low_level_input()) (same as in the new driver) and the same DMA reset code ETH->DMASR = ETH_DMASR_RBUS; and ETH->DMARPDR = 0;:
/**
* Should allocate a pbuf and transfer the bytes of the incoming
* packet from the interface into the pbuf.
*
* @param netif the lwip network interface structure for this ethernetif
* @return a pbuf filled with the received packet (including MAC header)
* NULL on memory error
*/
static struct pbuf * low_level_input(struct netif *netif)
{
struct pbuf *p, *q;
u16_t len;
uint32_t l=0,i =0;
FrameTypeDef frame;
u8 *buffer;
__IO ETH_DMADESCTypeDef *DMARxNextDesc;
p = NULL;
/* Get received frame */
frame = ETH_Get_Received_Frame_interrupt();
if (frame.descriptor && frame.buffer) {
/* check that frame has no error */
if ((frame.descriptor->Status & ETH_DMARxDesc_ES) == (uint32_t)RESET)
{
/* Obtain the size of the packet and put it into the "len" variable. */
len = frame.length;
buffer = (u8 *)frame.buffer;
/* We allocate a pbuf chain of pbufs from the pool. */
p = pbuf_alloc(PBUF_RAW, len, PBUF_POOL);
/* Copy received frame from ethernet driver buffer to stack buffer */
if (p != NULL)
{
for (q = p; q != NULL; q = q->next)
{
memcpy((u8_t*)q->payload, (u8_t*)&buffer[l], q->len);
l = l + q->len;
}
}
}
/* Release descriptors to DMA */
/* Check if received frame with multiple DMA buffer segments */
if (DMA_RX_FRAME_infos->Seg_Count > 1)
{
DMARxNextDesc = DMA_RX_FRAME_infos->FS_Rx_Desc;
}
else
{
DMARxNextDesc = frame.descriptor;
}
/* Set Own bit in Rx descriptors: gives the buffers back to DMA */
for (i=0; i<DMA_RX_FRAME_infos->Seg_Count; i++)
{
DMARxNextDesc->Status = ETH_DMARxDesc_OWN;
DMARxNextDesc = (ETH_DMADESCTypeDef *)(DMARxNextDesc->Buffer2NextDescAddr);
}
/* Clear Segment_Count */
DMA_RX_FRAME_infos->Seg_Count =0;
}
return p;
}
static void ethernet_watchdog(void) {
/* When Rx Buffer unavailable flag is set: clear it and resume reception */
if ((ETH->DMASR & ETH_DMASR_RBUS) != (u32)RESET)
{
/* Clear RBUS ETHERNET DMA flag */
ETH->DMASR = ETH_DMASR_RBUS;
/* Resume DMA reception. The register doesn't care what you write to it. */
ETH->DMARPDR = 0;
}
}
void ethernetif_input( void * pvParameters )
{
struct pbuf *p;
for( ;; )
{
if (xSemaphoreTake( s_xSemaphore, emacBLOCK_TIME_WAITING_FOR_INPUT)==pdTRUE)
{
while ((p = low_level_input( s_pxNetIf )) != 0) {
if (p != 0) {
if (ERR_OK != s_pxNetIf->input( p, s_pxNetIf))
{
pbuf_free(p);
p=NULL;
}
}
}
}
ethernet_watchdog();
}
} 
dima-kapustin
ASELSTM
Custom board with STM32H734IIT6 MCU, STM32CubeIDE Version: 1.9.0, Build: 12015_20220302_0855 Compiler: GNU Tools for STM32 (9-2020-q2-update)
After reading documents about how to run Ethernet on H7 series I am able to have my Ethernet working, but now I do facing an issue I can't solve. Stack can work for some time, but suddenly board stops sending data. Error callback is fired:
This happens on custom project board, when everything usually works fine for weeks, but sometimes it just stopped all ethernet activity. I was unable to find a real source of trouble and decided to upgrade HAL Ethernet driver to the latest version from these STM github.com sources. One line of code I had to add: in low_level_output, right before pbuf_ref(p) I have to call SCB_CleanInvalidateDCache(). Otherwise there was no ethernet activity. With these new drivers my project is running as it was before, with the old drivers.
After I did make sure that all this works I begin a stress-test. Board has some background activity (Wireguard link with keep-alive data, https (MBedTLS) client connection with data store to the central database and Chrome browser tab reloading JSON data from MCU once in 5 seconds). Additional load is:
With such load (not a big one) MCU works for about 5 minutes as expected. Wireshark shows no problems or missed packets at all. But suddenly all transmission stops. See attaches screenshot:
192.168.2.1 is my notebook 192.168.2.9 is a controller Last packet from MCU is #24948 Capture file: Failure at packet 24948.pcapng.zip
I have found similar problems on ST forum (https://community.st.com/s/question/0D53W00001PyCiISAV/ethdmacsrrbu-error-occurs-and-stalls-the-ethernet-receive-on-stm32h7is-there-a-way-around-this-issue-with-the-dma?t=1655188070920 and https://community.st.com/s/question/0D53W00001EjVIqSAN/im-working-on-h743-sometimes-i-find-ethdmacsrrbu-errorhow-to-solve-ethdmacsrrbu-issue) but there is no solution.
Some people says that
heth->Instance->DMACSR = ETH_DMACSR_RBU;andheth->Instance->DMACRDTPR = 0;helps them, but in my case it doesn't.Is it possible to restart DMA, even loosing current data referenced in descriptors?