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hp_sdc_mlc.c

/*
 * 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 <asm/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");

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 "Unkown 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)) {
            struct timeval tv;
            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;
            }
            do_gettimeofday(&tv);
            tv.tv_usec += USEC_PER_SEC * (tv.tv_sec - mlc->instart.tv_sec);
            if (tv.tv_usec - mlc->instart.tv_usec > 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;
      __hp_sdc_enqueue_transaction(&priv->trans);
 busy:
      return 1;
 done:
      priv->trans.act.semaphore = &mlc->osem;
      up(&mlc->csem);
      return 0;
}

static void 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;
      }
      /* 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;
            down_trylock(&mlc->csem);
      }
 enqueue:
      hp_sdc_enqueue_transaction(&priv->trans);
}

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

      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;

      if (hil_mlc_register(mlc)) {
            printk(KERN_WARNING PREFIX "Failed to register MLC structure with hil_mlc\n");
            goto err0;
      }

      if (hp_sdc_request_hil_irq(&hp_sdc_mlc_isr)) {
            printk(KERN_WARNING PREFIX "Request for raw HIL ISR hook denied\n");
            goto err1;
      }
      return 0;
 err1:
      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");
 err0:
      return -EBUSY;
}

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);

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