[PATCH RESEND v4 7/8] RISC-V: add LiteX SoC and linux-on-litex-vexriscv support
Antony Pavlov
antonynpavlov at gmail.com
Mon Aug 30 21:38:38 PDT 2021
On Mon, 23 Aug 2021 14:06:09 +0200
Ahmad Fatoum <a.fatoum at pengutronix.de> wrote:
Hi Ahmad!
> On 17.08.21 12:11, Antony Pavlov wrote:
> > LiteX is a Migen-based System on Chip, supporting softcore
> > VexRiscv CPU, a 32-bits Linux Capable RISC-V CPU.
> >
> > See https://github.com/enjoy-digital/litex and
> > https://github.com/litex-hub/linux-on-litex-vexriscv
> > for details.
> >
> > Signed-off-by: Antony Pavlov <antonynpavlov at gmail.com>
> > ---
> > arch/riscv/Kconfig.socs | 14 +++
> > arch/riscv/boards/Makefile | 1 +
> > arch/riscv/boards/litex-linux/Makefile | 3 +
> > arch/riscv/boards/litex-linux/lowlevel.c | 22 ++++
> > arch/riscv/dts/Makefile | 1 +
> > arch/riscv/dts/litex-linux.dts | 92 +++++++++++++++++
> > arch/riscv/dts/litex_soc_linux.dtsi | 49 +++++++++
> > arch/riscv/include/asm/debug_ll.h | 3 +
> > arch/riscv/include/asm/debug_ll_litex.h | 123 +++++++++++++++++++++++
> > common/Kconfig | 4 +
> > images/Makefile.riscv | 4 +
> > 11 files changed, 316 insertions(+)
> >
> > diff --git a/arch/riscv/Kconfig.socs b/arch/riscv/Kconfig.socs
> > index 221ea133d4..5c281918d5 100644
> > --- a/arch/riscv/Kconfig.socs
> > +++ b/arch/riscv/Kconfig.socs
> > @@ -95,4 +95,18 @@ config SIFIVE_L2
> > bool "SiFive L2 cache controller"
> > depends on CPU_SIFIVE
> >
> > +config SOC_LITEX
> > + bool "LiteX SoCs"
> > + depends on ARCH_RV32I
> > + select HAS_ASM_DEBUG_LL
> > + select HAS_NMON
> > + select USE_COMPRESSED_DTB
> > + select RISCV_TIMER
> > +
> > +config BOARD_LITEX_LINUX
> > + bool "litex linux board"
> > + depends on SOC_LITEX
> > + select RISCV_M_MODE
> > + def_bool y
> > +
> > endmenu
> > diff --git a/arch/riscv/boards/Makefile b/arch/riscv/boards/Makefile
> > index cb28a25d8b..8d5d9d4fc6 100644
> > --- a/arch/riscv/boards/Makefile
> > +++ b/arch/riscv/boards/Makefile
> > @@ -2,3 +2,4 @@
> > obj-$(CONFIG_BOARD_ERIZO_GENERIC) += erizo/
> > obj-$(CONFIG_BOARD_HIFIVE) += hifive/
> > obj-$(CONFIG_BOARD_BEAGLEV) += beaglev/
> > +obj-$(CONFIG_BOARD_LITEX_LINUX) += litex-linux/
> > diff --git a/arch/riscv/boards/litex-linux/Makefile b/arch/riscv/boards/litex-linux/Makefile
> > new file mode 100644
> > index 0000000000..3d217ffe0b
> > --- /dev/null
> > +++ b/arch/riscv/boards/litex-linux/Makefile
> > @@ -0,0 +1,3 @@
> > +# SPDX-License-Identifier: GPL-2.0
> > +
> > +pbl-y += lowlevel.o
> > diff --git a/arch/riscv/boards/litex-linux/lowlevel.c b/arch/riscv/boards/litex-linux/lowlevel.c
> > new file mode 100644
> > index 0000000000..da23ef5633
> > --- /dev/null
> > +++ b/arch/riscv/boards/litex-linux/lowlevel.c
> > @@ -0,0 +1,22 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +
> > +#include <common.h>
> > +#include <asm/barebox-riscv.h>
> > +#include <debug_ll.h>
> > +#include <asm/riscv_nmon.h>
> > +
> > +ENTRY_FUNCTION(start_litex_linux, a0, a1, a2)
> > +{
> > + extern char __dtb_z_litex_linux_start[];
> > + void *fdt;
> > +
> > + barebox_nmon_entry();
> > +
> > + putc_ll('>');
> > +
> > + /* On POR, we are running from read-only memory here. */
>
> Do we? I thought BIOS loads barebox to RAM first?
