at91_twi.c revision 164744
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: head/sys/arm/at91/at91_twi.c 164744 2006-11-29 08:15:59Z imp $"); 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 48struct at91_twi_softc 49{ 50 device_t dev; /* Myself */ 51 void *intrhand; /* Interrupt handle */ 52 struct resource *irq_res; /* IRQ resource */ 53 struct resource *mem_res; /* Memory resource */ 54 struct mtx sc_mtx; /* basically a perimeter lock */ 55 volatile uint32_t flags; 56 uint32_t cwgr; 57 int sc_started; 58 int twi_addr; 59 device_t iicbus; 60}; 61 62static inline uint32_t 63RD4(struct at91_twi_softc *sc, bus_size_t off) 64{ 65 return bus_read_4(sc->mem_res, off); 66} 67 68static inline void 69WR4(struct at91_twi_softc *sc, bus_size_t off, uint32_t val) 70{ 71 bus_write_4(sc->mem_res, off, val); 72} 73 74#define AT91_TWI_LOCK(_sc) mtx_lock(&(_sc)->sc_mtx) 75#define AT91_TWI_UNLOCK(_sc) mtx_unlock(&(_sc)->sc_mtx) 76#define AT91_TWI_LOCK_INIT(_sc) \ 77 mtx_init(&_sc->sc_mtx, device_get_nameunit(_sc->dev), \ 78 "twi", MTX_DEF) 79#define AT91_TWI_LOCK_DESTROY(_sc) mtx_destroy(&_sc->sc_mtx); 80#define AT91_TWI_ASSERT_LOCKED(_sc) mtx_assert(&_sc->sc_mtx, MA_OWNED); 81#define AT91_TWI_ASSERT_UNLOCKED(_sc) mtx_assert(&_sc->sc_mtx, MA_NOTOWNED); 82#define TWI_DEF_CLK 100000 83 84static devclass_t at91_twi_devclass; 85 86/* bus entry points */ 87 88static int at91_twi_probe(device_t dev); 89static int at91_twi_attach(device_t dev); 90static int at91_twi_detach(device_t dev); 91static void at91_twi_intr(void *); 92 93/* helper routines */ 94static int at91_twi_activate(device_t dev); 95static void at91_twi_deactivate(device_t dev); 96 97static int 98at91_twi_probe(device_t dev) 99{ 100 device_set_desc(dev, "TWI"); 101 return (0); 102} 103 104static int 105at91_twi_attach(device_t dev) 106{ 107 struct at91_twi_softc *sc = device_get_softc(dev); 108 int err; 109 110 sc->dev = dev; 111 err = at91_twi_activate(dev); 112 if (err) 113 goto out; 114 115 AT91_TWI_LOCK_INIT(sc); 116 117 /* 118 * Activate the interrupt 119 */ 120 err = bus_setup_intr(dev, sc->irq_res, INTR_TYPE_MISC | INTR_MPSAFE, 121 at91_twi_intr, sc, &sc->intrhand); 122 if (err) { 123 AT91_TWI_LOCK_DESTROY(sc); 124 goto out; 125 } 126 sc->cwgr = TWI_CWGR_CKDIV(8 * AT91C_MASTER_CLOCK / 90000) | 127 TWI_CWGR_CHDIV(TWI_CWGR_DIV(TWI_DEF_CLK)) | 128 TWI_CWGR_CLDIV(TWI_CWGR_DIV(TWI_DEF_CLK)); 129 WR4(sc, TWI_CR, TWI_CR_SWRST); 130 WR4(sc, TWI_CR, TWI_CR_MSEN | TWI_CR_SVDIS); 131 WR4(sc, TWI_CWGR, sc->cwgr); 132 133 if ((sc->iicbus = device_add_child(dev, "iicbus", -1)) == NULL) 134 device_printf(dev, "could not allocate iicbus instance\n"); 135 /* probe and attach the iicbus */ 136 bus_generic_attach(dev); 137out:; 138 if (err) 139 at91_twi_deactivate(dev); 140 return (err); 141} 142 143static int 