// SPDX-License-Identifier: GPL-2.0
/*
 * Miscellaneous Mac68K-specific stuff
 */

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/time.h>
#include <linux/rtc.h>
#include <linux/mm.h>

#include <linux/adb.h>
#include <linux/cuda.h>
#include <linux/pmu.h>

#include <linux/uaccess.h>
#include <asm/io.h>
#include <asm/segment.h>
#include <asm/setup.h>
#include <asm/macintosh.h>
#include <asm/mac_via.h>
#include <asm/mac_oss.h>

#include <asm/machdep.h>

/*
 * Offset between Unix time (1970-based) and Mac time (1904-based). Cuda and PMU
 * times wrap in 2040. If we need to handle later times, the read_time functions
 * need to be changed to interpret wrapped times as post-2040.
 */

#define RTC_OFFSET 2082844800

static void (*rom_reset)(void);

#if IS_ENABLED(CONFIG_NVRAM)
#ifdef CONFIG_ADB_CUDA
static unsigned char cuda_pram_read_byte(int offset)
{
        struct adb_request req;

        if (cuda_request(&req, NULL, 4, CUDA_PACKET, CUDA_GET_PRAM,
                         (offset >> 8) & 0xFF, offset & 0xFF) < 0)
                return 0;
        while (!req.complete)
                cuda_poll();
        return req.reply[3];
}

static void cuda_pram_write_byte(unsigned char data, int offset)
{
        struct adb_request req;

        if (cuda_request(&req, NULL, 5, CUDA_PACKET, CUDA_SET_PRAM,
                         (offset >> 8) & 0xFF, offset & 0xFF, data) < 0)
                return;
        while (!req.complete)
                cuda_poll();
}
#endif /* CONFIG_ADB_CUDA */

#ifdef CONFIG_ADB_PMU
static unsigned char pmu_pram_read_byte(int offset)
{
        struct adb_request req;

        if (pmu_request(&req, NULL, 3, PMU_READ_XPRAM,
                        offset & 0xFF, 1) < 0)
                return 0;
        pmu_wait_complete(&req);

        return req.reply[0];
}

static void pmu_pram_write_byte(unsigned char data, int offset)
{
        struct adb_request req;

        if (pmu_request(&req, NULL, 4, PMU_WRITE_XPRAM,
                        offset & 0xFF, 1, data) < 0)
                return;
        pmu_wait_complete(&req);
}
#endif /* CONFIG_ADB_PMU */
#endif /* CONFIG_NVRAM */

/*
 * VIA PRAM/RTC access routines
 *
 * Must be called with interrupts disabled and
 * the RTC should be enabled.
 */

static __u8 via_rtc_recv(void)
{
        int i, reg;
        __u8 data;

        reg = via1[vBufB] & ~VIA1B_vRTCClk;

        /* Set the RTC data line to be an input. */

        via1[vDirB] &= ~VIA1B_vRTCData;

        /* The bits of the byte come out in MSB order */

        data = 0;
        for (i = 0 ; i < 8 ; i++) {
                via1[vBufB] = reg;
                via1[vBufB] = reg | VIA1B_vRTCClk;
                data = (data << 1) | (via1[vBufB] & VIA1B_vRTCData);
        }

        /* Return RTC data line to output state */

        via1[vDirB] |= VIA1B_vRTCData;

        return data;
}

static void via_rtc_send(__u8 data)
{
        int i, reg, bit;

        reg = via1[vBufB] & ~(VIA1B_vRTCClk | VIA1B_vRTCData);

        /* The bits of the byte go in in MSB order */

        for (i = 0 ; i < 8 ; i++) {
                bit = data & 0x80? 1 : 0;
                data <<= 1;
                via1[vBufB] = reg | bit;
                via1[vBufB] = reg | bit | VIA1B_vRTCClk;
        }
}

/*
 * These values can be found in Inside Macintosh vol. III ch. 2
 * which has a description of the RTC chip in the original Mac.
 */

#define RTC_FLG_READ            BIT(7)
#define RTC_FLG_WRITE_PROTECT   BIT(7)
#define RTC_CMD_READ(r)         (RTC_FLG_READ | (r << 2))
#define RTC_CMD_WRITE(r)        (r << 2)
#define RTC_REG_SECONDS_0       0
#define RTC_REG_SECONDS_1       1
#define RTC_REG_SECONDS_2       2
#define RTC_REG_SECONDS_3       3
#define RTC_REG_WRITE_PROTECT   13

