1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Parallel port device probing code |
4 | * |
5 | * Authors: Carsten Gross, carsten@sol.wohnheim.uni-ulm.de |
6 | * Philip Blundell <philb@gnu.org> |
7 | */ |
8 | |
9 | #include <linux/module.h> |
10 | #include <linux/parport.h> |
11 | #include <linux/string.h> |
12 | #include <linux/string_helpers.h> |
13 | #include <linux/slab.h> |
14 | #include <linux/uaccess.h> |
15 | |
16 | static const struct { |
17 | const char *token; |
18 | const char *descr; |
19 | } classes[] = { |
20 | { "" , "Legacy device" }, |
21 | { "PRINTER" , "Printer" }, |
22 | { "MODEM" , "Modem" }, |
23 | { "NET" , "Network device" }, |
24 | { "HDC" , "Hard disk" }, |
25 | { "PCMCIA" , "PCMCIA" }, |
26 | { "MEDIA" , "Multimedia device" }, |
27 | { "FDC" , "Floppy disk" }, |
28 | { "PORTS" , "Ports" }, |
29 | { "SCANNER" , "Scanner" }, |
30 | { "DIGICAM" , "Digital camera" }, |
31 | { "" , "Unknown device" }, |
32 | { "" , "Unspecified" }, |
33 | { "SCSIADAPTER" , "SCSI adapter" }, |
34 | { NULL, NULL } |
35 | }; |
36 | |
37 | static void pretty_print(struct parport *port, int device) |
38 | { |
39 | struct parport_device_info *info = &port->probe_info[device + 1]; |
40 | |
41 | pr_info("%s" , port->name); |
42 | |
43 | if (device >= 0) |
44 | pr_cont(" (addr %d)" , device); |
45 | |
46 | pr_cont(": %s" , classes[info->class].descr); |
47 | if (info->class) |
48 | pr_cont(", %s %s" , info->mfr, info->model); |
49 | |
50 | pr_cont("\n" ); |
51 | } |
52 | |
53 | static void parse_data(struct parport *port, int device, char *str) |
54 | { |
55 | char *txt = kmalloc(strlen(str)+1, GFP_KERNEL); |
56 | char *p = txt, *q; |
57 | int guessed_class = PARPORT_CLASS_UNSPEC; |
58 | struct parport_device_info *info = &port->probe_info[device + 1]; |
59 | |
60 | if (!txt) { |
61 | pr_warn("%s probe: memory squeeze\n" , port->name); |
62 | return; |
63 | } |
64 | strcpy(p: txt, q: str); |
65 | while (p) { |
66 | char *sep; |
67 | q = strchr(p, ';'); |
68 | if (q) *q = 0; |
69 | sep = strchr(p, ':'); |
70 | if (sep) { |
71 | char *u; |
72 | *(sep++) = 0; |
73 | /* Get rid of trailing blanks */ |
74 | u = sep + strlen (sep) - 1; |
75 | while (u >= p && *u == ' ') |
76 | *u-- = '\0'; |
77 | string_upper(dst: p, src: p); |
78 | if (!strcmp(p, "MFG" ) || !strcmp(p, "MANUFACTURER" )) { |
79 | kfree(objp: info->mfr); |
80 | info->mfr = kstrdup(s: sep, GFP_KERNEL); |
81 | } else if (!strcmp(p, "MDL" ) || !strcmp(p, "MODEL" )) { |
82 | kfree(objp: info->model); |
83 | info->model = kstrdup(s: sep, GFP_KERNEL); |
84 | } else if (!strcmp(p, "CLS" ) || !strcmp(p, "CLASS" )) { |
85 | int i; |
86 | |
87 | kfree(objp: info->class_name); |
88 | info->class_name = kstrdup(s: sep, GFP_KERNEL); |
89 | string_upper(dst: sep, src: sep); |
90 | for (i = 0; classes[i].token; i++) { |
91 | if (!strcmp(classes[i].token, sep)) { |
92 | info->class = i; |
93 | goto rock_on; |
94 | } |
95 | } |
96 | pr_warn("%s probe: warning, class '%s' not understood\n" , |
97 | port->name, sep); |
98 | info->class = PARPORT_CLASS_OTHER; |
99 | } else if (!strcmp(p, "CMD" ) || |
100 | !strcmp(p, "COMMAND SET" )) { |
101 | kfree(objp: info->cmdset); |
102 | info->cmdset = kstrdup(s: sep, GFP_KERNEL); |
103 | /* if it speaks printer language, it's |
104 | probably a printer */ |
105 | if (strstr(sep, "PJL" ) || strstr(sep, "PCL" )) |
106 | guessed_class = PARPORT_CLASS_PRINTER; |
107 | } else if (!strcmp(p, "DES" ) || !strcmp(p, "DESCRIPTION" )) { |
108 | kfree(objp: info->description); |
109 | info->description = kstrdup(s: sep, GFP_KERNEL); |
110 | } |
111 | } |
112 | rock_on: |
113 | if (q) |
114 | p = q + 1; |
115 | else |
116 | p = NULL; |
117 | } |
118 | |
119 | /* If the device didn't tell us its class, maybe we have managed to |
120 | guess one from the things it did say. */ |
121 | if (info->class == PARPORT_CLASS_UNSPEC) |
122 | info->class = guessed_class; |
123 | |
124 | pretty_print (port, device); |
125 | |
126 | kfree(objp: txt); |
127 | } |
128 | |
129 | /* Read up to count-1 bytes of device id. Terminate buffer with |
130 | * '\0'. Buffer begins with two Device ID length bytes as given by |
131 | * device. */ |
132 | static ssize_t parport_read_device_id (struct parport *port, char *buffer, |
133 | size_t count) |
134 | { |
135 | unsigned char length[2]; |
136 | unsigned lelen, belen; |
137 | size_t idlens[4]; |
138 | unsigned numidlens; |
139 | unsigned current_idlen; |
140 | ssize_t retval; |
141 | size_t len; |
142 | |
143 | /* First two bytes are MSB,LSB of inclusive length. */ |
