/*
 * OMAP3-specific clock framework functions
 *
 * Copyright (C) 2007-2008 Texas Instruments, Inc.
 * Copyright (C) 2007-2009 Nokia Corporation
 *
 * Written by Paul Walmsley
 * Testing and integration fixes by Jouni Högander
 *
 * Parts of this code are based on code written by
 * Richard Woodruff, Tony Lindgren, Tuukka Tikkanen, Karthik Dasu
 *
 * 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.
 */
#undef DEBUG

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/limits.h>
#include <linux/bitops.h>

#include <plat/cpu.h>
#include <plat/clock.h>
#include <plat/sram.h>
#include <plat/sdrc.h>
#include <asm/div64.h>
#include <asm/clkdev.h>

#include "clock.h"
#include "clock34xx.h"
#include "sdrc.h"
#include "prm.h"
#include "prm-regbits-34xx.h"
#include "cm.h"
#include "cm-regbits-34xx.h"

/*
 * DPLL5_FREQ_FOR_USBHOST: USBHOST and USBTLL are the only clocks
 * that are sourced by DPLL5, and both of these require this clock
 * to be at 120 MHz for proper operation.
 */
#define DPLL5_FREQ_FOR_USBHOST		120000000

/* needed by omap3_core_dpll_m2_set_rate() */
struct clk *sdrc_ick_p, *arm_fck_p;

/**
 * omap3430es2_clk_ssi_find_idlest - return CM_IDLEST info for SSI
 * @clk: struct clk * being enabled
 * @idlest_reg: void __iomem ** to store CM_IDLEST reg address into
 * @idlest_bit: pointer to a u8 to store the CM_IDLEST bit shift into
 *
 * The OMAP3430ES2 SSI target CM_IDLEST bit is at a different shift
 * from the CM_{I,F}CLKEN bit.  Pass back the correct info via
 * @idlest_reg and @idlest_bit.  No return value.
 */
static void omap3430es2_clk_ssi_find_idlest(struct clk *clk,
					    void __iomem **idlest_reg,
					    u8 *idlest_bit)
{
	u32 r;

	r = (((__force u32)clk->enable_reg & ~0xf0) | 0x20);
	*idlest_reg = (__force void __iomem *)r;
	*idlest_bit = OMAP3430ES2_ST_SSI_IDLE_SHIFT;
}

const struct clkops clkops_omap3430es2_ssi_wait = {
	.enable		= omap2_dflt_clk_enable,
	.disable	= omap2_dflt_clk_disable,
	.find_idlest	= omap3430es2_clk_ssi_find_idlest,
	.find_companion = omap2_clk_dflt_find_companion,
};

/**
 * omap3430es2_clk_dss_usbhost_find_idlest - CM_IDLEST info for DSS, USBHOST
 * @clk: struct clk * being enabled
 * @idlest_reg: void __iomem ** to store CM_IDLEST reg address into
 * @idlest_bit: pointer to a u8 to store the CM_IDLEST bit shift into
 *
 * Some OMAP modules on OMAP3 ES2+ chips have both initiator and
 * target IDLEST bits.  For our purposes, we are concerned with the
 * target IDLEST bits, which exist at a different bit position than
 * the *CLKEN bit position for these modules (DSS and USBHOST) (The
 * default find_idlest code assumes that they are at the same
 * position.)  No return value.
 */
static void omap3430es2_clk_dss_usbhost_find_idlest(struct clk *clk,
						    void __iomem **idlest_reg,
						    u8 *idlest_bit)
{
	u32 r;

	r = (((__force u32)clk->enable_reg & ~0xf0) | 0x20);
	*idlest_reg = (__force void __iomem *)r;
	/* USBHOST_IDLE has same shift */
	*idlest_bit = OMAP3430ES2_ST_DSS_IDLE_SHIFT;
}

const struct clkops clkops_omap3430es2_dss_usbhost_wait = {
	.enable		= omap2_dflt_clk_enable,
	.disable	= omap2_dflt_clk_disable,
	.find_idlest	= omap3430es2_clk_dss_usbhost_find_idlest,
	.find_companion = omap2_clk_dflt_find_companion,
};

