/*
    SMBus driver for nVidia nForce2 MCP

    Added nForce3 Pro 150  Thomas Leibold <thomas@plx.com>,
	Ported to 2.5 Patrick Dreker <patrick@dreker.de>,
    Copyright (c) 2003  Hans-Frieder Vogt <hfvogt@arcor.de>,
    Based on
    SMBus 2.0 driver for AMD-8111 IO-Hub
    Copyright (c) 2002 Vojtech Pavlik

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
*/

/*
    SUPPORTED DEVICES		PCI ID
    nForce2 MCP			0064
    nForce2 Ultra 400 MCP	0084
    nForce3 Pro150 MCP		00D4
    nForce3 250Gb MCP		00E4
    nForce4 MCP			0052
    nForce4 MCP-04		0034
    nForce MCP51		0264
    nForce MCP55		0368
    nForce MCP61		03EB
    nForce MCP65		0446
    nForce MCP67		0542
    nForce MCP73		07D8
    nForce MCP78S		0752
    nForce MCP79		0AA2

    This driver supports the 2 SMBuses that are included in the MCP of the
    nForce2/3/4/5xx chipsets.
*/

/* Note: we assume there can only be one nForce2, with two SMBus interfaces */

#include <linux/module.h>
#include <linux/pci.h>
#include <linux/kernel.h>
#include <linux/stddef.h>
#include <linux/ioport.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/dmi.h>
#include <linux/acpi.h>
#include <linux/slab.h>
#include <linux/io.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Hans-Frieder Vogt <hfvogt@gmx.net>");
MODULE_DESCRIPTION("nForce2/3/4/5xx SMBus driver");


struct nforce2_smbus {
	struct i2c_adapter adapter;
	int base;
	int size;
	int blockops;
	int can_abort;
};


/*
 * nVidia nForce2 SMBus control register definitions
 * (Newer incarnations use standard BARs 4 and 5 instead)
 */
#define NFORCE_PCI_SMB1	0x50
#define NFORCE_PCI_SMB2	0x54


/*
 * ACPI 2.0 chapter 13 SMBus 2.0 EC register model
 */
#define NVIDIA_SMB_PRTCL	(smbus->base + 0x00)	/* protocol, PEC */
#define NVIDIA_SMB_STS		(smbus->base + 0x01)	/* status */
#define NVIDIA_SMB_ADDR		(smbus->base + 0x02)	/* address */
#define NVIDIA_SMB_CMD		(smbus->base + 0x03)	/* command */
#define NVIDIA_SMB_DATA		(smbus->base + 0x04)	/* 32 data registers */
#define NVIDIA_SMB_BCNT		(smbus->base + 0x24)	/* number of data
							   bytes */
#define NVIDIA_SMB_STATUS_ABRT	(smbus->base + 0x3c)	/* register used to
							   check the status of
							   the abort command */
#define NVIDIA_SMB_CTRL		(smbus->base + 0x3e)	/* control register */

#define NVIDIA_SMB_STATUS_ABRT_STS	0x01		/* Bit to notify that
							   abort succeeded */
#define NVIDIA_SMB_CTRL_ABORT	0x20
#define NVIDIA_SMB_STS_DONE	0x80
#define NVIDIA_SMB_STS_ALRM	0x40
#define NVIDIA_SMB_STS_RES	0x20
#define NVIDIA_SMB_STS_STATUS	0x1f

#define NVIDIA_SMB_PRTCL_WRITE			0x00
#define NVIDIA_SMB_PRTCL_READ			0x01
#define NVIDIA_SMB_PRTCL_QUICK			0x02
#define NVIDIA_SMB_PRTCL_BYTE			0x04
#define NVIDIA_SMB_PRTCL_BYTE_DATA		0x06
#define NVIDIA_SMB_PRTCL_WORD_DATA		0x08
#define NVIDIA_SMB_PRTCL_BLOCK_DATA		0x0a
#define NVIDIA_SMB_PRTCL_PEC			0x80

