CMEM Range Overlaps Kernel Physical Problem

amit pandya

Hello All,

I am working with DM365 DVSDK 2.10.

In the loadmodules.sh that comes along with DVSDK, I could see the followng for CMEM

insmod cmemk.ko phys_start=0x85000000 phys_end=0x88000000 pools=6x4096,2x8192,1x11908,2x13184,1x2697152,6x4096,1x30720,3x81920,1x3185664,64x56,1x320,1x640,1x81920,1x6650880,2x608,1x296,1x28,2x24,23x1548288,1x154288 allowOverlap=1 phys_start_1=0x00001000 phys_end_1=0x00008000 pools_1=1x28672

with the above, I am getting the following error when CMEM is inserted

cmem initialized 20 pools between 0x85000000 and 0x88000000
CMEM Range Overlaps Kernel Physical - allowing overlap
CMEM phys_start (0x1000) overlaps kernel (0x80000000 -> 0x85000000)
ioremap_nocache(0x1000, 28672)=0xc5888000
no remaining memory for heap, no heap created for memory block 1
cmem initialized 1 pools between 0x1000 and 0x8000

However, when I am modifying the argument for CMEM as

The above error is no more observed.

Please tell me the significance of the following and why is created and usage of this 28k block of memory

allowOverlap=1 phys_start_1=0x00001000 phys_end_1=0x00008000 pools_1=1x28672

Thanks.

over 15 years ago

0 Vincent W. over 15 years ago

TI__Genius 12865 points

Hi Amit,

CMEM is a contiguous memory allocator that can manage up to two separate memory blocks in physical memory. In your case, the first is bounded by phys_start=0x85000000 phys_end=0x8800000, and the second is bounded by phys_start_1=0x00001000 phys_end_1=0x00008000 . Memory pools can be defiined in these memory areas, and pools_1 defines the pools that are allocated out of the second memory block. Some basic information on CMEM can be found there: http://processors.wiki.ti.com/index.php/CMEM_Overview

It is important for the memory block(s) managed by CMEM to not overlap with Linux kernel memory. The error you are getting is due to the fact that one of the memory regions overlaps with the kernel memory. Unless you are running out of CMEM memory, there is no need to define the second memory block, and the fix you are doing is fine.

'allowOverlap' is explained here: http://processors.wiki.ti.com/index.php/Codec_Engine_FAQ#Why_do_I_need_to_use_CMEM.27s_allowOverlap.3D1_.27insmod.27_option_even_though_the_Linux_kernel_doesn.27t_actually_use_the_physical_memory_range_that_I_am_specifying.3F

Best regards,

Vincent

0 Robert Tivy over 15 years ago in reply to Vincent W.

TI__Mastermind 18260 points

Vincent said:

It is important for the memory block(s) managed by CMEM to not overlap with Linux kernel memory. The error you are getting is due to the fact that one of the memory regions overlaps with the kernel memory. Unless you are running out of CMEM memory, there is no need to define the second memory block, and the fix you are doing is fine.

'allowOverlap' is explained here: http://processors.wiki.ti.com/index.php/Codec_Engine_FAQ#Why_do_I_need_to_use_CMEM.27s_allowOverlap.3D1_.27insmod.27_option_even_though_the_Linux_kernel_doesn.27t_actually_use_the_physical_memory_range_that_I_am_specifying.3F

The 2nd memory block is important for codecs. Its definition is also explained in the CE FAQ entry that Vincent provided, and the 'allowOverlap=1' is needed for it to be defined successfully.

Regards,

- Rob

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CMEM Range Overlaps Kernel Physical Problem