[RFC PATCH v2] mips: dts: add initial support for ls1c300 SoC

Sean Anderson seanga2 at gmail.com
Wed Apr 6 20:06:56 CEST 2022


Hi Du,

Some of my comments on your previous patch still apply. This should be
broken up into separate commits for submission.

On 4/5/22 5:12 PM, Du Huanpeng wrote:
> Loongson 1C is a cost-effective SOC chip for industrial control and
> the Internet of Things. The Loongson 1C includes a floating-point
> processing unit, supports multiple types of memory, and supports
> high-capacity MLC NAND Flash. Loongson 1C provides developers with a
> wealth of peripheral interfaces and on-chip modules, including Camera
> controller, USB OTG and USB HOST interfaces, AC97/I2S controller, LCD
> controller, SPI interface, UART interface, etc., providing sufficient
> computing power and multi-application connectivity.
> 
> Some highlights of this SoC are:
> - Single core LS232, MIPS32 instruction set compatible, main frequency
> 300MHZ
> - 16KB data cache and 16KB instruction cache
> - 64 bit float unit, hardware division
> - 8/16 bit SDRAM controller, 45 ~ 133MHz
> - 8/16 bit SRAM, NAND
> - I2S/AC97, LCD, MAC, USB, OTG, SPI, I2C, PWM, CAN, SDIO, ADC
> - 12 UARTs
> 
> See Techinical Reference Manual for details: https://www.loongson.cn/

nit: Technical

> introduce base support for the ls1c300 SoC.
> - debug UART2
> - serial console
> - clock
> - watchdog
> - sysreset
> - many uarts

Please mention the boot process here. In particular, XIP is unusual
for new SoCs, so it should definitely be mentioned.

> Signed-off-by: Du Huanpeng <dhu at hodcarrier.org>
> 
> ---
> Changelog for v2:
> 1. dtsi:
> 	add status disabled for uart0 ~ uart11
> 	remove bootargs from chosen
> 	make serial0 alias for uart2
> 	oscillator remove @0 unit-address
> 	change uart2 address to kuseg
> 
> 2. cleanup Kconfig and update defconfig
> - make these options configurable, disabled by default:
> 	CMD_DM
> 	DM_ETH
> 	DM_GPIO
> 	DM_SPI
> 	DM_SPI_FLASH
> 	DM_RESET
> 	PINCONF
> 	PINCTRL
> 	PINMUX
> 	RESET_LSMIPS
> - make these options configurable, enabled by default:
> 	CLK
> 	DISPLAY_CPUINFO
> 	SYSRESET
> 	ROM_EXCEPTION_VECTORS
> - disabled:
> 	CONFIG_ENV_IS_IN_SPI_FLASH
> 
> 3. fix codingstyle drivers/watchdog/lsmips-wdt.c
> - priv->base + offset
> - add comment for default clock value
> 
> 4. remove address base definition header
> - remove arch/mips/mach-lsmips/ls1c300/ls1c300.h
> - clean up files uses this header
> 
> 5. spl and debug uart
> - add comment for spl & debug uart pinmuxing
> - cleanup unused registers base header
> 
> 6.  dtsi
> - add "loongson,ls1c300-uart" to all uart node
> 
> 7. board dts
> - add memory node to board dts, start at 0x80000000, size 64MB
> 
> 8. Kconfig
> - make ROM_EXCEPTION_VECTORS user configureable
> - enable ROM_EXCEPTION_VECTORS in defconfig
> 
> 9.
> - seperate sdram_init to sdram_init.S
> - add macro helpers to do sdram, pll lowlevel init
> 
> 10. dtsi
> - move clock nodes to /clocks/xxx
> 
> 11.
> - define CONFIG_SKIP_LOWLEVEL_INIT to 1
> 
> 12.
> - remove option PINCTRL_LS1C300 from Kconfig
> 
> 13.
> - dram_init, use get_ram_size() to detect ram size.
> 
> 14. clk driver
> - create custom clock ops for PLL
> - remove debug code
> 
> 15.
> - rebase to 59bffec43a657598b194b9eb30dc01eec06078c7
> - remove CONFIG_SYS_MONITOR_BASE from include/configs/
> 
>> commit e4d741f8abc4a92426d3a826f99390c3abe02d61
>> Author: Tom Rini <trini at konsulko.com>
>> Date:   Thu Mar 24 17:18:05 2022 -0400
>>
>>      Convert CONFIG_SYS_MONITOR_BASE to Kconfig
> ---
>   MAINTAINERS                                   |  13 ++
>   arch/mips/Kconfig                             |  11 ++
>   arch/mips/Makefile                            |   1 +
>   arch/mips/dts/Makefile                        |   1 +
>   arch/mips/dts/loongson32-ls1c300b.dtsi        | 166 ++++++++++++++++++
>   arch/mips/dts/ls1c300-eval.dts                |  31 ++++
>   arch/mips/mach-lsmips/Kconfig                 |  76 ++++++++
>   arch/mips/mach-lsmips/Makefile                |   6 +
>   arch/mips/mach-lsmips/cpu.c                   |  19 ++
>   arch/mips/mach-lsmips/include/mach/serial.h   |  16 ++
>   arch/mips/mach-lsmips/ls1c300/Makefile        |   7 +
>   arch/mips/mach-lsmips/ls1c300/gpio.c          |  66 +++++++
>   arch/mips/mach-lsmips/ls1c300/init.c          |  59 +++++++
>   arch/mips/mach-lsmips/ls1c300/lowlevel_init.S | 136 ++++++++++++++
>   arch/mips/mach-lsmips/ls1c300/sdram.S         |  93 ++++++++++
>   arch/mips/mach-lsmips/ls1c300/serial.c        | 109 ++++++++++++
>   arch/mips/mach-lsmips/spl.c                   |  47 +++++
>   board/loongson/ls1c300-eval/Kconfig           |  12 ++
>   board/loongson/ls1c300-eval/MAINTAINERS       |   7 +
>   board/loongson/ls1c300-eval/Makefile          |   3 +
>   board/loongson/ls1c300-eval/board.c           |  20 +++
>   configs/ls1c300_defconfig                     |  54 ++++++
>   drivers/clk/Makefile                          |   1 +
>   drivers/clk/lsmips/Makefile                   |   3 +
>   drivers/clk/lsmips/clk-ls1c300.c              | 161 +++++++++++++++++
>   drivers/watchdog/Kconfig                      |   8 +
>   drivers/watchdog/Makefile                     |   1 +
>   drivers/watchdog/lsmips_wdt.c                 | 131 ++++++++++++++
>   include/configs/ls1c300.h                     |  59 +++++++
>   include/dt-bindings/clock/ls1c300-clk.h       |  48 +++++
>   30 files changed, 1365 insertions(+)
>   create mode 100644 arch/mips/dts/loongson32-ls1c300b.dtsi
>   create mode 100644 arch/mips/dts/ls1c300-eval.dts
>   create mode 100644 arch/mips/mach-lsmips/Kconfig
>   create mode 100644 arch/mips/mach-lsmips/Makefile
>   create mode 100644 arch/mips/mach-lsmips/cpu.c
>   create mode 100644 arch/mips/mach-lsmips/include/mach/serial.h
>   create mode 100644 arch/mips/mach-lsmips/ls1c300/Makefile
>   create mode 100644 arch/mips/mach-lsmips/ls1c300/gpio.c
>   create mode 100644 arch/mips/mach-lsmips/ls1c300/init.c
>   create mode 100644 arch/mips/mach-lsmips/ls1c300/lowlevel_init.S
>   create mode 100644 arch/mips/mach-lsmips/ls1c300/sdram.S
>   create mode 100644 arch/mips/mach-lsmips/ls1c300/serial.c
>   create mode 100644 arch/mips/mach-lsmips/spl.c
>   create mode 100644 board/loongson/ls1c300-eval/Kconfig
>   create mode 100644 board/loongson/ls1c300-eval/MAINTAINERS
>   create mode 100644 board/loongson/ls1c300-eval/Makefile
>   create mode 100644 board/loongson/ls1c300-eval/board.c
>   create mode 100644 configs/ls1c300_defconfig
>   create mode 100644 drivers/clk/lsmips/Makefile
>   create mode 100644 drivers/clk/lsmips/clk-ls1c300.c
>   create mode 100644 drivers/watchdog/lsmips_wdt.c
>   create mode 100644 include/configs/ls1c300.h
>   create mode 100644 include/dt-bindings/clock/ls1c300-clk.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 0fc034f01f..a6927fa4a5 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -954,6 +954,19 @@ F:	drivers/net/cortina_ni.c
>   F:	drivers/net/cortina_ni.h
>   F:	drivers/net/phy/ca_phy.c
>   
> +MIPS LOONGSON LS1C300
> +M:      Du Huanpeng <dhu at hodcarrier.org>
> +S:      Maintained
> +F:      arch/mips/dts/loongson32-ls1c300b.dtsi
> +F:      arch/mips/dts/ls1c300-eval.dts
> +F:      arch/mips/mach-lsmips/
> +F:      board/loongson/ls1c300-eval/
> +F:      configs/ls1c300_defconfig
> +F:      drivers/clk/lsmips/
> +F:      drivers/watchdog/lsmips_wdt.c
> +F:      include/configs/ls1c300.h
> +F:      include/dt-bindings/clock/ls1c300-clk.h
> +
>   MIPS MEDIATEK
>   M:	Weijie Gao <weijie.gao at mediatek.com>
>   R:	GSS_MTK_Uboot_upstream <GSS_MTK_Uboot_upstream at mediatek.com>
> diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
> index 06cae68ee5..461bb2a99b 100644
> --- a/arch/mips/Kconfig
> +++ b/arch/mips/Kconfig
> @@ -93,6 +93,16 @@ config ARCH_MTMIPS
>   	select SUPPORTS_LITTLE_ENDIAN
>   	select SUPPORT_SPL
>   
> +config ARCH_LSMIPS
> +	bool "Support Loongson MIPS platforms"
> +	select DM
> +	select DM_SERIAL
> +	select OF_CONTROL
> +	select SUPPORTS_CPU_MIPS32_R1
> +	select SUPPORTS_CPU_MIPS32_R2
> +	select SUPPORTS_LITTLE_ENDIAN
> +	select SUPPORT_SPL
> +
>   config ARCH_JZ47XX
>   	bool "Support Ingenic JZ47xx"
>   	select SUPPORT_SPL
> @@ -175,6 +185,7 @@ source "arch/mips/mach-bmips/Kconfig"
>   source "arch/mips/mach-jz47xx/Kconfig"
>   source "arch/mips/mach-pic32/Kconfig"
>   source "arch/mips/mach-mtmips/Kconfig"
> +source "arch/mips/mach-lsmips/Kconfig"
>   source "arch/mips/mach-octeon/Kconfig"
>   
>   if MIPS
> diff --git a/arch/mips/Makefile b/arch/mips/Makefile
> index 6502aebd29..e944502497 100644
> --- a/arch/mips/Makefile
> +++ b/arch/mips/Makefile
> @@ -16,6 +16,7 @@ machine-$(CONFIG_ARCH_BMIPS) += bmips
>   machine-$(CONFIG_ARCH_JZ47XX) += jz47xx
>   machine-$(CONFIG_MACH_PIC32) += pic32
>   machine-$(CONFIG_ARCH_MTMIPS) += mtmips
> +machine-$(CONFIG_ARCH_LSMIPS) += lsmips
>   machine-$(CONFIG_ARCH_MSCC) += mscc
>   machine-${CONFIG_ARCH_OCTEON} += octeon
>   
> diff --git a/arch/mips/dts/Makefile b/arch/mips/dts/Makefile
> index 95144b24dc..915acfd573 100644
> --- a/arch/mips/dts/Makefile
> +++ b/arch/mips/dts/Makefile
> @@ -19,6 +19,7 @@ dtb-$(CONFIG_BOARD_MT7620_MT7530_RFB) += mediatek,mt7620-mt7530-rfb.dtb
>   dtb-$(CONFIG_BOARD_MT7628_RFB) += mediatek,mt7628-rfb.dtb
>   dtb-$(CONFIG_BOARD_GARDENA_SMART_GATEWAY_MT7688) += gardena-smart-gateway-mt7688.dtb
>   dtb-$(CONFIG_BOARD_LINKIT_SMART_7688) += linkit-smart-7688.dtb
> +dtb-$(CONFIG_BOARD_LS1C300) += ls1c300-eval.dtb
>   dtb-$(CONFIG_TARGET_OCTEON_EBB7304) += mrvl,octeon-ebb7304.dtb
>   dtb-$(CONFIG_TARGET_OCTEON_NIC23) += mrvl,octeon-nic23.dtb
>   dtb-$(CONFIG_BOARD_NETGEAR_CG3100D) += netgear,cg3100d.dtb
> diff --git a/arch/mips/dts/loongson32-ls1c300b.dtsi b/arch/mips/dts/loongson32-ls1c300b.dtsi
> new file mode 100644
> index 0000000000..a47f1927cd
> --- /dev/null
> +++ b/arch/mips/dts/loongson32-ls1c300b.dtsi
> @@ -0,0 +1,166 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <dt-bindings/clock/ls1c300-clk.h>
> +
> +/ {
> +	#address-cells = <1>;
> +	#size-cells = <1>;
> +	compatible = "loongson,ls1c300-soc";
> +
> +	cpus {
> +		#address-cells = <1>;
> +		#size-cells = <0>;
> +		cpu at 0 {
> +			device_type = "cpu";
> +			reg = <0>;
> +			compatible = "loongson,gs232", "mips,mips4Kc";
> +			clocks = <&acc CLK_CPU>;
> +		};
> +	};
> +
> +	clocks {
> +		#address-cells = <1>;
> +		#size-cells = <1>;
> +		u-boot,dm-pre-reloc;
> +
> +		xtal: oscillator {
> +			compatible = "fixed-clock";
> +			clock-frequency = <24000000>;
> +			#clock-cells = <0>;
> +		};
> +
> +		acc: clock-controller at 1fe78030 {
> +			compatible = "loongson,ls1c300-clk";
> +			clocks = <&xtal>;
> +			#clock-cells = <1>;
> +			reg = <0x1fe78030 0x8>, <0x1fe7c010 0x4>;

