/*-
* Copyright (c) 2016 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Masanobu SAITOH.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/

/*-
* Copyright (C) 2014 Intel Corporation
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. Neither the name of Intel Corporation nor the names of its
*    contributors may be used to endorse or promote products derived from
*    this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

#include <sys/cdefs.h>
#if 0
__FBSDID("$FreeBSD: head/sys/dev/ismt/ismt.c 266474 2014-05-20 19:55:06Z jimharris $");
#endif
__KERNEL_RCSID(0, "$NetBSD: ismt.c,v 1.11 2023/08/07 06:24:35 msaitoh Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/errno.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/proc.h>

#include <sys/bus.h>

#include <dev/pci/pcidevs.h>
#include <dev/pci/pcireg.h>
#include <dev/pci/pcivar.h>

#include <dev/i2c/i2cvar.h>

#define ISMT_DESC_ENTRIES       32

/* Hardware Descriptor Constants - Control Field */
#define ISMT_DESC_CWRL  0x01    /* Command/Write Length */
#define ISMT_DESC_BLK   0X04    /* Perform Block Transaction */
#define ISMT_DESC_FAIR  0x08    /* Set fairness flag upon successful arbit. */
#define ISMT_DESC_PEC   0x10    /* Packet Error Code */
#define ISMT_DESC_I2C   0x20    /* I2C Enable */
#define ISMT_DESC_INT   0x40    /* Interrupt */
#define ISMT_DESC_SOE   0x80    /* Stop On Error */

/* Hardware Descriptor Constants - Status Field */
#define ISMT_DESC_SCS   0x01    /* Success */
#define ISMT_DESC_DLTO  0x04    /* Data Low Time Out */
#define ISMT_DESC_NAK   0x08    /* NAK Received */
#define ISMT_DESC_CRC   0x10    /* CRC Error */
#define ISMT_DESC_CLTO  0x20    /* Clock Low Time Out */
#define ISMT_DESC_COL   0x40    /* Collisions */
#define ISMT_DESC_LPR   0x80    /* Large Packet Received */

/* Macros */
#define ISMT_DESC_ADDR_RW(addr, is_read) (((addr) << 1) | (is_read))

/* iSMT General Register address offsets (SMBBAR + <addr>) */
#define ISMT_GR_GCTRL           0x000   /* General Control */
#define ISMT_GR_SMTICL          0x008   /* SMT Interrupt Cause Location */
#define ISMT_GR_ERRINTMSK       0x010   /* Error Interrupt Mask */
#define ISMT_GR_ERRAERMSK       0x014   /* Error AER Mask */
#define ISMT_GR_ERRSTS          0x018   /* Error Status */
#define ISMT_GR_ERRINFO         0x01c   /* Error Information */

/* iSMT Master Registers */
#define ISMT_MSTR_MDBA          0x100   /* Master Descriptor Base Address */
#define ISMT_MSTR_MCTRL         0x108   /* Master Control */
#define ISMT_MSTR_MSTS          0x10c   /* Master Status */
#define ISMT_MSTR_MDS           0x110   /* Master Descriptor Size */
#define ISMT_MSTR_RPOLICY       0x114   /* Retry Policy */

/* iSMT Miscellaneous Registers */
#define ISMT_SPGT       0x300   /* SMBus PHY Global Timing */

/* General Control Register (GCTRL) bit definitions */
#define ISMT_GCTRL_TRST 0x04    /* Target Reset */
#define ISMT_GCTRL_KILL 0x08    /* Kill */
#define ISMT_GCTRL_SRST 0x40    /* Soft Reset */

/* Master Control Register (MCTRL) bit definitions */
#define ISMT_MCTRL_SS   0x01            /* Start/Stop */
#define ISMT_MCTRL_MEIE 0x10            /* Master Error Interrupt Enable */
#define ISMT_MCTRL_FMHP 0x00ff0000      /* Firmware Master Head Ptr (FMHP) */