/*
 * Inside Mac has no information about two-byte RTC commands but
 * the MAME/MESS source code has the essentials.
 */

#define RTC_REG_XPRAM           14
#define RTC_CMD_XPRAM_READ      (RTC_CMD_READ(RTC_REG_XPRAM) << 8)
#define RTC_CMD_XPRAM_WRITE     (RTC_CMD_WRITE(RTC_REG_XPRAM) << 8)
#define RTC_CMD_XPRAM_ARG(a)    (((a & 0xE0) << 3) | ((a & 0x1F) << 2))

/*
 * Execute a VIA PRAM/RTC command. For read commands
 * data should point to a one-byte buffer for the
 * resulting data. For write commands it should point
 * to the data byte to for the command.
 *
 * This function disables all interrupts while running.
 */

static void via_rtc_command(int command, __u8 *data)
{
        unsigned long flags;
        int is_read;

        local_irq_save(flags);

        /* The least significant bits must be 0b01 according to Inside Mac */

        command = (command & ~3) | 1;

        /* Enable the RTC and make sure the strobe line is high */

        via1[vBufB] = (via1[vBufB] | VIA1B_vRTCClk) & ~VIA1B_vRTCEnb;

        if (command & 0xFF00) {         /* extended (two-byte) command */
                via_rtc_send((command & 0xFF00) >> 8);
                via_rtc_send(command & 0xFF);
                is_read = command & (RTC_FLG_READ << 8);
        } else {                        /* one-byte command */
                via_rtc_send(command);
                is_read = command & RTC_FLG_READ;
        }
        if (is_read) {
                *data = via_rtc_recv();
        } else {
                via_rtc_send(*data);
        }

        /* All done, disable the RTC */

        via1[vBufB] |= VIA1B_vRTCEnb;

        local_irq_restore(flags);
}

#if IS_ENABLED(CONFIG_NVRAM)
static unsigned char via_pram_read_byte(int offset)
{
        unsigned char temp;

        via_rtc_command(RTC_CMD_XPRAM_READ | RTC_CMD_XPRAM_ARG(offset), &temp);

        return temp;
}

static void via_pram_write_byte(unsigned char data, int offset)
{
        unsigned char temp;

        temp = 0x55;
        via_rtc_command(RTC_CMD_WRITE(RTC_REG_WRITE_PROTECT), &temp);

        temp = data;
        via_rtc_command(RTC_CMD_XPRAM_WRITE | RTC_CMD_XPRAM_ARG(offset), &temp);

        temp = 0x55 | RTC_FLG_WRITE_PROTECT;
        via_rtc_command(RTC_CMD_WRITE(RTC_REG_WRITE_PROTECT), &temp);
}
#endif /* CONFIG_NVRAM */

/*
 * Return the current time in seconds since January 1, 1904.
 *
 * This only works on machines with the VIA-based PRAM/RTC, which
 * is basically any machine with Mac II-style ADB.
 */

static time64_t via_read_time(void)
{
        union {
                __u8 cdata[4];
                __u32 idata;
        } result, last_result;
        int count = 1;

        via_rtc_command(RTC_CMD_READ(RTC_REG_SECONDS_0), &last_result.cdata[3]);
        via_rtc_command(RTC_CMD_READ(RTC_REG_SECONDS_1), &last_result.cdata[2]);
        via_rtc_command(RTC_CMD_READ(RTC_REG_SECONDS_2), &last_result.cdata[1]);
        via_rtc_command(RTC_CMD_READ(RTC_REG_SECONDS_3), &last_result.cdata[0]);

        /*
         * The NetBSD guys say to loop until you get the same reading
         * twice in a row.
         */

        while (1) {
                via_rtc_command(RTC_CMD_READ(RTC_REG_SECONDS_0),
                                &result.cdata[3]);
                via_rtc_command(RTC_CMD_READ(RTC_REG_SECONDS_1),
                                &result.cdata[2]);
                via_rtc_command(RTC_CMD_READ(RTC_REG_SECONDS_2),
                                &result.cdata[1]);
                via_rtc_command(RTC_CMD_READ(RTC_REG_SECONDS_3),
                                &result.cdata[0]);

                if (result.idata == last_result.idata)
                        return (time64_t)result.idata - RTC_OFFSET;

                if (++count > 10)
                        break;

                last_result.idata = result.idata;
        }

        pr_err("%s: failed to read a stable value; got 0x%08x then 0x%08x\n",
               __func__, last_result.idata, result.idata);

        return 0;
}

/*
 * Set the current time to a number of seconds since January 1, 1904.
 *
 * This only works on machines with the VIA-based PRAM/RTC, which
 * is basically any machine with Mac II-style ADB.
 */

static void via_set_rtc_time(struct rtc_time *tm)
{
        union {
                __u8 cdata[4];
                __u32 idata;
        } data;
        __u8 temp;
        time64_t time;

        time = mktime64(tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday,
                        tm->tm_hour, tm->tm_min, tm->tm_sec);