Yes, your are right. At the moment litex BIOS loads barebox to RAM first
and this comment must be dropped.
Please note there is a possibility to use barebox instead of litex BIOS
and start barebox on POR from ROM.
linux-on-litex-vexriscv bitstream for Arty board incorporates litex BIOS
so on Arty litex BIOS runs on POR unconditionally.
Litex BIOS is no more than 64K and "one does not simply push barebox into 64K".
But litex works on boards with tiny FPGA resources e.g. iCEBreaker-bitsy.
litex configuration for these tiny FPGA skips internal RAM/ROM and BIOS
starts from SPI flash so there is no limit on barebox image size.
>
> > +
> > + fdt = __dtb_z_litex_linux_start + get_runtime_offset();
> > +
> > + barebox_riscv_machine_entry(0x40000000, SZ_256M, fdt);
> > +}
> > diff --git a/arch/riscv/dts/Makefile b/arch/riscv/dts/Makefile
> > index 4a15423b7f..17d7d249e4 100644
> > --- a/arch/riscv/dts/Makefile
> > +++ b/arch/riscv/dts/Makefile
> > @@ -8,5 +8,6 @@ pbl-$(CONFIG_BOARD_ERIZO_GENERIC) += erizo-generic.dtb.o
> > pbl-$(CONFIG_BOARD_HIFIVE) += hifive-unmatched-a00.dtb.o \
> > hifive-unleashed-a00.dtb.o
> > pbl-$(CONFIG_BOARD_BEAGLEV) += jh7100-beaglev-starlight.dtb.o
> > +pbl-$(CONFIG_BOARD_LITEX_LINUX) += litex-linux.dtb.o
> >
> > clean-files := *.dtb *.dtb.S .*.dtc .*.pre .*.dts
> > diff --git a/arch/riscv/dts/litex-linux.dts b/arch/riscv/dts/litex-linux.dts
> > new file mode 100644
> > index 0000000000..d21fa57e30
> > --- /dev/null
> > +++ b/arch/riscv/dts/litex-linux.dts
> > @@ -0,0 +1,92 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +
> > +#include "litex_soc_linux.dtsi"
> > +
> > +#include <dt-bindings/gpio/gpio.h>
> > +
> > +/ {
> > + model = "LiteX VexRiscV-SoC-Linux";
> > + compatible = "litex,vexriscv-soc-linux";
> > +
> > + aliases {
> > + rom = &rom;
> > + sram = &sram;
> > + };
> > +
> > + /* ARTY board */
> > + rom: rom at 00000000 {
>
> I can see why RAM is specific to ARTY, but why ROM?
>
> > + compatible = "mmio-sram";
> > + reg = <0x00000000 0x00008000>;
> > + read-only;
> > + };
> > +
> > + sram: sram at 20000000 {
> > + compatible = "mmio-sram";
> > + reg = <0x20000000 0x00004000>;
> > + };
> > +
> > + main_ram: memory at 40000000 {
> > + device_type = "memory";
> > + reg = <0x40000000 0x10000000>;
> > + };
> > +};
> > +
> > +&uart0 {
> > + status = "okay";
> > +};
> > +
> > +&mac0 {
> > + status = "okay";
> > +};
> > +
> > +&spi0 {
> > + status = "okay";
> > +
> > + spiflash: w25q128 at 0 {
> > + #address-cells = <1>;
> > + #size-cells = <1>;
> > + compatible = "winbond,w25q128", "jedec,spi-nor";
> > + spi-max-frequency = <104000000>;
> > + reg = <0>;
> > + };
> > +};
> > +
> > +/ {
> > + ledsgpio: gpio at f000a800 {
> > + compatible = "ti,74175";
> > + reg = <0xf000a800 0x4>;
> > + gpio-controller;
> > + #gpio-cells = <2>;
> > + };
> > +
> > + leds {
> > + compatible = "gpio-leds";
> > +
> > + ld0 {
> > + label = "arty:green:ld0";
