init.c

 1// SPDX-License-Identifier: GPL-2.0-only
 2/*
 3 * EcoNet setup code
 4 *
 5 * Copyright (C) 2025 Caleb James DeLisle <cjd@cjdns.fr>
 6 */
 7
 8#include <linux/init.h>
 9#include <linux/of_clk.h>
10#include <linux/irqchip.h>
11
12#include <asm/addrspace.h>
13#include <asm/io.h>
14#include <asm/bootinfo.h>
15#include <asm/time.h>
16#include <asm/prom.h>
17#include <asm/smp-ops.h>
18#include <asm/reboot.h>
19
20#define CR_AHB_RSTCR		((void __iomem *)CKSEG1ADDR(0x1fb00040))
21#define RESET			BIT(31)
22
23#define UART_BASE		CKSEG1ADDR(0x1fbf0003)
24#define UART_REG_SHIFT		2
25
26static void hw_reset(char *command)
27{
28	iowrite32(RESET, CR_AHB_RSTCR);
29}
30
31/* 1. Bring up early printk. */
32void __init prom_init(void)
33{
34	setup_8250_early_printk_port(UART_BASE, UART_REG_SHIFT, 0);
35	_machine_restart = hw_reset;
36}
37
38/* 2. Parse the DT and find memory */
39void __init plat_mem_setup(void)
40{
41	void *dtb;
42
43	set_io_port_base(KSEG1);
44
45	dtb = get_fdt();
46	if (!dtb)
47		panic("no dtb found");
48
49	__dt_setup_arch(dtb);
50
51	early_init_dt_scan_memory();
52}
53
54/* 3. Overload __weak device_tree_init(), add SMP_UP ops */
55void __init device_tree_init(void)
56{
57	unflatten_and_copy_device_tree();
58
59	register_up_smp_ops();
60}
61
62const char *get_system_type(void)
63{
64	return "EcoNet-EN75xx";
65}
66
67/* 4. Initialize the IRQ subsystem */
68void __init arch_init_irq(void)
69{
70	irqchip_init();
71}
72
73/* 5. Timers */
74void __init plat_time_init(void)
75{
76	of_clk_init(NULL);
77	timer_probe();
78}