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09c434b8 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
43a1dd9b SJS |
2 | /* |
3 | * OPAL Operator Panel Display Driver | |
4 | * | |
5 | * Copyright 2016, Suraj Jitindar Singh, IBM Corporation. | |
6 | */ | |
7 | ||
8 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
9 | ||
10 | #include <linux/init.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/kernel.h> | |
13 | #include <linux/fs.h> | |
14 | #include <linux/device.h> | |
15 | #include <linux/errno.h> | |
16 | #include <linux/mutex.h> | |
17 | #include <linux/of.h> | |
18 | #include <linux/slab.h> | |
19 | #include <linux/platform_device.h> | |
20 | #include <linux/miscdevice.h> | |
21 | ||
22 | #include <asm/opal.h> | |
23 | ||
24 | /* | |
25 | * This driver creates a character device (/dev/op_panel) which exposes the | |
26 | * operator panel (character LCD display) on IBM Power Systems machines | |
27 | * with FSPs. | |
28 | * A character buffer written to the device will be displayed on the | |
29 | * operator panel. | |
30 | */ | |
31 | ||
32 | static DEFINE_MUTEX(oppanel_mutex); | |
33 | ||
34 | static u32 num_lines, oppanel_size; | |
35 | static oppanel_line_t *oppanel_lines; | |
36 | static char *oppanel_data; | |
37 | ||
38 | static loff_t oppanel_llseek(struct file *filp, loff_t offset, int whence) | |
39 | { | |
40 | return fixed_size_llseek(filp, offset, whence, oppanel_size); | |
41 | } | |
42 | ||
43 | static ssize_t oppanel_read(struct file *filp, char __user *userbuf, size_t len, | |
44 | loff_t *f_pos) | |
45 | { | |
46 | return simple_read_from_buffer(userbuf, len, f_pos, oppanel_data, | |
47 | oppanel_size); | |
48 | } | |
49 | ||
50 | static int __op_panel_update_display(void) | |
51 | { | |
52 | struct opal_msg msg; | |
53 | int rc, token; | |
54 | ||
55 | token = opal_async_get_token_interruptible(); | |
56 | if (token < 0) { | |
57 | if (token != -ERESTARTSYS) | |
58 | pr_debug("Couldn't get OPAL async token [token=%d]\n", | |
59 | token); | |
60 | return token; | |
61 | } | |
62 | ||
63 | rc = opal_write_oppanel_async(token, oppanel_lines, num_lines); | |
64 | switch (rc) { | |
65 | case OPAL_ASYNC_COMPLETION: | |
66 | rc = opal_async_wait_response(token, &msg); | |
67 | if (rc) { | |
68 | pr_debug("Failed to wait for async response [rc=%d]\n", | |
69 | rc); | |
70 | break; | |
71 | } | |
72 | rc = opal_get_async_rc(msg); | |
73 | if (rc != OPAL_SUCCESS) { | |
74 | pr_debug("OPAL async call returned failed [rc=%d]\n", | |
75 | rc); | |
76 | break; | |
77 | } | |
479857a9 | 78 | break; |
43a1dd9b SJS |
79 | case OPAL_SUCCESS: |
80 | break; | |
81 | default: | |
82 | pr_debug("OPAL write op-panel call failed [rc=%d]\n", rc); | |
83 | } | |
84 | ||
85 | opal_async_release_token(token); | |
86 | return rc; | |
87 | } | |
88 | ||
89 | static ssize_t oppanel_write(struct file *filp, const char __user *userbuf, | |
90 | size_t len, loff_t *f_pos) | |
91 | { | |
92 | loff_t f_pos_prev = *f_pos; | |
93 | ssize_t ret; | |
94 | int rc; | |
95 | ||
96 | if (!*f_pos) | |
97 | memset(oppanel_data, ' ', oppanel_size); | |
98 | else if (*f_pos >= oppanel_size) | |
99 | return -EFBIG; | |
100 | ||
101 | ret = simple_write_to_buffer(oppanel_data, oppanel_size, f_pos, userbuf, | |
102 | len); | |
103 | if (ret > 0) { | |
104 | rc = __op_panel_update_display(); | |
105 | if (rc != OPAL_SUCCESS) { | |
106 | pr_err_ratelimited("OPAL call failed to write to op panel display [rc=%d]\n", | |
107 | rc); | |
108 | *f_pos = f_pos_prev; | |
109 | return -EIO; | |
110 | } | |
111 | } | |
112 | return ret; | |
