Re: [PATCH v2] Porting barebox to a new SoC

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

Hi Lior,

On 30.05.23 22:10, Lior Weintraub wrote:
> Hello Ahmad,
> 
> Thanks again for your kind support!
> Your comments helped me progress and the current situation is as follows:
> Our QEMU Spider machine is running a BL1.elf file using the following command:
> QEMU_AUDIO_DRV=none qemu-system-aarch64 -M spider-soc -smp 1 -m 128M -nographic \
> 	-device loader,file=BL1.elf -cpu cortex-a53,rvbar=0xC004000000 \
> 	-d unimp -semihosting-config enable=on,target=native \
> 	-monitor telnet:localhost:1235,server,nowait \
> 	-gdb tcp::1236
> 
> The BL1.elf is our BootROM application that runs from ROM address 0xC004000000.
> Just for debugging purpose we've increased the ROM size so it can include the images/barebox-spider-mk1-evk.img (as a const array).
> BL1 then copy it (using memcpy) to address 0 and jumps there for execution.

Sounds ok.

> On the real ASIC this address will be the DRAM and indeed will need to be initialized before the copy but here on QEMU it is not required.

I see. You could still have your bootrom move barebox into SRAM and then

  barebox_arm_entry(DRAM_ADDR, SZ_128M, __dtb_spider_mk1_evk_start); 

To have PBL extract barebox to DRAM. Even if you don't need need DRAM
setup in QEMU, the flow would be similar to what you will have on actual
silicon.

> The lowlevel.c of spider-evk was modified to use DRAM_ADDR 0x400000 (4MB from start) and MY_STACK_TOP was set to 0x8000000 (128M).

That's not needed. While you don't have control where barebox PBL will be located
(depends on BootROM), barebox will extract itself to the end of DRAM without
overwriting itself, so you can just use DRAM_ADDR 0 normally. Eventually, stack
top should go into SRAM, but anywhere that works is ok.

> In addition, I implemented putc_ll (currently hard-coded in include/debug_ll.h) and opened log level to VERBOSE_DEBUG (currently just hard-coded in printk.h).

There's CONFIG_DEBUG_PBL you can enable to get all these messages by default.

> I see the following (which makes sense) logs on QEMU terminal:
> uncompress.c: memory at 0x00400000, size 0x00200000
> uncompress.c: uncompressing barebox binary at 0x0000000000002200 (size 0x0001d3b2) to 0x00400000 (uncompressed size: 0x000373d0)

Why pass only 2M to barebox_arm_entry? While this need not be the whole of RAM, this
initial memory is what barebox will use for itself including its final stack and
malloc area. barebox will also not place itself into the last 1M AFAIK, so 2M
may not work ok. You should use the minimum possible RAM here or if you can detect
in PBL how much RAM you have or just the whole RAM bank. I am not sure anything lower
than SZ_4M would work ok. (Note this is DRAM size, not SRAM. barebox PBL is fine being
called from 64K SRAMs, it just needs DRAM to extract to).
 
> I then connect with aarch64-none-elf-gdb, load the barebox symbols (to 0x400000) and check the current execution state (program counter and stack).
> Looks like the code is stuck on function register_autoboot_vars:
> sp             0x5f7e60            0x5f7e60
> pc             0x401264            0x401264 <register_autoboot_vars+24>
> 
> Few observations:
> 1. The PBL was using stack top located on 0x8000000 (which is MY_STACK_TOP). Found it be causing a breakpoint on the PBL.
> 2. Barebox uses a stack top on 0x600000 which is probably calculated from my new DRAM_ADDR and SZ_2M given to the function call:
>     barebox_arm_entry(DRAM_ADDR, SZ_2M, __dtb_spider_mk1_evk_start); 
> 
> This is great! I am starting to find my way.

:) Ye, the ENTRY_FUNCTION_WITHSTACK is only when the BootROM doesn't enter
with a valid stack pointer. It's overwritten as soon as barebox is told
about the initial memory layout (with barebox_arm_entry).

> When the barebox execution didn't print anything to the terminal I remembered that we used a place holder on the dtsi for the uart.
> So now I changed it to:
> uart0: serial@d000307000 {
>        compatible = "arm,pl011", "arm,primecell";
>        reg = <0xd0 0x307000 0 0x1000>;
> }
> (Our QEMU UART is currently using pl011 device.)

Looks ok. Don't forget to enable the driver (via make menuconfig).

