1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Driver for the ADB controller in the Mac I/O (Hydra) chip.
4 */
5 #include <linux/types.h>
6 #include <linux/errno.h>
7 #include <linux/kernel.h>
8 #include <linux/delay.h>
9 #include <linux/spinlock.h>
10 #include <linux/interrupt.h>
11 #include <linux/pgtable.h>
12 #include <linux/of.h>
13 #include <linux/of_address.h>
14 #include <linux/of_irq.h>
15 #include <linux/adb.h>
16
17 #include <asm/io.h>
18 #include <asm/hydra.h>
19 #include <asm/irq.h>
20 #include <linux/init.h>
21 #include <linux/ioport.h>
22
23 struct preg {
24 unsigned char r;
25 char pad[15];
26 };
27
28 struct adb_regs {
29 struct preg intr;
30 struct preg data[9];
31 struct preg intr_enb;
32 struct preg dcount;
33 struct preg error;
34 struct preg ctrl;
35 struct preg autopoll;
36 struct preg active_hi;
37 struct preg active_lo;
38 struct preg test;
39 };
40
41 /* Bits in intr and intr_enb registers */
42 #define DFB 1 /* data from bus */
43 #define TAG 2 /* transfer access grant */
44
45 /* Bits in dcount register */
46 #define HMB 0x0f /* how many bytes */
47 #define APD 0x10 /* auto-poll data */
48
49 /* Bits in error register */
50 #define NRE 1 /* no response error */
51 #define DLE 2 /* data lost error */
52
53 /* Bits in ctrl register */
54 #define TAR 1 /* transfer access request */
55 #define DTB 2 /* data to bus */
56 #define CRE 4 /* command response expected */
57 #define ADB_RST 8 /* ADB reset */
58
59 /* Bits in autopoll register */
60 #define APE 1 /* autopoll enable */
61
62 static volatile struct adb_regs __iomem *adb;
63 static struct adb_request *current_req, *last_req;
64 static DEFINE_SPINLOCK(macio_lock);
65
66 static int macio_probe(void);
67 static int macio_init(void);
68 static irqreturn_t macio_adb_interrupt(int irq, void *arg);
69 static int macio_send_request(struct adb_request *req, int sync);
70 static int macio_adb_autopoll(int devs);
71 static void macio_adb_poll(void);
72 static int macio_adb_reset_bus(void);
73
74 struct adb_driver macio_adb_driver = {
75 .name = "MACIO",
76 .probe = macio_probe,
77 .init = macio_init,
78 .send_request = macio_send_request,
79 .autopoll = macio_adb_autopoll,
80 .poll = macio_adb_poll,
81 .reset_bus = macio_adb_reset_bus,
82 };
83
macio_probe(void)84 int macio_probe(void)
85 {
86 struct device_node *np;
87
88 np = of_find_compatible_node(NULL, "adb", "chrp,adb0");
89 if (np) {
90 of_node_put(np);
91 return 0;
92 }
93 return -ENODEV;
94 }
95
macio_init(void)96 int macio_init(void)
97 {
98 struct device_node *adbs;
99 struct resource r;
100 unsigned int irq;
101
102 adbs = of_find_compatible_node(NULL, "adb", "chrp,adb0");
103 if (!adbs)
104 return -ENXIO;
105
106 if (of_address_to_resource(adbs, 0, &r)) {
107 of_node_put(adbs);
108 return -ENXIO;
109 }
110 adb = ioremap(r.start, sizeof(struct adb_regs));
111 if (!adb) {
112 of_node_put(adbs);
113 return -ENOMEM;
114 }
115
116 out_8(&adb->ctrl.r, 0);
117 out_8(&adb->intr.r, 0);
118 out_8(&adb->error.r, 0);
119 out_8(&adb->active_hi.r, 0xff); /* for now, set all devices active */
120 out_8(&adb->active_lo.r, 0xff);
121 out_8(&adb->autopoll.r, APE);
122
123 irq = irq_of_parse_and_map(adbs, 0);
124 of_node_put(adbs);
125 if (request_irq(irq, macio_adb_interrupt, 0, "ADB", (void *)0)) {
126 printk(KERN_ERR "ADB: can't get irq %d\n", irq);
127 return -EAGAIN;
128 }
129 out_8(&adb->intr_enb.r, DFB | TAG);
130
131 printk("adb: mac-io driver 1.0 for unified ADB\n");
132
133 return 0;
134 }
135
macio_adb_autopoll(int devs)136 static int macio_adb_autopoll(int devs)
137 {
138 unsigned long flags;
139
140 spin_lock_irqsave(&macio_lock, flags);
141 out_8(&adb->active_hi.r, devs >> 8);
142 out_8(&adb->active_lo.r, devs);
143 out_8(&adb->autopoll.r, devs? APE: 0);
144 spin_unlock_irqrestore(&macio_lock, flags);
145 return 0;
146 }
147
macio_adb_reset_bus(void)148 static int macio_adb_reset_bus(void)
149 {
150 unsigned long flags;
151 int timeout = 1000000;
152
153 /* Hrm... we may want to not lock interrupts for so
154 * long ... oh well, who uses that chip anyway ? :)
155 * That function will be seldom used during boot
156 * on rare machines, so...
