LXR linux/arch/powerpc/platforms/pseries/hvcserver.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * hvcserver.c
   4 * Copyright (C) 2004 Ryan S Arnold, IBM Corporation
   5 *
   6 * PPC64 virtual I/O console server support.
   7 */
   8
   9#include <linux/kernel.h>
  10#include <linux/list.h>
  11#include <linux/module.h>
  12#include <linux/slab.h>
  13#include <linux/string.h>
  14
  15#include <asm/hvcall.h>
  16#include <asm/hvcserver.h>
  17#include <asm/io.h>
  18
  19#define HVCS_ARCH_VERSION "1.0.0"
  20
  21MODULE_AUTHOR("Ryan S. Arnold <rsa@us.ibm.com>");
  22MODULE_DESCRIPTION("IBM hvcs ppc64 API");
  23MODULE_LICENSE("GPL");
  24MODULE_VERSION(HVCS_ARCH_VERSION);
  25
  26/*
  27 * Convert arch specific return codes into relevant errnos.  The hvcs
  28 * functions aren't performance sensitive, so this conversion isn't an
  29 * issue.
  30 */
  31static int hvcs_convert(long to_convert)
  32{
  33        switch (to_convert) {
  34                case H_SUCCESS:
  35                        return 0;
  36                case H_PARAMETER:
  37                        return -EINVAL;
  38                case H_HARDWARE:
  39                        return -EIO;
  40                case H_BUSY:
  41                case H_LONG_BUSY_ORDER_1_MSEC:
  42                case H_LONG_BUSY_ORDER_10_MSEC:
  43                case H_LONG_BUSY_ORDER_100_MSEC:
  44                case H_LONG_BUSY_ORDER_1_SEC:
  45                case H_LONG_BUSY_ORDER_10_SEC:
  46                case H_LONG_BUSY_ORDER_100_SEC:
  47                        return -EBUSY;
  48                case H_FUNCTION:
  49                default:
  50                        return -EPERM;
  51        }
  52}
  53
  54/**
  55 * hvcs_free_partner_info - free pi allocated by hvcs_get_partner_info
  56 * @head: list_head pointer for an allocated list of partner info structs to
  57 *      free.
  58 *
  59 * This function is used to free the partner info list that was returned by
  60 * calling hvcs_get_partner_info().
  61 */
  62int hvcs_free_partner_info(struct list_head *head)
  63{
  64        struct hvcs_partner_info *pi;
  65        struct list_head *element;
  66
  67        if (!head)
  68                return -EINVAL;
  69
  70        while (!list_empty(head)) {
  71                element = head->next;
  72                pi = list_entry(element, struct hvcs_partner_info, node);
  73                list_del(element);
  74                kfree(pi);
  75        }
  76
  77        return 0;
  78}
  79EXPORT_SYMBOL(hvcs_free_partner_info);
  80
  81/* Helper function for hvcs_get_partner_info */
  82static int hvcs_next_partner(uint32_t unit_address,
  83                unsigned long last_p_partition_ID,
  84                unsigned long last_p_unit_address, unsigned long *pi_buff)
  85
  86{
  87        long retval;
  88        retval = plpar_hcall_norets(H_VTERM_PARTNER_INFO, unit_address,
  89                        last_p_partition_ID,
  90                                last_p_unit_address, virt_to_phys(pi_buff));
  91        return hvcs_convert(retval);
  92}
  93
  94/**
  95 * hvcs_get_partner_info - Get all of the partner info for a vty-server adapter
  96 * @unit_address: The unit_address of the vty-server adapter for which this
  97 *      function is fetching partner info.
  98 * @head: An initialized list_head pointer to an empty list to use to return the
  99 *      list of partner info fetched from the hypervisor to the caller.
 100 * @pi_buff: A page sized buffer pre-allocated prior to calling this function
 101 *      that is to be used to be used by firmware as an iterator to keep track
 102 *      of the partner info retrieval.
 103 *
 104 * This function returns non-zero on success, or if there is no partner info.
 105 *
 106 * The pi_buff is pre-allocated prior to calling this function because this
 107 * function may be called with a spin_lock held and kmalloc of a page is not
 108 * recommended as GFP_ATOMIC.
 109 *
 110 * The first long of this buffer is used to store a partner unit address.  The
 111 * second long is used to store a partner partition ID and starting at
 112 * pi_buff[2] is the 79 character Converged Location Code (diff size than the
 113 * unsigned longs, hence the casting mumbo jumbo you see later).
 114 *
 115 * Invocation of this function should always be followed by an invocation of
 116 * hvcs_free_partner_info() using a pointer to the SAME list head instance
 117 * that was passed as a parameter to this function.