> After some time (trying to debug by enabling MMU but then reverted the code back), I got to a point that when I try to run again I am getting an exception.
> I can swear all code changes were reverted back to the point where I saw the barebox stuck on register_autoboot_vars but now it just cases an exception.
> The exception vector code is located on our ROM (part of BL1 code) and the logs shows that the link register has the value 0x401218 which suggest the following code:
> 0000000000001200 <load_environment>:
> 1200:	a9be7bfd 	stp	x29, x30, [sp, #-32]!
> 1204:	910003fd 	mov	x29, sp
> 1208:	a90153f3 	stp	x19, x20, [sp, #16]
> 120c:	94000a07 	bl	3a28 <default_environment_path_get>
> 1210:	d00000f3 	adrp	x19, 1f000 <do_cpuinfo+0x1f0>
> 1214:	912a7273 	add	x19, x19, #0xa9c
> 1218:	aa0003f4 	mov	x20, x0
> 
> Any ideas or suggestions how to proceed with the debugging?

You shouldn't need to touch the MMU code. If your initial memory setup
is wonky, you may end up overwriting stuff. Try again with bigger memory.

> BTW, to answer your questions:
> The SRAM of 4MB is the only one we have because we assumed it is only for BootROM to load a PBL

Ok. Sometimes there are SRAMs for use with DMA. I asked, because a SRAM in the first 4M
would lend itself nicely as stack, but if there is none, we can adjust
ENTRY_FUNCTION_WITHSTACK to accept a 64-bit parameter.

