/*
    Copyright (c) 1998 - 2002  Frodo Looijaard <frodol@dds.nl>,
    Philip Edelbrock <phil@netroedge.com>, and Mark D. Studebaker
    <mdsxyz123@yahoo.com>
    Copyright (C) 2007 - 2014  Jean Delvare <jdelvare@suse.de>
    Copyright (C) 2010         Intel Corporation,
                               David Woodhouse <dwmw2@infradead.org>

    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.
*/

/*
 * Supports the following Intel I/O Controller Hubs (ICH):
 *
 *                                      I/O                     Block   I2C
 *                                      region  SMBus   Block   proc.   block
 * Chip name                    PCI ID  size    PEC     buffer  call    read
 * ---------------------------------------------------------------------------
 * 82801AA (ICH)                0x2413  16      no      no      no      no
 * 82801AB (ICH0)               0x2423  16      no      no      no      no
 * 82801BA (ICH2)               0x2443  16      no      no      no      no
 * 82801CA (ICH3)               0x2483  32      soft    no      no      no
 * 82801DB (ICH4)               0x24c3  32      hard    yes     no      no
 * 82801E (ICH5)                0x24d3  32      hard    yes     yes     yes
 * 6300ESB                      0x25a4  32      hard    yes     yes     yes
 * 82801F (ICH6)                0x266a  32      hard    yes     yes     yes
 * 6310ESB/6320ESB              0x269b  32      hard    yes     yes     yes
 * 82801G (ICH7)                0x27da  32      hard    yes     yes     yes
 * 82801H (ICH8)                0x283e  32      hard    yes     yes     yes
 * 82801I (ICH9)                0x2930  32      hard    yes     yes     yes
 * EP80579 (Tolapai)            0x5032  32      hard    yes     yes     yes
 * ICH10                        0x3a30  32      hard    yes     yes     yes
 * ICH10                        0x3a60  32      hard    yes     yes     yes
 * 5/3400 Series (PCH)          0x3b30  32      hard    yes     yes     yes
 * 6 Series (PCH)               0x1c22  32      hard    yes     yes     yes
 * Patsburg (PCH)               0x1d22  32      hard    yes     yes     yes
 * Patsburg (PCH) IDF           0x1d70  32      hard    yes     yes     yes
 * Patsburg (PCH) IDF           0x1d71  32      hard    yes     yes     yes
 * Patsburg (PCH) IDF           0x1d72  32      hard    yes     yes     yes
 * DH89xxCC (PCH)               0x2330  32      hard    yes     yes     yes
 * Panther Point (PCH)          0x1e22  32      hard    yes     yes     yes
 * Lynx Point (PCH)             0x8c22  32      hard    yes     yes     yes
 * Lynx Point-LP (PCH)          0x9c22  32      hard    yes     yes     yes
 * Avoton (SOC)                 0x1f3c  32      hard    yes     yes     yes
 * Wellsburg (PCH)              0x8d22  32      hard    yes     yes     yes
 * Wellsburg (PCH) MS           0x8d7d  32      hard    yes     yes     yes
 * Wellsburg (PCH) MS           0x8d7e  32      hard    yes     yes     yes
 * Wellsburg (PCH) MS           0x8d7f  32      hard    yes     yes     yes
 * Coleto Creek (PCH)           0x23b0  32      hard    yes     yes     yes
 * Wildcat Point (PCH)          0x8ca2  32      hard    yes     yes     yes
 * Wildcat Point-LP (PCH)       0x9ca2  32      hard    yes     yes     yes
 * BayTrail (SOC)               0x0f12  32      hard    yes     yes     yes
 * Sunrise Point-H (PCH)        0xa123  32      hard    yes     yes     yes
 * Sunrise Point-LP (PCH)       0x9d23  32      hard    yes     yes     yes
 * DNV (SOC)                    0x19df  32      hard    yes     yes     yes
 * Broxton (SOC)                0x5ad4  32      hard    yes     yes     yes
 * Lewisburg (PCH)              0xa1a3  32      hard    yes     yes     yes
 * Lewisburg Supersku (PCH)     0xa223  32      hard    yes     yes     yes
 * Kaby Lake PCH-H (PCH)        0xa2a3  32      hard    yes     yes     yes
 * Gemini Lake (SOC)            0x31d4  32      hard    yes     yes     yes
 *
 * Features supported by this driver:
 * Software PEC                         no
 * Hardware PEC                         yes
 * Block buffer                         yes
 * Block process call transaction       no
 * I2C block read transaction           yes (doesn't use the block buffer)
 * Slave mode                           no
 * SMBus Host Notify                    yes
 * Interrupt processing                 yes
 *
 * See the file Documentation/i2c/busses/i2c-i801 for details.
 */

#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/kernel.h>
#include <linux/stddef.h>
#include <linux/delay.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/i2c-smbus.h>
#include <linux/acpi.h>
#include <linux/io.h>
#include <linux/dmi.h>
#include <linux/slab.h>
#include <linux/wait.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/platform_data/itco_wdt.h>
#include <linux/pm_runtime.h>

#if IS_ENABLED(CONFIG_I2C_MUX_GPIO) && defined CONFIG_DMI
#include <linux/gpio.h>
#include <linux/i2c-mux-gpio.h>
#endif

/* I801 SMBus address offsets */
#define SMBHSTSTS(p)    (0 + (p)->smba)
#define SMBHSTCNT(p)    (2 + (p)->smba)
#define SMBHSTCMD(p)    (3 + (p)->smba)
#define SMBHSTADD(p)    (4 + (p)->smba)
#define SMBHSTDAT0(p)   (5 + (p)->smba)
#define SMBHSTDAT1(p)   (6 + (p)->smba)
#define SMBBLKDAT(p)    (7 + (p)->smba)
#define SMBPEC(p)       (8 + (p)->smba)         /* ICH3 and later */
#define SMBAUXSTS(p)    (12 + (p)->smba)        /* ICH4 and later */
#define SMBAUXCTL(p)    (13 + (p)->smba)        /* ICH4 and later */
#define SMBSLVSTS(p)    (16 + (p)->smba)        /* ICH3 and later */
#define SMBSLVCMD(p)    (17 + (p)->smba)        /* ICH3 and later */
#define SMBNTFDADD(p)   (20 + (p)->smba)        /* ICH3 and later */

/* PCI Address Constants */
#define SMBBAR          4
#define SMBPCICTL       0x004
#define SMBPCISTS       0x006
#define SMBHSTCFG       0x040
#define TCOBASE         0x050
#define TCOCTL          0x054

#define ACPIBASE                0x040
#define ACPIBASE_SMI_OFF        0x030
#define ACPICTRL                0x044
#define ACPICTRL_EN             0x080

#define SBREG_BAR               0x10
#define SBREG_SMBCTRL           0xc6000c

/* Host status bits for SMBPCISTS */
#define SMBPCISTS_INTS          BIT(3)

/* Control bits for SMBPCICTL */
#define SMBPCICTL_INTDIS        BIT(10)

/* Host configuration bits for SMBHSTCFG */
#define SMBHSTCFG_HST_EN        BIT(0)
#define SMBHSTCFG_SMB_SMI_EN    BIT(1)
#define SMBHSTCFG_I2C_EN        BIT(2)
#define SMBHSTCFG_SPD_WD        BIT(4)

/* TCO configuration bits for TCOCTL */
#define TCOCTL_EN               BIT(8)

/* Auxiliary status register bits, ICH4+ only */
#define SMBAUXSTS_CRCE          BIT(0)
#define SMBAUXSTS_STCO          BIT(1)

/* Auxiliary control register bits, ICH4+ only */
#define SMBAUXCTL_CRC           BIT(0)
#define SMBAUXCTL_E32B          BIT(1)

/* Other settings */
#define MAX_RETRIES             400

/* I801 command constants */
#define I801_QUICK              0x00
#define I801_BYTE               0x04
#define I801_BYTE_DATA          0x08
#define I801_WORD_DATA          0x0C
#define I801_PROC_CALL          0x10    /* unimplemented */
#define I801_BLOCK_DATA         0x14
#define I801_I2C_BLOCK_DATA     0x18    /* ICH5 and later */

/* I801 Host Control register bits */
#define SMBHSTCNT_INTREN        BIT(0)
#define SMBHSTCNT_KILL          BIT(1)
#define SMBHSTCNT_LAST_BYTE     BIT(5)
#define SMBHSTCNT_START         BIT(6)
#define SMBHSTCNT_PEC_EN        BIT(7)  /* ICH3 and later */

