1/*
2 * hvcserver.c
3 * Copyright (C) 2004 Ryan S Arnold, IBM Corporation
4 *
5 * PPC64 virtual I/O console server support.
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
20 */
21
22#include <linux/kernel.h>
23#include <linux/list.h>
24#include <linux/module.h>
25#include <linux/slab.h>
26#include <linux/string.h>
27
28#include <asm/hvcall.h>
29#include <asm/hvcserver.h>
30#include <asm/io.h>
31
32#define HVCS_ARCH_VERSION "1.0.0"
33
34MODULE_AUTHOR("Ryan S. Arnold <rsa@us.ibm.com>");
35MODULE_DESCRIPTION("IBM hvcs ppc64 API");
36MODULE_LICENSE("GPL");
37MODULE_VERSION(HVCS_ARCH_VERSION);
38
39/*
40 * Convert arch specific return codes into relevant errnos.  The hvcs
41 * functions aren't performance sensitive, so this conversion isn't an
42 * issue.
43 */
44static int hvcs_convert(long to_convert)
45{
46	switch (to_convert) {
47		case H_SUCCESS:
48			return 0;
49		case H_PARAMETER:
50			return -EINVAL;
51		case H_HARDWARE:
52			return -EIO;
53		case H_BUSY:
54		case H_LONG_BUSY_ORDER_1_MSEC:
55		case H_LONG_BUSY_ORDER_10_MSEC:
56		case H_LONG_BUSY_ORDER_100_MSEC:
57		case H_LONG_BUSY_ORDER_1_SEC:
58		case H_LONG_BUSY_ORDER_10_SEC:
59		case H_LONG_BUSY_ORDER_100_SEC:
60			return -EBUSY;
61		case H_FUNCTION: /* fall through */
62		default:
63			return -EPERM;
64	}
65}
66
67/**
68 * hvcs_free_partner_info - free pi allocated by hvcs_get_partner_info
69 * @head: list_head pointer for an allocated list of partner info structs to
70 *	free.
71 *
72 * This function is used to free the partner info list that was returned by
73 * calling hvcs_get_partner_info().
74 */
75int hvcs_free_partner_info(struct list_head *head)
76{
77	struct hvcs_partner_info *pi;
78	struct list_head *element;
79
80	if (!head)
81		return -EINVAL;
82
83	while (!list_empty(head)) {
84		element = head->next;
85		pi = list_entry(element, struct hvcs_partner_info, node);
86		list_del(element);
87		kfree(pi);
88	}
89
90	return 0;
91}
92EXPORT_SYMBOL(hvcs_free_partner_info);
93
94/* Helper function for hvcs_get_partner_info */
95static int hvcs_next_partner(uint32_t unit_address,
96		unsigned long last_p_partition_ID,
97		unsigned long last_p_unit_address, unsigned long *pi_buff)
98
99{
100	long retval;
101	retval = plpar_hcall_norets(H_VTERM_PARTNER_INFO, unit_address,
102			last_p_partition_ID,
103				last_p_unit_address, virt_to_phys(pi_buff));
104	return hvcs_convert(retval);
105}
106
107/**
108 * hvcs_get_partner_info - Get all of the partner info for a vty-server adapter
109 * @unit_address: The unit_address of the vty-server adapter for which this
110 *	function is fetching partner info.
111 * @head: An initialized list_head pointer to an empty list to use to return the
112 *	list of partner info fetched from the hypervisor to the caller.
113 * @pi_buff: A page sized buffer pre-allocated prior to calling this function
114 *	that is to be used to be used by firmware as an iterator to keep track
115 *	of the partner info retrieval.
116 *
117 * This function returns non-zero on success, or if there is no partner info.
118 *
119 * The pi_buff is pre-allocated prior to calling this function because this
120 * function may be called with a spin_lock held and kmalloc of a page is not
121 * recommended as GFP_ATOMIC.
122 *
123 * The first long of this buffer is used to store a partner unit address.  The
124 * second long is used to store a partner partition ID and starting at
125 * pi_buff[2] is the 79 character Converged Location Code (diff size than the
126 * unsigned longs, hence the casting mumbo jumbo you see later).
127 *
128 * Invocation of this function should always be followed by an invocation of
129 * hvcs_free_partner_info() using a pointer to the SAME list head instance
130 * that was passed as a parameter to this function.
