Syntax to allocate memory assignments to faster memory

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Syntax to allocate memory assignments to faster memory

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terrybiberdorf
Contributor II

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

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1 Solution
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Jorge_Gonzalez
NXP Employee
NXP Employee

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 Smiley Happy

/Jorge Gonzalez

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4 Replies
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Hui_Ma
NXP TechSupport
NXP TechSupport

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.

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terrybiberdorf
Contributor II

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?

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324 Views
Jorge_Gonzalez
NXP Employee
NXP Employee

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 Smiley Happy

/Jorge Gonzalez

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Hui_Ma
NXP TechSupport
NXP TechSupport

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

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