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  */
hvcs_convert(long to_convert)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  */
hvcs_free_partner_info(struct list_head * head)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 */
hvcs_next_partner(uint32_t unit_address,unsigned long last_p_partition_ID,unsigned long last_p_unit_address,unsigned long * pi_buff)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  */
hvcs_get_partner_info(uint32_t unit_address,struct list_head * head,unsigned long * pi_buff)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  */
hvcs_register_connection(uint32_t unit_address,uint32_t p_partition_ID,uint32_t p_unit_address)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  */
hvcs_free_connection(uint32_t unit_address)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