Author: hselasky Date: Thu May 28 08:38:25 2020 New Revision: 361581 URL: https://svnweb.freebsd.org/changeset/base/361581
Log: Implement helper function, usbd_get_max_frame_length(), which allows kernel device drivers to correctly predict the default USB transfer frame length. MFC after: 3 days Sponsored by: Mellanox Technologies Modified: head/sys/dev/usb/usb_transfer.c head/sys/dev/usb/usbdi.h Modified: head/sys/dev/usb/usb_transfer.c ============================================================================== --- head/sys/dev/usb/usb_transfer.c Thu May 28 08:20:16 2020 (r361580) +++ head/sys/dev/usb/usb_transfer.c Thu May 28 08:38:25 2020 (r361581) @@ -374,6 +374,81 @@ usbd_transfer_setup_sub_malloc(struct usb_setup_params #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 * * This function must be called from the "xfer_setup" callback of the Modified: head/sys/dev/usb/usbdi.h ============================================================================== --- head/sys/dev/usb/usbdi.h Thu May 28 08:20:16 2020 (r361580) +++ head/sys/dev/usb/usbdi.h Thu May 28 08:38:25 2020 (r361581) @@ -605,6 +605,9 @@ uint8_t usbd_get_interface_altindex(struct usb_interfa 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, _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"