Linux Software Features

1 Console
- 1.1 How to enable framebuffer console
- 1.2 How to change debug console port
- 1.3 How to disable debug console
  - 1.3.1 Ltib
2 Device Tree
3 File System
- 3.1 NTFS
4 Fonts
- 4.1 Chinese Font
5 GStreamer
- 5.1 Play Video
- 5.2 SMPTE color bar
- 5.3 video rotation
- 5.4 webcam
- 5.5 network streaming
  - 5.5.1 RTSP(unicast)
  - 5.5.2 RTP(multicast)
6 Java
7 Linux Kernel
- 7.1 Get kernel configs from running OS
- 7.2 Debug kernel panic and oops
- 7.3 Dynamic Voltage and Frequency Scaling (DVFS)
  - 7.3.1 CPUFreq & OPP
  - 7.3.2 CPU Governor
8 NFS
- 8.1 boot up to Linux
- 8.2 boot up to U-Boot
9 OpenCV
10 Python
11 Qt
- 11.1 Setting-up QtCreator to cross compile for iMX6 series]
- 11.2 Writing the Qt application with displaying Chinese
12 SSH
13 TFTP
- 13.1 boot up to Linux
14 WiFi AP mode
- 14.1 before buildinging sdcard image
- 14.2 after booting-up
- 14.3 after reboot
15 Yocto
- 15.1 How to delete temporary workspace after build process
- 15.2 How to get multi-sources from GIT server
- 15.3 Skip QA check
- 15.4 Create BB file to install pre-built SO binaries
- 15.5 Install Node-RED packages
- 15.6 How to add additional gst-plugins
- 15.7 How to use Yocto Project Application Development Toolkit (ADT)
- 15.8 How to add & use Chromium browser
16 CC2650 Sensortag
- 16.1 Set up bluetooth module
- 16.2 Test Sensor
- 16.3 Set up NodeRed
- 16.4 Sending Data to Azure IoT Hub by NodeRed
- 16.5 Sending Data to Azure IoT Hub by tools of Azure IoT SDK
17 Bluetooth
18 Bluetooth_Yocto
19 GPS
20 Touch
21 RT-Patch
- 21.1 Description
- 21.2 Implementation Steps
- 21.3 Real-Time Kernel Performance
22 USB-Boot
- 22.1 Description
- 22.2 Implementation Steps
23 Customized GPIO Function
- 23.1 Description

Console

How to enable framebuffer console

The following operations are performed with RSB-4410(4410LBV2080)

linux kernel config

Device Drivers --->

Graphics support --->

<*> Framebuffer Console support

u-boot

setenv bootargs_base 'setenv bootargs console=ttymxc0,115200 console=tty0 enable_wait_mode=off video_mode=extension

files need to be updated

/etc/inittab

tty0::respawn:-/bin/bash

Notice:

If the kernel config is set to "<M> Framebuffer Console support", console will show up after module ,fbcon, is loaded.

How to change debug console port

Ltib

The following operations demonstrate how to change UBC-DS31's(based on DS31LBV1150) debug console from UART1(ttymxc0) to UART2(ttymxc1).

u-boot

include/configs/mx6q_ubc-d31_recovery.h

#define CONFIG_UART_BASE_ADDR   UART2_BASE_ADDR

include/configs/mx6q_ubc-d31_1G_recovery.h

modify the settings of bootargs_base contained in the pre-defined macro #define CONFIG_EXTRA_ENV_SETTINGS

console=ttymxc1,115200

board/freescale/mx6q_ubc-d31/mx6q_ubc-d31.c

insert the following two lines into static void setup_uart(void)

mxc_iomux_v3_setup_pad(MX6Q_PAD_EIM_D27__UART2_TXD);
mxc_iomux_v3_setup_pad(MX6Q_PAD_EIM_D27__UART2_RXD);

linux kernel

arch/arm/mach-mx6/board-mx6q_advantech.c

modify the following two lines in static void __init mx6_sabresd_timer_init(void)

uart_clk = clk_get_sys("imx-uart.1", NULL);
early_console_setup(UART2_BASE_ADDR, uart_clk);

Ltib

The following operations demonstrate how to change ROM-3420 's(based on imx6LBV2310_2014-04-30) debug console from UART1(ttymxc0) to UART2(ttymxc1)「Hardward Pin Define MX6Q_PAD_SD3_DAT5__UART2 _TXD & MX6Q_PAD_SD3_DAT4__UART2_RXD 」

U-boot modified port:

Path : ROM-3420\imx6LBV2310_2014-04-30\source\u-boot-2009.08\board\freescale\mx6q_rom-3420\mx6q_rom-3420.c
static void setup_uart(void)

{

#if defined CONFIG_MX6Q

           /* UART1 TXD */

           //mxc_iomux_v3_setup_pad(MX6Q_PAD_CSI0_DAT10__UART1_TXD);

 

           /* UART1 RXD */

           //mxc_iomux_v3_setup_pad(MX6Q_PAD_CSI0_DAT11__UART1_RXD);

          

           /* UART2 TXD */

           mxc_iomux_v3_setup_pad(MX6Q_PAD_SD3_DAT5__UART2_TXD);

 

           /* UART2 RXD */

           mxc_iomux_v3_setup_pad(MX6Q_PAD_SD3_DAT4__UART2_RXD);

          

#elif defined CONFIG_MX6DL

           /* UART1 TXD */

           mxc_iomux_v3_setup_pad(MX6DL_PAD_CSI0_DAT10__UART1_TXD);

 

           /* UART1 RXD */

           mxc_iomux_v3_setup_pad(MX6DL_PAD_CSI0_DAT11__UART1_RXD);

#endif

}

.

Path: \ROM-3420\imx6LBV2310_2014-04-30\source\u-boot-2009.08\include\configs\mx6q_rom-3420_1G.h

 

/*

 * Hardware drivers

 */

#define CONFIG_MXC_UART

//#define CONFIG_UART_BASE_ADDR   UART1_BASE_ADDR

#define CONFIG_UART_BASE_ADDR   UART2_BASE_ADDR

Kernel modified port :

 

Path: ROM-3420\imx6LBV2310_2014-04-30\source\linux-3.0.35\arch\arm\mach-mx6\board-mx6q_advantech.c

 

static void __init mx6_sabresd_timer_init(void)

{

           struct clk *uart_clk;

#ifdef CONFIG_LOCAL_TIMERS

           twd_base = ioremap(LOCAL_TWD_ADDR, SZ_256);

           BUG_ON(!twd_base);

#endif

           mx6_clocks_init(32768, 24000000, 0, 0);

 

           //uart_clk = clk_get_sys("imx-uart.0", NULL);

           //early_console_setup(UART1_BASE_ADDR, uart_clk);

                     uart_clk = clk_get_sys("imx-uart.1", NULL);

           early_console_setup(UART2_BASE_ADDR, uart_clk);

}

Rebuild BSP
U-boot Rebuild:

~/ROM-3420/imx6LBV2310_2014-04-30/scripts$ . setenv.sh

(To configure the development environment automatically)

~/ROM-3420/imx6LBV2310_2014-04-30/scripts$ ./cfg_uboot.sh mx6q_rom-3420_1G_config

 (To set the u-boot configuration automatically)

~/ROM-3420/imx6LBV2310_2014-04-30/scripts$ ./mk_uboot.sh

(Start to build the u-boot)

 

Then you can see u-boot_crc.bin and u-boot_crc.bin.crc are being built and

located in ../image.

