topic Re: fuse prog in i.MX Processors

fuse prog

lifusong — Mon, 03 Aug 2015 02:23:15 GMT

Dear .

the uboot(imx6q-2014.04) Provided a command fuse

like as fuse read 4 2 2 will show MAC

and fuse prog 4 2 0x11223344

the question. I can read mac info through command fuse read 4 2 2.

but can't set through command fuse prog 4 2 0x11223344

anybody can help me.

Re: fuse prog

igorpadykov — Mon, 03 Aug 2015 04:15:54 GMT

Hi li

fuses are one time programmable registers, they can not be reprogrammed to another

values. For fuse blow procedure one can refer to below link

Q&A: How to program i.MX6 eFUSE?

https://community.freescale.com/docs/DOC-95458

Best regards

igor

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Re: fuse prog

lifusong — Mon, 03 Aug 2015 05:05:54 GMT

Dear igorpadykov.

thanks for you replay.

But can't found this command.

=> imxotp

Unknown command 'imxotp' - try 'help'

our board is imx6q ,uboot is 2014.04

Re: fuse prog

BiyongSUN — Mon, 03 Aug 2015 05:42:33 GMT

you can type help to get the command list in the uboot.

U-Boot 2014.04 (Jul 30 2015 - 14:46:24)

=> fuse
fuse - Fuse sub-system

Usage:
fuse read <bank> <word> [<cnt>] - read 1 or 'cnt' fuse words,
    starting at 'word'
fuse sense <bank> <word> [<cnt>] - sense 1 or 'cnt' fuse words,
    starting at 'word'
fuse prog [-y] <bank> <word> <hexval> [<hexval>...] - program 1 or
    several fuse words, starting at 'word' (PERMANENT)
fuse override <bank> <word> <hexval> [<hexval>...] - override 1 or
    several fuse words, starting at 'word'
=>

Re: fuse prog

lifusong — Mon, 03 Aug 2015 07:10:19 GMT

Dear sir.

I Know fuse command .

But my question is I can't modify mac through fuse prog 4 2 0x11223344

igorpadykov said only can program one time.but if fill error mac ,and how to fix it?

Re: fuse prog

igorpadykov — Mon, 03 Aug 2015 07:28:28 GMT

could you clarify what do you mean by

"I can't modify mac through fuse prog" ?

Re: fuse prog

lifusong — Mon, 03 Aug 2015 07:53:29 GMT

Dear sir.

I want re-set mac address.

uboot provided fuse read and fuse prog command.

but command fuse prog 4 2 0x11223344 can't re-set mac address,

and you give me a link Q&A: How to program i.MX6 eFUSE?

there don't have command imxotp.

below is the uboot command message.

=> imxotp

Unknown command 'imxotp' - try 'help'

Re: fuse prog

lifusong — Mon, 03 Aug 2015 08:42:29 GMT

Dear igorpadkov.

you said fuses are one time programmable registers, they can not be reprogrammed to another

but this link Re: MAC fuses lock can re-set the mac .

can you tell me the reason?

by the way,my board is imx6q.

thanks.

Re: fuse prog

lifusong — Mon, 03 Aug 2015 09:04:44 GMT

i had check OCOTP_LOCK[9:8] == 00b means writing shadow and OTP fuse is enabled.

i try to modify this register with command fuse prog 0 0 20220302 ,don't have any effect.

fuse read 0 0 get the value is 0x20220002

Re: fuse prog

BiyongSUN — Mon, 03 Aug 2015 09:11:10 GMT

fusong,

Some fuse may burned already. the fuse is OTP cannot burn again.

Re: fuse prog

lifusong — Mon, 03 Aug 2015 09:20:53 GMT

Dear BiyongSUN .

thanks for your help. if i write error value into OCOTP_MAC0 and OCOTP_MAC1 how to modify to right value.

and I try to fuse prog 4 2 0x11eeddff on other board.and still can't wirte value to OCOCP_MAC0.

the other board OCOTP_MAC0 OCOTP_MAC1 is zero.

Re: fuse prog

igorpadykov — Mon, 03 Aug 2015 11:35:53 GMT

please check

OTP - Wikipedia, the free encyclopedia

so if all fuses are zero, they can not be recovered to "1".

Re: fuse prog

BiyongSUN — Tue, 04 Aug 2015 05:15:41 GMT

you can try it in the linux using echo command.

/sys/fsl_otp

Use echo command to burn the fuse.

Ex:
echo 0x00006200 > /sys/fsl_otp/HW_OCOTP_GP1

Still need to reminder you the fuse is OTP.

Re: fuse prog

lifusong — Tue, 04 Aug 2015 10:07:44 GMT

is the /sys/fsl_otp/HW_OCOTP_xxxx driver ok?

the HW_OCOTP_LOCK = 0x20220302 (I don't know reason this value chang to 0x20220302 form 0x20220002, I only at uboot command try fuse prog command).

I try to run "echo 0x20220002 > /sys/fsl_otp/HW_OCOTP_LOCK" many times.

and the HW_OCOTP_LOCK still is 0x20220302.

so i try to run "echo 1 > /sys/fsl_otp/HW_OCOTP_LOCK" and found this value had been changed to eaba7f02

what is the reason? how can fill right value to HW_OCOTP_XXXX.

Re: fuse prog

lifusong — Tue, 04 Aug 2015 10:12:59 GMT

and before run fuse prog 4 2 xxxx.

the HW_OCOTP_MAC0 and MAC1 is zero.

I try to change this value and use command "echo 0x11223344 >/sys/fsl_otp/HW_OCOTP_MAC0",and can't change this value.

but echo 1 > /sys/fsl_otp/HW_OCOTP_MAC0 will change this value to 0xd3ee7bf5.I don't know the reson ,why this value will change to 0xd3ee7bf5,command means write one to HW_OCOTP_MAC0.

Re: fuse prog

lifusong — Tue, 04 Aug 2015 10:18:18 GMT

please see below info.

root@sabresd_6dq:/ # cat /sys/fsl_otp/HW_OCOTP_MAC0

0xd3ee7bf5