OMAPL138 Syslink printing from shared memory not showing data

Usman Majid

I'm using Syslink 2_21_03_11 example 4 SharedRegion as my starting point.

The example passes a string from the ARM to the DSP and capitalizes it on the DSP side and notifies the ARM that the operation was complete.

I replaced that string with an array of structs which contain additional arrays, all static, and I am sending a pointer address to that struct object from the ARM to the DSP.

Out of the 20 values being stored inside the struct and being written/read on both sides, one array seems to have a problem of not displaying its first block.

Lets say I have this array a[4] which is inside a struct s[32].

s[0].a[1 to 4] is showing up as all 0's on the ARM side, but the values are hidden they are not actually 0, because the transpose of that same array is taken and the output is on s[0].b and the output is correct. Additionally the rest of s[1-31].a[1-4] is showing up correctly, just the first s[0].a[1-4] is not.

Also, if I run the ARM side of the program again, right after the previous run, it will print out all values correctly.

There is some bizarre problem going on and its not very important for me to see those values as I only care about the values being correct themselves. But I'm wondering if anyone has encountered a problem like this and have any clues to what it might be.

over 9 years ago

0 Titusrathinaraj Stalin over 9 years ago

TI__Guru** 116100 points

We are working with factory team on the above question.

0 Rahul Prabhu over 9 years ago

TI__Guru** 116830 points

Usman,

This appears to be a cache coherency issue. Please refer to the section of for cache coherency in this article. The wiki refers to codec engine software but that concept applies to syslink as well.

processors.wiki.ti.com/.../Codec_Engine_Application_Developers_Guide

Can you try Cache invalidating the smaller structure on the ARM before reading it on the ARM to see if correct contents are being read.

Regards,
Rahul

0 Usman Majid over 9 years ago in reply to Rahul Prabhu

Intellectual 620 points

I am running

Cache_inv((uint32_t *)0x80000000, 0x00020000, 0x2 ,1);

and it is still producing the same output

My memory map looks like this

var SR_0 = {
        name: "SR_0", space: "data", access: "RWX",
        base: 0xC2000000, len: 0x10000,
        comment: "SR#0 Memory (64 KB)"
    };

var SR_1 = {
        name: "SR_1", space: "data", access: "RWX",
        base: 0xC2010000, len: 0xFF0000,
        comment: "SR#1 Memory (15 MB)"
    };

Build.platformTable["ti.platforms.evmOMAPL138:dsp"] = {
    externalMemoryMap: [
        [ SR_0.name, SR_0 ],
        [ SR_1.name, SR_1 ],
        [ "DSP_PROG", {
            name: "DSP_PROG", space: "code/data", access: "RWX",
            base: 0xC3000000, len: 0x800000,
            comment: "DSP Program Memory (8 MB)"
        }]
    ],
    codeMemory:  "DSP_PROG",
    dataMemory:  "DSP_PROG",
    stackMemory: "DSP_PROG",
    l1DMode: "32k",
    l1PMode: "32k",
    l2Mode: "32k"
};

0 Usman Majid over 9 years ago in reply to Usman Majid

Intellectual 620 points

Edit: I was using the wrong values, I changed it to
Cache_inv((uint32_t *)0x11808000, 0x00007FFF, 0x2 ,1);
and it shows up correctly on the first run now.

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OMAPL138 Syslink printing from shared memory not showing data