1 // SPDX-License-Identifier: GPL-2.0-or-later
2
3 /*
4 * IBM ASM Service Processor Device Driver
5 *
6 * Copyright (C) IBM Corporation, 2004
7 *
8 * Author: Max Asböck <amax@us.ibm.com>
9 */
10
11 #include <linux/sched.h>
12 #include <linux/slab.h>
13 #include "ibmasm.h"
14 #include "lowlevel.h"
15
16 static void exec_next_command(struct service_processor *sp);
17
18 static atomic_t command_count = ATOMIC_INIT(0);
19
ibmasm_new_command(struct service_processor * sp,size_t buffer_size)20 struct command *ibmasm_new_command(struct service_processor *sp, size_t buffer_size)
21 {
22 struct command *cmd;
23
24 if (buffer_size > IBMASM_CMD_MAX_BUFFER_SIZE)
25 return NULL;
26
27 cmd = kzalloc(sizeof(struct command), GFP_KERNEL);
28 if (cmd == NULL)
29 return NULL;
30
31
32 cmd->buffer = kzalloc(buffer_size, GFP_KERNEL);
33 if (cmd->buffer == NULL) {
34 kfree(cmd);
35 return NULL;
36 }
37 cmd->buffer_size = buffer_size;
38
39 kref_init(&cmd->kref);
40 cmd->lock = &sp->lock;
41
42 cmd->status = IBMASM_CMD_PENDING;
43 init_waitqueue_head(&cmd->wait);
44 INIT_LIST_HEAD(&cmd->queue_node);
45
46 atomic_inc(&command_count);
47 dbg("command count: %d\n", atomic_read(&command_count));
48
49 return cmd;
50 }
51
ibmasm_free_command(struct kref * kref)52 void ibmasm_free_command(struct kref *kref)
53 {
54 struct command *cmd = to_command(kref);
55
56 list_del(&cmd->queue_node);
57 atomic_dec(&command_count);
58 dbg("command count: %d\n", atomic_read(&command_count));
59 kfree(cmd->buffer);
60 kfree(cmd);
61 }
62
enqueue_command(struct service_processor * sp,struct command * cmd)63 static void enqueue_command(struct service_processor *sp, struct command *cmd)
64 {
65 list_add_tail(&cmd->queue_node, &sp->command_queue);
66 }
67
dequeue_command(struct service_processor * sp)68 static struct command *dequeue_command(struct service_processor *sp)
69 {
70 struct command *cmd;
71 struct list_head *next;
72
73 if (list_empty(&sp->command_queue))
74 return NULL;
75
76 next = sp->command_queue.next;
77 list_del_init(next);
78 cmd = list_entry(next, struct command, queue_node);
79
80 return cmd;
81 }
82
do_exec_command(struct service_processor * sp)83 static inline void do_exec_command(struct service_processor *sp)
84 {
85 char tsbuf[32];
86
87 dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
88
89 if (ibmasm_send_i2o_message(sp)) {
90 sp->current_command->status = IBMASM_CMD_FAILED;
91 wake_up(&sp->current_command->wait);
92 command_put(sp->current_command);
93 exec_next_command(sp);
94 }
95 }
96
97 /**
98 * exec_command
99 * send a command to a service processor
100 * Commands are executed sequentially. One command (sp->current_command)
101 * is sent to the service processor. Once the interrupt handler gets a
102 * message of type command_response, the message is copied into
103 * the current commands buffer,
104 */
ibmasm_exec_command(struct service_processor * sp,struct command * cmd)105 void ibmasm_exec_command(struct service_processor *sp, struct command *cmd)
106 {
107 unsigned long flags;
108 char tsbuf[32];
109
110 dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
111
112 spin_lock_irqsave(&sp->lock, flags);
113
114 if (!sp->current_command) {
115 sp->current_command = cmd;
116 command_get(sp->current_command);
117 spin_unlock_irqrestore(&sp->lock, flags);
118 do_exec_command(sp);
119 } else {
120 enqueue_command(sp, cmd);
121 spin_unlock_irqrestore(&sp->lock, flags);
122 }
123 }
124
exec_next_command(struct service_processor * sp)125 static void exec_next_command(struct service_processor *sp)
126 {
127 unsigned long flags;
128 char tsbuf[32];
129
130 dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
131
132 spin_lock_irqsave(&sp->lock, flags);
133 sp->current_command = dequeue_command(sp);
134 if (sp->current_command) {
135 command_get(sp->current_command);
136 spin_unlock_irqrestore(&sp->lock, flags);
137 do_exec_command(sp);
138 } else {
139 spin_unlock_irqrestore(&sp->lock, flags);
140 }
141 }
142
143 /**
144 * Sleep until a command has failed or a response has been received
145 * and the command status been updated by the interrupt handler.
146 * (see receive_response).
147 */
ibmasm_wait_for_response(struct command * cmd,int timeout)148 void ibmasm_wait_for_response(struct command *cmd, int timeout)
149 {
150 wait_event_interruptible_timeout(cmd->wait,
151 cmd->status == IBMASM_CMD_COMPLETE ||
152 cmd->status == IBMASM_CMD_FAILED,
153 timeout * HZ);
154 }
155
156 /**
157 * receive_command_response
158 * called by the interrupt handler when a dot command of type command_response
159 * was received.
160 */
ibmasm_receive_command_response(struct service_processor * sp,void * response,size_t size)161 void ibmasm_receive_command_response(struct service_processor *sp, void *response, size_t size)
162 {
163 struct command *cmd = sp->current_command;
164
165 if (!sp->current_command)
166 return;
167
168 memcpy_fromio(cmd->buffer, response, min(size, cmd->buffer_size));
169 cmd->status = IBMASM_CMD_COMPLETE;
170 wake_up(&sp->current_command->wait);
171 command_put(sp->current_command);
172 exec_next_command(sp);
173 }
174
