arch/arm/mach-omap2/cm.c

/*
 * OMAP2/3 CM module functions
 *
 * Copyright (C) 2009 Nokia Corporation
 * Paul Walmsley
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/io.h>

#include <asm/atomic.h>

#include "cm.h"
#include "cm-regbits-24xx.h"
#include "cm-regbits-34xx.h"

/* MAX_MODULE_READY_TIME: max milliseconds for module to leave idle */
#define MAX_MODULE_READY_TIME		20000

static const u8 cm_idlest_offs[] = {
	CM_IDLEST1, CM_IDLEST2, OMAP2430_CM_IDLEST3
};

/**
 * omap2_cm_wait_idlest_ready - wait for a module to leave idle or standby
 * @prcm_mod: PRCM module offset
 * @idlest_id: CM_IDLESTx register ID (i.e., x = 1, 2, 3)
 * @idlest_shift: shift of the bit in the CM_IDLEST* register to check
 *
 * XXX document
 */
int omap2_cm_wait_module_ready(s16 prcm_mod, u8 idlest_id, u8 idlest_shift)
{
	int ena = 0, i = 0;
	u8 cm_idlest_reg;
	u32 mask;

	if (!idlest_id || (idlest_id > ARRAY_SIZE(cm_idlest_offs)))
		return -EINVAL;

	cm_idlest_reg = cm_idlest_offs[idlest_id - 1];

	if (cpu_is_omap24xx())
		ena = idlest_shift;
	else if (cpu_is_omap34xx())
		ena = 0;
	else
		BUG();

	mask = 1 << idlest_shift;

	/* XXX should be OMAP2 CM */
	while (((cm_read_mod_reg(prcm_mod, cm_idlest_reg) & mask) != ena) &&
	       (i++ < MAX_MODULE_READY_TIME))
		udelay(1);

	return (i < MAX_MODULE_READY_TIME) ? 0 : -EBUSY;
}