// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2000, 2001 Broadcom Corporation
 *
 * Copyright (C) 2002 MontaVista Software Inc.
 * Author: jsun@mvista.com or jsun@junsun.net
 */
#include <linux/bcd.h>
#include <linux/types.h>
#include <linux/time.h>

#include <asm/time.h>
#include <asm/addrspace.h>
#include <asm/io.h>

#include <asm/sibyte/sb1250.h>
#include <asm/sibyte/sb1250_regs.h>
#include <asm/sibyte/sb1250_smbus.h>


/* Xicor 1241 definitions */

/*
 * Register bits
 */

#define X1241REG_SR_BAT 0x80            /* currently on battery power */
#define X1241REG_SR_RWEL 0x04           /* r/w latch is enabled, can write RTC */
#define X1241REG_SR_WEL 0x02            /* r/w latch is unlocked, can enable r/w now */
#define X1241REG_SR_RTCF 0x01           /* clock failed */
#define X1241REG_BL_BP2 0x80            /* block protect 2 */
#define X1241REG_BL_BP1 0x40            /* block protect 1 */
#define X1241REG_BL_BP0 0x20            /* block protect 0 */
#define X1241REG_BL_WD1 0x10
#define X1241REG_BL_WD0 0x08
#define X1241REG_HR_MIL 0x80            /* military time format */

/*
 * Register numbers
 */

#define X1241REG_BL     0x10            /* block protect bits */
#define X1241REG_INT    0x11            /*  */
#define X1241REG_SC     0x30            /* Seconds */
#define X1241REG_MN     0x31            /* Minutes */
#define X1241REG_HR     0x32            /* Hours */
#define X1241REG_DT     0x33            /* Day of month */
#define X1241REG_MO     0x34            /* Month */
#define X1241REG_YR     0x35            /* Year */
#define X1241REG_DW     0x36            /* Day of Week */
#define X1241REG_Y2K    0x37            /* Year 2K */
#define X1241REG_SR     0x3F            /* Status register */

#define X1241_CCR_ADDRESS       0x6F

#define SMB_CSR(reg)    IOADDR(A_SMB_REGISTER(1, reg))

static int xicor_read(uint8_t addr)
{
        while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
                ;

        __raw_writeq((addr >> 8) & 0x7, SMB_CSR(R_SMB_CMD));
        __raw_writeq(addr & 0xff, SMB_CSR(R_SMB_DATA));
        __raw_writeq(V_SMB_ADDR(X1241_CCR_ADDRESS) | V_SMB_TT_WR2BYTE,
                     SMB_CSR(R_SMB_START));

        while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
                ;

        __raw_writeq(V_SMB_ADDR(X1241_CCR_ADDRESS) | V_SMB_TT_RD1BYTE,
                     SMB_CSR(R_SMB_START));

        while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
                ;

        if (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_ERROR) {
                /* Clear error bit by writing a 1 */
                __raw_writeq(M_SMB_ERROR, SMB_CSR(R_SMB_STATUS));
                return -1;
        }

        return __raw_readq(SMB_CSR(R_SMB_DATA)) & 0xff;
}

static int xicor_write(uint8_t addr, int b)
{
        while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
                ;

        __raw_writeq(addr, SMB_CSR(R_SMB_CMD));
        __raw_writeq((addr & 0xff) | ((b & 0xff) << 8), SMB_CSR(R_SMB_DATA));
        __raw_writeq(V_SMB_ADDR(X1241_CCR_ADDRESS) | V_SMB_TT_WR3BYTE,
                     SMB_CSR(R_SMB_START));

        while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
                ;

        if (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_ERROR) {
                /* Clear error bit by writing a 1 */
                __raw_writeq(M_SMB_ERROR, SMB_CSR(R_SMB_STATUS));
                return -1;
        } else {
                return 0;
        }
}

int xicor_set_time(time64_t t)
{
        struct rtc_time tm;
        int tmp;
        unsigned long flags;

        rtc_time64_to_tm(t, &tm);
        tm.tm_year += 1900;

        spin_lock_irqsave(&rtc_lock, flags);
        /* unlock writes to the CCR */
        xicor_write(X1241REG_SR, X1241REG_SR_WEL);
        xicor_write(X1241REG_SR, X1241REG_SR_WEL | X1241REG_SR_RWEL);

        /* trivial ones */
        tm.tm_sec = bin2bcd(tm.tm_sec);
        xicor_write(X1241REG_SC, tm.tm_sec);

        tm.tm_min = bin2bcd(tm.tm_min);
        xicor_write(X1241REG_MN, tm.tm_min);

        tm.tm_mday = bin2bcd(tm.tm_mday);
        xicor_write(X1241REG_DT, tm.tm_mday);

        /* tm_mon starts from 0, *ick* */
        tm.tm_mon ++;
        tm.tm_mon = bin2bcd(tm.tm_mon);
        xicor_write(X1241REG_MO, tm.tm_mon);

        /* year is split */
        tmp = tm.tm_year / 100;
        tm.tm_year %= 100;
        xicor_write(X1241REG_YR, tm.tm_year);
        xicor_write(X1241REG_Y2K, tmp);

        /* hour is the most tricky one */
        tmp = xicor_read(X1241REG_HR);
        if (tmp & X1241REG_HR_MIL) {
                /* 24 hour format */
                tm.tm_hour = bin2bcd(tm.tm_hour);
                tmp = (tmp & ~0x3f) | (tm.tm_hour & 0x3f);
        } else {
                /* 12 hour format, with 0x2 for pm */
                tmp = tmp & ~0x3f;
                if (tm.tm_hour >= 12) {
                        tmp |= 0x20;
                        tm.tm_hour -= 12;
                }
                tm.tm_hour = bin2bcd(tm.tm_hour);
                tmp |= tm.tm_hour;
        }
        xicor_write(X1241REG_HR, tmp);

        xicor_write(X1241REG_SR, 0);
        spin_unlock_irqrestore(&rtc_lock, flags);

        return 0;
}

time64_t xicor_get_time(void)
{
        unsigned int year, mon, day, hour, min, sec, y2k;
        unsigned long flags;

        spin_lock_irqsave(&rtc_lock, flags);
        sec = xicor_read(X1241REG_SC);
        min = xicor_read(X1241REG_MN);
        hour = xicor_read(X1241REG_HR);

        if (hour & X1241REG_HR_MIL) {
                hour &= 0x3f;
        } else {
                if (hour & 0x20)
                        hour = (hour & 0xf) + 0x12;
        }

        day = xicor_read(X1241REG_DT);
        mon = xicor_read(X1241REG_MO);
        year = xicor_read(X1241REG_YR);
        y2k = xicor_read(X1241REG_Y2K);
        spin_unlock_irqrestore(&rtc_lock, flags);

        sec = bcd2bin(sec);
        min = bcd2bin(min);
        hour = bcd2bin(hour);
        day = bcd2bin(day);
        mon = bcd2bin(mon);
        year = bcd2bin(year);
        y2k = bcd2bin(y2k);

        year += (y2k * 100);

        return mktime64(year, mon, day, hour, min, sec);
}

int xicor_probe(void)
{
        return xicor_read(X1241REG_SC) != -1;
}