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hvc_iseries.c

/*
 * iSeries vio driver interface to hvc_console.c
 *
 * This code is based heavily on hvc_vio.c and viocons.c
 *
 * Copyright (C) 2006 Stephen Rothwell, IBM Corporation
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */
#include <stdarg.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/console.h>

#include <asm/hvconsole.h>
#include <asm/vio.h>
#include <asm/prom.h>
#include <asm/firmware.h>
#include <asm/iseries/vio.h>
#include <asm/iseries/hv_call.h>
#include <asm/iseries/hv_lp_config.h>
#include <asm/iseries/hv_lp_event.h>

#include "hvc_console.h"

#define VTTY_PORTS 10

static DEFINE_SPINLOCK(consolelock);
static DEFINE_SPINLOCK(consoleloglock);

static const char hvc_driver_name[] = "hvc_console";

#define IN_BUF_SIZE     200

/*
 * Our port information.
 */
static struct port_info {
      HvLpIndex lp;
      u64 seq;    /* sequence number of last HV send */
      u64 ack;    /* last ack from HV */
      struct hvc_struct *hp;
      int in_start;
      int in_end;
      unsigned char in_buf[IN_BUF_SIZE];
} port_info[VTTY_PORTS] = {
      [ 0 ... VTTY_PORTS - 1 ] = {
            .lp = HvLpIndexInvalid
      }
};

#define viochar_is_console(pi)      ((pi) == &port_info[0])

static struct vio_device_id hvc_driver_table[] __devinitdata = {
      {"serial", "IBM,iSeries-vty"},
      { "", "" }
};
MODULE_DEVICE_TABLE(vio, hvc_driver_table);

static void hvlog(char *fmt, ...)
{
      int i;
      unsigned long flags;
      va_list args;
      static char buf[256];

      spin_lock_irqsave(&consoleloglock, flags);
      va_start(args, fmt);
      i = vscnprintf(buf, sizeof(buf) - 1, fmt, args);
      va_end(args);
      buf[i++] = '\r';
      HvCall_writeLogBuffer(buf, i);
      spin_unlock_irqrestore(&consoleloglock, flags);
}

/*
 * Initialize the common fields in a charLpEvent
 */
static void init_data_event(struct viocharlpevent *viochar, HvLpIndex lp)
{
      struct HvLpEvent *hev = &viochar->event;

      memset(viochar, 0, sizeof(struct viocharlpevent));

      hev->flags = HV_LP_EVENT_VALID | HV_LP_EVENT_DEFERRED_ACK |
            HV_LP_EVENT_INT;
      hev->xType = HvLpEvent_Type_VirtualIo;
      hev->xSubtype = viomajorsubtype_chario | viochardata;
      hev->xSourceLp = HvLpConfig_getLpIndex();
      hev->xTargetLp = lp;
      hev->xSizeMinus1 = sizeof(struct viocharlpevent);
      hev->xSourceInstanceId = viopath_sourceinst(lp);
      hev->xTargetInstanceId = viopath_targetinst(lp);
}

static int get_chars(uint32_t vtermno, char *buf, int count)
{
      struct port_info *pi;
      int n = 0;
      unsigned long flags;

      if (vtermno >= VTTY_PORTS)
            return -EINVAL;
      if (count == 0)
            return 0;

      pi = &port_info[vtermno];
      spin_lock_irqsave(&consolelock, flags);

      if (pi->in_end == 0)
            goto done;

      n = pi->in_end - pi->in_start;
      if (n > count)
            n = count;
      memcpy(buf, &pi->in_buf[pi->in_start], n);
      pi->in_start += n;
      if (pi->in_start == pi->in_end) {
            pi->in_start = 0;
            pi->in_end = 0;
      }
done:
      spin_unlock_irqrestore(&consolelock, flags);
      return n;
}

static int put_chars(uint32_t vtermno, const char *buf, int count)
{
      struct viocharlpevent *viochar;
      struct port_info *pi;
      HvLpEvent_Rc hvrc;
      unsigned long flags;
      int sent = 0;

      if (vtermno >= VTTY_PORTS)
            return -EINVAL;

      pi = &port_info[vtermno];

      spin_lock_irqsave(&consolelock, flags);

      if (viochar_is_console(pi) && !viopath_isactive(pi->lp)) {
            HvCall_writeLogBuffer(buf, count);
            sent = count;
            goto done;
      }

      viochar = vio_get_event_buffer(viomajorsubtype_chario);
      if (viochar == NULL) {
            hvlog("\n\rviocons: Can't get viochar buffer.");
            goto done;
      }

