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
  21 MODULE_AUTHOR("Ryan S. Arnold <rsa@us.ibm.com>");
  22 MODULE_DESCRIPTION("IBM hvcs ppc64 API");
  23 MODULE_LICENSE("GPL");
  24 MODULE_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  */
  31 static 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: /* fall through */
  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  */
  62 int 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 }
  79 EXPORT_SYMBOL(hvcs_free_partner_info);
  80
  81 /* Helper function for hvcs_get_partner_info */
  82 static 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  */
 119 int 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 }
 190 EXPORT_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  */
 213 int 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 }
 221 EXPORT_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  */
 233 int 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 }
 239 EXPORT_SYMBOL(hvcs_free_connection);