system76-coreboot/src/southbridge/amd/pi/hudson/smbus.c

/* SPDX-License-Identifier: GPL-2.0-only */

#ifndef _HUDSON_SMBUS_C_
#define _HUDSON_SMBUS_C_

#include <arch/io.h>
#include <stdint.h>
#include "smbus.h"

static int smbus_wait_until_ready(u32 smbus_io_base)
{
	u32 loops;

	loops = SMBUS_TIMEOUT;
	do {
		u8 val;
		val = inb(smbus_io_base + SMBHSTSTAT);
		val &= 0x1f;
		if (val == 0) {	/* ready now */
			return 0;
		}
		outb(val, smbus_io_base + SMBHSTSTAT);
	} while (--loops);

	return -2;		/* time out */
}

static int smbus_wait_until_done(u32 smbus_io_base)
{
	u32 loops;

	loops = SMBUS_TIMEOUT;
	do {
		u8 val;

		val = inb(smbus_io_base + SMBHSTSTAT);
		val &= 0x1f;	/* mask off reserved bits */
		if (val & 0x1c) {
			return -5;	/* error */
		}
		if (val == 0x02) {
			outb(val, smbus_io_base + SMBHSTSTAT);	/* clear status */
			return 0;
		}
	} while (--loops);

	return -3;		/* timeout */
}

int do_smbus_recv_byte(u32 smbus_io_base, u32 device)
{
	u8 byte;

	if (smbus_wait_until_ready(smbus_io_base) < 0) {
		return -2;	/* not ready */
	}

	/* set the device I'm talking to */
	outb(((device & 0x7f) << 1) | 1, smbus_io_base + SMBHSTADDR);

	byte = inb(smbus_io_base + SMBHSTCTRL);
	byte &= 0xe3;		/* Clear [4:2] */
	byte |= (1 << 2) | (1 << 6);	/* Byte data read/write command, start the command */
	outb(byte, smbus_io_base + SMBHSTCTRL);

	/* poll for transaction completion */
	if (smbus_wait_until_done(smbus_io_base) < 0) {
		return -3;	/* timeout or error */
	}

	/* read results of transaction */
	byte = inb(smbus_io_base + SMBHSTCMD);

	return byte;
}

int do_smbus_send_byte(u32 smbus_io_base, u32 device, u8 val)
{
	u8 byte;

	if (smbus_wait_until_ready(smbus_io_base) < 0) {
		return -2;	/* not ready */
	}

	/* set the command... */
	outb(val, smbus_io_base + SMBHSTCMD);

	/* set the device I'm talking to */
	outb(((device & 0x7f) << 1) | 0, smbus_io_base + SMBHSTADDR);

	byte = inb(smbus_io_base + SMBHSTCTRL);
	byte &= 0xe3;		/* Clear [4:2] */
	byte |= (1 << 2) | (1 << 6);	/* Byte data read/write command, start the command */
	outb(byte, smbus_io_base + SMBHSTCTRL);

	/* poll for transaction completion */
	if (smbus_wait_until_done(smbus_io_base) < 0) {
		return -3;	/* timeout or error */
	}

	return 0;
}

int do_smbus_read_byte(u32 smbus_io_base, u32 device, u32 address)
{
	u8 byte;

	if (smbus_wait_until_ready(smbus_io_base) < 0) {
		return -2;	/* not ready */
	}

	/* set the command/address... */
	outb(address & 0xff, smbus_io_base + SMBHSTCMD);

	/* set the device I'm talking to */
	outb(((device & 0x7f) << 1) | 1, smbus_io_base + SMBHSTADDR);

	byte = inb(smbus_io_base + SMBHSTCTRL);
	byte &= 0xe3;		/* Clear [4:2] */
	byte |= (1 << 3) | (1 << 6);	/* Byte data read/write command, start the command */
	outb(byte, smbus_io_base + SMBHSTCTRL);

	/* poll for transaction completion */
	if (smbus_wait_until_done(smbus_io_base) < 0) {
		return -3;	/* timeout or error */
	}

