[U-Boot] [RFC PATCH 00/13] Nexell S5P6818 SoC support

Lukasz Majewski
2017-11-30T10:01:12Z

Hi Andre,

> Hi,
>
> this is a first draft of the things Amit and I have been working on in
> the last months. It introduces support for an SoC called "Nexell
> S5P6818". This is an Octa-core ARMv8 SoC with Cortex-A53 cores, which
> apparently is closely related to (older) Samsung SoCs. Many
> peripherals are compatible to Samsung IP (UART, MMC, Ethernet,
> timers, ...), but some core peripherals like the clocks and the pin
> controller seem to be completely different. We used the NanoPi M3
> board [1] for testing, which uses this SoC along with the usual
> suspects of on-board components and connectors. This port is done
> completely from scratch, by just looking at the manual. This allows a
> much cleaner and modern U-Boot support than the BSP code.
>
> The ARM Generic Timer (aka. arch timer) does not seem to work on this
> SoC. Ideally there would be some (hidden?) register enabling the
> right clock source, though we haven't found one (yet). But as also
> other code for this SoC out there on the net does not seem to be able
> to use the arch timer, I am not too hopeful here. While this does not
> impose a real problem to U-Boot (patch 3/13 takes care of that), it
> is a showstopper for mainline arm64 Linux, which heavily relies on
> the arch timer (since it's a mandatory part of the ARMv8
> architecture). There is only a very small chance that the arch timer
> ever becomes optional in the mainline arm64 kernel. However our
> arm(32) kernel ports works quite nicely so far, also a (hacked) arm64
> kernel boots to the prompt. We will submit Linux patches at a later
> time.
>
> We would be grateful to get some comments on the patches.
> The first five patches adapt existing code to simplify support for
> this SoC. The following six patches then successively enable and add
> SoC support, culmulating in the addition of a nanopi_m3_defconfig
> file in patch 11/13. The SoC support code is actually architecture
> agnostic, though up until the last patch it generates an AArch64
> binary. To overcome the problems with the arch timer mentioned above,
> the final patch switches the port over to AArch32, which can more
> naturally launch arm kernels.
>
> This code so far does not include an SPL, instead it relies on some
> vendor provided code to initialise the DRAM and load U-Boot proper.
> The original BSP code provided a binary blob for that (called
> "secondboot"), although there is some GPLed version of that available
> on github([2]). We can load a 32-bit U-Boot with both the vendor blob
> and Rafaello's GPL version, the 64-bit version is only usable with
> the GPL code. Instruction on how to create a bootable SD card are
> contained in the arch/arm/mach-nexell/README file.
>
> We would be very grateful to get some first feedback on those patches
> and the approach in general taken here.

Just to ask - why it is not possible to add this to:

/arch/arm/mach-exynos ? And start new mach-nexell ?

As fair as I remember, many Samsung SoCs (especially S5P) share IP
blocks, so maybe there is a place for unification?

Also, it would be quite challenging to support first armv8 Samsung soc
in the current directory structure.....

+CC Jaehoon - who may have some comments here.

>
> Cheers,
> Andre.
>
> [1] http://nanopi.io/nanopi-m3.html
> [2] https://github.com/rafaello7/bl1-nanopi-m3
>
> Amit Singh Tomar (4):
> reset: add driver for generic reset controllers
> mmc: add MMC (glue) driver for Nexell SoCs
> arm: nexell: add ARM64 MMU regions
> arm: nexell: add timer support
>
> Andre Przywara (9):
> serial: s5p: rework Samsung UART driver to get rid of uart.h
> serial: S5P/Samsung: refactor and Kconfig-ize UART selection
> arm: move SYS_ARCH_TIMER to KConfig
> arm: add basic framework for Nexell S5P6818 support
> arm: nexell: embed NSIH header
> arm: nexell: add UART support
> arm: nexell: add preliminary S5P6818 SoC device tree
> arm: add NanoPi M3 board support
> arm: nexell: switch to 32-bit
>
> arch/arm/Kconfig | 29 +++++
> arch/arm/Makefile | 1 +
> arch/arm/cpu/armv8/Makefile | 2 +-
> arch/arm/dts/s5p6818-nanopi-m3.dts | 30 +++++
> arch/arm/dts/s5p6818.dtsi | 196
> ++++++++++++++++++++++++++++++
> arch/arm/dts/s5pc1xx-goni.dts | 2 +-
> arch/arm/dts/s5pc1xx-smdkc100.dts | 2 +-
> arch/arm/include/asm/arch-nexell/boot0.h | 35 ++++++
> arch/arm/include/asm/arch-nexell/clk.h | 15 +++
> arch/arm/include/asm/arch-nexell/pwm.h | 62 ++++++++++
> arch/arm/mach-exynos/include/mach/uart.h | 44 -------
> arch/arm/mach-imx/mx7ulp/Kconfig | 1 +
> arch/arm/mach-nexell/Kconfig | 9 ++
> arch/arm/mach-nexell/Makefile | 10 ++
> arch/arm/mach-nexell/README | 49 ++++++++
> arch/arm/mach-nexell/board.c | 128 +++++++++++++++++++
> arch/arm/mach-nexell/mmu-arm64.c | 39 ++++++
> arch/arm/mach-s5pc1xx/Kconfig | 2 +
> arch/arm/mach-s5pc1xx/include/mach/uart.h | 44 -------
> configs/nanopi_m3_defconfig | 12 ++
> drivers/mmc/Kconfig | 8 ++
> drivers/mmc/Makefile | 1 +
> drivers/mmc/nexell_dw_mmc.c | 159
> ++++++++++++++++++++++++ drivers/reset/Kconfig
> | 6 + drivers/reset/Makefile | 1 +
> drivers/reset/reset-generic.c | 111 +++++++++++++++++
> drivers/serial/Kconfig | 6 +
> drivers/serial/Makefile | 2 +-
> drivers/serial/serial_s5p.c | 45 ++++++-
> include/configs/mx7ulp_evk.h | 1 -
> include/configs/s5p6818.h | 35 ++++++
> include/configs/ti_armv7_keystone2.h | 1 -
> scripts/config_whitelist.txt | 1 - 33 files changed,
> 989 insertions(+), 100 deletions(-) create mode 100644
> arch/arm/dts/s5p6818-nanopi-m3.dts create mode 100644
> arch/arm/dts/s5p6818.dtsi create mode 100644
> arch/arm/include/asm/arch-nexell/boot0.h create mode 100644
> arch/arm/include/asm/arch-nexell/clk.h create mode 100644
> arch/arm/include/asm/arch-nexell/pwm.h delete mode 100644
> arch/arm/mach-exynos/include/mach/uart.h create mode 100644
> arch/arm/mach-nexell/Kconfig create mode 100644
> arch/arm/mach-nexell/Makefile create mode 100644
> arch/arm/mach-nexell/README create mode 100644
> arch/arm/mach-nexell/board.c create mode 100644
> arch/arm/mach-nexell/mmu-arm64.c delete mode 100644
> arch/arm/mach-s5pc1xx/include/mach/uart.h create mode 100644
> configs/nanopi_m3_defconfig create mode 100644
> drivers/mmc/nexell_dw_mmc.c create mode 100644
> drivers/reset/reset-generic.c create mode 100644
> include/configs/s5p6818.h
>

Best regards,

Lukasz Majewski

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