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

#include "init.h"
#include <pool.h>

#include "reboot.h"

enum {
	/* space for syscall args, return PC, top-of-stack struct */
	Ustkheadroom	= sizeof(Sargs) + sizeof(uintptr) + sizeof(Tos),
};

/* Firmware compatibility */
#define	Minfirmrev	326770
#define	Minfirmdate	"19 Aug 2013"

/*
 * Where configuration info is left for the loaded programme.
 */
#define BOOTARGS	((char*)CONFADDR)
#define	BOOTARGSLEN	(MACHADDR-CONFADDR)
#define	MAXCONF		64
#define MAXCONFLINE	160

uintptr kseg0 = KZERO;
Mach*	machaddr[MAXMACH];
Conf	conf;
ulong	memsize = 128*1024*1024;

/*
 * Option arguments from the command line.
 * oargv[0] is the boot file.
 */
static int oargc;
static char* oargv[20];
static char oargb[128];
static int oargblen;

static uintptr sp;		/* XXX - must go - user stack of init proc */

/* store plan9.ini contents here at least until we stash them in #ec */
static char confname[MAXCONF][KNAMELEN];
static char confval[MAXCONF][MAXCONFLINE];
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 *name)
{
	int i;

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

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

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

void
addconf(char *name, char *val)
{
	int i;

	i = findconf(name);
	if(i < 0){
		if(val == nil || nconf >= MAXCONF)
			return;
		i = nconf++;
		strecpy(confname[i], confname[i]+sizeof(confname[i]), name);
	}
	strecpy(confval[i], confval[i]+sizeof(confval[i]), val);
}

static 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);
	memset(BOOTARGS + n, '\n', BOOTARGSLEN - n);
	poperror();
	free(p);
}

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);
	}
}

static void
ataginit(Atag *a)
{
	int n;

	if(a->tag != AtagCore){
		plan9iniinit((char*)a, 0);
		return;
	}
	while(a->tag != AtagNone){
		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);
	}
}

void
machinit(void)
{
	m->machno = 0;
	machaddr[m->machno] = m;

	m->ticks = 1;
	m->perf.period = 1;

	conf.nmach = 1;

	active.machs = 1;
	active.exiting = 0;

	up = nil;
}

static void
optionsinit(char* s)
{
	strecpy(oargb, oargb+sizeof(oargb), s);

	oargblen = strlen(oargb);
	oargc = tokenize(oargb, oargv, nelem(oargv)-1);
	oargv[oargc] = nil;
}

void
main(void)
{
	extern char edata[], end[];
	uint rev;

	okay(1);
	m = (Mach*)MACHADDR;
	memset(edata, 0, end - edata);	/* clear bss */
	machinit();
	mmuinit1();

	optionsinit("/boot/boot boot");
	quotefmtinstall();
	
	ataginit((Atag*)BOOTARGS);
	confinit();		/* figures out amount of memory */
	xinit();
	uartconsinit();
	screeninit();

	print("\nPlan 9 from Bell Labs\n");
	rev = getfirmware();
	print("firmware: rev %d\n", rev);
	if(rev < Minfirmrev){
		print("Sorry, firmware (start*.elf) must be at least rev %d"
		      " or newer than %s\n", Minfirmrev, Minfirmdate);
		for(;;)
			;
	}
	trapinit();
	clockinit();
	printinit();
	timersinit();
	if(conf.monitor)
		swcursorinit();
	cpuidprint();
	archreset();

	procinit0();
	initseg();
	links();
	chandevreset();			/* most devices are discovered here */
	pageinit();
	swapinit();
	userinit();
	schedinit();
	assert(0);			/* shouldn't have returned */
}

/*
 *  starting place for first process
 */
void
init0(void)
{
	int i;
	char buf[2*KNAMELEN];

	up->nerrlab = 0;
	coherence();
	spllo();

	/*
	 * These are o.k. because rootinit is null.
	 * Then early kproc's will have a root and dot.
	 */
	up->slash = namec("#/", Atodir, 0, 0);
	pathclose(up->slash->path);
	up->slash->path = newpath("/");
	up->dot = cclone(up->slash);

	chandevinit();

	if(!waserror()){
		snprint(buf, sizeof(buf), "%s %s", "ARM", conffile);
		ksetenv("terminal", buf, 0);
		ksetenv("cputype", "arm", 0);
		if(cpuserver)
			ksetenv("service", "cpu", 0);
		else
			ksetenv("service", "terminal", 0);
		snprint(buf, sizeof(buf), "-a %s", getethermac());
		ksetenv("etherargs", buf, 0);