/* Master Status Register (MSTS) bit definitions */
#define ISMT_MSTS_HMTP  0xff0000        /* HW Master Tail Pointer (HMTP) */
#define ISMT_MSTS_MIS   0x20            /* Master Interrupt Status (MIS) */
#define ISMT_MSTS_MEIS  0x10            /* Master Error Int Status (MEIS) */
#define ISMT_MSTS_IP    0x01            /* In Progress */

/* Master Descriptor Size (MDS) bit definitions */
#define ISMT_MDS_MASK   0xff    /* Master Descriptor Size mask (MDS) */

/* SMBus PHY Global Timing Register (SPGT) bit definitions */
#define ISMT_SPGT_SPD_MASK      0xc0000000      /* SMBus Speed mask */
#define ISMT_SPGT_SPD_80K       0x00            /* 80 kHz */
#define ISMT_SPGT_SPD_100K      (0x1 << 30)     /* 100 kHz */
#define ISMT_SPGT_SPD_400K      (0x2 << 30)     /* 400 kHz */
#define ISMT_SPGT_SPD_1M        (0x3 << 30)     /* 1 MHz */

/* MSI Control Register (MSICTL) bit definitions */
#define ISMT_MSICTL_MSIE        0x01    /* MSI Enable */

#define ISMT_MAX_BLOCK_SIZE     32 /* per SMBus spec */

#define ISMT_INTR_TIMEOUT       (hz / 50) /* 0.02s */
#define ISMT_POLL_DELAY         100     /* 100usec */
#define ISMT_POLL_COUNT         200     /* 100usec * 200 = 0.02s */

//#define ISMT_DEBUG    aprint_debug_dev
#ifndef ISMT_DEBUG
#define ISMT_DEBUG(...)
#endif

#define ISMT_LOW(a)     ((a) & 0xFFFFFFFFULL)
#define ISMT_HIGH(a)    (((uint64_t)(a) >> 32) & 0xFFFFFFFFFULL)

/* iSMT Hardware Descriptor */
struct ismt_desc {
       uint8_t tgtaddr_rw;     /* target address & r/w bit */
       uint8_t wr_len_cmd;     /* write length in bytes or a command */
       uint8_t rd_len;         /* read length */
       uint8_t control;        /* control bits */
       uint8_t status;         /* status bits */
       uint8_t retry;          /* collision retry and retry count */
       uint8_t rxbytes;        /* received bytes */
       uint8_t txbytes;        /* transmitted bytes */
       uint32_t dptr_low;      /* lower 32 bit of the data pointer */
       uint32_t dptr_high;     /* upper 32 bit of the data pointer */
} __packed;

#define DESC_SIZE       (ISMT_DESC_ENTRIES * sizeof(struct ismt_desc))

#define DMA_BUFFER_SIZE 64

struct ismt_softc {
       device_t                pcidev;
       device_t                smbdev;

       struct i2c_controller   sc_i2c_tag;

       pci_chipset_tag_t       sc_pc;
       pcitag_t                sc_pcitag;
       pci_intr_handle_t       *sc_pihp;
       void                    *sc_ih;

       bus_space_tag_t         mmio_tag;
       bus_space_handle_t      mmio_handle;
       bus_size_t              mmio_size;

       uint8_t                 head;

       struct ismt_desc        *desc;
       bus_dma_tag_t           desc_dma_tag;
       bus_dmamap_t            desc_dma_map;
       bus_dma_segment_t       desc_dma_seg;
       int                     desc_rseg;

       uint8_t                 *dma_buffer;
       bus_dma_tag_t           dma_buffer_dma_tag;
       bus_dmamap_t            dma_buffer_dma_map;
       bus_dma_segment_t       dma_buffer_dma_seg;
       int                     dma_buffer_rseg;

       uint8_t                 using_msi;
};

