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authorLinus Torvalds <torvalds@linux-foundation.org>2024-09-26 09:45:36 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2024-09-26 09:45:36 -0700
commit4965ddb166992557a25848049f1a70e56050eb7a (patch)
tree530e827ac6016e87c000354d2a8de97001900c99 /Documentation/filesystems
parent13882369ceb9b0953f9f5ff8563bbccfd80d0ffd (diff)
parent68d4209158f43a558c5553ea95ab0c8975eab18c (diff)
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Merge tag 'usb-6.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb
Pull USB/Thunderbolt updates from Greg KH: "Here is the large set of USB and Thunderbolt changes for 6.12-rc1. Nothing "major" in here, except for a new 9p network gadget that has been worked on for a long time (all of the needed acks are here) Other than that, it's the usual set of: - Thunderbolt / USB4 driver updates and additions for new hardware - dwc3 driver updates and new features added - xhci driver updates - typec driver updates - USB gadget updates and api additions to make some gadgets more configurable by userspace - dwc2 driver updates - usb phy driver updates - usbip feature additions - other minor USB driver updates All of these have been in linux-next for a long time with no reported issues" * tag 'usb-6.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (145 commits) sub: cdns3: Use predefined PCI vendor ID constant sub: cdns2: Use predefined PCI vendor ID constant USB: misc: yurex: fix race between read and write USB: misc: cypress_cy7c63: check for short transfer USB: appledisplay: close race between probe and completion handler USB: class: CDC-ACM: fix race between get_serial and set_serial usb: r8a66597-hcd: make read-only const arrays static usb: typec: ucsi: Fix busy loop on ASUS VivoBooks usb: dwc3: rtk: Clean up error code in __get_dwc3_maximum_speed() usb: storage: ene_ub6250: Fix right shift warnings usb: roles: Improve the fix for a false positive recursive locking complaint locking/mutex: Introduce mutex_init_with_key() locking/mutex: Define mutex_init() once net/9p/usbg: fix CONFIG_USB_GADGET dependency usb: xhci: fix loss of data on Cadence xHC usb: xHCI: add XHCI_RESET_ON_RESUME quirk for Phytium xHCI host usb: dwc3: imx8mp: disable SS_CON and U3 wakeup for system sleep usb: dwc3: imx8mp: add 2 software managed quirk properties for host mode usb: host: xhci-plat: Parse xhci-missing_cas_quirk and apply quirk usb: misc: onboard_usb_dev: add Microchip usb5744 SMBus programming support ...
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r--Documentation/filesystems/9p.rst58
1 files changed, 57 insertions, 1 deletions
diff --git a/Documentation/filesystems/9p.rst b/Documentation/filesystems/9p.rst
index d270a0aa8d55..2bbf68b56b0d 100644
--- a/Documentation/filesystems/9p.rst
+++ b/Documentation/filesystems/9p.rst
@@ -48,11 +48,66 @@ For server running on QEMU host with virtio transport::
mount -t 9p -o trans=virtio <mount_tag> /mnt/9
-where mount_tag is the tag associated by the server to each of the exported
+where mount_tag is the tag generated by the server to each of the exported
mount points. Each 9P export is seen by the client as a virtio device with an
associated "mount_tag" property. Available mount tags can be
seen by reading /sys/bus/virtio/drivers/9pnet_virtio/virtio<n>/mount_tag files.
+USBG Usage
+==========
+
+To mount a 9p FS on a USB Host accessible via the gadget at runtime::
+
+ mount -t 9p -o trans=usbg,aname=/path/to/fs <device> /mnt/9
+
+To mount a 9p FS on a USB Host accessible via the gadget as root filesystem::
+
+ root=<device> rootfstype=9p rootflags=trans=usbg,cache=loose,uname=root,access=0,dfltuid=0,dfltgid=0,aname=/path/to/rootfs
+
+where <device> is the tag associated by the usb gadget transport.
+It is defined by the configfs instance name.
+
+USBG Example
+============
+
+The USB host exports a filesystem, while the gadget on the USB device
+side makes it mountable.
+
+Diod (9pfs server) and the forwarder are on the development host, where
+the root filesystem is actually stored. The gadget is initialized during
+boot (or later) on the embedded board. Then the forwarder will find it
+on the USB bus and start forwarding requests.
+
+In this case the 9p requests come from the device and are handled by the
+host. The reason is that USB device ports are normally not available on
+PCs, so a connection in the other direction would not work.
+
+When using the usbg transport, for now there is no native usb host
+service capable to handle the requests from the gadget driver. For
+this we have to use the extra python tool p9_fwd.py from tools/usb.
+
+Just start the 9pfs capable network server like diod/nfs-ganesha e.g.::
+
+ $ diod -f -n -d 0 -S -l 0.0.0.0:9999 -e $PWD
+
+Optionaly scan your bus if there are more then one usbg gadgets to find their path::
+
+ $ python $kernel_dir/tools/usb/p9_fwd.py list
+
+ Bus | Addr | Manufacturer | Product | ID | Path
+ --- | ---- | ---------------- | ---------------- | --------- | ----
+ 2 | 67 | unknown | unknown | 1d6b:0109 | 2-1.1.2
+ 2 | 68 | unknown | unknown | 1d6b:0109 | 2-1.1.3
+
+Then start the python transport::
+
+ $ python $kernel_dir/tools/usb/p9_fwd.py --path 2-1.1.2 connect -p 9999
+
+After that the gadget driver can be used as described above.
+
+One use-case is to use it as an alternative to NFS root booting during
+the development of embedded Linux devices.
+
Options
=======
@@ -68,6 +123,7 @@ Options
virtio connect to the next virtio channel available
(from QEMU with trans_virtio module)
rdma connect to a specified RDMA channel
+ usbg connect to a specified usb gadget channel
======== ============================================
uname=name user name to attempt mount as on the remote server. The