The documented register values here start with 0xbfe7. Presumably
the top 3 bits are ignored? If that's the case, can you document it?

> +			u-boot,dm-pre-reloc;
> +		};

This goes under /soc since it is a real device.

> +	};
> +
> +	soc {
> +		#address-cells = <1>;
> +		#size-cells = <1>;
> +		compatible = "simple-bus";
> +		ranges;
> +
> +		uart0: serial at 1fe40000 {
> +			compatible = "loongson,ls1c300-uart", "ns16550a";
> +			clocks = <&acc CLK_UART0>;
> +			reg = <0x1fe40000 0x100>;
> +			reg-shift = <0>;

For the curious, the shift really is zero.

> +

No blank line necessary here.

> +			status = "disabled";
> +		};
> +
> +		uart1: serial at 1fe44000 {
> +			compatible = "loongson,ls1c300-uart", "ns16550a";
> +			clocks = <&acc CLK_UART1>;
> +			reg = <0x1fe44000 0x100>;
> +			reg-shift = <0>;
> +
> +			status = "disabled";
> +		};
> +
> +		uart2: serial at 1fe48000 {
> +			compatible = "loongson,ls1c300-uart", "ns16550a";
> +			clocks = <&acc CLK_UART2>;
> +			reg = <0x1fe48000 0x100>;
> +			reg-shift = <0>;
> +
> +			status = "disabled";
> +		};
> +
> +		uart3: serial at 1fe4c000 {
> +			compatible = "loongson,ls1c300-uart", "ns16550a";
> +			clocks = <&acc CLK_UART3>;
> +			reg = <0x1fe4c000 0x100>;
> +			reg-shift = <0>;
> +
> +			status = "disabled";
> +		};
> +
> +		uart4:  serial at 1fe4c400 {
> +			compatible = "loongson,ls1c300-uart", "ns16550a";
> +			clocks = <&acc CLK_UART4>;
> +			reg = <0x1fe4c400 0x100>;
> +			reg-shift = <0>;
> +
> +			status = "disabled";
> +		};
> +
> +		uart5:  serial at 1fe4c500 {
> +			compatible = "loongson,ls1c300-uart", "ns16550a";
> +			clocks = <&acc CLK_UART5>;
> +			reg = <0x1fe4c500 0x100>;
> +			reg-shift = <0>;
> +
> +			status = "disabled";
> +		};
> +
> +		uart6:  serial at 1fe4c600 {
> +			compatible = "loongson,ls1c300-uart", "ns16550a";
> +			clocks = <&acc CLK_UART6>;
> +			reg = <0x1fe4c600 0x100>;
> +			reg-shift = <0>;
> +
> +			status = "disabled";
> +		};
> +
> +		uart7:  serial at 1fe4c700 {
> +			compatible = "loongson,ls1c300-uart", "ns16550a";
> +			clocks = <&acc CLK_UART7>;
> +			reg = <0x1fe4c700 0x100>;
> +			reg-shift = <0>;
> +
> +			status = "disabled";
> +		};
> +
> +		uart8:  serial at 1fe4c800 {
> +			compatible = "loongson,ls1c300-uart", "ns16550a";
> +			clocks = <&acc CLK_UART8>;
> +			reg = <0x1fe4c800 0x100>;
> +			reg-shift = <0>;
> +
> +			status = "disabled";
> +		};
> +
> +		uart9:  serial at 1fe4c900 {
> +			compatible = "loongson,ls1c300-uart", "ns16550a";
> +			clocks = <&acc CLK_UART9>;
> +			reg = <0x1fe4c900 0x100>;
> +			reg-shift = <0>;
> +
> +			status = "disabled";
> +		};
> +
> +		uart10: serial at 1fe4ca00 {
> +			compatible = "loongson,ls1c300-uart", "ns16550a";
> +			clocks = <&acc CLK_UART10>;
> +			reg = <0x1fe4ca00 0x100>;
> +			reg-shift = <0>;
> +
> +			status = "disabled";
> +		};
> +
> +		uart11: serial at 1fe4cb00 {
> +			compatible = "loongson,ls1c300-uart", "ns16550a";
> +			clocks = <&acc CLK_UART11>;
> +			reg = <0x1fe4cb00 0x100>;
> +			reg-shift = <0>;
> +
> +			status = "disabled";
> +		};
> +
> +		wdt: watchdog at 1fe5c060 {
> +			compatible = "loongson,ls1c300-wdt";
> +			clocks = <&acc CLK_WDT>;
> +			reg = <0x1fe5c060 0x10>;
> +		};
> +
> +		reset-controller {
> +			compatible = "wdt-reboot";
> +			wdt = <&wdt>;
> +		};
> +
> +	};
> +};
> diff --git a/arch/mips/dts/ls1c300-eval.dts b/arch/mips/dts/ls1c300-eval.dts
> new file mode 100644
> index 0000000000..eaf65b2d96
> --- /dev/null
> +++ b/arch/mips/dts/ls1c300-eval.dts
> @@ -0,0 +1,31 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2022 Du Huanpeng <dhu at hodcarrier.org>
> + */
> +
> +/dts-v1/;
> +
> +#include "loongson32-ls1c300b.dtsi"
> +
> +/ {
> +	compatible = "lsmips,ls1c300-soc";
> +	model = "ls1c300-eval";
> +
> +	aliases {
> +		serial0 = &uart2;

