/*
 * Copyright (C) STMicroelectronics 2009
 * Copyright (C) ST-Ericsson SA 2010
 *
 * License Terms: GNU General Public License v2
 * Author: Kumar Sanghvi <kumar.sanghvi@stericsson.com>
 * Author: Sundar Iyer <sundar.iyer@stericsson.com>
 * Author: Mattias Nilsson <mattias.i.nilsson@stericsson.com>
 *
 * U8500 PRCM Unit interface driver
 *
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/mutex.h>
#include <linux/completion.h>
#include <linux/jiffies.h>
#include <linux/bitops.h>
#include <linux/interrupt.h>
#include <linux/mfd/db8500-prcmu.h>

#include <mach/hardware.h>

#include "db8500-prcmu-regs.h"

/* Global var to runtime determine TCDM base for v2 or v1 */
static __iomem void *tcdm_base;

#define _MBOX_HEADER		(tcdm_base + 0xFE8)
#define MBOX_HEADER_REQ_MB0	(_MBOX_HEADER + 0x0)

#define REQ_MB1 (tcdm_base + 0xFD0)
#define REQ_MB5 (tcdm_base + 0xE44)

#define REQ_MB1_ARMOPP		(REQ_MB1 + 0x0)
#define REQ_MB1_APEOPP		(REQ_MB1 + 0x1)
#define REQ_MB1_BOOSTOPP	(REQ_MB1 + 0x2)

#define ACK_MB1 (tcdm_base + 0xE04)
#define ACK_MB5 (tcdm_base + 0xDF4)

#define ACK_MB1_CURR_ARMOPP		(ACK_MB1 + 0x0)
#define ACK_MB1_CURR_APEOPP		(ACK_MB1 + 0x1)

#define REQ_MB5_I2C_SLAVE_OP (REQ_MB5)
#define REQ_MB5_I2C_HW_BITS (REQ_MB5 + 1)
#define REQ_MB5_I2C_REG (REQ_MB5 + 2)
#define REQ_MB5_I2C_VAL (REQ_MB5 + 3)

#define ACK_MB5_I2C_STATUS (ACK_MB5 + 1)
#define ACK_MB5_I2C_VAL (ACK_MB5 + 3)

#define PRCM_AVS_VARM_MAX_OPP		(tcdm_base + 0x2E4)
#define PRCM_AVS_ISMODEENABLE		7
#define PRCM_AVS_ISMODEENABLE_MASK	(1 << PRCM_AVS_ISMODEENABLE)

#define I2C_WRITE(slave) \
	(((slave) << 1) | (cpu_is_u8500v2() ? BIT(6) : 0))
#define I2C_READ(slave) \
	(((slave) << 1) | (cpu_is_u8500v2() ? BIT(6) : 0) | BIT(0))
#define I2C_STOP_EN BIT(3)

enum mb1_h {
	MB1H_ARM_OPP = 1,
	MB1H_APE_OPP,
	MB1H_ARM_APE_OPP,
};

static struct {
	struct mutex lock;
	struct completion work;
	struct {
		u8 arm_opp;
		u8 ape_opp;
		u8 arm_status;
		u8 ape_status;
	} ack;
} mb1_transfer;

enum ack_mb5_status {
	I2C_WR_OK = 0x01,
	I2C_RD_OK = 0x02,
};

#define MBOX_BIT BIT
#define NUM_MBOX 8

static struct {
	struct mutex lock;
	struct completion work;
	bool failed;
	struct {
		u8 status;
		u8 value;
	} ack;
} mb5_transfer;

/**
 * prcmu_abb_read() - Read register value(s) from the ABB.
 * @slave:	The I2C slave address.
 * @reg:	The (start) register address.
 * @value:	The read out value(s).
 * @size:	The number of registers to read.
 *
 * Reads register value(s) from the ABB.
 * @size has to be 1 for the current firmware version.
 */
int prcmu_abb_read(u8 slave, u8 reg, u8 *value, u8 size)
{
	int r;

	if (size != 1)
		return -EINVAL;

	r = mutex_lock_interruptible(&mb5_transfer.lock);
	if (r)
		return r;

	while (readl(PRCM_MBOX_CPU_VAL) & MBOX_BIT(5))
		cpu_relax();

	writeb(I2C_READ(slave), REQ_MB5_I2C_SLAVE_OP);
	writeb(I2C_STOP_EN, REQ_MB5_I2C_HW_BITS);
	writeb(reg, REQ_MB5_I2C_REG);

	writel(MBOX_BIT(5), PRCM_MBOX_CPU_SET);
	if (!wait_for_completion_timeout(&mb5_transfer.work,
			msecs_to_jiffies(500))) {
		pr_err("prcmu: prcmu_abb_read timed out.\n");
		r = -EIO;
		goto unlock_and_return;
	}
	r = ((mb5_transfer.ack.status == I2C_RD_OK) ? 0 : -EIO);
	if (!r)
		*value = mb5_transfer.ack.value;

unlock_and_return:
	mutex_unlock(&mb5_transfer.lock);
	return r;
}
EXPORT_SYMBOL(prcmu_abb_read);