===================================================================================

 

 

Kernel Rebuild:

~/ROM-3420/imx6LBV2310_2014-04-30/scripts$  . setenv.sh

(To configure the development environment automatically)

~/ROM-3420/imx6LBV2310_2014-04-30/scripts$./cfg_kernel.sh imx6_rom3420_defconfig

(To set the uImage configuration automatically)

~/ROM-3420/imx6LBV2310_2014-04-30/scripts$ ./mk_kernel.sh

(Start to build the uImage)

 

 

Then you can see uImage is being built and located in ../image.

===================================================================================

U-boot parameter modified port when you turn on the device .
Command:

setenv bootargs_base setenv bootargs console=ttymxc1,115200 enable_wait_mode=off video_mode=extension pcie_testmode=off

Yocto

Modify u-boot

Here we take ROM-5420 as an example

We want to change debug port from UART1 to UART2

include/configs/mx6rom5420.h

-#define CONFIG_MXC_UART_BASE   UART1_BASE
-#define CONFIG_CONSOLE_DEV             "ttymxc0"
+#define CONFIG_MXC_UART_BASE   UART2_BASE
+#define CONFIG_CONSOLE_DEV             "ttymxc1"

board/freescale/mx6advantech/mx6advantech.c

static iomux_v3_cfg_t const uart1_pads[] = {
        MX6_PAD_CSI0_DAT10__UART1_TX_DATA | MUX_PAD_CTRL(UART_PAD_CTRL),
        MX6_PAD_CSI0_DAT11__UART1_RX_DATA | MUX_PAD_CTRL(UART_PAD_CTRL),
};
 
+static iomux_v3_cfg_t const uart2_pads[] = {
+       MX6_PAD_EIM_D26__UART2_TX_DATA | MUX_PAD_CTRL(UART_PAD_CTRL),
+       MX6_PAD_EIM_D27__UART2_RX_DATA | MUX_PAD_CTRL(UART_PAD_CTRL),
+};
+

static void setup_iomux_uart(void)
{
        imx_iomux_v3_setup_multiple_pads(uart1_pads, ARRAY_SIZE(uart1_pads));
+       imx_iomux_v3_setup_multiple_pads(uart2_pads, ARRAY_SIZE(uart2_pads));
}

After re-compile u-boot and replace , you may be need to clear u-boot env to make kernel debug message output from uart2

env default -a
env save
reset

Note(in rootfs)

Due to /etc/init.d/rc_mxc.S only get ttymxc0~ttymxc3 from u-boot parameter If you want to change to ttymxc4 and so on, you need to modify this file first /etc/init.d/rc_mxc.S

if grep -sq ttymxc0 /proc/cmdline; then
        /sbin/getty -L ttymxc0 115200 vt100
elif grep -sq ttymxc1 /proc/cmdline; then
        /sbin/getty -L ttymxc1 115200 vt100
elif grep -sq ttymxc2 /proc/cmdline; then
        /sbin/getty -L ttymxc2 115200 vt100
elif grep -sq ttymxc3 /proc/cmdline; then
        /sbin/getty -L ttymxc3 115200 vt100
elif grep -sq ttymxc4 /proc/cmdline; then
       /sbin/getty -L ttymxc4 115200 vt100
else
        sleep 100000
fi

How to disable debug console

Ltib

The following operations demonstrate how to disable UBC-DS31's(based on DS31LBV1150) debug console.

u-boot

board/freescale/mx6q_ubc-d31/mx6q_ubc-d31.c

comment out all the code within static void setup_uart(void)

common/console.c

modify the following line in int console_init_f(void)

gd->have_console = 0;

u-boot environment variable

setenv silent=y

change console setting, console=none, within bootargs_base

linux kernel config

Device Drivers ---> Character devices ---> Serial drivers --->

[*] IMX serial port support

[ ] Support 4 IMX serial ports

[ ] Console on IMX serial port

linux kernel (recommended)

arch/arm/boot/compressed/misc.c

comment out the following lines in void decompress_kernel (...

//putstr("Uncompressing Linux...");

/*
if (ret)
        error("decompressor returned an error");
else
        putstr(" done, booting the kernel.\n");
*/

target root file system

comment out the following line in /etc/inittab

#::respawn:/etc/rc.d/rc_mxc.S

Device Tree

Customize device tree

File System

NTFS

The following operations demonstrate how to add NTFS support for Yocto Linux (ROM-5420 with imx6LBV6120_2016-06-14).

linux kernel config (please refer to this for details)

File systems --->

DOS/FAT/NT Filesystems --->

<*> NTFS file system support

BSP

add one line to meta-advantech/recipes-fsl/images/fsl-image-adv.inc

IMAGE_INSTALL += " fuse ntfs-3g ntfs-3g-ntfsprogs "

rebuild the sdcard image (please refer to this for details)

$ bitbake fsl-image-qt5

Fonts

Chinese Font

The following operations demonstrate how to install Chinese font on Yocto Linux (RSB-4410 with 4410A1LIV6000).

get the free Chinese font "WenQuanYi Micro Hei" from [SourceForge] and extract the tarball
put the wqy-microhei.ttc to /usr/share/fonts/ttf, then execute the following commands

 $ ln -s /usr/share/fonts/ttf/wqy-microhei.ttc /usr/lib/fonts/
 $ fc-cache -fv

use the the following command to check if the font is recognized.

 $ fc-list

set the Chinese locale

install the suitable locale if needed

 $ rpm -ivh locale-base-zh-tw-2.21-r0.cortexa9hf_vfp_neon.rpm glibc-binary-localedata-zh-tw-2.21-r0.cortexa9hf_vfp_neon.rpm
 $ rpm -ivh locale-base-zh-cn-2.21-r0.cortexa9hf_vfp_neon.rpm glibc-binary-localedata-zh-cn-2.21-r0.cortexa9hf_vfp_neon.rpm

put the suitable LC_ALL setting to the /etc/profile

 export LC_ALL=zh_TW.UTF-8

or

 export LC_ALL=zh_CN.UTF-8

reboot the target device

verification

plug in the USB stick that the following directories and files already existed

chinese_test/
 繁體目錄/
  繁體檔案
chinese_test/
 简体目录/
  简体档案

check if the keyword "utf8" is existed

$ mount

if not, execute the following command then check again

 $ umount /dev/sda1
 $ mount -o iocharset=utf8 /dev/sda1 /run/media/sda1
 ## NOTICE: the following format also works
 ## mount -o utf8 /dev/sda1 /run/media/sda1
 $ mount

or

if it is, execute the following command to list the directories and files

$ ls -al /run/media/sda1/chinese_test/*

GStreamer

Play Video

Audio Information

When the system is turned on, you can see the following audio information:

...
ALSA device list:
 #0: imx-audio-sgtl5000
 #1: imx-hdmi-soc
...

