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