bcm2835_bsc.c revision 276872
1/*- 2 * Copyright (c) 2001 Tsubai Masanari. 3 * Copyright (c) 2012 Oleksandr Tymoshenko <gonzo@freebsd.org> 4 * Copyright (c) 2013 Luiz Otavio O Souza <loos@freebsd.org> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 */ 29#include <sys/cdefs.h> 30__FBSDID("$FreeBSD: stable/10/sys/arm/broadcom/bcm2835/bcm2835_bsc.c 276872 2015-01-09 02:38:12Z loos $"); 31 32#include <sys/param.h> 33#include <sys/systm.h> 34#include <sys/kernel.h> 35#include <sys/lock.h> 36#include <sys/module.h> 37#include <sys/mutex.h> 38#include <sys/bus.h> 39#include <machine/resource.h> 40#include <machine/bus.h> 41#include <sys/rman.h> 42#include <sys/sysctl.h> 43 44#include <dev/iicbus/iicbus.h> 45#include <dev/iicbus/iiconf.h> 46#include <dev/ofw/ofw_bus.h> 47#include <dev/ofw/ofw_bus_subr.h> 48 49#include <arm/broadcom/bcm2835/bcm2835_gpio.h> 50#include <arm/broadcom/bcm2835/bcm2835_bscreg.h> 51#include <arm/broadcom/bcm2835/bcm2835_bscvar.h> 52 53#include "iicbus_if.h" 54 55static void bcm_bsc_intr(void *); 56static int bcm_bsc_detach(device_t); 57 58static void 59bcm_bsc_modifyreg(struct bcm_bsc_softc *sc, uint32_t off, uint32_t mask, 60 uint32_t value) 61{ 62 uint32_t reg; 63 64 mtx_assert(&sc->sc_mtx, MA_OWNED); 65 reg = BCM_BSC_READ(sc, off); 66 reg &= ~mask; 67 reg |= value; 68 BCM_BSC_WRITE(sc, off, reg); 69} 70 71static int 72bcm_bsc_clock_proc(SYSCTL_HANDLER_ARGS) 73{ 74 struct bcm_bsc_softc *sc; 75 uint32_t clk; 76 77 sc = (struct bcm_bsc_softc *)arg1; 78 BCM_BSC_LOCK(sc); 79 clk = BCM_BSC_READ(sc, BCM_BSC_CLOCK); 80 BCM_BSC_UNLOCK(sc); 81 clk &= 0xffff; 82 if (clk == 0) 83 clk = 32768; 84 clk = BCM_BSC_CORE_CLK / clk; 85 86 return (sysctl_handle_int(oidp, &clk, 0, req)); 87} 88 89static int 90bcm_bsc_clkt_proc(SYSCTL_HANDLER_ARGS) 91{ 92 struct bcm_bsc_softc *sc; 93 uint32_t clkt; 94 int error; 95 96 sc = (struct bcm_bsc_softc *)arg1; 97 98 BCM_BSC_LOCK(sc); 99 clkt = BCM_BSC_READ(sc, BCM_BSC_CLKT); 100 BCM_BSC_UNLOCK(sc); 101 clkt &= 0xffff; 102 error = sysctl_handle_int(oidp, &clkt, sizeof(clkt), req); 103 if (error != 0 || req->newptr == NULL) 104 return (error); 105 106 BCM_BSC_LOCK(sc); 107 BCM_BSC_WRITE(sc, BCM_BSC_CLKT, clkt & 0xffff); 108 BCM_BSC_UNLOCK(sc); 109 110 return (0); 111} 112 113static int 114bcm_bsc_fall_proc(SYSCTL_HANDLER_ARGS) 115{ 116 struct bcm_bsc_softc *sc; 117 uint32_t clk, reg; 118 int error; 119 120 sc = (struct bcm_bsc_softc *)arg1; 121 122 BCM_BSC_LOCK(sc); 123 reg = BCM_BSC_READ(sc, BCM_BSC_DELAY); 124 BCM_BSC_UNLOCK(sc); 125 reg >>= 16; 126 error = sysctl_handle_int(oidp, ®, sizeof(reg), req); 127 