RISC-V: Init and Halt Code

This contains the various __init C functions, the initial assembly
kernel entry point, and the code to reset the system.  When a file was
init-related this patch contains the entire file.

Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>

1 files changed, 61 insertions, 0 deletions

diff --git a/arch/riscv/kernel/time.c b/arch/riscv/kernel/time.c
new file mode 100644
index 000000000000..2463fcca719e
--- /dev/null
+++ b/arch/riscv/kernel/time.c
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2012 Regents of the University of California
+ * Copyright (C) 2017 SiFive
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   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.
+ */
+
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/delay.h>
+
+#ifdef CONFIG_RISCV_TIMER
+#include <linux/timer_riscv.h>
+#endif
+
+#include <asm/sbi.h>
+
+unsigned long riscv_timebase;
+
+DECLARE_PER_CPU(struct clock_event_device, riscv_clock_event);
+
+void riscv_timer_interrupt(void)
+{
+#ifdef CONFIG_RISCV_TIMER
+	/*
+	 * FIXME: This needs to be cleaned up along with the rest of the IRQ
+	 * handling cleanup.  See irq.c for more details.
+	 */
+	struct clock_event_device *evdev = this_cpu_ptr(&riscv_clock_event);
+
+	evdev->event_handler(evdev);
+#endif
+}
+
+void __init init_clockevent(void)
+{
+	timer_probe();
+	csr_set(sie, SIE_STIE);
+}
+
+void __init time_init(void)
+{
+	struct device_node *cpu;
+	u32 prop;
+
+	cpu = of_find_node_by_path("/cpus");
+	if (!cpu || of_property_read_u32(cpu, "timebase-frequency", &prop))
+		panic(KERN_WARNING "RISC-V system with no 'timebase-frequency' in DTS\n");
+	riscv_timebase = prop;
+
+	lpj_fine = riscv_timebase / HZ;
+
+	init_clockevent();
+}