Why not serial2?

> +	};
> +
> +	memory at 80000000 {
> +		device_type = "memory";
> +		reg = <0x80000000 0x4000000>;
> +	};
> +
> +	chosen {
> +		stdout-path = "serial0:115200n8";

Remove as requested.

> +	};
> +};
> +
> +&uart2 {
> +	status = "okay";
> +};
> +
> diff --git a/arch/mips/mach-lsmips/Kconfig b/arch/mips/mach-lsmips/Kconfig
> new file mode 100644
> index 0000000000..2e43a98bfb
> --- /dev/null
> +++ b/arch/mips/mach-lsmips/Kconfig
> @@ -0,0 +1,76 @@
> +menu "Loongson MIPS platforms"
> +	depends on ARCH_LSMIPS
> +
> +config SYS_MALLOC_F_LEN
> +	default 0x1000
> +
> +config SYS_SOC
> +	default "ls1c300" if SOC_LS1C300
> +
> +config SYS_DCACHE_SIZE
> +	default 16384
> +
> +config SYS_DCACHE_LINE_SIZE
> +	default 32
> +
> +config SYS_ICACHE_SIZE
> +	default 16384
> +
> +config SYS_ICACHE_LINE_SIZE
> +	default 32
> +
> +config SYS_TEXT_BASE
> +	default 0xbfc00000 if !SPL
> +	default 0x80200000 if SPL
> +
> +config SPL_TEXT_BASE
> +	default 0xbfc00000
> +
> +config SPL_PAYLOAD
> +	default "u-boot-lzma.img" if SPL_LZMA
> +
> +config BUILD_TARGET
> +	default "u-boot-with-spl.bin" if SPL
> +
> +choice
> +	prompt "Loongson MIPS SoC select"
> +
> +config SOC_LS1C300
> +	bool "LS1C300"
> +	select MIPS_L1_CACHE_SHIFT_5
> +	select CLK_CCF
> +	select SPL_SEPARATE_BSS if SPL
> +	select SPL_INIT_STACK_WITHOUT_MALLOC_F if SPL
> +	select SPL_LOADER_SUPPORT if SPL
> +	select SPL_OF_CONTROL if SPL_DM
> +	select SPL_SIMPLE_BUS if SPL_DM
> +	select SPL_DM_SERIAL if SPL_DM
> +	select SPL_CLK if SPL_DM && SPL_SERIAL
> +	select SPL_SYSRESET if SPL_DM
> +	select SPL_OF_LIBFDT if SPL_OF_CONTROL
> +	help
> +	  This supports Loongson LS1C300
> +
> +endchoice
> +
> +choice
> +	prompt "Board select"
> +
> +config BOARD_LS1C300
> +	bool "Loongson LS1C300 Eval"
> +	depends on SOC_LS1C300
> +	help
> +	  ls1c300-eval board has a LS1C300 SoC with 64MiB of SDRAM
> +	  and 512KiB of flash (SPI NOR) and additional NAND storage.
> +
> +endchoice
> +
> +config CONS_PIN
> +	int "pin group used in uart"
> +	default 0
> +	help
> +	  Select pin group connected to UART for your board.
> +
> +source "board/loongson/ls1c300-eval/Kconfig"
> +
> +endmenu
> diff --git a/arch/mips/mach-lsmips/Makefile b/arch/mips/mach-lsmips/Makefile
> new file mode 100644
> index 0000000000..654143a5f7
> --- /dev/null
> +++ b/arch/mips/mach-lsmips/Makefile
> @@ -0,0 +1,6 @@
> +# SPDX-License-Identifier: GPL-2.0+
> +
> +obj-y += cpu.o
> +obj-$(CONFIG_SPL_BUILD) += spl.o
> +
> +obj-$(CONFIG_SOC_LS1C300) += ls1c300/
> diff --git a/arch/mips/mach-lsmips/cpu.c b/arch/mips/mach-lsmips/cpu.c
> new file mode 100644
> index 0000000000..4205d8ef83
> --- /dev/null
> +++ b/arch/mips/mach-lsmips/cpu.c
> @@ -0,0 +1,19 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) 2018 Stefan Roese <sr at denx.de>
> + */
> +
> +#include <common.h>
> +#include <init.h>
> +#include <malloc.h>
> +#include <linux/bitops.h>
> +#include <linux/io.h>
> +#include <linux/sizes.h>
> +
> +DECLARE_GLOBAL_DATA_PTR;
> +
> +int dram_init(void)
> +{
> +	gd->ram_size = get_ram_size((void *)CONFIG_SYS_SDRAM_BASE, SZ_256M);
> +	return 0;
> +}
> diff --git a/arch/mips/mach-lsmips/include/mach/serial.h b/arch/mips/mach-lsmips/include/mach/serial.h
> new file mode 100644
> index 0000000000..4da1cb434c
> --- /dev/null
> +++ b/arch/mips/mach-lsmips/include/mach/serial.h
> @@ -0,0 +1,16 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2020 MediaTek Inc.
> + *
> + * Author:  Gao Weijie <weijie.gao at mediatek.com>
> + *
> + * Copyright (C) 2022 Du Huanpeng <dhu at hodcarrier.org>
> + */
> +
> +#ifndef __LSMIPS_SERIAL_H_
> +#define __LSMIPS_SERIAL_H_
> +
> +void lsmips_spl_serial_init(void);
> +int gpio_set_alternate(int gpio, int func);
> +
> +#endif /* __LSMIPS_SERIAL_H_ */
> diff --git a/arch/mips/mach-lsmips/ls1c300/Makefile b/arch/mips/mach-lsmips/ls1c300/Makefile
> new file mode 100644
> index 0000000000..17b9d6fb9c
> --- /dev/null
> +++ b/arch/mips/mach-lsmips/ls1c300/Makefile
> @@ -0,0 +1,7 @@
> +# SPDX-License-Identifier: GPL-2.0
> +
> +obj-y += lowlevel_init.o
> +obj-y += sdram.o
> +obj-y += init.o
> +obj-y += gpio.o
> +obj-$(CONFIG_SPL_BUILD) += serial.o
> diff --git a/arch/mips/mach-lsmips/ls1c300/gpio.c b/arch/mips/mach-lsmips/ls1c300/gpio.c
> new file mode 100644
> index 0000000000..2195738b2b
> --- /dev/null
> +++ b/arch/mips/mach-lsmips/ls1c300/gpio.c
> @@ -0,0 +1,66 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) 2022 Du Huanpeng <dhu at hodcarrier.org>
> + */
> +
> +#include <linux/errno.h>
> +#include <asm/bitops.h>
> +
> +#define CBUS_FIRST0	0xbfd011c0
> +#define CBUS_SECOND0	0xbfd011d0
> +#define CBUS_THIRD0	0xbfd011e0
> +#define CBUS_FOURTHT0	0xbfd011f0
> +#define CBUS_FIFTHT0	0xbfd01200
> +
> +#define CBUS_FIRST1	0xbfd011c4
> +#define CBUS_SECOND1	0xbfd011d4
> +#define CBUS_THIRD1	0xbfd011e4
> +#define CBUS_FOURTHT1	0xbfd011f4
> +#define CBUS_FIFTHT1	0xbfd01204
> +
> +#define CBUS_FIRST2	0xbfd011c8
> +#define CBUS_SECOND2	0xbfd011d8
> +#define CBUS_THIRD2	0xbfd011e8
> +#define CBUS_FOURTHT2	0xbfd011f8
> +#define CBUS_FIFTHT2	0xbfd01208
> +
> +#define CBUS_FIRST3	0xbfd011cc
> +#define CBUS_SECOND3	0xbfd011dc
> +#define CBUS_THIRD3	0xbfd011ec
> +#define CBUS_FOURTHT3	0xbfd011fc
> +#define CBUS_FIFTHT3	0xbfd0120c
> +
> +/*
> + * pinmux for debug uart and spl only, for others, please
> + * use a pinctrl driver and device-tree for pin muxing.
> + *
> + * @gpio: gpio number
> + * @func: alternate function 1 to 5, 0 for GPIO.
> + */
> +
> +int gpio_set_alternate(int gpio, int func)
> +{
> +	volatile void __iomem *addr;
> +	int i;
> +
> +	if (gpio < 0 || gpio > 104)
> +		return -ENODEV;
> +	if (func < 0 || func > 5)
> +		return -EINVAL;
> +
> +	if (func) {
> +		i = func - 1;
> +		addr = (void *)CBUS_FIRST0 + i * 16;
> +		set_bit(gpio, addr);
> +	} else {
> +		/* GPIO, clear CBUS 1 ~ 5 */
> +		i = 5;
> +	}
> +
> +	while (i--) {
> +		addr = (void *)CBUS_FIRST0 + 16 * i;
> +		clear_bit(gpio, addr);
> +	}
> +
> +	return 0;
> +}
> diff --git a/arch/mips/mach-lsmips/ls1c300/init.c b/arch/mips/mach-lsmips/ls1c300/init.c
> new file mode 100644
> index 0000000000..f86b6fd4f1
> --- /dev/null
> +++ b/arch/mips/mach-lsmips/ls1c300/init.c
> @@ -0,0 +1,59 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2020 MediaTek Inc.
> + *
> + * Author:  Gao Weijie <weijie.gao at mediatek.com>
> + *
> + * based on: arch/mips/mach-mtmips/mt7628/init.c
> + * Copyright (C) 2020-2022 Du Huanpeng <dhu at hodcarrier.org>
> + */
> +
> +#include <common.h>
> +#include <clk.h>
> +#include <dm.h>
> +#include <dm/uclass.h>
> +#include <dt-bindings/clock/ls1c300-clk.h>
> +#include <linux/io.h>
> +#include <linux/sizes.h>
> +
> +DECLARE_GLOBAL_DATA_PTR;
> +
> +int print_cpuinfo(void)
> +{
> +	struct udevice *udev;
> +	struct clk clk;
> +	int ret;
> +	ulong xtal;
> +	char buf[SZ_32];
> +
> +	printf("CPU: Loongson ls1c300b\n");
> +
> +	ret = uclass_get_device_by_driver(UCLASS_CLK, DM_DRIVER_GET(ls1c300_clk), &udev);
> +
> +	if (ret) {
> +		printf("error: clock driver not found.\n");
> +		return 0;
> +	}
> +
> +	clk.dev = udev;
> +
> +	clk.id = CLK_XTAL;
> +	xtal = clk_get_rate(&clk);