      while ((count > 0) && ((pi->seq - pi->ack) < VIOCHAR_WINDOW)) {
            int len;

            len = (count > VIOCHAR_MAX_DATA) ? VIOCHAR_MAX_DATA : count;

            if (viochar_is_console(pi))
                  HvCall_writeLogBuffer(buf, len);

            init_data_event(viochar, pi->lp);

            viochar->len = len;
            viochar->event.xCorrelationToken = pi->seq++;
            viochar->event.xSizeMinus1 =
                  offsetof(struct viocharlpevent, data) + len;

            memcpy(viochar->data, buf, len);

            hvrc = HvCallEvent_signalLpEvent(&viochar->event);
            if (hvrc)
                  hvlog("\n\rerror sending event! return code %d\n\r",
                        (int)hvrc);
            sent += len;
            count -= len;
            buf += len;
      }

      vio_free_event_buffer(viomajorsubtype_chario, viochar);
done:
      spin_unlock_irqrestore(&consolelock, flags);
      return sent;
}

static struct hv_ops hvc_get_put_ops = {
      .get_chars = get_chars,
      .put_chars = put_chars,
};

static int __devinit hvc_vio_probe(struct vio_dev *vdev,
                  const struct vio_device_id *id)
{
      struct hvc_struct *hp;
      struct port_info *pi;

      /* probed with invalid parameters. */
      if (!vdev || !id)
            return -EPERM;

      if (vdev->unit_address >= VTTY_PORTS)
            return -ENODEV;

      pi = &port_info[vdev->unit_address];

      hp = hvc_alloc(vdev->unit_address, vdev->irq, &hvc_get_put_ops,
                  VIOCHAR_MAX_DATA);
      if (IS_ERR(hp))
            return PTR_ERR(hp);
      pi->hp = hp;
      dev_set_drvdata(&vdev->dev, pi);

      return 0;
}

static int __devexit hvc_vio_remove(struct vio_dev *vdev)
{
      struct port_info *pi = dev_get_drvdata(&vdev->dev);
      struct hvc_struct *hp = pi->hp;

      return hvc_remove(hp);
}

static struct vio_driver hvc_vio_driver = {
      .id_table   = hvc_driver_table,
      .probe            = hvc_vio_probe,
      .remove           = hvc_vio_remove,
      .driver           = {
            .name = hvc_driver_name,
            .owner      = THIS_MODULE,
      }
};

static void hvc_open_event(struct HvLpEvent *event)
{
      unsigned long flags;
      struct viocharlpevent *cevent = (struct viocharlpevent *)event;
      u8 port = cevent->virtual_device;
      struct port_info *pi;
      int reject = 0;

      if (hvlpevent_is_ack(event)) {
            if (port >= VTTY_PORTS)
                  return;

            spin_lock_irqsave(&consolelock, flags);

            pi = &port_info[port];
            if (event->xRc == HvLpEvent_Rc_Good) {
                  pi->seq = pi->ack = 0;
                  /*
                   * This line allows connections from the primary
                   * partition but once one is connected from the
                   * primary partition nothing short of a reboot
                   * of linux will allow access from the hosting
                   * partition again without a required iSeries fix.
                   */
                  pi->lp = event->xTargetLp;
            }

            spin_unlock_irqrestore(&consolelock, flags);
            if (event->xRc != HvLpEvent_Rc_Good)
                  printk(KERN_WARNING
                         "hvc: handle_open_event: event->xRc == (%d).\n",
                         event->xRc);

            if (event->xCorrelationToken != 0) {
                  atomic_t *aptr= (atomic_t *)event->xCorrelationToken;
                  atomic_set(aptr, 1);
            } else
                  printk(KERN_WARNING
                         "hvc: weird...got open ack without atomic\n");
            return;
      }

      /* This had better require an ack, otherwise complain */
      if (!hvlpevent_need_ack(event)) {
            printk(KERN_WARNING "hvc: viocharopen without ack bit!\n");
            return;
      }

      spin_lock_irqsave(&consolelock, flags);

