1U-Boot for Freescale i.MX6 2 3This file contains information for the port of U-Boot to the Freescale i.MX6 4SoC. 5 61. CONVENTIONS FOR FUSE ASSIGNMENTS 7----------------------------------- 8 91.1 MAC Address: It is stored in fuse bank 4, with the 32 lsbs in word 2 and the 10 16 msbs in word 3[15:0]. 11 For i.MX6SX and i.MX6UL, they have two MAC addresses. The second MAC address 12 is stored in fuse bank 4, with the 16 lsb in word 3[31:16] and the 32 msbs in 13 word 4. 14 15Example: 16 17For reading the MAC address fuses on a MX6Q: 18 19- The MAC address is stored in two fuse addresses (the fuse addresses are 20described in the Fusemap Descriptions table from the mx6q Reference Manual): 21 220x620[31:0] - MAC_ADDR[31:0] 230x630[15:0] - MAC_ADDR[47:32] 24 25In order to use the fuse API, we need to pass the bank and word values, which 26are calculated as below: 27 28Fuse address for the lower MAC address: 0x620 29Base address for the fuses: 0x400 30 31(0x620 - 0x400)/0x10 = 0x22 = 34 decimal 32 33As the fuses are arranged in banks of 8 words: 34 3534 / 8 = 4 and the remainder is 2, so in this case: 36 37bank = 4 38word = 2 39 40And the U-Boot command would be: 41 42=> fuse read 4 2 43Reading bank 4: 44 45Word 0x00000002: 9f027772 46 47Doing the same for the upper MAC address: 48 49Fuse address for the upper MAC address: 0x630 50Base address for the fuses: 0x400 51 52(0x630 - 0x400)/0x10 = 0x23 = 35 decimal 53 54As the fuses are arranged in banks of 8 words: 55 5635 / 8 = 4 and the remainder is 3, so in this case: 57 58bank = 4 59word = 3 60 61And the U-Boot command would be: 62 63=> fuse read 4 3 64Reading bank 4: 65 66Word 0x00000003: 00000004 67 68,which matches the ethaddr value: 69=> echo ${ethaddr} 7000:04:9f:02:77:72 71 72Some other useful hints: 73 74- The 'bank' and 'word' numbers can be easily obtained from the mx6 Reference 75Manual. For the mx6quad case, please check the "46.5 OCOTP Memory Map/Register 76Definition" from the "i.MX 6Dual/6Quad Applications Processor Reference Manual, 77Rev. 1, 04/2013" document. For example, for the MAC fuses we have: 78 79Address: 8021B_C620 Value of OTP Bank4 Word2 (MAC Address)(OCOTP_MAC0) 81 8221B_C630 Value of OTP Bank4 Word3 (MAC Address)(OCOTP_MAC1) 83 84- The command '=> fuse read 4 2 2' reads the whole MAC addresses at once: 85 86=> fuse read 4 2 2 87Reading bank 4: 88 89Word 0x00000002: 9f027772 00000004 90 91