/*
 * Access to HP-HIL MLC through HP System Device Controller.
 *
 * Copyright (c) 2001 Brian S. Julin
 * 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,
 *    without modification.
 * 2. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL").
 *
 * 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
 *
 * References:
 * HP-HIL Technical Reference Manual.  Hewlett Packard Product No. 45918A
 * System Device Controller Microprocessor Firmware Theory of Operation
 *      for Part Number 1820-4784 Revision B.  Dwg No. A-1820-4784-2
 *
 */

#include <linux/hil_mlc.h>
#include <linux/hp_sdc.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/semaphore.h>

#define PREFIX "HP SDC MLC: "

static hil_mlc hp_sdc_mlc;

MODULE_AUTHOR("Brian S. Julin <bri@calyx.com>");
MODULE_DESCRIPTION("Glue for onboard HIL MLC in HP-PARISC machines");
MODULE_LICENSE("Dual BSD/GPL");

static struct hp_sdc_mlc_priv_s {
        int emtestmode;
        hp_sdc_transaction trans;
        u8 tseq[16];
        int got5x;
} hp_sdc_mlc_priv;

/************************* Interrupt context ******************************/
static void hp_sdc_mlc_isr (int irq, void *dev_id,
                            uint8_t status, uint8_t data)
{
        int idx;
        hil_mlc *mlc = &hp_sdc_mlc;

        write_lock(&mlc->lock);
        if (mlc->icount < 0) {
                printk(KERN_WARNING PREFIX "HIL Overflow!\n");
                up(&mlc->isem);
                goto out;
        }
        idx = 15 - mlc->icount;
        if ((status & HP_SDC_STATUS_IRQMASK) == HP_SDC_STATUS_HILDATA) {
                mlc->ipacket[idx] |= data | HIL_ERR_INT;
                mlc->icount--;
                if (hp_sdc_mlc_priv.got5x || !idx)
                        goto check;
                if ((mlc->ipacket[idx - 1] & HIL_PKT_ADDR_MASK) !=
                    (mlc->ipacket[idx] & HIL_PKT_ADDR_MASK)) {
                        mlc->ipacket[idx] &= ~HIL_PKT_ADDR_MASK;
                        mlc->ipacket[idx] |= (mlc->ipacket[idx - 1]
                                                & HIL_PKT_ADDR_MASK);
                }
                goto check;
        }
        /* We know status is 5X */
        if (data & HP_SDC_HIL_ISERR)
                goto err;
        mlc->ipacket[idx] =
                (data & HP_SDC_HIL_R1MASK) << HIL_PKT_ADDR_SHIFT;
        hp_sdc_mlc_priv.got5x = 1;
        goto out;

 check:
        hp_sdc_mlc_priv.got5x = 0;
        if (mlc->imatch == 0)
                goto done;
        if ((mlc->imatch == (HIL_ERR_INT | HIL_PKT_CMD | HIL_CMD_POL))
            && (mlc->ipacket[idx] == (mlc->imatch | idx)))
                goto done;
        if (mlc->ipacket[idx] == mlc->imatch)
                goto done;
        goto out;

 err:
        printk(KERN_DEBUG PREFIX "err code %x\n", data);

        switch (data) {
        case HP_SDC_HIL_RC_DONE:
                printk(KERN_WARNING PREFIX "Bastard SDC reconfigured loop!\n");
                break;

        case HP_SDC_HIL_ERR:
                mlc->ipacket[idx] |= HIL_ERR_INT | HIL_ERR_PERR |
                                        HIL_ERR_FERR | HIL_ERR_FOF;
                break;

        case HP_SDC_HIL_TO:
                mlc->ipacket[idx] |= HIL_ERR_INT | HIL_ERR_LERR;
                break;

        case HP_SDC_HIL_RC:
                printk(KERN_WARNING PREFIX "Bastard SDC decided to reconfigure loop!\n");
                break;

        default:
                printk(KERN_WARNING PREFIX "Unknown HIL Error status (%x)!\n", data);
                break;
        }