Same comments.

> +
> +	clk.id = CLK_CPU_THROT;
> +	gd->cpu_clk = clk_get_rate(&clk);
> +
> +	clk.id = CLK_SDRAM;
> +	gd->mem_clk = clk_get_rate(&clk);
> +
> +	printf("Clock: CPU: %sMHz, ", strmhz(buf, gd->cpu_clk));
> +	printf("SDRAM: %sMHz, ", strmhz(buf, gd->mem_clk));
> +	printf("XTAL: %sMHz\n", strmhz(buf, xtal));
> +
> +	return 0;
> +}
> +
> +ulong notrace get_tbclk(void)
> +{
> +	return gd->cpu_clk;
> +}
> diff --git a/arch/mips/mach-lsmips/ls1c300/lowlevel_init.S b/arch/mips/mach-lsmips/ls1c300/lowlevel_init.S
> new file mode 100644
> index 0000000000..a8d1359cf5
> --- /dev/null
> +++ b/arch/mips/mach-lsmips/ls1c300/lowlevel_init.S
> @@ -0,0 +1,136 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2020 MediaTek Inc.
> + *
> + * Author:  Gao Weijie <weijie.gao at mediatek.com>
> + *
> + * Copyright (C) 2020-2022 Du Huanpeng <dhu at hodcarrier.org>
> + */
> +
> +#include <config.h>
> +#include <asm-offsets.h>
> +#include <asm/cacheops.h>
> +#include <asm/regdef.h>
> +#include <asm/mipsregs.h>
> +#include <asm/addrspace.h>
> +#include <asm/asm.h>
> +#include <linux/sizes.h>
> +
> +/* PLL control register */
> +#define NAND_BASE	0xbfe70000
> +#define START_FREQ	0x8030
> +#define CLK_DIV_PARAM	0x8034
> +#define CPU_THROT	0xc010
> +
> +/* START_FREQ */
> +#define PLL_VALID	31
> +#define Reserved_24	24
> +#define FRAC_N		16
> +#define M_PLL		8
> +#define Reserved_4	4
> +#define RST_TIME	2
> +#define SDRAM_DIV	0
> + #define SDRAM_DIV2	0
> + #define SDRAM_DIV4	1
> + #define SDRAM_DIV3	2
> +
> +/* CLK_DIV_PARAM */
> +#define PIX_DIV		24
> +#define CAM_DIV		16
> +#define CPU_DIV		8
> +#define PIX_DIV_VALID	5
> +#define PIX_SEL		4
> +#define CAM_DIV_VALID	3
> +#define CAM_SEL		2
> +#define CPU_DIV_VALID	1
> +#define CPU_SEL		0
> +
> +/* Document:
> + * Freq_PLL = XIN *(M_PLL + FRAC_N)/4
> + */
> +#define XIN			24000000
> +#define PLL_VALID_1		(1<<PLL_VALID)
> +#define PREP_M_PLL(Freq_PLL)	(((Freq_PLL * 4) / XIN) << M_PLL)
> +#define PREP_SDRAM_DIV(div)	(div<<SDRAM_DIV)
> +#define PREP_CPU_DIV(div1)	((0x80|div1)<<CPU_DIV | (div1&&div1)<<CPU_DIV_VALID)
> +#define PREP_PIX_DIV(div2)	(div2<<PIX_DIV)
> +#define PREP_CAM_DIV(div3)	(div3<<CAM_DIV)
> +
> +/* PLL @264MHz, CPU @132MHz, SDRAM @66MHz */
> +#define CFG_START_FREQ		(PLL_VALID_1 | PREP_M_PLL(264000000) | SDRAM_DIV2)
> +#define CFG_CLK_DIV_PARAM	(PREP_CPU_DIV(2) | PREP_PIX_DIV(0x24) | PREP_CAM_DIV(0x24))
> +#define CFG_CPU_THROT		15
> +
> +/* SPI0 control register */
> +#define SPI0_BASE		0xbfe80000
> +#define SPCR			0
> +#define SPSR			1
> +#define TxFIFO			2
> +#define RxFIFO			2
> +#define SPER			3
> +#define SFC_PARAM		4
> +    #define CLK_DIV		4
> +    #define DUAL_IO		3
> +    #define FAST_READ		2
> +    #define BURST_EN		1
> +    #define MEMORY_EN		0
> +#define SFC_SOFTCS		5
> +#define SFC_TIMING		6
> +    #define T_FAST		2
> +    #define T_CSH		0
> +
> +	.set noreorder
> +LEAF(ls1c300_pll_init)
> +#if !CONFIG_IS_ENABLED(SKIP_LOWLEVEL_INIT)
> +	li	t0, NAND_BASE
> +	li	t1, CFG_START_FREQ
> +	li	t2, CFG_CLK_DIV_PARAM
> +	li	t3, CFG_CPU_THROT
> +
> +	sw	t3, CPU_THROT (t0)
> +	sw	t2, CLK_DIV_PARAM (t0)
> +	sw	t1, START_FREQ (t0)
> +	  nop
> +
> +	ori	t2, 1<<CPU_SEL
> +	sw	t2, CLK_DIV_PARAM (t0)
> +#endif
> +	li	v0, 264000000
> +	jr	ra
> +	nop
> +END(ls1c300_pll_init)
> +
> +LEAF(ls1c300_spi_init)
> +#if !CONFIG_IS_ENABLED(SKIP_LOWLEVEL_INIT)
> +	li	t0, SPI0_BASE
> +	li	t1, (1<<MEMORY_EN) | (1<<BURST_EN) | (1<<FAST_READ) | (1<<DUAL_IO)
> +	sb	t1, SFC_PARAM (t0)
> +	li	t2, (1<<T_FAST) | (1<<T_CSH)
> +	sb	t2, SFC_TIMING (t0)
> +#endif
> +	jr	ra
> +	  nop
> +END(ls1c300_spi_init)
> +
> +NESTED(lowlevel_init, 0, ra)
> +	/* Save ra and do real lowlevel initialization */
> +	move	s0, ra
> +	/* Setup PLL @264MHz */
> +	PTR_LA	t9, ls1c300_pll_init
> +	jalr	t9
> +	  nop
> +
> +	/* Setup SPI Dual IO at 33MHz */
> +	PTR_LA	t9, ls1c300_spi_init
> +	jalr	t9
> +	  nop
> +
> +	/* Setup external SDRAM @66MHz */
> +	PTR_LA	t9, ls1c300_sdram_init
> +	jalr	t9
> +	  nop
> +
> +	move	ra, s0
> +	jr	ra
> +	 nop
> +END(lowlevel_init)
> diff --git a/arch/mips/mach-lsmips/ls1c300/sdram.S b/arch/mips/mach-lsmips/ls1c300/sdram.S
> new file mode 100644
> index 0000000000..6b3a347508
> --- /dev/null
> +++ b/arch/mips/mach-lsmips/ls1c300/sdram.S
> @@ -0,0 +1,93 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2020-2022 Du Huanpeng <dhu at hodcarrier.org>
> + */
> +
> +#include <config.h>
> +#include <asm-offsets.h>
> +#include <asm/cacheops.h>
> +#include <asm/regdef.h>
> +#include <asm/mipsregs.h>
> +#include <asm/addrspace.h>
> +#include <asm/asm.h>
> +#include <linux/sizes.h>
> +
> +/* sdram control 64 bit register */
> +#define SD_CONFIG	0xbfd00000
> +#define SD_CONFIGHI	0x414
> +#define SD_CONFIGLO	0x410
> +
> +#define CONFIG_VALID	41
> +#define HANG_UP		40
> +#define DEF_SEL		39
> +#define TWR		37
> +#define TREF		25
> +#define TRAS		21
> +#define TRFC		17
> +#define TRP		14
> +#define TCL		11
> +#define TRCD		8
> +
> +#define SD_BIT		6
> +  #define SD_8BIT       (0<<SD_BIT)
> +  #define SD_16BIT      (1<<SD_BIT)
> +  #define SD_32BIT      (2<<SD_BIT)
> +#define SD_CSIZE	3
> +  #define SD_CSIZE_512	(0<<SD_CSIZE)
> +  #define SD_CSIZE_1K	(1<<SD_CSIZE)
> +  #define SD_CSIZE_2K	(2<<SD_CSIZE)
> +  #define SD_CSIZE_4K	(3<<SD_CSIZE)
> +  #define SD_CSIZE_256	(7<<SD_CSIZE)
> +#define SD_RSIZE	0
> +  #define SD_RSIZE_2K	(0<<SD_RSIZE)
> +  #define SD_RSIZE_4K	(1<<SD_RSIZE)
> +  #define SD_RSIZE_8K	(2<<SD_RSIZE)
> +  #define SD_RSIZE_16K	(3<<SD_RSIZE)
> +
> +#define SD_CFG_1(tWR, tREF, tRAS, tRFC, tRP, tCL, tRCD) \
> +	((tWR<<TWR)|(tREF<<TREF)|(tRAS<<TRAS)|(tRFC<<TRFC)|(tRP<<TRP)|(tCL<<TCL)|(tRCD<<TRCD))
> +#define CFG_SD_0(b, c, r) \
> +	((b<<SD_BIT)|(c<<SD_CSIZE)|(r<<SD_RSIZE))
> +
> +/* recommended values by ls1c300 user manual,
> + * tweat to fit your board.
> + */
> +#define SD_CONFIG_133MHz	SD_CFG_1(2, 0x818, 6, 8, 3, 3, 3)
> +#define SD_CONFIG_100MHz	SD_CFG_1(2, 0x620, 5, 6, 2, 3, 2)
> +#define SD_CONFIG_75MHz		SD_CFG_1(1, 0x494, 4, 5, 2, 2, 2)
> +#define SD_CONFIG_33MHz		SD_CFG_1(1, 0x204, 2, 2, 1, 2, 1)
> +
> +#define SD_CONFIG_66MHz		SD_CFG_1(1, 0x401, 4, 4, 2, 2, 2)
> +
> +#define SD_CONFIG64	(SD_CONFIG_66MHz | SD_16BIT | SD_CSIZE_1K | SD_RSIZE_8K)
> +#define CFG_SDCONFIGHI	(SD_CONFIG64 /(1<<32))
> +#define CFG_SDCONFIGLO	(SD_CONFIG64 %(1<<32))
> +
> +	.set noreorder
> +/* Loongson ls1c300 SoC do not have onchip sram for initial stack,
> + * initialize the external sdram on reset as early as possiable.
> + */

