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STM32 UDC: fix transmission on halted endpoints #93796

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STM32 UDC: fix transmission on halted endpoints #93796

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39 changes: 37 additions & 2 deletions drivers/usb/udc/udc_stm32.c
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The commit message does not look nice. You can have up to 75 characters per line in the commit message.

Manage endpoint halt state explicitly in set/clear halt functions.
Prevent transmissions on halted endpoints in enqueue function.
Trigger retransmission post-halt clearance if applicable.

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Done

Original file line number Diff line number Diff line change
Expand Up @@ -829,6 +829,14 @@ static int udc_stm32_ep_set_halt(const struct device *dev,
return -EIO;
}

/*
* Mark non-control endpoint as halted
* to indicate stall condition
*/
if (USB_EP_GET_IDX(cfg->addr) != 0) {
cfg->stat.halted = true;
}

return 0;
}

Expand All @@ -847,6 +855,22 @@ static int udc_stm32_ep_clear_halt(const struct device *dev,
return -EIO;
}

/* Clear halted state to resume normal operation */
cfg->stat.halted = false;

if (USB_EP_GET_IDX(cfg->addr) != 0U) {
struct net_buf *buf = udc_buf_peek(cfg);

/* Start IN (device-to-host) transfer if not busy */
if (buf != NULL && USB_EP_DIR_IS_IN(cfg->addr) && !udc_ep_is_busy(cfg)) {
udc_stm32_tx(dev, cfg, buf);
}
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What about the OUT direction? Do you need to restart anything explicitly here? I did not have time to look at the OUT path in my suggestion, so I just added a comment.

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Good point regarding the OUT direction. For OUT endpoints, I will add logic to re-arm the endpoint (e.g., by calling udc_stm32_rx()) to ensure it is ready to receive new data.
I’ll update the code accordingly.

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Done

/* Prepare OUT (host-to-device) transfer if busy */
else if (buf != NULL && USB_EP_DIR_IS_OUT(cfg->addr) && udc_ep_is_busy(cfg)) {
udc_stm32_rx(dev, cfg, buf);
}
}

return 0;
}

Expand Down Expand Up @@ -879,8 +903,19 @@ static int udc_stm32_ep_enqueue(const struct device *dev,

lock_key = irq_lock();

if (USB_EP_DIR_IS_IN(epcfg->addr)) {
ret = udc_stm32_tx(dev, epcfg, buf);
if (USB_EP_DIR_IS_IN(epcfg->addr) != 0U) {
if (!epcfg->stat.halted) {
/* Endpoint is not halted, safe to transmit data */
ret = udc_stm32_tx(dev, epcfg, buf);
} else {
/*
* Endpoint is halted (stalled) by the host.
* Skip transmission to avoid protocol violations
* and potential data corruption.
*/
LOG_DBG("ep 0x%02x halted", epcfg->addr);
ret = 0;
}
} else {
ret = udc_stm32_rx(dev, epcfg, buf);
}
Expand Down