/* Copyright (c) 2010-2013, The Linux Foundation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#include <linux/err.h>
#include <linux/mutex.h>
#include <mach/clk-provider.h>

#include "rpm_resources.h"
#include "clock-rpm.h"

#define __clk_rpmrs_set_rate(r, value, ctx) \
	((r)->rpmrs_data->set_rate_fn((r), (value), (ctx)))

#define clk_rpmrs_set_rate_sleep(r, value) \
	    __clk_rpmrs_set_rate((r), (value), (r)->rpmrs_data->ctx_sleep_id)

#define clk_rpmrs_set_rate_active(r, value) \
	   __clk_rpmrs_set_rate((r), (value), (r)->rpmrs_data->ctx_active_id)

static int clk_rpmrs_set_rate(struct rpm_clk *r, uint32_t value,
			   uint32_t context)
{
	struct msm_rpm_iv_pair iv = {
		.id = r->rpm_clk_id,
		.value = value,
	};
	return msm_rpmrs_set(context, &iv, 1);
}

static int clk_rpmrs_get_rate(struct rpm_clk *r)
{
	int rc;
	struct msm_rpm_iv_pair iv = { .id = r->rpm_status_id, };
	rc = msm_rpm_get_status(&iv, 1);
	return (rc < 0) ? rc : iv.value * r->factor;
}

static int clk_rpmrs_handoff(struct rpm_clk *r)
{
	struct msm_rpm_iv_pair iv = { .id = r->rpm_status_id, };
	int rc = msm_rpm_get_status(&iv, 1);

	if (rc < 0)
		return rc;

	if (!r->branch)
		r->c.rate = iv.value * r->factor;

	return 0;
}

static int clk_rpmrs_set_rate_smd(struct rpm_clk *r, uint32_t value,
				uint32_t context)
{
	struct msm_rpm_kvp kvp = {
		.key = r->rpm_key,
		.data = (void *)&value,
		.length = sizeof(value),
	};

	return msm_rpm_send_message(context, r->rpm_res_type, r->rpm_clk_id,
			&kvp, 1);
}

static int clk_rpmrs_handoff_smd(struct rpm_clk *r)
{
	if (!r->branch)
		r->c.rate = INT_MAX;

	return 0;
}

struct clk_rpmrs_data {
	int (*set_rate_fn)(struct rpm_clk *r, uint32_t value, uint32_t context);
	int (*get_rate_fn)(struct rpm_clk *r);
	int (*handoff_fn)(struct rpm_clk *r);
	int ctx_active_id;
	int ctx_sleep_id;
};

struct clk_rpmrs_data clk_rpmrs_data = {
	.set_rate_fn = clk_rpmrs_set_rate,
	.get_rate_fn = clk_rpmrs_get_rate,
	.handoff_fn = clk_rpmrs_handoff,
	.ctx_active_id = MSM_RPM_CTX_SET_0,
	.ctx_sleep_id = MSM_RPM_CTX_SET_SLEEP,
};

struct clk_rpmrs_data clk_rpmrs_data_smd = {
	.set_rate_fn = clk_rpmrs_set_rate_smd,
	.handoff_fn = clk_rpmrs_handoff_smd,
	.ctx_active_id = MSM_RPM_CTX_ACTIVE_SET,
	.ctx_sleep_id = MSM_RPM_CTX_SLEEP_SET,
};

static DEFINE_MUTEX(rpm_clock_lock);

static void to_active_sleep_khz(struct rpm_clk *r, unsigned long rate,
			unsigned long *active_khz, unsigned long *sleep_khz)
{
	/* Convert the rate (hz) to khz */
	*active_khz = DIV_ROUND_UP(rate, r->factor);

	/*
	 * Active-only clocks don't care what the rate is during sleep. So,
	 * they vote for zero.
	 */
	if (r->active_only)
		*sleep_khz = 0;
	else
		*sleep_khz = *active_khz;
}

static int rpm_clk_prepare(struct clk *clk)
{
	struct rpm_clk *r = to_rpm_clk(clk);
	uint32_t value;
	int rc = 0;
	unsigned long this_khz, this_sleep_khz;
	unsigned long peer_khz = 0, peer_sleep_khz = 0;
	struct rpm_clk *peer = r->peer;

	mutex_lock(&rpm_clock_lock);

	to_active_sleep_khz(r, r->c.rate, &this_khz, &this_sleep_khz);

	/* Don't send requests to the RPM if the rate has not been set. */
	if (this_khz == 0)
		goto out;

	/* Take peer clock's rate into account only if it's enabled. */
	if (peer->enabled)
		to_active_sleep_khz(peer, peer->c.rate,
				&peer_khz, &peer_sleep_khz);

	value = max(this_khz, peer_khz);
	if (r->branch)
		value = !!value;

	rc = clk_rpmrs_set_rate_active(r, value);
	if (rc)
		goto out;

	value = max(this_sleep_khz, peer_sleep_khz);
	if (r->branch)
		value = !!value;

	rc = clk_rpmrs_set_rate_sleep(r, value);
	if (rc) {
		/* Undo the active set vote and restore it to peer_khz */
		value = peer_khz;
		rc = clk_rpmrs_set_rate_active(r, value);
	}

out:
	if (!rc)
		r->enabled = true;

	mutex_unlock(&rpm_clock_lock);

	return rc;
}

static void rpm_clk_unprepare(struct clk *clk)
{
	struct rpm_clk *r = to_rpm_clk(clk);

	mutex_lock(&rpm_clock_lock);

	if (r->c.rate) {
		uint32_t value;
		struct rpm_clk *peer = r->peer;
		unsigned long peer_khz = 0, peer_sleep_khz = 0;
		int rc;

