arch/m68k/mac/misc.c - linux - Git at Google

 // 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/setup.h>
 #include <asm/macintosh.h>
 #include <asm/mac_via.h>
 #include <asm/mac_oss.h>

 #include <asm/machdep.h>

 #include "mac.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 into the RTC 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)
 {
 #ifdef CONFIG_ADB_CUDA
 	if (macintosh_config->adb_type == MAC_ADB_EGRET ||
 	    macintosh_config->adb_type == MAC_ADB_CUDA) {
 		cuda_restart();
 	} else
 #endif
 #ifdef CONFIG_ADB_PMU
 	if (macintosh_config->adb_type == MAC_ADB_PB2) {
 		pmu_restart();
 	} else
 #endif
 	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");
 	} else {
 		/* 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();
 	}

 	/* 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;
 	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;
 	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;
 }
	// 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/setup.h>
	#include <asm/macintosh.h>
	#include <asm/mac_via.h>
	#include <asm/mac_oss.h>

	#include <asm/machdep.h>

	#include "mac.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 into the RTC 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)
	{
	#ifdef CONFIG_ADB_CUDA
	if (macintosh_config->adb_type == MAC_ADB_EGRET \|\|
	macintosh_config->adb_type == MAC_ADB_CUDA) {
	cuda_restart();
	} else
	#endif
	#ifdef CONFIG_ADB_PMU
	if (macintosh_config->adb_type == MAC_ADB_PB2) {
	pmu_restart();
	} else
	#endif
	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");
	} else {
	/* 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();
	}

	/* 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;
	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;
	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;
	}