if (error != 0 || req->newptr == NULL) 128 return (error); 129 130 BCM_BSC_LOCK(sc); 131 clk = BCM_BSC_READ(sc, BCM_BSC_CLOCK); 132 clk = BCM_BSC_CORE_CLK / clk; 133 if (reg > clk / 2) 134 reg = clk / 2 - 1; 135 bcm_bsc_modifyreg(sc, BCM_BSC_DELAY, 0xffff0000, reg << 16); 136 BCM_BSC_UNLOCK(sc); 137 138 return (0); 139} 140 141static int 142bcm_bsc_rise_proc(SYSCTL_HANDLER_ARGS) 143{ 144 struct bcm_bsc_softc *sc; 145 uint32_t clk, reg; 146 int error; 147 148 sc = (struct bcm_bsc_softc *)arg1; 149 150 BCM_BSC_LOCK(sc); 151 reg = BCM_BSC_READ(sc, BCM_BSC_DELAY); 152 BCM_BSC_UNLOCK(sc); 153 reg &= 0xffff; 154 error = sysctl_handle_int(oidp, ®, sizeof(reg), req); 155 if (error != 0 || req->newptr == NULL) 156 return (error); 157 158 BCM_BSC_LOCK(sc); 159 clk = BCM_BSC_READ(sc, BCM_BSC_CLOCK); 160 clk = BCM_BSC_CORE_CLK / clk; 161 if (reg > clk / 2) 162 reg = clk / 2 - 1; 163 bcm_bsc_modifyreg(sc, BCM_BSC_DELAY, 0xffff, reg); 164 BCM_BSC_UNLOCK(sc); 165 166 return (0); 167} 168 169static void 170bcm_bsc_sysctl_init(struct bcm_bsc_softc *sc) 171{ 172 struct sysctl_ctx_list *ctx; 173 struct sysctl_oid *tree_node; 174 struct sysctl_oid_list *tree; 175 176 /* 177 * Add system sysctl tree/handlers. 178 */ 179 ctx = device_get_sysctl_ctx(sc->sc_dev); 180 tree_node = device_get_sysctl_tree(sc->sc_dev); 181 tree = SYSCTL_CHILDREN(tree_node); 182 SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "frequency", 183 CTLFLAG_RW | CTLTYPE_UINT, sc, sizeof(*sc), 184 bcm_bsc_clock_proc, "IU", "I2C BUS clock frequency"); 185 SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "clock_stretch", 186 CTLFLAG_RW | CTLTYPE_UINT, sc, sizeof(*sc), 187 bcm_bsc_clkt_proc, "IU", "I2C BUS clock stretch timeout"); 188 SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "fall_edge_delay", 189 CTLFLAG_RW | CTLTYPE_UINT, sc, sizeof(*sc), 190 bcm_bsc_fall_proc, "IU", "I2C BUS falling edge delay"); 191 SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "rise_edge_delay", 192 CTLFLAG_RW | CTLTYPE_UINT, sc, sizeof(*sc), 193 bcm_bsc_rise_proc, "IU", "I2C BUS rising edge delay"); 194} 195 196static void 197bcm_bsc_reset(struct bcm_bsc_softc *sc) 198{ 199 200 /* Enable the BSC Controller, disable interrupts. */ 201 BCM_BSC_WRITE(sc, BCM_BSC_CTRL, BCM_BSC_CTRL_I2CEN); 202 /* Clear pending interrupts. */ 203 BCM_BSC_WRITE(sc, BCM_BSC_STATUS, BCM_BSC_STATUS_CLKT | 204 BCM_BSC_STATUS_ERR | BCM_BSC_STATUS_DONE); 205 /* Clear the FIFO. */ 206 bcm_bsc_modifyreg(sc, BCM_BSC_CTRL, BCM_BSC_CTRL_CLEAR0, 207 BCM_BSC_CTRL_CLEAR0); 208} 209 210static int 211bcm_bsc_probe(device_t dev) 212{ 213 214 if (!ofw_bus_status_okay(dev)) 215 return (ENXIO); 216 217 if (!ofw_bus_is_compatible(dev, "broadcom,bcm2835-bsc")) 218 return (ENXIO); 219 220 device_set_desc(dev, "BCM2708/2835 BSC controller"); 221 222 return (BUS_PROBE_DEFAULT); 223} 224 225static int 226bcm_bsc_attach(device_t dev) 227{ 228 struct bcm_bsc_softc *sc; 229 unsigned long start; 230 device_t gpio; 231 int i, rid; 232 233 sc = device_get_softc(dev); 234 sc->sc_dev = dev; 235 236 rid = 0; 237 sc->sc_mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, 238 RF_ACTIVE); 239 if (!sc->sc_mem_res) { 240 device_printf(dev, "cannot allocate memory window\n"); 241 return (ENXIO); 242 } 243 244 sc->sc_bst = rman_get_bustag(sc->sc_mem_res); 245 sc->sc_bsh = rman_get_bushandle(sc->sc_mem_res); 246 247 /* Check the unit we are attaching by its base address. */ 248 start = rman_get_start(sc->sc_mem_res); 249 for (i = 0; i < nitems(bcm_bsc_pins); i++) { 250 if (bcm_bsc_pins[i].start == start) 251 break; 252 } 253 if (i == nitems(bcm_bsc_pins)) { 254 device_printf(dev, "only bsc0 and bsc1 are supported\n"); 255 return (ENXIO); 256 } 257 258 /* 259 * Configure the GPIO pins to ALT0 function to enable BSC control 260 * over the pins. 261 */ 262 gpio = devclass_get_device(devclass_find("gpio"), 0); 263 if (!gpio) { 264 device_printf(dev, "cannot find gpio0\n"); 265 return (ENXIO); 266 } 267 bcm_gpio_set_alternate(gpio, bcm_bsc_pins[i].sda, BCM_GPIO_ALT0); 268 bcm_gpio_set_alternate(gpio, bcm_bsc_pins[i].scl, BCM_GPIO_ALT0); 269 270 rid = 0; 271 sc->sc_irq_res = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid, 272 RF_ACTIVE | RF_SHAREABLE); 273 if (!sc->sc_irq_res) { 274 bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->sc_mem_res); 275 device_printf(dev, "cannot allocate interrupt\n"); 276 return (ENXIO); 277 } 278 279 /* Hook up our interrupt handler. */ 280 if (bus_setup_intr(dev, sc->sc_irq_res, INTR_TYPE_MISC | INTR_MPSAFE, 281 NULL, bcm_bsc_intr, sc, &sc->sc_intrhand)) { 282 bus_release_resource(dev, SYS_RES_IRQ, 0, sc->sc_irq_res); 283 bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->sc_mem_res); 284 device_printf(dev, "cannot setup the interrupt handler\n"); 285 return (ENXIO); 286 } 287 288 mtx_init(&sc->sc_mtx, "bcm_bsc", NULL, MTX_DEF); 289 290 bcm_bsc_sysctl_init(sc); 291 292 /* Enable the BSC controller. Flush the FIFO. */ 293 BCM_BSC_LOCK(sc); 294 bcm_bsc_reset(sc); 295 BCM_BSC_UNLOCK(sc); 296 297 sc->sc_iicbus = device_add_child(dev, "iicbus", -1); 298 if (sc->sc_iicbus == NULL) { 299 bcm_bsc_detach(dev); 300 return (ENXIO); 301 } 302 303 return (bus_generic_attach(dev)); 