Frame Buffer Information

After the system is turned on, you can type command to see frame buffer information. For example:

1. Type command "ls /dev/video", you will see all frame buffer devices ID:

$ video16  video17  video18  video19  video20

2. Type command "cat /sys/class/graphics/fb0/fsl_disp_dev_property", you will see frame buffer name:

$ hdmi

3. The device ID of "hdmi" frame buffer layer is "video16".

4. Type command "cat /sys/class/graphics/fb1/fsl_disp_dev_property", you will see frame buffer name:

$ overlay

5. The device ID of "hdmi" overlay layer is "video17".

6. Type command "cat /sys/class/graphics/fb2/fsl_disp_dev_property", you will see frame buffer name:

$ lcd

7. The device ID of "lcd" frame buffer layer is "video18".

8. Type command "cat /sys/class/graphics/fb3/fsl_disp_dev_property", you will see frame buffer name:

$ overlay

9. The device ID of "lcd" overlay layer is "video19".

10. Type command "cat /sys/class/graphics/fb4/fsl_disp_dev_property", you will see frame buffer name:

$ ldb

11. The device ID of "ldb" frame buffer layer is "video20".

Play Video Command

The format of display video command:

$ GST_COMMAND uri=file://VIDEO_PATH video-sink="VIDEO_COMMAND device=DISPLAY_ID" audio-sink="alsasink device=plughw:AUDIO_ID"

Play Video Command On Yocto 1.5

1. For example:

GST_COMMAND = "gst-launch playbin2"
VIDEO_PATH = "/tools/Advantech.avi"
VIDEO_COMMAND = "mfw_v4lsink"
DISPLAY_ID = "/dev/video17"(hdmi overlay layer)
AUDIO_ID = "0"(audio-sgtl5000) or "1"(audio-hdmi)
AUDIO = ""(Audio) or "volume=0"(No audio)

2. Play video with audio from sgtl5000 audio command:

$ gst-launch playbin2 uri=file:///tools/Advantech.avi video-sink="mfw_v4lsink device=/dev/video17" audio-sink="alsasink device=plughw:0"

3. Play video with audio from HDMI audio command:

$ gst-launch playbin2 uri=file:///tools/Advantech.avi video-sink="mfw_v4lsink device=/dev/video17" audio-sink="alsasink device=plughw:1"

4. Play video with no audio command:

$ gst-launch playbin2 uri=file:///tools/Advantech.avi video-sink="mfw_v4lsink device=/dev/video17" \
  audio-sink="alsasink device=plughw:0" volume=0
or
$ gst-launch playbin2 uri=file:///tools/Advantech.avi video-sink="mfw_v4lsink device=/dev/video17" \
   audio-sink="alsasink device=plughw:1" volume=0

Play Video Command On Yocto 1.7

1. For example:

GST_COMMAND = "gst-launch playbin2" or "gst-launch-0.10 playbin2" or "gst-launch-1.0 playbin"
VIDEO_PATH = "/tools/Advantech.avi"
VIDEO_COMMAND = "imxv4l2sink"
DISPLAY_ID = "/dev/video17"(hdmi overlay layer)
AUDIO_ID = "0"(audio-sgtl5000) or "1"(audio-hdmi)
AUDIO = ""(Audio) or "volume=0"(No audio)

2. Play video with audio from SGTL5000 audio command:

$ gst-launch playbin2 uri=file:///tools/Advantech.avi video-sink="imxv4l2sink device=/dev/video17" audio-sink="alsasink  device=plughw:0"
or
$ gst-launch-0.10 playbin2 uri=file:///tools/Advantech.avi video-sink="imxv4l2sink device=/dev/video17" audio-sink="alsasink  device=plughw:0"
or
$ gst-launch-1.0 playbin uri=file:///tools/Advantech.avi video-sink="imxv4l2sink device=/dev/video17" audio-sink="alsasink  device=plughw:0"

3. Play video with audio from HDMI audio command:

$ gst-launch playbin2 uri=file:///tools/Advantech.avi video-sink="imxv4l2sink device=/dev/video17" audio-sink="alsasink device=plughw:1"
or
$ gst-launch-0.10 playbin2 uri=file:///tools/Advantech.avi video-sink="imxv4l2sink device=/dev/video17" audio-sink="alsasink device=plughw:1"
or
$ gst-launch-1.0 playbin uri=file:///tools/Advantech.avi video-sink="imxv4l2sink device=/dev/video17" audio-sink="alsasink device=plughw:1"

4. Play video with no audio command:

$ gst-launch playbin2 uri=file:///tools/Advantech.avi video-sink="imxv4l2sink device=/dev/video17" \
  audio-sink="alsasink device=plughw:0" volume=0
or
$ gst-launch-1.0 playbin uri=file://tools/Advantech.avi video-sink="imxv4l2sink device=/dev/video17" \
  audio-sink="alsasink device=plughw:0" volume=0

Play Video Command On Yocto 1.8

1. For example:

GST_COMMAND = "gst-launch-1.0 playbin"
VIDEO_PATH = "/tools/Advantech.avi"
VIDEO_COMMAND = "imxv4l2sink"
DISPLAY_ID = "/dev/video17"(hdmi overlay layer)
AUDIO_ID = "0"(audio-sgtl5000) or "1"(audio-hdmi)
AUDIO = ""(Audio) or "volume=0"(No audio)

2. Play video with audio from SGTL5000 audio command:

$ gst-launch-1.0 playbin uri=file:///tools/Advantech.avi video-sink="imxv4l2sink device=/dev/video17" audio-sink="alsasink device=plughw:0"

3. Play video with audio from HDMI audio command:

$ gst-launch-1.0 playbin uri=file:///tools/Advantech.avi video-sink="imxv4l2sink device=/dev/video17" audio-sink="alsasink device=plughw:1"

4. Play video with no audio command:

$ gst-launch-1.0 playbin uri=file://tools/Advantech.avi video-sink="imxv4l2sink device=/dev/video17" \
  audio-sink="alsasink device=plughw:0" volume=0
or
$ gst-launch-1.0 playbin uri=file://tools/Advantech.avi video-sink="imxv4l2sink device=/dev/video17" \
  audio-sink="alsasink device=plughw:1" volume=0

SMPTE color bar

gst-launch videotestsrc ! autovideosink

video rotation

gst-launch filesrc location=/tools/Advantech.avi typefind=true ! aiurdemux name=demux demux. ! \
queue max-size-buffers=0 max-size-time=0 ! vpudec ! mfw_v4lsink rotate=180 demux. ! \
queue max-size-buffers=0 max-size-time=0 ! beepdec ! autoaudiosink

(valid rotate value: 0, 90, 180 or 270)

(While the angle of rotation is 90° or 270°, the maximum video resolution can not be larget than 1024*1024.)

or

gst-launch playbin2 uri=file:///tools/Advantech.avi video-sink="mfw_isink rotation=0"

(valid rotation value: 0~7)

webcam

realtime video

gst-launch v4l2src ! video/x-raw-yuv,width=640,height=480,framerate=20/1 ! autovideosink

take one snapshot

gst-launch v4l2src num-buffers=1 ! jpegenc ! filesink location=sample.jpeg

show one snapshot

VSALPHA=1 gst-launch filesrc location=sample.jpeg ! jpegdec ! imagefreeze ! mfw_isink

network streaming

RTSP(unicast)

sender (ip: 192.168.203.41)

vlc -I rc H.264.mp4 --screen-fps=10 :screen-caching=100 --sout='#rtp{sdp=rtsp://8554/}' -vvv

receiver

gst-launch rtspsrc location=rtsp://192.168.203.41:8554 \
latency=200 name=r  r. ! application/x-rtp,media=video ! \
queue max-size-buffers=0 max-size-time=0 ! rtph264depay ! \
vpudec ! mfw_v4lsink sync=false async=false r. ! \
'application/x-rtp, media=(string)audio' ! queue max-size-buffers=0 max-size-time=0 ! \
rtpmp4gdepay ! beepdec ! alsasink sync=false async=false -vvv

RTP(multicast)

sender

vlc -I rc H.264.mp4 --screen-fps=10 :screen-caching=100 --sout='#rtp{mux=ts,dst=239.1.1.1,port=5004}' -vvv

receiver

route add -net 224.0.0.0 netmask 240.0.0.0 dev eth0 
gst-launch  udpsrc uri=udp://239.1.1.1:5004 \
caps="application/x-rtp,media=(string)video,clock-rate=(int)90000,encoding-name=(string)H264"\
! .recv_rtp_sink_0 gstrtpbin ! queue max-size-buffers=0 max-size-time=0 ! \
rtpmp2tdepay ! mpegtsdemux name=tsdem tsdem. ! queue max-size-buffers=0 max-size-time=0 ! \
vpudec ! mfw_isink sync=false tsdem. tsdem. ! queue max-size-buffers=0 max-size-time=0 ! \
beepdec  ! alsasink sync=false -vvv

Java

How to install Java

Linux Kernel

Get kernel configs from running OS

You can get the .config file in running Linux OS by the following command.