144 | retval = parport_read (port, buf: length, len: 2); |
145 | |
146 | if (retval < 0) |
147 | return retval; |
148 | if (retval != 2) |
149 | return -EIO; |
150 | |
151 | if (count < 2) |
152 | return 0; |
153 | memcpy(buffer, length, 2); |
154 | len = 2; |
155 | |
156 | /* Some devices wrongly send LE length, and some send it two |
157 | * bytes short. Construct a sorted array of lengths to try. */ |
158 | belen = (length[0] << 8) + length[1]; |
159 | lelen = (length[1] << 8) + length[0]; |
160 | idlens[0] = min(belen, lelen); |
161 | idlens[1] = idlens[0]+2; |
162 | if (belen != lelen) { |
163 | int off = 2; |
164 | /* Don't try lengths of 0x100 and 0x200 as 1 and 2 */ |
165 | if (idlens[0] <= 2) |
166 | off = 0; |
167 | idlens[off] = max(belen, lelen); |
168 | idlens[off+1] = idlens[off]+2; |
169 | numidlens = off+2; |
170 | } |
171 | else { |
172 | /* Some devices don't truly implement Device ID, but |
173 | * just return constant nibble forever. This catches |
174 | * also those cases. */ |
175 | if (idlens[0] == 0 || idlens[0] > 0xFFF) { |
176 | printk(KERN_DEBUG "%s: reported broken Device ID length of %#zX bytes\n" , |
177 | port->name, idlens[0]); |
178 | return -EIO; |
179 | } |
180 | numidlens = 2; |
181 | } |
182 | |
183 | /* Try to respect the given ID length despite all the bugs in |
184 | * the ID length. Read according to shortest possible ID |
185 | * first. */ |
186 | for (current_idlen = 0; current_idlen < numidlens; ++current_idlen) { |
187 | size_t idlen = idlens[current_idlen]; |
188 | if (idlen+1 >= count) |
189 | break; |
190 | |
191 | retval = parport_read (port, buf: buffer+len, len: idlen-len); |
192 | |
193 | if (retval < 0) |
194 | return retval; |
195 | len += retval; |
196 | |
197 | if (port->physport->ieee1284.phase != IEEE1284_PH_HBUSY_DAVAIL) { |
198 | if (belen != len) { |
199 | printk(KERN_DEBUG "%s: Device ID was %zd bytes while device told it would be %d bytes\n" , |
200 | port->name, len, belen); |
201 | } |
202 | goto done; |
203 | } |
204 | |
205 | /* This might end reading the Device ID too |
206 | * soon. Hopefully the needed fields were already in |
207 | * the first 256 bytes or so that we must have read so |
208 | * far. */ |
209 | if (buffer[len-1] == ';') { |
210 | printk(KERN_DEBUG "%s: Device ID reading stopped before device told data not available. Current idlen %u of %u, len bytes %02X %02X\n" , |
211 | port->name, current_idlen, numidlens, |
212 | length[0], length[1]); |
213 | goto done; |
214 | } |
215 | } |
216 | if (current_idlen < numidlens) { |
217 | /* Buffer not large enough, read to end of buffer. */ |
218 | size_t idlen, len2; |
219 | if (len+1 < count) { |
220 | retval = parport_read (port, buf: buffer+len, len: count-len-1); |
221 | if (retval < 0) |
222 | return retval; |
223 | len += retval; |
224 | } |
225 | /* Read the whole ID since some devices would not |
226 | * otherwise give back the Device ID from beginning |
227 | * next time when asked. */ |
228 | idlen = idlens[current_idlen]; |
229 | len2 = len; |
230 | while(len2 < idlen && retval > 0) { |
231 | char tmp[4]; |
232 | retval = parport_read (port, buf: tmp, |
233 | min(sizeof tmp, idlen-len2)); |
234 | if (retval < 0) |
235 | return retval; |
236 | len2 += retval; |
237 | } |
238 | } |
239 | /* In addition, there are broken devices out there that don't |
240 | even finish off with a semi-colon. We do not need to care |
241 | about those at this time. */ |
242 | done: |
243 | buffer[len] = '\0'; |
244 | return len; |
245 | } |
246 | |
247 | /* Get Std 1284 Device ID. */ |
248 | ssize_t parport_device_id (int devnum, char *buffer, size_t count) |
249 | { |
250 | ssize_t retval = -ENXIO; |
251 | struct pardevice *dev = parport_open(devnum, daisy_dev_name); |
252 | if (!dev) |
253 | return -ENXIO; |
254 | |
255 | parport_claim_or_block (dev); |
256 | |
257 | /* Negotiate to compatibility mode, and then to device ID |
258 | * mode. (This so that we start form beginning of device ID if |
259 | * already in device ID mode.) */ |
260 | parport_negotiate (dev->port, IEEE1284_MODE_COMPAT); |
261 | retval = parport_negotiate (dev->port, |
262 | IEEE1284_MODE_NIBBLE | IEEE1284_DEVICEID); |
263 | |
264 | if (!retval) { |
265 | retval = parport_read_device_id (port: dev->port, buffer, count); |
266 | parport_negotiate (dev->port, IEEE1284_MODE_COMPAT); |
267 | if (retval > 2) |
268 | parse_data (port: dev->port, device: dev->daisy, str: buffer+2); |
269 | } |
270 | |
271 | parport_release (dev); |
272 | parport_close (dev); |
273 | return retval; |
274 | } |
275 | |