| Benoît Thébaudeau | eec3f02 | 2013-04-23 10:17:47 +0000 | [diff] [blame] | 1 | U-Boot for Freescale i.MX6 |
| 2 | |
| 3 | This file contains information for the port of U-Boot to the Freescale i.MX6 |
| 4 | SoC. |
| 5 | |
| 6 | 1. CONVENTIONS FOR FUSE ASSIGNMENTS |
| 7 | ----------------------------------- |
| 8 | |
| 9 | 1.1 MAC Address: It is stored in fuse bank 4, with the 32 lsbs in word 2 and the |
| 10 | 16 msbs in word 3. |
| Fabio Estevam | 6f3bef9 | 2013-12-23 13:07:17 -0200 | [diff] [blame] | 11 | |
| 12 | Example: |
| 13 | |
| 14 | For reading the MAC address fuses on a MX6Q: |
| 15 | |
| 16 | - The MAC address is stored in two fuse addresses (the fuse addresses are |
| 17 | described in the Fusemap Descriptions table from the mx6q Reference Manual): |
| 18 | |
| 19 | 0x620[31:0] - MAC_ADDR[31:0] |
| 20 | 0x630[15:0] - MAC_ADDR[47:32] |
| 21 | |
| 22 | In order to use the fuse API, we need to pass the bank and word values, which |
| 23 | are calculated as below: |
| 24 | |
| 25 | Fuse address for the lower MAC address: 0x620 |
| 26 | Base address for the fuses: 0x400 |
| 27 | |
| 28 | (0x620 - 0x400)/0x10 = 0x22 = 34 decimal |
| 29 | |
| 30 | As the fuses are arranged in banks of 8 words: |
| 31 | |
| 32 | 34 / 8 = 4 and the remainder is 2, so in this case: |
| 33 | |
| 34 | bank = 4 |
| 35 | word = 2 |
| 36 | |
| 37 | And the U-boot command would be: |
| 38 | |
| 39 | => fuse read 4 2 |
| 40 | Reading bank 4: |
| 41 | |
| 42 | Word 0x00000002: 9f027772 |
| 43 | |
| 44 | Doing the same for the upper MAC address: |
| 45 | |
| 46 | Fuse address for the upper MAC address: 0x630 |
| 47 | Base address for the fuses: 0x400 |
| 48 | |
| 49 | (0x630 - 0x400)/0x10 = 0x23 = 35 decimal |
| 50 | |
| 51 | As the fuses are arranged in banks of 8 words: |
| 52 | |
| 53 | 35 / 8 = 4 and the remainder is 3, so in this case: |
| 54 | |
| 55 | bank = 4 |
| 56 | word = 3 |
| 57 | |
| 58 | And the U-boot command would be: |
| 59 | |
| 60 | => fuse read 4 3 |
| 61 | Reading bank 4: |
| 62 | |
| 63 | Word 0x00000003: 00000004 |
| 64 | |
| 65 | ,which matches the ethaddr value: |
| 66 | => echo ${ethaddr} |
| 67 | 00:04:9f:02:77:72 |
| 68 | |
| 69 | Some other useful hints: |
| 70 | |
| 71 | - The 'bank' and 'word' numbers can be easily obtained from the mx6 Reference |
| 72 | Manual. For the mx6quad case, please check the "46.5 OCOTP Memory Map/Register |
| 73 | Definition" from the "i.MX 6Dual/6Quad Applications Processor Reference Manual, |
| 74 | Rev. 1, 04/2013" document. For example, for the MAC fuses we have: |
| 75 | |
| 76 | Address: |
| 77 | 21B_C620 Value of OTP Bank4 Word2 (MAC Address)(OCOTP_MAC0) |
| 78 | |
| 79 | 21B_C630 Value of OTP Bank4 Word3 (MAC Address)(OCOTP_MAC1) |
| 80 | |
| 81 | - The command '=> fuse read 4 2 2' reads the whole MAC addresses at once: |
| 82 | |
| 83 | => fuse read 4 2 2 |
| 84 | Reading bank 4: |
| 85 | |
| 86 | Word 0x00000002: 9f027772 00000004 |