[U-Boot] [PATCH 12/12] riscv: Add QEMU virt board support

[Bin Meng <bmeng.cn@gmail.com>]

This adds QEMU RISC-V 'virt' board target support, with the hope of
helping people easily test U-Boot on RISC-V.

The QEMU virt machine models a generic RISC-V virtual machine with
support for the VirtIO standard networking and block storage devices.
It has CLINT, PLIC, 16550A UART devices in addition to VirtIO and
it also uses device-tree to pass configuration information to guest
software. It implements RISC-V privileged architecture spec v1.10.

Both 32-bit and 64-bit builds are supported. Support is pretty much
preliminary, only booting to U-Boot shell with the UART driver on
a single core. Booting Linux is not supported yet.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>

---

 arch/riscv/Kconfig                      |  4 +++
 arch/riscv/cpu/qemu/Makefile            |  6 +++++
 arch/riscv/cpu/qemu/cpu.c               | 29 +++++++++++++++++++++
 arch/riscv/cpu/qemu/dram.c              | 17 ++++++++++++
 board/emulation/qemu-riscv/Kconfig      | 21 +++++++++++++++
 board/emulation/qemu-riscv/MAINTAINERS  |  7 +++++
 board/emulation/qemu-riscv/Makefile     |  5 ++++
 board/emulation/qemu-riscv/qemu-riscv.c | 23 +++++++++++++++++
 configs/qemu-riscv32_defconfig          | 10 +++++++
 configs/qemu-riscv64_defconfig          | 11 ++++++++
 doc/README.qemu-riscv                   | 46 +++++++++++++++++++++++++++++++++
 include/configs/qemu-riscv.h            | 21 +++++++++++++++
 12 files changed, 200 insertions(+)
 create mode 100644 arch/riscv/cpu/qemu/Makefile
 create mode 100644 arch/riscv/cpu/qemu/cpu.c
 create mode 100644 arch/riscv/cpu/qemu/dram.c
 create mode 100644 board/emulation/qemu-riscv/Kconfig
 create mode 100644 board/emulation/qemu-riscv/MAINTAINERS
 create mode 100644 board/emulation/qemu-riscv/Makefile
 create mode 100644 board/emulation/qemu-riscv/qemu-riscv.c
 create mode 100644 configs/qemu-riscv32_defconfig
 create mode 100644 configs/qemu-riscv64_defconfig
 create mode 100644 doc/README.qemu-riscv
 create mode 100644 include/configs/qemu-riscv.h

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 49f87de..168ca3d 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -11,9 +11,13 @@ choice
 config TARGET_AX25_AE350
 	bool "Support ax25-ae350"
 
+config TARGET_QEMU_VIRT
+	bool "Support QEMU Virt Board"
+
 endchoice
 
 source "board/AndesTech/ax25-ae350/Kconfig"
+source "board/emulation/qemu-riscv/Kconfig"
 
