// SPDX-License-Identifier: GPL-2.0-or-later
/*
    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

*/

/*
    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;

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;

                error = pci_read_config_word(dev, alt_reg, &iobase);
                if (error != 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;
        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 = kzalloc_objs(struct nforce2_smbus, 2);
        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;
        }

        return 0;
}


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

        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);