/**
 * omap3430es2_clk_hsotgusb_find_idlest - return CM_IDLEST info for HSOTGUSB
 * @clk: struct clk * being enabled
 * @idlest_reg: void __iomem ** to store CM_IDLEST reg address into
 * @idlest_bit: pointer to a u8 to store the CM_IDLEST bit shift into
 *
 * The OMAP3430ES2 HSOTGUSB target CM_IDLEST bit is at a different
 * shift from the CM_{I,F}CLKEN bit.  Pass back the correct info via
 * @idlest_reg and @idlest_bit.  No return value.
 */
static void omap3430es2_clk_hsotgusb_find_idlest(struct clk *clk,
						 void __iomem **idlest_reg,
						 u8 *idlest_bit)
{
	u32 r;

	r = (((__force u32)clk->enable_reg & ~0xf0) | 0x20);
	*idlest_reg = (__force void __iomem *)r;
	*idlest_bit = OMAP3430ES2_ST_HSOTGUSB_IDLE_SHIFT;
}

const struct clkops clkops_omap3430es2_hsotgusb_wait = {
	.enable		= omap2_dflt_clk_enable,
	.disable	= omap2_dflt_clk_disable,
	.find_idlest	= omap3430es2_clk_hsotgusb_find_idlest,
	.find_companion = omap2_clk_dflt_find_companion,
};

const struct clkops clkops_noncore_dpll_ops = {
	.enable		= omap3_noncore_dpll_enable,
	.disable	= omap3_noncore_dpll_disable,
};

int omap3_dpll4_set_rate(struct clk *clk, unsigned long rate)
{
	/*
	 * According to the 12-5 CDP code from TI, "Limitation 2.5"
	 * on 3430ES1 prevents us from changing DPLL multipliers or dividers
	 * on DPLL4.
	 */
	if (omap_rev() == OMAP3430_REV_ES1_0) {
		printk(KERN_ERR "clock: DPLL4 cannot change rate due to "
		       "silicon 'Limitation 2.5' on 3430ES1.\n");
		return -EINVAL;
	}
	return omap3_noncore_dpll_set_rate(clk, rate);
}

/* Common clock code */

/*
 * Set clocks for bypass mode for reboot to work.
 */
void omap2_clk_prepare_for_reboot(void)
{
	/* REVISIT: Not ready for 343x */
#if 0
	u32 rate;

	if (vclk == NULL || sclk == NULL)
		return;

	rate = clk_get_rate(sclk);
	clk_set_rate(vclk, rate);
#endif
}

void omap3_clk_lock_dpll5(void)
{
	struct clk *dpll5_clk;
	struct clk *dpll5_m2_clk;

	dpll5_clk = clk_get(NULL, "dpll5_ck");
	clk_set_rate(dpll5_clk, DPLL5_FREQ_FOR_USBHOST);
	clk_enable(dpll5_clk);

	/* Enable autoidle to allow it to enter low power bypass */
	omap3_dpll_allow_idle(dpll5_clk);

	/* Program dpll5_m2_clk divider for no division */
	dpll5_m2_clk = clk_get(NULL, "dpll5_m2_ck");
	clk_enable(dpll5_m2_clk);
	clk_set_rate(dpll5_m2_clk, DPLL5_FREQ_FOR_USBHOST);

	clk_disable(dpll5_m2_clk);
	clk_disable(dpll5_clk);
	return;
}

/* REVISIT: Move this init stuff out into clock.c */

/*
 * Switch the MPU rate if specified on cmdline.
 * We cannot do this early until cmdline is parsed.
 */
static int __init omap3xxx_clk_arch_init(void)
{
	struct clk *osc_sys_ck, *dpll1_ck, *arm_fck, *core_ck;
	unsigned long osc_sys_rate;

	if (!cpu_is_omap34xx())
		return 0;

	if (!mpurate)
		return -EINVAL;

	/* XXX test these for success */
	dpll1_ck = clk_get(NULL, "dpll1_ck");
	arm_fck = clk_get(NULL, "arm_fck");
	core_ck = clk_get(NULL, "core_ck");
	osc_sys_ck = clk_get(NULL, "osc_sys_ck");

	/* REVISIT: not yet ready for 343x */
	if (clk_set_rate(dpll1_ck, mpurate))
		printk(KERN_ERR "*** Unable to set MPU rate\n");

	recalculate_root_clocks();

	osc_sys_rate = clk_get_rate(osc_sys_ck);

	pr_info("Switched to new clocking rate (Crystal/Core/MPU): "
		"%ld.%01ld/%ld/%ld MHz\n",
		(osc_sys_rate / 1000000),
		((osc_sys_rate / 100000) % 10),
		(clk_get_rate(core_ck) / 1000000),
		(clk_get_rate(arm_fck) / 1000000));

	calibrate_delay();

	return 0;
}
arch_initcall(omap3xxx_clk_arch_init);