 choice
 	prompt "CPU selection"
diff --git a/arch/riscv/cpu/qemu/Makefile b/arch/riscv/cpu/qemu/Makefile
new file mode 100644
index 0000000..258e462
--- /dev/null
+++ b/arch/riscv/cpu/qemu/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+
+obj-y += dram.o
+obj-y += cpu.o
diff --git a/arch/riscv/cpu/qemu/cpu.c b/arch/riscv/cpu/qemu/cpu.c
new file mode 100644
index 0000000..a064639
--- /dev/null
+++ b/arch/riscv/cpu/qemu/cpu.c
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+ */
+
+#include <common.h>
+#include <command.h>
+
+/*
+ * cleanup_before_linux() is called just before we call linux
+ * it prepares the processor for linux
+ *
+ * we disable interrupt and caches.
+ */
+int cleanup_before_linux(void)
+{
+	disable_interrupts();
+
+	/* turn off I/D-cache */
+
+	return 0;
+}
+
+int do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	printf("reset unsupported yet\n");
+
+	return 0;
+}
diff --git a/arch/riscv/cpu/qemu/dram.c b/arch/riscv/cpu/qemu/dram.c
new file mode 100644
index 0000000..84d87d2
--- /dev/null
+++ b/arch/riscv/cpu/qemu/dram.c
@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+ */
+
+#include <common.h>
+#include <fdtdec.h>
+
+int dram_init(void)
+{
+	return fdtdec_setup_mem_size_base();
+}
+
+int dram_init_banksize(void)
+{
+	return fdtdec_setup_memory_banksize();
+}
diff --git a/board/emulation/qemu-riscv/Kconfig b/board/emulation/qemu-riscv/Kconfig
new file mode 100644
index 0000000..029f5efb
--- /dev/null
+++ b/board/emulation/qemu-riscv/Kconfig
@@ -0,0 +1,21 @@
+if TARGET_QEMU_VIRT
+
+config SYS_BOARD
+	default "qemu-riscv"
+
+config SYS_VENDOR
+	default "emulation"
+
+config SYS_CPU
+	default "qemu"
+
+config SYS_CONFIG_NAME
+	default "qemu-riscv"
+
+config SYS_TEXT_BASE
+	default 0x80000000
+
+config BOARD_SPECIFIC_OPTIONS # dummy
+	def_bool y
+
+endif
diff --git a/board/emulation/qemu-riscv/MAINTAINERS b/board/emulation/qemu-riscv/MAINTAINERS
new file mode 100644
index 0000000..3c6eb4f
--- /dev/null
+++ b/board/emulation/qemu-riscv/MAINTAINERS
@@ -0,0 +1,7 @@
+QEMU RISC-V 'VIRT' BOARD
+M:	Bin Meng <bmeng.cn@gmail.com>
+S:	Maintained
+F:	board/emulation/qemu-riscv/
+F:	include/configs/qemu-riscv.h
+F:	configs/qemu-riscv32_defconfig
+F:	configs/qemu-riscv64_defconfig
diff --git a/board/emulation/qemu-riscv/Makefile b/board/emulation/qemu-riscv/Makefile
new file mode 100644
index 0000000..3f29b90
--- /dev/null
+++ b/board/emulation/qemu-riscv/Makefile
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+
+obj-y	+= qemu-riscv.o
diff --git a/board/emulation/qemu-riscv/qemu-riscv.c b/board/emulation/qemu-riscv/qemu-riscv.c
new file mode 100644
index 0000000..041e716
--- /dev/null
+++ b/board/emulation/qemu-riscv/qemu-riscv.c
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+ */
+
+#include <common.h>
+#include <fdtdec.h>
+
+#define MROM_FDT_ADDR	0x1020
+
+int board_init(void)
+{
+	return 0;
+}
+
+void *board_fdt_blob_setup(void)
+{
+	/*
+	 * QEMU loads a generated DTB for us immediately
+	 * after the reset vectors in the MROM
+	 */
+	return (void *)MROM_FDT_ADDR;
+}
diff --git a/configs/qemu-riscv32_defconfig b/configs/qemu-riscv32_defconfig
new file mode 100644
index 0000000..cbd2c91
--- /dev/null
+++ b/configs/qemu-riscv32_defconfig
@@ -0,0 +1,10 @@
+CONFIG_RISCV=y
+CONFIG_TARGET_QEMU_VIRT=y
+CONFIG_NR_DRAM_BANKS=1
+CONFIG_BOOTDELAY=3
+CONFIG_DISPLAY_CPUINFO=y
+CONFIG_DISPLAY_BOARDINFO=y
+CONFIG_OF_BOARD=y
+CONFIG_DM_SERIAL=y
+CONFIG_SYS_NS16550=y
+CONFIG_TIMER=y
diff --git a/configs/qemu-riscv64_defconfig b/configs/qemu-riscv64_defconfig
new file mode 100644
index 0000000..af8b307
--- /dev/null
+++ b/configs/qemu-riscv64_defconfig
@@ -0,0 +1,11 @@
+CONFIG_RISCV=y
+CONFIG_TARGET_QEMU_VIRT=y
+CONFIG_CPU_RISCV_64=y
+CONFIG_NR_DRAM_BANKS=1
+CONFIG_BOOTDELAY=3
+CONFIG_DISPLAY_CPUINFO=y
+CONFIG_DISPLAY_BOARDINFO=y
+CONFIG_OF_BOARD=y
+CONFIG_DM_SERIAL=y
+CONFIG_SYS_NS16550=y
+CONFIG_TIMER=y
diff --git a/doc/README.qemu-riscv b/doc/README.qemu-riscv
new file mode 100644
index 0000000..e2e4804
--- /dev/null
+++ b/doc/README.qemu-riscv
@@ -0,0 +1,46 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+
+U-Boot on QEMU's 'virt' machine on RISC-V
+=========================================
+
+QEMU for RISC-V supports a special 'virt' machine designed for emulation and
+virtualization purposes. This document describes how to run U-Boot under it.
+Both 32-bit 64-bit targets are supported.
+
+The QEMU virt machine models a generic RISC-V virtual machine with support for
+the VirtIO standard networking and block storage devices. It has CLINT, PLIC,
+16550A UART devices in addition to VirtIO and it also uses device-tree to pass
+configuration information to guest software. It implements RISC-V privileged
+architecture spec v1.10.
+
+Building U-Boot
+---------------
+Set the CROSS_COMPILE environment variable as usual, and run:
+
+- For 32-bit RISC-V:
+    make qemu-riscv32_defconfig
+    make
+
+- For 64-bit RISC-V:
+    make qemu-riscv64_defconfig
+    make
+
+Running U-Boot
+--------------
+The minimal QEMU command line to get U-Boot up and running is:
+
+- For 32-bit RISC-V:
+    qemu-system-riscv32 -nographic -machine virt -kernel u-boot
+
+- For 64-bit RISC-V:
+    qemu-system-riscv64 -nographic -machine virt -kernel u-boot
+
+The commands above create targets with 128MiB memory by default.
+A freely configurable amount of RAM can be created via the '-m'
+parameter. For example, '-m 2G' creates 2GiB memory for the target,
+and the memory node in the embedded DTB created by QEMU reflects
+the new setting.
+
+These have been tested in QEMU 3.0.0.
diff --git a/include/configs/qemu-riscv.h b/include/configs/qemu-riscv.h
new file mode 100644
index 0000000..d279c23
--- /dev/null
+++ b/include/configs/qemu-riscv.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+ */
+
+#ifndef __CONFIG_H
+#define __CONFIG_H
+
+#include <linux/sizes.h>
+
+#define CONFIG_SYS_SDRAM_BASE		0x80000000
+#define CONFIG_SYS_INIT_SP_ADDR		(CONFIG_SYS_SDRAM_BASE + SZ_2M)
+
+#define CONFIG_SYS_LOAD_ADDR		(CONFIG_SYS_SDRAM_BASE + SZ_2M)
+
+#define CONFIG_SYS_MALLOC_LEN		SZ_8M
+
+/* Environment options */
+#define CONFIG_ENV_SIZE			SZ_4K
+
+#endif /* __CONFIG_H */
-- 
2.7.4