topic Syntax to allocate memory assignments to faster memory in Kinetis Microcontrollers

Syntax to allocate memory assignments to faster memory

terrybiberdorf — Thu, 21 Nov 2013 23:05:15 GMT

I've read through the MCU_Kinetis_Compiler.pdf document and other links on the web and having problems with the syntax needed with the Kinetis GCC compiler to re-direct RAM allocaiton to different sections specified by the linker file.

How this came about:

I now have the TWR-MEM board operating, but the mmem is slow. I want my emac buffers and ADC buffers to use the internal SRAM, but all other memory to use the slower mmem.

Now I have my linker file modified to specify all memory to use the mmem. This was easy to do with the linker file modified as follows:

MEMORY {

m_interrupts (RX) : ORIGIN = 0x00000000, LENGTH = 0x000001E0

m_text (RX) : ORIGIN = 0x00000410, LENGTH = 0x0007FBF0

m_data (RW) : ORIGIN = 0x60000000, LENGTH = 0x00080000

m_data_00000000 (RW) : ORIGIN = 0x1FFF0000, LENGTH = 0x0001E000

m_data_20000000 (RW) : ORIGIN = 0x2000E000, LENGTH = 0x00002000

m_cfmprotrom (RX) : ORIGIN = 0x00000400, LENGTH = 0x00000010

}

But my confusion now is the #pragma syntax needed in my source code to direct various buffers to use sections: m_data_00000000 and m_data_20000000.

Now I happen to have my network buffers declared as follows:

NET_BUFQ in_bufq[] =

{

{ 16, 128 },

{ 33, 512 },

};

I thought it would be as simple as adding the following:

#pragma DATA_SECTION(in_bufq,"m_data_20000000")

But I get the following compiler warning, and my allocation is not where I expect it.

D:/Freescale/CW MCU v10.4/MCU/ARM_GCC_Support/ewl/EWL_C/include/ctime:45:0: warning: ignoring #pragma options align [-Wunknown-pragmas]

D:/Freescale/CW MCU v10.4/MCU/ARM_GCC_Support/ewl/EWL_C/include/ctime:307:0: warning: ignoring #pragma options align [-Wunknown-pragmas]

../Sources/userdata.c:229:0: warning: ignoring #pragma DATA_SECTION [-Wunknown-pragmas]

Any suggestions on what the correct syntax should be to instruct the tool chain to allocate my buffers to the memory location I want them located in?

Thanks

Re: Syntax to allocate memory assignments to faster memory

Hui_Ma — Fri, 22 Nov 2013 02:40:03 GMT

Hi Terry,

I am checking with this issue. I will let you know when I could get any updated info.

Thank you for the patience.

B.R.

Ma Hui

Re: Syntax to allocate memory assignments to faster memory

Hui_Ma — Fri, 22 Nov 2013 03:43:10 GMT

Customer can refer below info about define variable in dedicated memory range:

LCF file:

MEMORY {

display (RW) : ORIGIN = 0x60100000, LENGTH = 0x00020000

}

SECTIONS {

___display_ROMStart = ___display_ram_ROMStart + SIZEOF(.display_ram);

.display : AT(___display_ROMStart)

{

. = ALIGN(4);

___display_RAMStart = .;

*(.display) /* This is an User defined section */

___display_RAMEnd = .;

. = ALIGN(4);

} > display

___display_ROMSize = ___display_RAMEnd - ___display_RAMStart;

C file:

#pragma define_section my_ram2 ".display" abs32 RW

__declspec(section "my_ram2") GuiConst_INT8U Display[511];

Wish it helps.

Re: Syntax to allocate memory assignments to faster memory

terrybiberdorf — Fri, 22 Nov 2013 17:11:57 GMT

Hi Ma

Your description helps but I'm still having problems connecting my C code to the linker script.

In my case my linker script is as follows. I would like to place my high speed buffer into memory location = m_data_20000000.

