freebsd-dev/sys/arm/at91/at91_twi.c

404 lines
9.6 KiB
C

/*-
* Copyright (c) 2006 M. Warner Losh. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mbuf.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/rman.h>
#include <machine/bus.h>
#include <arm/at91/at91_twireg.h>
#include <arm/at91/at91var.h>
#include <dev/iicbus/iiconf.h>
#include <dev/iicbus/iicbus.h>
#include "iicbus_if.h"
#define TWI_SLOW_CLOCK 1500
#define TWI_FAST_CLOCK 45000
#define TWI_FASTEST_CLOCK 90000
struct at91_twi_softc
{
device_t dev; /* Myself */
void *intrhand; /* Interrupt handle */
struct resource *irq_res; /* IRQ resource */
struct resource *mem_res; /* Memory resource */
struct mtx sc_mtx; /* basically a perimeter lock */
volatile uint32_t flags;
uint32_t cwgr;
int sc_started;
int twi_addr;
device_t iicbus;
};
static inline uint32_t
RD4(struct at91_twi_softc *sc, bus_size_t off)
{
return bus_read_4(sc->mem_res, off);
}
static inline void
WR4(struct at91_twi_softc *sc, bus_size_t off, uint32_t val)
{
bus_write_4(sc->mem_res, off, val);
}
#define AT91_TWI_LOCK(_sc) mtx_lock(&(_sc)->sc_mtx)
#define AT91_TWI_UNLOCK(_sc) mtx_unlock(&(_sc)->sc_mtx)
#define AT91_TWI_LOCK_INIT(_sc) \
mtx_init(&_sc->sc_mtx, device_get_nameunit(_sc->dev), \
"twi", MTX_DEF)
#define AT91_TWI_LOCK_DESTROY(_sc) mtx_destroy(&_sc->sc_mtx);
#define AT91_TWI_ASSERT_LOCKED(_sc) mtx_assert(&_sc->sc_mtx, MA_OWNED);
#define AT91_TWI_ASSERT_UNLOCKED(_sc) mtx_assert(&_sc->sc_mtx, MA_NOTOWNED);
#define TWI_DEF_CLK 100000
static devclass_t at91_twi_devclass;
/* bus entry points */
static int at91_twi_probe(device_t dev);
static int at91_twi_attach(device_t dev);
static int at91_twi_detach(device_t dev);
static void at91_twi_intr(void *);
/* helper routines */
static int at91_twi_activate(device_t dev);
static void at91_twi_deactivate(device_t dev);
static int
at91_twi_probe(device_t dev)
{
device_set_desc(dev, "TWI");
return (0);
}
static int
at91_twi_attach(device_t dev)
{
struct at91_twi_softc *sc = device_get_softc(dev);
int err;
sc->dev = dev;
err = at91_twi_activate(dev);
if (err)
goto out;
AT91_TWI_LOCK_INIT(sc);
/*
* Activate the interrupt
*/
err = bus_setup_intr(dev, sc->irq_res, INTR_TYPE_MISC | INTR_MPSAFE,
NULL, at91_twi_intr, sc, &sc->intrhand);
if (err) {
AT91_TWI_LOCK_DESTROY(sc);
goto out;
}
sc->cwgr = TWI_CWGR_CKDIV(8 * at91_master_clock / TWI_FASTEST_CLOCK) |
TWI_CWGR_CHDIV(TWI_CWGR_DIV(TWI_DEF_CLK)) |
TWI_CWGR_CLDIV(TWI_CWGR_DIV(TWI_DEF_CLK));
WR4(sc, TWI_CR, TWI_CR_SWRST);
WR4(sc, TWI_CR, TWI_CR_MSEN | TWI_CR_SVDIS);
