// SPDX-License-Identifier: GPL-2.0-only
/*
 *      i2c-ali1563.c - i2c driver for the ALi 1563 Southbridge
 *
 *      Copyright (C) 2004 Patrick Mochel
 *                    2005 Rudolf Marek <r.marek@assembler.cz>
 *
 *      The 1563 southbridge is deceptively similar to the 1533, with a
 *      few notable exceptions. One of those happens to be the fact they
 *      upgraded the i2c core to be 2.0 compliant, and happens to be almost
 *      identical to the i2c controller found in the Intel 801 south
 *      bridges.
 *
 *      This driver is based on a mix of the 15x3, 1535, and i801 drivers,
 *      with a little help from the ALi 1563 spec.
 */

#include <linux/module.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/pci.h>
#include <linux/acpi.h>

#define ALI1563_MAX_TIMEOUT     500
#define ALI1563_SMBBA           0x80
#define ALI1563_SMB_IOEN        1
#define ALI1563_SMB_HOSTEN      2
#define ALI1563_SMB_IOSIZE      16

#define SMB_HST_STS     (ali1563_smba + 0)
#define SMB_HST_CNTL1   (ali1563_smba + 1)
#define SMB_HST_CNTL2   (ali1563_smba + 2)
#define SMB_HST_CMD     (ali1563_smba + 3)
#define SMB_HST_ADD     (ali1563_smba + 4)
#define SMB_HST_DAT0    (ali1563_smba + 5)
#define SMB_HST_DAT1    (ali1563_smba + 6)
#define SMB_BLK_DAT     (ali1563_smba + 7)

#define HST_STS_BUSY    0x01
#define HST_STS_INTR    0x02
#define HST_STS_DEVERR  0x04
#define HST_STS_BUSERR  0x08
#define HST_STS_FAIL    0x10
#define HST_STS_DONE    0x80
#define HST_STS_BAD     0x1c


#define HST_CNTL1_TIMEOUT       0x80
#define HST_CNTL1_LAST          0x40

#define HST_CNTL2_KILL          0x04
#define HST_CNTL2_START         0x40
#define HST_CNTL2_QUICK         0x00
#define HST_CNTL2_BYTE          0x01
#define HST_CNTL2_BYTE_DATA     0x02
#define HST_CNTL2_WORD_DATA     0x03
#define HST_CNTL2_BLOCK         0x05


#define HST_CNTL2_SIZEMASK      0x38

static struct pci_driver ali1563_pci_driver;
static unsigned short ali1563_smba;

static int ali1563_transaction(struct i2c_adapter *a, int size)
{
        u32 data;
        int timeout;
        int status = -EIO;

        dev_dbg(&a->dev, "Transaction (pre): STS=%02x, CNTL1=%02x, "
                "CNTL2=%02x, CMD=%02x, ADD=%02x, DAT0=%02x, DAT1=%02x\n",
                inb_p(SMB_HST_STS), inb_p(SMB_HST_CNTL1), inb_p(SMB_HST_CNTL2),
                inb_p(SMB_HST_CMD), inb_p(SMB_HST_ADD), inb_p(SMB_HST_DAT0),
                inb_p(SMB_HST_DAT1));

        data = inb_p(SMB_HST_STS);
        if (data & HST_STS_BAD) {
                dev_err(&a->dev, "ali1563: Trying to reset busy device\n");
                outb_p(data | HST_STS_BAD, SMB_HST_STS);
                data = inb_p(SMB_HST_STS);
                if (data & HST_STS_BAD)
                        return -EBUSY;
        }
        outb_p(inb_p(SMB_HST_CNTL2) | HST_CNTL2_START, SMB_HST_CNTL2);

        timeout = ALI1563_MAX_TIMEOUT;
        do {
                msleep(1);
        } while (((data = inb_p(SMB_HST_STS)) & HST_STS_BUSY) && --timeout);

        dev_dbg(&a->dev, "Transaction (post): STS=%02x, CNTL1=%02x, "
                "CNTL2=%02x, CMD=%02x, ADD=%02x, DAT0=%02x, DAT1=%02x\n",
                inb_p(SMB_HST_STS), inb_p(SMB_HST_CNTL1), inb_p(SMB_HST_CNTL2),
                inb_p(SMB_HST_CMD), inb_p(SMB_HST_ADD), inb_p(SMB_HST_DAT0),
                inb_p(SMB_HST_DAT1));

        if (timeout && !(data & HST_STS_BAD))
                return 0;

        if (!timeout) {
                /* Issue 'kill' to host controller */
                outb_p(HST_CNTL2_KILL, SMB_HST_CNTL2);
                data = inb_p(SMB_HST_STS);
                status = -ETIMEDOUT;
        }

