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gscps2.c

/*
 * drivers/input/serio/gscps2.c
 *
 * Copyright (c) 2004-2006 Helge Deller <deller@gmx.de>
 * Copyright (c) 2002 Laurent Canet <canetl@esiee.fr>
 * Copyright (c) 2002 Thibaut Varene <varenet@parisc-linux.org>
 *
 * Pieces of code based on linux-2.4's hp_mouse.c & hp_keyb.c
 *    Copyright (c) 1999 Alex deVries <alex@onefishtwo.ca>
 *    Copyright (c) 1999-2000 Philipp Rumpf <prumpf@tux.org>
 *    Copyright (c) 2000 Xavier Debacker <debackex@esiee.fr>
 *    Copyright (c) 2000-2001 Thomas Marteau <marteaut@esiee.fr>
 *
 * HP GSC PS/2 port driver, found in PA/RISC Workstations
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * TODO:
 * - Dino testing (did HP ever shipped a machine on which this port
 *                 was usable/enabled ?)
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/serio.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/delay.h>
#include <linux/ioport.h>
#include <linux/pci_ids.h>

#include <asm/irq.h>
#include <asm/io.h>
#include <asm/parisc-device.h>

MODULE_AUTHOR("Laurent Canet <canetl@esiee.fr>, Thibaut Varene <varenet@parisc-linux.org>, Helge Deller <deller@gmx.de>");
MODULE_DESCRIPTION("HP GSC PS2 port driver");
MODULE_LICENSE("GPL");
MODULE_DEVICE_TABLE(parisc, gscps2_device_tbl);

#define PFX "gscps2.c: "

/*
 * Driver constants
 */

/* various constants */
#define ENABLE                1
#define DISABLE               0

#define GSC_DINO_OFFSET       0x0800      /* offset for DINO controller versus LASI one */

/* PS/2 IO port offsets */
#define GSC_ID                0x00  /* device ID offset (see: GSC_ID_XXX) */
#define GSC_RESET       0x00  /* reset port offset */
#define GSC_RCVDATA           0x04  /* receive port offset */
#define GSC_XMTDATA           0x04  /* transmit port offset */
#define GSC_CONTROL           0x08  /* see: Control register bits */
#define GSC_STATUS            0x0C  /* see: Status register bits */

/* Control register bits */
#define GSC_CTRL_ENBL         0x01  /* enable interface */
#define GSC_CTRL_LPBXR        0x02  /* loopback operation */
#define GSC_CTRL_DIAG         0x20  /* directly control clock/data line */
#define GSC_CTRL_DATDIR       0x40  /* data line direct control */
#define GSC_CTRL_CLKDIR       0x80  /* clock line direct control */

/* Status register bits */
#define GSC_STAT_RBNE         0x01  /* Receive Buffer Not Empty */
#define GSC_STAT_TBNE         0x02  /* Transmit Buffer Not Empty */
#define GSC_STAT_TERR         0x04  /* Timeout Error */
#define GSC_STAT_PERR         0x08  /* Parity Error */
#define GSC_STAT_CMPINTR      0x10  /* Composite Interrupt = irq on any port */
#define GSC_STAT_DATSHD       0x40  /* Data Line Shadow */
#define GSC_STAT_CLKSHD       0x80  /* Clock Line Shadow */

/* IDs returned by GSC_ID port register */
#define GSC_ID_KEYBOARD       0     /* device ID values */
#define GSC_ID_MOUSE          1


static irqreturn_t gscps2_interrupt(int irq, void *dev);

#define BUFFER_SIZE 0x0f

/* GSC PS/2 port device struct */
struct gscps2port {
      struct list_head node;
      struct parisc_device *padev;
      struct serio *port;
      spinlock_t lock;
      char *addr;
      u8 act, append; /* position in buffer[] */
      struct {
            u8 data;
            u8 str;
      } buffer[BUFFER_SIZE+1];
      int id;
};

/*
 * Various HW level routines
 */

#define gscps2_readb_input(x)       readb((x)+GSC_RCVDATA)
#define gscps2_readb_control(x)           readb((x)+GSC_CONTROL)
#define gscps2_readb_status(x)            readb((x)+GSC_STATUS)
#define gscps2_writeb_control(x, y) writeb((x), (y)+GSC_CONTROL)


/*
 * wait_TBE() - wait for Transmit Buffer Empty
 */

static int wait_TBE(char *addr)
{
      int timeout = 25000; /* device is expected to react within 250 msec */
      while (gscps2_readb_status(addr) & GSC_STAT_TBNE) {
            if (!--timeout)
                  return 0;   /* This should not happen */
            udelay(10);
      }
      return 1;
}


/*
 * gscps2_flush() - flush the receive buffer
 */

static void gscps2_flush(struct gscps2port *ps2port)
{
      while (gscps2_readb_status(ps2port->addr) & GSC_STAT_RBNE)
            gscps2_readb_input(ps2port->addr);
      ps2port->act = ps2port->append = 0;
}