      /* Make sure this is a good virtual tty */
      if (port >= VTTY_PORTS) {
            event->xRc = HvLpEvent_Rc_SubtypeError;
            cevent->subtype_result_code = viorc_openRejected;
            /*
             * Flag state here since we can't printk while holding
             * the consolelock spinlock.
             */
            reject = 1;
      } else {
            pi = &port_info[port];
            if ((pi->lp != HvLpIndexInvalid) &&
                        (pi->lp != event->xSourceLp)) {
                  /*
                   * If this is tty is already connected to a different
                   * partition, fail.
                   */
                  event->xRc = HvLpEvent_Rc_SubtypeError;
                  cevent->subtype_result_code = viorc_openRejected;
                  reject = 2;
            } else {
                  pi->lp = event->xSourceLp;
                  event->xRc = HvLpEvent_Rc_Good;
                  cevent->subtype_result_code = viorc_good;
                  pi->seq = pi->ack = 0;
            }
      }

      spin_unlock_irqrestore(&consolelock, flags);

      if (reject == 1)
            printk(KERN_WARNING "hvc: open rejected: bad virtual tty.\n");
      else if (reject == 2)
            printk(KERN_WARNING "hvc: open rejected: console in exclusive "
                        "use by another partition.\n");

      /* Return the acknowledgement */
      HvCallEvent_ackLpEvent(event);
}

/*
 * Handle a close charLpEvent.  This should ONLY be an Interrupt because the
 * virtual console should never actually issue a close event to the hypervisor
 * because the virtual console never goes away.  A close event coming from the
 * hypervisor simply means that there are no client consoles connected to the
 * virtual console.
 */
static void hvc_close_event(struct HvLpEvent *event)
{
      unsigned long flags;
      struct viocharlpevent *cevent = (struct viocharlpevent *)event;
      u8 port = cevent->virtual_device;

      if (!hvlpevent_is_int(event)) {
            printk(KERN_WARNING
                  "hvc: got unexpected close acknowlegement\n");
            return;
      }

      if (port >= VTTY_PORTS) {
            printk(KERN_WARNING
                  "hvc: close message from invalid virtual device.\n");
            return;
      }

      /* For closes, just mark the console partition invalid */
      spin_lock_irqsave(&consolelock, flags);

      if (port_info[port].lp == event->xSourceLp)
            port_info[port].lp = HvLpIndexInvalid;

      spin_unlock_irqrestore(&consolelock, flags);
}

static void hvc_data_event(struct HvLpEvent *event)
{
      unsigned long flags;
      struct viocharlpevent *cevent = (struct viocharlpevent *)event;
      struct port_info *pi;
      int n;
      u8 port = cevent->virtual_device;

      if (port >= VTTY_PORTS) {
            printk(KERN_WARNING "hvc: data on invalid virtual device %d\n",
                        port);
            return;
      }
      if (cevent->len == 0)
            return;

      /*
       * Change 05/01/2003 - Ryan Arnold: If a partition other than
       * the current exclusive partition tries to send us data
       * events then just drop them on the floor because we don't
       * want his stinking data.  He isn't authorized to receive
       * data because he wasn't the first one to get the console,
       * therefore he shouldn't be allowed to send data either.
       * This will work without an iSeries fix.
       */
      pi = &port_info[port];
      if (pi->lp != event->xSourceLp)
            return;

      spin_lock_irqsave(&consolelock, flags);

      n = IN_BUF_SIZE - pi->in_end;
      if (n > cevent->len)
            n = cevent->len;
      if (n > 0) {
            memcpy(&pi->in_buf[pi->in_end], cevent->data, n);
            pi->in_end += n;
      }
      spin_unlock_irqrestore(&consolelock, flags);
      if (n == 0)
            printk(KERN_WARNING "hvc: input buffer overflow\n");
}

static void hvc_ack_event(struct HvLpEvent *event)
{
      struct viocharlpevent *cevent = (struct viocharlpevent *)event;
      unsigned long flags;
      u8 port = cevent->virtual_device;

      if (port >= VTTY_PORTS) {
            printk(KERN_WARNING "hvc: data on invalid virtual device\n");
            return;
      }

      spin_lock_irqsave(&consolelock, flags);
      port_info[port].ack = event->xCorrelationToken;
      spin_unlock_irqrestore(&consolelock, flags);
}

static void hvc_config_event(struct HvLpEvent *event)
{
      struct viocharlpevent *cevent = (struct viocharlpevent *)event;

      if (cevent->data[0] == 0x01)
            printk(KERN_INFO "hvc: window resized to %d: %d: %d: %d\n",
                   cevent->data[1], cevent->data[2],
                   cevent->data[3], cevent->data[4]);
      else
            printk(KERN_WARNING "hvc: unknown config event\n");
}

static void hvc_handle_event(struct HvLpEvent *event)
{
      int charminor;

      if (event == NULL)
            return;