        /* device error - no response, ignore the autodetection case */
        if (data & HST_STS_DEVERR) {
                if (size != HST_CNTL2_QUICK)
                        dev_err(&a->dev, "Device error!\n");
                status = -ENXIO;
        }
        /* bus collision */
        if (data & HST_STS_BUSERR) {
                dev_err(&a->dev, "Bus collision!\n");
                /* Issue timeout, hoping it helps */
                outb_p(HST_CNTL1_TIMEOUT, SMB_HST_CNTL1);
        }

        if (data & HST_STS_FAIL) {
                dev_err(&a->dev, "Cleaning fail after KILL!\n");
                outb_p(0x0, SMB_HST_CNTL2);
        }

        return status;
}

static int ali1563_block_start(struct i2c_adapter *a)
{
        u32 data;
        int timeout;
        int status = -EIO;

        dev_dbg(&a->dev, "Block (pre): STS=%02x, CNTL1=%02x, "
                "CNTL2=%02x, CMD=%02x, ADD=%02x, DAT0=%02x, DAT1=%02x\n",
                inb_p(SMB_HST_STS), inb_p(SMB_HST_CNTL1), inb_p(SMB_HST_CNTL2),
                inb_p(SMB_HST_CMD), inb_p(SMB_HST_ADD), inb_p(SMB_HST_DAT0),
                inb_p(SMB_HST_DAT1));

        data = inb_p(SMB_HST_STS);
        if (data & HST_STS_BAD) {
                dev_warn(&a->dev, "ali1563: Trying to reset busy device\n");
                outb_p(data | HST_STS_BAD, SMB_HST_STS);
                data = inb_p(SMB_HST_STS);
                if (data & HST_STS_BAD)
                        return -EBUSY;
        }

        /* Clear byte-ready bit */
        outb_p(data | HST_STS_DONE, SMB_HST_STS);

        /* Start transaction and wait for byte-ready bit to be set */
        outb_p(inb_p(SMB_HST_CNTL2) | HST_CNTL2_START, SMB_HST_CNTL2);

        timeout = ALI1563_MAX_TIMEOUT;
        do {
                msleep(1);
        } while (!((data = inb_p(SMB_HST_STS)) & HST_STS_DONE) && --timeout);

        dev_dbg(&a->dev, "Block (post): STS=%02x, CNTL1=%02x, "
                "CNTL2=%02x, CMD=%02x, ADD=%02x, DAT0=%02x, DAT1=%02x\n",
                inb_p(SMB_HST_STS), inb_p(SMB_HST_CNTL1), inb_p(SMB_HST_CNTL2),
                inb_p(SMB_HST_CMD), inb_p(SMB_HST_ADD), inb_p(SMB_HST_DAT0),
                inb_p(SMB_HST_DAT1));

        if (timeout && !(data & HST_STS_BAD))
                return 0;

        if (timeout == 0)
                status = -ETIMEDOUT;

        if (data & HST_STS_DEVERR)
                status = -ENXIO;

        dev_err(&a->dev, "SMBus Error: %s%s%s%s%s\n",
                timeout ? "" : "Timeout ",
                data & HST_STS_FAIL ? "Transaction Failed " : "",
                data & HST_STS_BUSERR ? "No response or Bus Collision " : "",
                data & HST_STS_DEVERR ? "Device Error " : "",
                !(data & HST_STS_DONE) ? "Transaction Never Finished " : "");
        return status;
}

static int ali1563_block(struct i2c_adapter *a,
                         union i2c_smbus_data *data, u8 rw)
{
        int i, len;
        int error = 0;

