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1/*
2 * OPAL Operator Panel Display Driver
3 *
4 * Copyright 2016, Suraj Jitindar Singh, IBM Corporation.
5 */
6
7#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8
9#include <linux/init.h>
10#include <linux/module.h>
11#include <linux/kernel.h>
12#include <linux/fs.h>
13#include <linux/device.h>
14#include <linux/errno.h>
15#include <linux/mutex.h>
16#include <linux/of.h>
17#include <linux/slab.h>
18#include <linux/platform_device.h>
19#include <linux/miscdevice.h>
20
21#include <asm/opal.h>
22
23/*
24 * This driver creates a character device (/dev/op_panel) which exposes the
25 * operator panel (character LCD display) on IBM Power Systems machines
26 * with FSPs.
27 * A character buffer written to the device will be displayed on the
28 * operator panel.
29 */
30
31static DEFINE_MUTEX(oppanel_mutex);
32
33static u32 num_lines, oppanel_size;
34static oppanel_line_t *oppanel_lines;
35static char *oppanel_data;
36
37static loff_t oppanel_llseek(struct file *filp, loff_t offset, int whence)
38{
39 return fixed_size_llseek(filp, offset, whence, oppanel_size);
40}
41
42static ssize_t oppanel_read(struct file *filp, char __user *userbuf, size_t len,
43 loff_t *f_pos)
44{
45 return simple_read_from_buffer(userbuf, len, f_pos, oppanel_data,
46 oppanel_size);
47}
48
49static int __op_panel_update_display(void)
50{
51 struct opal_msg msg;
52 int rc, token;
53
54 token = opal_async_get_token_interruptible();
55 if (token < 0) {
56 if (token != -ERESTARTSYS)
57 pr_debug("Couldn't get OPAL async token [token=%d]\n",
58 token);
59 return token;
60 }
61
62 rc = opal_write_oppanel_async(token, oppanel_lines, num_lines);
63 switch (rc) {
64 case OPAL_ASYNC_COMPLETION:
65 rc = opal_async_wait_response(token, &msg);
66 if (rc) {
67 pr_debug("Failed to wait for async response [rc=%d]\n",
68 rc);
69 break;
70 }
71 rc = opal_get_async_rc(msg);
72 if (rc != OPAL_SUCCESS) {
73 pr_debug("OPAL async call returned failed [rc=%d]\n",
74 rc);
75 break;
76 }
77 case OPAL_SUCCESS:
78 break;
79 default:
80 pr_debug("OPAL write op-panel call failed [rc=%d]\n", rc);
81 }
82
83 opal_async_release_token(token);
84 return rc;
85}
86
87static ssize_t oppanel_write(struct file *filp, const char __user *userbuf,
88 size_t len, loff_t *f_pos)
89{
90 loff_t f_pos_prev = *f_pos;
91 ssize_t ret;
92 int rc;
93
94 if (!*f_pos)
95 memset(oppanel_data, ' ', oppanel_size);
96 else if (*f_pos >= oppanel_size)
97 return -EFBIG;
98
99 ret = simple_write_to_buffer(oppanel_data, oppanel_size, f_pos, userbuf,
100 len);
101 if (ret > 0) {
102 rc = __op_panel_update_display();
103 if (rc != OPAL_SUCCESS) {
104 pr_err_ratelimited("OPAL call failed to write to op panel display [rc=%d]\n",
105 rc);
106 *f_pos = f_pos_prev;
107 return -EIO;
108 }
109 }
110 return ret;
111}
112
113static int oppanel_open(struct inode *inode, struct file *filp)
114{
115 if (!mutex_trylock(&oppanel_mutex)) {
116 pr_debug("Device Busy\n");
117 return -EBUSY;
118 }
119 return 0;
120}
121
122static int oppanel_release(struct inode *inode, struct file *filp)
123{
124 mutex_unlock(&oppanel_mutex);
125 return 0;
126}
127
128static const struct file_operations oppanel_fops = {
129 .owner = THIS_MODULE,
130 .llseek = oppanel_llseek,
131 .read = oppanel_read,
132 .write = oppanel_write,
133 .open = oppanel_open,
134 .release = oppanel_release
135};
136
137static struct miscdevice oppanel_dev = {
138 .minor = MISC_DYNAMIC_MINOR,
139 .name = "op_panel",
140 .fops = &oppanel_fops
141};
142
143static int oppanel_probe(struct platform_device *pdev)
144{
145 struct device_node *np = pdev->dev.of_node;
146 u32 line_len;
147 int rc, i;
148
149 rc = of_property_read_u32(np, "#length", &line_len);
150 if (rc) {
151 pr_err_ratelimited("Operator panel length property not found\n");
152 return rc;
153 }
154 rc = of_property_read_u32(np, "#lines", &num_lines);
155 if (rc) {
156 pr_err_ratelimited("Operator panel lines property not found\n");
157 return rc;
158 }
159 oppanel_size = line_len * num_lines;
160
161 pr_devel("Operator panel of size %u found with %u lines of length %u\n",
162 oppanel_size, num_lines, line_len);
163
164 oppanel_data = kcalloc(oppanel_size, sizeof(*oppanel_data), GFP_KERNEL);
165 if (!oppanel_data)
166 return -ENOMEM;
167
168 oppanel_lines = kcalloc(num_lines, sizeof(oppanel_line_t), GFP_KERNEL);
169 if (!oppanel_lines) {
170 rc = -ENOMEM;
171 goto free_oppanel_data;
172 }
173
174 memset(oppanel_data, ' ', oppanel_size);
175 for (i = 0; i < num_lines; i++) {
176 oppanel_lines[i].line_len = cpu_to_be64(line_len);
177 oppanel_lines[i].line = cpu_to_be64(__pa(&oppanel_data[i *
178 line_len]));
179 }
180
181 rc = misc_register(&oppanel_dev);
182 if (rc) {
183 pr_err_ratelimited("Failed to register as misc device\n");
184 goto free_oppanel;
185 }
186
187 return 0;
188
189free_oppanel:
190 kfree(oppanel_lines);
191free_oppanel_data:
192 kfree(oppanel_data);
193 return rc;
194}
195
196static int oppanel_remove(struct platform_device *pdev)
197{
198 misc_deregister(&oppanel_dev);
199 kfree(oppanel_lines);
200 kfree(oppanel_data);
201 return 0;
202}
203
204static const struct of_device_id oppanel_match[] = {
205 { .compatible = "ibm,opal-oppanel" },
206 { },
207};
208
209static struct platform_driver oppanel_driver = {
210 .driver = {
211 .name = "powernv-op-panel",
212 .of_match_table = oppanel_match,
213 },
214 .probe = oppanel_probe,
215 .remove = oppanel_remove,
216};
217
218module_platform_driver(oppanel_driver);
219
220MODULE_DEVICE_TABLE(of, oppanel_match);
221MODULE_LICENSE("GPL v2");
222MODULE_DESCRIPTION("PowerNV Operator Panel LCD Display Driver");
223MODULE_AUTHOR("Suraj Jitindar Singh <sjitindarsingh@gmail.com>");
224

Warning: That file was not part of the compilation database. It may have many parsing errors.