/* I801 Hosts Status register bits */
#define SMBHSTSTS_BYTE_DONE     BIT(7)
#define SMBHSTSTS_INUSE_STS     BIT(6)
#define SMBHSTSTS_SMBALERT_STS  BIT(5)
#define SMBHSTSTS_FAILED        BIT(4)
#define SMBHSTSTS_BUS_ERR       BIT(3)
#define SMBHSTSTS_DEV_ERR       BIT(2)
#define SMBHSTSTS_INTR          BIT(1)
#define SMBHSTSTS_HOST_BUSY     BIT(0)

/* Host Notify Status register bits */
#define SMBSLVSTS_HST_NTFY_STS  BIT(0)

/* Host Notify Command register bits */
#define SMBSLVCMD_HST_NTFY_INTREN       BIT(0)

#define STATUS_ERROR_FLAGS      (SMBHSTSTS_FAILED | SMBHSTSTS_BUS_ERR | \
                                 SMBHSTSTS_DEV_ERR)

#define STATUS_FLAGS            (SMBHSTSTS_BYTE_DONE | SMBHSTSTS_INTR | \
                                 STATUS_ERROR_FLAGS)

/* Older devices have their ID defined in <linux/pci_ids.h> */
#define PCI_DEVICE_ID_INTEL_BAYTRAIL_SMBUS              0x0f12
#define PCI_DEVICE_ID_INTEL_DNV_SMBUS                   0x19df
#define PCI_DEVICE_ID_INTEL_COUGARPOINT_SMBUS           0x1c22
#define PCI_DEVICE_ID_INTEL_PATSBURG_SMBUS              0x1d22
/* Patsburg also has three 'Integrated Device Function' SMBus controllers */
#define PCI_DEVICE_ID_INTEL_PATSBURG_SMBUS_IDF0         0x1d70
#define PCI_DEVICE_ID_INTEL_PATSBURG_SMBUS_IDF1         0x1d71
#define PCI_DEVICE_ID_INTEL_PATSBURG_SMBUS_IDF2         0x1d72
#define PCI_DEVICE_ID_INTEL_PANTHERPOINT_SMBUS          0x1e22
#define PCI_DEVICE_ID_INTEL_AVOTON_SMBUS                0x1f3c
#define PCI_DEVICE_ID_INTEL_BRASWELL_SMBUS              0x2292
#define PCI_DEVICE_ID_INTEL_DH89XXCC_SMBUS              0x2330
#define PCI_DEVICE_ID_INTEL_COLETOCREEK_SMBUS           0x23b0
#define PCI_DEVICE_ID_INTEL_GEMINILAKE_SMBUS            0x31d4
#define PCI_DEVICE_ID_INTEL_5_3400_SERIES_SMBUS         0x3b30
#define PCI_DEVICE_ID_INTEL_BROXTON_SMBUS               0x5ad4
#define PCI_DEVICE_ID_INTEL_LYNXPOINT_SMBUS             0x8c22
#define PCI_DEVICE_ID_INTEL_WILDCATPOINT_SMBUS          0x8ca2
#define PCI_DEVICE_ID_INTEL_WELLSBURG_SMBUS             0x8d22
#define PCI_DEVICE_ID_INTEL_WELLSBURG_SMBUS_MS0         0x8d7d
#define PCI_DEVICE_ID_INTEL_WELLSBURG_SMBUS_MS1         0x8d7e
#define PCI_DEVICE_ID_INTEL_WELLSBURG_SMBUS_MS2         0x8d7f
#define PCI_DEVICE_ID_INTEL_LYNXPOINT_LP_SMBUS          0x9c22
#define PCI_DEVICE_ID_INTEL_WILDCATPOINT_LP_SMBUS       0x9ca2
#define PCI_DEVICE_ID_INTEL_SUNRISEPOINT_LP_SMBUS       0x9d23
#define PCI_DEVICE_ID_INTEL_SUNRISEPOINT_H_SMBUS        0xa123
#define PCI_DEVICE_ID_INTEL_LEWISBURG_SMBUS             0xa1a3
#define PCI_DEVICE_ID_INTEL_LEWISBURG_SSKU_SMBUS        0xa223
#define PCI_DEVICE_ID_INTEL_KABYLAKE_PCH_H_SMBUS        0xa2a3

struct i801_mux_config {
        char *gpio_chip;
        unsigned values[3];
        int n_values;
        unsigned classes[3];
        unsigned gpios[2];              /* Relative to gpio_chip->base */
        int n_gpios;
};

struct i801_priv {
        struct i2c_adapter adapter;
        unsigned long smba;
        unsigned char original_hstcfg;
        unsigned char original_slvcmd;
        struct pci_dev *pci_dev;
        unsigned int features;

        /* isr processing */
        wait_queue_head_t waitq;
        u8 status;

        /* Command state used by isr for byte-by-byte block transactions */
        u8 cmd;
        bool is_read;
        int count;
        int len;
        u8 *data;

#if IS_ENABLED(CONFIG_I2C_MUX_GPIO) && defined CONFIG_DMI
        const struct i801_mux_config *mux_drvdata;
        struct platform_device *mux_pdev;
#endif
        struct platform_device *tco_pdev;

        /*
         * If set to true the host controller registers are reserved for
         * ACPI AML use. Protected by acpi_lock.
         */
        bool acpi_reserved;
        struct mutex acpi_lock;
};

#define FEATURE_SMBUS_PEC       BIT(0)
#define FEATURE_BLOCK_BUFFER    BIT(1)
#define FEATURE_BLOCK_PROC      BIT(2)
#define FEATURE_I2C_BLOCK_READ  BIT(3)
#define FEATURE_IRQ             BIT(4)
#define FEATURE_HOST_NOTIFY     BIT(5)
/* Not really a feature, but it's convenient to handle it as such */
#define FEATURE_IDF             BIT(15)
#define FEATURE_TCO             BIT(16)

static const char *i801_feature_names[] = {
        "SMBus PEC",
        "Block buffer",
        "Block process call",
        "I2C block read",
        "Interrupt",
        "SMBus Host Notify",
};

static unsigned int disable_features;
module_param(disable_features, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(disable_features, "Disable selected driver features:\n"
        "\t\t  0x01  disable SMBus PEC\n"
        "\t\t  0x02  disable the block buffer\n"
        "\t\t  0x08  disable the I2C block read functionality\n"
        "\t\t  0x10  don't use interrupts\n"
        "\t\t  0x20  disable SMBus Host Notify ");

/* Make sure the SMBus host is ready to start transmitting.
   Return 0 if it is, -EBUSY if it is not. */
static int i801_check_pre(struct i801_priv *priv)
{
        int status;

        status = inb_p(SMBHSTSTS(priv));
        if (status & SMBHSTSTS_HOST_BUSY) {
                dev_err(&priv->pci_dev->dev, "SMBus is busy, can't use it!\n");
                return -EBUSY;
        }

        status &= STATUS_FLAGS;
        if (status) {
                dev_dbg(&priv->pci_dev->dev, "Clearing status flags (%02x)\n",
                        status);
                outb_p(status, SMBHSTSTS(priv));
                status = inb_p(SMBHSTSTS(priv)) & STATUS_FLAGS;
                if (status) {
                        dev_err(&priv->pci_dev->dev,
                                "Failed clearing status flags (%02x)\n",
                                status);
                        return -EBUSY;
                }
        }

        /*
         * Clear CRC status if needed.
         * During normal operation, i801_check_post() takes care
         * of it after every operation.  We do it here only in case
         * the hardware was already in this state when the driver
         * started.
         */
        if (priv->features & FEATURE_SMBUS_PEC) {
                status = inb_p(SMBAUXSTS(priv)) & SMBAUXSTS_CRCE;
                if (status) {
                        dev_dbg(&priv->pci_dev->dev,
                                "Clearing aux status flags (%02x)\n", status);
                        outb_p(status, SMBAUXSTS(priv));
                        status = inb_p(SMBAUXSTS(priv)) & SMBAUXSTS_CRCE;
                        if (status) {
                                dev_err(&priv->pci_dev->dev,
                                        "Failed clearing aux status flags (%02x)\n",
                                        status);
                                return -EBUSY;
                        }
                }
        }

        return 0;
}

/*
 * Convert the status register to an error code, and clear it.
 * Note that status only contains the bits we want to clear, not the
 * actual register value.
 */
static int i801_check_post(struct i801_priv *priv, int status)
{
        int result = 0;