        /* Do we need this? */
        outb_p(HST_CNTL1_LAST, SMB_HST_CNTL1);

        if (rw == I2C_SMBUS_WRITE) {
                len = data->block[0];
                if (len < 1)
                        len = 1;
                else if (len > 32)
                        len = 32;
                outb_p(len, SMB_HST_DAT0);
                outb_p(data->block[1], SMB_BLK_DAT);
        } else
                len = 32;

        outb_p(inb_p(SMB_HST_CNTL2) | HST_CNTL2_BLOCK, SMB_HST_CNTL2);

        for (i = 0; i < len; i++) {
                if (rw == I2C_SMBUS_WRITE) {
                        outb_p(data->block[i + 1], SMB_BLK_DAT);
                        error = ali1563_block_start(a);
                        if (error)
                                break;
                } else {
                        error = ali1563_block_start(a);
                        if (error)
                                break;
                        if (i == 0) {
                                len = inb_p(SMB_HST_DAT0);
                                if (len < 1)
                                        len = 1;
                                else if (len > 32)
                                        len = 32;
                        }
                        data->block[i+1] = inb_p(SMB_BLK_DAT);
                }
        }
        /* Do we need this? */
        outb_p(HST_CNTL1_LAST, SMB_HST_CNTL1);
        return error;
}

static s32 ali1563_access(struct i2c_adapter *a, u16 addr,
                          unsigned short flags, char rw, u8 cmd,
                          int size, union i2c_smbus_data *data)
{
        int error = 0;
        int timeout;
        u32 reg;

        for (timeout = ALI1563_MAX_TIMEOUT; timeout; timeout--) {
                reg = inb_p(SMB_HST_STS);
                if (!(reg & HST_STS_BUSY))
                        break;
        }
        if (!timeout)
                dev_warn(&a->dev, "SMBus not idle. HST_STS = %02x\n", reg);
        outb_p(0xff, SMB_HST_STS);

        /* Map the size to what the chip understands */
        switch (size) {
        case I2C_SMBUS_QUICK:
                size = HST_CNTL2_QUICK;
                break;
        case I2C_SMBUS_BYTE:
                size = HST_CNTL2_BYTE;
                break;
        case I2C_SMBUS_BYTE_DATA:
                size = HST_CNTL2_BYTE_DATA;
                break;
        case I2C_SMBUS_WORD_DATA:
                size = HST_CNTL2_WORD_DATA;
                break;
        case I2C_SMBUS_BLOCK_DATA:
                size = HST_CNTL2_BLOCK;
                break;
        default:
                dev_warn(&a->dev, "Unsupported transaction %d\n", size);
                error = -EOPNOTSUPP;
                goto Done;
        }

        outb_p(((addr & 0x7f) << 1) | (rw & 0x01), SMB_HST_ADD);
        outb_p((inb_p(SMB_HST_CNTL2) & ~HST_CNTL2_SIZEMASK) |
               (size << 3), SMB_HST_CNTL2);

        /* Write the command register */

        switch (size) {
        case HST_CNTL2_BYTE:
                if (rw == I2C_SMBUS_WRITE)
                        /* Beware it uses DAT0 register and not CMD! */
                        outb_p(cmd, SMB_HST_DAT0);
                break;
        case HST_CNTL2_BYTE_DATA:
                outb_p(cmd, SMB_HST_CMD);
                if (rw == I2C_SMBUS_WRITE)
                        outb_p(data->byte, SMB_HST_DAT0);
                break;
        case HST_CNTL2_WORD_DATA:
                outb_p(cmd, SMB_HST_CMD);
                if (rw == I2C_SMBUS_WRITE) {
                        outb_p(data->word & 0xff, SMB_HST_DAT0);
                        outb_p((data->word & 0xff00) >> 8, SMB_HST_DAT1);
                }
                break;
        case HST_CNTL2_BLOCK:
                outb_p(cmd, SMB_HST_CMD);
                error = ali1563_block(a, data, rw);
                goto Done;
        }

        error = ali1563_transaction(a, size);
        if (error)
                goto Done;

        if ((rw == I2C_SMBUS_WRITE) || (size == HST_CNTL2_QUICK))
                goto Done;

        switch (size) {
        case HST_CNTL2_BYTE:    /* Result put in SMBHSTDAT0 */
                data->byte = inb_p(SMB_HST_DAT0);
                break;
        case HST_CNTL2_BYTE_DATA:
                data->byte = inb_p(SMB_HST_DAT0);
                break;
        case HST_CNTL2_WORD_DATA:
                data->word = inb_p(SMB_HST_DAT0) + (inb_p(SMB_HST_DAT1) << 8);
                break;
        }
Done:
        return error;
}

static u32 ali1563_func(struct i2c_adapter *a)
{
        return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
            I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
            I2C_FUNC_SMBUS_BLOCK_DATA;
}


static int ali1563_setup(struct pci_dev *dev)
{
        u16 ctrl;

        pci_read_config_word(dev, ALI1563_SMBBA, &ctrl);