        /* No more data will be coming due to an error. */
 done:
        tasklet_schedule(mlc->tasklet);
        up(&mlc->isem);
 out:
        write_unlock(&mlc->lock);
}


/******************** Tasklet or userspace context functions ****************/

static int hp_sdc_mlc_in(hil_mlc *mlc, suseconds_t timeout)
{
        struct hp_sdc_mlc_priv_s *priv;
        int rc = 2;

        priv = mlc->priv;

        /* Try to down the semaphore */
        if (down_trylock(&mlc->isem)) {
                if (priv->emtestmode) {
                        mlc->ipacket[0] =
                                HIL_ERR_INT | (mlc->opacket &
                                               (HIL_PKT_CMD |
                                                HIL_PKT_ADDR_MASK |
                                                HIL_PKT_DATA_MASK));
                        mlc->icount = 14;
                        /* printk(KERN_DEBUG PREFIX ">[%x]\n", mlc->ipacket[0]); */
                        goto wasup;
                }
                if (time_after(jiffies, mlc->instart + mlc->intimeout)) {
                        /*      printk("!%i %i",
                                tv.tv_usec - mlc->instart.tv_usec,
                                mlc->intimeout);
                         */
                        rc = 1;
                        up(&mlc->isem);
                }
                goto done;
        }
 wasup:
        up(&mlc->isem);
        rc = 0;
 done:
        return rc;
}

static int hp_sdc_mlc_cts(hil_mlc *mlc)
{
        struct hp_sdc_mlc_priv_s *priv;

        priv = mlc->priv;

        /* Try to down the semaphores -- they should be up. */
        BUG_ON(down_trylock(&mlc->isem));
        BUG_ON(down_trylock(&mlc->osem));

        up(&mlc->isem);
        up(&mlc->osem);

        if (down_trylock(&mlc->csem)) {
                if (priv->trans.act.semaphore != &mlc->csem)
                        goto poll;
                else
                        goto busy;
        }

        if (!(priv->tseq[4] & HP_SDC_USE_LOOP))
                goto done;

 poll:
        priv->trans.act.semaphore = &mlc->csem;
        priv->trans.actidx = 0;
        priv->trans.idx = 1;
        priv->trans.endidx = 5;
        priv->tseq[0] =
                HP_SDC_ACT_POSTCMD | HP_SDC_ACT_DATAIN | HP_SDC_ACT_SEMAPHORE;
        priv->tseq[1] = HP_SDC_CMD_READ_USE;
        priv->tseq[2] = 1;
        priv->tseq[3] = 0;
        priv->tseq[4] = 0;
        return __hp_sdc_enqueue_transaction(&priv->trans);
 busy:
        return 1;
 done:
        priv->trans.act.semaphore = &mlc->osem;
        up(&mlc->csem);
        return 0;
}

static int hp_sdc_mlc_out(hil_mlc *mlc)
{
        struct hp_sdc_mlc_priv_s *priv;

        priv = mlc->priv;

        /* Try to down the semaphore -- it should be up. */
        BUG_ON(down_trylock(&mlc->osem));

        if (mlc->opacket & HIL_DO_ALTER_CTRL)
                goto do_control;

 do_data:
        if (priv->emtestmode) {
                up(&mlc->osem);
                return 0;
        }
        /* Shouldn't be sending commands when loop may be busy */
        BUG_ON(down_trylock(&mlc->csem));
        up(&mlc->csem);

        priv->trans.actidx = 0;
        priv->trans.idx = 1;
        priv->trans.act.semaphore = &mlc->osem;
        priv->trans.endidx = 6;
        priv->tseq[0] =
                HP_SDC_ACT_DATAREG | HP_SDC_ACT_POSTCMD | HP_SDC_ACT_SEMAPHORE;
        priv->tseq[1] = 0x7;
        priv->tseq[2] =
                (mlc->opacket &
                 (HIL_PKT_ADDR_MASK | HIL_PKT_CMD))
                   >> HIL_PKT_ADDR_SHIFT;
        priv->tseq[3] =
                (mlc->opacket & HIL_PKT_DATA_MASK)
                  >> HIL_PKT_DATA_SHIFT;
        priv->tseq[4] = 0;  /* No timeout */
        if (priv->tseq[3] == HIL_CMD_DHR)
                priv->tseq[4] = 1;
        priv->tseq[5] = HP_SDC_CMD_DO_HIL;
        goto enqueue;

 do_control:
        priv->emtestmode = mlc->opacket & HIL_CTRL_TEST;