      charminor = event->xSubtype & VIOMINOR_SUBTYPE_MASK;
      switch (charminor) {
      case viocharopen:
            hvc_open_event(event);
            break;
      case viocharclose:
            hvc_close_event(event);
            break;
      case viochardata:
            hvc_data_event(event);
            break;
      case viocharack:
            hvc_ack_event(event);
            break;
      case viocharconfig:
            hvc_config_event(event);
            break;
      default:
            if (hvlpevent_is_int(event) && hvlpevent_need_ack(event)) {
                  event->xRc = HvLpEvent_Rc_InvalidSubtype;
                  HvCallEvent_ackLpEvent(event);
            }
      }
}

static int __init send_open(HvLpIndex remoteLp, void *sem)
{
      return HvCallEvent_signalLpEventFast(remoteLp,
                  HvLpEvent_Type_VirtualIo,
                  viomajorsubtype_chario | viocharopen,
                  HvLpEvent_AckInd_DoAck, HvLpEvent_AckType_ImmediateAck,
                  viopath_sourceinst(remoteLp),
                  viopath_targetinst(remoteLp),
                  (u64)(unsigned long)sem, VIOVERSION << 16,
                  0, 0, 0, 0);
}

static int __init hvc_vio_init(void)
{
      atomic_t wait_flag;
      int rc;

      if (!firmware_has_feature(FW_FEATURE_ISERIES))
            return -EIO;

      /* +2 for fudge */
      rc = viopath_open(HvLpConfig_getPrimaryLpIndex(),
                  viomajorsubtype_chario, VIOCHAR_WINDOW + 2);
      if (rc)
            printk(KERN_WARNING "hvc: error opening to primary %d\n", rc);

      if (viopath_hostLp == HvLpIndexInvalid)
            vio_set_hostlp();

      /*
       * And if the primary is not the same as the hosting LP, open to the
       * hosting lp
       */
      if ((viopath_hostLp != HvLpIndexInvalid) &&
          (viopath_hostLp != HvLpConfig_getPrimaryLpIndex())) {
            printk(KERN_INFO "hvc: open path to hosting (%d)\n",
                        viopath_hostLp);
            rc = viopath_open(viopath_hostLp, viomajorsubtype_chario,
                        VIOCHAR_WINDOW + 2);    /* +2 for fudge */
            if (rc)
                  printk(KERN_WARNING
                        "error opening to partition %d: %d\n",
                        viopath_hostLp, rc);
      }

      if (vio_setHandler(viomajorsubtype_chario, hvc_handle_event) < 0)
            printk(KERN_WARNING
                  "hvc: error seting handler for console events!\n");

      /*
       * First, try to open the console to the hosting lp.
       * Wait on a semaphore for the response.
       */
      atomic_set(&wait_flag, 0);
      if ((viopath_isactive(viopath_hostLp)) &&
          (send_open(viopath_hostLp, &wait_flag) == 0)) {
            printk(KERN_INFO "hvc: hosting partition %d\n", viopath_hostLp);
            while (atomic_read(&wait_flag) == 0)
                  mb();
            atomic_set(&wait_flag, 0);
      }

      /*
       * If we don't have an active console, try the primary
       */
      if ((!viopath_isactive(port_info[0].lp)) &&
          (viopath_isactive(HvLpConfig_getPrimaryLpIndex())) &&
          (send_open(HvLpConfig_getPrimaryLpIndex(), &wait_flag) == 0)) {
            printk(KERN_INFO "hvc: opening console to primary partition\n");
            while (atomic_read(&wait_flag) == 0)
                  mb();
      }

      /* Register as a vio device to receive callbacks */
      rc = vio_register_driver(&hvc_vio_driver);

      return rc;
}
module_init(hvc_vio_init); /* after drivers/char/hvc_console.c */

static void __exit hvc_vio_exit(void)
{
      vio_unregister_driver(&hvc_vio_driver);
}
module_exit(hvc_vio_exit);

/* the device tree order defines our numbering */
static int __init hvc_find_vtys(void)
{
      struct device_node *vty;
      int num_found = 0;

      for (vty = of_find_node_by_name(NULL, "vty"); vty != NULL;
                  vty = of_find_node_by_name(vty, "vty")) {
            const uint32_t *vtermno;

            /* We have statically defined space for only a certain number
             * of console adapters.
             */
            if ((num_found >= MAX_NR_HVC_CONSOLES) ||
                        (num_found >= VTTY_PORTS))
                  break;

            vtermno = of_get_property(vty, "reg", NULL);
            if (!vtermno)
                  continue;

            if (!of_device_is_compatible(vty, "IBM,iSeries-vty"))
                  continue;

            if (num_found == 0)
                  add_preferred_console("hvc", 0, NULL);
            hvc_instantiate(*vtermno, num_found, &hvc_get_put_ops);
            ++num_found;
      }

      return num_found;
}
console_initcall(hvc_find_vtys);

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