# zcat /proc/config.gz > current.config

Furthermore, this feature is enabled by CONFIG_IKCONFIG_PROC.

Debug kernel panic and oops

To enable kernel symbols & debug information, you have to turn on these options and re-build kernel image. Just remember to keep the vmlinux & System.map files for debugging. They should be located at kernel root folder.

CONFIG_DEBUG_KERNEL=y
CONFIG_KALLSYMS=y
CONFIG_DEBUG_INFO=y
# CONFIG_DEBUG_INFO_REDUCED is not set

Here is an example of Oops case.

Unable to handle kernel NULL pointer dereference at virtual address 00000000
pgd = d8e3c000
[00000000] *pgd=68d76831, *pte=00000000, *ppte=00000000
Internal error: Oops: 17 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 1 PID: 1030 Comm: pulseaudio Not tainted 3.14.52-svn2009 #3
task: d8f90000 ti: d8b6c000 task.ti: d8b6c000
PC is at dac_get_volsw+0x60/0x74
LR is at dac_get_volsw+0x5c/0x74
pc : [<80558e68>]    lr : [<80558e64>]    psr: 60070013
sp : d8b6dea8  ip : 00000000  fp : d8617400
r10: 7ef214f8  r9 : d8b6c000  r8 : d866e280
r7 : d861757c  r6 : d8617600  r5 : d8948800  r4 : 00000000
r3 : 00000000  r2 : 00000000  r1 : 00000001  r0 : 0000e564
Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
Control: 10c53c7d  Table: 68e3c04a  DAC: 00000015
Process pulseaudio (pid: 1030, stack limit = 0xd8b6c238)
Stack: (0xd8b6dea8 to 0xd8b6e000)
dea0:                   80558e08 00000001 d8948800 80535bf4 f01ad000 d861757c
dec0: 00000000 00000009 00000009 00000009 0035f648 00000000 00000000 00000000
dee0: 00000000 00000000 00000000 80967f28 00000007 8001a3c4 6df18338 d8b6dfb0
df00: 00000003 0035f960 7ef21aa4 d80cb410 7ef214f8 d87d53c0 c2c85512 0000000d
df20: d8b6c000 00000000 7ef217f4 800e7f4c d87d53c8 800ebfc0 6ddcf000 800d2e14
df40: 80962860 0000000d 0035ccf8 8069fa10 0000000d 800f19e4 d87d53c0 d87d53c0
df60: 7ef21d94 8069fc88 00000802 d87d53c0 7ef214f8 d87d53c0 c2c85512 0000000d
df80: d8b6c000 00000000 7ef217f4 800e8140 00361b58 00361cbc 00000000 00000036
dfa0: 8000e5e4 8000e460 00361b58 00361cbc 0000000d c2c85512 7ef214f8 0035cdd8
dfc0: 00361b58 00361cbc 00000000 00000036 00361ab0 00361b68 00000007 7ef217f4
dfe0: 6dfa73ac 7ef214ec 6df0efa4 76a5ecbc 20070010 0000000d 00000000 00000000
[<80558e68>] (dac_get_volsw) from [<80535bf4>] (snd_ctl_ioctl+0x5dc/0xb18)
[<80535bf4>] (snd_ctl_ioctl) from [<800e7f4c>] (do_vfs_ioctl+0x3dc/0x59c)
[<800e7f4c>] (do_vfs_ioctl) from [<800e8140>] (SyS_ioctl+0x34/0x5c)
[<800e8140>] (SyS_ioctl) from [<8000e460>] (ret_fast_syscall+0x0/0x38)
Code: e26330fc e585304c eb0501a0 e30e0564 (e5941000)
---[ end trace 7c4f0a24c41cc488 ]---

1. Check the PC (Program Counter) to find out where crash occurs.

PC is at dac_get_volsw+0x60/0x74

2. Grep dac_get_volsw() in System.map and get the symbol name address

$ cd <kernel root folder>
$ grep dac_get_volsw System.map
80558e08 t dac_get_volsw

Note: You can find the program counter is equaled to the sum of function entry address & offset.

pc : [<80558e68>] = 80558e08 + 0x60

3. Run addr2line to read the exact line number in source code.

$ arm-linux-gnueabi-addr2line -f -e vmlinux 80558e68
dac_get_volsw
/home/root/Projects/Linux/fsl-yocto-3.14.52_1.1.0/linux-imx/sound/soc/codecs/sgtl5000.c:335

4-1. In alternative way, you can run objdump to get the disassembly and source code mapping.

$ arm-linux-gnueabi-objdump -DS vmlinux > kernel.objdump

Note: This step may take very long time to generate the dump file. So, maybe you can stop it, once you can find the function symbols in the file.

4-2. Find dac_get_volsw() in kernel.objdump, and check the pc address [<80558e68>]. Then, you can find the problem occurs at the same line of source code.

80558e08 <dac_get_volsw>:
 *                      ------------------------------
 * userspace value      0xc0                         0
 */
static int dac_get_volsw(struct snd_kcontrol *kcontrol,
                         struct snd_ctl_elem_value *ucontrol)
{
80558e08:       e92d4038        push    {r3, r4, r5, lr}
80558e0c:       e1a05001        mov     r5, r1
 ...
        //TEST
        printk("crash test!\n");
80558e60:       eb0501a0        bl      806994e8 <printk>
        printk("%d\n", *p);
80558e64:       e30e0564        movw    r0, #58724      ; 0xe564
80558e68:       e5941000        ldr     r1, [r4]
80558e6c:       e3480080        movt    r0, #32896      ; 0x8080
80558e70:       eb05019c        bl      806994e8 <printk>

Dynamic Voltage and Frequency Scaling (DVFS)

CPUFreq & OPP

CPUFreq is a feature in Linux kernel to allow users to change the clock speed of the CPUs. It can save battery power, because the lower the clock speed, the less power the CPU consumes. Different SoC vendors should implement their own mapping table for CPU frequency and voltage pairs. These pairs that the device will support per domain are called Operating Performance Points or OPPs.

Below are OPP tables for each platform:

NXP i.MX6 Quad/Dual

CPU Frequency (kHz)	Voltage (uV)
1200000 (*)	1275000
996000 (*)	1250000
852000 (*)	1250000
792000	1175000
396000	975000

(*) The highest frequency depends on the CPU types (08/10/12 which means 800MHz, 1GHz, and 1.2GHz respectively). Now most our projects are 1GHz.

NXP i.MX6 Dual Lite/Solo

CPU Frequency (kHz)	Voltage (uV)
996000	1250000
792000	1175000
396000	1150000

TI AM335x

CPU Frequency (kHz)	Voltage (uV)
1000000	1325000
800000	1260000
720000	1200000
600000	1100000
300000 (*)	1100000

(*) We disable this frequency after V1.140.

TI AM57xx

CPU Frequency (kHz)	Voltage (uV)
1500000	1210000
1176000	1160000
1000000	1060000

Qualcomm APQ8016

CPU Frequency (kHz)	Voltage (uV)
1209600	1350000
1152000	1350000
1094400	1350000
998400	1350000
800000	1150000
533330	1150000
400000	1050000
200000	1050000

CPU Governor

In order to offer dynamic frequency scaling, Linux kernel provides a feature named "cpufreq governors". There are 6 modes in recent version.

