AmLogic s805x GXL SoC board bring up

One of my previous projects was the bring-up of a newly developed board based on the AmLogic s805x (GXL) SoC. I will describe what the bring-up process looks like and what was tested, and we will also take a look at how flashing an AmLogic board works on the GXL platform (G12B and newer are very similar).

This is our board:

The first stage of a bring-up is to build an image for the reference board. In our case that is p241, and we took the a113 sources for it. Building the p241 reference sources:

Build the image

# You need arm-linux-gnueabihf-gcc and aarch64-linux-gnu-gcc to be installed in system toolchains
$ sudo apt-get install zlib1g zlib1g-dev
$ source buildroot/build/setenv.sh
# Choose "mesongxl_p241_32_kernel49" // option 37
$ ln -s aml-4.9 kernel/aml-3.14
$ ln -s aml-4.9 hardware/aml-3.14
$ make

Once the process is complete, everything ends up in output/mesongxl_p241_32_kernel49/images, with the following parts:

• boot.img — the kernel
• u-boot.bin — the U-Boot image
• rootfs.ext2 — the root filesystem
• gxl_p241_v2_1g_buildroot.dtb — the DTB (flashed to the dtb partition through dtb.img)

Flash the image

The second step is flashing everything to the MMC. The easiest way is to use the AmLogic flashing tool, the AmLogic USB Burning Tool:

You have to select the full image you built.

If everything is fine, you will see U-Boot loading and the kernel starting after it:

Control and test the LEDs

In our case everything booted, but some parts needed additional verification. The first one was the Ethernet LEDs, which did not work. How do we blink them from the kernel?

That’s pretty easy — drive the Ethernet LEDs through their GPIO state:

# It can be re enabled manually using control GPIO commands:
# GPIO (401 + 14) - green
# GPIO (401 + 15) - yellow

Z8# echo 415 >/sys/class/gpio/export
Z8# echo 416 >/sys/class/gpio/export
Z8# echo out >/sys/class/gpio/gpio415/direction
Z8# echo out >/sys/class/gpio/gpio416/direction
Z8# echo 1 >/sys/class/gpio/gpio415/value
Z8# echo 1 >/sys/class/gpio/gpio416/value

We set the GPIO direction and write 1 to the value.

Fix the battery-backed clock by enabling the DS1307 driver

The second problem was that the battery clock did not work out of the box. Let’s enable it. We use a DS1307 controller, so let’s apply the following patch:

diff --git a/arch/arm/configs/meson64_a32_defconfig b/arch/arm/configs/meson64_a32_defconfig
index 8e7d5648501a..446e1973c554 100644
--- a/arch/arm/configs/meson64_a32_defconfig
+++ b/arch/arm/configs/meson64_a32_defconfig
@@ -593,3 +593,4 @@ CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE=y
 CONFIG_X509_CERTIFICATE_PARSER=y
 CONFIG_CRC_T10DIF=y
 CONFIG_CRC7=y
+RTC_DRV_DS1307=y
diff --git a/arch/arm64/boot/dts/amlogic/gxl_p241_v2_1g_buildroot.dts b/arch/arm64/boot/dts/amlogic/gxl_p241_v2_1g_buildroot.dts
index bf77a30db461..ba45803a8552 100644
--- a/arch/arm64/boot/dts/amlogic/gxl_p241_v2_1g_buildroot.dts
+++ b/arch/arm64/boot/dts/amlogic/gxl_p241_v2_1g_buildroot.dts
@@ -1359,3 +1359,14 @@
        delay_control = <0x15>;
        ssctl = <0>;
 };
+
+&i2c0 {
+       status = "okay";
+       pinctrl-0 = <&a_i2c_master>;
+       pinctrl-names = "default";
+
+       rtc: rtc@68 {
+               compatible = "dallas,ds1340";
+               reg = <0x68>;
+       };
+};
diff --git a/arch/arm64/configs/meson64_defconfig b/arch/arm64/configs/meson64_defconfig
index 968ee40827bc..1367a6cebd19 100644
--- a/arch/arm64/configs/meson64_defconfig
+++ b/arch/arm64/configs/meson64_defconfig
@@ -617,3 +617,4 @@ CONFIG_CRYPTO_GHASH_ARM64_CE=y
 CONFIG_CRYPTO_AES_ARM64_CE_BLK=y
 CONFIG_CRC_T10DIF=y
 CONFIG_CRC7=y
+RTC_DRV_DS1307=y

And now let’s test it with i2cdump:

i2cdump -f -y 0 0x68

Sound testing

We did this with speaker-test, which is part of the image:

# via audio jack
Z8# speaker-test -c2 -D hw:0,0
# via hdmi SPDIF
Z8# speaker-test -c2 -D hw:0,1

Load testing

Let’s load the system to 100%. One of the most effective ways is with bzip2:

Z8# (dd if=/dev/urandom | bzip2 -9 >> /dev/null &); (dd if=/dev/urandom | bzip2 -9 >> /dev/null &); (dd if=/dev/urandom | bzip2 -9 >> /dev/null &); (dd if=/dev/urandom | bzip2 -9 >> /dev/null &)

Let’s increase the load further with more bzip2 processes plus hardware-decoded playback:

Z8# (dd if=/dev/urandom | bzip2 -9 >> /dev/null &); (dd if=/dev/urandom | bzip2 -9 >> /dev/null &); (dd if=/dev/urandom | bzip2 -9 >> /dev/null &); (dd if=/dev/urandom | bzip2 -9 >> /dev/null &)
Z8# (dd if=/dev/urandom | bzip2 -9 >> /dev/null &); (dd if=/dev/urandom | bzip2 -9 >> /dev/null &); (dd if=/dev/urandom | bzip2 -9 >> /dev/null &); (dd if=/dev/urandom | bzip2 -9 >> /dev/null &)
Z8# gst-launch-1.0 filesrc location=videoplayback.mp4 ! qtdemux ! h264parse ! amlvdec ! amlvsink

## Verify with top
Z8# top

The maximum power consumption we measured is 0.46 A.

Hardware accelerated decoding

Hardware accelerated H264 video

Z8# gst-launch-1.0 filesrc location=videoplayback.mp4 ! qtdemux ! h264parse ! amlvdec ! amlvsink

gst-launch-1.0 starts decoding the video, so you can watch the decoded stream. If the screen is occupied by the browser, free it first:

Z8# killall chrome

Hardware accelerated audio

Z8# gst-launch-1.0 filesrc location=1.mp3 ! mpegaudioparse ! amladec ! audioconvert ! amlasink

Temperature measurements

Z8# cat /sys/class/thermal/thermal_zone*/temp

Play an audio file

Z8# aplay -D hw:0,0 -c2 -f cd flower_ok.wav

Mounting USB drives

Z8# mkdir /media/flash
Z8# mount -t vfat /dev/sda /media/flash
Z8# cd /media/flash

HDMI tests

We simply plugged a monitor in to verify that everything works :).