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Benoît Thébaudeaueec3f022013-04-23 10:17:47 +00001U-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
Ye Lid4d1dd62016-02-01 10:41:31 +080010 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.
Fabio Estevam6f3bef92013-12-23 13:07:17 -020014
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
Stefano Babic40f48392015-12-11 17:30:42 +010090
912. Using imx_usb_loader for first install with SPL
92--------------------------------------------------
93
94imx_usb_loader is a very nice tool by BoundaryDevice that
95allow to install U-Boot without a JTAG debugger, using
96the USB boot mode as described in the manual. It is
97a replacement for Freescale's MFGTOOLS.
98
99The sources can be found here:
100
101 https://github.com/boundarydevices/imx_usb_loader.git
102
103Booting in USB mode, the i.MX6 announces itself to the Linux Host as:
104
105Bus 001 Device 111: ID 15a2:0061 Freescale Semiconductor, Inc.
106
107imx_usb_loader is able to download a single file (u-boot.imx)
108to the board. For boards without SPL support, it is enough to
109issue the command:
110
111 sudo ../imx_usb_loader/imx_usb -v u-boot.imx
112
113Getting U-Boot when SPL support is active, it requires
114two downloads. imx_usb_loader downloads the SPL into
115OCRAM and starts it. SPL will check for a valid u-boot.img, and
116because it is not found, it will wait for it using the y-modem
117protocol via the console.
118
119A first install is then possible by combining imx_usb_loader with
120another tool such as kermit.
121
122sudo ../imx_usb_loader/imx_usb -v SPL
123kermit kermit_uboot
124
125and kermit_uboot contains something like this (set line should be adjusted):
126
127set line /dev/ttyUSB1
128set speed 115200
129SET CARRIER-WATCH OFF
130set flow-control none
131set handshake none
132set prefixing all
133set file type bin
134set protocol ymodem
135send u-boot.img
136c
137
138The last "c" command tells kermit (from ckermit package in most distros)
139to switch from command line mode to communication mode, and when the
140script is finished, the U-Boot prompt is shown in the same shell.