TI WiFi Kernel Module Example

Warning

The TIWiFi module example is here for example purposes only, the driver is currently bundled with Linux on supported targets. If you want to try this example you must first remove the TIWiFi driver from Linux and rebuild your Linux Distribution.

The TI WiFi module provides an example of a complicated install and remove script for multiple modules as well as dependencies on multiple kernel modules.

The TI WiFi driver is comprised of 3 kernel modules:

• wlcore: needs install and remove scripts
• wlcore_sdio
• wp18xx: needs install and remove scripts

The load sequence for the modules is (the unload sequence is done in reverse):

1. wlcore 2. wlcore_sdio 3. wl18xx

All three modules must be called in your systems .sdef file:

{
    $LEGATO_ROOT/drivers/wl18xx/wl18xx.mdef
    $LEGATO_ROOT/drivers/wlcore/wlcore.mdef
    $LEGATO_ROOT/drivers/wlcore_sdio/wlcore_sdio.mdef
}

The wlcore kernel module contains multiple source files as well as 2 binary files. These must be defined in the wlcore.mdef as follows:

//-------------------------------------------------------------------------------------------------
// wlcore.mdef
//
// Copyright (C) Sierra Wireless Inc.
//-------------------------------------------------------------------------------------------------

sources:
{
    acx.c
    ps.c
    tx.c
    cmd.c
    debugfs.c
    event.c
    io.c
    main.c
    scan.c
    boot.c
    init.c
    rx.c
    sysfs.c
    vendor_cmd.c
}

bundles:
{
    file:
    {
        $CURDIR/bin/wl18xx-conf.bin /bin/wl18xx-conf.bin
        $CURDIR/bin/wl18xx-fw-4.bin /bin/wl18xx-fw-4.bin
    }
}

scripts:
{
    install: $CURDIR/scripts_wlcore/install.sh
    remove: $CURDIR/scripts_wlcore/remove.sh
}

To install the wlcore kernel module we need to use an install and remove script as we need to:

• point the kernel to where the binaries will be available on the target
• enable the GPIO pins
• resolve the module dependencies
• install modules already included in the Linux distribution (msm_sdcc, cfg80211, mac80211)
• install wlcore

Install Script:

#!/bin/sh
# Copyright (C) Sierra Wireless Inc.
#
# TI wireless wl18xx specific applications start or stop here
# TI WIFI IoT board is managed by SDIO/MMC bus. Some signals need to be set
# and managed before the SDIO/MMC module is inserted.
# TI WIFI IoT conflicts with others devices using the SDIO/MMC bus

export PATH=$PATH:/usr/bin:/bin:/usr/sbin:/sbin

KO_PATH=$1

echo -n /legato/systems/current/modules/files/wlcore/bin > /sys/module/firmware_class/parameters/path

# Add mdev rule for crda
grep crda /etc/mdev.conf > /dev/null
if [ $? -ne 0 ]; then
   (mount | grep -q " on /etc type ") || \
       (cp /etc/mdev.conf /tmp; mount -o bind /tmp/mdev.conf /etc/mdev.conf)
   echo "\$COUNTRY=.. root:root 0660 */sbin/crda" >> /etc/mdev.conf
fi
lsmod | grep wlcore >/dev/null
if [ $? -ne 0 ]; then
   # Check if MMC/SDIO module is inserted. Because WIFI use SDIO/MMC bus
   # we need to remove the SDIO/MMC module
   lsmod | grep msm_sdcc >/dev/null
  if [ $? -eq 0 ]; then
      grep -q mmcblk /proc/mounts
      if [ $? -ne 0 ]; then
         rmmod msm_sdcc
      else
         false
      fi
      if [ $? -ne 0 ]; then
         # Unable to remove. May be others devices use SDIO/MMC bus
         echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
         echo "Unable to remove the SDIO/MMC module... May be in use ?"
         echo "Please, free all SDIO/MMC devices before using TI WIFI."
         echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
         exit 127
      fi
   fi
   # Enable all GPIOs on all EXPANDERs
   gpioexp 1 1 enable >/dev/null || exit 127