WR4(sc, TWI_CWGR, sc->cwgr);
if ((sc->iicbus = device_add_child(dev, "iicbus", -1)) == NULL)
device_printf(dev, "could not allocate iicbus instance\n");
/* probe and attach the iicbus */
bus_generic_attach(dev);
out:
if (err)
at91_twi_deactivate(dev);
return (err);
}
static int
at91_twi_detach(device_t dev)
{
struct at91_twi_softc *sc;
int rv;
sc = device_get_softc(dev);
at91_twi_deactivate(dev);
if (sc->iicbus && (rv = device_delete_child(dev, sc->iicbus)) != 0)
return (rv);
AT91_TWI_LOCK_DESTROY(sc);
return (0);
}
static int
at91_twi_activate(device_t dev)
{
struct at91_twi_softc *sc;
int rid;
sc = device_get_softc(dev);
rid = 0;
sc->mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
RF_ACTIVE);
if (sc->mem_res == NULL)
goto errout;
rid = 0;
sc->irq_res = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
RF_ACTIVE);
if (sc->irq_res == NULL)
goto errout;
return (0);
errout:
at91_twi_deactivate(dev);
return (ENOMEM);
}
static void
at91_twi_deactivate(device_t dev)
{
struct at91_twi_softc *sc;
sc = device_get_softc(dev);
if (sc->intrhand)
bus_teardown_intr(dev, sc->irq_res, sc->intrhand);
sc->intrhand = 0;
bus_generic_detach(sc->dev);
if (sc->mem_res)
bus_release_resource(dev, SYS_RES_MEMORY,
rman_get_rid(sc->mem_res), sc->mem_res);
sc->mem_res = 0;
if (sc->irq_res)
bus_release_resource(dev, SYS_RES_IRQ,
rman_get_rid(sc->irq_res), sc->irq_res);
sc->irq_res = 0;
return;
}
static void
at91_twi_intr(void *xsc)
{
struct at91_twi_softc *sc = xsc;
uint32_t status;
status = RD4(sc, TWI_SR);
if (status == 0)
return;
AT91_TWI_LOCK(sc);
sc->flags |= status & (TWI_SR_OVRE | TWI_SR_UNRE | TWI_SR_NACK);
if (status & TWI_SR_RXRDY)
sc->flags |= TWI_SR_RXRDY;
if (status & TWI_SR_TXRDY)
sc->flags |= TWI_SR_TXRDY;
if (status & TWI_SR_TXCOMP)
sc->flags |= TWI_SR_TXCOMP;
WR4(sc, TWI_IDR, status);
wakeup(sc);
AT91_TWI_UNLOCK(sc);
return;
}
static int
at91_twi_wait(struct at91_twi_softc *sc, uint32_t bit)
{
int err = 0;
int counter = 100000;
uint32_t sr;
AT91_TWI_ASSERT_LOCKED(sc);
while (!((sr = RD4(sc, TWI_SR)) & bit) && counter-- > 0 &&
!(sr & TWI_SR_NACK))
continue;
if (counter <= 0)
err = EBUSY;
else if (sr & TWI_SR_NACK)
err = ENXIO; // iic nack convention
return (err);
}
static int
at91_twi_rst_card(device_t dev, u_char speed, u_char addr, u_char *oldaddr)
{
struct at91_twi_softc *sc;
int clk;
sc = device_get_softc(dev);
AT91_TWI_LOCK(sc);
if (oldaddr)
*oldaddr = sc->twi_addr;
sc->twi_addr = addr;
/*
* speeds are for 1.5kb/s, 45kb/s and 90kb/s.
*/
switch (speed) {
case IIC_SLOW:
clk = TWI_SLOW_CLOCK;
break;
case IIC_FAST:
clk = TWI_FAST_CLOCK;
break;
case IIC_UNKNOWN:
case IIC_FASTEST:
default:
clk = TWI_FASTEST_CLOCK;
break;
}
sc->cwgr = TWI_CWGR_CKDIV(1) | TWI_CWGR_CHDIV(TWI_CWGR_DIV(clk)) |
TWI_CWGR_CLDIV(TWI_CWGR_DIV(clk));
WR4(sc, TWI_CR, TWI_CR_SWRST);
WR4(sc, TWI_CR, TWI_CR_MSEN | TWI_CR_SVDIS);
WR4(sc, TWI_CWGR, sc->cwgr);
AT91_TWI_UNLOCK(sc);
return 0;
}
static int
at91_twi_callback(device_t dev, int index, caddr_t data)
{
int error = 0;
switch (index) {
case IIC_REQUEST_BUS:
break;
case IIC_RELEASE_BUS:
break;
default:
error = EINVAL;
}
return (error);
}
static int
at91_twi_transfer(device_t dev, struct iic_msg *msgs, uint32_t nmsgs)
{
struct at91_twi_softc *sc;
int i, len, err;
uint32_t rdwr;
uint8_t *buf;
uint32_t sr;
sc = device_get_softc(dev);
err = 0;
AT91_TWI_LOCK(sc);
for (i = 0; i < nmsgs; i++) {
/*
* The linux atmel driver doesn't use the internal device
* address feature of twi. A separate i2c message needs to
* be written to use this.
* See http://lists.arm.linux.org.uk/pipermail/linux-arm-kernel/2004-September/024411.html
* for details. Upon reflection, we could use this as an
* optimization, but it is unclear the code bloat will
* result in faster/better operations.
*/
rdwr = (msgs[i].flags & IIC_M_RD) ? TWI_MMR_MREAD : 0;
WR4(sc, TWI_MMR, TWI_MMR_DADR(msgs[i].slave) | rdwr);
len = msgs[i].len;
buf = msgs[i].buf;
/* zero byte transfers aren't allowed */
if (len == 0 || buf == NULL) {
err = EINVAL;
goto out;
}
if (len == 1 && msgs[i].flags & IIC_M_RD)
WR4(sc, TWI_CR, TWI_CR_START | TWI_CR_STOP);
else
WR4(sc, TWI_CR, TWI_CR_START);
if (msgs[i].flags & IIC_M_RD) {
sr = RD4(sc, TWI_SR);
while (!(sr & TWI_SR_TXCOMP)) {
if ((sr = RD4(sc, TWI_SR)) & TWI_SR_RXRDY) {
len--;
*buf++ = RD4(sc, TWI_RHR) & 0xff;
if (len == 1)
WR4(sc, TWI_CR, TWI_CR_STOP);
}
}
if (len > 0 || (sr & TWI_SR_NACK)) {
err = ENXIO; // iic nack convention
goto out;
}
} else {
while (len--) {
if ((err = at91_twi_wait(sc, TWI_SR_TXRDY)))
goto out;
WR4(sc, TWI_THR, *buf++);
}
WR4(sc, TWI_CR, TWI_CR_STOP);
}
if ((err = at91_twi_wait(sc, TWI_SR_TXCOMP)))
break;
}
out:
if (err) {
WR4(sc, TWI_CR, TWI_CR_SWRST);
WR4(sc, TWI_CR, TWI_CR_MSEN | TWI_CR_SVDIS);
WR4(sc, TWI_CWGR, sc->cwgr);
}
AT91_TWI_UNLOCK(sc);
return (err);
}
static device_method_t at91_twi_methods[] = {
/* Device interface */
DEVMETHOD(device_probe, at91_twi_probe),
DEVMETHOD(device_attach, at91_twi_attach),
DEVMETHOD(device_detach, at91_twi_detach),
/* iicbus interface */
DEVMETHOD(iicbus_callback, at91_twi_callback),
DEVMETHOD(iicbus_reset, at91_twi_rst_card),
DEVMETHOD(iicbus_transfer, at91_twi_transfer),
DEVMETHOD_END
};
static driver_t at91_twi_driver = {
"at91_twi",
at91_twi_methods,
sizeof(struct at91_twi_softc),
};
DRIVER_MODULE(at91_twi, atmelarm, at91_twi_driver, at91_twi_devclass, NULL,
NULL);
DRIVER_MODULE(iicbus, at91_twi, iicbus_driver, iicbus_devclass, NULL, NULL);
MODULE_DEPEND(at91_twi, iicbus, 1, 1, 1);