nit: multi-line comments have a leading blank line

> +LEAF(ls1c300_sdram_init)
> +#if !CONFIG_IS_ENABLED(SKIP_LOWLEVEL_INIT)
> +	li	t0, SD_CONFIG
> +	li	t1, CFG_SDCONFIGLO
> +	li	t2, CFG_SDCONFIGHI
> +
> +	sw	t1, SD_CONFIGLO (t0)
> +	sw	t2, SD_CONFIGHI (t0)
> +	nop
> +
> +	sw	t1, SD_CONFIGLO (t0)
> +	sw	t2, SD_CONFIGHI (t0)
> +	nop
> +
> +	ori	t2, 1<<(CONFIG_VALID-32)
> +	sw	t1, SD_CONFIGLO (t0)
> +	sw	t2, SD_CONFIGHI (t0)
> +#endif
> +	li	v0, SZ_64M
> +	jr	ra
> +	 nop
> +END(ls1c300_sdram_init)
> +
> +
> diff --git a/arch/mips/mach-lsmips/ls1c300/serial.c b/arch/mips/mach-lsmips/ls1c300/serial.c
> new file mode 100644
> index 0000000000..e13762d973
> --- /dev/null
> +++ b/arch/mips/mach-lsmips/ls1c300/serial.c
> @@ -0,0 +1,109 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2020 MediaTek Inc.
> + *
> + * Author:  Gao Weijie <weijie.gao at mediatek.com>
> + *
> + * Copyright (C) 2020-2022 Du Huanpeng <dhu at hodcarrier.org>
> + */
> +
> +#include <mach/serial.h>
> +#include <linux/kernel.h>
> +
> +struct uart_pin_config {
> +	char port;
> +	char af;
> +	char rx;
> +	char tx;
> +};
> +
> +struct uart_pin_config con[] = {
> +#if CONFIG_CONS_INDEX == 0
> +{ 0, 2, 74, 75 },
> +{ 0, 3, 23, 24 },
> +{ 0, 3, 99, 100 },
> +
> +#elif CONFIG_CONS_INDEX == 1
> +{ 1, 1, 17, 18 },
> +{ 1, 1, 101, 102 },
> +{ 1, 2, 40, 41 },
> +{ 1, 4, 2, 3 },
> +
> +#elif CONFIG_CONS_INDEX == 2
> +{ 2, 2, 36, 37 },
> +{ 2, 2, 42, 43 },
> +{ 2, 3, 27, 28 },
> +{ 2, 3, 103, 104 },
> +{ 2, 4, 4, 5 },
> +
> +#elif CONFIG_CONS_INDEX == 3
> +{ 3, 2, 17, 18 },
> +{ 3, 2, 33, 34 },
> +{ 3, 2, 44, 45 },
> +{ 3, 4, 0, 1 },
> +
> +#elif CONFIG_CONS_INDEX == 4
> +{ 4, 5, 23, 24 },
> +{ 4, 5, 58, 59 },
> +{ 4, 5, 80, 79 },
> +
> +#elif CONFIG_CONS_INDEX == 5
> +{ 5, 5, 25, 26 },
> +{ 5, 5, 60, 61 },
> +{ 5, 5, 81, 78 },
> +
> +#elif CONFIG_CONS_INDEX == 6
> +{ 6, 5, 27, 46 },
> +{ 6, 5, 62, 63 },
> +
> +#elif CONFIG_CONS_INDEX == 7
> +{ 7, 5, 57, 56 },
> +{ 7, 5, 64, 65 },
> +{ 7, 5, 87, 88 },
> +
> +#elif CONFIG_CONS_INDEX == 8
> +{ 8, 5, 55, 54 },
> +{ 8, 5, 66, 67 },
> +{ 8, 5, 89, 90 },
> +
> +#elif CONFIG_CONS_INDEX == 9
> +{ 9, 5, 53, 52 },
> +{ 9, 5, 68, 69 },
> +{ 9, 5, 85, 86 },
> +
> +#elif CONFIG_CONS_INDEX == 10
> +{ 10, 5, 51, 50 },
> +{ 10, 5, 70, 71 },
> +{ 10, 5, 84, 82 },
> +
> +#elif CONFIG_CONS_INDEX == 11
> +{ 11, 5, 49, 48 },
> +{ 11, 5, 72, 73 },
> +#endif /* CONFIG_CONS_INDEX */
> +};
> +
> +#define UART2_RX	36
> +#define UART2_TX	37
> +#define AFUNC		2
> +
> +void lsmips_spl_serial_init(void)
> +{
> +#ifdef CONFIG_SPL_SERIAL
> +	int pin_rx, pin_tx;
> +	int afunc;
> +
> +	if (CONFIG_CONS_PIN < ARRAY_SIZE(con)) {
> +		pin_rx = con[CONFIG_CONS_PIN].rx;
> +		pin_tx = con[CONFIG_CONS_PIN].tx;
> +		afunc = con[CONFIG_CONS_PIN].af;
> +	} else {
> +		pin_rx = UART2_RX;
> +		pin_tx = UART2_TX;
> +		afunc = AFUNC;
> +	}
> +
> +	gpio_set_alternate(pin_rx, afunc);
> +	gpio_set_alternate(pin_tx, afunc);
> +#endif /* CONFIG_SPL_SERIAL */
> +	return ;
> +}