        /*
         * If the SMBus is still busy, we give up
         * Note: This timeout condition only happens when using polling
         * transactions.  For interrupt operation, NAK/timeout is indicated by
         * DEV_ERR.
         */
        if (unlikely(status < 0)) {
                dev_err(&priv->pci_dev->dev, "Transaction timeout\n");
                /* try to stop the current command */
                dev_dbg(&priv->pci_dev->dev, "Terminating the current operation\n");
                outb_p(inb_p(SMBHSTCNT(priv)) | SMBHSTCNT_KILL,
                       SMBHSTCNT(priv));
                usleep_range(1000, 2000);
                outb_p(inb_p(SMBHSTCNT(priv)) & (~SMBHSTCNT_KILL),
                       SMBHSTCNT(priv));

                /* Check if it worked */
                status = inb_p(SMBHSTSTS(priv));
                if ((status & SMBHSTSTS_HOST_BUSY) ||
                    !(status & SMBHSTSTS_FAILED))
                        dev_err(&priv->pci_dev->dev,
                                "Failed terminating the transaction\n");
                outb_p(STATUS_FLAGS, SMBHSTSTS(priv));
                return -ETIMEDOUT;
        }

        if (status & SMBHSTSTS_FAILED) {
                result = -EIO;
                dev_err(&priv->pci_dev->dev, "Transaction failed\n");
        }
        if (status & SMBHSTSTS_DEV_ERR) {
                /*
                 * This may be a PEC error, check and clear it.
                 *
                 * AUXSTS is handled differently from HSTSTS.
                 * For HSTSTS, i801_isr() or i801_wait_intr()
                 * has already cleared the error bits in hardware,
                 * and we are passed a copy of the original value
                 * in "status".
                 * For AUXSTS, the hardware register is left
                 * for us to handle here.
                 * This is asymmetric, slightly iffy, but safe,
                 * since all this code is serialized and the CRCE
                 * bit is harmless as long as it's cleared before
                 * the next operation.
                 */
                if ((priv->features & FEATURE_SMBUS_PEC) &&
                    (inb_p(SMBAUXSTS(priv)) & SMBAUXSTS_CRCE)) {
                        outb_p(SMBAUXSTS_CRCE, SMBAUXSTS(priv));
                        result = -EBADMSG;
                        dev_dbg(&priv->pci_dev->dev, "PEC error\n");
                } else {
                        result = -ENXIO;
                        dev_dbg(&priv->pci_dev->dev, "No response\n");
                }
        }
        if (status & SMBHSTSTS_BUS_ERR) {
                result = -EAGAIN;
                dev_dbg(&priv->pci_dev->dev, "Lost arbitration\n");
        }

        /* Clear status flags except BYTE_DONE, to be cleared by caller */
        outb_p(status, SMBHSTSTS(priv));

        return result;
}

/* Wait for BUSY being cleared and either INTR or an error flag being set */
static int i801_wait_intr(struct i801_priv *priv)
{
        int timeout = 0;
        int status;

        /* We will always wait for a fraction of a second! */
        do {
                usleep_range(250, 500);
                status = inb_p(SMBHSTSTS(priv));
        } while (((status & SMBHSTSTS_HOST_BUSY) ||
                  !(status & (STATUS_ERROR_FLAGS | SMBHSTSTS_INTR))) &&
                 (timeout++ < MAX_RETRIES));

        if (timeout > MAX_RETRIES) {
                dev_dbg(&priv->pci_dev->dev, "INTR Timeout!\n");
                return -ETIMEDOUT;
        }
        return status & (STATUS_ERROR_FLAGS | SMBHSTSTS_INTR);
}

/* Wait for either BYTE_DONE or an error flag being set */
static int i801_wait_byte_done(struct i801_priv *priv)
{
        int timeout = 0;
        int status;

        /* We will always wait for a fraction of a second! */
        do {
                usleep_range(250, 500);
                status = inb_p(SMBHSTSTS(priv));
        } while (!(status & (STATUS_ERROR_FLAGS | SMBHSTSTS_BYTE_DONE)) &&
                 (timeout++ < MAX_RETRIES));

        if (timeout > MAX_RETRIES) {
                dev_dbg(&priv->pci_dev->dev, "BYTE_DONE Timeout!\n");
                return -ETIMEDOUT;
        }
        return status & STATUS_ERROR_FLAGS;
}

static int i801_transaction(struct i801_priv *priv, int xact)
{
        int status;
        int result;
        const struct i2c_adapter *adap = &priv->adapter;

        result = i801_check_pre(priv);
        if (result < 0)
                return result;

        if (priv->features & FEATURE_IRQ) {
                outb_p(xact | SMBHSTCNT_INTREN | SMBHSTCNT_START,
                       SMBHSTCNT(priv));
                result = wait_event_timeout(priv->waitq,
                                            (status = priv->status),
                                            adap->timeout);
                if (!result) {
                        status = -ETIMEDOUT;
                        dev_warn(&priv->pci_dev->dev,
                                 "Timeout waiting for interrupt!\n");
                }
                priv->status = 0;
                return i801_check_post(priv, status);
        }

        /* the current contents of SMBHSTCNT can be overwritten, since PEC,
         * SMBSCMD are passed in xact */
        outb_p(xact | SMBHSTCNT_START, SMBHSTCNT(priv));

        status = i801_wait_intr(priv);
        return i801_check_post(priv, status);
}

static int i801_block_transaction_by_block(struct i801_priv *priv,
                                           union i2c_smbus_data *data,
                                           char read_write, int hwpec)
{
        int i, len;
        int status;

        inb_p(SMBHSTCNT(priv)); /* reset the data buffer index */

        /* Use 32-byte buffer to process this transaction */
        if (read_write == I2C_SMBUS_WRITE) {
                len = data->block[0];
                outb_p(len, SMBHSTDAT0(priv));
                for (i = 0; i < len; i++)
                        outb_p(data->block[i+1], SMBBLKDAT(priv));
        }

        status = i801_transaction(priv, I801_BLOCK_DATA |
                                  (hwpec ? SMBHSTCNT_PEC_EN : 0));
        if (status)
                return status;

        if (read_write == I2C_SMBUS_READ) {
                len = inb_p(SMBHSTDAT0(priv));
                if (len < 1 || len > I2C_SMBUS_BLOCK_MAX)
                        return -EPROTO;

                data->block[0] = len;
                for (i = 0; i < len; i++)
                        data->block[i + 1] = inb_p(SMBBLKDAT(priv));
        }
        return 0;
}

static void i801_isr_byte_done(struct i801_priv *priv)
{
        if (priv->is_read) {
                /* For SMBus block reads, length is received with first byte */
                if (((priv->cmd & 0x1c) == I801_BLOCK_DATA) &&
                    (priv->count == 0)) {
                        priv->len = inb_p(SMBHSTDAT0(priv));
                        if (priv->len < 1 || priv->len > I2C_SMBUS_BLOCK_MAX) {
                                dev_err(&priv->pci_dev->dev,
                                        "Illegal SMBus block read size %d\n",
                                        priv->len);
                                /* FIXME: Recover */
                                priv->len = I2C_SMBUS_BLOCK_MAX;
                        } else {
                                dev_dbg(&priv->pci_dev->dev,
                                        "SMBus block read size is %d\n",
                                        priv->len);
                        }
                        priv->data[-1] = priv->len;
                }

                /* Read next byte */
                if (priv->count < priv->len)
                        priv->data[priv->count++] = inb(SMBBLKDAT(priv));
                else
                        dev_dbg(&priv->pci_dev->dev,
                                "Discarding extra byte on block read\n");

                /* Set LAST_BYTE for last byte of read transaction */
                if (priv->count == priv->len - 1)
                        outb_p(priv->cmd | SMBHSTCNT_LAST_BYTE,
                               SMBHSTCNT(priv));
        } else if (priv->count < priv->len - 1) {
                /* Write next byte, except for IRQ after last byte */
                outb_p(priv->data[++priv->count], SMBBLKDAT(priv));
        }

        /* Clear BYTE_DONE to continue with next byte */
        outb_p(SMBHSTSTS_BYTE_DONE, SMBHSTSTS(priv));
}

static irqreturn_t i801_host_notify_isr(struct i801_priv *priv)
{
        unsigned short addr;

        addr = inb_p(SMBNTFDADD(priv)) >> 1;