static int      ismt_intr(void *);
static int      ismt_i2c_exec(void *, i2c_op_t, i2c_addr_t, const void *,
   size_t, void *, size_t, int);
static struct ismt_desc *ismt_alloc_desc(struct ismt_softc *);
static int      ismt_submit(struct ismt_softc *, struct ismt_desc *,
   i2c_addr_t, uint8_t, int);
static int      ismt_quick(struct ismt_softc *, i2c_addr_t, i2c_op_t, int);
static int      ismt_sendb(struct ismt_softc *, i2c_addr_t, i2c_op_t, char,
   int);
static int      ismt_recvb(struct ismt_softc *, i2c_addr_t, i2c_op_t, int);
static int      ismt_writeb(struct ismt_softc *, i2c_addr_t, i2c_op_t, uint8_t,
   char, int);
static int      ismt_writew(struct ismt_softc *, i2c_addr_t, i2c_op_t, uint8_t,
   uint16_t, int);
static int      ismt_readb(struct ismt_softc *, i2c_addr_t, i2c_op_t, char,
   int);
static int      ismt_readw(struct ismt_softc *, i2c_addr_t, i2c_op_t, char,
   int);

static int      ismt_match(device_t, cfdata_t, void *);
static void     ismt_attach(device_t, device_t, void *);
static int      ismt_detach(device_t, int);
static int      ismt_rescan(device_t, const char *, const int *);
static void     ismt_config_interrupts(device_t);
static void     ismt_chdet(device_t, device_t);

CFATTACH_DECL3_NEW(ismt, sizeof(struct ismt_softc),
   ismt_match, ismt_attach, ismt_detach, NULL, ismt_rescan, ismt_chdet,
   DVF_DETACH_SHUTDOWN);

static int
ismt_intr(void *arg)
{
       struct ismt_softc *sc = arg;
       uint32_t val;

       val = bus_space_read_4(sc->mmio_tag, sc->mmio_handle, ISMT_MSTR_MSTS);
       if ((sc->using_msi == 0)
           && (val & (ISMT_MSTS_MIS | ISMT_MSTS_MEIS)) == 0)
               return 0; /* Not for me */

       ISMT_DEBUG(sc->pcidev, "%s MSTS = 0x%08x\n", __func__, val);

       val |= (ISMT_MSTS_MIS | ISMT_MSTS_MEIS);
       bus_space_write_4(sc->mmio_tag, sc->mmio_handle, ISMT_MSTR_MSTS, val);

       if (sc->using_msi)
               wakeup(sc);

       return 1;
}

static int
ismt_i2c_exec(void *cookie, i2c_op_t op, i2c_addr_t addr,
   const void *cmd, size_t cmdlen, void *buf, size_t buflen, int flags)
{
       struct ismt_softc *sc = cookie;
       uint8_t *p = buf;
       int rv;

       ISMT_DEBUG(sc->pcidev, "exec: op %d, addr 0x%02x, cmdlen %zu, "
           " buflen %zu, flags 0x%02x\n", op, addr, cmdlen, buflen, flags);

       if ((cmdlen == 0) && (buflen == 0))
               return ismt_quick(sc, addr, op, flags);

       if (I2C_OP_READ_P(op) && (cmdlen == 0) && (buflen == 1)) {
               rv = ismt_recvb(sc, addr, op, flags);
               if (rv == -1)
                       return -1;
               *p = (uint8_t)rv;
               return 0;
       }

       if ((I2C_OP_READ_P(op)) && (cmdlen == 1) && (buflen == 1)) {
               rv = ismt_readb(sc, addr, op, *(const uint8_t*)cmd, flags);
               if (rv == -1)
                       return -1;
               *p = (uint8_t)rv;
               return 0;
       }

       if ((I2C_OP_READ_P(op)) && (cmdlen == 1) && (buflen == 2)) {
               rv = ismt_readw(sc, addr, op, *(const uint8_t*)cmd, flags);
               if (rv == -1)
                       return -1;
               *(uint16_t *)p = (uint16_t)rv;
               return 0;
       }

       if ((I2C_OP_WRITE_P(op)) && (cmdlen == 0) && (buflen == 1))
               return ismt_sendb(sc, addr, op, *(uint8_t*)buf, flags);