Cheers,
Ahmad

> Thank you very much,
> Cheers,
> Lior.
> 
>  
>> -----Original Message-----
>> From: Ahmad Fatoum <a.fatoum@pengutronix.de>
>> Sent: Monday, May 29, 2023 10:03 PM
>> To: Lior Weintraub <liorw@pliops.com>; Ahmad Fatoum <ahmad@a3f.at>;
>> barebox@lists.infradead.org
>> Subject: Re: [PATCH v2] Porting barebox to a new SoC
>>
>> CAUTION: External Sender
>>
>> Hello Lior,
>>
>> On 29.05.23 15:34, Lior Weintraub wrote:
>>> Hi Ahmad,
>>>
>>> I have revised the addresses and used DRAM address @ 0 instead:
>>> #define UARTBASE        (0xD000307000)
>>> #define DRAM_ADDR       (0x00000000)
>>> #define MY_STACK_TOP    (0x00000000 + SZ_2M) // Set the stack 2MB from
>> DRAM start
>>
>> Is DRAM configured by the time barebox runs? If not, you should keep stack
>> top
>> in SRAM, until you have setup memory in prebootloader (PBL). Is the 4M
>> SRAM
>> the only on-chip SRAM you have?
>>
>>> static inline void spider_serial_putc(void *base, int c)
>>> {
>>>     *((volatile unsigned *)base) = c;
>>
>> There's a helper for that: writel(c, base); In barebox, it's equivalent
>> to the volatile access, but in Linux it involves a write memory barrier.
>> We try to write code in barebox, so it's easily reusable in Linux (and
>> the other way round).
>>
>>> }
>>>
>>> I will try to test it on QEMU using an initial QEMU machine we made for
>> Spider.
>>> In this machine we only have 3 memory regions and a PL011 UART:
>>> spider_soc_memories soc_memories[] = {
>>>     {.name = "SPIDER_GPRAM",   .add = 0xC000000000ULL, .size = 4 * MiB},
>>>     {.name = "SPIDER_ROM",     .add = 0xC004000000ULL, .size = 128 * KiB},
>>>     {.name = "SPIDER_DRAM",    .add = 0x0000000000ULL, .size = 1 * GiB},
>>> };
>>>
>>> This special QEMU machine can run our BL1 code from "ROM" address (we
>> set the RVBAR to point there).
>>> So my idea is to test the barebox image by the following steps:
>>> 1. Modify the QEMU code to have a "ROM" with the size of 128M.
>>> 2. Compile our BL1 code to include the barebox.bin as a const array, copy it
>> to "DRAM" @ address 0 and jump there.
>>
>> Why not map QEMU -bios option to SRAM? (Or DRAM directly, if it needs no
>> special setup from
>> barebox side).
>>
>>> For this to work I wanted to understand how to call (i.e. what arguments to
>> pass) to barebox.
>>
>> barebox doesn't expect any arguments, because most BootROMs don't pass
>> anything useful.
>> Some pass information about bootsource though, so that's why the
>> ENTRY_FUNCTION has
>> r0, r1 and r2 as parameters, but you need not use them.
>>
>>> So I checked the barebox.map and found the function "start" on address 0.
>>
>> You may know that Linux on some platforms comes with a decompressor that
>> is glued to the
>> front of the kernel image and extracts the compressed kernel image. barebox
>> has the same
>> concept. The prebootloader is uncompressed and runs (starting from
>> ENTRY_FUNCTION) and
>> then does some early setup (e.g. enable clocks, configure PMIC, setup DRAM,
>> load secure
>> monitor (BL31), ...etc.) and then it decompresses barebox proper into DRAM.
>>
>> barebox.bin <- barebox proper. You don't usually need that.
>> barebox.elf <- ELF binary for the above (for gdb)
>> barebox.map <- map file of the above
>>
>> images/barebox-spider-mk1-evk.img   <- complete barebox image (PBL +
>> barebox proper)
>> images/start_spider_mk1_evk.pbl     <- ELF image for the above
>> images/start_spider_mk1_evk.pbl.map <- map file of the above
>>
>> If you want to follow barbeox from the start, begin at start_spider_mk1_evk.
>>
>>> Then I went to arch/arm/cpu/start.c and realized that the code is compiled
>> with CONFIG_PBL_IMAGE.
>>> In that case I assume I need to pass 3 arguments and use this function
>> prototype:
>>> void start(unsigned long membase, unsigned long memsize, void
>> *boarddata);
>>
>> barebox prebootloader takes care of this, so you don't need to do anything.
>>
>>> Few questions:
>>> 1. Will that call work:
>>>     typedef void (*barebox_start)(unsigned long , unsigned long , void *);