same comments

> diff --git a/arch/mips/mach-lsmips/spl.c b/arch/mips/mach-lsmips/spl.c
> new file mode 100644
> index 0000000000..c7c28989f2
> --- /dev/null
> +++ b/arch/mips/mach-lsmips/spl.c
> @@ -0,0 +1,47 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2020 MediaTek Inc. All Rights Reserved.
> + *
> + * Author: Gao Weijie <weijie.gao at mediatek.com>
> + *
> + * Copyright (C) 2022 Du Huanpeng <dhu at hodcarrier.org>
> + */
> +
> +#include <common.h>
> +#include <init.h>
> +#include <spl.h>
> +#include <asm/sections.h>
> +#include <linux/libfdt.h>
> +#include <linux/sizes.h>
> +#include <mach/serial.h>
> +
> +void __noreturn board_init_f(ulong dummy)
> +{
> +	spl_init();
> +
> +#ifdef CONFIG_SPL_SERIAL
> +	/*
> +	 * lsmips_spl_serial_init() is useful if debug uart is enabled,
> +	 * or DM based serial is not enabled.
> +	 */
> +	lsmips_spl_serial_init();
> +	preloader_console_init();
> +#endif
> +
> +	board_init_r(NULL, 0);
> +}
> +
> +void board_boot_order(u32 *spl_boot_list)
> +{
> +	spl_boot_list[0] = BOOT_DEVICE_NOR;
> +}
> +
> +unsigned long spl_nor_get_uboot_base(void)
> +{
> +	void *uboot_base = __image_copy_end;
> +
> +	if (fdt_magic(uboot_base) == FDT_MAGIC)
> +		return (unsigned long)uboot_base + fdt_totalsize(uboot_base);
> +
> +	return (unsigned long)uboot_base;
> +}
> diff --git a/board/loongson/ls1c300-eval/Kconfig b/board/loongson/ls1c300-eval/Kconfig
> new file mode 100644
> index 0000000000..e427570a83
> --- /dev/null
> +++ b/board/loongson/ls1c300-eval/Kconfig
> @@ -0,0 +1,12 @@
> +if BOARD_LS1C300
> +
> +config SYS_BOARD
> +	default "ls1c300-eval"
> +
> +config SYS_VENDOR
> +	default "loongson"
> +
> +config SYS_CONFIG_NAME
> +	default "ls1c300"
> +
> +endif
> diff --git a/board/loongson/ls1c300-eval/MAINTAINERS b/board/loongson/ls1c300-eval/MAINTAINERS
> new file mode 100644
> index 0000000000..5420198dab
> --- /dev/null
> +++ b/board/loongson/ls1c300-eval/MAINTAINERS
> @@ -0,0 +1,7 @@
> +LS1C300_EVAL BOARD
> +M:	Du Huanpeng<dhu at hodcarrier.org>
> +S:	Maintained
> +F:	board/loongson/ls1c300-eval
> +F:	include/configs/ls1c300.h
> +F:	configs/ls1c300_defconfig
> +F:	arch/mips/dts/ls1c300-eval.dts
> diff --git a/board/loongson/ls1c300-eval/Makefile b/board/loongson/ls1c300-eval/Makefile
> new file mode 100644
> index 0000000000..db129c5aba
> --- /dev/null
> +++ b/board/loongson/ls1c300-eval/Makefile
> @@ -0,0 +1,3 @@
> +# SPDX-License-Identifier: GPL-2.0
> +
> +obj-y += board.o
> diff --git a/board/loongson/ls1c300-eval/board.c b/board/loongson/ls1c300-eval/board.c
> new file mode 100644
> index 0000000000..2f588a0dcb
> --- /dev/null
> +++ b/board/loongson/ls1c300-eval/board.c
> @@ -0,0 +1,20 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2020-2022 Du Huanpeng <dhu at hodcarrier.org>
> + */
> +
> +#include <common.h>
> +#include <mach/serial.h>
> +
> +#ifdef CONFIG_DEBUG_UART_BOARD_INIT
> +
> +#define UART2_RX	36
> +#define UART2_TX	37
> +#define AFUNC		2
> +
> +void board_debug_uart_init(void)
> +{
> +	gpio_set_alternate(UART2_TX, AFUNC);
> +	gpio_set_alternate(UART2_RX, AFUNC);
> +}
> +#endif
> diff --git a/configs/ls1c300_defconfig b/configs/ls1c300_defconfig
> new file mode 100644
> index 0000000000..3f0689c7f9
> --- /dev/null
> +++ b/configs/ls1c300_defconfig
> @@ -0,0 +1,54 @@
> +CONFIG_MIPS=y
> +CONFIG_SYS_MALLOC_F_LEN=0x40000
> +CONFIG_SPL_LIBCOMMON_SUPPORT=y
> +CONFIG_SPL_LIBGENERIC_SUPPORT=y
> +CONFIG_NR_DRAM_BANKS=1
> +CONFIG_ENV_SIZE=0x1000
> +CONFIG_DEFAULT_DEVICE_TREE="ls1c300-eval"
> +CONFIG_SPL_SERIAL=y
> +CONFIG_SPL_SIZE_LIMIT=0x100000
> +CONFIG_SPL=y
> +CONFIG_DEBUG_UART_BOARD_INIT=y
> +CONFIG_DEBUG_UART_BASE=0xbfe48000
> +CONFIG_DEBUG_UART_CLOCK=66000000
> +CONFIG_ARCH_LSMIPS=y
> +CONFIG_SPL_PAYLOAD="u-boot.img"
> +CONFIG_ROM_EXCEPTION_VECTORS=y
> +# CONFIG_MIPS_CACHE_SETUP is not set
> +# CONFIG_MIPS_CACHE_DISABLE is not set
> +CONFIG_RESTORE_EXCEPTION_VECTOR_BASE=y
> +CONFIG_MIPS_BOOT_FDT=y
> +CONFIG_DEBUG_UART=y
> +CONFIG_SYS_LOAD_ADDR=0x80010000
> +CONFIG_FIT=y
> +# CONFIG_ARCH_FIXUP_FDT_MEMORY is not set
> +CONFIG_LOGLEVEL=9
> +CONFIG_DISPLAY_CPUINFO=y
> +CONFIG_DISPLAY_BOARDINFO_LATE=y
> +CONFIG_SPL_LEGACY_IMAGE_CRC_CHECK=y
> +CONFIG_SPL_SYS_MALLOC_SIMPLE=y
> +CONFIG_SPL_NOR_SUPPORT=y
> +# CONFIG_CMD_ELF is not set
> +# CONFIG_CMD_XIMG is not set
> +# CONFIG_CMD_CRC32 is not set
> +CONFIG_CMD_CLK=y
> +# CONFIG_CMD_LOADS is not set
> +# CONFIG_PARTITIONS is not set
> +CONFIG_OF_EMBED=y
> +CONFIG_SYS_RELOC_GD_ENV_ADDR=y
> +# CONFIG_NET is not set
> +CONFIG_CLK=y
> +CONFIG_SPL_CLK_CCF=y
> +# CONFIG_INPUT is not set
> +# CONFIG_POWER is not set
> +CONFIG_CONS_INDEX=2
> +CONFIG_DEBUG_UART_ANNOUNCE=y
> +CONFIG_SYS_NS16550=y
> +CONFIG_SPI=y
> +CONFIG_SYSRESET=y
> +CONFIG_SYSRESET_WATCHDOG=y
> +CONFIG_SYSRESET_WATCHDOG_AUTO=y
> +CONFIG_WATCHDOG_TIMEOUT_MSECS=3000
> +CONFIG_WDT_LSMIPS=y
> +CONFIG_REGEX=y
> +# CONFIG_GZIP is not set
> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
> index bb4eee5d99..51562ca4a6 100644
> --- a/drivers/clk/Makefile
> +++ b/drivers/clk/Makefile
> @@ -17,6 +17,7 @@ obj-y += tegra/
>   obj-y += ti/
>   obj-$(CONFIG_$(SPL_TPL_)CLK_INTEL) += intel/
>   obj-$(CONFIG_ARCH_ASPEED) += aspeed/
> +obj-$(CONFIG_ARCH_LSMIPS) += lsmips/
>   obj-$(CONFIG_ARCH_MEDIATEK) += mediatek/
>   obj-$(CONFIG_ARCH_MESON) += meson/
>   obj-$(CONFIG_ARCH_MTMIPS) += mtmips/
> diff --git a/drivers/clk/lsmips/Makefile b/drivers/clk/lsmips/Makefile
> new file mode 100644
> index 0000000000..0a47269cd3
> --- /dev/null
> +++ b/drivers/clk/lsmips/Makefile
> @@ -0,0 +1,3 @@
> +# SPDX-License-Identifier: GPL-2.0
> +
> +obj-$(CONFIG_SOC_LS1C300) += clk-ls1c300.o
> diff --git a/drivers/clk/lsmips/clk-ls1c300.c b/drivers/clk/lsmips/clk-ls1c300.c
> new file mode 100644
> index 0000000000..fe274e2570
> --- /dev/null
> +++ b/drivers/clk/lsmips/clk-ls1c300.c
> @@ -0,0 +1,161 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * reference:
> + *   drivers/clk/microchip/mpfs_clk.c
> + *   drivers/clk/clk_octeon.c
> + *
> + * Copyright (C) 2020-2022 Du Huanpeng <dhu at hodcarrier.org>
> + */
> +
> +#include <common.h>
> +#include <clk-uclass.h>
> +#include <dm.h>
> +#include <dt-bindings/clock/ls1c300-clk.h>
> +#include <linux/bitops.h>
> +#include <linux/bitfield.h>
> +#include <linux/io.h>
> +#include <linux/clk-provider.h>
> +
> +/* PLL/SDRAM Frequency Configuration Register */
> +#define START_FREQ	0
> +#define CLK_DIV_PARAM	4
> +
> +/* START_FREQ */
> +#define	PLL_VALID	BIT(31)
> +#define	RESERVED0	GENMASK(30, 24)
> +#define	FRAC_N		GENMASK(23, 16)
> +#define	M_PLL		GENMASK(15, 8)
> +#define	RESERVED1	GENMASK(7, 4)
> +#define	RST_TIME	GENMASK(3, 2)
> +#define	SDRAM_DIV	GENMASK(1, 0)
> +/* CLK_DIV_PARAM */
> +#define	PIX_DIV		GENMASK(31, 24)
> +#define	CAM_DIV		GENMASK(23, 16)
> +#define	CPU_DIV		GENMASK(15, 8)
> +#define	RESERVED2	GENMASK(7, 6)
> +#define	PIX_DIV_VALID	BIT(5)
> +#define	PIX_SEL		BIT(4)
> +#define	CAM_DIV_VALID	BIT(3)
> +#define	CAM_SEL		BIT(2)
> +#define	CPU_DIV_VALID	BIT(1)
> +#define	CPU_SEL		BIT(0)
> +/* CPU_THROT */
> +#define	CPU_THROT	GENMASK(3, 0)
> +
> +static const struct clk_div_table sdram_div_table[] = {
> +	{.val = 0, .div = 2},
> +	{.val = 1, .div = 4},
> +	{.val = 2, .div = 3},
> +	{.val = 3, .div = 3},
> +};
> +
> +ulong ls1c300_pll_get_rate(struct clk *clk)
> +{
> +	unsigned int mult, div;
> +	unsigned int val;
> +	long long parent_rate;
> +	void *base;
> +
> +	parent_rate = clk_get_parent_rate(clk);
> +	base = (void *)clk->data;
> +	val = readl(base + START_FREQ);
> +
> +	mult = FIELD_GET(FRAC_N, val) + FIELD_GET(M_PLL, val);