113 | } | |
114 | ||
115 | static int oppanel_open(struct inode *inode, struct file *filp) | |
116 | { | |
117 | if (!mutex_trylock(&oppanel_mutex)) { | |
118 | pr_debug("Device Busy\n"); | |
119 | return -EBUSY; | |
120 | } | |
121 | return 0; | |
122 | } | |
123 | ||
124 | static int oppanel_release(struct inode *inode, struct file *filp) | |
125 | { | |
126 | mutex_unlock(&oppanel_mutex); | |
127 | return 0; | |
128 | } | |
129 | ||
130 | static const struct file_operations oppanel_fops = { | |
131 | .owner = THIS_MODULE, | |
132 | .llseek = oppanel_llseek, | |
133 | .read = oppanel_read, | |
134 | .write = oppanel_write, | |
135 | .open = oppanel_open, | |
136 | .release = oppanel_release | |
137 | }; | |
138 | ||
139 | static struct miscdevice oppanel_dev = { | |
140 | .minor = MISC_DYNAMIC_MINOR, | |
141 | .name = "op_panel", | |
142 | .fops = &oppanel_fops | |
143 | }; | |
144 | ||
145 | static int oppanel_probe(struct platform_device *pdev) | |
146 | { | |
147 | struct device_node *np = pdev->dev.of_node; | |
148 | u32 line_len; | |
149 | int rc, i; | |
150 | ||
151 | rc = of_property_read_u32(np, "#length", &line_len); | |
152 | if (rc) { | |
153 | pr_err_ratelimited("Operator panel length property not found\n"); | |
154 | return rc; | |
155 | } | |
156 | rc = of_property_read_u32(np, "#lines", &num_lines); | |
157 | if (rc) { | |
158 | pr_err_ratelimited("Operator panel lines property not found\n"); | |
159 | return rc; | |
160 | } | |
161 | oppanel_size = line_len * num_lines; | |
162 | ||
163 | pr_devel("Operator panel of size %u found with %u lines of length %u\n", | |
164 | oppanel_size, num_lines, line_len); | |
165 | ||
166 | oppanel_data = kcalloc(oppanel_size, sizeof(*oppanel_data), GFP_KERNEL); | |
167 | if (!oppanel_data) | |
168 | return -ENOMEM; | |
169 | ||
170 | oppanel_lines = kcalloc(num_lines, sizeof(oppanel_line_t), GFP_KERNEL); | |
171 | if (!oppanel_lines) { | |
172 | rc = -ENOMEM; | |
173 | goto free_oppanel_data; | |
174 | } | |
175 | ||
176 | memset(oppanel_data, ' ', oppanel_size); | |
177 | for (i = 0; i < num_lines; i++) { | |
178 | oppanel_lines[i].line_len = cpu_to_be64(line_len); | |
179 | oppanel_lines[i].line = cpu_to_be64(__pa(&oppanel_data[i * | |
180 | line_len])); | |
181 | } | |
182 | ||
183 | rc = misc_register(&oppanel_dev); | |
184 | if (rc) { | |
185 | pr_err_ratelimited("Failed to register as misc device\n"); | |
186 | goto free_oppanel; | |
187 | } | |
188 | ||
189 | return 0; | |
190 | ||
191 | free_oppanel: | |
192 | kfree(oppanel_lines); | |
193 | free_oppanel_data: | |
194 | kfree(oppanel_data); | |
195 | return rc; | |
196 | } | |
197 | ||
198 | static int oppanel_remove(struct platform_device *pdev) | |
199 | { | |
200 | misc_deregister(&oppanel_dev); | |
201 | kfree(oppanel_lines); | |
202 | kfree(oppanel_data); | |
203 | return 0; | |
204 | } | |
205 | ||
206 | static const struct of_device_id oppanel_match[] = { | |
207 | { .compatible = "ibm,opal-oppanel" }, | |
208 | { }, | |
209 | }; | |
210 | ||
211 | static struct platform_driver oppanel_driver = { | |
212 | .driver = { | |
213 | .name = "powernv-op-panel", | |
214 | .of_match_table = oppanel_match, | |
215 | }, | |
216 | .probe = oppanel_probe, | |
217 | .remove = oppanel_remove, | |
218 | }; | |
219 | ||
220 | module_platform_driver(oppanel_driver); | |
221 | ||
222 | MODULE_DEVICE_TABLE(of, oppanel_match); | |
223 | MODULE_LICENSE("GPL v2"); | |
224 | MODULE_DESCRIPTION("PowerNV Operator Panel LCD Display Driver"); | |
225 | MODULE_AUTHOR("Suraj Jitindar Singh <sjitindarsingh@gmail.com>"); |