sym_nvram.c

内核linux2.4.20,可跟rtlinux3.2打补丁 组成实时linux系统,编译内核

			 u_char *gpreg)
{
	S24C16_set_bit(np, write_bit, gpreg, SET_BIT);
	S24C16_set_bit(np, 0, gpreg, SET_CLK);
	if (read_bit)
		*read_bit = INB (nc_gpreg);
	S24C16_set_bit(np, 0, gpreg, CLR_CLK);
	S24C16_set_bit(np, 0, gpreg, CLR_BIT);
}

/*
 *  Output an ACK to the NVRAM after reading,
 *  change GPIO0 to output and when done back to an input
 */
static void S24C16_write_ack(sdev_p np, u_char write_bit, u_char *gpreg, 
			    u_char *gpcntl)
{
	OUTB (nc_gpcntl, *gpcntl & 0xfe);
	S24C16_do_bit(np, 0, write_bit, gpreg);
	OUTB (nc_gpcntl, *gpcntl);
}

/*
 *  Input an ACK from NVRAM after writing,
 *  change GPIO0 to input and when done back to an output
 */
static void S24C16_read_ack(sdev_p np, u_char *read_bit, u_char *gpreg, 
			   u_char *gpcntl)
{
	OUTB (nc_gpcntl, *gpcntl | 0x01);
	S24C16_do_bit(np, read_bit, 1, gpreg);
	OUTB (nc_gpcntl, *gpcntl);
}

/*
 *  WRITE a byte to the NVRAM and then get an ACK to see it was accepted OK,
 *  GPIO0 must already be set as an output
 */
static void S24C16_write_byte(sdev_p np, u_char *ack_data, u_char write_data, 
			     u_char *gpreg, u_char *gpcntl)
{
	int x;
	
	for (x = 0; x < 8; x++)
		S24C16_do_bit(np, 0, (write_data >> (7 - x)) & 0x01, gpreg);
		
	S24C16_read_ack(np, ack_data, gpreg, gpcntl);
}

/*
 *  READ a byte from the NVRAM and then send an ACK to say we have got it,
 *  GPIO0 must already be set as an input
 */
static void S24C16_read_byte(sdev_p np, u_char *read_data, u_char ack_data, 
			    u_char *gpreg, u_char *gpcntl)
{
	int x;
	u_char read_bit;

	*read_data = 0;
	for (x = 0; x < 8; x++) {
		S24C16_do_bit(np, &read_bit, 1, gpreg);
		*read_data |= ((read_bit & 0x01) << (7 - x));
	}

	S24C16_write_ack(np, ack_data, gpreg, gpcntl);
}

/*
 *  Read 'len' bytes starting at 'offset'.
 */
static int sym_read_S24C16_nvram (sdev_p np, int offset, u_char *data, int len)
{
	u_char	gpcntl, gpreg;
	u_char	old_gpcntl, old_gpreg;
	u_char	ack_data;
	int	retv = 1;
	int	x;

	/* save current state of GPCNTL and GPREG */
	old_gpreg	= INB (nc_gpreg);
	old_gpcntl	= INB (nc_gpcntl);
	gpcntl		= old_gpcntl & 0x1c;

	/* set up GPREG & GPCNTL to set GPIO0 and GPIO1 in to known state */
	OUTB (nc_gpreg,  old_gpreg);
	OUTB (nc_gpcntl, gpcntl);

	/* this is to set NVRAM into a known state with GPIO0/1 both low */
	gpreg = old_gpreg;
	S24C16_set_bit(np, 0, &gpreg, CLR_CLK);
	S24C16_set_bit(np, 0, &gpreg, CLR_BIT);
		
	/* now set NVRAM inactive with GPIO0/1 both high */
	S24C16_stop(np, &gpreg);
	
	/* activate NVRAM */
	S24C16_start(np, &gpreg);

	/* write device code and random address MSB */
	S24C16_write_byte(np, &ack_data,
		0xa0 | ((offset >> 7) & 0x0e), &gpreg, &gpcntl);
	if (ack_data & 0x01)
		goto out;

