Fishwaldo commented on code in PR #19745:
URL: https://github.com/apache/nuttx/pull/19745#discussion_r3788719225
##########
drivers/usbhost/usbhost_xhci.c:
##########
@@ -3835,6 +3835,68 @@ static int xhci_ep0configure(FAR struct usbhost_driver_s
*drvr,
return ret;
}
+/****************************************************************************
+ * Name: xhci_interval
+ *
+ * Description:
+ * Work out the Interval an endpoint context wants.
+ *
+ * The field is an exponent: the controller services the endpoint every
+ * 2^Interval microframes. An endpoint descriptor does not say it that
+ * way, and what it does say depends on how fast the device is, so the
+ * number cannot simply be copied across.
+ *
+ * A low or full speed interrupt endpoint counts in frames, so its period
+ * is bInterval milliseconds, or bInterval * 8 microframes, and the
+ * exponent is the position of the highest bit of that. Everything else
+ * that is periodic already states an exponent, one greater than the one
+ * wanted here. Control and bulk endpoints are not periodic and the field
+ * means nothing to them.
+ *
+ ****************************************************************************/
+
+static uint8_t xhci_interval(uint8_t speed, uint8_t xfrtype,
+ uint8_t interval)
+{
+ unsigned int exp;
+
+ if (xfrtype != USB_EP_ATTR_XFER_INT && xfrtype != USB_EP_ATTR_XFER_ISOC)
+ {
+ return 0;
+ }
+
+ if ((speed == USB_SPEED_LOW || speed == USB_SPEED_FULL) &&
+ xfrtype == USB_EP_ATTR_XFER_INT)
+ {
+ /* Frames. Round down to a power of two, and keep it inside what the
+ * specification allows for this kind of endpoint: 2^3 microframes is
+ * one frame, 2^10 is 128 of them.
+ */
+
+ if (interval == 0)
+ {
+ interval = 1;
+ }
+
+ for (exp = 0; (1u << (exp + 1)) <= (unsigned int)interval * 8; exp++);
Review Comment:
Fixed.
##########
drivers/usbhost/usbhost_xhci.c:
##########
@@ -3835,6 +3835,68 @@ static int xhci_ep0configure(FAR struct usbhost_driver_s
*drvr,
return ret;
}
+/****************************************************************************
+ * Name: xhci_interval
+ *
+ * Description:
+ * Work out the Interval an endpoint context wants.
+ *
+ * The field is an exponent: the controller services the endpoint every
+ * 2^Interval microframes. An endpoint descriptor does not say it that
+ * way, and what it does say depends on how fast the device is, so the
+ * number cannot simply be copied across.
+ *
+ * A low or full speed interrupt endpoint counts in frames, so its period
+ * is bInterval milliseconds, or bInterval * 8 microframes, and the
+ * exponent is the position of the highest bit of that. Everything else
+ * that is periodic already states an exponent, one greater than the one
+ * wanted here. Control and bulk endpoints are not periodic and the field
+ * means nothing to them.
+ *
+ ****************************************************************************/
+
+static uint8_t xhci_interval(uint8_t speed, uint8_t xfrtype,
+ uint8_t interval)
+{
+ unsigned int exp;
+
+ if (xfrtype != USB_EP_ATTR_XFER_INT && xfrtype != USB_EP_ATTR_XFER_ISOC)
+ {
+ return 0;
+ }
+
+ if ((speed == USB_SPEED_LOW || speed == USB_SPEED_FULL) &&
+ xfrtype == USB_EP_ATTR_XFER_INT)
+ {
+ /* Frames. Round down to a power of two, and keep it inside what the
+ * specification allows for this kind of endpoint: 2^3 microframes is
+ * one frame, 2^10 is 128 of them.
+ */
+
+ if (interval == 0)
+ {
+ interval = 1;
+ }
+
+ for (exp = 0; (1u << (exp + 1)) <= (unsigned int)interval * 8; exp++);
+
+ if (exp < 3)
+ {
+ exp = 3;
+ }
+ else if (exp > 10)
+ {
+ exp = 10;
+ }
+
+ return (uint8_t)exp;
Review Comment:
Fixed.
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