This doesn't seem right. Shouldn't the fractional part be a fraction? E.g.
something like

return parent_rate * (M_PLL << 8 + FRAC_N) >> 10;

I know what you have here obstensibly matches the manual, but it seems like
it was written such that the fractional part was already scaled. Can you try
setting the fractional part and determine the actual formula?

> +	div = 4;
> +	val = (mult * parent_rate) / div;

Just divide by 4. You can also return directly.

> +
> +	return val;
> +}
> +
> +static ulong ls1c300_clk_get_rate(struct clk *clk)
> +{
> +	struct clk *cl;
> +	ulong rate;
> +	int err;
> +
> +	err = clk_get_by_id(clk->id, &cl);
> +	if (err)
> +		return err;
> +
> +	rate = clk_get_rate(cl);
> +	return rate;
> +}
> +
> +static int ls1c300_clk_probe(struct udevice *dev)
> +{
> +	void __iomem *base;
> +	void __iomem *cpu_throt;
> +	void __iomem *addr;
> +
> +	struct clk *cl, clk;
> +
> +	int ret;
> +	const char *parent_name;
> +	unsigned int mult, div;
> +	int flags;
> +
> +	base = (void *)dev_remap_addr_index(dev, 0);
> +	cpu_throt  = (void *)dev_remap_addr_index(dev, 1);
> +
> +	ret = clk_get_by_index(dev, 0, &clk);
> +	if (ret)
> +		return ret;
> +
> +	ret = clk_get_rate(&clk);
> +
> +	parent_name = clk.dev->name;
> +
> +	cl = kzalloc(sizeof(*cl), GFP_KERNEL);
> +	cl->data = (unsigned long)base;
> +	ret = clk_register(cl, "clk-ls1c300-pll", "pll", parent_name);
> +	clk_dm(CLK_PLL, cl);
> +
> +	addr = base + CLK_DIV_PARAM;
> +	flags = CLK_DIVIDER_ONE_BASED | CLK_DIVIDER_ALLOW_ZERO;
> +	cl = clk_register_divider(NULL, "cpu_div", "pll", 0, addr,  8, 7, flags);
> +	clk_dm(CLK_CPU, cl);
> +	cl = clk_register_divider(NULL, "cam_div", "pll", 0, addr, 16, 7, flags);
> +	clk_dm(CLK_CAMERA, cl);
> +	cl = clk_register_divider(NULL, "pix_div", "pll", 0, addr, 24, 7, flags);
> +	clk_dm(CLK_PIX, cl);
> +
> +	mult = FIELD_GET(CPU_THROT, readl(cpu_throt)) + 1;
> +	div = 16;
> +	cl = clk_register_fixed_factor(NULL, "cpu_throt_factor", "cpu_div", CLK_GET_RATE_NOCACHE, mult, div);

Please break this line at 80 characters.

> +	clk_dm(CLK_CPU_THROT, cl);
> +
> +	addr = base + START_FREQ;
> +	cl = clk_register_divider(NULL, "sdram_div", "cpu_div", 0, addr, 0, 2, 0);
> +	to_clk_divider(cl)->table = sdram_div_table;

Same feedback.

> +	clk_dm(CLK_SDRAM, cl);
> +
> +	return 0;
> +}
> +
> +static const struct udevice_id ls1c300_clk_ids[] = {
> +	{ .compatible = "loongson,ls1c300-clk" },
> +	{ }
> +};
> +
> +struct clk_ops clk_ls1c300_pll_ops = {
> +	.get_rate = ls1c300_pll_get_rate,
> +};
> +
> +static const struct clk_ops ls1c300_clk_ops = {
> +	.get_rate = ls1c300_clk_get_rate,
> +};
> +
> +U_BOOT_DRIVER(clk_ls1c300_pll) = {
> +	.name	= "clk-ls1c300-pll",
> +	.id	= UCLASS_CLK,
> +	.ops	= &clk_ls1c300_pll_ops,
> +};
> +

Can you group these together? E.g. define the PLL stuff, and then the
generic clock stuff.