>>>     #define DRAM_START  (0)
>>>     barebox_start p_barebox = (barebox_start)DRAM_START;
>>>     p_barebox(DRAM_START, DRAM_START+SZ_2M, (void
>> *)(DRAM_START+SZ_4M));
>>>     This assumes that my BL1 code also copied the device tree (barebox-dt-
>> 2nd.img? start_dt_2nd.pblb? start_spider_mk1_evk.pblb?)
>>
>> The device tree is built into the PBL and passed to barebox proper. This
>> allows us to use the same barebox proper binary and link it with a different
>> prebootloader for each SoC/board, all in the same build.
>>
>> barebox-dt-2nd.img is a special image that looks exactly like a Linux kernel:
>>
>>   images/barebox-dt-2nd.img: Linux kernel ARM64 boot executable Image,
>> little-endian, 4K pages
>>
>> and can thus be used for booting for easy chainloading from other
>> bootloaders or for running
>> with QEMU -kernel. You shouldn't need it right now.
>>
>>> 2. Do I want to have my code compiled with CONFIG_PBL_IMAGE?
>>>     If I understand correctly, it means that my code will provide a PBL (a.k.a
>> BL2) which will set the DRAM and STACK among other things (MMU?).
>>
>> The patch I sent already builds a PBL. You will need to fill out
>> start_spider_mk1_evk
>> to do all the other early initialization you need. Then you call
>> barebox_arm_entry
>> with device tree and memory size and it will take care to do stack setup in new
>> memory region, MMU setup (if enabled) and chainloading barebox proper.
>>
>> Note that PBL isn't necessary BL2. You can chainload barebox from within
>> barebox (i.e.
>> in EL2 or EL1), which is useful for debugging. You will thus often find PBL code
>> that
>> does
>>
>>   if (current_el() == 3) {
>>         /* Do BL2 setup */
>>         chainload();
>>         __builtin_unreachable();
>>   }
>>
>>   barebox_arm_entry(...)
>>
>> See for example arch/arm/boards/innocomm-imx8mm-wb15/lowlevel.c
>>
>> to see a real-world example of another Cortex-A53.
>>
>>>     In that case I assume it is OK.
>>> 3. If I try to remove it by having CONFIG_PBL_IMAGE=n on spider_defconfig
>> this doesn't do anything
>>>     The build (make spider_defconfig) ignores it and say that " No change to
>> .config ".
>>
>> Another symbol forces it to be enabled. If you are curious, run make
>> menuconfig
>> and then search (/) for the symbol and it will list, whether it's enabled and
>> why:
>>
>>   Selected by [y]:
>>     - PBL_MULTI_IMAGES [=y] && HAVE_PBL_MULTI_IMAGES [=y]
>>
>> I'd suggest you avoid modifying the .config file manually. always use
>> menuconfig.
>>
>>> 4. I also tried to understand how to implement PUTC_LL but not sure I
>> understand.
>>>    4.1 When I set "CONFIG_DEBUG_LL=y" on spider_defconfig it is again not
>> written to .config and I get " No change to .config " message.
>>
>> You must:
>>
>>   - select HAS_DEBUG_LL from MACH_SPIDER
>>   - Add your arch to arch/arm/include/asm/debug_ll.h
>>   - Then implement PUTC_LL in e.g. mach/spider/debug_ll.h
>>
>>>    4.2 Do I need to have my own debug_ll.h file?
>>
>> Yes. See above.
>>
>>> 5. When I make changes to spider_defconfig and try to regenerate the
>> .config and I get " No change to .config " message, does it mean that those
>> macros are "hidden" symbols like you said about the CONFIG_CPU_V8?
>>
>> Yes. Just check menuconfig to see how symbols relate to each other.
>> This is 1:1 like it's in Linux, so it'll come in handy when you do
>> the kernel port too ;)
>>
>>> Apologize for so many questions :-)
>>
>> No problem. Looking forward to your patches ;)
>>
>>
>> Cheers,
>> Ahmad
>>
>>> Cheers,
>>> Lior.
>>>
>>> -----Original Message-----
>>> From: Lior Weintraub
>>> Sent: Sunday, May 28, 2023 11:16 PM
>>> To: Ahmad Fatoum <ahmad@a3f.at>; barebox@lists.infradead.org
>>> Subject: RE: [PATCH v2] Porting barebox to a new SoC
>>>
>>> Hi Ahmad,
>>>
>>> Thank you so much for your kind support!
>>>
>>> Indeed we also have a 16GB DRAM that starts from address 0 (though
>> currently we don't have the controller settings (under development)).
>>>
