[PATCH 7/9] RISC-V: add initial LiteX SoC support
Antony Pavlov
antonynpavlov at gmail.com
Wed May 5 03:08:58 PDT 2021
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 | 9 ++
arch/riscv/Makefile | 1 +
arch/riscv/dts/litex_soc_linux.dtsi | 49 +++++++
arch/riscv/mach-litex/Kconfig | 8 ++
arch/riscv/mach-litex/Makefile | 3 +
arch/riscv/mach-litex/include/mach/debug_ll.h | 124 ++++++++++++++++++
6 files changed, 194 insertions(+)
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index c0583f3153..40dfd7dd93 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -34,6 +34,14 @@ config MACH_ERIZO
select RISCV_M_MODE
select RISCV_TIMER
+config MACH_LITEX
+ bool "litex family"
+ select ARCH_RV32I
+ select HAS_DEBUG_LL
+ select HAS_NMON
+ select USE_COMPRESSED_DTB
+ select RISCV_SBI
+
config MACH_VIRT
bool "virt family"
select BOARD_RISCV_GENERIC_DT
@@ -83,6 +91,7 @@ config 64BIT
select PHYS_ADDR_T_64BIT
source "arch/riscv/mach-erizo/Kconfig"
+source "arch/riscv/mach-litex/Kconfig"
config BOARD_RISCV_GENERIC_DT
select BOARD_GENERIC_DT
diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index aba4526bba..bc22786368 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -20,6 +20,7 @@ cflags-y += $(riscv-cflags-y)
LDFLAGS_barebox += -nostdlib
machine-$(CONFIG_MACH_ERIZO) := erizo
+machine-$(CONFIG_MACH_LITEX) := litex
machine-$(CONFIG_MACH_VIRT) := virt
LDFLAGS_barebox += $(riscv-ldflags-y)
diff --git a/arch/riscv/dts/litex_soc_linux.dtsi b/arch/riscv/dts/litex_soc_linux.dtsi
new file mode 100644
index 0000000000..32382b8dc2
--- /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 f0009000 {
+ compatible = "litex,liteeth";
+ reg = <0xf0009000 0x7c /* base */
+ 0xf0009800 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/mach-litex/Kconfig b/arch/riscv/mach-litex/Kconfig
new file mode 100644
index 0000000000..19d5927e44
--- /dev/null
+++ b/arch/riscv/mach-litex/Kconfig
@@ -0,0 +1,8 @@
+if MACH_LITEX
+
+choice
+ prompt "Board type"
+
+endchoice
+
+endif
diff --git a/arch/riscv/mach-litex/Makefile b/arch/riscv/mach-litex/Makefile
new file mode 100644
index 0000000000..d9c51e74c3
--- /dev/null
+++ b/arch/riscv/mach-litex/Makefile
@@ -0,0 +1,3 @@
+# just to build a built-in.o. Otherwise compilation fails when no o-files is
+# created.
+obj- += dummy.o
diff --git a/arch/riscv/mach-litex/include/mach/debug_ll.h b/arch/riscv/mach-litex/include/mach/debug_ll.h
new file mode 100644
index 0000000000..df7032716d
--- /dev/null
+++ b/arch/riscv/mach-litex/include/mach/debug_ll.h
@@ -0,0 +1,124 @@
+/* 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.
+ *
+ */
+
+#ifndef __MACH_LITEX_DEBUG_LL__
+#define __MACH_LITEX_DEBUG_LL__
+
+/** @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)
+#define UART_EV_ENABLE 0x14
+
+
+#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 /* __MACH_LITEX_DEBUG_LL__ */
--
2.31.1
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