shithub: riscv

ref: fe594760ebddac23e673d189d2152062ef75d8b8
dir: /sys/src/9/bcm/bootargs.c/

#include	"u.h"
#include	"../port/lib.h"
#include	"mem.h"
#include	"dat.h"
#include	"fns.h"

#define BOOTARGS	((char*)CONFADDR)
#define BOOTARGSLEN	((KZERO+REBOOTADDR)-CONFADDR)

#define	MAXCONF 64
static char *confname[MAXCONF];
static char *confval[MAXCONF];
static int nconf;

typedef struct Atag Atag;
struct Atag {
	u32int	size;	/* size of atag in words, including this header */
	u32int	tag;	/* atag type */
	union {
		u32int	data[1];	/* actually [size-2] */
		/* AtagMem */
		struct {
			u32int	size;
			u32int	base;
		} mem;
		/* AtagCmdLine */
		char	cmdline[1];	/* actually [4*(size-2)] */
	};
};

enum {
	AtagNone	= 0x00000000,
	AtagCore	= 0x54410001,
	AtagMem		= 0x54410002,
	AtagCmdline	= 0x54410009,
};

static int
findconf(char *k)
{
	int i;

	for(i = 0; i < nconf; i++)
		if(cistrcmp(confname[i], k) == 0)
			return i;
	return -1;
}

static void
addconf(char *k, char *v)
{
	int i;

	i = findconf(k);
	if(i < 0){
		if(nconf >= MAXCONF)
			return;
		i = nconf++;
		confname[i] = k;
	}
	confval[i] = v;
}

static void
plan9iniinit(char *s, int cmdline)
{
	char *toks[MAXCONF];
	int i, c, n;
	char *v;

	if((c = *s) < ' ' || c >= 0x80)
		return;
	if(cmdline)
		n = tokenize(s, toks, MAXCONF);
	else
		n = getfields(s, toks, MAXCONF, 1, "\n");
	for(i = 0; i < n; i++){
		if(toks[i][0] == '#')
			continue;
		v = strchr(toks[i], '=');
		if(v == nil)
			continue;
		*v++ = '\0';
		addconf(toks[i], v);
	}
}

void
bootargsinit(void)
{
	Atag *a;
	int n;

	a = (Atag*)BOOTARGS;
	if(a->tag != AtagCore){
		plan9iniinit((char*)a, 0);
		return;
	}
	while(a->tag != AtagNone && a->size != 0){
		switch(a->tag){
		case AtagMem:
			/* use only first bank */
			if(conf.mem[0].limit == 0 && a->mem.size != 0){
				memsize = a->mem.size;
				conf.mem[0].base = a->mem.base;
				conf.mem[0].limit = a->mem.base + memsize;
			}
			break;
		case AtagCmdline:
			n = (a->size * sizeof(u32int)) - offsetof(Atag, cmdline[0]);
			if(a->cmdline + n < BOOTARGS + BOOTARGSLEN)
				a->cmdline[n] = 0;
			else
				BOOTARGS[BOOTARGSLEN-1] = 0;
			plan9iniinit(a->cmdline, 1);
			break;
		}
		a = (Atag*)((u32int*)a + a->size);
	}
}

char*
getconf(char *name)
{
	int i;

	if((i = findconf(name)) < 0)
		return nil;
	return confval[i];
}

void
setconfenv(void)
{
	int i;

	for(i = 0; i < nconf; i++){
		if(confname[i][0] != '*')
			ksetenv(confname[i], confval[i], 0);
		ksetenv(confname[i], confval[i], 1);
	}
}

void
writeconf(void)
{
	char *p, *q;
	int n;

	p = getconfenv();
	if(waserror()) {
		free(p);
		nexterror();
	}

	/* convert to name=value\n format */
	for(q=p; *q; q++) {
		q += strlen(q);
		*q = '=';
		q += strlen(q);
		*q = '\n';
	}
	n = q - p + 1;
	if(n >= BOOTARGSLEN)
		error("kernel configuration too large");
	memmove(BOOTARGS, p, n);
	poperror();
	free(p);
}