On 2020/5/18 09:08, Tiezhu Yang wrote:
On 05/16/2020 07:09 PM, WANG Xuerui wrote:
On 5/16/20 3:03 PM, Tiezhu Yang wrote:
After commit 87fcfa7b7fe6 ("MIPS: Loongson64: Add generic dts"),
there already exists the node and property of Loongson CPU UART0
in loongson3-package.dtsi:
cpu_uart0: serial@1fe001e0 {
compatible = "ns16550a";
reg = <0 0x1fe001e0 0x8>;
clock-frequency = <33000000>;
interrupt-parent = <&liointc>;
interrupts = <10 IRQ_TYPE_LEVEL_HIGH>;
no-loopback-test;
};
In order to support for serial console on the Loongson platform,
add CONFIG_SERIAL_OF_PLATFORM=y to loongson3_defconfig.
With this patch, we can see the following boot message:
[ 1.877745] printk: console [ttyS0] disabled
[ 1.881979] 1fe001e0.serial: ttyS0 at MMIO 0x1fe001e0 (irq = 16,
base_baud = 2062500) is a 16550A
[ 1.890838] printk: console [ttyS0] enabled
And also, we can login normally from the serial console.
Signed-off-by: Tiezhu Yang <yangtie...@loongson.cn>
---
Hi Jiaxun,
Thank you very much for your suggestion.
arch/mips/configs/loongson3_defconfig | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/mips/configs/loongson3_defconfig
b/arch/mips/configs/loongson3_defconfig
index 6768c16..cd95f08 100644
--- a/arch/mips/configs/loongson3_defconfig
+++ b/arch/mips/configs/loongson3_defconfig
@@ -217,6 +217,7 @@ CONFIG_SERIAL_8250_EXTENDED=y
CONFIG_SERIAL_8250_MANY_PORTS=y
CONFIG_SERIAL_8250_SHARE_IRQ=y
CONFIG_SERIAL_8250_RSA=y
+CONFIG_SERIAL_OF_PLATFORM=y
CONFIG_HW_RANDOM=y
CONFIG_RAW_DRIVER=m
CONFIG_I2C_CHARDEV=y
Hi,
The patch title is again exaggerating things. This is a defconfig
change, so please refer to `git log` output of `arch/mips/configs`
and use something like "MIPS: Loongson: loongson3_defconfig: enable
serial console" or "MIPS: Loongson: enable serial console in
defconfig". The current title reads as if Loongson kernels never were
able to use a serial console in the past.
Hi Xuerui,
Thanks for your suggestion.
We can not use the serial console without this patch,
so I use the current patch subject.
One can always use their own config to build in whatever support they
want. Only people blindly following defconfig are affected. That's why I
think the original patch title is exaggerating.
Anyway, let me modify the patch subject to make it more accurate,
I think the following is better:
"MIPS: Loongson: Enable devicetree based probing for 8250 ports"
drivers/tty/serial/8250/Kconfig:
config SERIAL_OF_PLATFORM
tristate "Devicetree based probing for 8250 ports"
I will send v2 later.
No problem. Just make it clear that these are defconfig changes so
people don't misunderstand, even if they're otherwise unfamiliar with
the current state of things.
Thanks,
Tiezhu Yang
