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https://github.com/AsahiLinux/u-boot
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b887f0a68e
Currently the High Assurance Boot procedure is documented in two places: - doc/README.imx6 - doc/README.mxc_hab It is better to consolidate all HAB related information into README.mxc_hab file, so move the content from README.imx6 to README.mxc_hab. Signed-off-by: Breno Lima <breno.lima@nxp.com> Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
115 lines
3 KiB
Text
115 lines
3 KiB
Text
U-Boot for Freescale i.MX6
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This file contains information for the port of U-Boot to the Freescale i.MX6
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SoC.
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1. CONVENTIONS FOR FUSE ASSIGNMENTS
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-----------------------------------
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1.1 MAC Address: It is stored in fuse bank 4, with the 32 lsbs in word 2 and the
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16 msbs in word 3[15:0].
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For i.MX6SX and i.MX6UL, they have two MAC addresses. The second MAC address
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is stored in fuse bank 4, with the 16 lsb in word 3[31:16] and the 32 msbs in
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word 4.
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Example:
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For reading the MAC address fuses on a MX6Q:
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- The MAC address is stored in two fuse addresses (the fuse addresses are
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described in the Fusemap Descriptions table from the mx6q Reference Manual):
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0x620[31:0] - MAC_ADDR[31:0]
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0x630[15:0] - MAC_ADDR[47:32]
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In order to use the fuse API, we need to pass the bank and word values, which
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are calculated as below:
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Fuse address for the lower MAC address: 0x620
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Base address for the fuses: 0x400
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(0x620 - 0x400)/0x10 = 0x22 = 34 decimal
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As the fuses are arranged in banks of 8 words:
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34 / 8 = 4 and the remainder is 2, so in this case:
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bank = 4
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word = 2
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And the U-Boot command would be:
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=> fuse read 4 2
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Reading bank 4:
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Word 0x00000002: 9f027772
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Doing the same for the upper MAC address:
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Fuse address for the upper MAC address: 0x630
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Base address for the fuses: 0x400
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(0x630 - 0x400)/0x10 = 0x23 = 35 decimal
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As the fuses are arranged in banks of 8 words:
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35 / 8 = 4 and the remainder is 3, so in this case:
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bank = 4
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word = 3
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And the U-Boot command would be:
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=> fuse read 4 3
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Reading bank 4:
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Word 0x00000003: 00000004
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,which matches the ethaddr value:
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=> echo ${ethaddr}
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00:04:9f:02:77:72
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Some other useful hints:
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- The 'bank' and 'word' numbers can be easily obtained from the mx6 Reference
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Manual. For the mx6quad case, please check the "46.5 OCOTP Memory Map/Register
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Definition" from the "i.MX 6Dual/6Quad Applications Processor Reference Manual,
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Rev. 1, 04/2013" document. For example, for the MAC fuses we have:
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Address:
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21B_C620 Value of OTP Bank4 Word2 (MAC Address)(OCOTP_MAC0)
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21B_C630 Value of OTP Bank4 Word3 (MAC Address)(OCOTP_MAC1)
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- The command '=> fuse read 4 2 2' reads the whole MAC addresses at once:
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=> fuse read 4 2 2
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Reading bank 4:
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Word 0x00000002: 9f027772 00000004
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2. Using imx_usb_loader for first install with SPL
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--------------------------------------------------
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imx_usb_loader is a very nice tool by Boundary Devices that
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allow to install U-Boot without a JTAG debugger, using
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the USB boot mode as described in the manual. It is
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a replacement for Freescale's MFGTOOLS.
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The sources can be found here:
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https://github.com/boundarydevices/imx_usb_loader.git
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Booting in USB mode, the i.MX6 announces itself to the Linux Host as:
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Bus 001 Device 111: ID 15a2:0061 Freescale Semiconductor, Inc.
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imx_usb_loader is able to download a single file (u-boot.imx)
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to the board. For boards without SPL support, it is enough to
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issue the command:
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sudo ../imx_usb_loader/imx_usb -v u-boot.imx
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In order to load SPL and u-boot.img via imx_usb_loader tool,
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please refer to doc/README.sdp.
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