157 */
158 spin_lock_irqsave(&macio_lock, flags);
159 out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | ADB_RST);
160 while ((in_8(&adb->ctrl.r) & ADB_RST) != 0) {
161 if (--timeout == 0) {
162 out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) & ~ADB_RST);
163 spin_unlock_irqrestore(&macio_lock, flags);
164 return -1;
165 }
166 }
167 spin_unlock_irqrestore(&macio_lock, flags);
168 return 0;
169 }
170
171 /* Send an ADB command */
macio_send_request(struct adb_request * req,int sync)172 static int macio_send_request(struct adb_request *req, int sync)
173 {
174 unsigned long flags;
175 int i;
176
177 if (req->data[0] != ADB_PACKET)
178 return -EINVAL;
179
180 for (i = 0; i < req->nbytes - 1; ++i)
181 req->data[i] = req->data[i+1];
182 --req->nbytes;
183
184 req->next = NULL;
185 req->sent = 0;
186 req->complete = 0;
187 req->reply_len = 0;
188
189 spin_lock_irqsave(&macio_lock, flags);
190 if (current_req) {
191 last_req->next = req;
192 last_req = req;
193 } else {
194 current_req = last_req = req;
195 out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);
196 }
197 spin_unlock_irqrestore(&macio_lock, flags);
198
199 if (sync) {
200 while (!req->complete)
201 macio_adb_poll();
202 }
203
204 return 0;
205 }
206
macio_adb_interrupt(int irq,void * arg)207 static irqreturn_t macio_adb_interrupt(int irq, void *arg)
208 {
209 int i, n, err;
210 struct adb_request *req = NULL;
211 unsigned char ibuf[16];
212 int ibuf_len = 0;
213 int complete = 0;
214 int autopoll = 0;
215 int handled = 0;
216
217 spin_lock(&macio_lock);
218 if (in_8(&adb->intr.r) & TAG) {
219 handled = 1;
220 req = current_req;
221 if (req) {
222 /* put the current request in */
223 for (i = 0; i < req->nbytes; ++i)
224 out_8(&adb->data[i].r, req->data[i]);
225 out_8(&adb->dcount.r, req->nbytes & HMB);
226 req->sent = 1;
227 if (req->reply_expected) {
228 out_8(&adb->ctrl.r, DTB + CRE);
229 } else {
230 out_8(&adb->ctrl.r, DTB);
231 current_req = req->next;
232 complete = 1;
233 if (current_req)
234 out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);
235 }
236 }
237 out_8(&adb->intr.r, 0);
238 }
239
240 if (in_8(&adb->intr.r) & DFB) {
241 handled = 1;
242 err = in_8(&adb->error.r);
243 if (current_req && current_req->sent) {
244 /* this is the response to a command */
245 req = current_req;
246 if (err == 0) {
247 req->reply_len = in_8(&adb->dcount.r) & HMB;
248 for (i = 0; i < req->reply_len; ++i)
249 req->reply[i] = in_8(&adb->data[i].r);
250 }
251 current_req = req->next;
252 complete = 1;
253 if (current_req)
254 out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);
255 } else if (err == 0) {
256 /* autopoll data */
257 n = in_8(&adb->dcount.r) & HMB;
258 for (i = 0; i < n; ++i)
259 ibuf[i] = in_8(&adb->data[i].r);
260 ibuf_len = n;
261 autopoll = (in_8(&adb->dcount.r) & APD) != 0;
262 }
263 out_8(&adb->error.r, 0);
264 out_8(&adb->intr.r, 0);
265 }
266 spin_unlock(&macio_lock);
267 if (complete && req) {
268 void (*done)(struct adb_request *) = req->done;
269 mb();
270 req->complete = 1;
271 /* Here, we assume that if the request has a done member, the
272 * struct request will survive to setting req->complete to 1
273 */
274 if (done)
275 (*done)(req);
276 }
277 if (ibuf_len)
278 adb_input(ibuf, ibuf_len, autopoll);
279
280 return IRQ_RETVAL(handled);
281 }
282
macio_adb_poll(void)283 static void macio_adb_poll(void)
284 {
285 unsigned long flags;
286
287 local_irq_save(flags);
288 if (in_8(&adb->intr.r) != 0)
289 macio_adb_interrupt(0, NULL);
290 local_irq_restore(flags);
291 }
292