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drivers: udc_dwc2: Disable endpoint while hibernated

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When the endpoint is disabled while the core is hibernated, there are
timeouts waiting for interrupts. It is not clear how the stack should
behave when class and/or application wants to disable the endpoint while
device is suspended. The problem was originally observed when the
endpoints were disabled as a result of usbd_disable() call.

Avoid the timeouts by modifying the backup values instead of the real
registers (which are not accessible when hibernated).

Split the 32-bit txf_set variable into two 16-bit variables (txf_set and
pending_tx_flush) because maximum number of TxFIFO instances is 16.
The txf_set variable is used as-is, while the pending_tx_flush is used
to keep track of TxFIFOs that have to be flushed on hibernation exit.

Signed-off-by: Tomasz Moń <tomasz.mon@nordicsemi.no>
This commit is contained in:
Tomasz Moń 2025-03-13 14:28:31 +01:00 • committed by Benjamin Cabé
commit 2be960ad2b
1 changed files with 45 additions and 1 deletions
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46
drivers/usb/udc/udc_dwc2.c
View file

@ -110,11 +110,12 @@ struct udc_dwc2_data {
struct k_event xfer_finished;
struct dwc2_reg_backup backup;
uint32_t ghwcfg1;
uint32_t txf_set;
uint32_t max_xfersize;
uint32_t max_pktcnt;
uint32_t tx_len[16];
uint32_t rx_siz[16];
uint16_t txf_set;
uint16_t pending_tx_flush;
uint16_t dfifodepth;
uint16_t rxfifo_depth;
uint16_t max_txfifo_depth[16];
@ -1484,6 +1485,7 @@ static int dwc2_unset_dedicated_fifo(const struct device *dev,
static void udc_dwc2_ep_disable(const struct device *dev,
struct udc_ep_config *const cfg, bool stall)
{
struct udc_dwc2_data *const priv = udc_get_private(dev);
struct usb_dwc2_reg *const base = dwc2_get_base(dev);
uint8_t ep_idx = USB_EP_GET_IDX(cfg->addr);
mem_addr_t dxepctl_reg;
@ -1493,6 +1495,40 @@ static void udc_dwc2_ep_disable(const struct device *dev,
dxepctl_reg = dwc2_get_dxepctl_reg(dev, cfg->addr);
dxepctl = sys_read32(dxepctl_reg);
if (priv->hibernated) {
/* Currently USB stack calls this function while hibernated,
* for example if usbd_disable() is called. We cannot access the
* real registers when hibernated, so just modify backup values
* that will be restored on hibernation exit.
*/
if (USB_EP_DIR_IS_OUT(cfg->addr)) {
dxepctl = priv->backup.doepctl[ep_idx];
dxepctl &= ~USB_DWC2_DEPCTL_EPENA;
if (stall) {
dxepctl |= USB_DWC2_DEPCTL_STALL;
} else {
dxepctl |= USB_DWC2_DEPCTL_SNAK;
}
priv->backup.doepctl[ep_idx] = dxepctl;
} else {
dxepctl = priv->backup.diepctl[ep_idx];
dxepctl &= ~USB_DWC2_DEPCTL_EPENA;
dxepctl |= USB_DWC2_DEPCTL_SNAK;
if (stall) {
dxepctl |= USB_DWC2_DEPCTL_STALL;
}
priv->backup.diepctl[ep_idx] = dxepctl;
priv->pending_tx_flush |= BIT(usb_dwc2_get_depctl_txfnum(dxepctl));
}
return;
}
if (!is_iso && (dxepctl & USB_DWC2_DEPCTL_NAKSTS)) {
/* Endpoint already sends forced NAKs. STALL if necessary. */
if (stall) {
@ -2162,6 +2198,7 @@ static int udc_dwc2_disable(const struct device *dev)
if (priv->hibernated) {
dwc2_exit_hibernation(dev, false, true);
priv->hibernated = 0;
priv->pending_tx_flush = 0;
}
sys_clear_bits((mem_addr_t)&base->gahbcfg, USB_DWC2_GAHBCFG_GLBINTRMASK);
@ -2926,6 +2963,13 @@ static void dwc2_handle_hibernation_exit(const struct device *dev,
k_event_post(&priv->drv_evt, BIT(DWC2_DRV_EVT_EP_FINISHED));
}
}
while (priv->pending_tx_flush) {
unsigned int fifo = find_lsb_set(priv->pending_tx_flush) - 1;
priv->pending_tx_flush &= ~BIT(fifo);
dwc2_flush_tx_fifo(dev, fifo);
}
}
static uint8_t pull_next_ep_from_bitmap(uint32_t *bitmap)