topic Re: What is the difference between open device and close device? in i.MX Processors

What is the difference between open device and close device?

t-iishii — Mon, 17 Apr 2017 11:28:13 GMT

Hello

In i.MX6Quad,

What is the difference between open device and close device?

Our customer, hope to know which functions will have difference of each module functions before SEC_CONFIG[1]=0(open device) and after SEC_CONFIG[1]= 1(closed device).

Are there any modules that affect other than the modules in Figure 11-1. Security subsystem (simplified)

of Reference Manual (IMX6DQRM)?

Best regards,

Ishii.

Re: What is the difference between open device and close device?

Carlos_Musich — Wed, 19 Apr 2017 22:31:36 GMT

Hi Takayuki,

SEC_CONFIG is a fuse. Its value determine whether security is enabled or not.

0 - Open - allows any code to be flashed and executed, even if it has no validsignature.

1 - Closed (Security On)

Best regards,
TIC

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Re: What is the difference between open device and close device?

t-iishii — Wed, 26 Apr 2017 08:09:46 GMT

Hello Musich

Thank you for your response.

To closed( Security On) the device, does it need not only SEC_CONFIG but also DIR_BT_DIS bit to blown?

Because in Reference Manual (IMX6DQRM.pdf) page 377,

NOTE
If the DIR_BT_DIS eFuse is not blown, authentication may be
bypassed. In this case the system is not secure.
Chapter 8 System Boot

But every documents to operate setting sec_config and hashkey,

It will set only SET_CONFIG[1] bit to SRC_SBMR2 register like this

$ cd /sys/fsl_opt

$ echo 2 > HW_OCOPT_CFG5

To keep secure, do we must need to operate?

We must blown the DIR_BT_DIS bit?

Best regards,

Ishii.