Governor	Description
performance	Set the CPU to the highest frequency
powersave	Set the CPU to the lowest frequency
userspace	Allows the user to set the CPU to a specific frequency by making a sysfs file "scaling_setspeed" available in the CPU-device directory.
ondemand	Sets the CPU depending on the current usage.
conservative	Much like the "ondemand" governor, sets the CPU depending on the current usage. It differs in behavior in that it gracefully increases and decreases the CPU speed rather than jumping to max speed the moment there is any load on the CPU.
interactive	Sets the CPU speed depending on usage, similar to "ondemand" and "conservative" governors, but with a different set of configurable behaviors. It's is designed for latency-sensitive, interactive workloads.

For more CPU frequency settings, you can check the path below.

$ ls /sys/devices/system/cpu/cpu0/cpufreq/
affected_cpus     cpuinfo_transition_latency     scaling_cur_freq  scaling_min_freq
cpuinfo_cur_freq  related_cpus                   scaling_driver    scaling_setspeed
cpuinfo_max_freq  scaling_available_frequencies  scaling_governor  stats
cpuinfo_min_freq  scaling_available_governors    scaling_max_freq

For example, you can list the available governor, and know current governor.

$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors
interactive conservative userspace powersave ondemand performance

$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
ondemand

You can change to new governor.

$ echo "performance" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
performance

In ondemand, interactive or conservative mode, you can configure further.

$ ls /sys/devices/system/cpu/cpufreq/ondemand
ignore_nice_load  powersave_bias        sampling_rate      up_threshold
io_is_busy        sampling_down_factor  sampling_rate_min

$ ls /sys/devices/system/cpu/cpufreq/interactive
above_hispeed_delay  boostpulse_duration  io_is_busy       timer_rate
boost                go_hispeed_load      min_sample_time  timer_slack
boostpulse           hispeed_freq         target_loads

$ ls /sys/devices/system/cpu/cpufreq/conservative
down_threshold  ignore_nice_load      sampling_rate      up_threshold
freq_step       sampling_down_factor  sampling_rate_min

NFS

boot up to Linux

The following operations demonstrate how to boot-up RSB-4410(4410LBV3480/4410LBV2080) with loading kernel image and mounting the root filesystem via NFS.

prerequisites for NFS server (e.g. ip: 172.22.15.145)
- NFS root

add the following line to /etc/exports

<tt><small>/NFS *(rw,sync,wdelay,hide,nocrossmnt,insecure,no_root_squash,no_all_squash,subtree_check,secure_locks,acl,anonuid=65534,anongid=65534)</small></tt>

execute the following command to export all directories
$ sudo exportfs -a
- make one copy of the individual BSP's rootfs located in the directory, /NFS
for 4410LBV3480
copy the following three files included in 4410LBV3480 to /NFS/rsb-4410_rootfs

uImage imx6q-rsb4410.dtb u-boot_crc.bin
for 4410LBV2080
copy the uImage (which CONFIG_ROOT_NFS is set) to /NFS/4410lbv2

set the following lines to /NFS/4410lbv2/etc/rc.d/rc.conf

export DEPLOYMENT_STYLE="NFS"
export IPADDR0="dhcp"

u-boot

Hit any key to stop autoboot then perform the following commands:

for 4410LBV3480

> setenv serverip 172.22.15.145; setenv autoload n; dhcp
> setenv nfsroot /NFS/rsb-4410_rootfs
> run netargs
> nfs ${loadaddr} ${nfsroot}/${uimage}
> nfs ${fdt_addr} ${nfsroot}/${fdt_file}
> bootm ${loadaddr} - ${fdt_addr}

for 4410LBV2080

> setenv serverip 172.22.15.145; setenv autoload n; dhcp
> setenv nfsroot /NFS/4410lbv2
> setenv bootargs_base ${bootargs_base} 'fec_mac=${ethaddr}'
> run bootargs_base bootargs_nfs
> nfs ${loadaddr} ${nfsroot}/uImage
> bootm

screenshot

for 4410LBV3480

for 4410LBV2080

boot up to U-Boot

The following operations demonstrate how to boot-up RSB-4410(4410LBV3480) with loading u-boot via NFS.

Keep the DEL key pressed in terminal emulator, then reset RSB-4410.
While "SPL >" shows up, release the DEL key, and type "CTRL+C" in terminal emulator to clear all invisible keystrokes.
SPL

> setenv serverip 172.22.15.145
> dhcp
> nfs ${loadaddr} /NFS/rsb-4410_rootfs/u-boot_crc.bin
> go ${loadaddr}

Screenshot

OpenCV

Open source computer vision

Python

Install Python

Qt

Setting-up QtCreator to cross compile for iMX6 series]

Writing the Qt application with displaying Chinese

The section will demonstrate how to install Chinese font, and let Qt application to display Chinese; all operations are performed with RSB-4410 (4410A1LIV6000) and Ubuntu 12.04.

install Chinese font

On target side (RSB-4410)

Please refer to this for details.

On host side (Ubuntu 12.04)

perform the following command

# sudo apt-get install ttf-wqy-microhei

start QtCreator (on host side)

create one project named hello_qt that contains one label which text is "哈囉 Qt" and font is "WenQuanYi Micro Hei, 72"

(please refer to Setting-up QtCreator to cross compile for iMX6 series if needed)

build , deploy and run

SSH

SSH connection

TFTP

boot up to Linux

The following operations demonstrate how to boot-up RSB-4410(4410LBV3480/4410LBV2080) with loading kernel image via TFTP and mounting the root filesystem via NFS.

prerequisites for NFS server (This section is identical with the one of NFS.)
prerequisites for TFTP server (e.g. ip: 172.22.15.145)

/etc/xinetd.d/tftp

service tftp
{
    socket_type     = dgram
    protocol        = udp
    wait            = yes
    user            = root
    server          = /usr/sbin/in.tftpd
    server_args     = -s /tftpboot
    disable         = no
}

/etc/services

tftp            69/tcp
tftp            69/udp

restart the xinetd service

u-boot

Hit any key to stop autoboot then perform the following commands:

for 4410LBV3480

> setenv serverip 172.22.15.145
> setenv nfsroot /NFS/rsb-4410_rootfs
> run netboot

for 4410LBV2080

> setenv serverip 172.22.15.145; setenv autoload n; dhcp
> setenv nfsroot /NFS/4410lbv2
> setenv bootargs_base ${bootargs_base} 'fec_mac=${ethaddr}'
> run bootcmd_net

WiFi AP mode

The following operations demonstrate how to turn UBC-220(U220LBV8220) with EMM-160M2 plugged to a wireless AP.

before buildinging sdcard image

./meta-advantech/meta-fsl-imx6/recipes-fsl/images/fsl-image-adv.inc

add the following line

IMAGE_INSTALL += " hostapd "

If you also want to setup bridge, add the following line

IMAGE_INSTALL += " bridge-utils "

after booting-up

/etc/sysctl.conf

net.ipv4.ip_forward=1

/etc/network/interfaces

# /etc/network/interfaces -- configuration file for ifup(8), ifdown(8)

# The loopback interface
auto lo
iface lo inet loopback

# Wired or wireless interfaces
auto eth0
iface eth0 inet dhcp

auto eth0:0
iface eth0:0 inet static
       address 192.168.203.220
       netmask 255.255.255.0

# Wireless interfaces
auto wlan0
#allow-hotplug wlan0
iface wlan0 inet static
       address 192.168.1.1
       netmask 255.255.255.0
       gateway 192.168.1.1
       dns-nameservers 8.8.8.8

/etc/network/if-up.d/dhcp_ap

#!/bin/sh
case $IFACE in
eth0)
  udhcpc -i eth0
  ;;
wlan0)
  hostapd -B /etc/hostapd.conf
  udhcpd
  ;;
esac

/etc/udhcpd.conf

start   192.168.1.101
end     192.168.1.254
interface    wlan0

pidfile /var/run/udhcpd.pid

opt     dns     192.168.1.1
option  subnet  255.255.255.0
opt     router  192.168.1.1
opt     wins    192.168.1.1
option  lease   864000

/etc/hostapd.conf

interface=wlan0
driver=nl80211
ssid=UBC220AP
hw_mode=g
channel=11
wpa=1
wpa_passphrase=UBC220AP
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP CCMP
wpa_ptk_rekey=600
ctrl_interface=/var/run/hostapd

reboot the device

after reboot

You have to setup IP forwarding. There are two different methods to configure.

