2016-06-08 08:50:20 +00:00
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Board information
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-----------------
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The SBC produced by Phytec has a SOM based on a i.MX6Q.
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The SOM is sold in two versions, with eMMC or with NAND. Support
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here is for the SOM with NAND.
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The evaluation board "phyBoard-Mira" is thought to be used
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together with the SOM.
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More information on the board can be found on manufacturer's
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website:
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http://www.phytec.de/produkt/single-board-computer/phyboard-mira/
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http://www.phytec.de/fileadmin/user_upload/images/content/1.Products/SOMs/phyCORE-i.MX6/L-808e_1.pdf
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Building U-Boot
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-------------------------------
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$ make pcm058_defconfig
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$ make
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This generates the artifacts SPL and u-boot.img.
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The SOM can boot from NAND or from SD-Card, having the SPI-NOR
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as second option.
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The dip switch "DIP-1" on the board let choose between
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NAND and SD.
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DIP-1 set to off: Boot first from NAND, then try SPI
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DIP-1 set to on: Boot first from SD, then try SPI
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The bootloader was tested with DIP-1 set to on. If a SD-card
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is present, then the RBL tries to load SPL from the SD Card, if not,
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RBL loads from SPI-NOR. The SPL tries then to load from the same
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device where SPL was loaded (SD or SPI). Booting from NAND is
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not supported.
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2020-05-19 12:01:43 +00:00
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Flashing U-Boot onto an SD card
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-------------------------------
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After a successful build, the generated SPL and U-boot binaries can be copied
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to an SD card. Adjust the SD card device as necessary:
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$ sudo dd if=u-boot-with-spl.imx of=/dev/mmcblk0 bs=1k seek=1
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This is equivalent to separately copying the SPL and U-boot using:
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$ sudo dd if=SPL of=/dev/mmcblk0 bs=1k seek=1
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$ sudo dd if=u-boot-dtb.img of=/dev/mmcblk0 bs=1k seek=197
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The default bootscripts expect a kernel fit-image file named "fitImage" in the
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first partition and Linux ext4 rootfs in the second partition.
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Flashing U-boot to the SPI Flash, for booting Linux from NAND
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-------------------------------------------------------------
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The SD card created above can also be used to install the SPL and U-boot into
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the SPI flash. Boot U-boot from the SD card as above, and stop at the autoboot.
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Then, clear the SPI flash:
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=> sf probe
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=> sf erase 0x0 0x1000000
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Load the SPL from raw MMC into memory and copy to the SPI. The SPL is maximum
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392*512-byte blocks in size therefore 0x188 blocks, totaling 0x31000 bytes:
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=> mmc read ${loadaddr} 0x2 0x188
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=> sf write ${loadaddr} 0x400 0x31000
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Load the U-boot binary into memory and copy to the SPI. U-boot should fit into
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640KiB, so 0x500 512-byte blocks, totalling 0xA0000 bytes:
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=> mmc read ${loadaddr} 0x18a 0x500
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=> sf write ${loadaddr} 0x40000 0xA0000
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The default NAND bootscripts expect a single MTD partition named "rootfs",
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which in turn contains the UBI volumes "fit" (which contains the kernel fit-
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image) and "root" (which contains a ubifs root filesystem).
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The "bootm_size" variable in the environment
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--------------------------------------------
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By default, U-boot relocates the device tree towards the upper end of the RAM,
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which kernels using CONFIG_HIGHMEM=y may not be able to access during early
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boot. With the bootm_size variable set to 0x30000000, U-boot relocates the
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device tree to below this address instead.
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