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:
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 strscpy(&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);
240
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