Method 1 : Modify IP table

iptables -t nat -F
iptables -F
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
iptables -A FORWARD -i wlan0 -o eth0 -j ACCEPT

Method 2 : Set up bridge

Modify /etc/network/interfaces

auto lo br0
iface lo inet loopback
 
# Wired or wireless interfaces
auto eth0
iface eth0 inet dhcp
 
auto eth0:0
iface eth0:0 inet static
       address 192.168.203.220
       netmask 255.255.255.0
 
# Wireless interfaces
auto wlan0
#allow-hotplug wlan0
iface wlan0 inet manual

iface br0 inet static
       bridge_ports wlan0 eth0
       address 192.168.1.1
       netmask 255.255.255.0
       gateway 192.168.1.1
       dns-nameservers 8.8.8.8

Add this line into /etc/hostapd.conf

bridge=br0

Yocto

In this section, we share some tips to use & modify BB files and related configurations for Yocto.

How to delete temporary workspace after build process

By default, the build system preserves the temporary files under the ${TMPDIR}/work directory of each recipe for inspection and possible debugging purposes. If you would rather have these files deleted to save disk space as the build progresses, you can enable rm_work by adding the following to your local.conf file, which is found in the Build Directory.

INHERIT += "rm_work"

To exclude some recipes from having their work directories deleted by rm_work, you can add the names of the recipe or recipes you are working on to the RM_WORK_EXCLUDE variable, which can also be set in your local.conf file. Here is an example:

RM_WORK_EXCLUDE += "busybox glibc"

How to get multi-sources from GIT server

You can assign a name to distinguish the different GIT URIs, and define different destsuffix to save them respectively. Furthermore, to override SRCREV with the name, you can assign different commit id for each GIT branch.

SRC_URI = " \

git://git.allseenalliance.org/gerrit/core/alljoyn.git

protocol=https;branch=${GIT_BRANCH};name=router;destsuffix=git/core/alljoyn \git://git.allseenalliance.org/gerrit/services/base.git

protocol=https;branch=${GIT_BRANCH};name=services;destsuffix=git/services/base \ file: //modify_flags_for_yocto.patch" SRCREV_router = "0d71b216bb3a3cadc615c3eda6f8200093c5e117" SRCREV_services = "403cda579242701d42d2d7c0da308d63a8f46070"

Skip QA check

You can skip the specific QA check for your packages. For details, check the insane.bbclass bbclass in Yocto Project Reference Manual.

INSANE_SKIP_${PN} += "dev-so"

Create BB file to install pre-built SO binaries

Below is an example to add SO binaries into your image. You may need to modify the blue items for your make install path & library name.

SRC_URI = "file://test.tar.gz"

S = "${WORKDIR}/test"

do_install() {
    install -d ${D}/usr/lib
    cp -axr ${S}/lib*.* ${D}/usr/lib/
}

# Avoid package splitting into run-time and debug components
 INHIBIT_PACKAGE_DEBUG_SPLIT = "1"
# Avoid QA Error for already-stripped
 INHIBIT_PACKAGE_STRIP = "1"
# List the files for Package
 FILES_${PN} += "/usr/lib"
# Put all SO files in main rpm package
 FILES_SOLIBSDEV = ""
 INSANE_SKIP_${PN} += "dev-so"
# Set alias name to satisfy runtime dependencies
 RPROVIDES_${PN} = "libtest-1.00.so"

Install Node-RED packages

For Node-RED package installation, you can refer to the example below. Please note this example is based on the imyller's meta-nodejs layer for Node.js infrastructure.

SRC_URI =  "

git://github.com/ADVANTECH-Corp/node-red-contrib-alljoyn.git

protocol=git" SRCREV = "677333b1ed1a26a966c32d98af073d0b9a2b9088" S = "${WORKDIR}/git" # Inherit NPM class inherit npm-install-global # Do node-gyp rebuild in do_install() phase NPM_INSTALL_FLAGS = "--unsafe-perm" # Skip QA check INSANE_SKIP_${PN} = "staticdev"

How to add additional gst-plugins

add new settings in Yocto's conf/local.conf

LICENSE_FLAGS_WHITELIST = "commercial"

COMMERCIAL_AUDIO_PLUGINS ?= " \
gst-plugins-ugly-mad \
gst-plugins-ugly-mpegaudioparse \
"
COMMERCIAL_VIDEO_PLUGINS ?= " \
gst-plugins-ugly-mpeg2dec \
gst-plugins-ugly-mpegstream \
gst-plugins-bad-mpegvideoparse \
"
CORE_IMAGE_EXTRA_INSTALL += " \
gst-plugins-bad-mpegtsdemux \
gst-plugins-bad-fbdevsink \
gst-ffmpeg \
"

overwrite original hash code specified in the recipe x264_git

cat << EOF > meta-advantech/recipes-multimedia/x264/x264_git.bbappend
SRCREV = "ffc3ad4945da69f3caa2b40e4eed715a9a8d9526"
EOF

snapshot verified

How to use Yocto Project Application Development Toolkit (ADT)

(see Setting-up Eclipse Plug-in to cross compile for iMX6 series)

How to add & use Chromium browser

add new settings in conf/local.conf

LICENSE_FLAGS_WHITELIST = "commercial"
CORE_IMAGE_EXTRA_INSTALL += "chromium"

switch "OpenGL ES H/W acceleration" on

edit /usr/share/applications/google-chrome.desktop

[Desktop Entry]
...
Exec=/usr/bin/google-chrome --use-gl=egl %U
...

HTML5 scores

CC2650 Sensortag

CC2650STK – Multi standard supporting Bluetooth low energy, 6LoWPAN, and ZigBee.

These web pages provides gives details for CC2650 :

Set up bluetooth module

1. Enable RFKill configure in kernel

+ CONFIG_RFKILL=y

2. Mount your bluetooth driver

3. Install bluez5 package on Yocto

IMAGE_INSTALL += " bluez5 "

Test Sensor

Enable bluetooth function

hciconfig hci0 up

You can check your bluetooth device by

hcitool dev | grep hci

Scanning sensor by

hcitool lescan

It will find the CC2650 sensortag

LE Scan ...
00:00:00:00:00:00 (unknown)
B0:B4:48:B8:DB:02 CC2650 SensorTag
B0:B4:48:B8:DB:02 CC2650 SensorTag
...

If your device name shows unknown, you have to update this patch to hcitool of bluez5.

