| # |
| # Copyright (C) 2015 Google. Inc |
| # Written by Simon Glass <sjg@chromium.org> |
| # |
| # SPDX-License-Identifier: GPL-2.0+ |
| # |
| |
| U-Boot on Rockchip |
| ================== |
| |
| There are several repositories available with versions of U-Boot that support |
| many Rockchip devices [1] [2]. |
| |
| The current mainline support is experimental only and is not useful for |
| anything. It should provide a base on which to build. |
| |
| So far only support for the RK3288 is provided. |
| |
| |
| Prerequisites |
| ============= |
| |
| You will need: |
| |
| - Firefly RK3288 baord |
| - Power connection to 5V using the supplied micro-USB power cable |
| - Separate USB serial cable attached to your computer and the Firefly |
| (connect to the micro-USB connector below the logo) |
| - rkflashtool [3] |
| - openssl (sudo apt-get install openssl) |
| - Serial UART connection [4] |
| - Suitable ARM cross compiler, e.g.: |
| sudo apt-get install gcc-4.7-arm-linux-gnueabi |
| |
| |
| Building |
| ======== |
| |
| At present three RK3288 boards are supported: |
| |
| - Firefly RK3288 - use firefly-rk3288 configuration |
| - Radxa Rock 2 - also uses firefly-rk3288 configuration |
| - Haier Chromebook - use chromebook_jerry configuration |
| |
| one RK3036 board is support: |
| |
| - EVB RK3036 - use evb-rk3036_defconfig configuration |
| |
| For example: |
| |
| CROSS_COMPILE=arm-linux-gnueabi- make O=firefly firefly-rk3288_defconfig all |
| |
| (or you can use another cross compiler if you prefer) |
| |
| Note that the Radxa Rock 2 uses the Firefly configuration for now as |
| device tree files are not yet available for the Rock 2. Clearly the two |
| have hardware differences, so this approach will break down as more drivers |
| are added. |
| |
| |
| Writing to the board with USB |
| ============================= |
| |
| For USB to work you must get your board into ROM boot mode, either by erasing |
| your MMC or (perhaps) holding the recovery button when you boot the board. |
| To erase your MMC, you can boot into Linux and type (as root) |
| |
| dd if=/dev/zero of=/dev/mmcblk0 bs=1M |
| |
| Connect your board's OTG port to your computer. |
| |
| To create a suitable image and write it to the board: |
| |
| ./firefly-rk3288/tools/mkimage -n rk3288 -T rkimage -d \ |
| ./firefly-rk3288/spl/u-boot-spl-dtb.bin out && \ |
| cat out | openssl rc4 -K 7c4e0304550509072d2c7b38170d1711 | rkflashtool l |
| |
| If all goes well you should something like: |
| |
| U-Boot SPL 2015.07-rc1-00383-ge345740-dirty (Jun 03 2015 - 10:06:49) |
| Card did not respond to voltage select! |
| spl: mmc init failed with error: -17 |
| ### ERROR ### Please RESET the board ### |
| |
| You will need to reset the board before each time you try. Yes, that's all |
| it does so far. If support for the Rockchip USB protocol or DFU were added |
| in SPL then we could in principle load U-Boot and boot to a prompt from USB |
| as several other platforms do. However it does not seem to be possible to |
| use the existing boot ROM code from SPL. |
| |
| |
| Booting from an SD card |
| ======================= |
| |
| To write an image that boots from an SD card (assumed to be /dev/sdc): |
| |
| ./firefly-rk3288/tools/mkimage -n rk3288 -T rksd -d \ |
| firefly-rk3288/spl/u-boot-spl-dtb.bin out && \ |
| sudo dd if=out of=/dev/sdc seek=64 && \ |
| sudo dd if=firefly-rk3288/u-boot-dtb.img of=/dev/sdc seek=256 |
| |
| This puts the Rockchip header and SPL image first and then places the U-Boot |
| image at block 256 (i.e. 128KB from the start of the SD card). This |
| corresponds with this setting in U-Boot: |
| |
| #define CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR 256 |
| |
| Put this SD (or micro-SD) card into your board and reset it. You should see |
| something like: |
| |
| U-Boot SPL 2015.07-rc1-00383-ge345740-dirty (Jun 03 2015 - 11:04:40) |
| |
| |
| U-Boot 2015.07-rc1-00383-ge345740-dirty (Jun 03 2015 - 11:04:40) |
| |
| DRAM: 2 GiB |
| MMC: |
| Using default environment |
| |
| In: serial@ff690000 |
| Out: serial@ff690000 |
| Err: serial@ff690000 |
| => |
| |
| For evb_rk3036 board: |
| ./evb-rk3036/tools/mkimage -n rk3036 -T rksd -d evb-rk3036/spl/u-boot-spl.bin out && \ |
| cat evb-rk3036/u-boot-dtb.bin >> out && \ |
| sudo dd if=out of=/dev/sdc seek=64 |
| |
| Note: rk3036 SDMMC and debug uart use the same iomux, so if you boot from SD, the |
| debug uart must be disabled |
| |
| Booting from SPI |
| ================ |
| |
| To write an image that boots from SPI flash (e.g. for the Haier Chromebook): |
| |
| ./chromebook_jerry/tools/mkimage -n rk3288 -T rkspi \ |
