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		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}
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