imx8dx 512M ddr for reserved-memory

[songhongliang]

HI，

I am using imx8dx + 512M RAM,now the reserved-memory for cam  gpu How to set the size.

original:

imx8dx-mek.dts file:

linux,cma {
compatible = "shared-dma-pool";
reusable;
size = <0 0x14000000>;
alloc-ranges = <0 0x98000000 0 0x14000000>;
linux,cma-default;
};

&imx8_gpu_ss {
reg = <0x80000000 0x40000000>, <0x0 0x08000000>;
reg-names = "phys_baseaddr", "contiguous_mem";
};

imx8x-mek.dtsi file:

reserved-memory {
#address-cells = <2>;
#size-cells = <2>;
ranges;

/*
* 0x8800_0000 ~ 0x8FFF_FFFF is reserved for M4
* Shouldn't be used at A core and Linux side.
*
*/
m4_reserved: m4@0x88000000 {
no-map;
reg = <0 0x88000000 0 0x8000000>;
};

rpmsg_reserved: rpmsg@0x90000000 {
no-map;
reg = <0 0x90200000 0 0x200000>;
};

decoder_boot: decoder-boot@84000000 {
reg = <0 0x84000000 0 0x2000000>;
no-map;
};

encoder_boot: encoder-boot@86000000 {
reg = <0 0x86000000 0 0x200000>;
no-map;
};

decoder_rpc: decoder-rpc@0x92000000 {
reg = <0 0x92000000 0 0x200000>;
no-map;
};

encoder_rpc: encoder-rpc@0x92200000 {
reg = <0 0x92200000 0 0x200000>;
no-map;
};
encoder_reserved: encoder_reserved@94400000 {
no-map;
reg = <0 0x94400000 0 0x800000>;
};
/* global autoconfigured region for contiguous allocations */
linux,cma {
compatible = "shared-dma-pool";
reusable;
size = <0 0x3c000000>;
alloc-ranges = <0 0x96000000 0 0x3c000000>;
linux,cma-default;
};
};

reserved-memory {
#address-cells = <2>;
#size-cells = <2>;
ranges;

vdev0vring0: vdev0vring0@90000000 {
compatible = "shared-dma-pool";
reg = <0 0x90000000 0 0x8000>;
no-map;
};

vdev0vring1: vdev0vring1@90008000 {
compatible = "shared-dma-pool";
reg = <0 0x90008000 0 0x8000>;
no-map;
};

vdev1vring0: vdev1vring0@90010000 {
compatible = "shared-dma-pool";
reg = <0 0x90010000 0 0x8000>;
no-map;
};

vdev1vring1: vdev1vring1@90018000 {
compatible = "shared-dma-pool";
reg = <0 0x90018000 0 0x8000>;
no-map;
};

vdevbuffer: vdevbuffer {
compatible = "shared-dma-pool";
reg = <0 0x90400000 0 0x100000>;
no-map;
};
};

thanks,

[igorpadykov]

Hi songhongliang

for cma size there is no some formula, it can be found experimentally for

each configuration, try some heavy load use cases for example described in

AN12338  sect.4.2.2. Kanzi

i.MX 8QuadXPlus Power Consumption Measurement

Best regards
igor

[songhongliang]

HI,

For example, a simple QT application for automotive instrumentation, using LVDS display, how much GPU reserved memory needs to be set

Thanks

[songhongliang]

HI，

I use one lvds lcd and three AHD camera。

thanks!