/**
* @brief Prepares for a transmit operation.
*
* @param[in] usbp pointer to the @p USBDriver object
* @param[in] ep endpoint number
*
* @notapi
*/
void usb_lld_prepare_transmit(USBDriver *usbp, usbep_t ep) {
size_t n;
USBInEndpointState *isp = usbp->epc[ep]->in_state;
uint32_t epr = STM32_USB->EPR[ep];
/* Transfer initialization.*/
n = isp->txsize;
if (n > (size_t)usbp->epc[ep]->in_maxsize)
n = (size_t)usbp->epc[ep]->in_maxsize;
/* Double buffering is always enabled for isochronous endpoints, and
although we overlap the two buffers for simplicity, we still need
to write to the right counter. The DTOG_TX bit indicates the buffer
that is currently in use by the USB peripheral, that is, the buffer
from which the next packet will be sent, so we need to write the
counter of that buffer.*/
USB_GET_DESCRIPTOR(ep)->TXCOUNT0 = (stm32_usb_pma_t)n;
if (EPR_EP_TYPE_IS_ISO(epr) && (epr & EPR_DTOG_TX))
USB_GET_DESCRIPTOR(ep)->TXCOUNT1 = (stm32_usb_pma_t)n;
if (isp->txqueued)
usb_packet_write_from_queue(USB_GET_DESCRIPTOR(ep),
isp->mode.queue.txqueue, n);
else
usb_packet_write_from_buffer(USB_GET_DESCRIPTOR(ep),
isp->mode.linear.txbuf, n);
}
/**
* @brief Starts a transmit operation on an IN endpoint.
*
* @param[in] usbp pointer to the @p USBDriver object
* @param[in] ep endpoint number
*
* @notapi
*/
void usb_lld_start_in(USBDriver *usbp, usbep_t ep) {
size_t n;
USBInEndpointState *isp = usbp->epc[ep]->in_state;
/* Transfer initialization.*/
n = isp->txsize;
if (n > (size_t)usbp->epc[ep]->in_maxsize)
n = (size_t)usbp->epc[ep]->in_maxsize;
isp->txlast = n;
usb_packet_write_from_buffer(ep, isp->txbuf, n);
EPR_SET_STAT_TX(ep, EPR_STAT_TX_VALID);
}
/**
* @brief Prepares for a transmit operation.
*
* @param[in] usbp pointer to the @p USBDriver object
* @param[in] ep endpoint number
*
* @notapi
*/
void usb_lld_prepare_transmit(USBDriver *usbp, usbep_t ep) {
size_t n;
USBInEndpointState *isp = usbp->epc[ep]->in_state;
/* Transfer initialization.*/
n = isp->txsize;
if (n > (size_t)usbp->epc[ep]->in_maxsize)
n = (size_t)usbp->epc[ep]->in_maxsize;
if (isp->txqueued)
usb_packet_write_from_queue(USB_GET_DESCRIPTOR(ep),
isp->mode.queue.txqueue, n);
else
usb_packet_write_from_buffer(USB_GET_DESCRIPTOR(ep),
isp->mode.linear.txbuf, n);
}
/**
* @brief Common ISR code, serves the EP-related interrupts.
*
* @param[in] usbp pointer to the @p USBDriver object
* @param[in] ep endpoint number
*
* @notapi
*/
static void usb_serve_endpoints(USBDriver *usbp, uint32_t ep) {
size_t n;
uint32_t epr = STM32_USB->EPR[ep];
const USBEndpointConfig *epcp = usbp->epc[ep];
if (epr & EPR_CTR_TX) {
/* IN endpoint, transmission.*/
USBInEndpointState *isp = epcp->in_state;
EPR_CLEAR_CTR_TX(ep);
isp->txcnt += isp->txlast;
n = isp->txsize - isp->txcnt;
if (n > 0) {
/* Transfer not completed, there are more packets to send.*/
if (n > epcp->in_maxsize)
n = epcp->in_maxsize;
/* Writes the packet from the defined buffer.*/
isp->txbuf += isp->txlast;
isp->txlast = n;
usb_packet_write_from_buffer(ep, isp->txbuf, n);
/* Starting IN operation.*/
EPR_SET_STAT_TX(ep, EPR_STAT_TX_VALID);
}
else {
/* Transfer completed, invokes the callback.*/
_usb_isr_invoke_in_cb(usbp, ep);
}
}
if (epr & EPR_CTR_RX) {
/* OUT endpoint, receive.*/
EPR_CLEAR_CTR_RX(ep);
if (epr & EPR_SETUP) {
/* Setup packets handling, setup packets are handled using a
specific callback.*/
_usb_isr_invoke_setup_cb(usbp, ep);
}
else {
USBOutEndpointState *osp = epcp->out_state;
/* Reads the packet into the defined buffer.*/
n = usb_packet_read_to_buffer(ep, osp->rxbuf);
osp->rxbuf += n;
/* Transaction data updated.*/
osp->rxcnt += n;
osp->rxsize -= n;
osp->rxpkts -= 1;
/* The transaction is completed if the specified number of packets
has been received or the current packet is a short packet.*/
if ((n < epcp->out_maxsize) || (osp->rxpkts == 0)) {
/* Transfer complete, invokes the callback.*/
_usb_isr_invoke_out_cb(usbp, ep);
}
else {
/* Transfer not complete, there are more packets to receive.*/
EPR_SET_STAT_RX(ep, EPR_STAT_RX_VALID);
}
}
}
}
