drivers/char/hvc_vio.c

   1 /*
   2  * vio driver interface to hvc_console.c
   3  *
   4  * This code was moved here to allow the remaing code to be reused as a
   5  * generic polling mode with semi-reliable transport driver core to the
   6  * console and tty subsystems.
   7  *
   8  *
   9  * Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
  10  * Copyright (C) 2001 Paul Mackerras <paulus@au.ibm.com>, IBM
  11  * Copyright (C) 2004 Benjamin Herrenschmidt <benh@kernel.crashing.org>, IBM Corp.
  12  * Copyright (C) 2004 IBM Corporation
  13  *
  14  * Additional Author(s):
  15  *  Ryan S. Arnold <rsa@us.ibm.com>
  16  *
  17  * This program is free software; you can redistribute it and/or modify
  18  * it under the terms of the GNU General Public License as published by
  19  * the Free Software Foundation; either version 2 of the License, or
  20  * (at your option) any later version.
  21  *
  22  * This program is distributed in the hope that it will be useful,
  23  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  24  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  25  * GNU General Public License for more details.
  26  *
  27  * You should have received a copy of the GNU General Public License
  28  * along with this program; if not, write to the Free Software
  29  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  30  */
  31
  32 #include <linux/types.h>
  33 #include <linux/init.h>
  34
  35 #include <asm/hvconsole.h>
  36 #include <asm/vio.h>
  37 #include <asm/prom.h>
  38 #include <asm/firmware.h>
  39
  40 #include "hvc_console.h"
  41
  42 char hvc_driver_name[] = "hvc_console";
  43
  44 static struct vio_device_id hvc_driver_table[] __devinitdata = {
  45         {"serial", "hvterm1"},
  46         { "", "" }
  47 };
  48 MODULE_DEVICE_TABLE(vio, hvc_driver_table);
  49
  50 static int filtered_get_chars(uint32_t vtermno, char *buf, int count)
  51 {
  52         unsigned long got;
  53         int i;
  54
  55         /*
  56          * Vio firmware will read up to SIZE_VIO_GET_CHARS at its own discretion
  57          * so we play safe and avoid the situation where got > count which could
  58          * overload the flip buffer.
  59          */
  60         if (count < SIZE_VIO_GET_CHARS)
  61                 return -EAGAIN;
  62
  63         got = hvc_get_chars(vtermno, buf, count);
  64
  65         /*
  66          * Work around a HV bug where it gives us a null
  67          * after every \r.  -- paulus
  68          */
  69         for (i = 1; i < got; ++i) {
  70                 if (buf[i] == 0 && buf[i-1] == '\r') {
  71                         --got;
  72                         if (i < got)
  73                                 memmove(&buf[i], &buf[i+1],
  74                                         got - i);
  75                 }
  76         }
  77         return got;
  78 }
  79
  80 static struct hv_ops hvc_get_put_ops = {
  81         .get_chars = filtered_get_chars,
  82         .put_chars = hvc_put_chars,
  83 };
  84
  85 static int __devinit hvc_vio_probe(struct vio_dev *vdev,
  86                                 const struct vio_device_id *id)
  87 {
  88         struct hvc_struct *hp;
  89
  90         /* probed with invalid parameters. */
  91         if (!vdev || !id)
  92                 return -EPERM;
  93
  94         hp = hvc_alloc(vdev->unit_address, vdev->irq, &hvc_get_put_ops,
  95                         MAX_VIO_PUT_CHARS);
  96         if (IS_ERR(hp))
  97                 return PTR_ERR(hp);
  98         dev_set_drvdata(&vdev->dev, hp);
  99
 100         return 0;
 101 }
 102
 103 static int __devexit hvc_vio_remove(struct vio_dev *vdev)
 104 {
 105         struct hvc_struct *hp = dev_get_drvdata(&vdev->dev);
 106
 107         return hvc_remove(hp);
 108 }
 109
 110 static struct vio_driver hvc_vio_driver = {
 111         .id_table       = hvc_driver_table,
 112         .probe          = hvc_vio_probe,
 113         .remove         = hvc_vio_remove,
 114         .driver         = {
 115                 .name   = hvc_driver_name,
 116                 .owner  = THIS_MODULE,
 117         }
 118 };
 119
 120 static int hvc_vio_init(void)
 121 {
 122         int rc;
 123
 124         if (firmware_has_feature(FW_FEATURE_ISERIES))
 125                 return -EIO;
 126
 127         /* Register as a vio device to receive callbacks */
 128         rc = vio_register_driver(&hvc_vio_driver);
 129
 130         return rc;
 131 }
 132 module_init(hvc_vio_init); /* after drivers/char/hvc_console.c */
 133
 134 static void hvc_vio_exit(void)
 135 {
 136         vio_unregister_driver(&hvc_vio_driver);
 137 }
 138 module_exit(hvc_vio_exit);
 139
 140 /* the device tree order defines our numbering */
 141 static int hvc_find_vtys(void)
 142 {
 143         struct device_node *vty;
 144         int num_found = 0;
 145
 146         for (vty = of_find_node_by_name(NULL, "vty"); vty != NULL;
 147                         vty = of_find_node_by_name(vty, "vty")) {
 148                 const uint32_t *vtermno;
 149
 150                 /* We have statically defined space for only a certain number
 151                  * of console adapters.
 152                  */
 153                 if (num_found >= MAX_NR_HVC_CONSOLES)
 154                         break;
 155
 156                 vtermno = of_get_property(vty, "reg", NULL);
 157                 if (!vtermno)
 158                         continue;
 159
 160                 if (of_device_is_compatible(vty, "hvterm1")) {
 161                         hvc_instantiate(*vtermno, num_found, &hvc_get_put_ops);
 162                         ++num_found;
 163                 }
 164         }
 165
 166         return num_found;
 167 }
 168 console_initcall(hvc_find_vtys);