hvc_vio.c

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/*
 * vio driver interface to hvc_console.c
 *
 * This code was moved here to allow the remaining code to be reused as a
 * generic polling mode with semi-reliable transport driver core to the
 * console and tty subsystems.
 *
 *
 * Copyright (C) 2001 Anton Blanchard <[email protected]>, IBM
 * Copyright (C) 2001 Paul Mackerras <[email protected]>, IBM
 * Copyright (C) 2004 Benjamin Herrenschmidt <[email protected]>, IBM Corp.
 * Copyright (C) 2004 IBM Corporation
 *
 * Additional Author(s):
 *  Ryan S. Arnold <[email protected]>
 *
 * 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
 *
 * TODO:
 *
 *   - handle error in sending hvsi protocol packets
 *   - retry nego on subsequent sends ?
 */

#undef DEBUG

#include <linux/types.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/console.h>
#include <linux/module.h>

#include <asm/hvconsole.h>
#include <asm/vio.h>
#include <asm/prom.h>
#include <asm/hvsi.h>
#include <asm/udbg.h>

#include "hvc_console.h"

static const char hvc_driver_name[] = "hvc_console";

static struct vio_device_id hvc_driver_table[] __devinitdata = {
    {"serial", "hvterm1"},
#ifndef HVC_OLD_HVSI
    {"serial", "hvterm-protocol"},
#endif
    { "", "" }
};
MODULE_DEVICE_TABLE(vio, hvc_driver_table);

typedef enum hv_protocol {
    HV_PROTOCOL_RAW,
    HV_PROTOCOL_HVSI
} hv_protocol_t;

struct hvterm_priv {
    u32         termno; /* HV term number */
    hv_protocol_t       proto;  /* Raw data or HVSI packets */
    struct hvsi_priv    hvsi;   /* HVSI specific data */
    spinlock_t      buf_lock;
    char            buf[SIZE_VIO_GET_CHARS];
    int         left;
    int         offset;
};
static struct hvterm_priv *hvterm_privs[MAX_NR_HVC_CONSOLES];
/* For early boot console */
static struct hvterm_priv hvterm_priv0;

static int hvterm_raw_get_chars(uint32_t vtermno, char *buf, int count)
{
    struct hvterm_priv *pv = hvterm_privs[vtermno];
    unsigned long i;
    unsigned long flags;
    int got;

    if (WARN_ON(!pv))
        return 0;

    spin_lock_irqsave(&pv->buf_lock, flags);

    if (pv->left == 0) {
        pv->offset = 0;
        pv->left = hvc_get_chars(pv->termno, pv->buf, count);

        /*
         * Work around a HV bug where it gives us a null
         * after every \r.  -- paulus
         */
        for (i = 1; i < pv->left; ++i) {
            if (pv->buf[i] == 0 && pv->buf[i-1] == '\r') {
                --pv->left;
                if (i < pv->left) {
                    memmove(&pv->buf[i], &pv->buf[i+1],
                        pv->left - i);
                }
            }
        }
    }

    got = min(count, pv->left);
    memcpy(buf, &pv->buf[pv->offset], got);
    pv->offset += got;
    pv->left -= got;

    spin_unlock_irqrestore(&pv->buf_lock, flags);

    return got;
}

static int hvterm_raw_put_chars(uint32_t vtermno, const char *buf, int count)
{
    struct hvterm_priv *pv = hvterm_privs[vtermno];

    if (WARN_ON(!pv))
        return 0;

    return hvc_put_chars(pv->termno, buf, count);
}

static const struct hv_ops hvterm_raw_ops = {
    .get_chars = hvterm_raw_get_chars,
    .put_chars = hvterm_raw_put_chars,
    .notifier_add = notifier_add_irq,
    .notifier_del = notifier_del_irq,
    .notifier_hangup = notifier_hangup_irq,
};

static int hvterm_hvsi_get_chars(uint32_t vtermno, char *buf, int count)
{
    struct hvterm_priv *pv = hvterm_privs[vtermno];

    if (WARN_ON(!pv))
        return 0;

    return hvsilib_get_chars(&pv->hvsi, buf, count);
}

static int hvterm_hvsi_put_chars(uint32_t vtermno, const char *buf, int count)
{
    struct hvterm_priv *pv = hvterm_privs[vtermno];

    if (WARN_ON(!pv))
        return 0;

    return hvsilib_put_chars(&pv->hvsi, buf, count);
}

static int hvterm_hvsi_open(struct hvc_struct *hp, int data)
{
    struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
    int rc;

    pr_devel("HVSI@%x: open !\n", pv->termno);

    rc = notifier_add_irq(hp, data);
    if (rc)
        return rc;

    return hvsilib_open(&pv->hvsi, hp);
}

static void hvterm_hvsi_close(struct hvc_struct *hp, int data)
{
    struct hvterm_priv *pv = hvterm_privs[hp->vtermno];

    pr_devel("HVSI@%x: do close !\n", pv->termno);

    hvsilib_close(&pv->hvsi, hp);

