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/*

 * xen console driver interface to hvc_console.c

 *

 * (c) 2007 Gerd Hoffmann <kraxel@suse.de>

 *

 * 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 <linux/console.h>

#include <linux/delay.h>

#include <linux/err.h>

#include <linux/init.h>

#include <linux/types.h>

#include <asm/xen/hypervisor.h>

#include <xen/page.h>

#include <xen/events.h>

#include <xen/interface/io/console.h>

#include <xen/hvc-console.h>

#include "hvc_console.h"

#define HVC_COOKIE   0x58656e /* "Xen" in hex */

static struct hvc_struct *hvc;

static int xencons_irq;

/* ------------------------------------------------------------------ */

static inline struct xencons_interface *xencons_interface(void)

{

        return mfn_to_virt(xen_start_info->console.domU.mfn);

}

static inline void notify_daemon(void)

{

        /* Use evtchn: this is called early, before irq is set up. */

        notify_remote_via_evtchn(xen_start_info->console.domU.evtchn);

}

static int write_console(uint32_t vtermno, const char *data, int len)

{

        struct xencons_interface *intf = xencons_interface();

        XENCONS_RING_IDX cons, prod;

        int sent = 0;

        cons = intf->out_cons;

        prod = intf->out_prod;

        mb();                   /* update queue values before going on */

        BUG_ON((prod - cons) > sizeof(intf->out));

        while ((sent < len) && ((prod - cons) < sizeof(intf->out)))

                intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++];

        wmb();                  /* write ring before updating pointer */

        intf->out_prod = prod;

        notify_daemon();

        return sent;

}

static int read_console(uint32_t vtermno, char *buf, int len)

{

        struct xencons_interface *intf = xencons_interface();

        XENCONS_RING_IDX cons, prod;

        int recv = 0;

        cons = intf->in_cons;

        prod = intf->in_prod;

        mb();                   /* get pointers before reading ring */

        BUG_ON((prod - cons) > sizeof(intf->in));

        while (cons != prod && recv < len)

                buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)];

        mb();                   /* read ring before consuming */

        intf->in_cons = cons;

        notify_daemon();

        return recv;

}

static struct hv_ops hvc_ops = {

        .get_chars = read_console,

        .put_chars = write_console,

};

static int __init xen_init(void)

{

        struct hvc_struct *hp;

        if (!is_running_on_xen())

                return 0;

        xencons_irq = bind_evtchn_to_irq(xen_start_info->console.domU.evtchn);

        if (xencons_irq < 0)

                xencons_irq = 0 /* NO_IRQ */;

        hp = hvc_alloc(HVC_COOKIE, xencons_irq, &hvc_ops, 256);

        if (IS_ERR(hp))

                return PTR_ERR(hp);

        hvc = hp;

        return 0;

}

static void __exit xen_fini(void)

{

        if (hvc)

                hvc_remove(hvc);

}

static int xen_cons_init(void)

{

        if (!is_running_on_xen())

                return 0;

        hvc_instantiate(HVC_COOKIE, 0, &hvc_ops);

        return 0;

}

module_init(xen_init);

module_exit(xen_fini);

console_initcall(xen_cons_init);

static void xenboot_write_console(struct console *console, const char *string,

                                  unsigned len)

{

        unsigned int linelen, off = 0;

        const char *pos;

        while (off < len && NULL != (pos = strchr(string+off, '\n'))) {

                linelen = pos-string+off;

                if (off + linelen > len)

                        break;

                write_console(0, string+off, linelen);

                write_console(0, "\r\n", 2);

                off += linelen + 1;

        }

        if (off < len)

                write_console(0, string+off, len-off);

}

struct console xenboot_console = {

        .name           = "xenboot",

        .write          = xenboot_write_console,

        .flags          = CON_PRINTBUFFER | CON_BOOT,

};