	/* write random address LSB */
	S24C16_write_byte(np, &ack_data,
		offset & 0xff, &gpreg, &gpcntl);
	if (ack_data & 0x01)
		goto out;

	/* regenerate START state to set up for reading */
	S24C16_start(np, &gpreg);
	
	/* rewrite device code and address MSB with read bit set (lsb = 0x01) */
	S24C16_write_byte(np, &ack_data,
		0xa1 | ((offset >> 7) & 0x0e), &gpreg, &gpcntl);
	if (ack_data & 0x01)
		goto out;

	/* now set up GPIO0 for inputting data */
	gpcntl |= 0x01;
	OUTB (nc_gpcntl, gpcntl);
		
	/* input all requested data - only part of total NVRAM */
	for (x = 0; x < len; x++) 
		S24C16_read_byte(np, &data[x], (x == (len-1)), &gpreg, &gpcntl);

	/* finally put NVRAM back in inactive mode */
	gpcntl &= 0xfe;
	OUTB (nc_gpcntl, gpcntl);
	S24C16_stop(np, &gpreg);
	retv = 0;
out:
	/* return GPIO0/1 to original states after having accessed NVRAM */
	OUTB (nc_gpcntl, old_gpcntl);
	OUTB (nc_gpreg,  old_gpreg);

	return retv;
}

#undef SET_BIT
#undef CLR_BIT
#undef SET_CLK
#undef CLR_CLK

/*
 *  Try reading Symbios NVRAM.
 *  Return 0 if OK.
 */
static int sym_read_Symbios_nvram (sdev_p np, Symbios_nvram *nvram)
{
	static u_char Symbios_trailer[6] = {0xfe, 0xfe, 0, 0, 0, 0};
	u_char *data = (u_char *) nvram;
	int len  = sizeof(*nvram);
	u_short	csum;
	int x;

	/* probe the 24c16 and read the SYMBIOS 24c16 area */
	if (sym_read_S24C16_nvram (np, SYMBIOS_NVRAM_ADDRESS, data, len))
		return 1;

	/* check valid NVRAM signature, verify byte count and checksum */
	if (nvram->type != 0 ||
	    bcmp(nvram->trailer, Symbios_trailer, 6) ||
	    nvram->byte_count != len - 12)
		return 1;

	/* verify checksum */
	for (x = 6, csum = 0; x < len - 6; x++)
		csum += data[x];
	if (csum != nvram->checksum)
		return 1;

	return 0;
}

/*
 *  93C46 EEPROM reading.
 *
 *  GPOI0 - data in
 *  GPIO1 - data out
 *  GPIO2 - clock
 *  GPIO4 - chip select
 *
 *  Used by Tekram.
 */

/*
 *  Pulse clock bit in GPIO0
 */
static void T93C46_Clk(sdev_p np, u_char *gpreg)
{
	OUTB (nc_gpreg, *gpreg | 0x04);
	UDELAY (2);
	OUTB (nc_gpreg, *gpreg);
}

/* 
 *  Read bit from NVRAM
 */
static void T93C46_Read_Bit(sdev_p np, u_char *read_bit, u_char *gpreg)
{
	UDELAY (2);
	T93C46_Clk(np, gpreg);
	*read_bit = INB (nc_gpreg);
}

/*
 *  Write bit to GPIO0
 */
static void T93C46_Write_Bit(sdev_p np, u_char write_bit, u_char *gpreg)
{
	if (write_bit & 0x01)
		*gpreg |= 0x02;
	else
		*gpreg &= 0xfd;
		
	*gpreg |= 0x10;
		
	OUTB (nc_gpreg, *gpreg);
	UDELAY (2);

	T93C46_Clk(np, gpreg);
}

/*
 *  Send STOP condition to NVRAM - puts NVRAM to sleep... ZZZzzz!!
 */
static void T93C46_Stop(sdev_p np, u_char *gpreg)
{
	*gpreg &= 0xef;
	OUTB (nc_gpreg, *gpreg);
	UDELAY (2);

