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openwrt/package/utils/usbgadget/files/usbgadget.init
Chuanhong Guo b196a9f6ce package: new package for usb gadget setup
Setting up usb gadgets using g_* kernel modules are considered a
legacy approach, but the usb_gadget configfs is a bit annoying
to use directly.
The usb_gadget configfs works by creating magic directories
and writing to magic files under /sys/kernel/config/usbgadget.
This new package is an init script to setup usb_gadget configfs
using uci. In the config file, gadget/configuration/function
sections create corresponding directories. UCI options are magic
files available in the configfs and strings/0x409 directories,
grabbed with a 'find' command. UDC option in gadget writes
the UDC file under the 'gadget' directory to attach the
generated gadget config.

It's also possible to apply pre-made config templates under
/usr/share/usbgadget. The templates use the same UCI config
format, with the 'gadget' entry named 'g1'. Currently, there
are templates for CDC-ACM and CDC-NCM gadgets written based
on existing g_*.ko module code.

Certain SBCs come with only a USB device port (e.g. Raspberry Pi
Zero). With this script, it's now possible to perform initial
setup on them by adding a default NCM gadget.

Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
2023-12-28 13:10:32 +08:00

145 lines
3.1 KiB
Bash

#!/bin/sh /etc/rc.common
START=19
GADGET_FS=/sys/kernel/config/usb_gadget
GADGET_PRESETS_DIR=/usr/share/usbgadget
GADGET_PREFIX=owrt_
log() {
logger -t usbgadget "$@"
}
apply_configs() {
local fs_path="$1"
local cfg="$2"
for param in $(find "$fs_path" -maxdepth 1 -type f -exec basename '{}' ';'); do
[ "$param" = "UDC" ] && continue
config_get val "$cfg" "$param"
[ -n "$val" ] && echo "$val" > "${fs_path}/${param}"
done
}
setup_gadget() {
local cfg="$1"
local gadget_path="${GADGET_FS}/${GADGET_PREFIX}${cfg}"
local param udc
config_get udc "$cfg" UDC
[ -z "$udc" ] && return
mkdir "$gadget_path" || return
apply_configs "$gadget_path" "$cfg"
local strings_path="${gadget_path}/strings/0x409"
mkdir "$strings_path"
apply_configs "$strings_path" "$cfg"
}
setup_configuration() {
local cfg="$1"
local gadget
config_get gadget "$cfg" gadget
local cfgs_path="${GADGET_FS}/${GADGET_PREFIX}${gadget}/configs"
[ -d "${cfgs_path}" ] || return
local cfg_path="${cfgs_path}/${cfg}.1"
mkdir "$cfg_path" || {
log "failed to create configuration ${cfg}"
return
}
apply_configs "$cfg_path" "$cfg"
local strings_path="${cfg_path}/strings/0x409"
mkdir "$strings_path"
apply_configs "$strings_path" "$cfg"
}
setup_function() {
local cfg="$1"
local usbcfg gadget usbfun
config_get usbcfg "$cfg" configuration
[ -z "$usbcfg" ] && return
config_get usbfun "$cfg" function
[ -z "$usbfun" ] && return
config_get gadget "$usbcfg" gadget
local gadget_path="${GADGET_FS}/${GADGET_PREFIX}${gadget}"
local cfg_path="${gadget_path}/configs/${usbcfg}.1"
[ -d "${cfg_path}" ] || return
local fun_path="${gadget_path}/functions/${usbfun}.${cfg}"
mkdir "$fun_path" || {
log "failed to create function ${usbfun}.${cfg}"
return
}
apply_configs "$fun_path" "$cfg"
ln -s "$fun_path" "$cfg_path"
}
attach_gadget() {
local cfg="$1"
local gadget_path="${GADGET_FS}/${GADGET_PREFIX}${cfg}"
local param udc
config_get udc "$cfg" UDC
[ -z "$udc" ] && return
echo "$udc" > "$gadget_path/UDC"
}
load_gadget() {
config_foreach setup_gadget gadget
config_foreach setup_configuration configuration
config_foreach setup_function function
config_foreach attach_gadget gadget
}
# use subshell for isolated env
apply_preset() (
local preset="$1"
local gadget="$2"
UCI_CONFIG_DIR=$GADGET_PRESETS_DIR config_load "$1"
config_set g1 UDC "$2"
load_gadget
)
load_preset() {
local cfg="$1"
config_get name "$cfg" name
config_get udc "$cfg" UDC
[ -z "$udc" ] && return
apply_preset $name $udc
}
start() {
grep -q /sys/kernel/config /proc/mounts || \
mount -t configfs configfs /sys/kernel/config
[ -d /sys/kernel/config/usb_gadget ] || {
log "usb_gadget support not found."
return 1
}
config_load usbgadget
config_foreach load_preset preset
load_gadget
}
stop() {
for gadget_path in ${GADGET_FS}/${GADGET_PREFIX}* ; do
[ -d "$gadget_path" ] || continue
echo "" > ${gadget_path}/UDC
find ${gadget_path}/configs -maxdepth 2 -type l -exec rm '{}' ';'
rmdir ${gadget_path}/configs/*/strings/*
rmdir ${gadget_path}/configs/*
rmdir ${gadget_path}/functions/*
rmdir ${gadget_path}/strings/*
rmdir $gadget_path
done
}