>>> I also wrote the BootROM (BL1) for this SoC (128KB ROM @ address
>> 0xC004000000).
>>> I understand now that it would be best for me to develop BL2 that will run
>> from our SRAM.
>>>
>>> As this BL2 code is bare-metal I have no problem or limitations with the 40
>> bit addresses.
>>> The BL2 code will initialize the DRAM controller and then copy Barebox image
>> from NOR Flash to address 0 of the DRAM.
>>> Our NOR Flash is 128MB in size and it is accessed via QSPI controller.
>>>
>>> I tried applying your suggested patch but got an error while doing so:
>>> $git apply 0002-Ahmad.patch
>>> 0002-Ahmad.patch:115: trailing whitespace.
>>>       .of_compatible = spider_board_of_match, };
>>> error: corrupt patch at line 117
>>>
>>> After some digging I found that my Outlook probably messed with the patch
>> format (even though I am using text only and no HTML format).
>>> When I went to the web and copied the patch from there (mailing list
>> archive) it was working well (i.e. no compilation error).
>>>
>>> Cheers,
>>> Lior.
>>>
>>> -----Original Message-----
>>> From: Ahmad Fatoum <ahmad@a3f.at>
>>> Sent: Sunday, May 28, 2023 6:38 PM
>>> To: barebox@lists.infradead.org
>>> Cc: Lior Weintraub <liorw@pliops.com>
>>> Subject: [PATCH v2] Porting barebox to a new SoC
>>>
>>> CAUTION: External Sender
>>>
>>> From: Lior Weintraub <liorw@pliops.com>
>>>
>>> Hi,
>>>
>>> I tried to follow the porting guide on https://ddec1-0-en-
>> ctp.trendmicro.com:443/wis/clicktime/v1/query?url=https%3a%2f%2fwww.
>> barebox.org%2fdoc%2flatest%2fdevel%2fporting.html%23&umid=60097eda
>> -f136-45a1-9c8e-
>> cf6a76e45cf8&auth=860a7ebb9feba264acc79b6e38eb59582349362c-
>> 480ae23736add41c88ab8d30c090a75517ca7f9e but couldn't follow the
>> instructions.
>>> I would like to port barebox to a new SoC (which is not a derivative of any
>> known SoC).
>>> It has the following:
>>> * Single Cortex A53
>>> * SRAM (4MB) located on address 0xC000000000
>>>
>>> The below patch shows my initial test to try and have a starting point.
>>> I am setting env variables:
>>> export ARCH=arm64
>>> export CROSS_COMPILE=/home/pliops/workspace/ARM/arm-gnu-
>> toolchain/bin/aarch64-none-elf-
>>>
>>> Then I build with:
>>> make spider_defconfig && make
>>>
>>> This gives an error:
>>> aarch64-none-elf-gcc: error: unrecognized argument in option '-mabi=apcs-
>> gnu'
>>> aarch64-none-elf-gcc: note: valid arguments to '-mabi=' are: ilp32 lp64
>>> aarch64-none-elf-gcc: error: unrecognized command-line option '-msoft-
>> float'
>>> aarch64-none-elf-gcc: error: unrecognized command-line option '-mno-
>> unaligned-access'
>>> /home/pliops/workspace/simplest-linux-
>> demo/barebox/scripts/Makefile.build:140: recipe for target
>> 'scripts/mod/empty.o' failed
>>> make[2]: *** [scripts/mod/empty.o] Error 1
>>>
>>> Not sure why the compiler flags get -mabi=apcs-gnu when I explicitly set
>> CONFIG_CPU_V8 and the arch/arm/Makefile has:
>>> ifeq ($(CONFIG_CPU_V8), y)
>>> CFLAGS_ABI      :=-mabi=lp64
>>>
>>> The changes I did:
>>> >From 848b5f9b18bb1bb96d197cbc1b368ee0a729d581 Mon Sep 17
>> 00:00:00 2001
>>> ---
>>>  arch/arm/Kconfig                      | 13 ++++++++
>>>  arch/arm/Makefile                     |  1 +
>>>  arch/arm/boards/Makefile              |  1 +
>>>  arch/arm/boards/spider-evk/Makefile   |  4 +++
>>>  arch/arm/boards/spider-evk/board.c    | 26 +++++++++++++++
>>>  arch/arm/boards/spider-evk/lowlevel.c | 30 +++++++++++++++++
>>>  arch/arm/configs/spider_defconfig     |  8 +++++
>>>  arch/arm/dts/Makefile                 |  1 +
>>>  arch/arm/dts/spider-mk1-evk.dts       | 10 ++++++
>>>  arch/arm/dts/spider-mk1.dtsi          | 46 +++++++++++++++++++++++++++
>>>  arch/arm/mach-spider/Kconfig          | 16 ++++++++++
>>>  arch/arm/mach-spider/Makefile         |  1 +
>>>  arch/arm/mach-spider/lowlevel.c       | 14 ++++++++
>>>  images/Makefile                       |  1 +
>>>  images/Makefile.spider                |  5 +++
>>>  include/mach/spider/lowlevel.h        |  7 ++++
>>>  16 files changed, 184 insertions(+)