/**
 * prcmu_abb_write() - Write register value(s) to the ABB.
 * @slave:	The I2C slave address.
 * @reg:	The (start) register address.
 * @value:	The value(s) to write.
 * @size:	The number of registers to write.
 *
 * Reads register value(s) from the ABB.
 * @size has to be 1 for the current firmware version.
 */
int prcmu_abb_write(u8 slave, u8 reg, u8 *value, u8 size)
{
	int r;

	if (size != 1)
		return -EINVAL;

	r = mutex_lock_interruptible(&mb5_transfer.lock);
	if (r)
		return r;


	while (readl(PRCM_MBOX_CPU_VAL) & MBOX_BIT(5))
		cpu_relax();

	writeb(I2C_WRITE(slave), REQ_MB5_I2C_SLAVE_OP);
	writeb(I2C_STOP_EN, REQ_MB5_I2C_HW_BITS);
	writeb(reg, REQ_MB5_I2C_REG);
	writeb(*value, REQ_MB5_I2C_VAL);

	writel(MBOX_BIT(5), PRCM_MBOX_CPU_SET);
	if (!wait_for_completion_timeout(&mb5_transfer.work,
			msecs_to_jiffies(500))) {
		pr_err("prcmu: prcmu_abb_write timed out.\n");
		r = -EIO;
		goto unlock_and_return;
	}
	r = ((mb5_transfer.ack.status == I2C_WR_OK) ? 0 : -EIO);

unlock_and_return:
	mutex_unlock(&mb5_transfer.lock);
	return r;
}
EXPORT_SYMBOL(prcmu_abb_write);

static int set_ape_cpu_opps(u8 header, enum prcmu_ape_opp ape_opp,
			    enum prcmu_cpu_opp cpu_opp)
{
	bool do_ape;
	bool do_arm;
	int err = 0;

	do_ape = ((header == MB1H_APE_OPP) || (header == MB1H_ARM_APE_OPP));
	do_arm = ((header == MB1H_ARM_OPP) || (header == MB1H_ARM_APE_OPP));

	mutex_lock(&mb1_transfer.lock);

	while (readl(PRCM_MBOX_CPU_VAL) & MBOX_BIT(1))
		cpu_relax();

	writeb(0, MBOX_HEADER_REQ_MB0);
	writeb(cpu_opp, REQ_MB1_ARMOPP);
	writeb(ape_opp, REQ_MB1_APEOPP);
	writeb(0, REQ_MB1_BOOSTOPP);
	writel(MBOX_BIT(1), PRCM_MBOX_CPU_SET);
	wait_for_completion(&mb1_transfer.work);
	if ((do_ape) && (mb1_transfer.ack.ape_status != 0))
		err = -EIO;
	if ((do_arm) && (mb1_transfer.ack.arm_status != 0))
		err = -EIO;

	mutex_unlock(&mb1_transfer.lock);

	return err;
}

/**
 * prcmu_set_ape_opp() - Set the OPP of the APE.
 * @opp:	The OPP to set.
 *
 * This function sets the OPP of the APE.
 */
int prcmu_set_ape_opp(enum prcmu_ape_opp opp)
{
	return set_ape_cpu_opps(MB1H_APE_OPP, opp, APE_OPP_NO_CHANGE);
}
EXPORT_SYMBOL(prcmu_set_ape_opp);

/**
 * prcmu_set_cpu_opp() - Set the OPP of the CPU.
 * @opp:	The OPP to set.
 *
 * This function sets the OPP of the CPU.
 */
int prcmu_set_cpu_opp(enum prcmu_cpu_opp opp)
{
	return set_ape_cpu_opps(MB1H_ARM_OPP, CPU_OPP_NO_CHANGE, opp);
}
EXPORT_SYMBOL(prcmu_set_cpu_opp);

/**
 * prcmu_set_ape_cpu_opps() - Set the OPPs of the APE and the CPU.
 * @ape_opp:	The APE OPP to set.
 * @cpu_opp:	The CPU OPP to set.
 *
 * This function sets the OPPs of the APE and the CPU.
 */
int prcmu_set_ape_cpu_opps(enum prcmu_ape_opp ape_opp,
			   enum prcmu_cpu_opp cpu_opp)
{
	return set_ape_cpu_opps(MB1H_ARM_APE_OPP, ape_opp, cpu_opp);
}
EXPORT_SYMBOL(prcmu_set_ape_cpu_opps);