/*
 * gscps2_writeb_output() - write a byte to the port
 *
 * returns 1 on sucess, 0 on error
 */

static inline int gscps2_writeb_output(struct gscps2port *ps2port, u8 data)
{
      unsigned long flags;
      char *addr = ps2port->addr;

      if (!wait_TBE(addr)) {
            printk(KERN_DEBUG PFX "timeout - could not write byte %#x\n", data);
            return 0;
      }

      while (gscps2_readb_status(ps2port->addr) & GSC_STAT_RBNE)
            /* wait */;

      spin_lock_irqsave(&ps2port->lock, flags);
      writeb(data, addr+GSC_XMTDATA);
      spin_unlock_irqrestore(&ps2port->lock, flags);

      /* this is ugly, but due to timing of the port it seems to be necessary. */
      mdelay(6);

      /* make sure any received data is returned as fast as possible */
      /* this is important e.g. when we set the LEDs on the keyboard */
      gscps2_interrupt(0, NULL);

      return 1;
}


/*
 * gscps2_enable() - enables or disables the port
 */

static void gscps2_enable(struct gscps2port *ps2port, int enable)
{
      unsigned long flags;
      u8 data;

      /* now enable/disable the port */
      spin_lock_irqsave(&ps2port->lock, flags);
      gscps2_flush(ps2port);
      data = gscps2_readb_control(ps2port->addr);
      if (enable)
            data |= GSC_CTRL_ENBL;
      else
            data &= ~GSC_CTRL_ENBL;
      gscps2_writeb_control(data, ps2port->addr);
      spin_unlock_irqrestore(&ps2port->lock, flags);
      wait_TBE(ps2port->addr);
      gscps2_flush(ps2port);
}

/*
 * gscps2_reset() - resets the PS/2 port
 */

static void gscps2_reset(struct gscps2port *ps2port)
{
      char *addr = ps2port->addr;
      unsigned long flags;

      /* reset the interface */
      spin_lock_irqsave(&ps2port->lock, flags);
      gscps2_flush(ps2port);
      writeb(0xff, addr+GSC_RESET);
      gscps2_flush(ps2port);
      spin_unlock_irqrestore(&ps2port->lock, flags);
}

static LIST_HEAD(ps2port_list);

/**
 * gscps2_interrupt() - Interruption service routine
 *
 * This function reads received PS/2 bytes and processes them on
 * all interfaces.
 * The problematic part here is, that the keyboard and mouse PS/2 port
 * share the same interrupt and it's not possible to send data if any
 * one of them holds input data. To solve this problem we try to receive
 * the data as fast as possible and handle the reporting to the upper layer
 * later.
 */

static irqreturn_t gscps2_interrupt(int irq, void *dev)
{
      struct gscps2port *ps2port;

      list_for_each_entry(ps2port, &ps2port_list, node) {

        unsigned long flags;
        spin_lock_irqsave(&ps2port->lock, flags);

        while ( (ps2port->buffer[ps2port->append].str =
               gscps2_readb_status(ps2port->addr)) & GSC_STAT_RBNE ) {
            ps2port->buffer[ps2port->append].data =
                        gscps2_readb_input(ps2port->addr);
            ps2port->append = ((ps2port->append+1) & BUFFER_SIZE);
        }

        spin_unlock_irqrestore(&ps2port->lock, flags);

      } /* list_for_each_entry */

      /* all data was read from the ports - now report the data to upper layer */

      list_for_each_entry(ps2port, &ps2port_list, node) {

        while (ps2port->act != ps2port->append) {

          unsigned int rxflags;
          u8 data, status;

          /* Did new data arrived while we read existing data ?
             If yes, exit now and let the new irq handler start over again */
          if (gscps2_readb_status(ps2port->addr) & GSC_STAT_CMPINTR)
            return IRQ_HANDLED;

          status = ps2port->buffer[ps2port->act].str;
          data   = ps2port->buffer[ps2port->act].data;

          ps2port->act = ((ps2port->act+1) & BUFFER_SIZE);
          rxflags =     ((status & GSC_STAT_TERR) ? SERIO_TIMEOUT : 0 ) |
                  ((status & GSC_STAT_PERR) ? SERIO_PARITY  : 0 );

          serio_interrupt(ps2port->port, data, rxflags);

        } /* while() */

      } /* list_for_each_entry */

      return IRQ_HANDLED;
}


/*
 * gscps2_write() - send a byte out through the aux interface.
 */

static int gscps2_write(struct serio *port, unsigned char data)
{
      struct gscps2port *ps2port = port->port_data;

      if (!gscps2_writeb_output(ps2port, data)) {
            printk(KERN_DEBUG PFX "sending byte %#x failed.\n", data);
            return -1;
      }
      return 0;
}

/*
 * gscps2_open() is called when a port is opened by the higher layer.
 * It resets and enables the port.
 */

static int gscps2_open(struct serio *port)
{
      struct gscps2port *ps2port = port->port_data;

      gscps2_reset(ps2port);

