freebsd-dev/sys/arm/at91/at91_st.c
Olivier Houchard d5d776c16b Resurrect Skyeye support :
Add a new option, SKYEYE_WORKAROUNDS, which as the name suggests adds
workarounds for things skyeye doesn't simulate. Specifically :
- Use USART0 instead of DBGU as the console, make it not use DMA, and           manually provoke an interrupt when we're done in the transmit function.
- Skyeye maintains an internal counter for clock, but apparently there's
no way to access it, so hack the timecounter code to return a value which
is increased at every clock interrupts. This is gross, but I didn't find a
better way to implement timecounters without hacking Skyeye to get the
counter value.
- Force the write-back of PTEs once we're done writing them, even if they
are supposed to be write-through. I don't know why I have to do that.
2006-05-13 23:41:16 +00:00

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/*-
* Copyright (c) 2005 Olivier Houchard. 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 THE AUTHOR ``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 THE AUTHOR 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/kernel.h>
#include <sys/module.h>
#include <sys/time.h>
#include <sys/bus.h>
#include <sys/resource.h>
#include <sys/rman.h>
#include <sys/timetc.h>
#include <machine/bus.h>
#include <machine/cpu.h>
#include <machine/cpufunc.h>
#include <machine/resource.h>
#include <machine/frame.h>
#include <machine/intr.h>
#include <arm/at91/at91rm92reg.h>
#include <arm/at91/at91var.h>
#include <arm/at91/at91_streg.h>
static struct at91st_softc {
bus_space_tag_t sc_st;
bus_space_handle_t sc_sh;
device_t dev;
} *timer_softc;
#define RD4(off) \
bus_space_read_4(timer_softc->sc_st, timer_softc->sc_sh, (off))
#define WR4(off, val) \
bus_space_write_4(timer_softc->sc_st, timer_softc->sc_sh, (off), (val))
static inline int
st_crtr(void)
{
int cur1, cur2;
do {
cur1 = RD4(ST_CRTR);
cur2 = RD4(ST_CRTR);
} while (cur1 != cur2);
return (cur1);
}
static unsigned at91st_get_timecount(struct timecounter *tc);
static struct timecounter at91st_timecounter = {
at91st_get_timecount, /* get_timecount */
NULL, /* no poll_pps */
#ifdef SKYEYE_WORKAROUNDS
0xffffffffu, /* counter_mask */
#else
0xfffffu, /* counter_mask */
#endif
32768, /* frequency */
"AT91RM9200 timer", /* name */
0 /* quality */
};
static int
at91st_probe(device_t dev)
{
device_set_desc(dev, "ST");
return (0);
}
static int
at91st_attach(device_t dev)
{
struct at91_softc *sc = device_get_softc(device_get_parent(dev));
timer_softc = device_get_softc(dev);
timer_softc->sc_st = sc->sc_st;
timer_softc->dev = dev;
if (bus_space_subregion(sc->sc_st, sc->sc_sh, AT91RM92_ST_BASE,
AT91RM92_ST_SIZE, &timer_softc->sc_sh) != 0)
panic("couldn't subregion timer registers");
/*
* Real time counter increments every clock cycle, need to set before
* initializing clocks so that DELAY works.
*/
WR4(ST_RTMR, 1);
/* Disable all interrupts */
WR4(ST_IDR, 0xffffffff);
return (0);
}
static device_method_t at91st_methods[] = {
DEVMETHOD(device_probe, at91st_probe),
DEVMETHOD(device_attach, at91st_attach),
{0, 0},
};
static driver_t at91st_driver = {
"at91_st",
at91st_methods,
sizeof(struct at91st_softc),
};
static devclass_t at91st_devclass;
DRIVER_MODULE(at91_st, atmelarm, at91st_driver, at91st_devclass, 0, 0);
#ifdef SKYEYE_WORKAROUNDS
static unsigned long tot_count = 0;
#endif
static unsigned
at91st_get_timecount(struct timecounter *tc)
{
#ifdef SKYEYE_WORKAROUNDS
return (tot_count);
#else
return (st_crtr());
#endif
}
static void
clock_intr(void *arg)
{
struct trapframe *fp = arg;
/* The interrupt is shared, so we have to make sure it's for us. */
if (RD4(ST_SR) & ST_SR_PITS) {
#ifdef SKYEYE_WORKAROUNDS
tot_count += 32768 / hz;
#endif
hardclock(TRAPF_USERMODE(fp), TRAPF_PC(fp));
}
}
void
cpu_initclocks(void)
{
int rel_value;
struct resource *irq;
int rid = 0;
void *ih;
device_t dev = timer_softc->dev;
if (32768 % hz) {
printf("Cannot get %d Hz clock; using 128Hz\n", hz);
hz = 128;
}
rel_value = 32768 / hz;
/* Disable all interrupts.<2E>*/
WR4(ST_IDR, 0xffffffff);
/* The system timer shares the system irq (1) */
irq = bus_alloc_resource(dev, SYS_RES_IRQ, &rid, 1, 1, 1,
RF_ACTIVE | RF_SHAREABLE);
if (!irq)
panic("Unable to allocate irq for the system timer");
else
bus_setup_intr(dev, irq, INTR_TYPE_CLK | INTR_FAST,
clock_intr, NULL, &ih);
WR4(ST_PIMR, rel_value);
/* Enable PITS interrupts. */
WR4(ST_IER, ST_SR_PITS);
tc_init(&at91st_timecounter);
}
void
DELAY(int n)
{
uint32_t start, end, cur;
start = st_crtr();
n = (n * 1000) / 32768;
if (n <= 0)
n = 1;
end = (start + n) & ST_CRTR_MASK;
cur = start;
if (start > end) {
while (cur >= start || cur < end)
cur = st_crtr();
} else {
while (cur < end)
cur = st_crtr();
}
}
void
cpu_reset(void)
{
/*
* Reset the CPU by programmig the watchdog timer to reset the
* CPU after 128 'slow' clocks, or about ~4ms. Loop until
* the reset happens for safety.
*/
WR4(ST_WDMR, ST_WDMR_RSTEN | 2);
WR4(ST_CR, ST_CR_WDRST);
while (1)
continue;
}
void
cpu_startprofclock(void)
{
}
void
cpu_stopprofclock(void)
{
}