        /* Clear the write protect bit */

        temp = 0x55;
        via_rtc_command(RTC_CMD_WRITE(RTC_REG_WRITE_PROTECT), &temp);

        data.idata = lower_32_bits(time + RTC_OFFSET);
        via_rtc_command(RTC_CMD_WRITE(RTC_REG_SECONDS_0), &data.cdata[3]);
        via_rtc_command(RTC_CMD_WRITE(RTC_REG_SECONDS_1), &data.cdata[2]);
        via_rtc_command(RTC_CMD_WRITE(RTC_REG_SECONDS_2), &data.cdata[1]);
        via_rtc_command(RTC_CMD_WRITE(RTC_REG_SECONDS_3), &data.cdata[0]);

        /* Set the write protect bit */

        temp = 0x55 | RTC_FLG_WRITE_PROTECT;
        via_rtc_command(RTC_CMD_WRITE(RTC_REG_WRITE_PROTECT), &temp);
}

static void via_shutdown(void)
{
        if (rbv_present) {
                via2[rBufB] &= ~0x04;
        } else {
                /* Direction of vDirB is output */
                via2[vDirB] |= 0x04;
                /* Send a value of 0 on that line */
                via2[vBufB] &= ~0x04;
                mdelay(1000);
        }
}

static void oss_shutdown(void)
{
        oss->rom_ctrl = OSS_POWEROFF;
}

#ifdef CONFIG_ADB_CUDA
static void cuda_restart(void)
{
        struct adb_request req;

        if (cuda_request(&req, NULL, 2, CUDA_PACKET, CUDA_RESET_SYSTEM) < 0)
                return;
        while (!req.complete)
                cuda_poll();
}

static void cuda_shutdown(void)
{
        struct adb_request req;

        if (cuda_request(&req, NULL, 2, CUDA_PACKET, CUDA_POWERDOWN) < 0)
                return;

        /* Avoid infinite polling loop when PSU is not under Cuda control */
        switch (macintosh_config->ident) {
        case MAC_MODEL_C660:
        case MAC_MODEL_Q605:
        case MAC_MODEL_Q605_ACC:
        case MAC_MODEL_P475:
        case MAC_MODEL_P475F:
                return;
        }

        while (!req.complete)
                cuda_poll();
}
#endif /* CONFIG_ADB_CUDA */

/*
 *-------------------------------------------------------------------
 * Below this point are the generic routines; they'll dispatch to the
 * correct routine for the hardware on which we're running.
 *-------------------------------------------------------------------
 */

#if IS_ENABLED(CONFIG_NVRAM)
unsigned char mac_pram_read_byte(int addr)
{
        switch (macintosh_config->adb_type) {
        case MAC_ADB_IOP:
        case MAC_ADB_II:
        case MAC_ADB_PB1:
                return via_pram_read_byte(addr);
#ifdef CONFIG_ADB_CUDA
        case MAC_ADB_EGRET:
        case MAC_ADB_CUDA:
                return cuda_pram_read_byte(addr);
#endif
#ifdef CONFIG_ADB_PMU
        case MAC_ADB_PB2:
                return pmu_pram_read_byte(addr);
#endif
        default:
                return 0xFF;
        }
}

void mac_pram_write_byte(unsigned char val, int addr)
{
        switch (macintosh_config->adb_type) {
        case MAC_ADB_IOP:
        case MAC_ADB_II:
        case MAC_ADB_PB1:
                via_pram_write_byte(val, addr);
                break;
#ifdef CONFIG_ADB_CUDA
        case MAC_ADB_EGRET:
        case MAC_ADB_CUDA:
                cuda_pram_write_byte(val, addr);
                break;
#endif
#ifdef CONFIG_ADB_PMU
        case MAC_ADB_PB2:
                pmu_pram_write_byte(val, addr);
                break;
#endif
        default:
                break;
        }
}