      /* enable it */
      gscps2_enable(ps2port, ENABLE);

      gscps2_interrupt(0, NULL);

      return 0;
}

/*
 * gscps2_close() disables the port
 */

static void gscps2_close(struct serio *port)
{
      struct gscps2port *ps2port = port->port_data;
      gscps2_enable(ps2port, DISABLE);
}

/**
 * gscps2_probe() - Probes PS2 devices
 * @return: success/error report
 */

static int __init gscps2_probe(struct parisc_device *dev)
{
      struct gscps2port *ps2port;
      struct serio *serio;
      unsigned long hpa = dev->hpa.start;
      int ret;

      if (!dev->irq)
            return -ENODEV;

      /* Offset for DINO PS/2. Works with LASI even */
      if (dev->id.sversion == 0x96)
            hpa += GSC_DINO_OFFSET;

      ps2port = kzalloc(sizeof(struct gscps2port), GFP_KERNEL);
      serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
      if (!ps2port || !serio) {
            ret = -ENOMEM;
            goto fail_nomem;
      }

      dev_set_drvdata(&dev->dev, ps2port);

      ps2port->port = serio;
      ps2port->padev = dev;
      ps2port->addr = ioremap_nocache(hpa, GSC_STATUS + 4);
      spin_lock_init(&ps2port->lock);

      gscps2_reset(ps2port);
      ps2port->id = readb(ps2port->addr + GSC_ID) & 0x0f;

      snprintf(serio->name, sizeof(serio->name), "GSC PS/2 %s",
             (ps2port->id == GSC_ID_KEYBOARD) ? "keyboard" : "mouse");
      strlcpy(serio->phys, dev->dev.bus_id, sizeof(serio->phys));
      serio->id.type          = SERIO_8042;
      serio->write            = gscps2_write;
      serio->open       = gscps2_open;
      serio->close            = gscps2_close;
      serio->port_data  = ps2port;
      serio->dev.parent = &dev->dev;

      ret = -EBUSY;
      if (request_irq(dev->irq, gscps2_interrupt, IRQF_SHARED, ps2port->port->name, ps2port))
            goto fail_miserably;

      if (ps2port->id != GSC_ID_KEYBOARD && ps2port->id != GSC_ID_MOUSE) {
            printk(KERN_WARNING PFX "Unsupported PS/2 port at 0x%08lx (id=%d) ignored\n",
                        hpa, ps2port->id);
            ret = -ENODEV;
            goto fail;
      }

#if 0
      if (!request_mem_region(hpa, GSC_STATUS + 4, ps2port->port.name))
            goto fail;
#endif

      printk(KERN_INFO "serio: %s port at 0x%p irq %d @ %s\n",
            ps2port->port->name,
            ps2port->addr,
            ps2port->padev->irq,
            ps2port->port->phys);

      serio_register_port(ps2port->port);

      list_add_tail(&ps2port->node, &ps2port_list);

      return 0;

fail:
      free_irq(dev->irq, ps2port);

fail_miserably:
      iounmap(ps2port->addr);
      release_mem_region(dev->hpa.start, GSC_STATUS + 4);

fail_nomem:
      kfree(ps2port);
      kfree(serio);
      return ret;
}

/**
 * gscps2_remove() - Removes PS2 devices
 * @return: success/error report
 */

static int __devexit gscps2_remove(struct parisc_device *dev)
{
      struct gscps2port *ps2port = dev_get_drvdata(&dev->dev);

      serio_unregister_port(ps2port->port);
      free_irq(dev->irq, ps2port);
      gscps2_flush(ps2port);
      list_del(&ps2port->node);
      iounmap(ps2port->addr);
#if 0
      release_mem_region(dev->hpa, GSC_STATUS + 4);
#endif
      dev_set_drvdata(&dev->dev, NULL);
      kfree(ps2port);
      return 0;
}


static struct parisc_device_id gscps2_device_tbl[] = {
      { HPHW_FIO, HVERSION_REV_ANY_ID, HVERSION_ANY_ID, 0x00084 }, /* LASI PS/2 */
#ifdef DINO_TESTED
      { HPHW_FIO, HVERSION_REV_ANY_ID, HVERSION_ANY_ID, 0x00096 }, /* DINO PS/2 */
#endif
      { 0, }      /* 0 terminated list */
};

static struct parisc_driver parisc_ps2_driver = {
      .name       = "gsc_ps2",
      .id_table   = gscps2_device_tbl,
      .probe            = gscps2_probe,
      .remove           = gscps2_remove,
};

static int __init gscps2_init(void)
{
      register_parisc_driver(&parisc_ps2_driver);
      return 0;
}

static void __exit gscps2_exit(void)
{
      unregister_parisc_driver(&parisc_ps2_driver);
}


module_init(gscps2_init);
module_exit(gscps2_exit);


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