> > + gpios = <&ledsgpio 0 GPIO_ACTIVE_HIGH>;
> > + };
> > +
> > + ld1 {
> > + label = "arty:green:ld1";
> > + gpios = <&ledsgpio 1 GPIO_ACTIVE_HIGH>;
> > + };
> > +
> > + ld2 {
> > + label = "arty:green:ld2";
> > + gpios = <&ledsgpio 2 GPIO_ACTIVE_HIGH>;
> > + };
> > +
> > + ld3 {
> > + label = "arty:green:ld3";
> > + gpios = <&ledsgpio 3 GPIO_ACTIVE_HIGH>;
> > + };
> > + };
> > +
> > + swgpio: gpio at f0006000 {
> > + compatible = "ti,74125";
> > + reg = <0xf0006000 0x4>;
> > + gpio-controller;
> > + #gpio-cells = <2>;
> > + };
> > +};
> > diff --git a/arch/riscv/dts/litex_soc_linux.dtsi b/arch/riscv/dts/litex_soc_linux.dtsi
> > new file mode 100644
> > index 0000000000..94a0ba29da
> > --- /dev/null
> > +++ b/arch/riscv/dts/litex_soc_linux.dtsi
> > @@ -0,0 +1,49 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +
> > +/dts-v1/;
> > +
> > +/ {
> > + compatible = "litex,vexriscv-soc-linux";
> > +
> > + #address-cells = <1>;
> > + #size-cells = <1>;
> > +
> > + cpus {
> > + #address-cells = <1>;
> > + #size-cells = <0>;
> > +
> > + timebase-frequency = <100000000>; // 100 MHz
> > +
> > + cpu at 0 {
> > + device_type = "cpu";
> > + compatible = "spinalhdl,vexriscv", "riscv";
> > + reg = <0>;
> > + };
> > + };
> > +
> > + uart0: serial at f0001000 {
> > + compatible = "litex,uart";
> > + reg = <0xf0001000 0x18>;
> > + status = "disabled";
> > + };
> > +
> > + mac0: mac at f0006800 {
> > + compatible = "litex,liteeth";
> > + reg = <0xf0006800 0x7c /* base */
> > + 0xf0007000 0x0a /* mdio_base */
> > + 0xb0000000 0x2000>; /* buf_base */
> > + tx-fifo-depth = <2>;
> > + rx-fifo-depth = <2>;
> > + status = "disabled";
> > + };
> > +
> > + spi0: spi at f000b800 {
> > + compatible = "litex,spiflash";
> > +
> > + #address-cells = <1>;
> > + #size-cells = <0>;
> > +
> > + reg = <0xf000b800 0x100>;
> > + status = "disabled";
> > + };
> > +};
> > diff --git a/arch/riscv/include/asm/debug_ll.h b/arch/riscv/include/asm/debug_ll.h
> > index b4caa0597a..a3b9c1c4bc 100644
> > --- a/arch/riscv/include/asm/debug_ll.h
> > +++ b/arch/riscv/include/asm/debug_ll.h
> > @@ -43,6 +43,9 @@ static inline void PUTC_LL(char ch)
> >
> > writel(ch, uart0);
> > }
> > +#elif defined CONFIG_DEBUG_LITEX
> > +
> > +#include <asm/debug_ll_litex.h>
> >
> > #endif
> >
> > diff --git a/arch/riscv/include/asm/debug_ll_litex.h b/arch/riscv/include/asm/debug_ll_litex.h
> > new file mode 100644
> > index 0000000000..2fcdd9b0ec
> > --- /dev/null
> > +++ b/arch/riscv/include/asm/debug_ll_litex.h
> > @@ -0,0 +1,123 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only */
> > +/*
> > + * Copyright (C) 2019 Antony Pavlov <antonynpavlov at gmail.com>
> > + *
> > + * This file is part of barebox.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> > + * GNU General Public License for more details.
>
> Nitpick: That part could be dropped as the SPDX-License-Identifier
> above says as much.
ok.