        /*
         * With the tested platforms, reading SMBNTFDDAT (22 + (p)->smba)
         * always returns 0. Our current implementation doesn't provide
         * data, so we just ignore it.
         */
        i2c_handle_smbus_host_notify(&priv->adapter, addr);

        /* clear Host Notify bit and return */
        outb_p(SMBSLVSTS_HST_NTFY_STS, SMBSLVSTS(priv));
        return IRQ_HANDLED;
}

/*
 * There are three kinds of interrupts:
 *
 * 1) i801 signals transaction completion with one of these interrupts:
 *      INTR - Success
 *      DEV_ERR - Invalid command, NAK or communication timeout
 *      BUS_ERR - SMI# transaction collision
 *      FAILED - transaction was canceled due to a KILL request
 *    When any of these occur, update ->status and wake up the waitq.
 *    ->status must be cleared before kicking off the next transaction.
 *
 * 2) For byte-by-byte (I2C read/write) transactions, one BYTE_DONE interrupt
 *    occurs for each byte of a byte-by-byte to prepare the next byte.
 *
 * 3) Host Notify interrupts
 */
static irqreturn_t i801_isr(int irq, void *dev_id)
{
        struct i801_priv *priv = dev_id;
        u16 pcists;
        u8 status;

        /* Confirm this is our interrupt */
        pci_read_config_word(priv->pci_dev, SMBPCISTS, &pcists);
        if (!(pcists & SMBPCISTS_INTS))
                return IRQ_NONE;

        if (priv->features & FEATURE_HOST_NOTIFY) {
                status = inb_p(SMBSLVSTS(priv));
                if (status & SMBSLVSTS_HST_NTFY_STS)
                        return i801_host_notify_isr(priv);
        }

        status = inb_p(SMBHSTSTS(priv));
        if (status & SMBHSTSTS_BYTE_DONE)
                i801_isr_byte_done(priv);

        /*
         * Clear irq sources and report transaction result.
         * ->status must be cleared before the next transaction is started.
         */
        status &= SMBHSTSTS_INTR | STATUS_ERROR_FLAGS;
        if (status) {
                outb_p(status, SMBHSTSTS(priv));
                priv->status = status;
                wake_up(&priv->waitq);
        }

        return IRQ_HANDLED;
}

/*
 * For "byte-by-byte" block transactions:
 *   I2C write uses cmd=I801_BLOCK_DATA, I2C_EN=1
 *   I2C read uses cmd=I801_I2C_BLOCK_DATA
 */
static int i801_block_transaction_byte_by_byte(struct i801_priv *priv,
                                               union i2c_smbus_data *data,
                                               char read_write, int command,
                                               int hwpec)
{
        int i, len;
        int smbcmd;
        int status;
        int result;
        const struct i2c_adapter *adap = &priv->adapter;

        result = i801_check_pre(priv);
        if (result < 0)
                return result;

        len = data->block[0];

        if (read_write == I2C_SMBUS_WRITE) {
                outb_p(len, SMBHSTDAT0(priv));
                outb_p(data->block[1], SMBBLKDAT(priv));
        }

        if (command == I2C_SMBUS_I2C_BLOCK_DATA &&
            read_write == I2C_SMBUS_READ)
                smbcmd = I801_I2C_BLOCK_DATA;
        else
                smbcmd = I801_BLOCK_DATA;

        if (priv->features & FEATURE_IRQ) {
                priv->is_read = (read_write == I2C_SMBUS_READ);
                if (len == 1 && priv->is_read)
                        smbcmd |= SMBHSTCNT_LAST_BYTE;
                priv->cmd = smbcmd | SMBHSTCNT_INTREN;
                priv->len = len;
                priv->count = 0;
                priv->data = &data->block[1];

                outb_p(priv->cmd | SMBHSTCNT_START, SMBHSTCNT(priv));
                result = wait_event_timeout(priv->waitq,
                                            (status = priv->status),
                                            adap->timeout);
                if (!result) {
                        status = -ETIMEDOUT;
                        dev_warn(&priv->pci_dev->dev,
                                 "Timeout waiting for interrupt!\n");
                }
                priv->status = 0;
                return i801_check_post(priv, status);
        }

        for (i = 1; i <= len; i++) {
                if (i == len && read_write == I2C_SMBUS_READ)
                        smbcmd |= SMBHSTCNT_LAST_BYTE;
                outb_p(smbcmd, SMBHSTCNT(priv));

                if (i == 1)
                        outb_p(inb(SMBHSTCNT(priv)) | SMBHSTCNT_START,
                               SMBHSTCNT(priv));

                status = i801_wait_byte_done(priv);
                if (status)
                        goto exit;

                if (i == 1 && read_write == I2C_SMBUS_READ
                 && command != I2C_SMBUS_I2C_BLOCK_DATA) {
                        len = inb_p(SMBHSTDAT0(priv));
                        if (len < 1 || len > I2C_SMBUS_BLOCK_MAX) {
                                dev_err(&priv->pci_dev->dev,
                                        "Illegal SMBus block read size %d\n",
                                        len);
                                /* Recover */
                                while (inb_p(SMBHSTSTS(priv)) &
                                       SMBHSTSTS_HOST_BUSY)
                                        outb_p(SMBHSTSTS_BYTE_DONE,
                                               SMBHSTSTS(priv));
                                outb_p(SMBHSTSTS_INTR, SMBHSTSTS(priv));
                                return -EPROTO;
                        }
                        data->block[0] = len;
                }

                /* Retrieve/store value in SMBBLKDAT */
                if (read_write == I2C_SMBUS_READ)
                        data->block[i] = inb_p(SMBBLKDAT(priv));
                if (read_write == I2C_SMBUS_WRITE && i+1 <= len)
                        outb_p(data->block[i+1], SMBBLKDAT(priv));

                /* signals SMBBLKDAT ready */
                outb_p(SMBHSTSTS_BYTE_DONE, SMBHSTSTS(priv));
        }

        status = i801_wait_intr(priv);
exit:
        return i801_check_post(priv, status);
}

static int i801_set_block_buffer_mode(struct i801_priv *priv)
{
        outb_p(inb_p(SMBAUXCTL(priv)) | SMBAUXCTL_E32B, SMBAUXCTL(priv));
        if ((inb_p(SMBAUXCTL(priv)) & SMBAUXCTL_E32B) == 0)
                return -EIO;
        return 0;
}

/* Block transaction function */
static int i801_block_transaction(struct i801_priv *priv,
                                  union i2c_smbus_data *data, char read_write,
                                  int command, int hwpec)
{
        int result = 0;
        unsigned char hostc;

        if (command == I2C_SMBUS_I2C_BLOCK_DATA) {
                if (read_write == I2C_SMBUS_WRITE) {
                        /* set I2C_EN bit in configuration register */
                        pci_read_config_byte(priv->pci_dev, SMBHSTCFG, &hostc);
                        pci_write_config_byte(priv->pci_dev, SMBHSTCFG,
                                              hostc | SMBHSTCFG_I2C_EN);
                } else if (!(priv->features & FEATURE_I2C_BLOCK_READ)) {
                        dev_err(&priv->pci_dev->dev,
                                "I2C block read is unsupported!\n");
                        return -EOPNOTSUPP;
                }
        }

        if (read_write == I2C_SMBUS_WRITE
         || command == I2C_SMBUS_I2C_BLOCK_DATA) {
                if (data->block[0] < 1)
                        data->block[0] = 1;
                if (data->block[0] > I2C_SMBUS_BLOCK_MAX)
                        data->block[0] = I2C_SMBUS_BLOCK_MAX;
        } else {
                data->block[0] = 32;    /* max for SMBus block reads */
        }

        /* Experience has shown that the block buffer can only be used for
           SMBus (not I2C) block transactions, even though the datasheet
           doesn't mention this limitation. */
        if ((priv->features & FEATURE_BLOCK_BUFFER)
         && command != I2C_SMBUS_I2C_BLOCK_DATA
         && i801_set_block_buffer_mode(priv) == 0)
                result = i801_block_transaction_by_block(priv, data,
                                                         read_write, hwpec);
        else
                result = i801_block_transaction_byte_by_byte(priv, data,
                                                             read_write,
                                                             command, hwpec);

        if (command == I2C_SMBUS_I2C_BLOCK_DATA
         && read_write == I2C_SMBUS_WRITE) {
                /* restore saved configuration register value */
                pci_write_config_byte(priv->pci_dev, SMBHSTCFG, hostc);
        }
        return result;
}

