SYS/BIOS Arm A15 Support

Hi Tugrul,

Some of the peripheral base addresses on Keystone II are different from those on DRA7X/OMAP5430. For instance the GIC (Interrupt Controller) base addresses are different. By default, the Hwi module (Interrupt Controller Driver) gets added to every application and its startup code will generate an exception unless the base addresses are correct.

You can add the following lines to your *.cfg script to fix the GIC Distributor and Controller Base addresses:

var Hwi = xdc.useModule('ti.sysbios.family.arm.gic.Hwi');
Hwi.gicdBaseAddress = 0x0256xxxx; // Please check your TRM to determine the exact base addresses
Hwi.giccBaseAddress = 0x0256xxxx;

If you have the MMU enabled (It is enabled by default), then you will also need to add entries for 0x0256xxxx to mark this region as Device Memory/Strongly Ordered. This is required to prevent a MMU fault.

Link to MMU module cdoc which has some examples showing how to add MMU entries:

http://software-dl.ti.com/dsps/dsps_public_sw/sdo_sb/targetcontent/bios/sysbios/6_35_03_47/exports/bios_6_35_03_47/docs/cdoc/index.html#ti/sysbios/family/arm/a15/Mmu.html

The default timer module used by DRA7X and OMAP5430 uses the A15 Generic Timers. This timer module uses CP15 instructions to program the timer so there are no base addresses to deal with here. You do need to set the right timer frequency though. The Timer.intFreq config param in specific needs to be set: http://software-dl.ti.com/dsps/dsps_public_sw/sdo_sb/targetcontent/bios/sysbios/6_35_03_47/exports/bios_6_35_03_47/docs/cdoc/index.html#ti/sysbios/family/arm/systimer/Timer.html#int.Freq

On DRA7X and OMAP5430 the A15 Generic Timers have an effective frequency of 6.144 MHz. I believe on Keystone II the frequency is different. You need to worry about this only if you plan to use timers or leverage the SYS/BIOS clock which internally uses these timers. Also, please note that SYS/BIOS only supports non-secure mode so if the A15 is in secure mode, you need to change the security mode to non-secure first. This can be done using the gel script in CCS or in the bootloader.

If you build the application with the above changes, I would expect it to run fine.

As for the errors that you get at load time. Can you open Tools->ARM Advanced features and check if the MMU is enabled when you load your app ? You want to disable the MMU, Data and Instruction cache before loading your app.

Best,

Ashish

Hi Ashish;

Thank you for your detailed answer. After I post the message, I tried to init the board by using a .gel file before loading the out file. It seems i solved the connection problem. ( when try to load ARM tries to access DDR, and also pll is not initialized )

I am not familiar with ARM processors but I tried to debug it. When I loaded it, Program Counter could not come to main. When I deasassembly it, and proceed through _c_int, I noticed it stuck somewhere related with xds functions. 

Now, I will try your suggestions then  I will inform you. Thanks

Tugrul

Hi Tugrul,

tugrul mutlu said:

After I post the message, I tried to init the board by using a .gel file before loading the out file. It seems i solved the connection problem. ( when try to load ARM tries to access DDR, and also pll is not initialized )

Looks like the memory controller (EMIF) is not initialized. One way is to run some gel script to do all the required board init. But, I am not sure where to get the right gel scripts for Keystone II. You may want to check on the Keystone forum. An alternative is to run uboot and let it do the board init. Here's a wiki page that explains how to run uboot from CCS:

http://processors.wiki.ti.com/index.php/MCSDK_UG_Chapter_Tools#Loading_and_Running_U-Boot_using_CCS

Best,

Ashish

Hi Ashish;

I update .cfg file as you suggested. I attached it. I added the lines below. 

var Hwi = xdc.useModule('ti.sysbios.family.arm.gic.Hwi');
Hwi.gicdBaseAddress = 0x02561000;
Hwi.giccBaseAddress = 0x02564000;

Actually I am not sure about these values.Here I paste the pictures where i got these values. 

These picture is from Cortex A-15 TRM. I got 0x1000 for distributor & 0x4000 for controller.( ?)

These one is from KeyStone II memory Map. This line is the only related one with GIC. There is no Distributor or Controller Base Addres.

I also check A-15 Generic Timers frequency for Keystone II but I couldnt found any information about it.. 

After I connect the ARM with the emulator, I check the MMU. It seems it is disabled. 

With these configuration, I load the out file. When I run it, an exeption occured. I copy&paste it here. 

Exception occurred in ThreadType_Main.
Main handle: 0x0.
Main stack base: 0x900122e8.
Main stack size: 0x1000.
R0 = 0x40000000 R8 = 0x00008030
R1 = 0x00000001 R9 = 0xffffffff
R2 = 0x00000006 R10 = 0x00000000
R3 = 0x00000004 R11 = 0x00000002
R4 = 0x0000000f R12 = 0x000001df
R5 = 0x0000001c SP(R13) = 0xfffff910
R6 = 0x00000001 LR(R14) = 0x9000ad70
R7 = 0xffffffff PC(R15) = 0x90000a90
PSR = 0x600001df
ti.sysbios.family.arm.exc.Exception: line 180: E_undefinedInstruction: pc = 0x90000a90, lr = 0x9000ad70.
xdc.runtime.Error.raise: terminating execution

This error occured in _c_int functions. I deassembly it and found where the error is. I copy&paste it here.

#if (defined(__VFP_FP__) && !defined(__SOFTFP__))

@ enable access to cp10 and cp11
@ required for SIMD and VFP to work

movw r0, #0x0000
movt r0, #0x00F0
mcr p15, #0, r0, c1, c0, #2
isb

@ set the FPEXC.EN bit to enable Advanced SIMD and VFP
movw r0, #0x0000
movt r0, #0x4000
fmxr fpexc, r0 @ gcc does not support UAL equivalent
@ instruction, vmsr
#endif

These code is from boot.asm. The error occurs when the PC comes to the red line. I think this instruction is something about floating point operations . I am not sure about it. 

I attached my .cfg file here. Thank you for your help..

3404.sysbios.cfg 

Regards

Tugrul