[RFT PATCH] ARM64: dts: meson-gxbb: Add reserved memory zone and usable memory range

Heinrich Schuchardt xypron.glpk at gmx.de
Thu Dec 22 02:02:10 PST 2016

On 12/14/2016 10:52 AM, Neil Armstrong wrote:

> Hi Heinrich,
> Thanks for testing and for the report,
> we are still struggling into finding what are these zones and how to label them correctly.
> We need to identify the zones on all boards, the patch I provided works on a non-odroid-c2 and gxm and gxl boards.
> Neil
Hello Neil,

the configuration below works for me on the Hardkernel Odroid C2.

ramoops is needed for CONFIG_PSTORE_RAM.
Debian Stretch has CONFIG_PSTORE_RAM=m. Same is true for Fedora.
I have chosen the address arbitrarily. To accommodate 512 MB boards we
would have to put it below 0x20000000.
The size parameters are the same as in hisilicon/hi6220-hikey.dts and

linux,cma is used for contiguous memory assignment. I have taken the
align parameter from arm-src-kernel-2016-08-18-26e194264c.tar.gz
provided by Amlogic at
http://openlinux.amlogic.com:8000/download/ARM/kernel/ .
See Documentation/DMA-API.txt for the usage of align.
They use the same value 0x400000 for all GXBB boards.
So we want to put this zone into meson-gxbb.dtsi.

secmon is used by drivers/firmware/meson/meson_sm.c.
Amlogic uses the same address range for all 64bit boards.

	memory at 0 {
		device_type = "memory";
		linux,usable-memory = <0x0 0x1000000 0x0 0x7f000000>;

	reserved-memory {
		#address-cells = <0x2>;
		#size-cells = <0x2>;

		ramoops at 0x23f00000 {
			compatible = "ramoops";
			reg = <0x0 0x23f00000 0x0 0x100000>;
			record-size = <0x20000>;
			console-size = <0x20000>;
			ftrace-size = <0x20000>;

		secmon: secmon {
			compatible = "amlogic, aml_secmon_memory";
			reg = <0x0 0x10000000 0x0 0x200000>;

		linux,cma {
			compatible = "shared-dma-pool";
			size = <0x0 0xbc00000>;
			alignment = <0x0 0x400000>;

Best regards

Heinrich Schuchardt

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