       if ((I2C_OP_WRITE_P(op)) && (cmdlen == 1) && (buflen == 1))
               return ismt_writeb(sc, addr, op, *(const uint8_t*)cmd,
                   *(uint8_t*)buf, flags);

       if ((I2C_OP_WRITE_P(op)) && (cmdlen == 1) && (buflen == 2))
               return ismt_writew(sc, addr, op,
                   *(const uint8_t*)cmd, *((uint16_t *)buf), flags);

       return -1;
}

static struct ismt_desc *
ismt_alloc_desc(struct ismt_softc *sc)
{
       struct ismt_desc *desc;

       desc = &sc->desc[sc->head++];
       if (sc->head == ISMT_DESC_ENTRIES)
               sc->head = 0;

       memset(desc, 0, sizeof(*desc));

       return (desc);
}

static int
ismt_submit(struct ismt_softc *sc, struct ismt_desc *desc, i2c_addr_t slave,
   uint8_t is_read, int flags)
{
       uint32_t err, fmhp, val;
       int timeout, i;

       if (sc->using_msi == 0)
               flags |= I2C_F_POLL;
       desc->control |= ISMT_DESC_FAIR;
       if ((flags & I2C_F_POLL) == 0)
               desc->control |= ISMT_DESC_INT;

       desc->tgtaddr_rw = ISMT_DESC_ADDR_RW(slave, is_read);
       desc->dptr_low = ISMT_LOW(sc->dma_buffer_dma_map->dm_segs[0].ds_addr);
       desc->dptr_high = ISMT_HIGH(sc->dma_buffer_dma_map->dm_segs[0].ds_addr);

       bus_dmamap_sync(sc->desc_dma_tag, sc->desc_dma_map,
           desc - &sc->desc[0], sizeof(struct ismt_desc),
           BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);

       fmhp = sc->head << 16;
       val = bus_space_read_4(sc->mmio_tag, sc->mmio_handle, ISMT_MSTR_MCTRL);
       val &= ~ISMT_MCTRL_FMHP;
       val |= fmhp;
       bus_space_write_4(sc->mmio_tag, sc->mmio_handle, ISMT_MSTR_MCTRL, val);

       /* set the start bit */
       val = bus_space_read_4(sc->mmio_tag, sc->mmio_handle, ISMT_MSTR_MCTRL);
       val |= ISMT_MCTRL_SS;
       bus_space_write_4(sc->mmio_tag, sc->mmio_handle, ISMT_MSTR_MCTRL, val);

       i = 0;
       if ((flags & I2C_F_POLL) == 0) {
               timeout = ISMT_INTR_TIMEOUT;
               if (timeout == 0)
                       timeout = 1;
               err = tsleep(sc, PWAIT, "ismt_wait", timeout);
               if (err != 0) {
                       ISMT_DEBUG(sc->pcidev, "%s timeout\n", __func__);
                       return -1;
               }
       } else {
               /* Polling */
               for (i = 0; i < ISMT_POLL_COUNT; i++) {
                       val = bus_space_read_4(sc->mmio_tag, sc->mmio_handle,
                           ISMT_MSTR_MSTS);
                       if ((val & (ISMT_MSTS_MIS | ISMT_MSTS_MEIS)) != 0) {
                               ismt_intr(sc);
                               err = 0;
                               break;
                       }
                       delay(ISMT_POLL_DELAY);
               }
               if (i >= ISMT_POLL_COUNT) {
                       ISMT_DEBUG(sc->pcidev, "%s polling timeout. "
                           "MSTS = %08x\n", __func__, val);
                       return -1;
               }
       }

       bus_dmamap_sync(sc->desc_dma_tag, sc->desc_dma_map,
           desc - &sc->desc[0], sizeof(struct ismt_desc),
               BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE);
       ISMT_DEBUG(sc->pcidev, "%s status=0x%02x\n", __func__, desc->status);

       if (desc->status & ISMT_DESC_SCS)
               return 0;

       if (desc->status & ISMT_DESC_NAK)
               return -1;

       if (desc->status & ISMT_DESC_CRC)
               return -1;

       if (desc->status & ISMT_DESC_COL)
               return -1;

       if (desc->status & ISMT_DESC_LPR)
               return -1;

       if (desc->status & (ISMT_DESC_DLTO | ISMT_DESC_CLTO))
               return -1;

       return -1;
}

static int
ismt_quick(struct ismt_softc *sc, i2c_addr_t slave, i2c_op_t op, int flags)
{
       struct ismt_desc        *desc;
       int                     is_read;