You can use gatttool of bluze5 to get sensor data from SensorTag:

Interactive mode:

gatttool -b B0:B4:48:B8:DB:02 -I
connect
char-write-cmd 0x24 01
char-read-hnd 0x21
exit

Command line:

gatttool -b B0:B4:48:B8:DB:02 --char-write --handle 0x24 --value 01
gatttool -b B0:B4:48:B8:DB:02 --char-read --handle 0x21

Set up NodeRed

1. Install sensortag and node-red-node-sensortag by npm on your target board.

npm install sensortag
npm install node-red-node-sensortag

2. Drag the following nodes from the left bar in Node-Red browser interface

sensorTag
Debug

3. Fill the MAC of your SensorTag in the UUID blank

4. Click on the Deploy button.

Reference: Started With Node-RED

Sending Data to Azure IoT Hub by NodeRed

1. To install node-red-contrib-azure-iot-hub on your target board.

npm install -g node-red-contrib-azure-iot-hub

2. Paste the following code into the "Import nodes" dialog

[{"id":"3dc559f2.f78a56","type":"azureiothubregistry","z":"ee5c9c0f.63449","name":"Azure IoT Hub Registry","x":398,"y":449,"wires":"8810a39.828d76"},{"id":"1babf1f6.57f37e","type":"inject","z":"ee5c9c0f.63449","name":"Register Payload","topic":"","payload":"{\"deviceId\": \"device160\"}","payloadType":"json","repeat":"","crontab":"","once":false,"x":168,"y":449,"wires":"3dc559f2.f78a56"},{"id":"8810a39.828d76","type":"debug","z":"ee5c9c0f.63449","name":"Log","active":true,"console":"false","complete":"true","x":678,"y":449,"wires":[]},{"id":"8409d8b1.98cfb8","type":"debug","z":"ee5c9c0f.63449","name":"Log","active":true,"console":"false","complete":"true","x":678,"y":389,"wires":[]},{"id":"48ebe85c.f1a238","type":"azureiothub","z":"ee5c9c0f.63449","name":"Azure IoT Hub","protocol":"mqtt","x":368,"y":389,"wires":"8409d8b1.98cfb8"},{"id":"74099c94.1dc994","type":"inject","z":"ee5c9c0f.63449","name":"Send Payload","topic":"","payload":"{ \"deviceId\": \"device150\", \"key\": \"HostName=AdvTest.azure-devices.net;DeviceId=device150;SharedAccessKey=qkPiSp247kpsrfF6iRFVpTDcnd9Gm2+NzsjPergqyWE=\", \"protocol\": \"mqtt\", \"data\": \"{tem: 25, wind: 20}\" }","payloadType":"json","repeat":"","crontab":"","once":false,"x":158,"y":389,"wires":"48ebe85c.f1a238"}]

3. To Register your SensorTag to your Azure IoT Hub Server

Double click on Register Payload Node to fill following code format in Node-Red browser interface.

For example:

{"deviceId": "device167"}

Double click on Azure IoT Hub Registry Node to fill following code format in Node-Red browser interface.

For example:

HostName=AdvTest.azure-devices.net;SharedAccessKeyName=iothubowner;SharedAccessKey=rsIruTdoINPSjUy7YyF2T1DJ1pTiFY+jrswbPc4ybyk=

4. To send data to Azure IoT Hub

Double click on Send Payload Node to fill information followed payload format in Node-Red browser interface.

For example:

{
 "deviceId": "device143",
 "key": "LLgyZaqAwYXk1uidzM27aO1YIA76fjv55Zs7unExFz8=",
 "protocol": "http",
 "data": "{tem: 25, wind: 20}"
}

Double click on Azure IoT Hub Node to fill information

For example:

Name: Azure IoT Hub
Protocol: http
Hostname: AdvTest.azure-devices.net

Reference: node-red-contrib-azure-iot-hub

Note:

1. If it can not connect to Azure IoT Hub, you maybe reinstall node-gyp.

npm install -g node-gyp

2. Check status of connection with Azure IoT Hub

DeviceExplorer

Sending Data to Azure IoT Hub by tools of Azure IoT SDK

We suggest all operations of compiling AZure IoT Hub on Docker Images because it will be updated some packages of OS after the following steps,

Get source code

git clone  --recursive https://github.com/azure/azure-iot-sdk-c.git

Compilation

1. Upgrade CMake

sudo add-apt-repository ppa:kalakris/cmake
sudo apt-get update

2. Set up environment

sudo ./build_all/linux/setup.sh

3. To create one new build environment of Yocto

For example:

EULA=1 DISTRO=fsl-imx-x11 MACHINE=imx6qrom7420a1 source fsl-setup-release.sh -b build-x11

4. Create cmake file, yocto_1.7.cmake, depended on your Yocto SDK environment in ./buill_all/linux

# compiler
include(CMakeForceCompiler)

# this is required
SET(CMAKE_SYSTEM_NAME Linux)
SET(CMAKE_SYSTEM_PROCESSOR arm)
SET(CMAKE_SYSTEM_VERSION 1)

SET(CMAKE_SYSROOT /opt/poky/1.7/sysroots/cortexa9hf-vfp-neon-poky-linux-gnueabi)

cmake_force_c_compiler(/opt/poky/1.7/sysroots/x86_64-pokysdk-linux/usr/bin/arm-poky-linux-gnueabi/arm-poky-linux-gnueabi-gcc GNU)
cmake_force_cxx_compiler(/opt/poky/1.7/sysroots/x86_64-pokysdk-linux/usr/bin/arm-poky-linux-gnueabi/arm-poky-linux-gnueabi-g++ GNU)
# sysroot location
set(MYSYSROOT /opt/poky/1.7/sysroots/cortexa9hf-vfp-neon-poky-linux-gnueabi)
# compiler/linker flags
add_definitions("--sysroot=${MYSYSROOT}")
# compiler/linker flags
add_definitions("--sysroot=${MYSYSROOT}")
set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -march=armv7-a -std=gnu99 -mthumb-interwork -mfloat-abi=hard -mfpu=neon -mtune=cortex-a9 --sysroot=${MYSYSROOT}" CACHE INTERNAL "" FORCE)
set(CMAKE_C_LINK_FLAGS "${CMAKE_C_LINK_FLAGS} -std=gnu99 -march=armv7-a -mthumb-interwork -mfloat-abi=hard -mfpu=neon -mtune=cortex-a9 --sysroot=${MYSYSROOT}" CACHE INTERNAL "" FORCE)
set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -std=gnu99 -march=armv7-a -mthumb-interwork -mfloat-abi=hard -mfpu=neon -mtune=cortex-a9 --sysroot=${MYSYSROOT}" CACHE INTERNAL "" FORCE)
set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -std=gnu99 -march=armv7-a -mthumb-interwork -mfloat-abi=hard -mfpu=neon -mtune=cortex-a9 --sysroot=${MYSYSROOT}" CACHE INTERNAL "" FORCE)
# cmake built-in settings to use find_xxx() functions
set(CMAKE_FIND_ROOT_PATH ${MYSYSROOT})
set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)

5. modify connectionString of your SensorTag in ./iothub_client/samples/iothub_client_sample_http/iothub_client_sample_http.c

For example:

static const char* connectionString = "HostName=AdvTest.azure-devices.net;DeviceId=device143;SharedAccessKey=LLgyZaqAwYXk1uidzM27aO1YIA76fjv55Zs7unExFz8=";

6. Compile by

cd ./build_all/linux/
sudo ./build.sh --toolchain-file yocto_1.7.cmake

7. The output file is iothub_client_sample_http in ./cmake/iotsdk_linux/iothub_client/samples/iothub_client_sample_http/

Bluetooth

Install bluetooth tool on Debial/Ubuntu

sudo apt-get update
sudo apt-get install bluetooth blueman bluez bluez-tools

Connect with smart phone

Connect with laptop

Bluetooth_Yocto

Test bluetooth tool on Yocto

GPS

Support on APQ8016 project

First install some packages (reference from "Using the onboard GPS" in Linaro)

sudo apt-get install gpsd-clients gnss-gpsd

Start service on DSP

systemctl start gpsd.socket
systemctl start gpsd
systemctl start qdsp-start
systemctl start gnss-gpsd

Using gpsd client to monitor

gpsmon:

If you want to analyze NMEA sentences, you can reference information on NMEA

Touch

Support the Zytronic TOUCH on i.MX6 Yocto Liunx

Download the SWAP and Calibration Tools for zytronic.co.uk. http://zytronic.co.uk/support/downloads/

Linux Kernel : Need to enable CONFIG_HID_MULTITOUCH config

CONFIG_HID_MULTITOUCH=y

Step1 : For your application, you need to SWAP or Calibration your panel.