	/* read results of transaction */
	byte = inb(smbus_io_base + SMBHSTDAT0);

	return byte;
}

int do_smbus_write_byte(u32 smbus_io_base, u32 device, u32 address, u8 val)
{
	u8 byte;

	if (smbus_wait_until_ready(smbus_io_base) < 0) {
		return -2;	/* not ready */
	}

	/* set the command/address... */
	outb(address & 0xff, smbus_io_base + SMBHSTCMD);

	/* set the device I'm talking to */
	outb(((device & 0x7f) << 1) | 0, smbus_io_base + SMBHSTADDR);

	/* output value */
	outb(val, smbus_io_base + SMBHSTDAT0);

	byte = inb(smbus_io_base + SMBHSTCTRL);
	byte &= 0xe3;		/* Clear [4:2] */
	byte |= (1 << 3) | (1 << 6);	/* Byte data read/write command, start the command */
	outb(byte, smbus_io_base + SMBHSTCTRL);

	/* poll for transaction completion */
	if (smbus_wait_until_done(smbus_io_base) < 0) {
		return -3;	/* timeout or error */
	}

	return 0;
}

void alink_ab_indx(u32 reg_space, u32 reg_addr, u32 mask, u32 val)
{
	u32 tmp;

	outl((reg_space & 0x7) << 29 | reg_addr, AB_INDX);
	tmp = inl(AB_DATA);
	/* rpr 4.2
	 * For certain revisions of the chip, the ABCFG registers,
	 * with an address of 0x100NN (where 'N' is any hexadecimal
	 * number), require an extra programming step.*/
	outl(0, AB_INDX);

	tmp &= ~mask;
	tmp |= val;

	/* printk(BIOS_DEBUG, "about write %x, index=%x", tmp, (reg_space&0x3)<<29 | reg_addr); */
	outl((reg_space & 0x7) << 29 | reg_addr, AB_INDX);	/* probably we don't have to do it again. */
	outl(tmp, AB_DATA);
	outl(0, AB_INDX);
}

void alink_rc_indx(u32 reg_space, u32 reg_addr, u32 port, u32 mask, u32 val)
{
	u32 tmp;

	outl((reg_space & 0x7) << 29 | (port & 3) << 24 | reg_addr, AB_INDX);
	tmp = inl(AB_DATA);
	/* rpr 4.2
	 * For certain revisions of the chip, the ABCFG registers,
	 * with an address of 0x100NN (where 'N' is any hexadecimal
	 * number), require an extra programming step.*/
	outl(0, AB_INDX);

	tmp &= ~mask;
	tmp |= val;

	//printk(BIOS_DEBUG, "about write %x, index=%x", tmp, (reg_space&0x3)<<29 | (port&3) << 24 | reg_addr);
	outl((reg_space & 0x7) << 29 | (port & 3) << 24 | reg_addr, AB_INDX);	/* probably we don't have to do it again. */
	outl(tmp, AB_DATA);
	outl(0, AB_INDX);
}

/* space = 0: AX_INDXC, AX_DATAC
 * space = 1: AX_INDXP, AX_DATAP
 */
void alink_ax_indx(u32 space /*c or p? */, u32 axindc, u32 mask, u32 val)
{
	u32 tmp;

	/* read axindc to tmp */
	outl(space << 29 | space << 3 | 0x30, AB_INDX);
	outl(axindc, AB_DATA);
	outl(0, AB_INDX);
	outl(space << 29 | space << 3 | 0x34, AB_INDX);
	tmp = inl(AB_DATA);
	outl(0, AB_INDX);

	tmp &= ~mask;
	tmp |= val;

	/* write tmp */
	outl(space << 29 | space << 3 | 0x30, AB_INDX);
	outl(axindc, AB_DATA);
	outl(0, AB_INDX);
	outl(space << 29 | space << 3 | 0x34, AB_INDX);
	outl(tmp, AB_DATA);
	outl(0, AB_INDX);
}
#endif