	T93C46_Clk(np, gpreg);
}

/*
 *  Send read command and address to NVRAM
 */
static void T93C46_Send_Command(sdev_p np, u_short write_data, 
				u_char *read_bit, u_char *gpreg)
{
	int x;

	/* send 9 bits, start bit (1), command (2), address (6)  */
	for (x = 0; x < 9; x++)
		T93C46_Write_Bit(np, (u_char) (write_data >> (8 - x)), gpreg);

	*read_bit = INB (nc_gpreg);
}

/*
 *  READ 2 bytes from the NVRAM
 */
static void T93C46_Read_Word(sdev_p np, u_short *nvram_data, u_char *gpreg)
{
	int x;
	u_char read_bit;

	*nvram_data = 0;
	for (x = 0; x < 16; x++) {
		T93C46_Read_Bit(np, &read_bit, gpreg);

		if (read_bit & 0x01)
			*nvram_data |=  (0x01 << (15 - x));
		else
			*nvram_data &= ~(0x01 << (15 - x));
	}
}

/*
 *  Read Tekram NvRAM data.
 */
static int T93C46_Read_Data(sdev_p np, u_short *data,int len,u_char *gpreg)
{
	u_char	read_bit;
	int	x;

	for (x = 0; x < len; x++)  {

		/* output read command and address */
		T93C46_Send_Command(np, 0x180 | x, &read_bit, gpreg);
		if (read_bit & 0x01)
			return 1; /* Bad */
		T93C46_Read_Word(np, &data[x], gpreg);
		T93C46_Stop(np, gpreg);
	}

	return 0;
}

/*
 *  Try reading 93C46 Tekram NVRAM.
 */
static int sym_read_T93C46_nvram (sdev_p np, Tekram_nvram *nvram)
{
	u_char gpcntl, gpreg;
	u_char old_gpcntl, old_gpreg;
	int retv = 1;

	/* save current state of GPCNTL and GPREG */
	old_gpreg	= INB (nc_gpreg);
	old_gpcntl	= INB (nc_gpcntl);

	/* set up GPREG & GPCNTL to set GPIO0/1/2/4 in to known state, 0 in,
	   1/2/4 out */
	gpreg = old_gpreg & 0xe9;
	OUTB (nc_gpreg, gpreg);
	gpcntl = (old_gpcntl & 0xe9) | 0x09;
	OUTB (nc_gpcntl, gpcntl);

	/* input all of NVRAM, 64 words */
	retv = T93C46_Read_Data(np, (u_short *) nvram,
				sizeof(*nvram) / sizeof(short), &gpreg);
	
	/* return GPIO0/1/2/4 to original states after having accessed NVRAM */
	OUTB (nc_gpcntl, old_gpcntl);
	OUTB (nc_gpreg,  old_gpreg);

	return retv;
}

/*
 *  Try reading Tekram NVRAM.
 *  Return 0 if OK.
 */
static int sym_read_Tekram_nvram (sdev_p np, Tekram_nvram *nvram)
{
	u_char *data = (u_char *) nvram;
	int len = sizeof(*nvram);
	u_short	csum;
	int x;

	switch (np->device_id) {
	case PCI_ID_SYM53C885:
	case PCI_ID_SYM53C895:
	case PCI_ID_SYM53C896:
		x = sym_read_S24C16_nvram(np, TEKRAM_24C16_NVRAM_ADDRESS,
					  data, len);
		break;
	case PCI_ID_SYM53C875:
		x = sym_read_S24C16_nvram(np, TEKRAM_24C16_NVRAM_ADDRESS,
					  data, len);
		if (!x)
			break;
	default:
		x = sym_read_T93C46_nvram(np, nvram);
		break;
	}
	if (x)
		return 1;

	/* verify checksum */
	for (x = 0, csum = 0; x < len - 1; x += 2)
		csum += data[x] + (data[x+1] << 8);
	if (csum != 0x1234)
		return 1;

	return 0;
}

#endif	/* SYM_CONF_NVRAM_SUPPORT */