144at91_twi_detach(device_t dev) 145{ 146 struct at91_twi_softc *sc; 147 int rv; 148 149 sc = device_get_softc(dev); 150 at91_twi_deactivate(dev); 151 if (sc->iicbus && (rv = device_delete_child(dev, sc->iicbus)) != 0) 152 return (rv); 153 154 return (0); 155} 156 157static int 158at91_twi_activate(device_t dev) 159{ 160 struct at91_twi_softc *sc; 161 int rid; 162 163 sc = device_get_softc(dev); 164 rid = 0; 165 sc->mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, 166 RF_ACTIVE); 167 if (sc->mem_res == NULL) 168 goto errout; 169 rid = 0; 170 sc->irq_res = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid, 171 RF_ACTIVE); 172 if (sc->irq_res == NULL) 173 goto errout; 174 return (0); 175errout: 176 at91_twi_deactivate(dev); 177 return (ENOMEM); 178} 179 180static void 181at91_twi_deactivate(device_t dev) 182{ 183 struct at91_twi_softc *sc; 184 185 sc = device_get_softc(dev); 186 if (sc->intrhand) 187 bus_teardown_intr(dev, sc->irq_res, sc->intrhand); 188 sc->intrhand = 0; 189 bus_generic_detach(sc->dev); 190 if (sc->mem_res) 191 bus_release_resource(dev, SYS_RES_IOPORT, 192 rman_get_rid(sc->mem_res), sc->mem_res); 193 sc->mem_res = 0; 194 if (sc->irq_res) 195 bus_release_resource(dev, SYS_RES_IRQ, 196 rman_get_rid(sc->irq_res), sc->irq_res); 197 sc->irq_res = 0; 198 return; 199} 200 201static void 202at91_twi_intr(void *xsc) 203{ 204 struct at91_twi_softc *sc = xsc; 205 uint32_t status; 206 207 status = RD4(sc, TWI_SR); 208 if (status == 0) 209 return; 210 sc->flags |= status & (TWI_SR_OVRE | TWI_SR_UNRE | TWI_SR_NACK); 211 if (status & TWI_SR_RXRDY) 212 sc->flags |= TWI_SR_RXRDY; 213 if (status & TWI_SR_TXRDY) 214 sc->flags |= TWI_SR_TXRDY; 215 if (status & TWI_SR_TXCOMP) 216 sc->flags |= TWI_SR_TXCOMP; 217 WR4(sc, TWI_IDR, status); 218 wakeup(sc); 219 return; 220} 221 222static int 223at91_twi_wait(struct at91_twi_softc *sc, uint32_t bit) 224{ 225 int err = 0; 226 int counter = 100000; 227 uint32_t sr; 228 229 while (!((sr = RD4(sc, TWI_SR)) & bit) && counter-- > 0) 230 continue; 231 if (counter <= 0) 232 err = EBUSY; 233 else if (sr & TWI_SR_NACK) 234 err = EADDRNOTAVAIL; 235 if (sr & ~bit) 236 printf("status is %x\n", sr); 237 return (err); 238} 239 240static int 241at91_twi_rst_card(device_t dev, u_char speed, u_char addr, u_char *oldaddr) 242{ 243 struct at91_twi_softc *sc; 244 int clk; 245 246 sc = device_get_softc(dev); 247 if (oldaddr) 248 *oldaddr = sc->twi_addr; 249 sc->twi_addr = addr; 250 251 /* 252 * speeds are for 1.5kb/s, 45kb/s and 90kb/s. 253 */ 254 switch (speed) { 255 case IIC_SLOW: 256 clk = 1500; 257 break; 258 259 case IIC_FAST: 260 clk = 45000; 261 break; 262 263 case IIC_UNKNOWN: 264 case IIC_FASTEST: 265 default: 266 clk = 90000; 267 break; 268 } 269 sc->cwgr = TWI_CWGR_CKDIV(1) | TWI_CWGR_CHDIV(TWI_CWGR_DIV(clk)) | 270 