/* Return negative errno on error. */
static s32 i801_access(struct i2c_adapter *adap, u16 addr,
                       unsigned short flags, char read_write, u8 command,
                       int size, union i2c_smbus_data *data)
{
        int hwpec;
        int block = 0;
        int ret = 0, xact = 0;
        struct i801_priv *priv = i2c_get_adapdata(adap);

        mutex_lock(&priv->acpi_lock);
        if (priv->acpi_reserved) {
                mutex_unlock(&priv->acpi_lock);
                return -EBUSY;
        }

        pm_runtime_get_sync(&priv->pci_dev->dev);

        hwpec = (priv->features & FEATURE_SMBUS_PEC) && (flags & I2C_CLIENT_PEC)
                && size != I2C_SMBUS_QUICK
                && size != I2C_SMBUS_I2C_BLOCK_DATA;

        switch (size) {
        case I2C_SMBUS_QUICK:
                outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
                       SMBHSTADD(priv));
                xact = I801_QUICK;
                break;
        case I2C_SMBUS_BYTE:
                outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
                       SMBHSTADD(priv));
                if (read_write == I2C_SMBUS_WRITE)
                        outb_p(command, SMBHSTCMD(priv));
                xact = I801_BYTE;
                break;
        case I2C_SMBUS_BYTE_DATA:
                outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
                       SMBHSTADD(priv));
                outb_p(command, SMBHSTCMD(priv));
                if (read_write == I2C_SMBUS_WRITE)
                        outb_p(data->byte, SMBHSTDAT0(priv));
                xact = I801_BYTE_DATA;
                break;
        case I2C_SMBUS_WORD_DATA:
                outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
                       SMBHSTADD(priv));
                outb_p(command, SMBHSTCMD(priv));
                if (read_write == I2C_SMBUS_WRITE) {
                        outb_p(data->word & 0xff, SMBHSTDAT0(priv));
                        outb_p((data->word & 0xff00) >> 8, SMBHSTDAT1(priv));
                }
                xact = I801_WORD_DATA;
                break;
        case I2C_SMBUS_BLOCK_DATA:
                outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
                       SMBHSTADD(priv));
                outb_p(command, SMBHSTCMD(priv));
                block = 1;
                break;
        case I2C_SMBUS_I2C_BLOCK_DATA:
                /*
                 * NB: page 240 of ICH5 datasheet shows that the R/#W
                 * bit should be cleared here, even when reading.
                 * However if SPD Write Disable is set (Lynx Point and later),
                 * the read will fail if we don't set the R/#W bit.
                 */
                outb_p(((addr & 0x7f) << 1) |
                       ((priv->original_hstcfg & SMBHSTCFG_SPD_WD) ?
                        (read_write & 0x01) : 0),
                       SMBHSTADD(priv));
                if (read_write == I2C_SMBUS_READ) {
                        /* NB: page 240 of ICH5 datasheet also shows
                         * that DATA1 is the cmd field when reading */
                        outb_p(command, SMBHSTDAT1(priv));
                } else
                        outb_p(command, SMBHSTCMD(priv));
                block = 1;
                break;
        default:
                dev_err(&priv->pci_dev->dev, "Unsupported transaction %d\n",
                        size);
                ret = -EOPNOTSUPP;
                goto out;
        }

        if (hwpec)      /* enable/disable hardware PEC */
                outb_p(inb_p(SMBAUXCTL(priv)) | SMBAUXCTL_CRC, SMBAUXCTL(priv));
        else
                outb_p(inb_p(SMBAUXCTL(priv)) & (~SMBAUXCTL_CRC),
                       SMBAUXCTL(priv));

        if (block)
                ret = i801_block_transaction(priv, data, read_write, size,
                                             hwpec);
        else
                ret = i801_transaction(priv, xact);

        /* Some BIOSes don't like it when PEC is enabled at reboot or resume
           time, so we forcibly disable it after every transaction. Turn off
           E32B for the same reason. */
        if (hwpec || block)
                outb_p(inb_p(SMBAUXCTL(priv)) &
                       ~(SMBAUXCTL_CRC | SMBAUXCTL_E32B), SMBAUXCTL(priv));

        if (block)
                goto out;
        if (ret)
                goto out;
        if ((read_write == I2C_SMBUS_WRITE) || (xact == I801_QUICK))
                goto out;

        switch (xact & 0x7f) {
        case I801_BYTE: /* Result put in SMBHSTDAT0 */
        case I801_BYTE_DATA:
                data->byte = inb_p(SMBHSTDAT0(priv));
                break;
        case I801_WORD_DATA:
                data->word = inb_p(SMBHSTDAT0(priv)) +
                             (inb_p(SMBHSTDAT1(priv)) << 8);
                break;
        }

out:
        pm_runtime_mark_last_busy(&priv->pci_dev->dev);
        pm_runtime_put_autosuspend(&priv->pci_dev->dev);
        mutex_unlock(&priv->acpi_lock);
        return ret;
}


static u32 i801_func(struct i2c_adapter *adapter)
{
        struct i801_priv *priv = i2c_get_adapdata(adapter);

        return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
               I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
               I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_WRITE_I2C_BLOCK |
               ((priv->features & FEATURE_SMBUS_PEC) ? I2C_FUNC_SMBUS_PEC : 0) |
               ((priv->features & FEATURE_I2C_BLOCK_READ) ?
                I2C_FUNC_SMBUS_READ_I2C_BLOCK : 0) |
               ((priv->features & FEATURE_HOST_NOTIFY) ?
                I2C_FUNC_SMBUS_HOST_NOTIFY : 0);
}

static void i801_enable_host_notify(struct i2c_adapter *adapter)
{
        struct i801_priv *priv = i2c_get_adapdata(adapter);

        if (!(priv->features & FEATURE_HOST_NOTIFY))
                return;

        priv->original_slvcmd = inb_p(SMBSLVCMD(priv));

        if (!(SMBSLVCMD_HST_NTFY_INTREN & priv->original_slvcmd))
                outb_p(SMBSLVCMD_HST_NTFY_INTREN | priv->original_slvcmd,
                       SMBSLVCMD(priv));

        /* clear Host Notify bit to allow a new notification */
        outb_p(SMBSLVSTS_HST_NTFY_STS, SMBSLVSTS(priv));
}

static void i801_disable_host_notify(struct i801_priv *priv)
{
        if (!(priv->features & FEATURE_HOST_NOTIFY))
                return;

        outb_p(priv->original_slvcmd, SMBSLVCMD(priv));
}

static const struct i2c_algorithm smbus_algorithm = {
        .smbus_xfer     = i801_access,
        .functionality  = i801_func,
};

static const struct pci_device_id i801_ids[] = {
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801AA_3) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801AB_3) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801BA_2) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801CA_3) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801DB_3) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801EB_3) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB_4) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ICH6_16) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ICH7_17) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB2_17) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ICH8_5) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ICH9_6) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_EP80579_1) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ICH10_4) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ICH10_5) },

        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_5_3400_SERIES_SMBUS) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_COUGARPOINT_SMBUS) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_PATSBURG_SMBUS) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_PATSBURG_SMBUS_IDF0) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_PATSBURG_SMBUS_IDF1) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_PATSBURG_SMBUS_IDF2) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_DH89XXCC_SMBUS) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_PANTHERPOINT_SMBUS) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_LYNXPOINT_SMBUS) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_LYNXPOINT_LP_SMBUS) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_AVOTON_SMBUS) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_WELLSBURG_SMBUS) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_WELLSBURG_SMBUS_MS0) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_WELLSBURG_SMBUS_MS1) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_WELLSBURG_SMBUS_MS2) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_COLETOCREEK_SMBUS) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_GEMINILAKE_SMBUS) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_WILDCATPOINT_SMBUS) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_WILDCATPOINT_LP_SMBUS) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_BAYTRAIL_SMBUS) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_BRASWELL_SMBUS) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_SUNRISEPOINT_H_SMBUS) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_SUNRISEPOINT_LP_SMBUS) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_DNV_SMBUS) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_BROXTON_SMBUS) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_LEWISBURG_SMBUS) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_LEWISBURG_SSKU_SMBUS) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_KABYLAKE_PCH_H_SMBUS) },
        { 0, }
};