        /* we cannot emulate this, it should not be used. */
        BUG_ON((mlc->opacket & (HIL_CTRL_APE | HIL_CTRL_IPF)) == HIL_CTRL_APE);

        if ((mlc->opacket & HIL_CTRL_ONLY) == HIL_CTRL_ONLY)
                goto control_only;

        /* Should not send command/data after engaging APE */
        BUG_ON(mlc->opacket & HIL_CTRL_APE);

        /* Disengaging APE this way would not be valid either since
         * the loop must be allowed to idle.
         *
         * So, it works out that we really never actually send control
         * and data when using SDC, we just send the data.
         */
        goto do_data;

 control_only:
        priv->trans.actidx = 0;
        priv->trans.idx = 1;
        priv->trans.act.semaphore = &mlc->osem;
        priv->trans.endidx = 4;
        priv->tseq[0] =
          HP_SDC_ACT_PRECMD | HP_SDC_ACT_DATAOUT | HP_SDC_ACT_SEMAPHORE;
        priv->tseq[1] = HP_SDC_CMD_SET_LPC;
        priv->tseq[2] = 1;
        /* priv->tseq[3] = (mlc->ddc + 1) | HP_SDC_LPS_ACSUCC; */
        priv->tseq[3] = 0;
        if (mlc->opacket & HIL_CTRL_APE) {
                priv->tseq[3] |= HP_SDC_LPC_APE_IPF;
                BUG_ON(down_trylock(&mlc->csem));
        }
 enqueue:
        return hp_sdc_enqueue_transaction(&priv->trans);
}

static int __init hp_sdc_mlc_init(void)
{
        hil_mlc *mlc = &hp_sdc_mlc;
        int err;

#ifdef __mc68000__
        if (!MACH_IS_HP300)
                return -ENODEV;
#endif

        printk(KERN_INFO PREFIX "Registering the System Domain Controller's HIL MLC.\n");

        hp_sdc_mlc_priv.emtestmode = 0;
        hp_sdc_mlc_priv.trans.seq = hp_sdc_mlc_priv.tseq;
        hp_sdc_mlc_priv.trans.act.semaphore = &mlc->osem;
        hp_sdc_mlc_priv.got5x = 0;

        mlc->cts = &hp_sdc_mlc_cts;
        mlc->in = &hp_sdc_mlc_in;
        mlc->out = &hp_sdc_mlc_out;
        mlc->priv = &hp_sdc_mlc_priv;

        err = hil_mlc_register(mlc);
        if (err) {
                printk(KERN_WARNING PREFIX "Failed to register MLC structure with hil_mlc\n");
                return err;
        }

        if (hp_sdc_request_hil_irq(&hp_sdc_mlc_isr)) {
                printk(KERN_WARNING PREFIX "Request for raw HIL ISR hook denied\n");
                if (hil_mlc_unregister(mlc))
                        printk(KERN_ERR PREFIX "Failed to unregister MLC structure with hil_mlc.\n"
                                "This is bad.  Could cause an oops.\n");
                return -EBUSY;
        }

        return 0;
}

static void __exit hp_sdc_mlc_exit(void)
{
        hil_mlc *mlc = &hp_sdc_mlc;

        if (hp_sdc_release_hil_irq(&hp_sdc_mlc_isr))
                printk(KERN_ERR PREFIX "Failed to release the raw HIL ISR hook.\n"
                        "This is bad.  Could cause an oops.\n");

        if (hil_mlc_unregister(mlc))
                printk(KERN_ERR PREFIX "Failed to unregister MLC structure with hil_mlc.\n"
                        "This is bad.  Could cause an oops.\n");
}

module_init(hp_sdc_mlc_init);
module_exit(hp_sdc_mlc_exit);