   ### mangOH green has 3 expanders
   # Set IOTO_RESET, GPIO#4/EXPANDER#3 - IOT0 Reset signal is disabled
   gpioexp 3 4 output normal high >/dev/null 2>&1
   if [ $? -ne 0 ]; then
       echo "mangOH red board"

       # Set IOT0_GPIO2 = 1 (WP GPIO13)
       [ -d /sys/class/gpio/gpio13 ] || echo 13 >/sys/class/gpio/export
       echo out >/sys/class/gpio/gpio13/direction
       echo 1 >/sys/class/gpio/gpio13/value

       # Set IOT0_RESET = 1 (WP GPIO2)
       [ -d /sys/class/gpio/gpio2 ] || echo 2 >/sys/class/gpio/export
       echo out >/sys/class/gpio/gpio2/direction
       echo 1 >/sys/class/gpio/gpio2/value

       # Clear SDIO_SEL, GPIO#9/EXPANDER#1 - Select the SDIO
       gpioexp 1 9 output normal low >/dev/null || exit 127
   else
       echo "mangOH green board"
       # Set IOT0_GPIO2 = 1 (WP GPIO33)
       [ -d /sys/class/gpio/gpio33 ] || echo 33 >/sys/class/gpio/export
       echo out >/sys/class/gpio/gpio33/direction
       echo 1 >/sys/class/gpio/gpio33/value

       # Clear SDIO_SEL, GPIO#13/EXPANDER#1 - Select the SDIO
       gpioexp 1 13 output normal low >/dev/null || exit 127
   fi

   # Set IOT0_GPIO4 = 1 (WP GPIO8)
   [ -d /sys/class/gpio/gpio8 ] || echo 8 >/sys/class/gpio/export
   echo out >/sys/class/gpio/gpio8/direction
   echo 1 >/sys/class/gpio/gpio8/value

   modprobe msm_sdcc || exit 127
   modprobe cfg80211 || exit 127
   modprobe mac80211 || exit 127

   insmod $KO_PATH || exit 127

fi

The removal script must:

• remove the dependencies on the modules in the Linux distribution (msm_sdcc, cfg80211, mac80211)
• disable the GPIO pins
• remove the wlcore module

Remove Script:

#!/bin/sh
# Copyright (C) Sierra Wireless Inc.
#
# TI wireless wl18xx specific applications start or stop here
# TI WIFI IoT board is managed by SDIO/MMC bus. Some signals need to be set
# and managed before the SDIO/MMC module is inserted.
# TI WIFI IoT conflicts with others devices using the SDIO/MMC bus

export PATH=$PATH:/usr/bin:/bin:/usr/sbin:/sbin

KO_PATH=$1

lsmod | grep wlcore >/dev/null
if [ $? -eq 0 ]; then
   rmmod $KO_PATH || exit 127
   rmmod mac80211 || exit 127
   rmmod cfg80211 || exit 127
   if `lsmod | grep '^compat '`; then
       rmmod compat || exit 127
   fi

   rmmod msm-sdcc || exit 127

   # Reset IOT0_GPIO4 = 0 (WP GPIO8)
   echo 0 >/sys/class/gpio/gpio8/value
   # Clear IOTO_RESET, GPIO#4/EXPANDER#3 - IOT0 Reset signal is enabled
   gpioexp 3 4 output normal low >/dev/null 2>&1
   if [ $? -ne 0 ]; then
       echo "mangOH red board"
       # Set IOT0_RESET = 1 (WP GPIO2)
       echo 0 >/sys/class/gpio/gpio2/value

