From dffc57135846a4b00aca06b2f588daa6d13b67ef Mon Sep 17 00:00:00 2001 From: Ha Thach Date: Thu, 11 Jun 2026 10:17:28 +0700 Subject: Fix stm32f723disco host/cdc_msc_hid HIL: UART RX starvation + DWC2 DMA split-IN NAK storm (#3677) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Fix stm32f723disco host HIL: UART RX starvation + DWC2 split bulk NAK/XactErr handling (#3677) stm32f7 BSP — UART RX starvation - The host console USART shared interrupt priority with the USB OTG ISR, so a long OTG interrupt could starve RXNE and drop received bytes. Raise the USART RX IRQ above OTG_FS/OTG_HS in both the bare-metal and FreeRTOS init paths, guarded by #ifdef UART_ID so boards without a UART console keep the default OTG priority. dwc2 host — split NAK/XactErr handling - Slave mode: a persistently-NAKing split bulk/control IN poll re-armed the start-split immediately, storming the ISR and starving task context. Throttle by disabling the channel and re-arming on the resulting halt (no frame deferral). - Buffer-DMA mode: a pure split bulk-OUT NAK was unhandled, leaving the channel halted and stalling the transfer — the dominant cause of CDC echo truncation. Handle it by rewinding the buffer pointers and retrying the start-split (Programming Guide v4.20a 5.1.4.2). - Buffer-DMA mode: a split bulk-OUT XactErr was retried immediately, exhausting HCD_XFER_ERROR_MAX before the transient cleared. Throttle via channel_disable + re-arm to give the hub TT a recovery gap, mirroring slave mode. - All three are scoped to split transfers (hcsplt.split_en); non-split NAK/XactErr keep the core-handled / immediate-retry behavior. The OUT XactErr throttle also excludes periodic split, where channel_disable() is a no-op and would wedge the channel. The nak_disabled flag is generalized to retry_disabled and honors xfer->closing so an endpoint close during a throttled retry tears down cleanly. Verified on stm32f723disco HIL (slave + CFG_TUH_DWC2_DMA_ENABLE): host/cdc_msc_hid, msc_file_explorer, and device_info all pass on both variants; DMA CDC echo went from ~15-25% raw failure to 10/10 clean. --- src/portable/synopsys/dwc2/hcd_dwc2.c | 51 +++++++++++++++++++++++++++++++---- 1 file changed, 46 insertions(+), 5 deletions(-) (limited to 'src') diff --git a/src/portable/synopsys/dwc2/hcd_dwc2.c b/src/portable/synopsys/dwc2/hcd_dwc2.c index 9ea5f33c5..84a0c6afd 100644 --- a/src/portable/synopsys/dwc2/hcd_dwc2.c +++ b/src/portable/synopsys/dwc2/hcd_dwc2.c @@ -104,6 +104,7 @@ typedef struct { uint16_t xferred_bytes; // bytes that accumulate transferred though USB bus for the whole hcd_edpt_xfer(), which can // be composed of multiple channel_xfer_start() (retry with NAK/NYET) uint16_t fifo_bytes; // bytes written/read from/to FIFO (may not be transferred on USB bus). + uint8_t retry_disabled; // 1: channel was disabled to throttle a split retry (NAK in / XactErr out); re-arm on its halt } hcd_xfer_t; typedef struct { @@ -1137,7 +1138,16 @@ static bool handle_channel_in_dma(dwc2_regs_t* dwc2, uint8_t ch_id, uint32_t hci // TU_LOG1("in hcint = %02lX\r\n", hcint); if (hcint & HCINT_HALTED) { - if (hcint & (HCINT_XFER_COMPLETE | HCINT_STALL | HCINT_BABBLE_ERR)) { + if (xfer->retry_disabled) { + // Halt from our split-NAK throttle disable (below): re-arm the start-split, or let teardown finish + // if the endpoint is closing. Programming Guide 3.5 "Halting a Channel" (p73). + xfer->retry_disabled = 0; + if (xfer->closing) { + is_done = true; + } else { + channel_send_in_token(dwc2, channel); + } + } else if (hcint & (HCINT_XFER_COMPLETE | HCINT_STALL | HCINT_BABBLE_ERR)) { const uint16_t remain_bytes = (uint16_t) hctsiz.xfer_size; const uint16_t remain_packets = hctsiz.packet_count; const uint16_t actual_len = edpt->buflen - remain_bytes; @@ -1203,7 +1213,15 @@ static bool handle_channel_in_dma(dwc2_regs_t* dwc2, uint8_t ch_id, uint32_t hci channel->hcintmsk &= ~(HCINT_NAK | HCINT_DATATOGGLE_ERR); hcsplt.split_compl = 0; // restart with start-split channel->hcsplt = hcsplt.value; - channel_xfer_in_retry(dwc2, ch_id, hcint); + // Persistent split bulk/control IN NAK (e.g. idle polled endpoint): re-enabling immediately storms + // the ISR and starves the task. Disable + re-arm on the resulting halt to throttle (like the slave + // path); no frame deferral. Programming Guide 3.5 (p73) Note permits disable on NAK/FrmOvrn splits. + if ((hcint & HCINT_NAK) && hcsplt.split_en && !channel_is_periodic(channel->hcchar)) { + xfer->retry_disabled = 1; + channel_disable(dwc2, channel); + } else { + channel_xfer_in_retry(dwc2, ch_id, hcint); + } } else if (hcint & HCINT_FARME_OVERRUN) { // retry start-split in next binterval channel_xfer_in_retry(dwc2, ch_id, hcint); @@ -1228,7 +1246,16 @@ static bool handle_channel_out_dma(dwc2_regs_t* dwc2, uint8_t ch_id, uint32_t hc // TU_LOG1("out hcint = %02lX\r\n", hcint); if (hcint & HCINT_HALTED) { - if (hcint & (HCINT_XFER_COMPLETE | HCINT_STALL)) { + if (xfer->retry_disabled) { + // Halt from our split-XactErr throttle disable (below): re-issue the start-split (pointers already + // rewound), giving the hub TT a recovery gap. Programming Guide 3.5 "Halting a Channel" (p73). + xfer->retry_disabled = 0; + if (xfer->closing) { + is_done = true; + } else { + channel_xfer_start(dwc2, ch_id); + } + } else if (hcint & (HCINT_XFER_COMPLETE | HCINT_STALL)) { is_done = true; xfer->err_count = 0; if (hcint & HCINT_XFER_COMPLETE) { @@ -1251,9 +1278,17 @@ static bool handle_channel_out_dma(dwc2_regs_t* dwc2, uint8_t ch_id, uint32_t hc xfer->result = XFER_RESULT_FAILED; is_done = true; } else { - // clean up transfer so far and start again + // Rewind, then retry the start-split. Non-periodic SPLIT throttles via channel_disable + re-arm on + // the halt (immediate re-fire exhausts the retry budget; the disable gives the hub TT a recovery + // gap, like slave). Periodic split is excluded: channel_disable() is a no-op for it, so the halt + // never fires and the channel would wedge. Non-split re-inits immediately (Programming Guide 5.1.2.3). channel_xfer_out_wrapup(dwc2, ch_id); - channel_xfer_start(dwc2, ch_id); + if (hcsplt.split_en && !channel_is_periodic(channel->hcchar)) { + xfer->retry_disabled = 1; + channel_disable(dwc2, channel); + } else { + channel_xfer_start(dwc2, ch_id); + } } } } else if (hcint & HCINT_NYET) { @@ -1271,6 +1306,12 @@ static bool handle_channel_out_dma(dwc2_regs_t* dwc2, uint8_t ch_id, uint32_t hc channel->hcsplt = hcsplt.value; channel->hcchar |= HCCHAR_CHENA; } + } else if ((hcint & HCINT_NAK) && hcsplt.split_en) { + // Split OUT NAK: rewind + retry the start-split, else the channel stalls (Programming Guide 5.1.4.2). + // Non-split OUT NAK is core-handled (5.1.2.2), so this is split-only. + xfer->err_count = 0; + channel_xfer_out_wrapup(dwc2, ch_id); + channel_xfer_start(dwc2, ch_id); } if (xfer->closing == 1) { -- cgit v1.3.1