MODULE_DEVICE_TABLE(pci, i801_ids);

#if defined CONFIG_X86 && defined CONFIG_DMI
static unsigned char apanel_addr;

/* Scan the system ROM for the signature "FJKEYINF" */
static __init const void __iomem *bios_signature(const void __iomem *bios)
{
        ssize_t offset;
        const unsigned char signature[] = "FJKEYINF";

        for (offset = 0; offset < 0x10000; offset += 0x10) {
                if (check_signature(bios + offset, signature,
                                    sizeof(signature)-1))
                        return bios + offset;
        }
        return NULL;
}

static void __init input_apanel_init(void)
{
        void __iomem *bios;
        const void __iomem *p;

        bios = ioremap(0xF0000, 0x10000); /* Can't fail */
        p = bios_signature(bios);
        if (p) {
                /* just use the first address */
                apanel_addr = readb(p + 8 + 3) >> 1;
        }
        iounmap(bios);
}

struct dmi_onboard_device_info {
        const char *name;
        u8 type;
        unsigned short i2c_addr;
        const char *i2c_type;
};

static const struct dmi_onboard_device_info dmi_devices[] = {
        { "Syleus", DMI_DEV_TYPE_OTHER, 0x73, "fscsyl" },
        { "Hermes", DMI_DEV_TYPE_OTHER, 0x73, "fscher" },
        { "Hades",  DMI_DEV_TYPE_OTHER, 0x73, "fschds" },
};

static void dmi_check_onboard_device(u8 type, const char *name,
                                     struct i2c_adapter *adap)
{
        int i;
        struct i2c_board_info info;

        for (i = 0; i < ARRAY_SIZE(dmi_devices); i++) {
                /* & ~0x80, ignore enabled/disabled bit */
                if ((type & ~0x80) != dmi_devices[i].type)
                        continue;
                if (strcasecmp(name, dmi_devices[i].name))
                        continue;

                memset(&info, 0, sizeof(struct i2c_board_info));
                info.addr = dmi_devices[i].i2c_addr;
                strlcpy(info.type, dmi_devices[i].i2c_type, I2C_NAME_SIZE);
                i2c_new_device(adap, &info);
                break;
        }
}

/* We use our own function to check for onboard devices instead of
   dmi_find_device() as some buggy BIOS's have the devices we are interested
   in marked as disabled */
static void dmi_check_onboard_devices(const struct dmi_header *dm, void *adap)
{
        int i, count;

        if (dm->type != 10)
                return;

        count = (dm->length - sizeof(struct dmi_header)) / 2;
        for (i = 0; i < count; i++) {
                const u8 *d = (char *)(dm + 1) + (i * 2);
                const char *name = ((char *) dm) + dm->length;
                u8 type = d[0];
                u8 s = d[1];

                if (!s)
                        continue;
                s--;
                while (s > 0 && name[0]) {
                        name += strlen(name) + 1;
                        s--;
                }
                if (name[0] == 0) /* Bogus string reference */
                        continue;

                dmi_check_onboard_device(type, name, adap);
        }
}

/* Register optional slaves */
static void i801_probe_optional_slaves(struct i801_priv *priv)
{
        /* Only register slaves on main SMBus channel */
        if (priv->features & FEATURE_IDF)
                return;

        if (apanel_addr) {
                struct i2c_board_info info;

                memset(&info, 0, sizeof(struct i2c_board_info));
                info.addr = apanel_addr;
                strlcpy(info.type, "fujitsu_apanel", I2C_NAME_SIZE);
                i2c_new_device(&priv->adapter, &info);
        }

        if (dmi_name_in_vendors("FUJITSU"))
                dmi_walk(dmi_check_onboard_devices, &priv->adapter);
}
#else
static void __init input_apanel_init(void) {}
static void i801_probe_optional_slaves(struct i801_priv *priv) {}
#endif  /* CONFIG_X86 && CONFIG_DMI */

#if IS_ENABLED(CONFIG_I2C_MUX_GPIO) && defined CONFIG_DMI
static struct i801_mux_config i801_mux_config_asus_z8_d12 = {
        .gpio_chip = "gpio_ich",
        .values = { 0x02, 0x03 },
        .n_values = 2,
        .classes = { I2C_CLASS_SPD, I2C_CLASS_SPD },
        .gpios = { 52, 53 },
        .n_gpios = 2,
};

static struct i801_mux_config i801_mux_config_asus_z8_d18 = {
        .gpio_chip = "gpio_ich",
        .values = { 0x02, 0x03, 0x01 },
        .n_values = 3,
        .classes = { I2C_CLASS_SPD, I2C_CLASS_SPD, I2C_CLASS_SPD },
        .gpios = { 52, 53 },
        .n_gpios = 2,
};

static const struct dmi_system_id mux_dmi_table[] = {
        {
                .matches = {
                        DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
                        DMI_MATCH(DMI_BOARD_NAME, "Z8NA-D6(C)"),
                },
                .driver_data = &i801_mux_config_asus_z8_d12,
        },
        {
                .matches = {
                        DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
                        DMI_MATCH(DMI_BOARD_NAME, "Z8P(N)E-D12(X)"),
                },
                .driver_data = &i801_mux_config_asus_z8_d12,
        },
        {
                .matches = {
                        DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
                        DMI_MATCH(DMI_BOARD_NAME, "Z8NH-D12"),
                },
                .driver_data = &i801_mux_config_asus_z8_d12,
        },
        {
                .matches = {
                        DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
                        DMI_MATCH(DMI_BOARD_NAME, "Z8PH-D12/IFB"),
                },
                .driver_data = &i801_mux_config_asus_z8_d12,
        },
        {
                .matches = {
                        DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
                        DMI_MATCH(DMI_BOARD_NAME, "Z8NR-D12"),
                },
                .driver_data = &i801_mux_config_asus_z8_d12,
        },
        {
                .matches = {
                        DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
                        DMI_MATCH(DMI_BOARD_NAME, "Z8P(N)H-D12"),
                },
                .driver_data = &i801_mux_config_asus_z8_d12,
        },
        {
                .matches = {
                        DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
                        DMI_MATCH(DMI_BOARD_NAME, "Z8PG-D18"),
                },
                .driver_data = &i801_mux_config_asus_z8_d18,
        },
        {
                .matches = {
                        DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
                        DMI_MATCH(DMI_BOARD_NAME, "Z8PE-D18"),
                },
                .driver_data = &i801_mux_config_asus_z8_d18,
        },
        {
                .matches = {
                        DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
                        DMI_MATCH(DMI_BOARD_NAME, "Z8PS-D12"),
                },
                .driver_data = &i801_mux_config_asus_z8_d12,
        },
        { }
};

/* Setup multiplexing if needed */
static int i801_add_mux(struct i801_priv *priv)
{
        struct device *dev = &priv->adapter.dev;
        const struct i801_mux_config *mux_config;
        struct i2c_mux_gpio_platform_data gpio_data;
        int err;

        if (!priv->mux_drvdata)
                return 0;
        mux_config = priv->mux_drvdata;

        /* Prepare the platform data */
        memset(&gpio_data, 0, sizeof(struct i2c_mux_gpio_platform_data));
        gpio_data.parent = priv->adapter.nr;
        gpio_data.values = mux_config->values;
        gpio_data.n_values = mux_config->n_values;
        gpio_data.classes = mux_config->classes;
        gpio_data.gpio_chip = mux_config->gpio_chip;
        gpio_data.gpios = mux_config->gpios;
        gpio_data.n_gpios = mux_config->n_gpios;
        gpio_data.idle = I2C_MUX_GPIO_NO_IDLE;

        /* Register the mux device */
        priv->mux_pdev = platform_device_register_data(dev, "i2c-mux-gpio",
                                PLATFORM_DEVID_AUTO, &gpio_data,
                                sizeof(struct i2c_mux_gpio_platform_data));
        if (IS_ERR(priv->mux_pdev)) {
                err = PTR_ERR(priv->mux_pdev);
                priv->mux_pdev = NULL;
                dev_err(dev, "Failed to register i2c-mux-gpio device\n");
                return err;
        }

        return 0;
}

static void i801_del_mux(struct i801_priv *priv)
{
        if (priv->mux_pdev)
                platform_device_unregister(priv->mux_pdev);
}

static unsigned int i801_get_adapter_class(struct i801_priv *priv)
{
        const struct dmi_system_id *id;
        const struct i801_mux_config *mux_config;
        unsigned int class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
        int i;

        id = dmi_first_match(mux_dmi_table);
        if (id) {
                /* Remove branch classes from trunk */
                mux_config = id->driver_data;
                for (i = 0; i < mux_config->n_values; i++)
                        class &= ~mux_config->classes[i];