Step2 : Download the tools from http://zytronic.co.uk/support/downloads/ .

Step3 : In ZXY100 32 Input Controller Drivers, choose your version (win7 ,win8 or win10).

Step4 : Unzip the "Windows-01-03-2016" folder.

Step4 : Plug into the usb.

Step5 : Run Zyconfig (Administrator) in ZyConfig_Tool_02.07.29_04.07.16.

Step6: If your application need to swap the x and y axes, your can choose the (Swap X-Y axes).

RT-Patch

Description

Only support to patch patch_4.1.15_rt18_patch files on i.MX6 Liunx Yocto 2.1.

Download file: File:RT Patch.zip

Linux OS version: Yocto 2.1 (Krogoth, L4.1.15_2.0.0_ga)

Patch patch_4.1.15_rt18_patch files to kernel code

Implementation Steps

Set up the compiler environment. You can refer following URL to install tool chain

Setting_up_SDK

Assuming the installation tool chain position is as follows

/opt/poky/2.1/environment-setup-cortexa9hf-neon-poky-linux-gnueabi

Generate kernel image (zImage)

Step 1: Enter the directory of kernel source code

$ cd linux-imx6/

Step 2: Patch two patch files to kernel code

$ patch -p1 -i 0001-patch-4.1.15-rt18.patch
$ patch -p1 -i 0002-add-defconfig-and-fix-compiler-failed-and-fix-error.patch

Step 3: Initialize the building environment

$ source /opt/poky/2.1/environment-setup-cortexa9hf-neon-poky-linux-gnueabi

Step 4: Set the configuration of kernel

$ make imx_v7_adv_defconfig

Step 5: Build kernel image

$ make -j 4 zImage

After building kernel image, it will be generated kernel image (zImage) in "arch/arm/boot"

Step 6: Copy kernel image (zImage) to USB disk

Insert the USB disk to the device and boot on the device

After login the device, enter to USB disk directory. For Example:

$ cd /run/media/sda1

Remove kernel image (zImage) from eMMC

$ rm /run/media/mmcblk0p1/zImage
$ sync

Copy kernel image (zImage) to eMMC

$ cp zImage /run/media/mmcblk0p1/
$ sync

Restart the device, the kernel image has RT feature.

Real-Time Kernel Performance

cyclictest is a realtime benchmark tool. It can determine the realtime performance of your new preempt-rt patched kernel. For more detail about cyclictest, please refer below link

Cyclictest Link URL

I provide cyclictest test tool for i.MX6 in RT_Patch_and_Test_Tool.zip file

Copy cyclictest test tool to the device

Below command is an example of using cyclictest

$ ./cyclictest -p 90 -t5 -n

The snapshot results show performance comparisons of non-RT patch and RT patch. The final column displays the maximum latency of real-time task.

Linux_Yocto_4.1.15 (Non real-time patch)

Linux_Yocto_4.1.15-rt18 (real-time patch)

The RT kernel better performance than non-RT kernel in above results.

USB-Boot

Description

Only support USB boot function on i.MX6 Liunx Yocto 2.1.

Linux OS version: Yocto 2.1 (Krogoth, L4.1.15_2.0.0_ga)

Implementation Steps

For example: Add USB boot function to UBC-220 project

Modify in uboot-imx6/include/configs/mx6ubc220.h

@@ -10,6 +10,9 @@
 #define __MX6QSABRESD_CONFIG_H
 
 #ifdef CONFIG_SPL
+#define CONFIG_USB_BOOT
+#define CONFIG_SPL_LIBGENERIC_SUPPORT
+#define CONFIG_SPL_LIBDISK_SUPPORT
 #define CONFIG_SPL_LIBCOMMON_SUPPORT
 #define CONFIG_SPL_MMC_SUPPORT
 #include "imx6_spl_advantech.h"
@@ -86,7 +89,7 @@
 #define CONFIG_USB_ETHER_ASIX
 #define CONFIG_MXC_USB_PORTSC          (PORT_PTS_UTMI | PORT_PTS_PTW)
 #define CONFIG_MXC_USB_FLAGS           0
-#define CONFIG_USB_MAX_CONTROLLER_COUNT        1 /* Enabled USB controller number */
+#define CONFIG_USB_MAX_CONTROLLER_COUNT        2 /* Enabled USB controller number */
 #endif

Customized GPIO Function

Description

Only support USB boot function on i.MX6 Liunx Yocto 2.1.

Linux OS version: Yocto 2.1 (Krogoth, L4.1.15_2.0.0_ga)

For example: We implement a customized GPIO function for RSB-4411. We setting 20 GPIO pings.

Input-High GPIO: GPIO1,GPIO3,GPIO5,GPIO7,GPIO9,GPIO11,GPIO13,GPIO15,GPIO17,GPIO19

Output-Low GPIO: GPIO2,GPIO4,GPIO6,GPIO8,GPIO10,GPIO12,GPIO14,GPIO16,GPIO18,GPIO20

Download file: Customized_GPIO_Function_Patch_Files.zip

Linux Software Features

Contents

Console

How to enable framebuffer console

How to change debug console port

Ltib

Ltib

Yocto

How to disable debug console

Ltib

Device Tree

File System

NTFS

Fonts

Chinese Font

GStreamer

Play Video

Audio Information

Frame Buffer Information

Play Video Command

Play Video Command On Yocto 1.5

Play Video Command On Yocto 1.7

Play Video Command On Yocto 1.8

SMPTE color bar

video rotation

webcam

realtime video

take one snapshot

show one snapshot

network streaming

RTSP(unicast)

RTP(multicast)

Java

Linux Kernel

Get kernel configs from running OS

Debug kernel panic and oops

Dynamic Voltage and Frequency Scaling (DVFS)

CPUFreq & OPP

CPU Governor

NFS

boot up to Linux

boot up to U-Boot

OpenCV

Python

Qt

Setting-up QtCreator to cross compile for iMX6 series]

Writing the Qt application with displaying Chinese

SSH

TFTP

boot up to Linux

WiFi AP mode

before buildinging sdcard image

after booting-up

after reboot

Yocto

How to delete temporary workspace after build process

How to get multi-sources from GIT server

Skip QA check

Create BB file to install pre-built SO binaries

Install Node-RED packages

How to add additional gst-plugins

How to use Yocto Project Application Development Toolkit (ADT)

How to add & use Chromium browser

CC2650 Sensortag

Set up bluetooth module

Test Sensor

Set up NodeRed

Sending Data to Azure IoT Hub by NodeRed

Sending Data to Azure IoT Hub by tools of Azure IoT SDK

Bluetooth

Bluetooth_Yocto

GPS

Touch

RT-Patch

Description

Implementation Steps

Real-Time Kernel Performance

USB-Boot

Description

Implementation Steps