MEMORY {

m_interrupts (RX) : ORIGIN = 0x00000000, LENGTH = 0x000001E0

m_text (RX) : ORIGIN = 0x00000410, LENGTH = 0x0007FBF0

m_data (RW) : ORIGIN = 0x60000000, LENGTH = 0x00080000

m_data_00000000 (RW) : ORIGIN = 0x1FFF0000, LENGTH = 0x00010000

m_data_20000000 (RW) : ORIGIN = 0x20000000, LENGTH = 0x00010000

m_cfmprotrom (RX) : ORIGIN = 0x00000400, LENGTH = 0x00000010

}

In the C code I have the following questions:

#pragma define_section high_speed_buffer_storage ".m_data_20000000" abs32 RW

//question: can you tell me what the named section abs32 represents? Does it matter what I place here?

__declspec(section "high_speed_buffer_storage ") GuiConst_INT8U Display[511];

// question: I've search my code and I cannot find any reference to GuiConst_INT8U.

// This look like its a variable type definition. Where is this defined?

What syntax is needed for my case of __declspec line to assign mybuffer to the memory section high_speed_buffer_storage?

My variable type is: in_bufq

My buffer is as follows:

typedef struct

{

int32_t bufNumber;

int32_t bufSize;

}NET_BUFQ;

#pragma define_section high_speed_buffer_storage ".m_data_20000000" abs32 RW

__declspec(section "high_speed_buffer_storage") NET_BUFQ in_bufq[3];

NET_BUFQ in_bufq[] =

{

{ 16, 128 },

{ 33, 512 },

};

The compiler output is as follows:

D:/Freescale/CW MCU v10.4/MCU/ARM_GCC_Support/ewl/EWL_C/include/ctime:45:0: warning: ignoring #pragma options align [-Wunknown-pragmas]

D:/Freescale/CW MCU v10.4/MCU/ARM_GCC_Support/ewl/EWL_C/include/ctime:307:0: warning: ignoring #pragma options align [-Wunknown-pragmas]

../Sources/userdata.c:230:0: warning: ignoring #pragma define_section high_speed_buffer_storage [-Wunknown-pragmas]

../Sources/userdata.c:231:20: error: expected ')' before string constant

mingw32-make: *** [Sources/userdata.o] Error 1

What am I doing wrong?

Re: Re: Syntax to allocate memory assignments to faster memory

Jorge_Gonzalez — Mon, 02 Nov 2020 13:07:35 GMT

Hello Terry:

In your linker file you should have something like the next:

  ___m_data_20000000_ROMStart = ___ROM_AT + SIZEOF(.data);
  .m_data_20000000 : AT(___m_data_20000000_ROMStart)
  {
     . = ALIGN(4);
     ___m_data_20000000_RAMStart = .;
     *(.m_data_20000000) /* This is an User defined section */
     ___m_data_20000000_RAMEnd = .;
     . = ALIGN(4);
  } > m_data_20000000
  ___m_data_20000000_ROMSize = ___m_data_20000000_RAMEnd - ___m_data_20000000_RAMStart;

If that is the case, you can locate your data structure with the next code:

typedef struct
{
     unsigned int bufNumber;
     unsigned int bufSize;
}NET_BUFQ;


__attribute__ ((section(".m_data_20000000"))) NET_BUFQ in_bufq[] =
{
  { 16, 128 },
  { 33, 512 },
};

Just a few comments to clarify:

- GuiConst_INT8U is a variable from a custom example, so you won't find it in your code.

- __declspec directive works for Freescale Compiler, but in this case you are using GCC compiler, and you need to use __attribute__ instead.

:smileyalert: You read MCU_Kinetis_Compiler.pdf from CodeWarrior 10.4, which includes information about both Freescale and GCC compilers. In CodeWarrior 10.5 there are separate documents: MCU_Kinetis_Compiler.pdf and MCU_Kinetis_GCC.pdf.

When working with GCC tools, you can refer to the next files for more details:

- C:\Freescale\CW MCU v10.4\Cross_Tools\arm-none-eabi-gcc-4_7_3\share\doc\gcc-arm-none-eabi\pdf\ld.pdf

- C:\Freescale\CW MCU v10.4\Cross_Tools\arm-none-eabi-gcc-4_7_3\share\doc\gcc-arm-none-eabi\pdf\gcc\gcc.pdf

Hope you find this useful

/Jorge Gonzalez