>>>  create mode 100644 arch/arm/boards/spider-evk/Makefile
>>>  create mode 100644 arch/arm/boards/spider-evk/board.c
>>>  create mode 100644 arch/arm/boards/spider-evk/lowlevel.c
>>>  create mode 100644 arch/arm/configs/spider_defconfig  create mode
>> 100644 arch/arm/dts/spider-mk1-evk.dts  create mode 100644
>> arch/arm/dts/spider-mk1.dtsi  create mode 100644 arch/arm/mach-
>> spider/Kconfig  create mode 100644 arch/arm/mach-spider/Makefile  create
>> mode 100644 arch/arm/mach-spider/lowlevel.c  create mode 100644
>> images/Makefile.spider  create mode 100644 include/mach/spider/lowlevel.h
>>>
>>> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index
>> e76ee0f6dfe1..e5dcf128447e 100644
>>> --- a/arch/arm/Kconfig
>>> +++ b/arch/arm/Kconfig
>>> @@ -255,6 +255,18 @@ config ARCH_ROCKCHIP
>>>         select HAS_DEBUG_LL
>>>         imply GPIO_ROCKCHIP
>>>
>>> +config ARCH_SPIDER
>>> +       bool "Pliops Spider based"
>>> +       depends on 64BIT
>>> +       depends on ARCH_MULTIARCH
>>> +       select GPIOLIB
>>> +       select HAVE_PBL_MULTI_IMAGES
>>> +       select COMMON_CLK
>>> +       select CLKDEV_LOOKUP
>>> +       select COMMON_CLK_OF_PROVIDER
>>> +       select OFTREE
>>> +       select OFDEVICE
>>> +
>>>  config ARCH_STM32MP
>>>         bool "STMicroelectronics STM32MP"
>>>         depends on 32BIT
>>> @@ -331,6 +343,7 @@ source "arch/arm/mach-omap/Kconfig"
>>>  source "arch/arm/mach-pxa/Kconfig"
>>>  source "arch/arm/mach-rockchip/Kconfig"
>>>  source "arch/arm/mach-socfpga/Kconfig"
>>> +source "arch/arm/mach-spider/Kconfig"
>>>  source "arch/arm/mach-stm32mp/Kconfig"
>>>  source "arch/arm/mach-versatile/Kconfig"
>>>  source "arch/arm/mach-vexpress/Kconfig"
>>> diff --git a/arch/arm/Makefile b/arch/arm/Makefile index
>> 35ebc70f44e2..4c63dfee48f4 100644
>>> --- a/arch/arm/Makefile
>>> +++ b/arch/arm/Makefile
>>> @@ -101,6 +101,7 @@ machine-$(CONFIG_ARCH_MXS)          += mxs
>>>  machine-$(CONFIG_ARCH_MVEBU)           += mvebu
>>>  machine-$(CONFIG_ARCH_NOMADIK)         += nomadik
>>>  machine-$(CONFIG_ARCH_OMAP)            += omap
>>> +machine-$(CONFIG_ARCH_SPIDER)          += spider
>>>  machine-$(CONFIG_ARCH_PXA)             += pxa
>>>  machine-$(CONFIG_ARCH_ROCKCHIP)                += rockchip
>>>  machine-$(CONFIG_ARCH_SAMSUNG)         += samsung
>>> diff --git a/arch/arm/boards/Makefile b/arch/arm/boards/Makefile index
>> 2877debad535..6fe0a90c81ea 100644
>>> --- a/arch/arm/boards/Makefile
>>> +++ b/arch/arm/boards/Makefile
>>> @@ -135,6 +135,7 @@ obj-
>> $(CONFIG_MACH_SOCFPGA_TERASIC_DE10_NANO)        += terasic-de10-
>> nano/
>>>  obj-$(CONFIG_MACH_SOCFPGA_TERASIC_SOCKIT)      += terasic-sockit/
>>>  obj-$(CONFIG_MACH_SOLIDRUN_CUBOX)              += solidrun-cubox/
>>>  obj-$(CONFIG_MACH_SOLIDRUN_MICROSOM)           += solidrun-
>> microsom/
>>> +obj-$(CONFIG_MACH_SPIDER_MK1_EVK)              += spider-evk/
>>>  obj-$(CONFIG_MACH_STM32MP15XX_DKX)             += stm32mp15xx-dkx/
>>>  obj-$(CONFIG_MACH_STM32MP13XX_DK)              += stm32mp13xx-dk/
>>>  obj-$(CONFIG_MACH_LXA_MC1)                     += lxa-mc1/
>>> diff --git a/arch/arm/boards/spider-evk/Makefile
>> b/arch/arm/boards/spider-evk/Makefile
>>> new file mode 100644
>>> index 000000000000..da63d2625f7a
>>> --- /dev/null
>>> +++ b/arch/arm/boards/spider-evk/Makefile
>>> @@ -0,0 +1,4 @@
>>> +# SPDX-License-Identifier: GPL-2.0-only
>>> +
>>> +obj-y += board.o
>>> +lwl-y += lowlevel.o
>>> diff --git a/arch/arm/boards/spider-evk/board.c b/arch/arm/boards/spider-
>> evk/board.c
>>> new file mode 100644
>>> index 000000000000..3920e83b457d
>>> --- /dev/null
>>> +++ b/arch/arm/boards/spider-evk/board.c
>>> @@ -0,0 +1,26 @@
>>> +#include <bbu.h>
>>> +#include <boot.h>
>>> +#include <bootm.h>
>>> +#include <common.h>
>>> +#include <deep-probe.h>
>>> +#include <environment.h>
>>> +#include <fcntl.h>
>>> +#include <globalvar.h>
>>> +
>>> +static int spider_board_probe(struct device *dev) {
>>> +      /* Do some board-specific setup */
>>> +      return 0;
>>> +}
>>> +
>>> +static const struct of_device_id spider_board_of_match[] = {
