I am using panda board.In this processor is omap4430.
I am right now little bit confused regarding the memory map .
In OMAP4430 Multimedia Device, Silicon Revision 2.x, Texas Instruments OMAP™ Family of ProductsVersion R and point 2.2 has mentioned that L1 is 4 GB which is having q0,q1,q2 and q3 quarters.
Can you tell me this L1 is shared by Cortex-A9 MPU, Cortex™-M3 MPU, and the digital signal processor (DSP) subsystems.
Or individually it is separate for each cortex a9 (as there are 2 MPU)
Please let me know .
The Level 1 (L1) memory is cache memory local to each module, it is not shared between them.
You can see that in the 4430 TRM:
1.3.1 Cortex-A9 MPU Subsystem DescriptionThe Cortex-A9 MPU subsystem integrates the following submodules:• ARM Cortex-A9 MPCore– Two ARM Cortex-A9 central processing units (CPUs)– ARM Version 7 ISATM: Standard ARM instruction set plus Thumb®-2, Jazelle® RCT and JazelleDBX JavaTM accelerators– NeonTM SIMD coprocessor and VFPv3 per CPU– Interrupt controller (Cortex-A9 MPU INTC) with up to 128 interrupt requests– One general-purpose timer and one watchdog timer per CPU– Debug and trace features– 32-KB instruction and 32-KB data level 1 (L1) caches per CPU• Shared 1-MB level 2 (L2) cache• 48 KB bootable ROM• Local power, reset, and clock managment (PRCM) module• Emulation features• Digital phase-locked loop (DPLL)1.3.3 Cortex-M3 MPU Subsystem DescriptionThe Cortex-M3 MPU subsystem includes the following components:• Two Cortex-M3 CPUs: One for SIMCOP control, and the other for RTOS, ISP, and display subsystemcontrol• ARMv7-M and Thumb-2 instruction set architecture• Dedicated INTC with up to 64 physical interrupt events• Two-level memory subsystem hierarchy– L1• 32-KB shared cache memory– L2 ROM + RAM• 64-KB RAM• 16-KB bootable ROM• Cortex-M3 system bus directly connected to the ISS interconnect• MMU for address translation• Integrated power management• Emulation feature embedded in the Cortex-M3For communication between A9, M3 and DSP there is the L3 interconector
Thanks Israel Cepeda for your reply.
I got clear with your answer partially.
As mentioned in TRM 2.2 that is-
The system memory mapping is flexible, with two levels of granularity for target address space allocation:• L1: Four quarters are labeled Q0, Q1, Q2, and Q3. Each quarter corresponds to a 1-GB address space(total address space is 4GB)..
L2: Each quarter is devided into 8 blocks of 32 MB each
I come to know that L1(not cache memory) having four quarters that is Q0(1GB) is the BOOT SPACE/GPMC ,Q2 AND Q3 is DDR address space .
But my doubt is that whether the Q1 mentioned here is the part of all three subsystems Cortex-A9 MPU, Cortex™-M3 MPU, and DSP subsystems or it is local to each module ?
Its accessible by all three subsystems A9,M3 and DSP. Its not local to any single module.
Ok, so you are only talking about the L3 Memory Space Mapping..
That is 4GB as you mentioned, if you want to see the details how it is divided you can see: Table 2-1. Global Memory Space Mapping
I don't now if one of the reserved are the memory for the subsystems you mentioned, but looking in the Interconnect part I found:
13.1.2 Architecture OverviewThe device memory hierarchy includes four levels:• Level 1 (L1) is internal to the central processing units (CPUs). It concerns data exchange with the internal Level1 cache memory subsystem,and it is the closest memory to the microprocessor unit (MPU) core and the IVAHD core.• Level 2 (L2) is included in the IVAHD subsystem and the MPU subsystem.• The chip-level interconnect consists of one level 3 (L3) interconnect and four level 4 (L4) interconnects. It enables communication among the modules and subsystems in the device.Figure 13-1 shows an overview of the L3 and L4 interconnect architecture.So for those modules seems to be local, and can be access using L3.
So going to the original question, I think there is no direct access between L1 on those subsystems like in ABE and MPU subsystem, you have to use L3. For ABE it has memory mapped also to MPU in order to make things faster:
Audio back-end (ABE) 0x4010 0000 0x401F FFFF 1MB ABE domain (direct Cortex-A9 MPU access).Hope this helps
Thanks to Ranjith and Israel.
As per our discussion on this forum, I come to the following conclusion :
1) The coretx A9 having :
L1 I Cache: 32 KB / CPU
L1 D cache:32 KB / CPU
L2 Shared by two cortex : 1MB
2)Available On chip memory (4GB):
- Q0 :1GB >>GPMC
- Q1 : 1GB >> Boot ROM : 48KB , SAR ROM :4KB,SAR RAM : 8KB, L3 OCM_RAM : 56KB etc..
- Q2 :1GB >> SDRAM
- Q3 :1GB >> SDRAM
Please give your comments ..........
What I understand from TRM is that there are L1 memories all over the submodules, some are cache.
Like the 2 inside each Cortex A9 Core that are 32KB each (Instruction and Data) - See: Figure 4-1. Cortex-A9 MPU Subsystem Overview
But the memory you were initially asking is the L3 Memory Space Mapping (Chapter 2.2 in TRM). That memory as far as I understand in not the same that the cache previously mentined, this is the memory that the L3 interconector access in order to communicate the submodules, because submodules doesn't communicate eachother directly. And the designated memory for each submodule is in Table 2-1. Global Memory Space Mapping.
As you can see there is memory assigned for Cortex-A9 MPU, Cortex-M3 MPU and DSP submodules.
Cortex-A9 MPU memory:
* Audio back-end (ABE) 0x4010 0000 0x401F FFFF 1MB ABE domain (direct Cortex-A9 MPU access). See Table 2-6.
Cortex-M3 MPU memory:
* Dual Cortex-M3 0x5500 0000 0x55FF FFFF 16MB Dual Cortex-M3 subsystem target subsystem target
???? - Not available in public TRM probably
This memory is not shared between the 3 modules you asked, for any transaction between those modules the L3 interconector should be involved.
ABE and Cortex-A9 MPU modules share memory, so they can make transactions without involve the L3 interconector.
That is my understanding after read chapter 2 Memory Mapping, 4 Dual Cortex-A9 MPU Subsystem and 7 Dual Cortex-M3 MPU Subsystem. Does it make sense?
I understood this point and I was trying to access LPDDR2 memory location starting from 0X8000 0000 with length of 1GB .
I mentioned this origin and length of LPDDR2 memory in linker cmd file , but i am getting "A data verification error occurred ,file load failed "
Means that LPDDR2 memory i am not able to access .......
How should I access this memory for my use (1GB)........
This question is also posted in http://e2e.ti.com/support/omap/f/849/t/184890.aspx. Will use that thread instead. Closing this one.
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I will go with the new thread .
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