       ISMT_DEBUG(sc->pcidev, "%s\n", __func__);

       desc = ismt_alloc_desc(sc);
       is_read = I2C_OP_READ_P(op);
       return (ismt_submit(sc, desc, slave, is_read, flags));
}

static int
ismt_sendb(struct ismt_softc *sc, i2c_addr_t slave, i2c_op_t op, char byte,
   int flags)
{
       struct ismt_desc        *desc;

       ISMT_DEBUG(sc->pcidev, "%s\n", __func__);

       desc = ismt_alloc_desc(sc);
       desc->control = ISMT_DESC_CWRL;
       desc->wr_len_cmd = byte;

       return (ismt_submit(sc, desc, slave, 0, flags));
}

static int
ismt_recvb(struct ismt_softc *sc, i2c_addr_t slave, i2c_op_t op, int flags)
{
       struct ismt_desc        *desc;
       int                     err;

       ISMT_DEBUG(sc->pcidev, "%s\n", __func__);

       desc = ismt_alloc_desc(sc);
       desc->rd_len = 1;

       err = ismt_submit(sc, desc, slave, 1, flags);

       if (err != 0)
               return (err);

       return sc->dma_buffer[0];
}

static int
ismt_writeb(struct ismt_softc *sc, i2c_addr_t slave, i2c_op_t op, uint8_t cmd,
   char byte, int flags)
{
       struct ismt_desc        *desc;

       ISMT_DEBUG(sc->pcidev, "%s\n", __func__);

       desc = ismt_alloc_desc(sc);
       desc->wr_len_cmd = 2;
       sc->dma_buffer[0] = cmd;
       sc->dma_buffer[1] = byte;

       return (ismt_submit(sc, desc, slave, 0, flags));
}

static int
ismt_writew(struct ismt_softc *sc, i2c_addr_t slave, i2c_op_t op, uint8_t cmd,
   uint16_t word, int flags)
{
       struct ismt_desc        *desc;

       ISMT_DEBUG(sc->pcidev, "%s\n", __func__);

       desc = ismt_alloc_desc(sc);
       desc->wr_len_cmd = 3;
       sc->dma_buffer[0] = cmd;
       sc->dma_buffer[1] = word & 0xFF;
       sc->dma_buffer[2] = word >> 8;

       return (ismt_submit(sc, desc, slave, 0, flags));
}

static int
ismt_readb(struct ismt_softc *sc, i2c_addr_t slave, i2c_op_t op, char cmd,
   int flags)
{
       struct ismt_desc        *desc;
       int                     err;

       ISMT_DEBUG(sc->pcidev, "%s\n", __func__);

       desc = ismt_alloc_desc(sc);
       desc->control = ISMT_DESC_CWRL;
       desc->wr_len_cmd = cmd;
       desc->rd_len = 1;

       err = ismt_submit(sc, desc, slave, 1, flags);

       if (err != 0)
               return (err);

       return sc->dma_buffer[0];
}

static int
ismt_readw(struct ismt_softc *sc, i2c_addr_t slave, i2c_op_t op, char cmd,
   int flags)
{
       struct ismt_desc        *desc;
       uint16_t                word;
       int                     err;

       ISMT_DEBUG(sc->pcidev, "%s\n", __func__);

       desc = ismt_alloc_desc(sc);
       desc->control = ISMT_DESC_CWRL;
       desc->wr_len_cmd = cmd;
       desc->rd_len = 2;

       err = ismt_submit(sc, desc, slave, 1, flags);

       if (err != 0)
               return (err);

       word = sc->dma_buffer[0] | (sc->dma_buffer[1] << 8);

       return word;
}

#if 0
static int
ismt_pcall(struct ismt_softc *sc, i2c_addr_t slave, i2c_op_t op, char cmd,
   uint16_t sdata, uint16_t *rdata, int flags)
{
       struct ismt_desc        *desc;
       int                     err;