>>> +      { .compatible = "pliops,spider-mk1-evk" },
>>> +      { /* sentinel */ },
>>> +};
>>> +
>>> +static struct driver spider_board_driver = {
>>> +      .name = "board-spider",
>>> +      .probe = spider_board_probe,
>>> +      .of_compatible = spider_board_of_match, };
>>> +device_platform_driver(spider_board_driver);
>>> diff --git a/arch/arm/boards/spider-evk/lowlevel.c
>> b/arch/arm/boards/spider-evk/lowlevel.c
>>> new file mode 100644
>>> index 000000000000..e36fcde4208e
>>> --- /dev/null
>>> +++ b/arch/arm/boards/spider-evk/lowlevel.c
>>> @@ -0,0 +1,30 @@
>>> +#include <common.h>
>>> +#include <asm/barebox-arm.h>
>>> +#include <mach/spider/lowlevel.h>
>>> +
>>> +#define BASE_ADDR       (0xD000307000)
>>> +#define GPRAM_ADDR      (0xC000000000)
>>> +#define MY_STACK_TOP    (0xC000000000 + SZ_2M) // Set the stack 2MB
>> from GPRAM start (excatly in the middle)
>>> +static inline void spider_serial_putc(void *base, int c) {
>>> +//     if (!(readl(base + UCR1) & UCR1_UARTEN))
>>> +//             return;
>>> +//
>>> +//     while (!(readl(base + USR2) & USR2_TXDC));
>>> +//
>>> +//     writel(c, base + URTX0);
>>> +}
>>> +
>>> +ENTRY_FUNCTION_WITHSTACK(start_spider_mk1_evk, MY_STACK_TOP,
>> r0, r1,
>>> +r2) {
>>> +       extern char __dtb_spider_mk1_evk_start[];
>>> +
>>> +       spider_lowlevel_init();
>>> +
>>> +       relocate_to_current_adr();
>>> +       setup_c();
>>> +
>>> +       pbl_set_putc(spider_serial_putc, (void *)BASE_ADDR);
>>> +
>>> +       barebox_arm_entry(GPRAM_ADDR, SZ_2M,
>>> +__dtb_spider_mk1_evk_start); }
>>> diff --git a/arch/arm/configs/spider_defconfig
>> b/arch/arm/configs/spider_defconfig
>>> new file mode 100644
>>> index 000000000000..c91bb889d97f
>>> --- /dev/null
>>> +++ b/arch/arm/configs/spider_defconfig
>>> @@ -0,0 +1,8 @@
>>> +CONFIG_ARCH_SPIDER=y
>>> +CONFIG_MACH_SPIDER_MK1_EVK=y
>>> +CONFIG_BOARD_ARM_GENERIC_DT=y
>>> +CONFIG_MALLOC_TLSF=y
>>> +CONFIG_KALLSYMS=y
>>> +CONFIG_RELOCATABLE=y
>>> +CONFIG_CONSOLE_ALLOW_COLOR=y
>>> +CONFIG_PBL_CONSOLE=y
>>> diff --git a/arch/arm/dts/Makefile b/arch/arm/dts/Makefile index
>> 98f4c4e0194b..94b304d4878f 100644
>>> --- a/arch/arm/dts/Makefile
>>> +++ b/arch/arm/dts/Makefile
>>> @@ -134,6 +134,7 @@ lwl-$(CONFIG_MACH_SOLIDRUN_CUBOX) += dove-
>> cubox-bb.dtb.o
>>>  lwl-$(CONFIG_MACH_SOLIDRUN_MICROSOM) += imx6dl-
>> hummingboard.dtb.o imx6q-hummingboard.dtb.o \
>>>                                 imx6dl-hummingboard2.dtb.o imx6q-
>> hummingboard2.dtb.o \
>>>                                 imx6q-h100.dtb.o
>>> +lwl-$(CONFIG_MACH_SPIDER_MK1_EVK) += spider-mk1-evk.dtb.o
>>>  lwl-$(CONFIG_MACH_SKOV_IMX6) += imx6s-skov-imx6.dtb.o imx6dl-skov-
>> imx6.dtb.o imx6q-skov-imx6.dtb.o
>>>  lwl-$(CONFIG_MACH_SKOV_ARM9CPU) += at91-skov-arm9cpu.dtb.o
>>>  lwl-$(CONFIG_MACH_SEEED_ODYSSEY) += stm32mp157c-odyssey.dtb.o
>> diff --git a/arch/arm/dts/spider-mk1-evk.dts b/arch/arm/dts/spider-mk1-
>> evk.dts new file mode 100644 index 000000000000..b8081cb85bf8
>>> --- /dev/null
>>> +++ b/arch/arm/dts/spider-mk1-evk.dts
>>> @@ -0,0 +1,10 @@
>>> +// SPDX-License-Identifier: GPL-2.0 OR X11
>>> +
>>> +/dts-v1/;
>>> +
>>> +#include "spider-mk1.dtsi"
>>> +
>>> +/ {
>>> +       model = "Pliops Spider MK-I EVK";
>>> +       compatible = "pliops,spider-mk1-evk"; };
>>> diff --git a/arch/arm/dts/spider-mk1.dtsi b/arch/arm/dts/spider-mk1.dtsi
>> new file mode 100644 index 000000000000..d4613848169d
>>> --- /dev/null
>>> +++ b/arch/arm/dts/spider-mk1.dtsi
>>> @@ -0,0 +1,46 @@
>>> +// SPDX-License-Identifier: GPL-2.0 OR X11
>>> +
>>> +/ {
>>> +       #address-cells = <2>;
>>> +       #size-cells = <2>;
>>> +
>>> +       chosen {
>>> +               stdout-path = &uart0;
>>> +       };
>>> +
>>> +       aliases {
>>> +               serial0 = &uart0;
>>> +       };
>>> +
>>> +       cpus {
>>> +               #address-cells = <1>;
>>> +               #size-cells = <0>;
>>> +
>>> +               cpu0: cpu@0 {
>>> +                       device_type = "cpu";
>>> +                       compatible = "arm,cortex-a53";
