RAM size in Linux

[jotes]

Hello!

How to reduce amount of memory which can be accessed by Linux? Adding  "memory" part to devicetree or "mem=" argument to the kernel command line doesn't work. Is there any other way? I am using IMX6Q with the following software: buildroot-2015.11.1, linux-imx6-boundary-imx_3.14.38_6qp_ga-pass1, u-boot-2015.07.

[igorpadykov]

Hi jotes

for setting memory size in linux one can look at

http://stackoverflow.com/questions/13484016/setting-limit-to-total-physical-memory-available-in-linu...

or try to set in uboot/include/configs/board_file parameter #define PHYS_SDRAM_SIZE

Best regards

igor

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[jotes]

After setting:

#define PHYS_SDRAM_SIZE (1u * 480 * 1024 * 1024)

u-boot still shows:

U-Boot 2015.07 (Apr 26 2016 - 13:05:59 +0200)

CPU:   Freescale i.MX6Q rev1.5 at 792MHz

CPU:   Industrial temperature grade (-40C to 105C) at 53C

Reset cause: POR

Board: MX6

I2C:   ready

DRAM:  512 MiB

PMIC:  PFUZE100 ID=0x10

MMC:   FSL_SDHC: 0, FSL_SDHC: 1

Using default environment

In:    serial

Out:   serial

Err:   serial

Hit any key to stop autoboot:  0

Kernel image @ 0x12000000 [ 0x000000 - 0x61dcb0 ]

## Loading init Ramdisk from Legacy Image at 12c00000 ...

   Image Name:

   Image Type:   ARM Linux RAMDisk Image (gzip compressed)

   Data Size:    31276561 Bytes = 29.8 MiB

   Load Address: 00000000

   Entry Point:  00000000

   Verifying Checksum ... OK

## Flattened Device Tree blob at 18000000

   Booting using the fdt blob at 0x18000000

   Loading Ramdisk to 2d785000, end 2f558e11 ... OK

   Loading Device Tree to 2d779000, end 2d784cc2 ... OK