                /* Remember for later */
                priv->mux_drvdata = mux_config;
        }

        return class;
}
#else
static inline int i801_add_mux(struct i801_priv *priv) { return 0; }
static inline void i801_del_mux(struct i801_priv *priv) { }

static inline unsigned int i801_get_adapter_class(struct i801_priv *priv)
{
        return I2C_CLASS_HWMON | I2C_CLASS_SPD;
}
#endif

static const struct itco_wdt_platform_data tco_platform_data = {
        .name = "Intel PCH",
        .version = 4,
};

static DEFINE_SPINLOCK(p2sb_spinlock);

static void i801_add_tco(struct i801_priv *priv)
{
        struct pci_dev *pci_dev = priv->pci_dev;
        struct resource tco_res[3], *res;
        struct platform_device *pdev;
        unsigned int devfn;
        u32 tco_base, tco_ctl;
        u32 base_addr, ctrl_val;
        u64 base64_addr;

        if (!(priv->features & FEATURE_TCO))
                return;

        pci_read_config_dword(pci_dev, TCOBASE, &tco_base);
        pci_read_config_dword(pci_dev, TCOCTL, &tco_ctl);
        if (!(tco_ctl & TCOCTL_EN))
                return;

        memset(tco_res, 0, sizeof(tco_res));

        res = &tco_res[ICH_RES_IO_TCO];
        res->start = tco_base & ~1;
        res->end = res->start + 32 - 1;
        res->flags = IORESOURCE_IO;

        /*
         * Power Management registers.
         */
        devfn = PCI_DEVFN(PCI_SLOT(pci_dev->devfn), 2);
        pci_bus_read_config_dword(pci_dev->bus, devfn, ACPIBASE, &base_addr);

        res = &tco_res[ICH_RES_IO_SMI];
        res->start = (base_addr & ~1) + ACPIBASE_SMI_OFF;
        res->end = res->start + 3;
        res->flags = IORESOURCE_IO;

        /*
         * Enable the ACPI I/O space.
         */
        pci_bus_read_config_dword(pci_dev->bus, devfn, ACPICTRL, &ctrl_val);
        ctrl_val |= ACPICTRL_EN;
        pci_bus_write_config_dword(pci_dev->bus, devfn, ACPICTRL, ctrl_val);

        /*
         * We must access the NO_REBOOT bit over the Primary to Sideband
         * bridge (P2SB). The BIOS prevents the P2SB device from being
         * enumerated by the PCI subsystem, so we need to unhide/hide it
         * to lookup the P2SB BAR.
         */
        spin_lock(&p2sb_spinlock);

        devfn = PCI_DEVFN(PCI_SLOT(pci_dev->devfn), 1);

        /* Unhide the P2SB device */
        pci_bus_write_config_byte(pci_dev->bus, devfn, 0xe1, 0x0);

        pci_bus_read_config_dword(pci_dev->bus, devfn, SBREG_BAR, &base_addr);
        base64_addr = base_addr & 0xfffffff0;

        pci_bus_read_config_dword(pci_dev->bus, devfn, SBREG_BAR + 0x4, &base_addr);
        base64_addr |= (u64)base_addr << 32;

        /* Hide the P2SB device */
        pci_bus_write_config_byte(pci_dev->bus, devfn, 0xe1, 0x1);
        spin_unlock(&p2sb_spinlock);

        res = &tco_res[ICH_RES_MEM_OFF];
        res->start = (resource_size_t)base64_addr + SBREG_SMBCTRL;
        res->end = res->start + 3;
        res->flags = IORESOURCE_MEM;

        pdev = platform_device_register_resndata(&pci_dev->dev, "iTCO_wdt", -1,
                                                 tco_res, 3, &tco_platform_data,
                                                 sizeof(tco_platform_data));
        if (IS_ERR(pdev)) {
                dev_warn(&pci_dev->dev, "failed to create iTCO device\n");
                return;
        }

        priv->tco_pdev = pdev;
}

#ifdef CONFIG_ACPI
static acpi_status
i801_acpi_io_handler(u32 function, acpi_physical_address address, u32 bits,
                     u64 *value, void *handler_context, void *region_context)
{
        struct i801_priv *priv = handler_context;
        struct pci_dev *pdev = priv->pci_dev;
        acpi_status status;

        /*
         * Once BIOS AML code touches the OpRegion we warn and inhibit any
         * further access from the driver itself. This device is now owned
         * by the system firmware.
         */
        mutex_lock(&priv->acpi_lock);

        if (!priv->acpi_reserved) {
                priv->acpi_reserved = true;

                dev_warn(&pdev->dev, "BIOS is accessing SMBus registers\n");
                dev_warn(&pdev->dev, "Driver SMBus register access inhibited\n");

                /*
                 * BIOS is accessing the host controller so prevent it from
                 * suspending automatically from now on.
                 */
                pm_runtime_get_sync(&pdev->dev);
        }

        if ((function & ACPI_IO_MASK) == ACPI_READ)
                status = acpi_os_read_port(address, (u32 *)value, bits);
        else
                status = acpi_os_write_port(address, (u32)*value, bits);

        mutex_unlock(&priv->acpi_lock);

        return status;
}

static int i801_acpi_probe(struct i801_priv *priv)
{
        struct acpi_device *adev;
        acpi_status status;

        adev = ACPI_COMPANION(&priv->pci_dev->dev);
        if (adev) {
                status = acpi_install_address_space_handler(adev->handle,
                                ACPI_ADR_SPACE_SYSTEM_IO, i801_acpi_io_handler,
                                NULL, priv);
                if (ACPI_SUCCESS(status))
                        return 0;
        }

        return acpi_check_resource_conflict(&priv->pci_dev->resource[SMBBAR]);
}

static void i801_acpi_remove(struct i801_priv *priv)
{
        struct acpi_device *adev;

        adev = ACPI_COMPANION(&priv->pci_dev->dev);
        if (!adev)
                return;

        acpi_remove_address_space_handler(adev->handle,
                ACPI_ADR_SPACE_SYSTEM_IO, i801_acpi_io_handler);

        mutex_lock(&priv->acpi_lock);
        if (priv->acpi_reserved)
                pm_runtime_put(&priv->pci_dev->dev);
        mutex_unlock(&priv->acpi_lock);
}
#else
static inline int i801_acpi_probe(struct i801_priv *priv) { return 0; }
static inline void i801_acpi_remove(struct i801_priv *priv) { }
#endif

static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
{
        unsigned char temp;
        int err, i;
        struct i801_priv *priv;

        priv = devm_kzalloc(&dev->dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        i2c_set_adapdata(&priv->adapter, priv);
        priv->adapter.owner = THIS_MODULE;
        priv->adapter.class = i801_get_adapter_class(priv);
        priv->adapter.algo = &smbus_algorithm;
        priv->adapter.dev.parent = &dev->dev;
        ACPI_COMPANION_SET(&priv->adapter.dev, ACPI_COMPANION(&dev->dev));
        priv->adapter.retries = 3;
        mutex_init(&priv->acpi_lock);

        priv->pci_dev = dev;
        switch (dev->device) {
        case PCI_DEVICE_ID_INTEL_SUNRISEPOINT_H_SMBUS:
        case PCI_DEVICE_ID_INTEL_SUNRISEPOINT_LP_SMBUS:
        case PCI_DEVICE_ID_INTEL_LEWISBURG_SMBUS:
        case PCI_DEVICE_ID_INTEL_LEWISBURG_SSKU_SMBUS:
        case PCI_DEVICE_ID_INTEL_DNV_SMBUS:
        case PCI_DEVICE_ID_INTEL_KABYLAKE_PCH_H_SMBUS:
                priv->features |= FEATURE_I2C_BLOCK_READ;
                priv->features |= FEATURE_IRQ;
                priv->features |= FEATURE_SMBUS_PEC;
                priv->features |= FEATURE_BLOCK_BUFFER;
                /* If we have ACPI based watchdog use that instead */
                if (!acpi_has_watchdog())
                        priv->features |= FEATURE_TCO;
                priv->features |= FEATURE_HOST_NOTIFY;
                break;