/* Misc definitions */
#define MAX_TIMEOUT	100

/* We disable the second SMBus channel on these boards */
static const struct dmi_system_id nforce2_dmi_blacklist2[] = {
	{
		.ident = "DFI Lanparty NF4 Expert",
		.matches = {
			DMI_MATCH(DMI_BOARD_VENDOR, "DFI Corp,LTD"),
			DMI_MATCH(DMI_BOARD_NAME, "LP UT NF4 Expert"),
		},
	},
	{ }
};

static struct pci_driver nforce2_driver;

/* For multiplexing support, we need a global reference to the 1st
   SMBus channel */
#if IS_ENABLED(CONFIG_I2C_NFORCE2_S4985)
struct i2c_adapter *nforce2_smbus;
EXPORT_SYMBOL_GPL(nforce2_smbus);

static void nforce2_set_reference(struct i2c_adapter *adap)
{
	nforce2_smbus = adap;
}
#else
static inline void nforce2_set_reference(struct i2c_adapter *adap) { }
#endif

static void nforce2_abort(struct i2c_adapter *adap)
{
	struct nforce2_smbus *smbus = adap->algo_data;
	int timeout = 0;
	unsigned char temp;

	dev_dbg(&adap->dev, "Aborting current transaction\n");

	outb_p(NVIDIA_SMB_CTRL_ABORT, NVIDIA_SMB_CTRL);
	do {
		msleep(1);
		temp = inb_p(NVIDIA_SMB_STATUS_ABRT);
	} while (!(temp & NVIDIA_SMB_STATUS_ABRT_STS) &&
			(timeout++ < MAX_TIMEOUT));
	if (!(temp & NVIDIA_SMB_STATUS_ABRT_STS))
		dev_err(&adap->dev, "Can't reset the smbus\n");
	outb_p(NVIDIA_SMB_STATUS_ABRT_STS, NVIDIA_SMB_STATUS_ABRT);
}

static int nforce2_check_status(struct i2c_adapter *adap)
{
	struct nforce2_smbus *smbus = adap->algo_data;
	int timeout = 0;
	unsigned char temp;

	do {
		msleep(1);
		temp = inb_p(NVIDIA_SMB_STS);
	} while ((!temp) && (timeout++ < MAX_TIMEOUT));

	if (timeout > MAX_TIMEOUT) {
		dev_dbg(&adap->dev, "SMBus Timeout!\n");
		if (smbus->can_abort)
			nforce2_abort(adap);
		return -ETIMEDOUT;
	}
	if (!(temp & NVIDIA_SMB_STS_DONE) || (temp & NVIDIA_SMB_STS_STATUS)) {
		dev_dbg(&adap->dev, "Transaction failed (0x%02x)!\n", temp);
		return -EIO;
	}
	return 0;
}

/* Return negative errno on error */
static s32 nforce2_access(struct i2c_adapter *adap, u16 addr,
		unsigned short flags, char read_write,
		u8 command, int size, union i2c_smbus_data *data)
{
	struct nforce2_smbus *smbus = adap->algo_data;
	unsigned char protocol, pec;
	u8 len;
	int i, status;

	protocol = (read_write == I2C_SMBUS_READ) ? NVIDIA_SMB_PRTCL_READ :
		NVIDIA_SMB_PRTCL_WRITE;
	pec = (flags & I2C_CLIENT_PEC) ? NVIDIA_SMB_PRTCL_PEC : 0;

	switch (size) {
	case I2C_SMBUS_QUICK:
		protocol |= NVIDIA_SMB_PRTCL_QUICK;
		read_write = I2C_SMBUS_WRITE;
		break;

	case I2C_SMBUS_BYTE:
		if (read_write == I2C_SMBUS_WRITE)
			outb_p(command, NVIDIA_SMB_CMD);
		protocol |= NVIDIA_SMB_PRTCL_BYTE;
		break;

	case I2C_SMBUS_BYTE_DATA:
		outb_p(command, NVIDIA_SMB_CMD);
		if (read_write == I2C_SMBUS_WRITE)
			outb_p(data->byte, NVIDIA_SMB_DATA);
		protocol |= NVIDIA_SMB_PRTCL_BYTE_DATA;
		break;

