/*
 * 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,
        .notifier_add = notifier_add_irq,
        .notifier_del = notifier_del_irq,
        .notifier_hangup = notifier_hangup_irq,
};

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         = __devexit_p(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)) {
                        of_node_put(vty);
                        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);