ssize_t mac_pram_get_size(void)
{
        return 256;
}
#endif /* CONFIG_NVRAM */

void mac_poweroff(void)
{
        if (oss_present) {
                oss_shutdown();
        } else if (macintosh_config->adb_type == MAC_ADB_II) {
                via_shutdown();
#ifdef CONFIG_ADB_CUDA
        } else if (macintosh_config->adb_type == MAC_ADB_EGRET ||
                   macintosh_config->adb_type == MAC_ADB_CUDA) {
                cuda_shutdown();
#endif
#ifdef CONFIG_ADB_PMU
        } else if (macintosh_config->adb_type == MAC_ADB_PB2) {
                pmu_shutdown();
#endif
        }

        pr_crit("It is now safe to turn off your Macintosh.\n");
        local_irq_disable();
        while(1);
}

void mac_reset(void)
{
        if (macintosh_config->adb_type == MAC_ADB_II &&
            macintosh_config->ident != MAC_MODEL_SE30) {
                /* need ROMBASE in booter */
                /* indeed, plus need to MAP THE ROM !! */

                if (mac_bi_data.rombase == 0)
                        mac_bi_data.rombase = 0x40800000;

                /* works on some */
                rom_reset = (void *) (mac_bi_data.rombase + 0xa);

                local_irq_disable();
                rom_reset();
#ifdef CONFIG_ADB_CUDA
        } else if (macintosh_config->adb_type == MAC_ADB_EGRET ||
                   macintosh_config->adb_type == MAC_ADB_CUDA) {
                cuda_restart();
#endif
#ifdef CONFIG_ADB_PMU
        } else if (macintosh_config->adb_type == MAC_ADB_PB2) {
                pmu_restart();
#endif
        } else if (CPU_IS_030) {

                /* 030-specific reset routine.  The idea is general, but the
                 * specific registers to reset are '030-specific.  Until I
                 * have a non-030 machine, I can't test anything else.
                 *  -- C. Scott Ananian <cananian@alumni.princeton.edu>
                 */

                unsigned long rombase = 0x40000000;

                /* make a 1-to-1 mapping, using the transparent tran. reg. */
                unsigned long virt = (unsigned long) mac_reset;
                unsigned long phys = virt_to_phys(mac_reset);
                unsigned long addr = (phys&0xFF000000)|0x8777;
                unsigned long offset = phys-virt;

                local_irq_disable(); /* lets not screw this up, ok? */
                __asm__ __volatile__(".chip 68030\n\t"
                                     "pmove %0,%/tt0\n\t"
                                     ".chip 68k"
                                     : : "m" (addr));
                /* Now jump to physical address so we can disable MMU */
                __asm__ __volatile__(
                    ".chip 68030\n\t"
                    "lea %/pc@(1f),%/a0\n\t"
                    "addl %0,%/a0\n\t"/* fixup target address and stack ptr */
                    "addl %0,%/sp\n\t"
                    "pflusha\n\t"
                    "jmp %/a0@\n\t" /* jump into physical memory */
                    "0:.long 0\n\t" /* a constant zero. */
                    /* OK.  Now reset everything and jump to reset vector. */
                    "1:\n\t"
                    "lea %/pc@(0b),%/a0\n\t"
                    "pmove %/a0@, %/tc\n\t" /* disable mmu */
                    "pmove %/a0@, %/tt0\n\t" /* disable tt0 */
                    "pmove %/a0@, %/tt1\n\t" /* disable tt1 */
                    "movel #0, %/a0\n\t"
                    "movec %/a0, %/vbr\n\t" /* clear vector base register */
                    "movec %/a0, %/cacr\n\t" /* disable caches */
                    "movel #0x0808,%/a0\n\t"
                    "movec %/a0, %/cacr\n\t" /* flush i&d caches */
                    "movew #0x2700,%/sr\n\t" /* set up status register */
                    "movel %1@(0x0),%/a0\n\t"/* load interrupt stack pointer */
                    "movec %/a0, %/isp\n\t"
                    "movel %1@(0x4),%/a0\n\t" /* load reset vector */
                    "reset\n\t" /* reset external devices */
                    "jmp %/a0@\n\t" /* jump to the reset vector */
                    ".chip 68k"
                    : : "r" (offset), "a" (rombase) : "a0");
        }