	case I2C_SMBUS_WORD_DATA:
		outb_p(command, NVIDIA_SMB_CMD);
		if (read_write == I2C_SMBUS_WRITE) {
			outb_p(data->word, NVIDIA_SMB_DATA);
			outb_p(data->word >> 8, NVIDIA_SMB_DATA + 1);
		}
		protocol |= NVIDIA_SMB_PRTCL_WORD_DATA | pec;
		break;

	case I2C_SMBUS_BLOCK_DATA:
		outb_p(command, NVIDIA_SMB_CMD);
		if (read_write == I2C_SMBUS_WRITE) {
			len = data->block[0];
			if ((len == 0) || (len > I2C_SMBUS_BLOCK_MAX)) {
				dev_err(&adap->dev,
					"Transaction failed (requested block size: %d)\n",
					len);
				return -EINVAL;
			}
			outb_p(len, NVIDIA_SMB_BCNT);
			for (i = 0; i < I2C_SMBUS_BLOCK_MAX; i++)
				outb_p(data->block[i + 1],
				       NVIDIA_SMB_DATA + i);
		}
		protocol |= NVIDIA_SMB_PRTCL_BLOCK_DATA | pec;
		break;

	default:
		dev_err(&adap->dev, "Unsupported transaction %d\n", size);
		return -EOPNOTSUPP;
	}

	outb_p((addr & 0x7f) << 1, NVIDIA_SMB_ADDR);
	outb_p(protocol, NVIDIA_SMB_PRTCL);

	status = nforce2_check_status(adap);
	if (status)
		return status;

	if (read_write == I2C_SMBUS_WRITE)
		return 0;

	switch (size) {
	case I2C_SMBUS_BYTE:
	case I2C_SMBUS_BYTE_DATA:
		data->byte = inb_p(NVIDIA_SMB_DATA);
		break;

	case I2C_SMBUS_WORD_DATA:
		data->word = inb_p(NVIDIA_SMB_DATA) |
			     (inb_p(NVIDIA_SMB_DATA + 1) << 8);
		break;

	case I2C_SMBUS_BLOCK_DATA:
		len = inb_p(NVIDIA_SMB_BCNT);
		if ((len <= 0) || (len > I2C_SMBUS_BLOCK_MAX)) {
			dev_err(&adap->dev,
				"Transaction failed (received block size: 0x%02x)\n",
				len);
			return -EPROTO;
		}
		for (i = 0; i < len; i++)
			data->block[i + 1] = inb_p(NVIDIA_SMB_DATA + i);
		data->block[0] = len;
		break;
	}

	return 0;
}


static u32 nforce2_func(struct i2c_adapter *adapter)
{
	/* other functionality might be possible, but is not tested */
	return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
	       I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
	       I2C_FUNC_SMBUS_PEC |
	       (((struct nforce2_smbus *)adapter->algo_data)->blockops ?
		I2C_FUNC_SMBUS_BLOCK_DATA : 0);
}

static const struct i2c_algorithm smbus_algorithm = {
	.smbus_xfer	= nforce2_access,
	.functionality	= nforce2_func,
};


static const struct pci_device_id nforce2_ids[] = {
	{ PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE2_SMBUS) },
	{ PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE2S_SMBUS) },
	{ PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE3_SMBUS) },
	{ PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE3S_SMBUS) },
	{ PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE4_SMBUS) },
	{ PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP04_SMBUS) },
	{ PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP51_SMBUS) },
	{ PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP55_SMBUS) },
	{ PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP61_SMBUS) },
	{ PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP65_SMBUS) },
	{ PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP67_SMBUS) },
	{ PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP73_SMBUS) },
	{ PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP78S_SMBUS) },
	{ PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP79_SMBUS) },
	{ 0 }
};

