1 /*-
2 * Copyright (c) 2006 M. Warner Losh. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23 */
24
25 #include <sys/cdefs.h>
26 __FBSDID("$FreeBSD: releng/7.3/sys/arm/at91/at91_twi.c 180911 2008-07-28 16:20:08Z thompsa $");
27
28 #include <sys/param.h>
29 #include <sys/systm.h>
30 #include <sys/bus.h>
31 #include <sys/conf.h>
32 #include <sys/kernel.h>
33 #include <sys/lock.h>
34 #include <sys/mbuf.h>
35 #include <sys/malloc.h>
36 #include <sys/module.h>
37 #include <sys/mutex.h>
38 #include <sys/rman.h>
39 #include <machine/bus.h>
40
41 #include <arm/at91/at91rm92reg.h>
42 #include <arm/at91/at91_twireg.h>
43
44 #include <dev/iicbus/iiconf.h>
45 #include <dev/iicbus/iicbus.h>
46 #include "iicbus_if.h"
47
48 #define TWI_SLOW_CLOCK 1500
49 #define TWI_FAST_CLOCK 45000
50 #define TWI_FASTEST_CLOCK 90000
51
52 struct at91_twi_softc
53 {
54 device_t dev; /* Myself */
55 void *intrhand; /* Interrupt handle */
56 struct resource *irq_res; /* IRQ resource */
57 struct resource *mem_res; /* Memory resource */
58 struct mtx sc_mtx; /* basically a perimeter lock */
59 volatile uint32_t flags;
60 uint32_t cwgr;
61 int sc_started;
62 int twi_addr;
63 device_t iicbus;
64 };
65
66 static inline uint32_t
67 RD4(struct at91_twi_softc *sc, bus_size_t off)
68 {
69 return bus_read_4(sc->mem_res, off);
70 }
71
72 static inline void
73 WR4(struct at91_twi_softc *sc, bus_size_t off, uint32_t val)
74 {
75 bus_write_4(sc->mem_res, off, val);
76 }
77
78 #define AT91_TWI_LOCK(_sc) mtx_lock(&(_sc)->sc_mtx)
79 #define AT91_TWI_UNLOCK(_sc) mtx_unlock(&(_sc)->sc_mtx)
80 #define AT91_TWI_LOCK_INIT(_sc) \
81 mtx_init(&_sc->sc_mtx, device_get_nameunit(_sc->dev), \
82 "twi", MTX_DEF)
83 #define AT91_TWI_LOCK_DESTROY(_sc) mtx_destroy(&_sc->sc_mtx);
84 #define AT91_TWI_ASSERT_LOCKED(_sc) mtx_assert(&_sc->sc_mtx, MA_OWNED);
85 #define AT91_TWI_ASSERT_UNLOCKED(_sc) mtx_assert(&_sc->sc_mtx, MA_NOTOWNED);
86 #define TWI_DEF_CLK 100000
87
88 static devclass_t at91_twi_devclass;
89
90 /* bus entry points */
91
92 static int at91_twi_probe(device_t dev);
93 static int at91_twi_attach(device_t dev);
94 static int at91_twi_detach(device_t dev);
95 static void at91_twi_intr(void *);
96
97 /* helper routines */
98 static int at91_twi_activate(device_t dev);
99 static void at91_twi_deactivate(device_t dev);
100
101 static int
102 at91_twi_probe(device_t dev)
103 {
104 device_set_desc(dev, "TWI");
105 return (0);
106 }
107
108 static int
109 at91_twi_attach(device_t dev)
110 {
111 struct at91_twi_softc *sc = device_get_softc(dev);
112 int err;
113
114 sc->dev = dev;
115 err = at91_twi_activate(dev);
116 if (err)
117 goto out;
118
119 AT91_TWI_LOCK_INIT(sc);
120
121 /*
122 * Activate the interrupt
123 */
124 err = bus_setup_intr(dev, sc->irq_res, INTR_TYPE_MISC | INTR_MPSAFE,
125 NULL, at91_twi_intr, sc, &sc->intrhand);
126 if (err) {
127 AT91_TWI_LOCK_DESTROY(sc);
128 goto out;
129 }
130 sc->cwgr = TWI_CWGR_CKDIV(8 * AT91C_MASTER_CLOCK / TWI_FASTEST_CLOCK) |
131 TWI_CWGR_CHDIV(TWI_CWGR_DIV(TWI_DEF_CLK)) |