        /* SMB I/O Base in high 12 bits and must be aligned with the
         * size of the I/O space. */
        ali1563_smba = ctrl & ~(ALI1563_SMB_IOSIZE - 1);
        if (!ali1563_smba) {
                dev_warn(&dev->dev, "ali1563_smba Uninitialized\n");
                goto Err;
        }

        /* Check if device is enabled */
        if (!(ctrl & ALI1563_SMB_HOSTEN)) {
                dev_warn(&dev->dev, "Host Controller not enabled\n");
                goto Err;
        }
        if (!(ctrl & ALI1563_SMB_IOEN)) {
                dev_warn(&dev->dev, "I/O space not enabled, trying manually\n");
                pci_write_config_word(dev, ALI1563_SMBBA,
                                      ctrl | ALI1563_SMB_IOEN);
                pci_read_config_word(dev, ALI1563_SMBBA, &ctrl);
                if (!(ctrl & ALI1563_SMB_IOEN)) {
                        dev_err(&dev->dev,
                                "I/O space still not enabled, giving up\n");
                        goto Err;
                }
        }

        if (acpi_check_region(ali1563_smba, ALI1563_SMB_IOSIZE,
                              ali1563_pci_driver.name))
                goto Err;

        if (!request_region(ali1563_smba, ALI1563_SMB_IOSIZE,
                            ali1563_pci_driver.name)) {
                dev_err(&dev->dev, "Could not allocate I/O space at 0x%04x\n",
                        ali1563_smba);
                goto Err;
        }
        dev_info(&dev->dev, "Found ALi1563 SMBus at 0x%04x\n", ali1563_smba);

        return 0;
Err:
        return -ENODEV;
}

static void ali1563_shutdown(struct pci_dev *dev)
{
        release_region(ali1563_smba, ALI1563_SMB_IOSIZE);
}

static const struct i2c_algorithm ali1563_algorithm = {
        .smbus_xfer     = ali1563_access,
        .functionality  = ali1563_func,
};

static struct i2c_adapter ali1563_adapter = {
        .owner  = THIS_MODULE,
        .class  = I2C_CLASS_HWMON,
        .algo   = &ali1563_algorithm,
};

static int ali1563_probe(struct pci_dev *dev,
                         const struct pci_device_id *id_table)
{
        int error;

        error = ali1563_setup(dev);
        if (error)
                goto exit;
        ali1563_adapter.dev.parent = &dev->dev;
        snprintf(ali1563_adapter.name, sizeof(ali1563_adapter.name),
                 "SMBus ALi 1563 Adapter @ %04x", ali1563_smba);
        error = i2c_add_adapter(&ali1563_adapter);
        if (error)
                goto exit_shutdown;
        return 0;

exit_shutdown:
        ali1563_shutdown(dev);
exit:
        dev_warn(&dev->dev, "ALi1563 SMBus probe failed (%d)\n", error);
        return error;
}

static void ali1563_remove(struct pci_dev *dev)
{
        i2c_del_adapter(&ali1563_adapter);
        ali1563_shutdown(dev);
}

static const struct pci_device_id ali1563_id_table[] = {
        { PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1563) },
        {},
};

MODULE_DEVICE_TABLE(pci, ali1563_id_table);

static struct pci_driver ali1563_pci_driver = {
        .name           = "ali1563_smbus",
        .id_table       = ali1563_id_table,
        .probe          = ali1563_probe,
        .remove         = ali1563_remove,
};

module_pci_driver(ali1563_pci_driver);

MODULE_DESCRIPTION("i2c driver for the ALi 1563 Southbridge");
MODULE_LICENSE("GPL");