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
16static void exec_next_command(struct service_processor *sp);
17
18static atomic_t command_count = ATOMIC_INIT(0);
19
20struct 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(size: sizeof(struct command), GFP_KERNEL);
28 if (cmd == NULL)
29 return NULL;
30
31
32 cmd->buffer = kzalloc(size: buffer_size, GFP_KERNEL);
33 if (cmd->buffer == NULL) {
34 kfree(objp: cmd);
35 return NULL;
36 }
37 cmd->buffer_size = buffer_size;
38
39 kref_init(kref: &cmd->kref);
40 cmd->lock = &sp->lock;
41
42 cmd->status = IBMASM_CMD_PENDING;
43 init_waitqueue_head(&cmd->wait);
44 INIT_LIST_HEAD(list: &cmd->queue_node);
45
46 atomic_inc(v: &command_count);
47 dbg("command count: %d\n", atomic_read(&command_count));
48
49 return cmd;
50}
51
52void ibmasm_free_command(struct kref *kref)
53{
54 struct command *cmd = to_command(kref);
55
56 list_del(entry: &cmd->queue_node);
57 atomic_dec(v: &command_count);
58 dbg("command count: %d\n", atomic_read(&command_count));
59 kfree(objp: cmd->buffer);
60 kfree(objp: cmd);
61}
62
63static void enqueue_command(struct service_processor *sp, struct command *cmd)
64{
65 list_add_tail(new: &cmd->queue_node, head: &sp->command_queue);
66}
67
68static struct command *dequeue_command(struct service_processor *sp)
69{
70 struct command *cmd;
71 struct list_head *next;
72
73 if (list_empty(head: &sp->command_queue))
74 return NULL;
75
76 next = sp->command_queue.next;
77 list_del_init(entry: next);
78 cmd = list_entry(next, struct command, queue_node);
79
80 return cmd;
81}
82
83static 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(cmd: 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 */
105void 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(cmd: sp->current_command);
117 spin_unlock_irqrestore(lock: &sp->lock, flags);
118 do_exec_command(sp);
119 } else {
120 enqueue_command(sp, cmd);
121 spin_unlock_irqrestore(lock: &sp->lock, flags);
122 }
123}
124
125static 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(cmd: sp->current_command);
136 spin_unlock_irqrestore(lock: &sp->lock, flags);
137 do_exec_command(sp);
138 } else {
139 spin_unlock_irqrestore(lock: &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 */
148void 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 */
161void 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(cmd: sp->current_command);
172 exec_next_command(sp);
173}
174

source code of linux/drivers/misc/ibmasm/command.c