which boot device

DavidVescovi

I was trying to determine which device in the in the boot device sequence actually did the boot.

I know I can look at the sysboot field of the control_status register to determine which boot order scheme is used and then I was thinking of looking at the scheme in reverse order to see if the device has its clock enabled (or its pads configured) that would be the device that actually succeeded.

Is this correct? Is there an easier way?

Also, in the firmware after an attempt to boot from a device fails and it moves on to the next one is the previous device's clock turned off? Is its pin mux reset?

over 12 years ago

0 Miroslav Kiradzhiyski XID over 12 years ago

TI__Mastermind 25235 points

Hi,

Please check this thread: http://e2e.ti.com/support/arm/sitara_arm/f/791/p/276254/981707.aspx#981707

frxb is storing the boot device in the SPL to one of the RTC's scratch registers and then reading it back in U-Boot.

Best regards,
Miroslav

0 DavidVescovi over 12 years ago in reply to Miroslav Kiradzhiyski XID

Genius 5470 points

This does not exactly answer my question. Is the boot firmware on chip storing this info to the RTC scratch or is the SPL?

If the SPL is doing it I need to know how the SPL determined which device. I am not using uboot or Linux.

0 Miroslav Kiradzhiyski XID over 12 years ago in reply to DavidVescovi

TI__Mastermind 25235 points

This is from section 26.1.10.2 Execution from the TRM:

The image is executed at the time the ROM Code performs the branch to the first executable instruction inside the Initial SW. For a GP Device in non-XIP, the execution address is the first word after the GP header. The branch is performed in public ARM supervisor mode. The R0 register points to the Booting Parameters structure which contains various information about the booting execution. Table 26-40 details this structure.

The SPL reads the "Current Booting Device" field from this "Booting Parameters Structure" and stores it in a variable, which is later used to determine where to load the U-Boot from.

Please read the appropriate sections of the TRM.

Best regards,
Miroslav

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which boot device