		/* convert plan9.ini variables to #e and #ec */
		for(i = 0; i < nconf; i++) {
			ksetenv(confname[i], confval[i], 0);
			ksetenv(confname[i], confval[i], 1);
		}
		poperror();
	}
	kproc("alarm", alarmkproc, 0);
	touser(sp);
	assert(0);			/* shouldn't have returned */
}

static void
bootargs(uintptr base)
{
	int i;
	ulong ssize;
	char **av, *p;

	/*
	 * Push the boot args onto the stack.
	 * The initial value of the user stack must be such
	 * that the total used is larger than the maximum size
	 * of the argument list checked in syscall.
	 */
	i = oargblen+1;
	p = UINT2PTR(STACKALIGN(base + BY2PG - Ustkheadroom - i));
	memmove(p, oargb, i);

	/*
	 * Now push the argv pointers.
	 * The code jumped to by touser in lproc.s expects arguments
	 *	main(char* argv0, ...)
	 * and calls
	 * 	startboot("/boot/boot", &argv0)
	 * not the usual (int argc, char* argv[])
	 */
	av = (char**)(p - (oargc+1)*sizeof(char*));
	ssize = base + BY2PG - PTR2UINT(av);
	for(i = 0; i < oargc; i++)
		*av++ = (oargv[i] - oargb) + (p - base) + (USTKTOP - BY2PG);
	*av = nil;
	sp = USTKTOP - ssize;
}

/*
 *  create the first process
 */
void
userinit(void)
{
	Proc *p;
	Segment *s;
	KMap *k;
	Page *pg;

	/* no processes yet */
	up = nil;

	p = newproc();
	p->pgrp = newpgrp();
	p->egrp = smalloc(sizeof(Egrp));
	p->egrp->ref = 1;
	p->fgrp = dupfgrp(nil);
	p->rgrp = newrgrp();
	p->procmode = 0640;

	kstrdup(&eve, "");
	kstrdup(&p->text, "*init*");
	kstrdup(&p->user, eve);

	/*
	 * Kernel Stack
	 */
	p->sched.pc = PTR2UINT(init0);
	p->sched.sp = PTR2UINT(p->kstack+KSTACK-sizeof(up->s.args)-sizeof(uintptr));
	p->sched.sp = STACKALIGN(p->sched.sp);

	/*
	 * User Stack
	 *
	 * Technically, newpage can't be called here because it
	 * should only be called when in a user context as it may
	 * try to sleep if there are no pages available, but that
	 * shouldn't be the case here.
	 */
	s = newseg(SG_STACK, USTKTOP-USTKSIZE, USTKSIZE/BY2PG);
	s->flushme++;
	p->seg[SSEG] = s;
	pg = newpage(1, 0, USTKTOP-BY2PG);
	segpage(s, pg);
	k = kmap(pg);
	bootargs(VA(k));
	kunmap(k);

	/*
	 * Text
	 */
	s = newseg(SG_TEXT, UTZERO, 1);
	p->seg[TSEG] = s;
	pg = newpage(1, 0, UTZERO);
	memset(pg->cachectl, PG_TXTFLUSH, sizeof(pg->cachectl));
	segpage(s, pg);
	k = kmap(s->map[0]->pages[0]);
	memmove(UINT2PTR(VA(k)), initcode, sizeof initcode);
	kunmap(k);

	ready(p);
}

void
confinit(void)
{
	int i;
	ulong kpages;
	uintptr pa;
	char *p;

	if(0 && (p = getconf("service")) != nil){
		if(strcmp(p, "cpu") == 0)
			cpuserver = 1;
		else if(strcmp(p,"terminal") == 0)
			cpuserver = 0;
	}
	if((p = getconf("*maxmem")) != nil){
		memsize = strtoul(p, 0, 0) - PHYSDRAM;
		if (memsize < 16*MB)		/* sanity */
			memsize = 16*MB;
	}

	getramsize(&conf.mem[0]);
	if(conf.mem[0].limit == 0){
		conf.mem[0].base = PHYSDRAM;
		conf.mem[0].limit = PHYSDRAM + memsize;
	}else if(p != nil)
		conf.mem[0].limit = conf.mem[0].base + memsize;

	conf.npage = 0;
	pa = PADDR(PGROUND(PTR2UINT(end)));