        /* should never get here */
        pr_crit("Restart failed. Please restart manually.\n");
        local_irq_disable();
        while(1);
}

/*
 * This function translates seconds since 1970 into a proper date.
 *
 * Algorithm cribbed from glibc2.1, __offtime().
 *
 * This is roughly same as rtc_time64_to_tm(), which we should probably
 * use here, but it's only available when CONFIG_RTC_LIB is enabled.
 */
#define SECS_PER_MINUTE (60)
#define SECS_PER_HOUR  (SECS_PER_MINUTE * 60)
#define SECS_PER_DAY   (SECS_PER_HOUR * 24)

static void unmktime(time64_t time, long offset,
                     int *yearp, int *monp, int *dayp,
                     int *hourp, int *minp, int *secp)
{
        /* How many days come before each month (0-12).  */
        static const unsigned short int __mon_yday[2][13] =
        {
                /* Normal years.  */
                { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
                /* Leap years.  */
                { 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
        };
        int days, rem, y, wday, yday;
        const unsigned short int *ip;

        days = div_u64_rem(time, SECS_PER_DAY, &rem);
        rem += offset;
        while (rem < 0) {
                rem += SECS_PER_DAY;
                --days;
        }
        while (rem >= SECS_PER_DAY) {
                rem -= SECS_PER_DAY;
                ++days;
        }
        *hourp = rem / SECS_PER_HOUR;
        rem %= SECS_PER_HOUR;
        *minp = rem / SECS_PER_MINUTE;
        *secp = rem % SECS_PER_MINUTE;
        /* January 1, 1970 was a Thursday. */
        wday = (4 + days) % 7; /* Day in the week. Not currently used */
        if (wday < 0) wday += 7;
        y = 1970;

#define DIV(a, b) ((a) / (b) - ((a) % (b) < 0))
#define LEAPS_THRU_END_OF(y) (DIV (y, 4) - DIV (y, 100) + DIV (y, 400))
#define __isleap(year)  \
  ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))

        while (days < 0 || days >= (__isleap (y) ? 366 : 365))
        {
                /* Guess a corrected year, assuming 365 days per year.  */
                long int yg = y + days / 365 - (days % 365 < 0);

                /* Adjust DAYS and Y to match the guessed year.  */
                days -= (yg - y) * 365 +
                        LEAPS_THRU_END_OF(yg - 1) - LEAPS_THRU_END_OF(y - 1);
                y = yg;
        }
        *yearp = y - 1900;
        yday = days; /* day in the year.  Not currently used. */
        ip = __mon_yday[__isleap(y)];
        for (y = 11; days < (long int) ip[y]; --y)
                continue;
        days -= ip[y];
        *monp = y;
        *dayp = days + 1; /* day in the month */
        return;
}

/*
 * Read/write the hardware clock.
 */

int mac_hwclk(int op, struct rtc_time *t)
{
        time64_t now;

        if (!op) { /* read */
                switch (macintosh_config->adb_type) {
                case MAC_ADB_IOP:
                case MAC_ADB_II:
                case MAC_ADB_PB1:
                        now = via_read_time();
                        break;
#ifdef CONFIG_ADB_CUDA
                case MAC_ADB_EGRET:
                case MAC_ADB_CUDA:
                        now = cuda_get_time();
                        break;
#endif
#ifdef CONFIG_ADB_PMU
                case MAC_ADB_PB2:
                        now = pmu_get_time();
                        break;
#endif
                default:
                        now = 0;
                }

                t->tm_wday = 0;
                unmktime(now, 0,
                         &t->tm_year, &t->tm_mon, &t->tm_mday,
                         &t->tm_hour, &t->tm_min, &t->tm_sec);
                pr_debug("%s: read %ptR\n", __func__, t);
        } else { /* write */
                pr_debug("%s: tried to write %ptR\n", __func__, t);

                switch (macintosh_config->adb_type) {
                case MAC_ADB_IOP:
                case MAC_ADB_II:
                case MAC_ADB_PB1:
                        via_set_rtc_time(t);
                        break;
#ifdef CONFIG_ADB_CUDA
                case MAC_ADB_EGRET:
                case MAC_ADB_CUDA:
                        cuda_set_rtc_time(t);
                        break;
#endif
#ifdef CONFIG_ADB_PMU
                case MAC_ADB_PB2:
                        pmu_set_rtc_time(t);
                        break;
#endif
                default:
                        return -ENODEV;
                }
        }
        return 0;
}