/**
 * prcmu_get_ape_opp() - Get the OPP of the APE.
 *
 * This function gets the OPP of the APE.
 */
enum prcmu_ape_opp prcmu_get_ape_opp(void)
{
	return readb(ACK_MB1_CURR_APEOPP);
}
EXPORT_SYMBOL(prcmu_get_ape_opp);

/**
 * prcmu_get_cpu_opp() - Get the OPP of the CPU.
 *
 * This function gets the OPP of the CPU. The OPP is specified in %%.
 * PRCMU_OPP_EXT is a special OPP value, not specified in %%.
 */
int prcmu_get_cpu_opp(void)
{
	return readb(ACK_MB1_CURR_ARMOPP);
}
EXPORT_SYMBOL(prcmu_get_cpu_opp);

bool prcmu_has_arm_maxopp(void)
{
	return (readb(PRCM_AVS_VARM_MAX_OPP) & PRCM_AVS_ISMODEENABLE_MASK)
		== PRCM_AVS_ISMODEENABLE_MASK;
}

static void read_mailbox_0(void)
{
	writel(MBOX_BIT(0), PRCM_ARM_IT1_CLEAR);
}

static void read_mailbox_1(void)
{
	mb1_transfer.ack.arm_opp = readb(ACK_MB1_CURR_ARMOPP);
	mb1_transfer.ack.ape_opp = readb(ACK_MB1_CURR_APEOPP);
	complete(&mb1_transfer.work);
	writel(MBOX_BIT(1), PRCM_ARM_IT1_CLEAR);
}

static void read_mailbox_2(void)
{
	writel(MBOX_BIT(2), PRCM_ARM_IT1_CLEAR);
}

static void read_mailbox_3(void)
{
	writel(MBOX_BIT(3), PRCM_ARM_IT1_CLEAR);
}

static void read_mailbox_4(void)
{
	writel(MBOX_BIT(4), PRCM_ARM_IT1_CLEAR);
}

static void read_mailbox_5(void)
{
	mb5_transfer.ack.status = readb(ACK_MB5_I2C_STATUS);
	mb5_transfer.ack.value = readb(ACK_MB5_I2C_VAL);
	complete(&mb5_transfer.work);
	writel(MBOX_BIT(5), PRCM_ARM_IT1_CLEAR);
}

static void read_mailbox_6(void)
{
	writel(MBOX_BIT(6), PRCM_ARM_IT1_CLEAR);
}

static void read_mailbox_7(void)
{
	writel(MBOX_BIT(7), PRCM_ARM_IT1_CLEAR);
}

static void (* const read_mailbox[NUM_MBOX])(void) = {
	read_mailbox_0,
	read_mailbox_1,
	read_mailbox_2,
	read_mailbox_3,
	read_mailbox_4,
	read_mailbox_5,
	read_mailbox_6,
	read_mailbox_7
};

static irqreturn_t prcmu_irq_handler(int irq, void *data)
{
	u32 bits;
	u8 n;

	bits = (readl(PRCM_ARM_IT1_VAL) & (MBOX_BIT(NUM_MBOX) - 1));
	if (unlikely(!bits))
		return IRQ_NONE;

	for (n = 0; bits; n++) {
		if (bits & MBOX_BIT(n)) {
			bits -= MBOX_BIT(n);
			read_mailbox[n]();
		}
	}
	return IRQ_HANDLED;
}

void __init prcmu_early_init(void)
{
	if (cpu_is_u8500v11() || cpu_is_u8500ed()) {
		tcdm_base = __io_address(U8500_PRCMU_TCDM_BASE_V1);
	} else if (cpu_is_u8500v2()) {
		tcdm_base = __io_address(U8500_PRCMU_TCDM_BASE);
	} else {
		pr_err("prcmu: Unsupported chip version\n");
		BUG();
	}
}

static int __init prcmu_init(void)
{
	if (cpu_is_u8500ed()) {
		pr_err("prcmu: Unsupported chip version\n");
		return 0;
	}

	mutex_init(&mb1_transfer.lock);
	init_completion(&mb1_transfer.work);
	mutex_init(&mb5_transfer.lock);
	init_completion(&mb5_transfer.work);

	/* Clean up the mailbox interrupts after pre-kernel code. */
	writel((MBOX_BIT(NUM_MBOX) - 1), PRCM_ARM_IT1_CLEAR);

	return request_irq(IRQ_DB8500_PRCMU1, prcmu_irq_handler, 0,
			   "prcmu", NULL);
}

arch_initcall(prcmu_init);