prom.c

  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
 20#include <asm/bootinfo.h>
 21#include <asm/mach-rc32434/ddr.h>
 22#include <asm/mach-rc32434/prom.h>
 23
 24unsigned int idt_cpu_freq = 132000000;
 25EXPORT_SYMBOL(idt_cpu_freq);
 26
 27static struct resource ddr_reg[] = {
 28	{
 29		.name = "ddr-reg",
 30		.start = DDR0_PHYS_ADDR,
 31		.end = DDR0_PHYS_ADDR + sizeof(struct ddr_ram),
 32		.flags = IORESOURCE_MEM,
 33	}
 34};
 35
 36static inline int match_tag(char *arg, const char *tag)
 37{
 38	return strncmp(arg, tag, strlen(tag)) == 0;
 39}
 40
 41static inline unsigned long tag2ul(char *arg, const char *tag)
 42{
 43	char *num;
 44
 45	num = arg + strlen(tag);
 46	return simple_strtoul(num, 0, 10);
 47}
 48
 49static void __init prom_setup_cmdline(void)
 50{
 51	static char cmd_line[COMMAND_LINE_SIZE] __initdata;
 52	char *cp, *board;
 53	int prom_argc;
 54	char **prom_argv;
 55	int i;
 56	size_t len;
 57
 58	prom_argc = fw_arg0;
 59	prom_argv = (char **) fw_arg1;
 60
 61	cp = cmd_line;
 62		/* Note: it is common that parameters start
 63		 * at argv[1] and not argv[0],
 64		 * however, our elf loader starts at [0] */
 65	for (i = 0; i < prom_argc; i++) {
 66		if (match_tag(prom_argv[i], FREQ_TAG)) {
 67			idt_cpu_freq = tag2ul(prom_argv[i], FREQ_TAG);
 68			continue;
 69		}
 70#ifdef IGNORE_CMDLINE_MEM
 71		/* parses out the "mem=xx" arg */
 72		if (match_tag(prom_argv[i], MEM_TAG))
 73			continue;
 74#endif
 75		if (i > 0)
 76			*(cp++) = ' ';
 77		if (match_tag(prom_argv[i], BOARD_TAG)) {
 78			board = prom_argv[i] + strlen(BOARD_TAG);
 79
 80			if (match_tag(board, BOARD_RB532A))
 81				mips_machtype = MACH_MIKROTIK_RB532A;
 82			else
 83				mips_machtype = MACH_MIKROTIK_RB532;
 84		}
 85
 86		len = strlen(prom_argv[i]);
 87		memcpy(cp, prom_argv[i], len + 1);
 88		cp += len;
 89	}
 90	*(cp++) = ' ';
 91
 92	len = strlen(arcs_cmdline);
 93	if (len > 0) {
 94		*(cp++) = ' ';
 95		memcpy(cp, arcs_cmdline, len + 1);
 96		cp += len;
 97	}
 98	cmd_line[COMMAND_LINE_SIZE - 1] = '\0';
 99	strscpy(arcs_cmdline, cmd_line);
100}
101
102void __init prom_init(void)
103{
104	struct ddr_ram __iomem *ddr;
105	phys_addr_t memsize;
106	phys_addr_t ddrbase;
107
108	ddr = ioremap(ddr_reg[0].start,
109			ddr_reg[0].end - ddr_reg[0].start);
110
111	if (!ddr) {
112		printk(KERN_ERR "Unable to remap DDR register\n");
113		return;
114	}
115
116	ddrbase = (phys_addr_t)&ddr->ddrbase;
117	memsize = (phys_addr_t)&ddr->ddrmask;
118	memsize = 0 - memsize;
119
120	prom_setup_cmdline();
121
122	/* give all RAM to boot allocator,
123	 * except for the first 0x400 and the last 0x200 bytes */
124	memblock_add(ddrbase + 0x400, memsize - 0x600);
125}