       ISMT_DEBUG(sc->pcidev, "%s\n", __func__);

       desc = ismt_alloc_desc(sc);
       desc->wr_len_cmd = 3;
       desc->rd_len = 2;
       sc->dma_buffer[0] = cmd;
       sc->dma_buffer[1] = sdata & 0xff;
       sc->dma_buffer[2] = sdata >> 8;

       err = ismt_submit(sc, desc, slave, 0, flags);

       if (err != 0)
               return (err);

       *rdata = sc->dma_buffer[0] | (sc->dma_buffer[1] << 8);

       return (err);
}

static int
ismt_bwrite(struct ismt_softc *sc, i2c_addr_t slave, i2c_op_t op, char cmd,
   u_char count, char *buf, int flags)
{
       struct ismt_desc        *desc;

       ISMT_DEBUG(sc->pcidev, "%s\n", __func__);

       if (count == 0 || count > ISMT_MAX_BLOCK_SIZE)
               return -1;

       desc = ismt_alloc_desc(sc);
       desc->control = ISMT_DESC_I2C;
       desc->wr_len_cmd = count + 1;
       sc->dma_buffer[0] = cmd;
       memcpy(&sc->dma_buffer[1], buf, count);

       return (ismt_submit(sc, desc, slave, 0, flags));
}

static int
ismt_bread(struct ismt_softc *sc, i2c_addr_t slave, i2c_op_t op, char cmd,
   u_char *count, char *buf, int flags)
{
       struct ismt_desc        *desc;
       int                     err;

       ISMT_DEBUG(sc->pcidev, "%s\n", __func__);

       if (*count == 0 || *count > ISMT_MAX_BLOCK_SIZE)
               return -1;

       desc = ismt_alloc_desc(sc);
       desc->control = ISMT_DESC_I2C | ISMT_DESC_CWRL;
       desc->wr_len_cmd = cmd;
       desc->rd_len = *count;

       err = ismt_submit(sc, desc, slave, 0, flags);

       if (err != 0)
               return (err);

       memcpy(buf, sc->dma_buffer, desc->rxbytes);
       *count = desc->rxbytes;

       return (err);
}
#endif

static int
ismt_detach(device_t self, int flags)
{
       struct ismt_softc *sc = device_private(self);
       int error;

       ISMT_DEBUG(self, "%s\n", __func__);
       error = config_detach_children(self, flags);
       if (error)
               return error;

       if (sc->sc_ih != NULL) {
               pci_intr_disestablish(sc->sc_pc, sc->sc_ih);
               sc->sc_ih = NULL;
       }
       if (sc->sc_pihp != NULL) {
               pci_intr_release(sc->sc_pc, sc->sc_pihp, 1);
               sc->sc_pihp = NULL;
       }

       bus_dmamap_unload(sc->desc_dma_tag, sc->desc_dma_map);
       bus_dmamap_unload(sc->dma_buffer_dma_tag, sc->dma_buffer_dma_map);

       bus_dmamem_free(sc->desc_dma_tag, &sc->desc_dma_seg, sc->desc_rseg);
       bus_dmamem_free(sc->dma_buffer_dma_tag, &sc->dma_buffer_dma_seg,
           sc->dma_buffer_rseg);

       if (sc->mmio_size)
               bus_space_unmap(sc->mmio_tag, sc->mmio_handle, sc->mmio_size);

       iic_tag_fini(&sc->sc_i2c_tag);
       return 0;
}

static void
ismt_attach(device_t parent, device_t self, void *aux)
{
       struct ismt_softc *sc = device_private(self);
       struct pci_attach_args *pa = aux;
       const char *intrstr = NULL;
       char intrbuf[PCI_INTRSTR_LEN];
       pcireg_t reg;
       int val;

       sc->pcidev = self;
       sc->sc_pc = pa->pa_pc;
       sc->sc_pcitag = pa->pa_tag;

