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 __free(device_node) =
87 of_find_compatible_node(NULL, "adb", "chrp,adb0");
88
89 if (np)
90 return 0;
91
92 return -ENODEV;
93 }
94
macio_init(void)95 int macio_init(void)
96 {
97 struct device_node *adbs __free(device_node) =
98 of_find_compatible_node(NULL, "adb", "chrp,adb0");
99 struct resource r;
100 unsigned int irq;
101
102 if (!adbs)
103 return -ENXIO;
104
105 if (of_address_to_resource(adbs, 0, &r))
106 return -ENXIO;
107
108 adb = ioremap(r.start, sizeof(struct adb_regs));
109 if (!adb)
110 return -ENOMEM;
111
112
113 out_8(&adb->ctrl.r, 0);
114 out_8(&adb->intr.r, 0);
115 out_8(&adb->error.r, 0);
116 out_8(&adb->active_hi.r, 0xff); /* for now, set all devices active */
117 out_8(&adb->active_lo.r, 0xff);
118 out_8(&adb->autopoll.r, APE);
119
120 irq = irq_of_parse_and_map(adbs, 0);
121 if (request_irq(irq, macio_adb_interrupt, 0, "ADB", (void *)0)) {
122 iounmap(adb);
123 printk(KERN_ERR "ADB: can't get irq %d\n", irq);
124 return -EAGAIN;
125 }
126 out_8(&adb->intr_enb.r, DFB | TAG);
127
128 printk("adb: mac-io driver 1.0 for unified ADB\n");
129
130 return 0;
131 }
132
macio_adb_autopoll(int devs)133 static int macio_adb_autopoll(int devs)
134 {
135 unsigned long flags;
136
137 spin_lock_irqsave(&macio_lock, flags);
138 out_8(&adb->active_hi.r, devs >> 8);
139 out_8(&adb->active_lo.r, devs);
140 out_8(&adb->autopoll.r, devs? APE: 0);
141 spin_unlock_irqrestore(&macio_lock, flags);
142 return 0;
143 }
144
macio_adb_reset_bus(void)145 static int macio_adb_reset_bus(void)
146 {
147 unsigned long flags;
148 int timeout = 1000000;
149
150 /* Hrm... we may want to not lock interrupts for so
151 * long ... oh well, who uses that chip anyway ? :)
152 * That function will be seldom used during boot
153 * on rare machines, so...
154 */
155 spin_lock_irqsave(&macio_lock, flags);
156 out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | ADB_RST);
157 while ((in_8(&adb->ctrl.r) & ADB_RST) != 0) {
158 if (--timeout == 0) {
159 out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) & ~ADB_RST);
160 spin_unlock_irqrestore(&macio_lock, flags);
161 return -1;
162 }
163 }
164 spin_unlock_irqrestore(&macio_lock, flags);
165 return 0;
166 }
167
168 /* Send an ADB command */
macio_send_request(struct adb_request * req,int sync)169 static int macio_send_request(struct adb_request *req, int sync)
170 {
171 unsigned long flags;
172 int i;
173
174 if (req->data[0] != ADB_PACKET)
175 return -EINVAL;
176
177 for (i = 0; i < req->nbytes - 1; ++i)
178 req->data[i] = req->data[i+1];
179 --req->nbytes;
180
181 req->next = NULL;
182 req->sent = 0;
183 req->complete = 0;
184 req->reply_len = 0;
185
186 spin_lock_irqsave(&macio_lock, flags);
187 if (current_req) {
188 last_req->next = req;
189 last_req = req;
190 } else {
191 current_req = last_req = req;
192 out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);
193 }
194 spin_unlock_irqrestore(&macio_lock, flags);
195
196 if (sync) {
197 while (!req->complete)
198 macio_adb_poll();
199 }
200
201 return 0;
202 }
203
macio_adb_interrupt(int irq,void * arg)204 static irqreturn_t macio_adb_interrupt(int irq, void *arg)
205 {
206 int i, n, err;
207 struct adb_request *req = NULL;
208 unsigned char ibuf[16];
209 int ibuf_len = 0;
210 int complete = 0;
211 int autopoll = 0;
212 int handled = 0;
213
214 spin_lock(&macio_lock);
215 if (in_8(&adb->intr.r) & TAG) {
216 handled = 1;
217 req = current_req;
218 if (req) {
219 /* put the current request in */
220 for (i = 0; i < req->nbytes; ++i)
221 out_8(&adb->data[i].r, req->data[i]);
222 out_8(&adb->dcount.r, req->nbytes & HMB);
223 req->sent = 1;
224 if (req->reply_expected) {
225 out_8(&adb->ctrl.r, DTB + CRE);
226 } else {
227 out_8(&adb->ctrl.r, DTB);
228 current_req = req->next;
229 complete = 1;
230 if (current_req)
231 out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);
232 }
233 }
234 out_8(&adb->intr.r, 0);
235 }
236
237 if (in_8(&adb->intr.r) & DFB) {
238 handled = 1;
239 err = in_8(&adb->error.r);
240 if (current_req && current_req->sent) {
241 /* this is the response to a command */
242 req = current_req;
243 if (err == 0) {
244 req->reply_len = in_8(&adb->dcount.r) & HMB;
245 for (i = 0; i < req->reply_len; ++i)
246 req->reply[i] = in_8(&adb->data[i].r);
247 }
248 current_req = req->next;
249 complete = 1;
250 if (current_req)
251 out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);
252 } else if (err == 0) {
253 /* autopoll data */
254 n = in_8(&adb->dcount.r) & HMB;
255 for (i = 0; i < n; ++i)
256 ibuf[i] = in_8(&adb->data[i].r);
257 ibuf_len = n;
258 autopoll = (in_8(&adb->dcount.r) & APD) != 0;
259 }
260 out_8(&adb->error.r, 0);
261 out_8(&adb->intr.r, 0);
262 }
263 spin_unlock(&macio_lock);
264 if (complete && req) {
265 void (*done)(struct adb_request *) = req->done;
266 mb();
267 req->complete = 1;
268 /* Here, we assume that if the request has a done member, the
269 * struct request will survive to setting req->complete to 1
270 */
271 if (done)
272 (*done)(req);
273 }
274 if (ibuf_len)
275 adb_input(ibuf, ibuf_len, autopoll);
276
277 return IRQ_RETVAL(handled);
278 }
279
macio_adb_poll(void)280 static void macio_adb_poll(void)
281 {
282 unsigned long flags;
283
284 local_irq_save(flags);
285 if (in_8(&adb->intr.r) != 0)
286 macio_adb_interrupt(0, NULL);
287 local_irq_restore(flags);
288 }
289