2017-11-08 17:53 GMT+08:00 Arnd Bergmann [off-list ref]:

On Wed, Nov 8, 2017 at 6:55 AM, Greentime Hu [off-list ref] wrote:

quoted

From: Greentime Hu <redacted>

Signed-off-by: Vincent Chen <redacted>
Signed-off-by: Greentime Hu <redacted>
---
 arch/nds32/boot/dts/Makefile   |    8 ++++++
 arch/nds32/boot/dts/ae3xx.dts  |   55 ++++++++++++++++++++++++++++++++++++
 arch/nds32/boot/dts/ag101p.dts |   60 ++++++++++++++++++++++++++++++++++++++++
 arch/nds32/kernel/devtree.c    |   45 ++++++++++++++++++++++++++++++
 4 files changed, 168 insertions(+)
 create mode 100644 arch/nds32/boot/dts/Makefile
 create mode 100644 arch/nds32/boot/dts/ae3xx.dts
 create mode 100644 arch/nds32/boot/dts/ag101p.dts
 create mode 100644 arch/nds32/kernel/devtree.c

diff --git a/arch/nds32/boot/dts/Makefile b/arch/nds32/boot/dts/Makefile
new file mode 100644
index 0000000..d31faa8
--- /dev/null
+++ b/arch/nds32/boot/dts/Makefile

@@ -0,0 +1,8 @@
+ifneq '$(CONFIG_NDS32_BUILTIN_DTB)' '""'
+BUILTIN_DTB := $(patsubst "%",%,$(CONFIG_NDS32_BUILTIN_DTB)).dtb.o
+else
+BUILTIN_DTB :=
+endif
+obj-$(CONFIG_OF) += $(BUILTIN_DTB)

For new architectures, I think it's better to not support built-in dtb
but instead require the
boot loader to be aware of device trees.

Thanks.
I got your point and we have uboot supporting DTB too.
But we use gdb to load vmlinux without uboot sometimes, it can help us
to verify kernel more easily.
If dtb pointer is set by uboot, we will use it instead of using built-in dtb.

quoted

+clean-files := *.dtb *.dtb.S

diff --git a/arch/nds32/boot/dts/ae3xx.dts b/arch/nds32/boot/dts/ae3xx.dts
new file mode 100644
index 0000000..b6c85dc
--- /dev/null
+++ b/arch/nds32/boot/dts/ae3xx.dts

@@ -0,0 +1,55 @@
+/dts-v1/;
+/ {
+       compatible = "nds32 ae3xx";

ae3xx looks like a wildcard name for multiple boards. Please always
have compatible
names without wildcards. You usually also want to list both the SoC
and the board
here.

Thanks.
It looks a little bit weird but its not a wildcards. :p
I will list all the names instead of wildcards if I need to add more platforms.

quoted

+       #address-cells = <1>;
+       #size-cells = <1>;
+       interrupt-parent = <&intc>;
+
+       chosen {
+               bootargs = "console=ttyS0,38400n8 earlyprintk=uart8250-32bit,0xf0300000 debug loglevel=7";
+       };

Remove the earlyprintk option from the bootargs here, regular boards
should never rely
on earlyprintk. The "earlycon" support in the uart drivers works
almost as well (it starts
slightly later in the boot process), and it will pick up the uart from
the chosen/stdout-path
property.

Thanks.
I will remove it.

quoted

+       if (!params || !early_init_dt_scan(params)) {
+               pr_crit("\n"
+                       "Error: invalid device tree blob at (virtual address 0x%p)\n"
+                       "The dtb must be 8-byte aligned and must not exceed 8 KB in size\n"
+                       "\nPlease check your bootloader.", params);

What is the 8KB limit for the dtb for? This sounds really limiting
once you get to
more complex SoCs.

Thanks.
We allow uboot to set its start address and we think it might not be
too big thus we limit it to 8KB.
Maybe I should use a big size for complex SoCs.
I will update it in the next version patch.