| Age | Commit message (Collapse) | Author |
|---|
|
Add support for packet spanning as defined in DSP0283 v1.1.
With the existing v1.0 implementation of multi-packet transfers, all we
need here is to adjust the buffer sizes to suit v1.1.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Link: https://patch.msgid.link/20260724-dev-mctp-usb-1-1-v5-9-e66bbba0dbdc@codeconstruct.com.au
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
Using the existing prepare/complete API, we can persist the rx skb
across receives to implement v1.1 packet spanning.
Alter the packet-extraction loop to allow truncated packets, returning
early with the skb persisted for the next IN urb completion. When we see
we have a complete packet, netif_rx() that. If the packet boundary
aligns with the urb completion, we can netif_rx() the whole thing.
Those intermediate packets are cloned from the original
(large-transfer-data) skb. Unlike existing behaviour, if the clone
fails, we drop just that clone, instead of the existing transfer skb.
This allows us to process the rest of the skb data, and any continuation
of the span into the next transfer.
One subtle change: the mctp_usblib_rx() helper now handles skbs with the
full transport header, so we shift the skb_pull() for the header data to
the helper, before doing the rx_bytes stats update.
We still need to handle non-spanning mode, so error out on
truncated-packet cases there.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Link: https://patch.msgid.link/20260724-dev-mctp-usb-1-1-v5-8-e66bbba0dbdc@codeconstruct.com.au
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
In the v1.1 update to DSP0283, we have a larger header field, of 13 bits
rather than 8.
In order to accommodate this, in preparation for proper v1.1 support,
expand our struct mctp_usb_hdr's len field to a u16, and endian-convert
when necessary. Because we don't yet support spanning mode, we will
never receive or transmit with the top 5 bits set, so we always mask
out anyway.
This allows for a future change where we allow spanning mode with
>512-byte transfers.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Link: https://patch.msgid.link/20260724-dev-mctp-usb-1-1-v5-7-e66bbba0dbdc@codeconstruct.com.au
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
The MCTP over USB spec allows us to pack multiple packets in one
transfer. Given the packet max length is 255, and the transfer max
length is 512, we can typically include two full-size packets per
urb submission.
To do this, we allow a struct mctp_usb_tx to persist a tx_ctx,
representing the ongoing context for a transmit. If possible, a TX skb
will be queued to the context and the send deferred until the context is
full, or the device queue reports no more packets.
This typically requires a linear buffer for the 512-byte TX, which we
allocate along with the TX context.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Link: https://patch.msgid.link/20260724-dev-mctp-usb-1-1-v5-6-e66bbba0dbdc@codeconstruct.com.au
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
With the RX processing in mctp-usblib, add TX processing alongside.
To accommodate packed transfers in DSP0283, where a transfer may contain
multiple MCTP packets, we move to a split process for the transmit API:
* push: create a new transmit context, and add a skb to it.
* send: callback to the driver implementation to send the (possibly
multi-packet) USB transfer
* complete: update skb accounting and release the tx context
The actual multi-packet transfer implementation will be added in the
next change; no tx context persists beyond the single send at present.
However, we use an anchor in the host driver implementation to track the
submitted TX urb when necessary.
While we're here, fix an inconsistency between tx and rx stats: both
should not include the transport header.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Link: https://patch.msgid.link/20260724-dev-mctp-usb-1-1-v5-5-e66bbba0dbdc@codeconstruct.com.au
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
The processing of USB receive transfers is common to both sides of a
MCTP over USB transport. In order to support a future gadget driver,
move the current host-side driver into a new common file, mctp-usblib.
This currently handles the submit-complete-packetise process of the
receive path of the USB transport. We'll add transmit handling in an
upcoming change.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Link: https://patch.msgid.link/20260724-dev-mctp-usb-1-1-v5-3-e66bbba0dbdc@codeconstruct.com.au
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
The max packet size is smaller than the max transfer size, as we only
have a u8 length field in the transport header.
Add a define for the maximum representable length, and use that for our
check. Use this for the MTU maximum calculation too.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Link: https://patch.msgid.link/20260724-dev-mctp-usb-1-1-v5-2-e66bbba0dbdc@codeconstruct.com.au
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
DSP0283 v1.1.0 will introduce larger maximum packet sizes. In
preparation, indicate that the current maxima are specific to v1.0.x.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Link: https://patch.msgid.link/20260724-dev-mctp-usb-1-1-v5-1-e66bbba0dbdc@codeconstruct.com.au
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
Upcoming changes will add a USB host (and later gadget) driver for the
MCTP-over-USB protocol. Add a header that provides common definitions
for protocol support: the packet header format and a few framing
definitions. Add a define for the MCTP class code, as per
https://usb.org/defined-class-codes.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/20250221-dev-mctp-usb-v3-1-3353030fe9cc@codeconstruct.com.au
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