    notifier_del_irq(hp, data);
}

void hvterm_hvsi_hangup(struct hvc_struct *hp, int data)
{
    struct hvterm_priv *pv = hvterm_privs[hp->vtermno];

    pr_devel("HVSI@%x: do hangup !\n", pv->termno);

    hvsilib_close(&pv->hvsi, hp);

    notifier_hangup_irq(hp, data);
}

static int hvterm_hvsi_tiocmget(struct hvc_struct *hp)
{
    struct hvterm_priv *pv = hvterm_privs[hp->vtermno];

    if (!pv)
        return -EINVAL;
    return pv->hvsi.mctrl;
}

static int hvterm_hvsi_tiocmset(struct hvc_struct *hp, unsigned int set,
                unsigned int clear)
{
    struct hvterm_priv *pv = hvterm_privs[hp->vtermno];

    pr_devel("HVSI@%x: Set modem control, set=%x,clr=%x\n",
         pv->termno, set, clear);

    if (set & TIOCM_DTR)
        hvsilib_write_mctrl(&pv->hvsi, 1);
    else if (clear & TIOCM_DTR)
        hvsilib_write_mctrl(&pv->hvsi, 0);

    return 0;
}

static const struct hv_ops hvterm_hvsi_ops = {
    .get_chars = hvterm_hvsi_get_chars,
    .put_chars = hvterm_hvsi_put_chars,
    .notifier_add = hvterm_hvsi_open,
    .notifier_del = hvterm_hvsi_close,
    .notifier_hangup = hvterm_hvsi_hangup,
    .tiocmget = hvterm_hvsi_tiocmget,
    .tiocmset = hvterm_hvsi_tiocmset,
};

static void udbg_hvc_putc(char c)
{
    int count = -1;

    if (!hvterm_privs[0])
        return;

    if (c == '\n')
        udbg_hvc_putc('\r');

    do {
        switch(hvterm_privs[0]->proto) {
        case HV_PROTOCOL_RAW:
            count = hvterm_raw_put_chars(0, &c, 1);
            break;
        case HV_PROTOCOL_HVSI:
            count = hvterm_hvsi_put_chars(0, &c, 1);
            break;
        }
    } while(count == 0);
}

static int udbg_hvc_getc_poll(void)
{
    int rc = 0;
    char c;

    if (!hvterm_privs[0])
        return -1;

    switch(hvterm_privs[0]->proto) {
    case HV_PROTOCOL_RAW:
        rc = hvterm_raw_get_chars(0, &c, 1);
        break;
    case HV_PROTOCOL_HVSI:
        rc = hvterm_hvsi_get_chars(0, &c, 1);
        break;
    }
    if (!rc)
        return -1;
    return c;
}

static int udbg_hvc_getc(void)
{
    int ch;

    if (!hvterm_privs[0])
        return -1;

    for (;;) {
        ch = udbg_hvc_getc_poll();
        if (ch == -1) {
            /* This shouldn't be needed...but... */
            volatile unsigned long delay;
            for (delay=0; delay < 2000000; delay++)
                ;
        } else {
            return ch;
        }
    }
}

static int __devinit hvc_vio_probe(struct vio_dev *vdev,
                   const struct vio_device_id *id)
{
    const struct hv_ops *ops;
    struct hvc_struct *hp;
    struct hvterm_priv *pv;
    hv_protocol_t proto;
    int i, termno = -1;

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

    if (of_device_is_compatible(vdev->dev.of_node, "hvterm1")) {
        proto = HV_PROTOCOL_RAW;
        ops = &hvterm_raw_ops;
    } else if (of_device_is_compatible(vdev->dev.of_node, "hvterm-protocol")) {
        proto = HV_PROTOCOL_HVSI;
        ops = &hvterm_hvsi_ops;
    } else {
        pr_err("hvc_vio: Unkown protocol for %s\n", vdev->dev.of_node->full_name);
        return -ENXIO;
    }

    pr_devel("hvc_vio_probe() device %s, using %s protocol\n",
         vdev->dev.of_node->full_name,
         proto == HV_PROTOCOL_RAW ? "raw" : "hvsi");

    /* Is it our boot one ? */
    if (hvterm_privs[0] == &hvterm_priv0 &&
        vdev->unit_address == hvterm_priv0.termno) {
        pv = hvterm_privs[0];
        termno = 0;
        pr_devel("->boot console, using termno 0\n");
    }
    /* nope, allocate a new one */
    else {
        for (i = 0; i < MAX_NR_HVC_CONSOLES && termno < 0; i++)
            if (!hvterm_privs[i])
                termno = i;
        pr_devel("->non-boot console, using termno %d\n", termno);
        if (termno < 0)
            return -ENODEV;
        pv = kzalloc(sizeof(struct hvterm_priv), GFP_KERNEL);
        if (!pv)
            return -ENOMEM;
        pv->termno = vdev->unit_address;
        pv->proto = proto;
        spin_lock_init(&pv->buf_lock);
        hvterm_privs[termno] = pv;
        hvsilib_init(&pv->hvsi, hvc_get_chars, hvc_put_chars,
                 pv->termno, 0);
    }

    hp = hvc_alloc(termno, vdev->irq, ops, MAX_VIO_PUT_CHARS);
    if (IS_ERR(hp))
        return PTR_ERR(hp);
    dev_set_drvdata(&vdev->dev, hp);

