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Implement helper function, usbd_get_max_frame_length(), which allows kernel

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device drivers to correctly predict the default USB transfer frame length.

MFC after:	3 days
Sponsored by:	Mellanox Technologies
This commit is contained in:
Hans Petter Selasky 2020-05-28 08:38:25 +00:00
parent 06592d60f0
commit 506a911bad
2 changed files with 78 additions and 0 deletions
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75
sys/dev/usb/usb_transfer.c
View File

@ -373,6 +373,81 @@ usbd_transfer_setup_sub_malloc(struct usb_setup_params *parm,
}
#endif
/*------------------------------------------------------------------------*
* usbd_get_max_frame_length
*
* This function returns the maximum single frame length as computed by
* usbd_transfer_setup(). It is useful when computing buffer sizes for
* devices having multiple alternate settings. The SuperSpeed endpoint
* companion pointer is allowed to be NULL.
*------------------------------------------------------------------------*/
uint32_t
usbd_get_max_frame_length(const struct usb_endpoint_descriptor *edesc,
const struct usb_endpoint_ss_comp_descriptor *ecomp,
enum usb_dev_speed speed)
{
uint32_t max_packet_size;
uint32_t max_packet_count;
uint8_t type;
max_packet_size = UGETW(edesc->wMaxPacketSize);
max_packet_count = 1;
type = (edesc->bmAttributes & UE_XFERTYPE);
switch (speed) {
case USB_SPEED_HIGH:
switch (type) {
case UE_ISOCHRONOUS:
case UE_INTERRUPT:
max_packet_count +=
(max_packet_size >> 11) & 3;
/* check for invalid max packet count */
if (max_packet_count > 3)
max_packet_count = 3;
break;
default:
break;
}
max_packet_size &= 0x7FF;
break;
case USB_SPEED_SUPER:
max_packet_count += (max_packet_size >> 11) & 3;
if (ecomp != NULL)
max_packet_count += ecomp->bMaxBurst;
if ((max_packet_count == 0) ||
(max_packet_count > 16))
max_packet_count = 16;
switch (type) {
case UE_CONTROL:
max_packet_count = 1;
break;
case UE_ISOCHRONOUS:
if (ecomp != NULL) {
uint8_t mult;
mult = UE_GET_SS_ISO_MULT(
ecomp->bmAttributes) + 1;
if (mult > 3)
mult = 3;
max_packet_count *= mult;
}
break;
default:
break;
}
max_packet_size &= 0x7FF;
break;
default:
break;
}
return (max_packet_size * max_packet_count);
}
/*------------------------------------------------------------------------*
* usbd_transfer_setup_sub - transfer setup subroutine
*

3
sys/dev/usb/usbdi.h
View File

@ -605,6 +605,9 @@ uint8_t usbd_get_interface_altindex(struct usb_interface *iface);
usb_error_t usbd_set_alt_interface_index(struct usb_device *udev,
uint8_t iface_index, uint8_t alt_index);
uint32_t usbd_get_isoc_fps(struct usb_device *udev);
uint32_t usbd_get_max_frame_length(const struct usb_endpoint_descriptor *,
const struct usb_endpoint_ss_comp_descriptor *,
enum usb_dev_speed);
usb_error_t usbd_transfer_setup(struct usb_device *udev,
const uint8_t *ifaces, struct usb_xfer **pxfer,
const struct usb_config *setup_start, uint16_t n_setup,