about memory map setting on davinci platfrom

X. Zhou Mon, 06 Nov 2006 05:22:50 -0800

Title: Message

Hi all, I have serveral questions about memory map setting on davinci platfrom.

(1).

i want to locate the stacks of DSP algorithms running on DAVINCI DSP to a specific memory segment. How should i do?

as you know, I use the DVSDK examples software shipped with DVEVM6446 board as my development template.

I found that in $(EXAMPLE_ROOTDIR)/servers/video_copy/video_copy.cfg file, there is some stack-related configurations:

Server.threadAttrs.stackSize = 2048;
Server.threadAttrs.priority = Server.MINPRI;

Server.algs =

[
    {name: "viddec_copy", mod: VIDDEC_COPY, threadAttrs: {
        stackSize: 4096, stackMemId: 0, priority: Server.MINPRI + 1}
    },
    {name: "videnc_copy", mod: VIDENC_COPY, threadAttrs: {
        stackSize: 4096, stackMemId: 0, priority: Server.MINPRI + 1}
    },
];

In my opinion, stackMemId should be the memory segmenet ID for each DSP algorithm. But how could i know which ID is correspondin to my target memory segment? For example, i have 3 memory segments in my *.tcf file:

var mem_ext = [
{
    comment:    "L1DSRAM: L1 SRAM for dynamic algmem allocation and task stack",
    name:       "L1DSRAM",
    base:       0x11F04000,
    len:        0x10000,      // 64k
    space:      "data"
},
{
    comment:    "IRAM: L2 SRAM for dynamic algmem allocation",
    name:       "IRAM",
    base:       0x11800000,
    len:        0x8000,       // 32k
    space:      "data"
},
{
    comment:    "DDR: off-chip memory for application code and data",
    name:       "DDR",
    base:       0x8F000000,   // 240MB
    len:        0xE00000,     // 14 MB

space: "code/data"
},

...

}

i want to map stack of a DSP algorithm to L1DSRAM, then, which segment id does L1SDRAM correspond to?

(2).

another question, besides the setting in the above file, there are some stack-related configuration in $(EXAMPLE_ROOTDIR)/servers/video_copy/video_copy.tcf file as well:

/* ===========================================================================
* MEM : startup and SWI stack size
* ===========================================================================
*/
prog.module("MEM").STACKSIZE = 0x1000;

/* ===========================================================================
* TSK : Global
* ===========================================================================
*/
prog.module("TSK").STACKSEG = bios.DDR;

I want to know the difference between the stack in *.tcf file and the stack in *.cfg file.

Does they point to the same stack?

maybe, i need more detail information about all possible stack types in DSP/BIOS. as far, i know there are 4 types of stacks in DSP/BIOS:

system stack ( == global stack???); task stacks(each task have its indepedent stack); SWI stack; HWI stack;

but i am not very clear about the system stack. Anyone can give me a more detailed explanation?

(3)

in $(EXAMPLE_ROOTDIR)/servers/video_copy/video_copy.tcf file,

             bios.setMemDataNoHeapSections (prog, bios.DDR);
            bios.setMemDataHeapSections (prog, bios.DDRALGHEAP_CACHEABLE);
        prog.module("MEM").MALLOCSEG = bios.DDR;

what is the MemDataNoHeapSections??? what is the MemDataHeapSections?? what is the difference between of MemDataHeapSections and ".sysmem" section?

and does the "prog.module("MEM").MALLOCSEG = bios.DDR" setting mean that, if i use malloc() ( not MEM_alloc() ) function to allocate memory, DSP/BIOS will map the ".sysmem" section to "bios.DDR" segment, i.e., DSP/BIOS will get memory from the heap located in "bios.DDR" segment?

Any opinion is appreriated!

BR,

ZhouXiao

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