    /* register udbg if it's not there already for console 0 */
    if (hp->index == 0 && !udbg_putc) {
        udbg_putc = udbg_hvc_putc;
        udbg_getc = udbg_hvc_getc;
        udbg_getc_poll = udbg_hvc_getc_poll;
    }

    return 0;
}

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

    termno = hp->vtermno;
    rc = hvc_remove(hp);
    if (rc == 0) {
        if (hvterm_privs[termno] != &hvterm_priv0)
            kfree(hvterm_privs[termno]);
        hvterm_privs[termno] = NULL;
    }
    return rc;
}

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

static int __init hvc_vio_init(void)
{
    int rc;

    /* 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);

void __init hvc_vio_init_early(void)
{
    struct device_node *stdout_node;
    const u32 *termno;
    const char *name;
    const struct hv_ops *ops;

    /* find the boot console from /chosen/stdout */
    if (!of_chosen)
        return;
    name = of_get_property(of_chosen, "linux,stdout-path", NULL);
    if (name == NULL)
        return;
    stdout_node = of_find_node_by_path(name);
    if (!stdout_node)
        return;
    name = of_get_property(stdout_node, "name", NULL);
    if (!name) {
        printk(KERN_WARNING "stdout node missing 'name' property!\n");
        goto out;
    }

    /* Check if it's a virtual terminal */
    if (strncmp(name, "vty", 3) != 0)
        goto out;
    termno = of_get_property(stdout_node, "reg", NULL);
    if (termno == NULL)
        goto out;
    hvterm_priv0.termno = *termno;
    spin_lock_init(&hvterm_priv0.buf_lock);
    hvterm_privs[0] = &hvterm_priv0;

    /* Check the protocol */
    if (of_device_is_compatible(stdout_node, "hvterm1")) {
        hvterm_priv0.proto = HV_PROTOCOL_RAW;
        ops = &hvterm_raw_ops;
    }
    else if (of_device_is_compatible(stdout_node, "hvterm-protocol")) {
        hvterm_priv0.proto = HV_PROTOCOL_HVSI;
        ops = &hvterm_hvsi_ops;
        hvsilib_init(&hvterm_priv0.hvsi, hvc_get_chars, hvc_put_chars,
                 hvterm_priv0.termno, 1);
        /* HVSI, perform the handshake now */
        hvsilib_establish(&hvterm_priv0.hvsi);
    } else
        goto out;
    udbg_putc = udbg_hvc_putc;
    udbg_getc = udbg_hvc_getc;
    udbg_getc_poll = udbg_hvc_getc_poll;
#ifdef HVC_OLD_HVSI
    /* When using the old HVSI driver don't register the HVC
     * backend for HVSI, only do udbg
     */
    if (hvterm_priv0.proto == HV_PROTOCOL_HVSI)
        goto out;
#endif
    add_preferred_console("hvc", 0, NULL);
    hvc_instantiate(0, 0, ops);
out:
    of_node_put(stdout_node);
}

/* call this from early_init() for a working debug console on
 * vterm capable LPAR machines
 */
#ifdef CONFIG_PPC_EARLY_DEBUG_LPAR
void __init udbg_init_debug_lpar(void)
{
    hvterm_privs[0] = &hvterm_priv0;
    hvterm_priv0.termno = 0;
    hvterm_priv0.proto = HV_PROTOCOL_RAW;
    spin_lock_init(&hvterm_priv0.buf_lock);
    udbg_putc = udbg_hvc_putc;
    udbg_getc = udbg_hvc_getc;
    udbg_getc_poll = udbg_hvc_getc_poll;
}
#endif /* CONFIG_PPC_EARLY_DEBUG_LPAR */

#ifdef CONFIG_PPC_EARLY_DEBUG_LPAR_HVSI
void __init udbg_init_debug_lpar_hvsi(void)
{
    hvterm_privs[0] = &hvterm_priv0;
    hvterm_priv0.termno = CONFIG_PPC_EARLY_DEBUG_HVSI_VTERMNO;
    hvterm_priv0.proto = HV_PROTOCOL_HVSI;
    spin_lock_init(&hvterm_priv0.buf_lock);
    udbg_putc = udbg_hvc_putc;
    udbg_getc = udbg_hvc_getc;
    udbg_getc_poll = udbg_hvc_getc_poll;
    hvsilib_init(&hvterm_priv0.hvsi, hvc_get_chars, hvc_put_chars,
             hvterm_priv0.termno, 1);
    hvsilib_establish(&hvterm_priv0.hvsi);
}
#endif /* CONFIG_PPC_EARLY_DEBUG_LPAR_HVSI */