xref: /kernel/linux/linux-5.10/arch/mips/rb532/prom.c (revision 8c2ecf20) 
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *  RouterBoard 500 specific prom routines
4 *
5 *  Copyright (C) 2003, Peter Sadik <peter.sadik@idt.com>
6 *  Copyright (C) 2005-2006, P.Christeas <p_christ@hol.gr>
7 *  Copyright (C) 2007, Gabor Juhos <juhosg@openwrt.org>
8 *			Felix Fietkau <nbd@openwrt.org>
9 *			Florian Fainelli <florian@openwrt.org>
10 */
11
12#include <linux/init.h>
13#include <linux/mm.h>
14#include <linux/export.h>
15#include <linux/string.h>
16#include <linux/console.h>
17#include <linux/memblock.h>
18#include <linux/ioport.h>
19#include <linux/blkdev.h>
20
21#include <asm/bootinfo.h>
22#include <asm/mach-rc32434/ddr.h>
23#include <asm/mach-rc32434/prom.h>
24
25unsigned int idt_cpu_freq = 132000000;
26EXPORT_SYMBOL(idt_cpu_freq);
27
28static struct resource ddr_reg[] = {
29	{
30		.name = "ddr-reg",
31		.start = DDR0_PHYS_ADDR,
32		.end = DDR0_PHYS_ADDR + sizeof(struct ddr_ram),
33		.flags = IORESOURCE_MEM,
34	}
35};
36
37void __init prom_free_prom_memory(void)
38{
39	/* No prom memory to free */
40}
41
42static inline int match_tag(char *arg, const char *tag)
43{
44	return strncmp(arg, tag, strlen(tag)) == 0;
45}
46
47static inline unsigned long tag2ul(char *arg, const char *tag)
48{
49	char *num;
50
51	num = arg + strlen(tag);
52	return simple_strtoul(num, 0, 10);
53}
54
55void __init prom_setup_cmdline(void)
56{
57	static char cmd_line[COMMAND_LINE_SIZE] __initdata;
58	char *cp, *board;
59	int prom_argc;
60	char **prom_argv;
61	int i;
62
63	prom_argc = fw_arg0;
64	prom_argv = (char **) fw_arg1;
65
66	cp = cmd_line;
67		/* Note: it is common that parameters start
68		 * at argv[1] and not argv[0],
69		 * however, our elf loader starts at [0] */
70	for (i = 0; i < prom_argc; i++) {
71		if (match_tag(prom_argv[i], FREQ_TAG)) {
72			idt_cpu_freq = tag2ul(prom_argv[i], FREQ_TAG);
73			continue;
74		}
75#ifdef IGNORE_CMDLINE_MEM
76		/* parses out the "mem=xx" arg */
77		if (match_tag(prom_argv[i], MEM_TAG))
78			continue;
79#endif
80		if (i > 0)
81			*(cp++) = ' ';
82		if (match_tag(prom_argv[i], BOARD_TAG)) {
83			board = prom_argv[i] + strlen(BOARD_TAG);
84
85			if (match_tag(board, BOARD_RB532A))
86				mips_machtype = MACH_MIKROTIK_RB532A;
87			else
88				mips_machtype = MACH_MIKROTIK_RB532;
89		}
90
91		strcpy(cp, prom_argv[i]);
92		cp += strlen(prom_argv[i]);
93	}
94	*(cp++) = ' ';
95
96	i = strlen(arcs_cmdline);
97	if (i > 0) {
98		*(cp++) = ' ';
99		strcpy(cp, arcs_cmdline);
100		cp += strlen(arcs_cmdline);
101	}
102	cmd_line[COMMAND_LINE_SIZE - 1] = '\0';
103
104	strcpy(arcs_cmdline, cmd_line);
105}
106
107void __init prom_init(void)
108{
109	struct ddr_ram __iomem *ddr;
110	phys_addr_t memsize;
111	phys_addr_t ddrbase;
112
113	ddr = ioremap(ddr_reg[0].start,
114			ddr_reg[0].end - ddr_reg[0].start);
115
116	if (!ddr) {
117		printk(KERN_ERR "Unable to remap DDR register\n");
118		return;
119	}
120
121	ddrbase = (phys_addr_t)&ddr->ddrbase;
122	memsize = (phys_addr_t)&ddr->ddrmask;
123	memsize = 0 - memsize;
124
125	prom_setup_cmdline();
126
127	/* give all RAM to boot allocator,
128	 * except for the first 0x400 and the last 0x200 bytes */
129	memblock_add(ddrbase + 0x400, memsize - 0x600);
130}
131