       /* Enable busmastering */
       reg = pci_conf_read(sc->sc_pc, sc->sc_pcitag, PCI_COMMAND_STATUS_REG);
       reg |= PCI_COMMAND_MASTER_ENABLE;
       pci_conf_write(sc->sc_pc, sc->sc_pcitag, PCI_COMMAND_STATUS_REG, reg);

       pci_aprint_devinfo(pa, NULL);

       /* Map mem space */
       if (pci_mapreg_map(pa, PCI_BAR0, PCI_MAPREG_TYPE_MEM, 0,
           &sc->mmio_tag, &sc->mmio_handle, NULL, &sc->mmio_size)) {
               aprint_error_dev(self, "can't map mem space\n");
               goto fail;
       }

       if (pci_dma64_available(pa)) {
               sc->desc_dma_tag = pa->pa_dmat64;
               sc->dma_buffer_dma_tag = pa->pa_dmat64;
       } else {
               sc->desc_dma_tag = pa->pa_dmat;
               sc->dma_buffer_dma_tag = pa->pa_dmat;
       }
       bus_dmamem_alloc(sc->desc_dma_tag, DESC_SIZE, PAGE_SIZE, 0,
           &sc->desc_dma_seg, ISMT_DESC_ENTRIES, &sc->desc_rseg,
           BUS_DMA_WAITOK);
       bus_dmamem_alloc(sc->dma_buffer_dma_tag, DMA_BUFFER_SIZE, PAGE_SIZE, 0,
           &sc->dma_buffer_dma_seg, 1, &sc->dma_buffer_rseg, BUS_DMA_WAITOK);

       bus_dmamem_map(sc->desc_dma_tag, &sc->desc_dma_seg,
           sc->desc_rseg, DESC_SIZE, (void **)&sc->desc, BUS_DMA_COHERENT);
       bus_dmamem_map(sc->dma_buffer_dma_tag, &sc->dma_buffer_dma_seg,
           sc->dma_buffer_rseg, DMA_BUFFER_SIZE, (void **)&sc->dma_buffer,
           BUS_DMA_COHERENT);

       bus_dmamap_create(sc->desc_dma_tag, DESC_SIZE, 1,
           DESC_SIZE, 0, 0, &sc->desc_dma_map);
       bus_dmamap_create(sc->dma_buffer_dma_tag, DMA_BUFFER_SIZE, 1,
           DMA_BUFFER_SIZE, 0, 0, &sc->dma_buffer_dma_map);

       bus_dmamap_load(sc->desc_dma_tag,
           sc->desc_dma_map, sc->desc, DESC_SIZE, NULL, 0);
       bus_dmamap_load(sc->dma_buffer_dma_tag,
           sc->dma_buffer_dma_map, sc->dma_buffer, DMA_BUFFER_SIZE,
           NULL, 0);

       bus_space_write_4(sc->mmio_tag, sc->mmio_handle, ISMT_MSTR_MDBA,
           ISMT_LOW(sc->desc_dma_map->dm_segs[0].ds_addr));
       bus_space_write_4(sc->mmio_tag, sc->mmio_handle, ISMT_MSTR_MDBA + 4,
           ISMT_HIGH(sc->desc_dma_map->dm_segs[0].ds_addr));

       /* initialize the Master Control Register (MCTRL) */
       bus_space_write_4(sc->mmio_tag, sc->mmio_handle, ISMT_MSTR_MCTRL,
           ISMT_MCTRL_MEIE);

       /* initialize the Master Status Register (MSTS) */
       bus_space_write_4(sc->mmio_tag, sc->mmio_handle, ISMT_MSTR_MSTS, 0);