MODULE_DEVICE_TABLE(pci, nforce2_ids);


static int nforce2_probe_smb(struct pci_dev *dev, int bar, int alt_reg,
			     struct nforce2_smbus *smbus, const char *name)
{
	int error;

	smbus->base = pci_resource_start(dev, bar);
	if (smbus->base) {
		smbus->size = pci_resource_len(dev, bar);
	} else {
		/* Older incarnations of the device used non-standard BARs */
		u16 iobase;

		if (pci_read_config_word(dev, alt_reg, &iobase)
		    != PCIBIOS_SUCCESSFUL) {
			dev_err(&dev->dev, "Error reading PCI config for %s\n",
				name);
			return -EIO;
		}

		smbus->base = iobase & PCI_BASE_ADDRESS_IO_MASK;
		smbus->size = 64;
	}

	error = acpi_check_region(smbus->base, smbus->size,
				  nforce2_driver.name);
	if (error)
		return error;

	if (!request_region(smbus->base, smbus->size, nforce2_driver.name)) {
		dev_err(&smbus->adapter.dev, "Error requesting region %02x .. %02X for %s\n",
			smbus->base, smbus->base+smbus->size-1, name);
		return -EBUSY;
	}
	smbus->adapter.owner = THIS_MODULE;
	smbus->adapter.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
	smbus->adapter.algo = &smbus_algorithm;
	smbus->adapter.algo_data = smbus;
	smbus->adapter.dev.parent = &dev->dev;
	snprintf(smbus->adapter.name, sizeof(smbus->adapter.name),
		"SMBus nForce2 adapter at %04x", smbus->base);

	error = i2c_add_adapter(&smbus->adapter);
	if (error) {
		release_region(smbus->base, smbus->size);
		return error;
	}
	dev_info(&smbus->adapter.dev, "nForce2 SMBus adapter at %#x\n",
		smbus->base);
	return 0;
}


static int nforce2_probe(struct pci_dev *dev, const struct pci_device_id *id)
{
	struct nforce2_smbus *smbuses;
	int res1, res2;

	/* we support 2 SMBus adapters */
	smbuses = kcalloc(2, sizeof(struct nforce2_smbus), GFP_KERNEL);
	if (!smbuses)
		return -ENOMEM;
	pci_set_drvdata(dev, smbuses);

	switch (dev->device) {
	case PCI_DEVICE_ID_NVIDIA_NFORCE2_SMBUS:
	case PCI_DEVICE_ID_NVIDIA_NFORCE_MCP51_SMBUS:
	case PCI_DEVICE_ID_NVIDIA_NFORCE_MCP55_SMBUS:
		smbuses[0].blockops = 1;
		smbuses[1].blockops = 1;
		smbuses[0].can_abort = 1;
		smbuses[1].can_abort = 1;
	}

	/* SMBus adapter 1 */
	res1 = nforce2_probe_smb(dev, 4, NFORCE_PCI_SMB1, &smbuses[0], "SMB1");
	if (res1 < 0)
		smbuses[0].base = 0;	/* to have a check value */

	/* SMBus adapter 2 */
	if (dmi_check_system(nforce2_dmi_blacklist2)) {
		dev_err(&dev->dev, "Disabling SMB2 for safety reasons.\n");
		res2 = -EPERM;
		smbuses[1].base = 0;
	} else {
		res2 = nforce2_probe_smb(dev, 5, NFORCE_PCI_SMB2, &smbuses[1],
					 "SMB2");
		if (res2 < 0)
			smbuses[1].base = 0;	/* to have a check value */
	}

	if ((res1 < 0) && (res2 < 0)) {
		/* we did not find even one of the SMBuses, so we give up */
		kfree(smbuses);
		return -ENODEV;
	}

	nforce2_set_reference(&smbuses[0].adapter);
	return 0;
}


static void nforce2_remove(struct pci_dev *dev)
{
	struct nforce2_smbus *smbuses = pci_get_drvdata(dev);

	nforce2_set_reference(NULL);
	if (smbuses[0].base) {
		i2c_del_adapter(&smbuses[0].adapter);
		release_region(smbuses[0].base, smbuses[0].size);
	}
	if (smbuses[1].base) {
		i2c_del_adapter(&smbuses[1].adapter);
		release_region(smbuses[1].base, smbuses[1].size);
	}
	kfree(smbuses);
}

static struct pci_driver nforce2_driver = {
	.name		= "nForce2_smbus",
	.id_table	= nforce2_ids,
	.probe		= nforce2_probe,
	.remove		= nforce2_remove,
};

module_pci_driver(nforce2_driver);