        case PCI_DEVICE_ID_INTEL_PATSBURG_SMBUS_IDF0:
        case PCI_DEVICE_ID_INTEL_PATSBURG_SMBUS_IDF1:
        case PCI_DEVICE_ID_INTEL_PATSBURG_SMBUS_IDF2:
        case PCI_DEVICE_ID_INTEL_WELLSBURG_SMBUS_MS0:
        case PCI_DEVICE_ID_INTEL_WELLSBURG_SMBUS_MS1:
        case PCI_DEVICE_ID_INTEL_WELLSBURG_SMBUS_MS2:
                priv->features |= FEATURE_IDF;
                /* fall through */
        default:
                priv->features |= FEATURE_I2C_BLOCK_READ;
                priv->features |= FEATURE_IRQ;
                /* fall through */
        case PCI_DEVICE_ID_INTEL_82801DB_3:
                priv->features |= FEATURE_SMBUS_PEC;
                priv->features |= FEATURE_BLOCK_BUFFER;
                /* fall through */
        case PCI_DEVICE_ID_INTEL_82801CA_3:
                priv->features |= FEATURE_HOST_NOTIFY;
                /* fall through */
        case PCI_DEVICE_ID_INTEL_82801BA_2:
        case PCI_DEVICE_ID_INTEL_82801AB_3:
        case PCI_DEVICE_ID_INTEL_82801AA_3:
                break;
        }

        /* Disable features on user request */
        for (i = 0; i < ARRAY_SIZE(i801_feature_names); i++) {
                if (priv->features & disable_features & (1 << i))
                        dev_notice(&dev->dev, "%s disabled by user\n",
                                   i801_feature_names[i]);
        }
        priv->features &= ~disable_features;

        err = pcim_enable_device(dev);
        if (err) {
                dev_err(&dev->dev, "Failed to enable SMBus PCI device (%d)\n",
                        err);
                return err;
        }
        pcim_pin_device(dev);

        /* Determine the address of the SMBus area */
        priv->smba = pci_resource_start(dev, SMBBAR);
        if (!priv->smba) {
                dev_err(&dev->dev,
                        "SMBus base address uninitialized, upgrade BIOS\n");
                return -ENODEV;
        }

        if (i801_acpi_probe(priv))
                return -ENODEV;

        err = pcim_iomap_regions(dev, 1 << SMBBAR,
                                 dev_driver_string(&dev->dev));
        if (err) {
                dev_err(&dev->dev,
                        "Failed to request SMBus region 0x%lx-0x%Lx\n",
                        priv->smba,
                        (unsigned long long)pci_resource_end(dev, SMBBAR));
                i801_acpi_remove(priv);
                return err;
        }

        pci_read_config_byte(priv->pci_dev, SMBHSTCFG, &temp);
        priv->original_hstcfg = temp;
        temp &= ~SMBHSTCFG_I2C_EN;      /* SMBus timing */
        if (!(temp & SMBHSTCFG_HST_EN)) {
                dev_info(&dev->dev, "Enabling SMBus device\n");
                temp |= SMBHSTCFG_HST_EN;
        }
        pci_write_config_byte(priv->pci_dev, SMBHSTCFG, temp);

        if (temp & SMBHSTCFG_SMB_SMI_EN) {
                dev_dbg(&dev->dev, "SMBus using interrupt SMI#\n");
                /* Disable SMBus interrupt feature if SMBus using SMI# */
                priv->features &= ~FEATURE_IRQ;
        }
        if (temp & SMBHSTCFG_SPD_WD)
                dev_info(&dev->dev, "SPD Write Disable is set\n");

        /* Clear special mode bits */
        if (priv->features & (FEATURE_SMBUS_PEC | FEATURE_BLOCK_BUFFER))
                outb_p(inb_p(SMBAUXCTL(priv)) &
                       ~(SMBAUXCTL_CRC | SMBAUXCTL_E32B), SMBAUXCTL(priv));

        /* Default timeout in interrupt mode: 200 ms */
        priv->adapter.timeout = HZ / 5;

        if (priv->features & FEATURE_IRQ) {
                u16 pcictl, pcists;

                /* Complain if an interrupt is already pending */
                pci_read_config_word(priv->pci_dev, SMBPCISTS, &pcists);
                if (pcists & SMBPCISTS_INTS)
                        dev_warn(&dev->dev, "An interrupt is pending!\n");

                /* Check if interrupts have been disabled */
                pci_read_config_word(priv->pci_dev, SMBPCICTL, &pcictl);
                if (pcictl & SMBPCICTL_INTDIS) {
                        dev_info(&dev->dev, "Interrupts are disabled\n");
                        priv->features &= ~FEATURE_IRQ;
                }
        }

        if (priv->features & FEATURE_IRQ) {
                init_waitqueue_head(&priv->waitq);

                err = devm_request_irq(&dev->dev, dev->irq, i801_isr,
                                       IRQF_SHARED,
                                       dev_driver_string(&dev->dev), priv);
                if (err) {
                        dev_err(&dev->dev, "Failed to allocate irq %d: %d\n",
                                dev->irq, err);
                        priv->features &= ~FEATURE_IRQ;
                }
        }
        dev_info(&dev->dev, "SMBus using %s\n",
                 priv->features & FEATURE_IRQ ? "PCI interrupt" : "polling");

        i801_add_tco(priv);

        snprintf(priv->adapter.name, sizeof(priv->adapter.name),
                "SMBus I801 adapter at %04lx", priv->smba);
        err = i2c_add_adapter(&priv->adapter);
        if (err) {
                i801_acpi_remove(priv);
                return err;
        }

        i801_enable_host_notify(&priv->adapter);

        i801_probe_optional_slaves(priv);
        /* We ignore errors - multiplexing is optional */
        i801_add_mux(priv);

        pci_set_drvdata(dev, priv);

        pm_runtime_set_autosuspend_delay(&dev->dev, 1000);
        pm_runtime_use_autosuspend(&dev->dev);
        pm_runtime_put_autosuspend(&dev->dev);
        pm_runtime_allow(&dev->dev);

        return 0;
}

static void i801_remove(struct pci_dev *dev)
{
        struct i801_priv *priv = pci_get_drvdata(dev);

        pm_runtime_forbid(&dev->dev);
        pm_runtime_get_noresume(&dev->dev);

        i801_disable_host_notify(priv);
        i801_del_mux(priv);
        i2c_del_adapter(&priv->adapter);
        i801_acpi_remove(priv);
        pci_write_config_byte(dev, SMBHSTCFG, priv->original_hstcfg);

        platform_device_unregister(priv->tco_pdev);

        /*
         * do not call pci_disable_device(dev) since it can cause hard hangs on
         * some systems during power-off (eg. Fujitsu-Siemens Lifebook E8010)
         */
}

#ifdef CONFIG_PM
static int i801_suspend(struct device *dev)
{
        struct pci_dev *pci_dev = to_pci_dev(dev);
        struct i801_priv *priv = pci_get_drvdata(pci_dev);

        pci_write_config_byte(pci_dev, SMBHSTCFG, priv->original_hstcfg);
        return 0;
}

static int i801_resume(struct device *dev)
{
        struct pci_dev *pci_dev = to_pci_dev(dev);
        struct i801_priv *priv = pci_get_drvdata(pci_dev);

        i801_enable_host_notify(&priv->adapter);

        return 0;
}
#endif

static UNIVERSAL_DEV_PM_OPS(i801_pm_ops, i801_suspend,
                            i801_resume, NULL);

static struct pci_driver i801_driver = {
        .name           = "i801_smbus",
        .id_table       = i801_ids,
        .probe          = i801_probe,
        .remove         = i801_remove,
        .driver         = {
                .pm     = &i801_pm_ops,
        },
};

static int __init i2c_i801_init(void)
{
        if (dmi_name_in_vendors("FUJITSU"))
                input_apanel_init();
        return pci_register_driver(&i801_driver);
}

static void __exit i2c_i801_exit(void)
{
        pci_unregister_driver(&i801_driver);
}

MODULE_AUTHOR("Mark D. Studebaker <mdsxyz123@yahoo.com>, Jean Delvare <jdelvare@suse.de>");
MODULE_DESCRIPTION("I801 SMBus driver");
MODULE_LICENSE("GPL");

module_init(i2c_i801_init);
module_exit(i2c_i801_exit);