arch/ppc64/kernel/hvconsole.c

   1 /*
   2  * hvconsole.c
   3  * Copyright (C) 2004 Hollis Blanchard, IBM Corporation
   4  * Copyright (C) 2004 IBM Corporation
   5  *
   6  * Additional Author(s):
   7  *  Ryan S. Arnold <rsa@us.ibm.com>
   8  *
   9  * LPAR console support.
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  24  */
  25
  26 #include <linux/kernel.h>
  27 #include <linux/module.h>
  28 #include <asm/hvcall.h>
  29 #include <asm/hvconsole.h>
  30 #include <asm/prom.h>
  31
  32 /**
  33  * hvc_get_chars - retrieve characters from firmware for denoted vterm adatper
  34  * @vtermno: The vtermno or unit_address of the adapter from which to fetch the
  35  *      data.
  36  * @buf: The character buffer into which to put the character data fetched from
  37  *      firmware.
  38  * @count: not used?
  39  */
  40 int hvc_get_chars(uint32_t vtermno, char *buf, int count)
  41 {
  42         unsigned long got;
  43
  44         if (plpar_hcall(H_GET_TERM_CHAR, vtermno, 0, 0, 0, &got,
  45                 (unsigned long *)buf, (unsigned long *)buf+1) == H_Success) {
  46                 /*
  47                  * Work around a HV bug where it gives us a null
  48                  * after every \r.  -- paulus
  49                  */
  50                 if (got > 0) {
  51                         int i;
  52                         for (i = 1; i < got; ++i) {
  53                                 if (buf[i] == 0 && buf[i-1] == '\r') {
  54                                         --got;
  55                                         if (i < got)
  56                                                 memmove(&buf[i], &buf[i+1],
  57                                                         got - i);
  58                                 }
  59                         }
  60                 }
  61                 return got;
  62         }
  63         return 0;
  64 }
  65
  66 EXPORT_SYMBOL(hvc_get_chars);
  67
  68 /**
  69  * hvc_put_chars: send characters to firmware for denoted vterm adapter
  70  * @vtermno: The vtermno or unit_address of the adapter from which the data
  71  *      originated.
  72  * @buf: The character buffer that contains the character data to send to
  73  *      firmware.
  74  * @count: Send this number of characters.
  75  */
  76 int hvc_put_chars(uint32_t vtermno, const char *buf, int count)
  77 {
  78         unsigned long *lbuf = (unsigned long *) buf;
  79         long ret;
  80
  81         ret = plpar_hcall_norets(H_PUT_TERM_CHAR, vtermno, count, lbuf[0],
  82                                  lbuf[1]);
  83         if (ret == H_Success)
  84                 return count;
  85         if (ret == H_Busy)
  86                 return 0;
  87         return -EIO;
  88 }
  89
  90 EXPORT_SYMBOL(hvc_put_chars);
  91
  92 /*
  93  * We hope/assume that the first vty found corresponds to the first console
  94  * device.
  95  */
  96 int hvc_find_vtys(void)
  97 {
  98         struct device_node *vty;
  99         int num_found = 0;
 100
 101         for (vty = of_find_node_by_name(NULL, "vty"); vty != NULL;
 102                         vty = of_find_node_by_name(vty, "vty")) {
 103                 uint32_t *vtermno;
 104
 105                 /* We have statically defined space for only a certain number of
 106                  * console adapters. */
 107                 if (num_found >= MAX_NR_HVC_CONSOLES)
 108                         break;
 109
 110                 vtermno = (uint32_t *)get_property(vty, "reg", NULL);
 111                 if (!vtermno)
 112                         continue;
 113
 114                 if (device_is_compatible(vty, "hvterm1")) {
 115                         hvc_instantiate(*vtermno, num_found);
 116                         ++num_found;
 117                 }
 118         }
 119
 120         return num_found;
 121 }