 118 */
 119int hvcs_get_partner_info(uint32_t unit_address, struct list_head *head,
 120                unsigned long *pi_buff)
 121{
 122        /*
 123         * Dealt with as longs because of the hcall interface even though the
 124         * values are uint32_t.
 125         */
 126        unsigned long   last_p_partition_ID;
 127        unsigned long   last_p_unit_address;
 128        struct hvcs_partner_info *next_partner_info = NULL;
 129        int more = 1;
 130        int retval;
 131
 132        /* invalid parameters */
 133        if (!head || !pi_buff)
 134                return -EINVAL;
 135
 136        memset(pi_buff, 0x00, PAGE_SIZE);
 137        last_p_partition_ID = last_p_unit_address = ~0UL;
 138        INIT_LIST_HEAD(head);
 139
 140        do {
 141                retval = hvcs_next_partner(unit_address, last_p_partition_ID,
 142                                last_p_unit_address, pi_buff);
 143                if (retval) {
 144                        /*
 145                         * Don't indicate that we've failed if we have
 146                         * any list elements.
 147                         */
 148                        if (!list_empty(head))
 149                                return 0;
 150                        return retval;
 151                }
 152
 153                last_p_partition_ID = be64_to_cpu(pi_buff[0]);
 154                last_p_unit_address = be64_to_cpu(pi_buff[1]);
 155
 156                /* This indicates that there are no further partners */
 157                if (last_p_partition_ID == ~0UL
 158                                && last_p_unit_address == ~0UL)
 159                        break;
 160
 161                /* This is a very small struct and will be freed soon in
 162                 * hvcs_free_partner_info(). */
 163                next_partner_info = kmalloc(sizeof(struct hvcs_partner_info),
 164                                GFP_ATOMIC);
 165
 166                if (!next_partner_info) {
 167                        printk(KERN_WARNING "HVCONSOLE: kmalloc() failed to"
 168                                " allocate partner info struct.\n");
 169                        hvcs_free_partner_info(head);
 170                        return -ENOMEM;
 171                }
 172
 173                next_partner_info->unit_address
 174                        = (unsigned int)last_p_unit_address;
 175                next_partner_info->partition_ID
 176                        = (unsigned int)last_p_partition_ID;
 177
 178                /* copy the Null-term char too */
 179                strlcpy(&next_partner_info->location_code[0],
 180                        (char *)&pi_buff[2],
 181                        sizeof(next_partner_info->location_code));
 182
 183                list_add_tail(&(next_partner_info->node), head);
 184                next_partner_info = NULL;
 185
 186        } while (more);
 187
 188        return 0;
 189}
 190EXPORT_SYMBOL(hvcs_get_partner_info);
 191
 192/**
 193 * hvcs_register_connection - establish a connection between this vty-server and
 194 *      a vty.
 195 * @unit_address: The unit address of the vty-server adapter that is to be
 196 *      establish a connection.
 197 * @p_partition_ID: The partition ID of the vty adapter that is to be connected.
 198 * @p_unit_address: The unit address of the vty adapter to which the vty-server
 199 *      is to be connected.
 200 *
 201 * If this function is called once and -EINVAL is returned it may
 202 * indicate that the partner info needs to be refreshed for the
 203 * target unit address at which point the caller must invoke
 204 * hvcs_get_partner_info() and then call this function again.  If,
 205 * for a second time, -EINVAL is returned then it indicates that
 206 * there is probably already a partner connection registered to a
 207 * different vty-server adapter.  It is also possible that a second
 208 * -EINVAL may indicate that one of the parms is not valid, for
 209 * instance if the link was removed between the vty-server adapter
 210 * and the vty adapter that you are trying to open.  Don't shoot the
 211 * messenger.  Firmware implemented it this way.
 212 */
 213int hvcs_register_connection( uint32_t unit_address,
 214                uint32_t p_partition_ID, uint32_t p_unit_address)
 215{
 216        long retval;
 217        retval = plpar_hcall_norets(H_REGISTER_VTERM, unit_address,
 218                                p_partition_ID, p_unit_address);
 219        return hvcs_convert(retval);
 220}
 221EXPORT_SYMBOL(hvcs_register_connection);
 222
 223/**
 224 * hvcs_free_connection - free the connection between a vty-server and vty
 225 * @unit_address: The unit address of the vty-server that is to have its
 226 *      connection severed.
 227 *
 228 * This function is used to free the partner connection between a vty-server
 229 * adapter and a vty adapter.
 230 *
 231 * If -EBUSY is returned continue to call this function until 0 is returned.
 232 */
 233int hvcs_free_connection(uint32_t unit_address)
 234{
 235        long retval;
 236        retval = plpar_hcall_norets(H_FREE_VTERM, unit_address);
 237        return hvcs_convert(retval);
 238}
 239EXPORT_SYMBOL(hvcs_free_connection);
 240