code: 9ferno

ref: e81c54ba2ecc673a4d5f8aed0e9b52841fe07b0d
dir: /os/cerf405/gpio.c/

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

#define	GPIOREGS	((Gpioregs*)KADDR(PHYSGPIO))

static ulong gpioreserved;
static Lock gpiolock;

void
gpioreserve(ulong mask)
{
	ilock(&gpiolock);
	if(gpioreserved & mask)
		panic("gpioreserve: duplicate use of 0x%.8lux", gpioreserved & mask);
	gpioreserved |= mask;
	iunlock(&gpiolock);
}

/*
 * expand each of the bottom 16 bits into a two bit field
 * with the bit as low order bit in the field
 */
static ulong
inflate(ulong m)
{
	m  = ((m & 0xFF00) << 8) | (m & 0x00FF);
	m = ((m << 4) | m) & 0x0F0F0F0F;
	m = ((m << 2) | m) & 0x33333333;
	return ((m << 1) | m) & 0x55555555;
}

/*
 * set tcr, osr[hl], tsr[hl], odr, isr1[hl] for gpio bits in m,
 * following the configuration bits in cfg.  when setting
 * a gpio pin as output, set the right output value in OR first.
 */
void
gpioconfig(ulong m, ulong cfg)
{
	Gpioregs *g;
	ulong h, hm, l, lm;

	h = inflate(m>>16);
	hm = h | (h<<1);
	l = inflate(m);
	lm = l | (l<<1);
	ilock(&gpiolock);
	g = GPIOREGS;
	/*
	 * tsr has a setting ``Alt1 three-state source'' but
	 * table 23-7 sets it to zero (use TCR) and sets TCR.
 	 * thus, it seems never really to be needed.
	 */
	g->tsrh &= ~hm;
	g->tsrl &= ~lm;
	/* always select pin input (don't care for outputs) */
	g->isr1h = (g->isr1h & ~hm) | h;
	g->isr1l = (g->isr1l & ~lm) | l;
	if(cfg & Gpio_Alt1){	/* table 23-7 */
		g->osrh = (g->osrh & ~hm) | h;	/* alt1 source */
		g->osrl = (g->osrl & ~lm) | l;
	}else{
		g->osrh &= ~hm;	/* GPIO_OR source */
		g->osrl &= ~lm;
	}
	if(cfg & Gpio_OD)
		g->odr |= m;
	else
		g->odr &= ~m;
	if(cfg & Gpio_in || cfg & Gpio_Tri)
		g->tcr &= ~m;
	else
		g->tcr |= m;
	iunlock(&gpiolock);
}

ulong
gpioget(ulong mask)
{
	return GPIOREGS->ir & mask;
}

void
gpioset(ulong mask, ulong out)
{
	Gpioregs *g;

	ilock(&gpiolock);
	g = GPIOREGS;
	g->or = (g->or & ~mask) | (out & mask);
	iunlock(&gpiolock);
}

void
gpiorelease(ulong mask)
{
	ilock(&gpiolock);
	if((gpioreserved & mask) != mask)
		panic("gpiorelease: unexpected release of 0x%.8lux", ~gpioreserved & mask);
	gpioreserved &= ~mask;
	iunlock(&gpiolock);
}