On Thu, Feb 06, 2025 at 02:48:24PM +0800, Jeremy Kerr wrote: > Add an implementation for DMTF DSP0283, which defines a MCTP-over-USB > transport. As per that spec, we're restricted to full speed mode, > requiring 512-byte transfers. > > Each MCTP-over-USB interface is a peer-to-peer link to a single MCTP > endpoint, so no physical addressing is required (of course, that MCTP > endpoint may then bridge to further MCTP endpoints). Consequently, > interfaces will report with no lladdr data: > > # mctp link > dev lo index 1 address 00:00:00:00:00:00 net 1 mtu 65536 up > dev mctpusb0 index 6 address none net 1 mtu 68 up > > This is a simple initial implementation, with single rx & tx urbs, and > no multi-packet tx transfers - although we do accept multi-packet rx > from the device. > > Includes suggested fixes from Santosh Puranik <spuranik@xxxxxxxxxx>. > > Signed-off-by: Jeremy Kerr <jk@xxxxxxxxxxxxxxxxxxxx> > Cc: Santosh Puranik <spuranik@xxxxxxxxxx> > --- > drivers/net/mctp/Kconfig | 10 ++ > drivers/net/mctp/Makefile | 1 + > drivers/net/mctp/mctp-usb.c | 367 ++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 378 insertions(+) > > diff --git a/drivers/net/mctp/Kconfig b/drivers/net/mctp/Kconfig > index 15860d6ac39fef62847d7186f1f0d81c1d3cd619..cf325ab0b1ef555e21983ace1b838e10c7f34570 100644 > --- a/drivers/net/mctp/Kconfig > +++ b/drivers/net/mctp/Kconfig > @@ -47,6 +47,16 @@ config MCTP_TRANSPORT_I3C > A MCTP protocol network device is created for each I3C bus > having a "mctp-controller" devicetree property. > > +config MCTP_TRANSPORT_USB > + tristate "MCTP USB transport" > + depends on USB > + help > + Provides a driver to access MCTP devices over USB transport, > + defined by DMTF specification DSP0283. > + > + MCTP-over-USB interfaces are peer-to-peer, so each interface > + represents a physical connection to one remote MCTP endpoint. > + > endmenu > > endif > diff --git a/drivers/net/mctp/Makefile b/drivers/net/mctp/Makefile > index e1cb99ced54ac136db0347a9ee0435a5ed938955..c36006849a1e7d04f2cafafb8931329fc0992b63 100644 > --- a/drivers/net/mctp/Makefile > +++ b/drivers/net/mctp/Makefile > @@ -1,3 +1,4 @@ > obj-$(CONFIG_MCTP_SERIAL) += mctp-serial.o > obj-$(CONFIG_MCTP_TRANSPORT_I2C) += mctp-i2c.o > obj-$(CONFIG_MCTP_TRANSPORT_I3C) += mctp-i3c.o > +obj-$(CONFIG_MCTP_TRANSPORT_USB) += mctp-usb.o > diff --git a/drivers/net/mctp/mctp-usb.c b/drivers/net/mctp/mctp-usb.c > new file mode 100644 > index 0000000000000000000000000000000000000000..f44e3d418d9544b45cc0369c3c3fa4d6ca11cc29 > --- /dev/null > +++ b/drivers/net/mctp/mctp-usb.c > @@ -0,0 +1,367 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +/* > + * mctp-usb.c - MCTP-over-USB (DMTF DSP0283) transport binding driver. > + * > + * DSP0283 is available at: > + * https://www.dmtf.org/sites/default/files/standards/documents/DSP0283_1.0.1.pdf > + * > + * Copyright (C) 2024 Code Construct Pty Ltd It's 2025 :) > +static void mctp_usb_out_complete(struct urb *urb) > +{ > + struct sk_buff *skb = urb->context; > + struct net_device *netdev = skb->dev; > + struct mctp_usb *mctp_usb = netdev_priv(netdev); > + int status; > + > + status = urb->status; > + > + switch (status) { > + case -ENOENT: > + case -ECONNRESET: > + case -ESHUTDOWN: > + case -EPROTO: > + mctp_usb_stat_tx_dropped(netdev); > + break; > + case 0: > + mctp_usb_stat_tx_done(netdev, skb->len); > + netif_wake_queue(netdev); > + consume_skb(skb); > + return; > + default: > + dev_err(&mctp_usb->usbdev->dev, "%s: urb status: %d\n", > + __func__, status); This could flood the logs, are you sure you need it at dev_err() level? And __func__ is redundant, it's present in dev_*() calls already. > +static int mctp_usb_rx_queue(struct mctp_usb *mctp_usb) > +{ > + struct sk_buff *skb; > + int rc; > + > + skb = netdev_alloc_skb(mctp_usb->netdev, MCTP_USB_XFER_SIZE); > + if (!skb) > + return -ENOMEM; > + > + usb_fill_bulk_urb(mctp_usb->rx_urb, mctp_usb->usbdev, > + usb_rcvbulkpipe(mctp_usb->usbdev, mctp_usb->ep_in), > + skb->data, MCTP_USB_XFER_SIZE, > + mctp_usb_in_complete, skb); > + > + rc = usb_submit_urb(mctp_usb->rx_urb, GFP_ATOMIC); > + if (rc) { > + dev_err(&mctp_usb->usbdev->dev, "%s: usb_submit_urb: %d\n", > + __func__, rc); Again, __func__ is redundant. Same everywhere else in this file. thanks, greg k-h
