/*
 * Copyright (C) 2019 CERN (www.cern.ch)
 * Author: Miguel Jimenez Lopez <miguel.jimenez@sevensols.com>
 *
 * Released according to the GNU GPL, version 2 or any later version.
 *
 * This work is part of the White Rabbit project, a research effort led
 * by CERN, the European Institute for Nuclear Research.
 */

#ifdef __KERNEL__
#include <linux/platform_device.h>
#include <linux/miscdevice.h>
#include <linux/gpio.h>
#include <linux/irqreturn.h>
#include <linux/fmc.h>
//FIXME: Back hack to maintain the IOCTL command numbers
#include <linux/sockios.h>

#include "hw/wr-dio-regs.h"
#include "hw/ppsg-regs.h"

/* Forward declaration */
struct fmc_dio;

/* This is somehow generic, but I find no better place at this time */
#ifndef SET_HI32
#  if BITS_PER_LONG > 32
#    define SET_HI32(var, value)	((var) |= (long)(value) << 32)
#    define GET_HI32(var)		((var) >> 32)
#  else
#    define SET_HI32(var, value)	((var) |= 0)
#    define GET_HI32(var)		0
#  endif
#endif

/* For GPIO we have no wb-gen header */
struct fmc_dio_gpio_block {
	uint32_t	clear;
	uint32_t	set;
	uint32_t	dir;
	uint32_t	status;
};

/* And this is our bit mapping */
#define FMC_DIO_GPIO_VALUE(bit)	(1 << ((4 * (bit)) + 0))

/* FMC DIO name string pattern */
#define FMC_DIO_NAME_PATTERN "fmc-dio-%d:%d"
/* Size of the name field of the fmc_dio structure */
#define FMC_DIO_NAME_MAX 20

/* Board constants */
#define FMC_DIO_BOARD_SPEC 0
#define FMC_DIOv2_BOARD_SPEC 1

/**
 * @brief FMC DIO structure
 *
 * This contains information regarding FMC DIO.
 */
struct fmc_dio {
	char name[FMC_DIO_NAME_MAX]; /**< Name of the FMC DIO */
	struct miscdevice mdev; /**< Linux Miscdevice for the FMC DIO */
	struct platform_device *pdev; /**< Linux platform_device for the FMC DIO */
	struct fmc_device *fmc; /** FMC device for the FMC DIO */
	struct gpio_chip *gc; /**< Linux GPIO chip */

	void __iomem *dio; /**< DIO IP block pointer */
	void __iomem *gpio; /**< GPIO IP block pointer */
	void __iomem *ppsg; /**< PPSG IP block pointer */

	const char *irqdomain_name; /**< IRQ domain name */
	int irq; /**< IRQ number for DIO FMC */

	int board; /**< Board info */

	int version; //*< HDL version */

	void *priv; /**< Private data for FMC DIO */
};

// From fmc-dio-internal.c
extern irqreturn_t fmc_dio_int_interrupt(struct fmc_dio *dev);
extern int fmc_dio_int_ioctl(struct fmc_dio *dev, unsigned int ioctlcmd,
		unsigned long arg);
extern int fmc_dio_internal_create(struct fmc_dio *dev);
extern void fmc_dio_internal_destroy(struct fmc_dio *dev);

// From fmc-dio-mdev.c
extern int fmc_dio_mdev_create(struct fmc_dio *dio);
extern void fmc_dio_mdev_destroy(struct fmc_dio *dio);

// From fmc-dio-gpio.c
extern int fmc_dio_gpio_init(struct fmc_dio *dev);
extern void fmc_dio_gpio_exit(struct fmc_dio *dev);

#endif /* __KERNEL__ */

// FIXME: Move IOCTL command numbers?
#define PRIV_MEZZANINE_ID	(SIOCDEVPRIVATE + 14)
#define PRIV_MEZZANINE_CMD	(SIOCDEVPRIVATE + 15)

// FMC DIO Commands
enum wr_dio_cmd_name {
	WR_DIO_CMD_PULSE,
	WR_DIO_CMD_STAMP,
	WR_DIO_CMD_DAC,
	WR_DIO_CMD_INOUT,
	WR_DIO_CMD_IRQ,
	WR_DIO_CMD_UPDATE_WIDTH,
	WR_DIO_CMD_MASK_IRQ,
};

/*
 * This is how parameters are used (K == reply from kernel):
 *
 *  CMD_PULSE:
 *     cmd->flags: F_NOW, F_REL, F_LOOP
 *     cmd->channel: the channel or the mask
 *     cmd->t[]: either 2 or 3 values (start, duration, loop)
 *     cmd->value: count of loops (0 to turn off)
 *
 *  CMD_STAMP:
 *     cmd->flags: F_MASK, F_WAIT
 *     cmd->channel: the channel or the mask
 *     K: cmd->channel: the channel where we had stamps
 *     K: cmd->nstamp: number of valid stamps
 *     K: cmd->t[]: the stamps
 *
 *  CMD_DAC:
 *     cmd->flags: none
 *     cmd->channel: which one
 *     cmd->value: the value
 *
 *  CMD_INOUT:
 *     cmd->flags: F_MASK
 *     cmd->channel: the channel or the mask
 *     cmd->value: bits 0..4: WR-DIO, 8..12 value, 16..20 OEN, 24..28 term
 *
 */

#define WR_DIO_INOUT_DIO	(1 << 0)
#define WR_DIO_INOUT_VALUE	(1 << 8)
#define WR_DIO_INOUT_OUTPUT	(1 << 16)
#define WR_DIO_INOUT_TERM	(1 << 24)

#define WR_DIO_N_STAMP  16 /* At least 5 * 3 */

struct wr_timestamp_info {
   uint16_t leap_second;
   int leap_second_valid;
   int flag59;
   int flag61;
};

struct wr_dio_cmd {
	uint16_t command;	/* from user */
	uint16_t channel;	/* 0..4 or mask from user */
	uint32_t value;		/* for DAC or I/O */
	uint32_t flags;
	uint32_t nstamp;	/* from kernel, if IN_STAMP */
	struct timespec t[WR_DIO_N_STAMP];
	struct wr_timestamp_info wr_ts_info_buf[WR_DIO_N_STAMP];
	uint32_t wait_mode_flags;
	struct timespec wait_mode_timeout;
};

#define WR_DIO_F_NOW	0x01	/* Output is now, t[0] ignored */
#define WR_DIO_F_REL	0x02	/* t[0].tv_sec is relative */
#define WR_DIO_F_MASK	0x04	/* Channel is 0x00..0x1f */
#define WR_DIO_F_LOOP	0x08	/* Output should loop: t[2] is  looping*/
#define WR_DIO_F_WAIT	0x10	/* Wait for event */
#define WR_DIO_F_MASK_READ_IRQ		0x20
#define WR_DIO_F_MASK_ENABLE_IRQ	0x40
#define WR_DIO_F_MASK_DISABLE_IRQ	0x80
#define WR_DIO_F_WAIT_MODE_NORM	0x00
#define WR_DIO_F_WAIT_MODE_TIMEOUT	0x01