LXR linux/drivers/char/hvc

   1/*
   2 * Beat hypervisor console driver
   3 *
   4 * (C) Copyright 2006 TOSHIBA CORPORATION
   5 *
   6 * This code is based on drivers/char/hvc_rtas.c:
   7 * (C) Copyright IBM Corporation 2001-2005
   8 * (C) Copyright Red Hat, Inc. 2005
   9 *
  10 * This program is free software; you can redistribute it and/or modify
  11 * it under the terms of the GNU General Public License as published by
  12 * the Free Software Foundation; either version 2 of the License, or
  13 * (at your option) any later version.
  14 *
  15 * This program is distributed in the hope that it will be useful,
  16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 * GNU General Public License for more details.
  19 *
  20 * You should have received a copy of the GNU General Public License along
  21 * with this program; if not, write to the Free Software Foundation, Inc.,
  22 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  23 */
  24
  25#include <linux/module.h>
  26#include <linux/init.h>
  27#include <linux/err.h>
  28#include <linux/string.h>
  29#include <linux/console.h>
  30#include <asm/prom.h>
  31#include <asm/hvconsole.h>
  32#include <asm/firmware.h>
  33
  34#include "hvc_console.h"
  35
  36extern int64_t beat_get_term_char(uint64_t, uint64_t *, uint64_t *, uint64_t *);
  37extern int64_t beat_put_term_char(uint64_t, uint64_t, uint64_t, uint64_t);
  38
  39struct hvc_struct *hvc_beat_dev = NULL;
  40
  41/* bug: only one queue is available regardless of vtermno */
  42static int hvc_beat_get_chars(uint32_t vtermno, char *buf, int cnt)
  43{
  44        static unsigned char q[sizeof(unsigned long) * 2]
  45                __attribute__((aligned(sizeof(unsigned long))));
  46        static int qlen = 0;
  47        u64 got;
  48
  49again:
  50        if (qlen) {
  51                if (qlen > cnt) {
  52                        memcpy(buf, q, cnt);
  53                        qlen -= cnt;
  54                        memmove(q + cnt, q, qlen);
  55                        return cnt;
  56                } else {        /* qlen <= cnt */
  57                        int     r;
  58
  59                        memcpy(buf, q, qlen);
  60                        r = qlen;
  61                        qlen = 0;
  62                        return r;
  63                }
  64        }
  65        if (beat_get_term_char(vtermno, &got,
  66                ((u64 *)q), ((u64 *)q) + 1) == 0) {
  67                qlen = got;
  68                goto again;
  69        }
  70        return 0;
  71}
  72
  73static int hvc_beat_put_chars(uint32_t vtermno, const char *buf, int cnt)
  74{
  75        unsigned long kb[2];
  76        int rest, nlen;
  77
  78        for (rest = cnt; rest > 0; rest -= nlen) {
  79                nlen = (rest > 16) ? 16 : rest;
  80                memcpy(kb, buf, nlen);
  81                beat_put_term_char(vtermno, nlen, kb[0], kb[1]);
  82                buf += nlen;
  83        }
  84        return cnt;
  85}
  86
  87static struct hv_ops hvc_beat_get_put_ops = {
  88        .get_chars = hvc_beat_get_chars,
  89        .put_chars = hvc_beat_put_chars,
  90};
  91
  92static int hvc_beat_useit = 1;
  93
  94static int hvc_beat_config(char *p)
  95{
  96        hvc_beat_useit = simple_strtoul(p, NULL, 0);
  97        return 0;
  98}
  99
 100static int __init hvc_beat_console_init(void)
 101{
 102        if (hvc_beat_useit && machine_is_compatible("Beat")) {
 103                hvc_instantiate(0, 0, &hvc_beat_get_put_ops);
 104        }
 105        return 0;
 106}
 107
 108/* temp */
 109static int __init hvc_beat_init(void)
 110{
 111        struct hvc_struct *hp;
 112
 113        if (!firmware_has_feature(FW_FEATURE_BEAT))
 114                return -ENODEV;
 115
 116        hp = hvc_alloc(0, NO_IRQ, &hvc_beat_get_put_ops, 16);
 117        if (IS_ERR(hp))
 118                return PTR_ERR(hp);
 119        hvc_beat_dev = hp;
 120        return 0;
 121}
 122
 123static void __exit hvc_beat_exit(void)
 124{
 125        if (hvc_beat_dev)
 126                hvc_remove(hvc_beat_dev);
 127}
 128
 129module_init(hvc_beat_init);
 130module_exit(hvc_beat_exit);
 131
 132__setup("hvc_beat=", hvc_beat_config);
 133
 134console_initcall(hvc_beat_console_init);
 135