	/*
	 *  we assume that the kernel is at the beginning of one of the
	 *  contiguous chunks of memory and fits therein.
	 */
	for(i=0; i<nelem(conf.mem); i++){
		/* take kernel out of allocatable space */
		if(pa > conf.mem[i].base && pa < conf.mem[i].limit)
			conf.mem[i].base = pa;

		conf.mem[i].npage = (conf.mem[i].limit - conf.mem[i].base)/BY2PG;
		conf.npage += conf.mem[i].npage;
	}

	conf.upages = (conf.npage*80)/100;
	conf.ialloc = ((conf.npage-conf.upages)/2)*BY2PG;

	/* only one processor */
	conf.nmach = 1;

	/* set up other configuration parameters */
	conf.nproc = 100 + ((conf.npage*BY2PG)/MB)*5;
	if(cpuserver)
		conf.nproc *= 3;
	if(conf.nproc > 2000)
		conf.nproc = 2000;
	conf.nswap = conf.npage*3;
	conf.nswppo = 4096;
	conf.nimage = 200;

	conf.copymode = 0;		/* copy on write */

	/*
	 * Guess how much is taken by the large permanent
	 * datastructures. Mntcache and Mntrpc are not accounted for
	 * (probably ~300KB).
	 */
	kpages = conf.npage - conf.upages;
	kpages *= BY2PG;
	kpages -= conf.upages*sizeof(Page)
		+ conf.nproc*sizeof(Proc)
		+ conf.nimage*sizeof(Image)
		+ conf.nswap
		+ conf.nswppo*sizeof(Page);
	mainmem->maxsize = kpages;
	if(!cpuserver)
		/*
		 * give terminals lots of image memory, too; the dynamic
		 * allocation will balance the load properly, hopefully.
		 * be careful with 32-bit overflow.
		 */
		imagmem->maxsize = kpages;

}

static void
shutdown(int ispanic)
{
	int ms, once;

	lock(&active);
	if(ispanic)
		active.ispanic = ispanic;
	else if(m->machno == 0 && (active.machs & (1<<m->machno)) == 0)
		active.ispanic = 0;
	once = active.machs & (1<<m->machno);
	active.machs &= ~(1<<m->machno);
	active.exiting = 1;
	unlock(&active);

	if(once)
		iprint("cpu%d: exiting\n", m->machno);
	spllo();
	for(ms = 5*1000; ms > 0; ms -= TK2MS(2)){
		delay(TK2MS(2));
		if(active.machs == 0 && consactive() == 0)
			break;
	}
	delay(1000);
}

/*
 *  exit kernel either on a panic or user request
 */
void
exit(int code)
{
	shutdown(code);
	splfhi();
	archreboot();
}

/*
 * stub for ../omap/devether.c
 */
int
isaconfig(char *class, int ctlrno, ISAConf *isa)
{
	USED(ctlrno);
	USED(isa);
	return strcmp(class, "ether") == 0;
}

/*
 * the new kernel is already loaded at address `code'
 * of size `size' and entry point `entry'.
 */
void
reboot(void *entry, void *code, ulong size)
{
	void (*f)(ulong, ulong, ulong);

	print("starting reboot...");
	writeconf();
	shutdown(0);

	/*
	 * should be the only processor running now
	 */

	print("reboot entry %#lux code %#lux size %ld\n",
		PADDR(entry), PADDR(code), size);
	delay(100);

	/* turn off buffered serial console */
	serialoq = nil;
	kprintoq = nil;
	screenputs = nil;

	/* shutdown devices */
	chandevshutdown();

	/* stop the clock (and watchdog if any) */
	clockshutdown();

	splfhi();
	intrsoff();

	/* setup reboot trampoline function */
	f = (void*)REBOOTADDR;
	memmove(f, rebootcode, sizeof(rebootcode));
	cacheuwbinv();

	/* off we go - never to return */
	(*f)(PADDR(entry), PADDR(code), size);

	iprint("loaded kernel returned!\n");
	delay(1000);
	archreboot();
}

int
cmpswap(long *addr, long old, long new)
{
	return cas32(addr, old, new);
}