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get panic in configure DDR to 2G BYTE

Other Parts Discussed in Thread: 4460, 4430

Dear SIR
We use omap4470 and 4AI.1.4P1 software.
We try to enable 2GByte DDR in our system.
system get panic when we configure to 2Gbyte.
EMIF register setting seem good and we can see following log in uboot.
----------------------------------------------------------
U-Boot 1.1.4 (Jun 22 2012 - 15:59:27)

Load address: 0x80e80000
DRAM: 2048 MB
Flash: 0 kB
In: serial
Out: serial
Err: serial
----------------------------------------------------

we do following change in kernel code.
1.omap4_ion.h //arch/arm/mach-omap2
#define PHYS_ADDR_SMC_MEM (0x80000000 + SZ_2G - PHYS_ADDR_SMC_SIZE)

2.blaze_defconfig.h
CONFIG_CMDLINE="console=ttyO2,115200n8 mem=2G vmalloc=768M androidboot.console=ttyO2 omap_wdt.timer_margin=30"

but system always panic log as below
-------------------------------------------------------------------------
CPU: ARMv7 Processor [412fc09a] revision 10 (ARMv7), cr=10c5387d
CPU: VIPT nonaliasing data cache, VIPT aliasing instruction cache
Machine: OMAP4 blaze board
*****TEST: size 0x2000000 addr0x0.
<6>Reserving 33554432 bytes SDRAM for VRAM
Memory policy: ECC disabled, Data cache writealloc
*****TEST: size 0x1000 addr0x0.
<0>Kernel panic - not syncing: ERROR: Failed to allocate 0x1000 bytes below 0x0.
--------------------------------------------------------------------------
kernel boot in 1Gbyte DDR setting is fine by modify blaze_defconfig.h
CONFIG_CMDLINE="console=ttyO2,115200n8 mem=1G vmalloc=768M androidboot.console=ttyO2 omap_wdt.timer_margin=30"

kernel panic only occur when we change to 2G setting
CONFIG_CMDLINE="console=ttyO2,115200n8 mem=2G vmalloc=768M androidboot.console=ttyO2 omap_wdt.timer_margin=30"

Please help:
1.Maybe DDR change from 1Gbyte to 2GByte need modify more code.Please adivce.
2.Where to configure system memory allocatioin table.
Thank you for taking the time to help.

  • Sam,

    The default configuration in the Linux kernel, and in the 4AI.1.x releases, splits the available 4GB address space into a 3GB virtual memory space for user processes and a 1GB virtual memory space for the kernel.  Do you plan to change this split?  I believe you will be limited to 1GB in the kernel (actually 896 MB because 128 MB of the address space is occupied by kernel data structures).

    Regards,
    Gina 

  • Hi Gina,

    sorry for poor description.

    The SDRAM in 4470 tablet2 is 1GB and 4AI.1.4.x also setting system ddr to 1GB.after android system boot.we can see 6XXMB ram in setting .

    Now we have new board and SDRAM is 2GB .We need change code .the purpose is let  android system have  more RAM than 6XXMB (maybe16xxMB ) .

    Can you help to point out where need to modify.

    thanks

    SAM

  • Hi Sam,

    Sorry for my delay.  

    Could you try without any "mem=" in the bootargs?  In the newer releases, including 4AI.1.4 I believe, the bootloader will pass the ATAG, including the memory descriptor, to the kernel.  Specifying a "mem=" in the bootargs will override whatever is being provided by the bootloader, which is not normally necessary. 

    Also, make sure to modify the kernel board file appropriately; in /arch/arm/mach-omap2/board-4430sdp.c, we have:

    1031 /*
    1032  * LPDDR2 Configuration Data for 4430/4460 SOMs:
    1033  * The memory organization is as below :
    1034  *      EMIF1 - CS0 -   2 Gb
    1035  *              CS1 -   2 Gb
    1036  *      EMIF2 - CS0 -   2 Gb
    1037  *              CS1 -   2 Gb
    1038  *      --------------------
    1039  *      TOTAL -         8 Gb
    1040  *
    1041  * Same devices installed on EMIF1 and EMIF2
    1042  */
    1043 static __initdata struct emif_device_details emif_devices = {
    1044         .cs0_device = &lpddr2_elpida_2G_S4_dev,
    1045         .cs1_device = &lpddr2_elpida_2G_S4_dev
    1046 };
    You will need to update this based on the configuration of your particular DDR part.
    Regards,
    Gina
  • Sam,

    Is this working for you now?

    Regards,
    Gina 

  • Dear Gina,

    Sorry for forget to response this item.

    this is work for me .

    thanks.

    SAM