QEMU Virt on RISC-V has syscon-reboot and syscon-poweroff compatible
devices and describes them in the device tree. TinyEMU's Virt machine
is different and has a HTIF based poweroff and no dedicated reset
mechanism. Add board support for the HTIF poweroff and use a poor man's
reset that jumps back to the reset vector.
Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
---
arch/riscv/Kconfig.socs | 8 +++
arch/riscv/boards/Makefile | 1 +
arch/riscv/boards/riscvemu/Makefile | 1 +
arch/riscv/boards/riscvemu/board.c | 76 +++++++++++++++++++++++++++++
4 files changed, 86 insertions(+)
create mode 100644 arch/riscv/boards/riscvemu/Makefile
create mode 100644 arch/riscv/boards/riscvemu/board.c
diff --git a/arch/riscv/Kconfig.socs b/arch/riscv/Kconfig.socs
index 221ea133d4d0..1bd9b4d579d9 100644
--- a/arch/riscv/Kconfig.socs
+++ b/arch/riscv/Kconfig.socs
@@ -22,6 +22,14 @@ config SOC_VIRT
Generates an image tht can be be booted by QEMU. The image is called
barebox-dt-2nd.img
+config BOARD_RISCVEMU
+ depends on SOC_VIRT
+ bool "TinyEMU Virt Machine (riscvemu)"
+ default y
+ help
+ TinyEMU's Virt machine differs from QEMU in poweroff and restart
+ mechanisms. This adds the necessary support.
+
config CPU_SIFIVE
bool
select HAS_CACHE
diff --git a/arch/riscv/boards/Makefile b/arch/riscv/boards/Makefile
index cb28a25d8bc8..99630266d126 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_RISCVEMU) += riscvemu/
diff --git a/arch/riscv/boards/riscvemu/Makefile b/arch/riscv/boards/riscvemu/Makefile
new file mode 100644
index 000000000000..dcfc2937d325
--- /dev/null
+++ b/arch/riscv/boards/riscvemu/Makefile
@@ -0,0 +1 @@
+obj-y += board.o
diff --git a/arch/riscv/boards/riscvemu/board.c b/arch/riscv/boards/riscvemu/board.c
new file mode 100644
index 000000000000..7dbf9afe4c2d
--- /dev/null
+++ b/arch/riscv/boards/riscvemu/board.c
@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2021 Ahmad Fatoum, Pengutronix
+ */
+
+#include <common.h>
+#include <driver.h>
+#include <poweroff.h>
+#include <restart.h>
+#include <asm/system.h>
+#include <asm/barebox-riscv.h>
+
+struct riscvemu_priv {
+ struct restart_handler rst;
+ void __noreturn (*restart)(unsigned long, void *);
+
+};
+
+#define HTIF_BASE_ADDR IOMEM(0x40008000)
+#define HTIF_TOHOST_LOW (HTIF_BASE_ADDR + 0)
+#define HTIF_TOHOST_HIGH (HTIF_BASE_ADDR + 4)
+
+static void __noreturn riscvemu_poweroff(struct poweroff_handler *pwr)
+{
+ writel(1, HTIF_TOHOST_LOW);
+ writel(0, HTIF_TOHOST_HIGH);
+
+ __builtin_unreachable();
+}
+
+static void __noreturn riscvemu_restart(struct restart_handler *rst)
+{
+ struct riscvemu_priv *priv = container_of(rst, struct riscvemu_priv, rst);
+
+ /*
+ * barebox PBL relocates itself to end of RAM early on, so unless
+ * something explicitly scrubbed the initial PBL, we can jump back to
+ * the reset vector to "reset".
+ */
+ priv->restart(riscv_hartid(), barebox_riscv_boot_dtb());
+}
+
+static int riscvemu_probe(struct device_d *dev)
+{
+ struct device_node *of_chosen;
+ struct riscvemu_priv *priv;
+ u64 start;
+
+ if (of_find_compatible_node(NULL, NULL, "ucb,htif0"))
+ poweroff_handler_register_fn(riscvemu_poweroff);
+
+ of_chosen = of_find_node_by_path("/chosen");
+
+ if (of_property_read_u64(of_chosen, "riscv,kernel-start", &start))
+ return 0;
+
+ priv = xzalloc(sizeof(*priv));
+
+ priv->restart = (void *)(uintptr_t)start;
+ priv->rst.restart = riscvemu_restart;
+ priv->rst.name = "vector";
+
+ return restart_handler_register(&priv->rst);
+}
+
+static const struct of_device_id riscvemu_of_match[] = {
+ { .compatible = "ucbbar,riscvemu-bar_dev" },
+ { /* sentinel */ },
+};
+
+static struct driver_d riscvemu_board_driver = {
+ .name = "board-riscvemu",
+ .probe = riscvemu_probe,
+ .of_compatible = riscvemu_of_match,
+};
+device_platform_driver(riscvemu_board_driver);
--
2.30.2
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