132 TWI_CWGR_CLDIV(TWI_CWGR_DIV(TWI_DEF_CLK));
133 WR4(sc, TWI_CR, TWI_CR_SWRST);
134 WR4(sc, TWI_CR, TWI_CR_MSEN | TWI_CR_SVDIS);
135 WR4(sc, TWI_CWGR, sc->cwgr);
136
137 if ((sc->iicbus = device_add_child(dev, "iicbus", -1)) == NULL)
138 device_printf(dev, "could not allocate iicbus instance\n");
139 /* probe and attach the iicbus */
140 bus_generic_attach(dev);
141 out:;
142 if (err)
143 at91_twi_deactivate(dev);
144 return (err);
145 }
146
147 static int
148 at91_twi_detach(device_t dev)
149 {
150 struct at91_twi_softc *sc;
151 int rv;
152
153 sc = device_get_softc(dev);
154 at91_twi_deactivate(dev);
155 if (sc->iicbus && (rv = device_delete_child(dev, sc->iicbus)) != 0)
156 return (rv);
157
158 return (0);
159 }
160
161 static int
162 at91_twi_activate(device_t dev)
163 {
164 struct at91_twi_softc *sc;
165 int rid;
166
167 sc = device_get_softc(dev);
168 rid = 0;
169 sc->mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
170 RF_ACTIVE);
171 if (sc->mem_res == NULL)
172 goto errout;
173 rid = 0;
174 sc->irq_res = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
175 RF_ACTIVE);
176 if (sc->irq_res == NULL)
177 goto errout;
178 return (0);
179 errout:
180 at91_twi_deactivate(dev);
181 return (ENOMEM);
182 }
183
184 static void
185 at91_twi_deactivate(device_t dev)
186 {
187 struct at91_twi_softc *sc;
188
189 sc = device_get_softc(dev);
190 if (sc->intrhand)
191 bus_teardown_intr(dev, sc->irq_res, sc->intrhand);
192 sc->intrhand = 0;
193 bus_generic_detach(sc->dev);
194 if (sc->mem_res)
195 bus_release_resource(dev, SYS_RES_MEMORY,
196 rman_get_rid(sc->mem_res), sc->mem_res);
197 sc->mem_res = 0;
198 if (sc->irq_res)
199 bus_release_resource(dev, SYS_RES_IRQ,
200 rman_get_rid(sc->irq_res), sc->irq_res);
201 sc->irq_res = 0;
202 return;
203 }
204
205 static void
206 at91_twi_intr(void *xsc)
207 {
208 struct at91_twi_softc *sc = xsc;
209 uint32_t status;
210
211 status = RD4(sc, TWI_SR);
212 if (status == 0)
213 return;
214 sc->flags |= status & (TWI_SR_OVRE | TWI_SR_UNRE | TWI_SR_NACK);
215 if (status & TWI_SR_RXRDY)
216 sc->flags |= TWI_SR_RXRDY;
217 if (status & TWI_SR_TXRDY)
218 sc->flags |= TWI_SR_TXRDY;
219 if (status & TWI_SR_TXCOMP)
220 sc->flags |= TWI_SR_TXCOMP;
221 WR4(sc, TWI_IDR, status);
222 wakeup(sc);
223 return;
224 }
225
226 static int
227 at91_twi_wait(struct at91_twi_softc *sc, uint32_t bit)
228 {
229 int err = 0;
230 int counter = 100000;
231 uint32_t sr;
232
233 while (!((sr = RD4(sc, TWI_SR)) & bit) && counter-- > 0 &&
234 !(sr & TWI_SR_NACK))
235 continue;
236 if (counter <= 0)
237 err = EBUSY;
238 else if (sr & TWI_SR_NACK)
239 err = ENXIO; // iic nack convention
240 return (err);
241 }
242
243 static int
244 at91_twi_rst_card(device_t dev, u_char speed, u_char addr, u_char *oldaddr)
245 {
246 struct at91_twi_softc *sc;
247 int clk;
248
249 sc = device_get_softc(dev);
250 if (oldaddr)
251 *oldaddr = sc->twi_addr;
252 sc->twi_addr = addr;
253
254 /*
255 * speeds are for 1.5kb/s, 45kb/s and 90kb/s.