131 */
132int hvcs_get_partner_info(uint32_t unit_address, struct list_head *head,
133		unsigned long *pi_buff)
134{
135	/*
136	 * Dealt with as longs because of the hcall interface even though the
137	 * values are uint32_t.
138	 */
139	unsigned long	last_p_partition_ID;
140	unsigned long	last_p_unit_address;
141	struct hvcs_partner_info *next_partner_info = NULL;
142	int more = 1;
143	int retval;
144
145	memset(pi_buff, 0x00, PAGE_SIZE);
146	/* invalid parameters */
147	if (!head || !pi_buff)
148		return -EINVAL;
149
150	last_p_partition_ID = last_p_unit_address = ~0UL;
151	INIT_LIST_HEAD(head);
152
153	do {
154		retval = hvcs_next_partner(unit_address, last_p_partition_ID,
155				last_p_unit_address, pi_buff);
156		if (retval) {
157			/*
158			 * Don't indicate that we've failed if we have
159			 * any list elements.
160			 */
161			if (!list_empty(head))
162				return 0;
163			return retval;
164		}
165
166		last_p_partition_ID = be64_to_cpu(pi_buff[0]);
167		last_p_unit_address = be64_to_cpu(pi_buff[1]);
168
169		/* This indicates that there are no further partners */
170		if (last_p_partition_ID == ~0UL
171				&& last_p_unit_address == ~0UL)
172			break;
173
174		/* This is a very small struct and will be freed soon in
175		 * hvcs_free_partner_info(). */
176		next_partner_info = kmalloc(sizeof(struct hvcs_partner_info),
177				GFP_ATOMIC);
178
179		if (!next_partner_info) {
180			printk(KERN_WARNING "HVCONSOLE: kmalloc() failed to"
181				" allocate partner info struct.\n");
182			hvcs_free_partner_info(head);
183			return -ENOMEM;
184		}
185
186		next_partner_info->unit_address
187			= (unsigned int)last_p_unit_address;
188		next_partner_info->partition_ID
189			= (unsigned int)last_p_partition_ID;
190
191		/* copy the Null-term char too */
192		strlcpy(&next_partner_info->location_code[0],
193			(char *)&pi_buff[2],
194			sizeof(next_partner_info->location_code));
195
196		list_add_tail(&(next_partner_info->node), head);
197		next_partner_info = NULL;
198
199	} while (more);
200
201	return 0;
202}
203EXPORT_SYMBOL(hvcs_get_partner_info);
204
205/**
206 * hvcs_register_connection - establish a connection between this vty-server and
207 *	a vty.
208 * @unit_address: The unit address of the vty-server adapter that is to be
209 *	establish a connection.
210 * @p_partition_ID: The partition ID of the vty adapter that is to be connected.
211 * @p_unit_address: The unit address of the vty adapter to which the vty-server
212 *	is to be connected.
213 *
214 * If this function is called once and -EINVAL is returned it may
215 * indicate that the partner info needs to be refreshed for the
216 * target unit address at which point the caller must invoke
217 * hvcs_get_partner_info() and then call this function again.  If,
218 * for a second time, -EINVAL is returned then it indicates that
219 * there is probably already a partner connection registered to a
220 * different vty-server adapter.  It is also possible that a second
221 * -EINVAL may indicate that one of the parms is not valid, for
222 * instance if the link was removed between the vty-server adapter
223 * and the vty adapter that you are trying to open.  Don't shoot the
224 * messenger.  Firmware implemented it this way.
225 */
226int hvcs_register_connection( uint32_t unit_address,
227		uint32_t p_partition_ID, uint32_t p_unit_address)
228{
229	long retval;
230	retval = plpar_hcall_norets(H_REGISTER_VTERM, unit_address,
231				p_partition_ID, p_unit_address);
232	return hvcs_convert(retval);
233}
234EXPORT_SYMBOL(hvcs_register_connection);
235
236/**
237 * hvcs_free_connection - free the connection between a vty-server and vty
238 * @unit_address: The unit address of the vty-server that is to have its
239 *	connection severed.
240 *
241 * This function is used to free the partner connection between a vty-server
242 * adapter and a vty adapter.
243 *
244 * If -EBUSY is returned continue to call this function until 0 is returned.
245 */
246int hvcs_free_connection(uint32_t unit_address)
247{
248	long retval;
249	retval = plpar_hcall_norets(H_FREE_VTERM, unit_address);
250	return hvcs_convert(retval);
251}
252EXPORT_SYMBOL(hvcs_free_connection);
253