| -d chromebook_jerry/spl/u-boot-spl-dtb.bin spl.bin && \ |
| dd if=spl.bin of=spl-out.bin bs=128K conv=sync && \ |
| cat spl-out.bin chromebook_jerry/u-boot-dtb.img >out.bin && \ |
| dd if=out.bin of=out.bin.pad bs=4M conv=sync |
| |
| This converts the SPL image to the required SPI format by adding the Rockchip |
| header and skipping every 2KB block. Then the U-Boot image is written at |
| offset 128KB and the whole image is padded to 4MB which is the SPI flash size. |
| The position of U-Boot is controlled with this setting in U-Boot: |
| |
| #define CONFIG_SYS_SPI_U_BOOT_OFFS (128 << 10) |
| |
| If you have a Dediprog em100pro connected then you can write the image with: |
| |
| sudo em100 -s -c GD25LQ32 -d out.bin.pad -r |
| |
| When booting you should see something like: |
| |
| U-Boot SPL 2015.07-rc2-00215-g9a58220-dirty (Jun 23 2015 - 12:11:32) |
| |
| |
| U-Boot 2015.07-rc2-00215-g9a58220-dirty (Jun 23 2015 - 12:11:32 -0600) |
| |
| Model: Google Jerry |
| DRAM: 2 GiB |
| MMC: |
| Using default environment |
| |
| In: serial@ff690000 |
| Out: serial@ff690000 |
| Err: serial@ff690000 |
| => |
| |
| |
| Future work |
| =========== |
| |
| Immediate priorities are: |
| |
| - GPIO (driver exists but is lightly tested) |
| - I2C (driver exists but is non-functional) |
| - USB host |
| - USB device |
| - PMIC and regulators (only ACT8846 is supported at present) |
| - LCD and HDMI |
| - Run CPU at full speed |
| - Ethernet |
| - NAND flash |
| - Support for other Rockchip parts |
| - Boot U-Boot proper over USB OTG (at present only SPL works) |
| |
| |
| Development Notes |
| ================= |
| |
| There are plenty of patches in the links below to help with this work. |
| |
| [1] https://github.com/rkchrome/uboot.git |
| [2] https://github.com/linux-rockchip/u-boot-rockchip.git branch u-boot-rk3288 |
| [3] https://github.com/linux-rockchip/rkflashtool.git |
| [4] http://wiki.t-firefly.com/index.php/Firefly-RK3288/Serial_debug/en |
| |
| rkimage |
| ------- |
| |
| rkimage.c produces an SPL image suitable for sending directly to the boot ROM |
| over USB OTG. This is a very simple format - just the string RK32 (as 4 bytes) |
| followed by u-boot-spl-dtb.bin. |
| |
| The boot ROM loads image to 0xff704000 which is in the internal SRAM. The SRAM |
| starts at 0xff700000 and extends to 0xff718000 where we put the stack. |
| |
| rksd |
| ---- |
| |
| rksd.c produces an image consisting of 32KB of empty space, a header and |
| u-boot-spl-dtb.bin. The header is defined by 'struct header0_info' although |
| most of the fields are unused by U-Boot. We just need to specify the |
| signature, a flag and the block offset and size of the SPL image. |
| |
| The header occupies a single block but we pad it out to 4 blocks. The header |
| is encoding using RC4 with the key 7c4e0304550509072d2c7b38170d1711. The SPL |
| image can be encoded too but we don't do that. |
| |
| The maximum size of u-boot-spl-dtb.bin which the boot ROM will read is 32KB, |
| or 0x40 blocks. This is a severe and annoying limitation. There may be a way |
| around this limitation, since there is plenty of SRAM, but at present the |
| board refuses to boot if this limit is exceeded. |
| |
| The image produced is padded up to a block boundary (512 bytes). It should be |
| written to the start of an SD card using dd. |
| |
| Since this image is set to load U-Boot from the SD card at block offset, |
| CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR, dd should be used to write |
| u-boot-dtb.img to the SD card at that offset. See above for instructions. |
| |
| rkspi |
| ----- |
| |
| rkspi.c produces an image consisting of a header and u-boot-spl-dtb.bin. The |
| resulting image is then spread out so that only the first 2KB of each 4KB |
| sector is used. The header is the same as with rksd and the maximum size is |
| also 32KB (before spreading). The image should be written to the start of |
| SPI flash. |
| |
| See above for instructions on how to write a SPI image. |
| |
| rkmux.py |
| -------- |
| |
| You can use this script to create #defines for SoC register access. See the |
| script for usage. |
| |
| |
| Device tree and driver model |
| ---------------------------- |
| |
| Where possible driver model is used to provide a structure to the |
| functionality. Device tree is used for configuration. However these have an |
| overhead and in SPL with a 32KB size limit some shortcuts have been taken. |
| In general all Rockchip drivers should use these features, with SPL-specific |
| modifications where required. |
| |
| |
| -- |
| Simon Glass <sjg@chromium.org> |
| 24 June 2015 |