       /* initialize the Master Descriptor Size (MDS) */
       val = bus_space_read_4(sc->mmio_tag, sc->mmio_handle, ISMT_MSTR_MDS);
       val &= ~ISMT_MDS_MASK;
       val |= (ISMT_DESC_ENTRIES - 1);
       bus_space_write_4(sc->mmio_tag, sc->mmio_handle, ISMT_MSTR_MDS, val);

       if (pci_intr_alloc(pa, &sc->sc_pihp, NULL, 0)) {
               aprint_error_dev(self, "couldn't map interrupt\n");
               return;
       }
       intrstr = pci_intr_string(pa->pa_pc, sc->sc_pihp[0], intrbuf,
           sizeof(intrbuf));
       sc->sc_ih = pci_intr_establish_xname(pa->pa_pc, sc->sc_pihp[0],
           IPL_BIO, ismt_intr, sc, device_xname(self));
       if (sc->sc_ih == NULL) {
               aprint_error_dev(sc->pcidev, "unable to establish %s\n",
                   (pci_intr_type(pa->pa_pc, sc->sc_pihp[0])
                       == PCI_INTR_TYPE_MSI) ? "MSI" : "INTx");
               /* Polling */
       }

       if (pci_intr_type(pa->pa_pc, sc->sc_pihp[0]) == PCI_INTR_TYPE_MSI)
               sc->using_msi = 1;

       aprint_normal_dev(sc->pcidev, "interrupting at %s\n", intrstr);

       sc->smbdev = NULL;
       if (!pmf_device_register(self, NULL, NULL))
               aprint_error_dev(self, "couldn't establish power handler\n");

       config_interrupts(self, ismt_config_interrupts);
       return;

fail:
       ismt_detach(sc->pcidev, 0);

       return;
}

static int
ismt_match(device_t parent, cfdata_t match, void *aux)
{
       struct pci_attach_args *pa = aux;

       if (PCI_VENDOR(pa->pa_id) != PCI_VENDOR_INTEL)
               return 0;

       switch (PCI_PRODUCT(pa->pa_id)) {
       case PCI_PRODUCT_INTEL_S1200_SMBUS_0:
       case PCI_PRODUCT_INTEL_S1200_SMBUS_1:
       case PCI_PRODUCT_INTEL_C2000_SMBUS:
       case PCI_PRODUCT_INTEL_C3K_SMBUS:
       case PCI_PRODUCT_INTEL_SNR_SMB_HOST:
               break;
       default:
               return 0;
       }

       return 1;
}

static int
ismt_rescan(device_t self, const char *ifattr, const int *locators)
{
       struct ismt_softc *sc = device_private(self);
       struct i2cbus_attach_args iba;

       if (sc->smbdev != NULL)
               return 0;

       /* Attach I2C bus */
       iic_tag_init(&sc->sc_i2c_tag);
       sc->sc_i2c_tag.ic_cookie = sc;
       sc->sc_i2c_tag.ic_exec = ismt_i2c_exec;

       memset(&iba, 0, sizeof(iba));
       iba.iba_tag = &sc->sc_i2c_tag;
       sc->smbdev = config_found(self, &iba, iicbus_print, CFARGS_NONE);

       return 0;
}

static void
ismt_config_interrupts(device_t self)
{

       ismt_rescan(self, NULL, NULL);
}

static void
ismt_chdet(device_t self, device_t child)
{
       struct ismt_softc *sc = device_private(self);

       if (sc->smbdev == child)
               sc->smbdev = NULL;

}

MODULE(MODULE_CLASS_DRIVER, ismt, "pci");

#ifdef _MODULE
#include "ioconf.c"
#endif

static int
ismt_modcmd(modcmd_t cmd, void *opaque)
{
       int error = 0;

       switch (cmd) {
       case MODULE_CMD_INIT:
#ifdef _MODULE
               error = config_init_component(cfdriver_ioconf_ismt,
                   cfattach_ioconf_ismt, cfdata_ioconf_ismt);
#endif
               return error;
       case MODULE_CMD_FINI:
#ifdef _MODULE
               error = config_fini_component(cfdriver_ioconf_ismt,
                   cfattach_ioconf_ismt, cfdata_ioconf_ismt);
#endif
               return error;
       default:
               return ENOTTY;
       }
}