       # Clear SDIO_SEL, GPIO#9/EXPANDER#1 - Deselect the SDIO
       gpioexp 1 9 output normal high >/dev/null || exit 127

       # Reset IOT0_GPIO2 = 0 (WP GPIO13)
       echo 0 >/sys/class/gpio/gpio13/value
   else
       echo "mangOH green board"
       # Set SDIO_SEL, GPIO#13/EXPANDER#1 - Deselect the SDIO
       gpioexp 1 13 output normal high >/dev/null || exit 127

       # Reset IOT0_GPIO2 = 0 (WP GPIO33)
       echo 0 >/sys/class/gpio/gpio33/value
   fi

   # Insert MMC/SDIO module
   modprobe msm_sdcc || exit 127
fi

The wlcore_sdio module has only one source file sdio.c and has dependency on wlcore. The module dependency is indicated in the mdef with requires: kernelModules: section.

sources:
{
    sdio.c
}

requires:
{
    kernelModules:
    {
        $LEGATO_ROOT/drivers/wlcore/wlcore.mdef
    }
}

The wp18xx module is made up of multiple source files and also needs to use an install and removal script to correctly install the kernel module.

wl18xx.mdef:

sources:
{
    acx.c
    cmd.c
    debugfs.c
    event.c
    io.c
    main.c
    scan.c
    tx.c
}

requires:
{
    kernelModules:
    {
        $LEGATO_ROOT/drivers/wlcore_sdio/wlcore_sdio.mdef
    }
}

scripts:
{
    install: $CURDIR/scripts_wl18xx/install.sh
    remove:  $CURDIR/scripts_wl18xx/remove.sh
}

The install script for the wp18xx module needs to install the module and enable the wlan0 interface:

#!/bin/sh
# Copyright (C) Sierra Wireless Inc.
#
# TI wireless wl18xx specific applications start or stop here
# TI WIFI IoT board is managed by SDIO/MMC bus. Some signals need to be set
# and managed before the SDIO/MMC module is inserted.
# TI WIFI IoT conflicts with others devices using the SDIO/MMC bus

export PATH=$PATH:/usr/bin:/bin:/usr/sbin:/sbin

KO_PATH=$1

insmod $KO_PATH

sleep 62

ifconfig -a | grep wlan0 >/dev/null
if [ $? -ne 0 ] ; then
    echo "Failed to start TI wifi"; exit 126
fi
ifconfig wlan0 up >/dev/null
if [ $? -ne 0 ] ; then
    echo "Failed to start TI wifi"; exit 127
fi

And the removal script needs to disable the wlan0 interface and remove the module:

#!/bin/sh
# Copyright (C) Sierra Wireless Inc.
#
# TI wireless wl18xx specific applications start or stop here
# TI WIFI IoT board is managed by SDIO/MMC bus. Some signals need to be set
# and managed before the SDIO/MMC module is inserted.
# TI WIFI IoT conflicts with others devices using the SDIO/MMC bus

export PATH=$PATH:/usr/bin:/bin:/usr/sbin:/sbin

KO_PATH=$1

ifconfig | grep wlan0 >/dev/null
if [ $? -eq 0 ]; then
    ifconfig wlan0 down
fi
lsmod | grep wlcore >/dev/null
if [ $? -eq 0 ]; then
    rmmod $KO_PATH
fi

You should now be able to build your system including the kernel module and update your target with the new system including the TI WiFi modules.

Once the new system is installed on your target you should be able to find the TI WiFi files in the following location:

/legato/systems/current/modules
    ├── files
    │   ├── wl18xx
    │   │   └── scripts
    │   │       ├── install.sh
    │   │       └── remove.sh
    │   └── wlcore
    │       ├── bin
    │       │   ├── wl18xx-conf.bin
    │       │   └── wl18xx-fw-4.bin
    │       └── scripts
    │           ├── install.sh
    │           └── remove.sh
    ├── wl18xx.ko
    ├── wlcore.ko
    └── wlcore_sdio.ko