misc.c

讲述linux的初始化过程

/*
 * Miscellaneous Mac68K-specific stuff 
 */

#include <stdarg.h>
#include <linux/config.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/miscdevice.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/malloc.h>
#include <linux/time.h>
#include <linux/kd.h>
#include <linux/mm.h>

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

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

#define BOOTINFO_COMPAT_1_0
#include <asm/bootinfo.h>
#include <asm/machdep.h>

/* Offset between Unix time (1970-based) and Mac time (1904-based) */

#define RTC_OFFSET 2082844800

extern struct mac_booter_data mac_bi_data;
static void (*rom_reset)(void);

/*
 * Return the current time as the number of seconds since January 1, 1904.
 */

static long adb_read_time(void)
{
	volatile struct adb_request req;
	long time;

	adb_request((struct adb_request *) &req, NULL,
			ADBREQ_RAW|ADBREQ_SYNC,
			2, CUDA_PACKET, CUDA_GET_TIME);

	time = (req.reply[3] << 24) | (req.reply[4] << 16)
		| (req.reply[5] << 8) | req.reply[6];
	return time - RTC_OFFSET;
}

/*
 * Set the current system time
 */

static void adb_write_time(long data)
{
	volatile struct adb_request req;

	data += RTC_OFFSET;
	
	adb_request((struct adb_request *) &req, NULL,
			ADBREQ_RAW|ADBREQ_SYNC,
			6, CUDA_PACKET, CUDA_SET_TIME,
			(data >> 24) & 0xFF, (data >> 16) & 0xFF,
			(data >> 8) & 0xFF, data & 0xFF);
}

/*
 * Get a byte from the NVRAM
 */

static __u8 adb_read_pram(int offset)
{
	volatile struct adb_request req;

	adb_request((struct adb_request *) &req, NULL,
			ADBREQ_RAW|ADBREQ_SYNC,
			4, CUDA_PACKET, CUDA_GET_PRAM,
			(offset >> 8) & 0xFF, offset & 0xFF);
	return req.reply[3];
}

/*
 * Write a byte to the NVRAM
 */

static void adb_write_pram(int offset, __u8 data)
{
	volatile struct adb_request req;

	adb_request((struct adb_request *) &req, NULL,
			ADBREQ_RAW|ADBREQ_SYNC,
			5, CUDA_PACKET, CUDA_SET_PRAM,
			(offset >> 8) & 0xFF, offset & 0xFF,
			data);
}

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

static __u8 via_pram_readbyte(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_pram_writebyte(__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;
	}
}

/*
 * 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_pram_command(int command, __u8 *data)
{
	unsigned long cpu_flags;
	int	is_read;

	save_flags(cpu_flags);
	cli();

	/* 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_pram_writebyte((command & 0xFF00) >> 8);
		via_pram_writebyte(command & 0xFF);
		is_read = command & 0x8000;
	} else {			/* one-byte command */
		via_pram_writebyte(command);
		is_read = command & 0x80;
	}
	if (is_read) {
		*data = via_pram_readbyte();
	} else {
		via_pram_writebyte(*data);
	}

	/* All done, disable the RTC */

	via1[vBufB] |= VIA1B_vRTCEnb;

	restore_flags(cpu_flags);
}

static __u8 via_read_pram(int offset)
{
	return 0;
}

static void via_write_pram(int offset, __u8 data)
{
}

/*
 * 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 long via_read_time(void)
{
	union {
		__u8  cdata[4];
		long  idata;
	} result, last_result;
	int	ct;

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

	ct = 0;
	do {
		if (++ct > 10) {
			printk("via_read_time: couldn't get valid time, "
			       "last read = 0x%08X and 0x%08X\n", last_result.idata,
			       result.idata);
			break;
		}

		last_result.idata = result.idata;
		result.idata = 0;

		via_pram_command(0x81, &result.cdata[3]);
		via_pram_command(0x85, &result.cdata[2]);
		via_pram_command(0x89, &result.cdata[1]);
		via_pram_command(0x8D, &result.cdata[0]);
	} while (result.idata != last_result.idata);

	return result.idata - RTC_OFFSET;
}

/*
 * 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_write_time(long time)
{
	union {
		__u8  cdata[4];
		long  idata;
	} data;
	__u8	temp;

	/* Clear the write protect bit */

	temp = 0x55;
	via_pram_command(0x35, &temp);

	data.idata = time + RTC_OFFSET;
	via_pram_command(0x01, &data.cdata[3]);
	via_pram_command(0x05, &data.cdata[2]);
	via_pram_command(0x09, &data.cdata[1]);
	via_pram_command(0x0D, &data.cdata[0]);

	/* Set the write protect bit */

	temp = 0xD5;
	via_pram_command(0x35, &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);
	}
}

/*
 * FIXME: not sure how this is supposed to work exactly...
 */

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

#ifdef CONFIG_ADB_CUDA

static void cuda_restart(void)
{
	adb_request(NULL, NULL, ADBREQ_RAW|ADBREQ_SYNC,
			2, CUDA_PACKET, CUDA_RESET_SYSTEM);
}

static void cuda_shutdown(void)
{
	adb_request(NULL, NULL, ADBREQ_RAW|ADBREQ_SYNC,
			2, CUDA_PACKET, CUDA_POWERDOWN);
}

#endif /* CONFIG_ADB_CUDA */

#ifdef CONFIG_ADB_PMU

void pmu_restart(void)
{
	adb_request(NULL, NULL, ADBREQ_RAW|ADBREQ_SYNC,
			3, PMU_PACKET, PMU_SET_INTR_MASK,
			PMU_INT_ADB|PMU_INT_TICK);
	
	adb_request(NULL, NULL, ADBREQ_RAW|ADBREQ_SYNC,
			2, PMU_PACKET, PMU_RESET);
}