>>> +                       reg = <0x0>;
>>> +               };
>>> +       };
>>> +
>>> +       memory@1000000 {
>>> +               reg = <0x0 0x1000000 0x0 0x400000>; /* 128M */
>>> +               device_type = "memory";
>>> +       };
>>> +
>>> +       soc {
>>> +               #address-cells = <2>;
>>> +               #size-cells = <2>;
>>> +               ranges;
>>> +
>>> +               sram@c000000000 {
>>> +                       compatible = "mmio-sram";
>>> +                       reg = <0xc0 0x0 0x0 0x400000>;
>>> +               };
>>> +
>>> +               uart0: serial@d000307000 {
>>> +                       compatible = "pliops,spider-uart";
>>> +                       reg = <0xd0 0x307000 0 0x1000>;
>>> +               };
>>> +       };
>>> +};
>>> diff --git a/arch/arm/mach-spider/Kconfig b/arch/arm/mach-spider/Kconfig
>> new file mode 100644 index 000000000000..6d2f888a5fd8
>>> --- /dev/null
>>> +++ b/arch/arm/mach-spider/Kconfig
>>> @@ -0,0 +1,16 @@
>>> +# SPDX-License-Identifier: GPL-2.0-only
>>> +
>>> +if ARCH_SPIDER
>>> +
>>> +config ARCH_SPIDER_MK1
>>> +       bool
>>> +       select CPU_V8
>>> +       help
>>> +         The first Cortex-A53-based SoC of the spider family.
>>> +         This symbol is invisble and select by boards
>>> +
>>> +config MACH_SPIDER_MK1_EVK
>>> +       bool "Pliops Spider Reference Design Board"
>>> +       select ARCH_SPIDER_MK1
>>> +
>>> +endif
>>> diff --git a/arch/arm/mach-spider/Makefile b/arch/arm/mach-
>> spider/Makefile new file mode 100644 index 000000000000..b08c4a93ca27
>>> --- /dev/null
>>> +++ b/arch/arm/mach-spider/Makefile
>>> @@ -0,0 +1 @@
>>> +lwl-y += lowlevel.o
>>> diff --git a/arch/arm/mach-spider/lowlevel.c b/arch/arm/mach-
>> spider/lowlevel.c new file mode 100644 index
>> 000000000000..5d62ef0f39e5
>>> --- /dev/null
>>> +++ b/arch/arm/mach-spider/lowlevel.c
>>> @@ -0,0 +1,14 @@
>>> +// SPDX-License-Identifier:     GPL-2.0+
>>> +
>>> +#include <linux/types.h>
>>> +#include <mach/spider/lowlevel.h>
>>> +#include <asm/barebox-arm-head.h>
>>> +
>>> +void spider_lowlevel_init(void)
>>> +{
>>> +       arm_cpu_lowlevel_init();
>>> +       /*
>>> +        * not yet relocated, only do writel/readl for stuff that's
>>> +        * critical to run early. No global variables allowed.
>>> +        */
>>> +}
>>> diff --git a/images/Makefile b/images/Makefile index
>> c93f9e268978..97521e713228 100644
>>> --- a/images/Makefile
>>> +++ b/images/Makefile
>>> @@ -150,6 +150,7 @@ include $(srctree)/images/Makefile.mxs  include
>> $(srctree)/images/Makefile.omap3  include
>> $(srctree)/images/Makefile.rockchip
>>>  include $(srctree)/images/Makefile.socfpga
>>> +include $(srctree)/images/Makefile.spider
>>>  include $(srctree)/images/Makefile.stm32mp
>>>  include $(srctree)/images/Makefile.tegra  include
>> $(srctree)/images/Makefile.versatile
>>> diff --git a/images/Makefile.spider b/images/Makefile.spider new file mode
>> 100644 index 000000000000..c32f2762df04
>>> --- /dev/null
>>> +++ b/images/Makefile.spider
>>> @@ -0,0 +1,5 @@
>>> +# SPDX-License-Identifier: GPL-2.0-only
>>> +
>>> +pblb-$(CONFIG_MACH_SPIDER_MK1_EVK) += start_spider_mk1_evk
>>> +FILE_barebox-spider-mk1-evk.img = start_spider_mk1_evk.pblb
>>> +image-$(CONFIG_MACH_SPIDER_MK1_EVK) += barebox-spider-mk1-
>> evk.img
>>> diff --git a/include/mach/spider/lowlevel.h
>> b/include/mach/spider/lowlevel.h new file mode 100644 index
>> 000000000000..6e0ce1c77f7e
>>> --- /dev/null
>>> +++ b/include/mach/spider/lowlevel.h
>>> @@ -0,0 +1,7 @@
>>> +/* SPDX-License-Identifier: GPL-2.0+ */ #ifndef __MACH_SPIDER_H_
>>> +#define __MACH_SPIDER_H_
>>> +
>>> +void spider_lowlevel_init(void);
>>> +
>>> +#endif
>>> --
>>> 2.38.4
>>>
>>>
>>
>> --
>> Pengutronix e.K.                           |                             |
>> Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
>> 31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
>> Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |
> 

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |