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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
10 16 msbs in word 3.
Fabio Estevam6f3bef92013-12-23 13:07:17 -020011
12Example:
13
14For reading the MAC address fuses on a MX6Q:
15
16- The MAC address is stored in two fuse addresses (the fuse addresses are
17described in the Fusemap Descriptions table from the mx6q Reference Manual):
18
190x620[31:0] - MAC_ADDR[31:0]
200x630[15:0] - MAC_ADDR[47:32]
21
22In order to use the fuse API, we need to pass the bank and word values, which
23are calculated as below:
24
25Fuse address for the lower MAC address: 0x620
26Base address for the fuses: 0x400
27
28(0x620 - 0x400)/0x10 = 0x22 = 34 decimal
29
30As the fuses are arranged in banks of 8 words:
31
3234 / 8 = 4 and the remainder is 2, so in this case:
33
34bank = 4
35word = 2
36
37And the U-boot command would be:
38
39=> fuse read 4 2
40Reading bank 4:
41
42Word 0x00000002: 9f027772
43
44Doing the same for the upper MAC address:
45
46Fuse address for the upper MAC address: 0x630
47Base address for the fuses: 0x400
48
49(0x630 - 0x400)/0x10 = 0x23 = 35 decimal
50
51As the fuses are arranged in banks of 8 words:
52
5335 / 8 = 4 and the remainder is 3, so in this case:
54
55bank = 4
56word = 3
57
58And the U-boot command would be:
59
60=> fuse read 4 3
61Reading bank 4:
62
63Word 0x00000003: 00000004
64
65,which matches the ethaddr value:
66=> echo ${ethaddr}
6700:04:9f:02:77:72
68
69Some other useful hints:
70
71- The 'bank' and 'word' numbers can be easily obtained from the mx6 Reference
72Manual. For the mx6quad case, please check the "46.5 OCOTP Memory Map/Register
73Definition" from the "i.MX 6Dual/6Quad Applications Processor Reference Manual,
74Rev. 1, 04/2013" document. For example, for the MAC fuses we have:
75
76Address:
7721B_C620 Value of OTP Bank4 Word2 (MAC Address)(OCOTP_MAC0)
78
7921B_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
84Reading bank 4:
85
86Word 0x00000002: 9f027772 00000004
Stefano Babic40f48392015-12-11 17:30:42 +010087
882. Using imx_usb_loader for first install with SPL
89--------------------------------------------------
90
91imx_usb_loader is a very nice tool by BoundaryDevice that
92allow to install U-Boot without a JTAG debugger, using
93the USB boot mode as described in the manual. It is
94a replacement for Freescale's MFGTOOLS.
95
96The sources can be found here:
97
98 https://github.com/boundarydevices/imx_usb_loader.git
99
100Booting in USB mode, the i.MX6 announces itself to the Linux Host as:
101
102Bus 001 Device 111: ID 15a2:0061 Freescale Semiconductor, Inc.
103
104imx_usb_loader is able to download a single file (u-boot.imx)
105to the board. For boards without SPL support, it is enough to
106issue the command:
107
108 sudo ../imx_usb_loader/imx_usb -v u-boot.imx
109
110Getting U-Boot when SPL support is active, it requires
111two downloads. imx_usb_loader downloads the SPL into
112OCRAM and starts it. SPL will check for a valid u-boot.img, and
113because it is not found, it will wait for it using the y-modem
114protocol via the console.
115
116A first install is then possible by combining imx_usb_loader with
117another tool such as kermit.
118
119sudo ../imx_usb_loader/imx_usb -v SPL
120kermit kermit_uboot
121
122and kermit_uboot contains something like this (set line should be adjusted):
123
124set line /dev/ttyUSB1
125set speed 115200
126SET CARRIER-WATCH OFF
127set flow-control none
128set handshake none
129set prefixing all
130set file type bin
131set protocol ymodem
132send u-boot.img
133c
134
135The last "c" command tells kermit (from ckermit package in most distros)
136to switch from command line mode to communication mode, and when the
137script is finished, the U-Boot prompt is shown in the same shell.