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diff --git a/docs/plat/marvell/porting.rst b/docs/plat/marvell/porting.rst new file mode 100644 index 00000000..8fc1c1f6 --- /dev/null +++ b/docs/plat/marvell/porting.rst @@ -0,0 +1,163 @@ +TF-A Porting Guide for Marvell Platforms +======================================== + +This section describes how to port TF-A to a customer board, assuming that the +SoC being used is already supported in TF-A. + + +Source Code Structure +--------------------- + +- The customer platform specific code shall reside under ``plat/marvell/<soc family>/<soc>_cust`` + (e.g. 'plat/marvell/a8k/a7040_cust'). +- The platform name for build purposes is called ``<soc>_cust`` (e.g. ``a7040_cust``). +- The build system will reuse all files from within the soc directory, and take only the porting + files from the customer platform directory. + +Files that require porting are located at ``plat/marvell/<soc family>/<soc>_cust`` directory. + + +Armada-70x0/Armada-80x0 Porting +------------------------------- + +SoC Physical Address Map (marvell_plat_config.c) +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +This file describes the SoC physical memory mapping to be used for the CCU, +IOWIN, AXI-MBUS and IOB address decode units (Refer to the functional spec for +more details). + +In most cases, using the default address decode windows should work OK. + +In cases where a special physical address map is needed (e.g. Special size for +PCIe MEM windows, large memory mapped SPI flash...), then porting of the SoC +memory map is required. + +.. note:: + For a detailed information on how CCU, IOWIN, AXI-MBUS & IOB work, please + refer to the SoC functional spec, and under + ``docs/marvell/misc/mvebu-[ccu/iob/amb/io-win].txt`` files. + +boot loader recovery (marvell_plat_config.c) +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +- Background: + + Boot rom can skip the current image and choose to boot from next position if a + specific value (``0xDEADB002``) is returned by the ble main function. This + feature is used for boot loader recovery by booting from a valid flash-image + saved in next position on flash (e.g. address 2M in SPI flash). + + Supported options to implement the skip request are: + - GPIO + - I2C + - User defined + +- Porting: + + Under marvell_plat_config.c, implement struct skip_image that includes + specific board parameters. + + .. warning:: + To disable this feature make sure the struct skip_image is not implemented. + +- Example: + +In A7040-DB specific implementation +(``plat/marvell/a8k/a70x0/board/marvell_plat_config.c``), the image skip is +implemented using GPIO: mpp 33 (SW5). + +Before resetting the board make sure there is a valid image on the next flash +address: + + -tftp [valid address] flash-image.bin + -sf update [valid address] 0x2000000 [size] + +Press reset and keep pressing the button connected to the chosen GPIO pin. A +skip image request message is printed on the screen and boot rom boots from the +saved image at the next position. + +DDR Porting (dram_port.c) +~~~~~~~~~~~~~~~~~~~~~~~~~ + +This file defines the dram topology and parameters of the target board. + +The DDR code is part of the BLE component, which is an extension of ARM Trusted +Firmware (TF-A). + +The DDR driver called mv_ddr is released separately apart from TF-A sources. + +The BLE and consequently, the DDR init code is executed at the early stage of +the boot process. + +Each supported platform of the TF-A has its own DDR porting file called +dram_port.c located at ``atf/plat/marvell/a8k/<platform>/board`` directory. + +Please refer to '<path_to_mv_ddr_sources>/doc/porting_guide.txt' for detailed +porting description. + +The build target directory is "build/<platform>/release/ble". + +Comphy Porting (phy-porting-layer.h or phy-default-porting-layer.h) +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +- Background: + Some of the comphy's parameters value depend on the HW connection between + the SoC and the PHY. Every board type has specific HW characteristics like + wire length. Due to those differences some comphy parameters vary between + board types. Therefore each board type can have its own list of values for + all relevant comphy parameters. The PHY porting layer specifies which + parameters need to be suited and the board designer should provide relevant + values. + + .. seealso:: + For XFI/SFI comphy type there is procedure "rx_training" which eases + process of suiting some of the parameters. Please see :ref:`uboot_cmd` + section: rx_training. + + The PHY porting layer simplifies updating static values per board type, + which are now grouped in one place. + + .. note:: + The parameters for the same type of comphy may vary even for the same + board type, it is because the lanes from comphy-x to some PHY may have + different HW characteristic than lanes from comphy-y to the same + (multiplexed) or other PHY. + +- Porting: + The porting layer for PHY was introduced in TF-A. There is one file + ``drivers/marvell/comphy/phy-default-porting-layer.h`` which contains the + defaults. Those default parameters are used only if there is no appropriate + phy-porting-layer.h file under: ``plat/marvell/<soc + family>/<platform>/board/phy-porting-layer.h``. If the phy-porting-layer.h + exists, the phy-default-porting-layer.h is not going to be included. + + .. warning:: + Not all comphy types are already reworked to support the PHY porting + layer, currently the porting layer is supported for XFI/SFI and SATA + comphy types. + + The easiest way to prepare the PHY porting layer for custom board is to copy + existing example to a new platform: + + - cp ``plat/marvell/a8k/a80x0/board/phy-porting-layer.h`` "plat/marvell/<soc family>/<platform>/board/phy-porting-layer.h" + - adjust relevant parameters or + - if different comphy index is used for specific feature, move it to proper table entry and then adjust. + + .. note:: + The final table size with comphy parameters can be different, depending + on the CP module count for given SoC type. + +- Example: + Example porting layer for armada-8040-db is under: + ``plat/marvell/a8k/a80x0/board/phy-porting-layer.h`` + + .. note:: + If there is no PHY porting layer for new platform (missing + phy-porting-layer.h), the default values are used + (drivers/marvell/comphy/phy-default-porting-layer.h) and the user is + warned: + + .. warning:: + "Using default comphy parameters - it may be required to suit them for + your board". |