>
> > + *
> > + */
> > +
> > +#ifndef __ASM_DEBUG_LL_LITEX__
> > +#define __ASM_DEBUG_LL_LITEX__
> > +
> > +/** @file
> > + * This File contains declaration for early output support
> > + */
> > +
> > +#include <linux/kconfig.h>
> > +
> > +#define DEBUG_LL_UART_ADDR 0xf0001000
> > +#define UART_RXTX 0x00
> > +#define UART_TXFULL 0x04
> > +#define UART_RXEMPTY 0x08
> > +#define UART_EV_PENDING 0x10
> > +#define UART_EV_RX (1 << 1)
> > +
> > +
> > +#ifndef __ASSEMBLY__
> > +
> > +/*
> > + * C macros
> > + */
> > +
> > +#include <asm/io.h>
> > +
> > +static inline void PUTC_LL(char ch)
> > +{
> > +#ifdef CONFIG_DEBUG_LL
> > + /* wait for space */
> > + while (__raw_readb((u8 *)DEBUG_LL_UART_ADDR + UART_TXFULL))
> > + ;
> > +
> > + __raw_writeb(ch, (u8 *)DEBUG_LL_UART_ADDR + UART_RXTX);
> > +#endif /* CONFIG_DEBUG_LL */
> > +}
> > +#else /* __ASSEMBLY__ */
> > +/*
> > + * Macros for use in assembly language code
> > + */
> > +
> > +/*
> > + * output a character in a0
> > + */
> > +.macro debug_ll_outc_a0
> > +#ifdef CONFIG_DEBUG_LL
> > +
> > + li t0, DEBUG_LL_UART_ADDR
> > +
> > +201:
> > + lbu t1, UART_TXFULL(t0) /* uart tx full ? */
> > + andi t1, t1, 0xff
> > + bnez t1, 201b /* try again */
> > +
> > + sb a0, UART_RXTX(t0) /* write the character */
> > +
> > +#endif /* CONFIG_DEBUG_LL */
> > +.endm
> > +
> > +/*
> > + * output a character
> > + */
> > +.macro debug_ll_outc chr
> > +#ifdef CONFIG_DEBUG_LL
> > + li a0, \chr
> > + debug_ll_outc_a0
> > +#endif /* CONFIG_DEBUG_LL */
> > +.endm
> > +
> > +/*
> > + * check character in input buffer
> > + * return value:
> > + * v0 = 0 no character in input buffer
> > + * v0 != 0 character in input buffer
> > + */
> > +.macro debug_ll_tstc
> > +#ifdef CONFIG_DEBUG_LL
> > + li t0, DEBUG_LL_UART_ADDR
> > +
> > + /* get line status and check for data present */
> > + lbu s0, UART_RXEMPTY(t0)
> > + bnez s0, 243f
> > + li s0, 1
> > + j 244f
> > +243: li s0, 0
> > +244: nop
> > +#endif /* CONFIG_DEBUG_LL */
> > +.endm
> > +
> > +/*
> > + * get character to v0
> > + */
> > +.macro debug_ll_getc
> > +#ifdef CONFIG_DEBUG_LL
> > +
> > +204:
> > + debug_ll_tstc
> > +
> > + /* try again */
> > + beqz s0, 204b
> > +
> > + /* read a character */
> > + lb s0, UART_RXTX(t0)
> > + li t1, UART_EV_RX
> > + sb t1, UART_EV_PENDING(t0)
> > +
> > +#endif /* CONFIG_DEBUG_LL */
> > +.endm
> > +#endif /* __ASSEMBLY__ */
> > +
> > +#endif /* __ASM_DEBUG_LL_LITEX__ */
> > diff --git a/common/Kconfig b/common/Kconfig
> > index a9feae2ae8..cb8bd8b2bf 100644
> > --- a/common/Kconfig
> > +++ b/common/Kconfig
> > @@ -1399,6 +1399,10 @@ config DEBUG_SIFIVE
> > bool "SiFive serial0 port"
> > depends on SOC_SIFIVE
> >
> > +config DEBUG_LITEX
> > + bool "LiteX serial port"
> > + depends on SOC_LITEX
> > +
> > endchoice
> >
> > config DEBUG_LL_NS16550
> > diff --git a/images/Makefile.riscv b/images/Makefile.riscv
> > index 4410765cf6..0645238c43 100644
> > --- a/images/Makefile.riscv
> > +++ b/images/Makefile.riscv
> > @@ -19,3 +19,7 @@ image-$(CONFIG_BOARD_HIFIVE) += barebox-hifive-unmatched.img barebox-hifive-unle
> > pblb-$(CONFIG_BOARD_BEAGLEV) += start_beaglev_starlight
> > FILE_barebox-beaglev-starlight.img = start_beaglev_starlight.pblb
> > image-$(CONFIG_BOARD_BEAGLEV) += barebox-beaglev-starlight.img
> > +
> > +pblb-$(CONFIG_BOARD_LITEX_LINUX) += start_litex_linux
> > +FILE_barebox-litex-linux.img = start_litex_linux.pblb
> > +image-$(CONFIG_BOARD_LITEX_LINUX) += barebox-litex-linux.img
> >
>
>
> --
> 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 |
--
Best regards,
Antony Pavlov
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