> +U_BOOT_DRIVER(ls1c300_clk) = {
> +	.name = "ls1c300-clk",
> +	.id = UCLASS_CLK,
> +	.of_match = ls1c300_clk_ids,
> +	.probe = ls1c300_clk_probe,
> +	.priv_auto = sizeof(struct clk),
> +	.ops = &ls1c300_clk_ops,
> +};
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 5b614cfa6e..a9af5e5eb6 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -168,6 +168,14 @@ config WDT_GPIO
>   	  doc/device-tree-bindings/watchdog/gpio-wdt.txt for
>   	  information on how to describe the watchdog in device tree.
>   
> +config WDT_LSMIPS
> +	bool "Loongson MIPS watchdog timer support"
> +	depends on WDT
> +	help
> +	  Select this to enable watchdog timer for Loongson SoCs.
> +	  The watchdog timer is stopped when initialized.
> +	  It performs full SoC reset.
> +
>   config WDT_MPC8xx
>   	bool "MPC8xx watchdog timer support"
>   	depends on WDT && MPC8xx
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index a35bd559f5..cb596af904 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -27,6 +27,7 @@ obj-$(CONFIG_WDT_CORTINA) += cortina_wdt.o
>   obj-$(CONFIG_WDT_ORION) += orion_wdt.o
>   obj-$(CONFIG_WDT_CDNS) += cdns_wdt.o
>   obj-$(CONFIG_WDT_GPIO) += gpio_wdt.o
> +obj-$(CONFIG_WDT_LSMIPS) += lsmips_wdt.o
>   obj-$(CONFIG_WDT_MPC8xx) += mpc8xx_wdt.o
>   obj-$(CONFIG_WDT_MT7620) += mt7620_wdt.o
>   obj-$(CONFIG_WDT_MT7621) += mt7621_wdt.o
> diff --git a/drivers/watchdog/lsmips_wdt.c b/drivers/watchdog/lsmips_wdt.c
> new file mode 100644
> index 0000000000..1e0c4a3a7c
> --- /dev/null
> +++ b/drivers/watchdog/lsmips_wdt.c
> @@ -0,0 +1,131 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Watchdog driver for MediaTek SoCs
> + *
> + * Copyright (C) 2018 MediaTek Inc.
> + * Author: Ryder Lee <ryder.lee at mediatek.com>
> + *
> + * based on: drivers/watchdog/mtk_wdt.c
> + * Copyright (C) 2020-2022 Du Huanpeng <dhu at hodcarrier.org>
> + */
> +
> +#include <common.h>
> +#include <dm.h>
> +#include <hang.h>
> +#include <wdt.h>
> +#include <asm/io.h>
> +#include <clk.h>
> +
> +
> +struct lsmips_wdt_priv {
> +	void __iomem *base;
> +#define WDT_EN		0
> +#define WDT_TIMER	4
> +#define WDT_SET		8
> +	ulong clock;
> +	unsigned long timeout;
> +};
> +
> +static int lsmips_wdt_reset(struct udevice *dev)
> +{
> +	struct lsmips_wdt_priv *priv = dev_get_priv(dev);
> +
> +	writel(priv->timeout, priv->base + WDT_TIMER);
> +	writel(1, priv->base + WDT_SET);
> +
> +	return 0;
> +}
> +
> +static int lsmips_wdt_stop(struct udevice *dev)
> +{
> +	struct lsmips_wdt_priv *priv = dev_get_priv(dev);
> +
> +	writel(0, priv->base + WDT_EN);
> +	return 0;
> +}
> +
> +static int lsmips_wdt_expire_now(struct udevice *dev, ulong flags)
> +{
> +	struct lsmips_wdt_priv *priv = dev_get_priv(dev);
> +
> +	writel(1, priv->base + WDT_EN);
> +	writel(1, priv->base + WDT_TIMER);
> +	writel(1, priv->base + WDT_SET);
> +
> +	hang();
> +	return 0;
> +}
> +
> +static int lsmips_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
> +{
> +	struct lsmips_wdt_priv *priv = dev_get_priv(dev);
> +	unsigned int timeout;
> +
> +	timeout = U32_MAX / (priv->clock / 1000);
> +
> +	if (timeout < timeout_ms)
> +		timeout = U32_MAX;
> +	else
> +		timeout = timeout_ms * (priv->clock / 1000);
> +
> +	debug("WDT: reload  = %08x\n", timeout);
> +
> +	writel(1, priv->base + WDT_EN);
> +	writel(timeout, priv->base + WDT_TIMER);
> +	writel(1, priv->base + WDT_SET);
> +
> +	priv->timeout = timeout;
> +
> +	return 0;
> +}
> +
> +static int lsmips_wdt_probe(struct udevice *dev)
> +{
> +	struct lsmips_wdt_priv *priv = dev_get_priv(dev);
> +	struct clk cl;
> +
> +	priv->base = dev_remap_addr(dev);
> +	if (!priv->base)
> +		return -ENOENT;
> +
> +	if (clk_get_by_index(dev, 0, &cl) == 0)
> +		priv->clock = clk_get_rate(&cl);
> +
> +	if (priv->clock < 45000000 || priv->clock > 133000000) {
> +		/*
> +		 * according to datasheet, the SDRAM works at the range frequency of 45~133MHz,
> +		 * the watchdog's clock is the same with the SDRAM, see page 32.
> +		 * so, if we got a clock out of this range,
> +		 * probably the clock is wrong or working without SDRAM.
> +		 * assign a default value 1^26 in this case.
> +		 */
> +		priv->clock = 67108864;

Use whatever clock you get. If it's wrong that's a clock driver bug.

> +	}
> +
> +	debug("WDT: clock = %ld\n", priv->clock);
> +
> +	writel(0, priv->base + WDT_EN);
> +	return 0;
> +}
> +
> +static const struct wdt_ops lsmips_wdt_ops = {
> +	.start = lsmips_wdt_start,
> +	.reset = lsmips_wdt_reset,
> +	.stop = lsmips_wdt_stop,
> +	.expire_now = lsmips_wdt_expire_now,
> +};
> +
> +static const struct udevice_id lsmips_wdt_ids[] = {
> +	{ .compatible = "loongson,ls1c300-wdt"},
> +	{}
> +};
> +
> +U_BOOT_DRIVER(lsmips_wdt) = {
> +	.name = "lsmips_wdt",
> +	.id = UCLASS_WDT,
> +	.of_match = lsmips_wdt_ids,
> +	.priv_auto = sizeof(struct lsmips_wdt_priv),
> +	.probe = lsmips_wdt_probe,
> +	.ops = &lsmips_wdt_ops,
> +	.flags = DM_FLAG_PRE_RELOC,
> +};
> diff --git a/include/configs/ls1c300.h b/include/configs/ls1c300.h
> new file mode 100644
> index 0000000000..c460b4564b
> --- /dev/null
> +++ b/include/configs/ls1c300.h
> @@ -0,0 +1,59 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2020 MediaTek Inc.
> + *
> + * Author: Gao Weijie <weijie.gao at mediatek.com>
> + * based on: include/configs/mt7628.h
> + * Copyright (C) 2022 Du Huanpeng <dhu at hodcarrier.org>
> + */
> +
> +#ifndef __CONFIG_LS1C300_H__
> +#define __CONFIG_LS1C300_H__
> +
> +#define CONFIG_SYS_HZ			1000
> +
> +#define CONFIG_SYS_BOOTPARAMS_LEN	0x20000
> +
> +#define CONFIG_SYS_SDRAM_BASE		0x80000000
> +#define CONFIG_SYS_LOAD_ADDR		0x80010000
> +
> +#define CONFIG_SYS_INIT_SP_OFFSET	0x80000
> +
> +#define CONFIG_SYS_BOOTM_LEN		0x1000000
> +
> +#define CONFIG_SYS_MAXARGS		16
> +#define CONFIG_SYS_CBSIZE		1024
> +
> +/* Serial SPL */
> +#define CONFIG_SYS_NS16550_SERIAL
> +#if defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_SERIAL)
> +#define CONFIG_SYS_NS16550_CLK		66000000
> +#define CONFIG_SYS_NS16550_REG_SIZE	(-1)
> +#define CONFIG_SYS_NS16550_COM1		0xbfe44000
> +#define CONFIG_SYS_NS16550_COM2		0xbfe48000
> +#define CONFIG_SYS_NS16550_COM3		0xbfe4c000
> +#define CONFIG_SYS_NS16550_COM4		0xbfe4c400
> +#define CONFIG_SYS_NS16550_COM5		0xbfe4c500
> +#define CONFIG_SYS_NS16550_COM6		0xbfe4c600
> +#endif
> +
> +/* Serial common */
> +#define CONFIG_SYS_BAUDRATE_TABLE	{ 9600, 19200, 38400, 57600, 115200, 230400, 460800, 921600 }
> +
> +/* SPL */
> +#if defined(CONFIG_SPL) && !defined(CONFIG_SPL_BUILD)
> +#define CONFIG_SKIP_LOWLEVEL_INIT	1
> +#endif
> +
> +#define CONFIG_SYS_UBOOT_START		CONFIG_SYS_TEXT_BASE
> +#define CONFIG_SPL_BSS_START_ADDR	0x80010000
> +#define CONFIG_SPL_BSS_MAX_SIZE		0x10000
> +#define CONFIG_SPL_MAX_SIZE		0x10000
> +#define CONFIG_SPL_PAD_TO		0
> +
> +#define CONFIG_MALLOC_F_ADDR		0x80100000	/* FIXME: find a proper place */
> +
> +/* Dummy value */
> +#define CONFIG_SYS_UBOOT_BASE		0
> +
> +#endif /* __CONFIG_LS1C300_H__ */
> diff --git a/include/dt-bindings/clock/ls1c300-clk.h b/include/dt-bindings/clock/ls1c300-clk.h
> new file mode 100644
> index 0000000000..735fa61789
> --- /dev/null
> +++ b/include/dt-bindings/clock/ls1c300-clk.h
> @@ -0,0 +1,48 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2022 Du Huanpeng <dhu at hodcarrier.org>
> + */
> +
> +#ifndef __DT_BINDINGS_LS1C300_CLK_H__
> +#define __DT_BINDINGS_LS1C300_CLK_H__
> +
> +/* Base clocks */
> +#define CLK_XTAL	0
> +#define CLK_PLL		1
> +#define CLK_CPU		2
> +#define CLK_CPU_THROT	7
> +#define CLK_SDRAM	3
> +
> +#define CLK_CAMERA	4
> +#define CLK_DC		5
> +#define CLK_PIX		5
> +#define CLK_AXIMUX	6
> +
> +/* Peripheral clocks */
> +#define CLK_UART0	3
> +#define CLK_UART1	3
> +#define CLK_UART2	3
> +#define CLK_UART3	3
> +#define CLK_UART4	3
> +#define CLK_UART5	3
> +#define CLK_UART6	3
> +#define CLK_UART7	3
> +#define CLK_UART8	3
> +#define CLK_UART9	3
> +#define CLK_UART10	3
> +#define CLK_UART11	3
> +#define CLK_CAN0	3
> +#define CLK_CAN1	3
> +#define CLK_I2C0	3
> +#define CLK_PWM		3
> +#define CLK_I2S		3
> +#define CLK_RTC		3
> +#define CLK_I2C1	3
> +#define CLK_SDIO	3
> +#define CLK_I2C2	3
> +#define CLK_ADC		3
> +#define CLK_NAND	3
> +
> +#define CLK_WDT		3

As commented last time, just have one CLK_APB.

--Sean


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