304} 305 306static int 307bcm_bsc_detach(device_t dev) 308{ 309 struct bcm_bsc_softc *sc; 310 311 bus_generic_detach(dev); 312 313 sc = device_get_softc(dev); 314 mtx_destroy(&sc->sc_mtx); 315 if (sc->sc_intrhand) 316 bus_teardown_intr(dev, sc->sc_irq_res, sc->sc_intrhand); 317 if (sc->sc_irq_res) 318 bus_release_resource(dev, SYS_RES_IRQ, 0, sc->sc_irq_res); 319 if (sc->sc_mem_res) 320 bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->sc_mem_res); 321 322 return (0); 323} 324 325static void 326bcm_bsc_intr(void *arg) 327{ 328 struct bcm_bsc_softc *sc; 329 uint32_t status; 330 331 sc = (struct bcm_bsc_softc *)arg; 332 333 BCM_BSC_LOCK(sc); 334 335 /* The I2C interrupt is shared among all the BSC controllers. */ 336 if ((sc->sc_flags & BCM_I2C_BUSY) == 0) { 337 BCM_BSC_UNLOCK(sc); 338 return; 339 } 340 341 status = BCM_BSC_READ(sc, BCM_BSC_STATUS); 342 343 /* Check for errors. */ 344 if (status & (BCM_BSC_STATUS_CLKT | BCM_BSC_STATUS_ERR)) { 345 /* Disable interrupts. */ 346 bcm_bsc_reset(sc); 347 sc->sc_flags |= BCM_I2C_ERROR; 348 wakeup(sc->sc_dev); 349 BCM_BSC_UNLOCK(sc); 350 return; 351 } 352 353 if (sc->sc_flags & BCM_I2C_READ) { 354 while (sc->sc_resid > 0 && (status & BCM_BSC_STATUS_RXD)) { 355 *sc->sc_data++ = BCM_BSC_READ(sc, BCM_BSC_DATA); 356 sc->sc_resid--; 357 status = BCM_BSC_READ(sc, BCM_BSC_STATUS); 358 } 359 } else { 360 while (sc->sc_resid > 0 && (status & BCM_BSC_STATUS_TXD)) { 361 BCM_BSC_WRITE(sc, BCM_BSC_DATA, *sc->sc_data++); 362 sc->sc_resid--; 363 status = BCM_BSC_READ(sc, BCM_BSC_STATUS); 364 } 365 } 366 367 if (status & BCM_BSC_STATUS_DONE) { 368 /* Disable interrupts. */ 369 bcm_bsc_reset(sc); 370 wakeup(sc->sc_dev); 371 } 372 373 BCM_BSC_UNLOCK(sc); 374} 375 376static int 377bcm_bsc_transfer(device_t dev, struct iic_msg *msgs, uint32_t nmsgs) 378{ 379 struct bcm_bsc_softc *sc; 380 uint32_t intr, read, status; 381 int i, err; 382 383 sc = device_get_softc(dev); 384 BCM_BSC_LOCK(sc); 385 386 /* If the controller is busy wait until it is available. */ 387 while (sc->sc_flags & BCM_I2C_BUSY) 388 mtx_sleep(dev, &sc->sc_mtx, 0, "bscbusw", 0); 389 390 /* Now we have control over the BSC controller. */ 391 sc->sc_flags = BCM_I2C_BUSY; 392 393 /* Clear the FIFO and the pending interrupts. */ 394 bcm_bsc_reset(sc); 395 396 err = 0; 397 for (i = 0; i < nmsgs; i++) { 398 399 /* Write the slave address. */ 400 BCM_BSC_WRITE(sc, BCM_BSC_SLAVE, msgs[i].slave >> 1); 401 402 /* Write the data length. */ 403 BCM_BSC_WRITE(sc, BCM_BSC_DLEN, msgs[i].len); 404 405 sc->sc_data = msgs[i].buf; 406 sc->sc_resid = msgs[i].len; 407 if ((msgs[i].flags & IIC_M_RD) == 0) { 408 /* Fill up the TX FIFO. */ 409 status = BCM_BSC_READ(sc, BCM_BSC_STATUS); 410 while (sc->sc_resid > 0 && 411 (status & BCM_BSC_STATUS_TXD)) { 412 BCM_BSC_WRITE(sc, BCM_BSC_DATA, *sc->sc_data); 413 sc->sc_data++; 414 sc->sc_resid--; 415 status = BCM_BSC_READ(sc, BCM_BSC_STATUS); 416 } 417 read = 0; 418 intr = BCM_BSC_CTRL_INTT; 419 sc->sc_flags &= ~BCM_I2C_READ; 420 } else { 421 sc->sc_flags |= BCM_I2C_READ; 422 read = BCM_BSC_CTRL_READ; 423 intr = BCM_BSC_CTRL_INTR; 424 } 425 intr |= BCM_BSC_CTRL_INTD; 426 427 /* Start the transfer. */ 428 BCM_BSC_WRITE(sc, BCM_BSC_CTRL, BCM_BSC_CTRL_I2CEN | 429 BCM_BSC_CTRL_ST | read | intr); 430 431 /* Wait for the transaction to complete. */ 432 err = mtx_sleep(dev, &sc->sc_mtx, 0, "bsciow", hz); 433 434 /* Check for errors. */ 435 if (err == 0 && (sc->sc_flags & BCM_I2C_ERROR)) 436 err = EIO; 437 if (err != 0) 438 break; 439 } 440 441 /* Clean the controller flags. */ 442 sc->sc_flags = 0; 443 444 /* Wake up the threads waiting for bus. */ 445 wakeup(dev); 446 447 BCM_BSC_UNLOCK(sc); 448 449 return (err); 450} 451 452static int 453bcm_bsc_iicbus_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr) 454{ 455 struct bcm_bsc_softc *sc; 456 uint32_t busfreq; 457 458 sc = device_get_softc(dev); 459 BCM_BSC_LOCK(sc); 460 bcm_bsc_reset(sc); 461 if (sc->sc_iicbus == NULL) 462 busfreq = 100000; 463 else 464 busfreq = IICBUS_GET_FREQUENCY(sc->sc_iicbus, speed); 465 BCM_BSC_WRITE(sc, BCM_BSC_CLOCK, BCM_BSC_CORE_CLK / busfreq); 466 BCM_BSC_UNLOCK(sc); 467 468 return (IIC_ENOADDR); 469} 470 471static phandle_t 472bcm_bsc_get_node(device_t bus, device_t dev) 473{ 474 475 /* We only have one child, the I2C bus, which needs our own node. */ 476 return (ofw_bus_get_node(bus)); 477} 478 479static device_method_t bcm_bsc_methods[] = { 480 /* Device interface */ 481 DEVMETHOD(device_probe, bcm_bsc_probe), 482 DEVMETHOD(device_attach, bcm_bsc_attach), 483 DEVMETHOD(device_detach, bcm_bsc_detach), 484 485 /* iicbus interface */ 486 DEVMETHOD(iicbus_reset, bcm_bsc_iicbus_reset), 487 DEVMETHOD(iicbus_callback, iicbus_null_callback), 488 DEVMETHOD(iicbus_transfer, bcm_bsc_transfer), 489 490 /* ofw_bus interface */ 491 DEVMETHOD(ofw_bus_get_node, bcm_bsc_get_node), 492 493 DEVMETHOD_END 494}; 495 496static devclass_t bcm_bsc_devclass; 497 498static driver_t bcm_bsc_driver = { 499 "iichb", 500 bcm_bsc_methods, 501 sizeof(struct bcm_bsc_softc), 502}; 503 504DRIVER_MODULE(iicbus, bcm2835_bsc, iicbus_driver, iicbus_devclass, 0, 0); 505DRIVER_MODULE(bcm2835_bsc, simplebus, bcm_bsc_driver, bcm_bsc_devclass, 0, 0); 506