mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-11-14 00:47:26 +00:00
6f3bef9e30
When using the fuse API in U-boot user must calculate the 'bank' and 'word' values. Provide a real example on how to calculate such values for the mx6q. Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com> Reviewed-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
86 lines
2 KiB
Text
86 lines
2 KiB
Text
U-Boot for Freescale i.MX6
|
|
|
|
This file contains information for the port of U-Boot to the Freescale i.MX6
|
|
SoC.
|
|
|
|
1. CONVENTIONS FOR FUSE ASSIGNMENTS
|
|
-----------------------------------
|
|
|
|
1.1 MAC Address: It is stored in fuse bank 4, with the 32 lsbs in word 2 and the
|
|
16 msbs in word 3.
|
|
|
|
Example:
|
|
|
|
For reading the MAC address fuses on a MX6Q:
|
|
|
|
- The MAC address is stored in two fuse addresses (the fuse addresses are
|
|
described in the Fusemap Descriptions table from the mx6q Reference Manual):
|
|
|
|
0x620[31:0] - MAC_ADDR[31:0]
|
|
0x630[15:0] - MAC_ADDR[47:32]
|
|
|
|
In order to use the fuse API, we need to pass the bank and word values, which
|
|
are calculated as below:
|
|
|
|
Fuse address for the lower MAC address: 0x620
|
|
Base address for the fuses: 0x400
|
|
|
|
(0x620 - 0x400)/0x10 = 0x22 = 34 decimal
|
|
|
|
As the fuses are arranged in banks of 8 words:
|
|
|
|
34 / 8 = 4 and the remainder is 2, so in this case:
|
|
|
|
bank = 4
|
|
word = 2
|
|
|
|
And the U-boot command would be:
|
|
|
|
=> fuse read 4 2
|
|
Reading bank 4:
|
|
|
|
Word 0x00000002: 9f027772
|
|
|
|
Doing the same for the upper MAC address:
|
|
|
|
Fuse address for the upper MAC address: 0x630
|
|
Base address for the fuses: 0x400
|
|
|
|
(0x630 - 0x400)/0x10 = 0x23 = 35 decimal
|
|
|
|
As the fuses are arranged in banks of 8 words:
|
|
|
|
35 / 8 = 4 and the remainder is 3, so in this case:
|
|
|
|
bank = 4
|
|
word = 3
|
|
|
|
And the U-boot command would be:
|
|
|
|
=> fuse read 4 3
|
|
Reading bank 4:
|
|
|
|
Word 0x00000003: 00000004
|
|
|
|
,which matches the ethaddr value:
|
|
=> echo ${ethaddr}
|
|
00:04:9f:02:77:72
|
|
|
|
Some other useful hints:
|
|
|
|
- The 'bank' and 'word' numbers can be easily obtained from the mx6 Reference
|
|
Manual. For the mx6quad case, please check the "46.5 OCOTP Memory Map/Register
|
|
Definition" from the "i.MX 6Dual/6Quad Applications Processor Reference Manual,
|
|
Rev. 1, 04/2013" document. For example, for the MAC fuses we have:
|
|
|
|
Address:
|
|
21B_C620 Value of OTP Bank4 Word2 (MAC Address)(OCOTP_MAC0)
|
|
|
|
21B_C630 Value of OTP Bank4 Word3 (MAC Address)(OCOTP_MAC1)
|
|
|
|
- The command '=> fuse read 4 2 2' reads the whole MAC addresses at once:
|
|
|
|
=> fuse read 4 2 2
|
|
Reading bank 4:
|
|
|
|
Word 0x00000002: 9f027772 00000004
|