		/* Take peer clock's rate into account only if it's enabled. */
		if (peer->enabled)
			to_active_sleep_khz(peer, peer->c.rate,
				&peer_khz, &peer_sleep_khz);

		value = r->branch ? !!peer_khz : peer_khz;
		rc = clk_rpmrs_set_rate_active(r, value);
		if (rc)
			goto out;

		value = r->branch ? !!peer_sleep_khz : peer_sleep_khz;
		rc = clk_rpmrs_set_rate_sleep(r, value);
	}
	r->enabled = false;
out:
	mutex_unlock(&rpm_clock_lock);

	return;
}

static int rpm_clk_set_rate(struct clk *clk, unsigned long rate)
{
	struct rpm_clk *r = to_rpm_clk(clk);
	unsigned long this_khz, this_sleep_khz;
	int rc = 0;

	mutex_lock(&rpm_clock_lock);

	if (r->enabled) {
		uint32_t value;
		struct rpm_clk *peer = r->peer;
		unsigned long peer_khz = 0, peer_sleep_khz = 0;

		to_active_sleep_khz(r, rate, &this_khz, &this_sleep_khz);

		/* Take peer clock's rate into account only if it's enabled. */
		if (peer->enabled)
			to_active_sleep_khz(peer, peer->c.rate,
					&peer_khz, &peer_sleep_khz);

		value = max(this_khz, peer_khz);
		rc = clk_rpmrs_set_rate_active(r, value);
		if (rc)
			goto out;

		value = max(this_sleep_khz, peer_sleep_khz);
		rc = clk_rpmrs_set_rate_sleep(r, value);
	}

out:
	mutex_unlock(&rpm_clock_lock);

	return rc;
}

static int rpm_branch_clk_set_rate(struct clk *clk, unsigned long rate)
{
	if (rate == clk->rate)
		return 0;

	return -EPERM;
}

static unsigned long rpm_clk_get_rate(struct clk *clk)
{
	struct rpm_clk *r = to_rpm_clk(clk);
	if (r->rpmrs_data->get_rate_fn)
		return r->rpmrs_data->get_rate_fn(r);
	else
		return clk->rate;
}

static int rpm_clk_is_enabled(struct clk *clk)
{
	return !!(rpm_clk_get_rate(clk));
}

static long rpm_clk_round_rate(struct clk *clk, unsigned long rate)
{
	/* Not supported. */
	return rate;
}

static bool rpm_clk_is_local(struct clk *clk)
{
	return false;
}

static enum handoff rpm_clk_handoff(struct clk *clk)
{
	struct rpm_clk *r = to_rpm_clk(clk);
	int rc;

	/*
	 * Querying an RPM clock's status will return 0 unless the clock's
	 * rate has previously been set through the RPM. When handing off,
	 * assume these clocks are enabled (unless the RPM call fails) so
	 * child clocks of these RPM clocks can still be handed off.
	 */
	rc  = r->rpmrs_data->handoff_fn(r);
	if (rc < 0)
		return HANDOFF_DISABLED_CLK;

	/*
	 * Since RPM handoff code may update the software rate of the clock by
	 * querying the RPM, we need to make sure our request to RPM now
	 * matches the software rate of the clock. When we send the request
	 * to RPM, we also need to update any other state info we would
	 * normally update. So, call the appropriate clock function instead
	 * of directly using the RPM driver APIs.
	 */
	rc = rpm_clk_prepare(clk);
	if (rc < 0)
		return HANDOFF_DISABLED_CLK;

	return HANDOFF_ENABLED_CLK;
}

#define RPM_MISC_CLK_TYPE	0x306b6c63
#define RPM_SCALING_ENABLE_ID	0x2

void enable_rpm_scaling(void)
{
	int rc, value = 0x1;
	struct msm_rpm_kvp kvp = {
		.key = RPM_SMD_KEY_ENABLE,
		.data = (void *)&value,
		.length = sizeof(value),
	};

	rc = msm_rpm_send_message_noirq(MSM_RPM_CTX_SLEEP_SET,
			RPM_MISC_CLK_TYPE, RPM_SCALING_ENABLE_ID, &kvp, 1);
	WARN(rc < 0, "RPM clock scaling (sleep set) did not enable!\n");

	rc = msm_rpm_send_message_noirq(MSM_RPM_CTX_ACTIVE_SET,
			RPM_MISC_CLK_TYPE, RPM_SCALING_ENABLE_ID, &kvp, 1);
	WARN(rc < 0, "RPM clock scaling (active set) did not enable!\n");
}

struct clk_ops clk_ops_rpm = {
	.prepare = rpm_clk_prepare,
	.unprepare = rpm_clk_unprepare,
	.set_rate = rpm_clk_set_rate,
	.get_rate = rpm_clk_get_rate,
	.is_enabled = rpm_clk_is_enabled,
	.round_rate = rpm_clk_round_rate,
	.is_local = rpm_clk_is_local,
	.handoff = rpm_clk_handoff,
};

struct clk_ops clk_ops_rpm_branch = {
	.prepare = rpm_clk_prepare,
	.unprepare = rpm_clk_unprepare,
	.set_rate = rpm_branch_clk_set_rate,
	.is_local = rpm_clk_is_local,
	.handoff = rpm_clk_handoff,
};