TWI_CWGR_CLDIV(TWI_CWGR_DIV(clk)); 271 WR4(sc, TWI_CR, TWI_CR_SWRST); 272 WR4(sc, TWI_CR, TWI_CR_MSEN | TWI_CR_SVDIS); 273 WR4(sc, TWI_CWGR, sc->cwgr); 274 printf("setting cwgr to %#x\n", sc->cwgr); 275 276 return 0; 277} 278 279static int 280at91_twi_callback(device_t dev, int index, caddr_t *data) 281{ 282 int error = 0; 283 284 switch (index) { 285 case IIC_REQUEST_BUS: 286 break; 287 288 case IIC_RELEASE_BUS: 289 break; 290 291 default: 292 error = EINVAL; 293 } 294 295 return (error); 296} 297 298static int 299at91_twi_transfer(device_t dev, struct iic_msg *msgs, uint32_t nmsgs) 300{ 301 struct at91_twi_softc *sc; 302 int i, len, err; 303 uint32_t rdwr; 304 uint8_t *buf; 305 306 sc = device_get_softc(dev); 307 err = 0; 308 AT91_TWI_LOCK(sc); 309 for (i = 0; i < nmsgs; i++) { 310 /* 311 * The linux atmel driver doesn't use the internal device 312 * address feature of twi. A separate i2c message needs to 313 * be written to use this. 314 * See http://lists.arm.linux.org.uk/pipermail/linux-arm-kernel/2004-September/024411.html 315 * for details. Upon reflection, we could use this as an 316 * optimization, but it is unclear the code bloat will 317 * result in faster/better operations. 318 */ 319 rdwr = (msgs[i].flags & IIC_M_RD) ? TWI_MMR_MREAD : 0; 320 WR4(sc, TWI_MMR, TWI_MMR_DADR(msgs[i].slave) | rdwr); 321 len = msgs[i].len; 322 buf = msgs[i].buf; 323 if (len != 0 && buf == NULL) 324 return (EINVAL); 325 WR4(sc, TWI_CR, TWI_CR_START); 326 if (msgs[i].flags & IIC_M_RD) { 327 while (len--) { 328 if (len == 0) 329 WR4(sc, TWI_CR, TWI_CR_STOP); 330 if ((err = at91_twi_wait(sc, TWI_SR_RXRDY))) 331 goto out; 332 *buf++ = RD4(sc, TWI_RHR) & 0xff; 333 } 334 } else { 335 while (len--) { 336 WR4(sc, TWI_THR, *buf++); 337 if (len == 0) 338 WR4(sc, TWI_CR, TWI_CR_STOP); 339 if ((err = at91_twi_wait(sc, TWI_SR_TXRDY))) { 340 printf("Len %d\n", len); 341 goto out; 342 } 343 } 344 } 345 if ((err = at91_twi_wait(sc, TWI_SR_TXCOMP))) 346 break; 347 } 348out:; 349 if (err) { 350 WR4(sc, TWI_CR, TWI_CR_STOP); 351 printf("Err is %d\n", err); 352 } 353 AT91_TWI_UNLOCK(sc); 354 return (err); 355} 356 357static device_method_t at91_twi_methods[] = { 358 /* Device interface */ 359 DEVMETHOD(device_probe, at91_twi_probe), 360 DEVMETHOD(device_attach, at91_twi_attach), 361 DEVMETHOD(device_detach, at91_twi_detach), 362 363 /* iicbus interface */ 364 DEVMETHOD(iicbus_callback, at91_twi_callback), 365 DEVMETHOD(iicbus_reset, at91_twi_rst_card), 366 DEVMETHOD(iicbus_transfer, at91_twi_transfer), 367 { 0, 0 } 368}; 369 370static driver_t at91_twi_driver = { 371 "at91_twi", 372 at91_twi_methods, 373 sizeof(struct at91_twi_softc), 374}; 375 376DRIVER_MODULE(at91_twi, atmelarm, at91_twi_driver, at91_twi_devclass, 0, 0); 377DRIVER_MODULE(iicbus, at91_twi, iicbus_driver, iicbus_devclass, 0, 0); 378