256 */
257 switch (speed) {
258 case IIC_SLOW:
259 clk = TWI_SLOW_CLOCK;
260 break;
261
262 case IIC_FAST:
263 clk = TWI_FAST_CLOCK;
264 break;
265
266 case IIC_UNKNOWN:
267 case IIC_FASTEST:
268 default:
269 clk = TWI_FASTEST_CLOCK;
270 break;
271 }
272 sc->cwgr = TWI_CWGR_CKDIV(1) | TWI_CWGR_CHDIV(TWI_CWGR_DIV(clk)) |
273 TWI_CWGR_CLDIV(TWI_CWGR_DIV(clk));
274 WR4(sc, TWI_CR, TWI_CR_SWRST);
275 WR4(sc, TWI_CR, TWI_CR_MSEN | TWI_CR_SVDIS);
276 WR4(sc, TWI_CWGR, sc->cwgr);
277 printf("setting cwgr to %#x\n", sc->cwgr);
278
279 return 0;
280 }
281
282 static int
283 at91_twi_callback(device_t dev, int index, caddr_t *data)
284 {
285 int error = 0;
286
287 switch (index) {
288 case IIC_REQUEST_BUS:
289 break;
290
291 case IIC_RELEASE_BUS:
292 break;
293
294 default:
295 error = EINVAL;
296 }
297
298 return (error);
299 }
300
301 static int
302 at91_twi_transfer(device_t dev, struct iic_msg *msgs, uint32_t nmsgs)
303 {
304 struct at91_twi_softc *sc;
305 int i, len, err;
306 uint32_t rdwr;
307 uint8_t *buf;
308 uint32_t sr;
309
310 sc = device_get_softc(dev);
311 err = 0;
312 AT91_TWI_LOCK(sc);
313 for (i = 0; i < nmsgs; i++) {
314 /*
315 * The linux atmel driver doesn't use the internal device
316 * address feature of twi. A separate i2c message needs to
317 * be written to use this.
318 * See http://lists.arm.linux.org.uk/pipermail/linux-arm-kernel/2004-September/024411.html
319 * for details. Upon reflection, we could use this as an
320 * optimization, but it is unclear the code bloat will
321 * result in faster/better operations.
322 */
323 rdwr = (msgs[i].flags & IIC_M_RD) ? TWI_MMR_MREAD : 0;
324 WR4(sc, TWI_MMR, TWI_MMR_DADR(msgs[i].slave) | rdwr);
325 len = msgs[i].len;
326 buf = msgs[i].buf;
327 /* zero byte transfers aren't allowed */
328 if (len == 0 || buf == NULL) {
329 err = EINVAL;
330 goto out;
331 }
332 if (len == 1)
333 WR4(sc, TWI_CR, TWI_CR_START | TWI_CR_STOP);
334 else
335 WR4(sc, TWI_CR, TWI_CR_START);
336 if (msgs[i].flags & IIC_M_RD) {
337 sr = RD4(sc, TWI_SR);
338 while (!(sr & TWI_SR_TXCOMP)) {
339 if ((sr = RD4(sc, TWI_SR)) & TWI_SR_RXRDY) {
340 len--;
341 *buf++ = RD4(sc, TWI_RHR) & 0xff;
342 if (len == 0 && msgs[i].len != 1)
343 WR4(sc, TWI_CR, TWI_CR_STOP);
344 }
345 }
346 if (len > 0 || (sr & TWI_SR_NACK)) {
347 err = ENXIO; // iic nack convention
348 goto out;
349 }
350 } else {
351 while (len--) {
352 if (len == 0 && msgs[i].len != 1)
353 WR4(sc, TWI_CR, TWI_CR_STOP);
354 if ((err = at91_twi_wait(sc, TWI_SR_TXRDY)))
355 goto out;
356 WR4(sc, TWI_THR, *buf++);
357 }
358 }
359 if ((err = at91_twi_wait(sc, TWI_SR_TXCOMP)))
360 break;
361 }
362 out:;
363 if (err) {
364 WR4(sc, TWI_CR, TWI_CR_SWRST);
365 WR4(sc, TWI_CR, TWI_CR_MSEN | TWI_CR_SVDIS);
366 WR4(sc, TWI_CWGR, sc->cwgr);
367 }
368 AT91_TWI_UNLOCK(sc);
369 return (err);
370 }
371
372 static device_method_t at91_twi_methods[] = {
373 /* Device interface */
374 DEVMETHOD(device_probe, at91_twi_probe),
375 DEVMETHOD(device_attach, at91_twi_attach),
376 DEVMETHOD(device_detach, at91_twi_detach),
377
378 /* iicbus interface */
379 DEVMETHOD(iicbus_callback, at91_twi_callback),
380 DEVMETHOD(iicbus_reset, at91_twi_rst_card),
381 DEVMETHOD(iicbus_transfer, at91_twi_transfer),
382 { 0, 0 }
383 };
384
385 static driver_t at91_twi_driver = {
386 "at91_twi",
387 at91_twi_methods,
388 sizeof(struct at91_twi_softc),
389 };
390
391 DRIVER_MODULE(at91_twi, atmelarm, at91_twi_driver, at91_twi_devclass, 0, 0);
392 DRIVER_MODULE(iicbus, at91_twi, iicbus_driver, iicbus_devclass, 0, 0);
393 MODULE_DEPEND(at91_twi, iicbus, 1, 1, 1);
Cache object: 7787fcc333e606bdbc220796698852c8
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