Are there any restriction to enable VFP in 66AK2H CortexA15 cpu1, cpu2, cpu3?

RY9983

Other Parts Discussed in Thread: 66AK2H12, OMAP-L138

Hello,
I am evaluating 66AK2H12/06.
Are there any restriction to enable VFP in CortexA15 cpu1, cpu2, cpu3?

I perform following source code to enable VFPU.
Although CortexA15 cpu0 can return check flag correctly, other CPUs(cpu1, cpu2, cpu3) can not .
( I am not sure if undefined instruction exception is occured, or not, because I have not been able to connect debugger to K2HEVM. )

reset_entry
if (master_core) {
    // Arm boot magic address configuration
     *(unsigned int *)0x0C5AD004   = reset_entry;
    // cpuX domain Next State. Powered ON configuration
     *(unsigned int *)0x01E80414 = 0;
    // Power domain transition command
     *(unsigned int *)0x01E8040C = 1;
｝

// enable to access for CP10 & CP11 (VFP)
mov r0, 0x00F00000
mcr p15, 0, r0, c1, c0, 2
isb
// enable VFP
mov r3, #0x40000000
vmsr fpexc, r3
//Check flag

Reference document:
・spruhj4.pdf
　->KeyStone II Architecture　ARM CorePac　User Guide
(P28) 2.5 VBUSP Memory-Mapped Registers

・ARM ® Cortex ® -A15 MPCore ™ Processor Revision: r4p0 Technical Reference Manual
->14.2.2 Enabling Advanced SIMD and VFP extensions
->Using the Advanced SIMD and VFP in Secure state only

If there are any restrictions, please let me know.
Best regards, RY

over 9 years ago

0 Raja over 9 years ago

TI__Guru* 81335 points

Hi RY,

We are working on your post. We will get back to you. Thank you for your patience.

0 RY9983 over 9 years ago in reply to Raja

Guru 10570 points

Rajasekaran-san,

Thanks for your support !
I checked it today by CCS.
I could see it happened undefined exception on CortexA15.

Best regards, RY

0 RY9983 over 9 years ago in reply to RY9983

Guru 10570 points

Rajasekaran-san,
Thank you so much for your support!

I would like to ask our customer to wait a few days.
How long days will you need to return 1st conclusion?

Best regards, RY

0 Rex Chang over 9 years ago in reply to RY9983

TI__Guru 50170 points

Hi, RY,

The customer may want to get a copy of the ARM TRM which describes more details on how to enable the VFP. My interpretation of the enabling steps may involved setting either SCR or NSACR. These are non-TI specific questions, I suggest customer posts the questions to ARM support which you may get more precise answers.

Rex

0 RY9983 over 9 years ago in reply to Rex Chang

Guru 10570 points

Rex-san,

Thank you so much for your comment.
Although we checked SCR and NSACR, we could not clear.
I will ask them to post question to ARM support.

Best regards, RY

0 RY9983 over 9 years ago in reply to RY9983

Guru 10570 points

Hello Rex-san, Rajasekaran-san,

Although we got ARM support, VFP have never enabled.
If you have any update this, I will appreciate you.

Can I have asking to you?
- 66AK2H can use VFP. Is that right?
- Can you provide us some examples to enable VFP?

Now, I am looking for the reference source code in linux sdk.
Best regards, RY

0 RY9983 over 9 years ago in reply to RY9983

Guru 10570 points

Hello,
I found that CA15 is changed CPU state to Non-secure mode in the Boot ROM.
In non-secure mode, VFP can not be enabled.

I found following code in the Boot ROM.
    00000434 ee110f11 : mrc             p15, 0, r0, c1, c1, 0
    00000438 e3800001 : orr             r0, r0, #1
    0000043c ee010f11 : mcr             p15, 0, r0, c1, c1, 0 // SCR.NS=1 (Non-secure mode)

Can I change CA15 to secure mode?
Can I use VFP in 66AK2H12/06?

Best regards, RY

0 Rex Chang over 9 years ago in reply to RY9983

TI__Guru 50170 points

Hi, RY,

Linux kernel for K2H supports VFP, and is shown in the boot logs

[ 10.661876] VFP support v0.3: implementor 41 architecture 4 part 30 variant f rev 0

Please refer to the code in arch/arm/vfp.

Rex

0 RY9983 over 9 years ago in reply to Rex Chang

Guru 10570 points

Rex-san,
Thank you so much for your reply!
I will check linux code.

There is secure device and Non-secure device in the 66AK2H12/06 datasheet.
Secure ROM boot and Public ROM Boot is existed.
But, ARM Bootloader UG supports only Non-secure boot mode.

My understanding is :
- Secure device is not generic parts.
- 66AK2H12/06 is normally non-secure device and supports only Public ROM boot.

Is my understanding correct?

Best regards, RY

0 Raja over 9 years ago in reply to RY9983

TI__Guru* 81335 points

Hi RY,

Yes. Your understanding is correct.

Thank you.

0 RY9983 over 9 years ago in reply to Raja

Guru 10570 points

Rajasekaran-san,

Thank you for your answer.
So, this is my understanding:
- 66AK2H12/06 is non-secure device.
- It becomes non-secure mode in Boot ROM code.
- It can not be changed to secure mode.
Are there any mistakes?

Best regards, RY

0 Raja over 9 years ago in reply to RY9983

TI__Guru* 81335 points

Hi RY-san,

From my understanding, secure and non-secure are two different parts.

In OMAP-L138 data manual, it is documented in section "7.1.2 Device Nomenclature".

http://processors.wiki.ti.com/index.php/Basic_Secure_Boot_for_OMAP-L138_C6748#How_do_I_know_I_have_received_a_secure_part.3F

But this information is missing in K2H data manual.

I will work with team on this. If any deviation in my understanding, will post back here.

Also, we would recommend you to create a new thread for secure device queries.

Thank you for your patience.

0 RY9983 over 9 years ago in reply to Raja

Guru 10570 points

Rajasekaran-san,

Thank you for your return.
All right. I will post other thread about secure device.

Since I need to enable VFP, can I have once more question?
AM335x supports special secure monitor functions.
Is there identical function in 66AK2H12/06 to enable VFP?

Best regards, RY

0 Rex Chang over 9 years ago in reply to RY9983

TI__Guru 50170 points

Hi, RY,

Please clone boot monitor code as described in Keystone-II User's Guide. Boot Monitor has non-sec and sec part of the code. RBL calls into non-sec code which issues a "smc #0" call to sec part of the code. In the secure code, VFP is enabled in skern_setup_cp15().

Rex

0 RY9983 over 9 years ago in reply to Rex Chang

Guru 10570 points

Rex-san,

Thank you so much for your reply! It was very helpful for us.

But, I could not find the Keystone-II User's Guide which is described boot monitor call.
Which document do you point out? Please let me know the document number spruXXX.

Best regards, RY

0 Rex Chang over 9 years ago in reply to RY9983

TI__Guru 50170 points

Hi, RY,

Please see in http://processors.wiki.ti.com/index.php/MCSDK_UG_Chapter_Exploring#Boot_Monitor_Build_instructions

Rex

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Are there any restriction to enable VFP in 66AK2H CortexA15 cpu1, cpu2, cpu3?