Thx for the clarification.

On Mon, Jun 7, 2021 at 3:27 PM Maxime Ripard [off-list ref] wrote:

On Mon, Jun 07, 2021 at 11:44:03AM +0800, Guo Ren wrote:

quoted

On Mon, Jun 7, 2021 at 12:26 AM Jernej Škrabec [off-list ref] wrote:

quoted

Hi!

I didn't go through all details. After you fix all comments below, you should
run "make dtbs_check" and fix all reported warnings too.

Dne nedelja, 06. junij 2021 ob 11:04:07 CEST je guoren@kernel.org napisal(a):

quoted

From: Guo Ren <redacted>

Add initial DTS for Allwinner D1 NeZha board having only essential
devices (uart, dummy, clock, reset, clint, plic, etc).

Signed-off-by: Guo Ren <redacted>
Co-Developed-by: Liu Shaohua <redacted>
Signed-off-by: Liu Shaohua <redacted>
Cc: Anup Patel <redacted>
Cc: Atish Patra <redacted>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chen-Yu Tsai <redacted>
Cc: Drew Fustini <redacted>
Cc: Maxime Ripard <redacted>
Cc: Palmer Dabbelt <redacted>
Cc: Wei Fu <wefu@redhat.com>
Cc: Wei Wu <redacted>
---
 arch/riscv/boot/dts/Makefile                       |  1 +
 arch/riscv/boot/dts/allwinner/Makefile             |  2 +
 .../boot/dts/allwinner/allwinner-d1-nezha-kit.dts  | 29 ++++++++
 arch/riscv/boot/dts/allwinner/allwinner-d1.dtsi    | 84
++++++++++++++++++++++ 4 files changed, 116 insertions(+)
 create mode 100644 arch/riscv/boot/dts/allwinner/Makefile
 create mode 100644 arch/riscv/boot/dts/allwinner/allwinner-d1-nezha-kit.dts
create mode 100644 arch/riscv/boot/dts/allwinner/allwinner-d1.dtsi

diff --git a/arch/riscv/boot/dts/Makefile b/arch/riscv/boot/dts/Makefile
index fe996b8..3e7b264 100644
--- a/arch/riscv/boot/dts/Makefile
+++ b/arch/riscv/boot/dts/Makefile

@@ -2,5 +2,6 @@
 subdir-y += sifive
 subdir-$(CONFIG_SOC_CANAAN_K210_DTB_BUILTIN) += canaan
 subdir-y += microchip
+subdir-y += allwinner

 obj-$(CONFIG_BUILTIN_DTB) := $(addsuffix /, $(subdir-y))

diff --git a/arch/riscv/boot/dts/allwinner/Makefile

b/arch/riscv/boot/dts/allwinner/Makefile new file mode 100644
index 00000000..4adbf4b

--- /dev/null
+++ b/arch/riscv/boot/dts/allwinner/Makefile

@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0
+dtb-$(CONFIG_SOC_SUNXI) += allwinner-d1-nezha-kit.dtb

diff --git a/arch/riscv/boot/dts/allwinner/allwinner-d1-nezha-kit.dts

b/arch/riscv/boot/dts/allwinner/allwinner-d1-nezha-kit.dts new file mode
100644
index 00000000..cd9f7c9

--- /dev/null
+++ b/arch/riscv/boot/dts/allwinner/allwinner-d1-nezha-kit.dts

Board DT names are comprised of soc name and board name, in this case it would
be "sun20i-d1-nezha-kit.dts"

quoted

@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)

Usually copyrights are added below spdx id.

quoted

+
+/dts-v1/;
+
+#include "allwinner-d1.dtsi"
+
+/ {
+     #address-cells = <2>;
+     #size-cells = <2>;

This should be part of SoC level DTSI.

quoted

+     model = "Allwinner D1 NeZha Kit";
+     compatible = "allwinner,d1-nezha-kit";

Board specific compatible string should be followed with SoC compatible, in
this case "allwinner,sun20i-d1".  You should document it too.

quoted

+
+     chosen {
+             bootargs = "console=ttyS0,115200";

Above line doesn't belong here. If anything, it should be added dynamically by
bootloader.

After discussion, we still want to keep a default value here.
Sometimes we could boot with jtag and parse dtb is hard for gdbinit
script.

quoted

quoted

+             stdout-path = &serial0;
+     };
+
+     memory@40000000 {
+             device_type = "memory";
+             reg = <0x0 0x40000000 0x0 0x20000000>;
+     };

Ditto for whole memory node.

Ditto

The thing is that there's never a good value for a default. Let's take
the memory node here: what would be a good default? If we want to make
it work everywhere it's going to be the lowest amount of memory
available on the D1 boards. It's going to be hard to maintain and very
likely to be overlooked, resulting in broken boards anyway.

If someone is savvy enough to use JTAG, it's not really difficult to
modify the DT for their board when they need it.

okay, I see. I'll follow the rule in the next version of the patchset.

Maxime

-- 
Best Regards
 Guo Ren

ML: https://lore.kernel.org/linux-csky/