2 * Copyright (c) 2011 The FreeBSD Foundation
5 * Developed by Ben Gray <ben.r.gray@gmail.com>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
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 * 3. The name of the company nor the name of the author may be used to
16 * endorse or promote products derived from this software without specific
17 * prior written permission.
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * The ARM Cortex-A9 core can support a global timer plus a private and
34 * watchdog timer per core. This driver reserves memory and interrupt
35 * resources for accessing both timer register sets, these resources are
36 * stored globally and used to setup the timecount and eventtimer.
38 * The timecount timer uses the global 64-bit counter, whereas the
39 * per-CPU eventtimer uses the private 32-bit counters.
42 * REF: ARM Cortex-A9 MPCore, Technical Reference Manual (rev. r2p2)
45 #include <sys/cdefs.h>
46 __FBSDID("$FreeBSD$");
48 #include <sys/param.h>
49 #include <sys/systm.h>
51 #include <sys/kernel.h>
52 #include <sys/module.h>
53 #include <sys/malloc.h>
55 #include <sys/timeet.h>
56 #include <sys/timetc.h>
57 #include <sys/watchdog.h>
58 #include <machine/bus.h>
59 #include <machine/cpu.h>
60 #include <machine/frame.h>
61 #include <machine/intr.h>
63 #include <dev/fdt/fdt_common.h>
64 #include <dev/ofw/openfirm.h>
65 #include <dev/ofw/ofw_bus.h>
66 #include <dev/ofw/ofw_bus_subr.h>
68 #include <machine/bus.h>
69 #include <machine/fdt.h>
71 /* Private (per-CPU) timer register map */
72 #define PRV_TIMER_LOAD 0x0000
73 #define PRV_TIMER_COUNT 0x0004
74 #define PRV_TIMER_CTRL 0x0008
75 #define PRV_TIMER_INTR 0x000C
77 #define PRV_TIMER_CTR_PRESCALER_SHIFT 8
78 #define PRV_TIMER_CTRL_IRQ_ENABLE (1UL << 2)
79 #define PRV_TIMER_CTRL_AUTO_RELOAD (1UL << 1)
80 #define PRV_TIMER_CTRL_TIMER_ENABLE (1UL << 0)
82 #define PRV_TIMER_INTR_EVENT (1UL << 0)
84 /* Global timer register map */
85 #define GBL_TIMER_COUNT_LOW 0x0000
86 #define GBL_TIMER_COUNT_HIGH 0x0004
87 #define GBL_TIMER_CTRL 0x0008
88 #define GBL_TIMER_INTR 0x000C
90 #define GBL_TIMER_CTR_PRESCALER_SHIFT 8
91 #define GBL_TIMER_CTRL_AUTO_INC (1UL << 3)
92 #define GBL_TIMER_CTRL_IRQ_ENABLE (1UL << 2)
93 #define GBL_TIMER_CTRL_COMP_ENABLE (1UL << 1)
94 #define GBL_TIMER_CTRL_TIMER_ENABLE (1UL << 0)
96 #define GBL_TIMER_INTR_EVENT (1UL << 0)
98 struct arm_tmr_softc {
99 struct resource * tmr_res[4];
100 bus_space_tag_t prv_bst;
101 bus_space_tag_t gbl_bst;
102 bus_space_handle_t prv_bsh;
103 bus_space_handle_t gbl_bsh;
105 struct eventtimer et;
108 static struct resource_spec arm_tmr_spec[] = {
109 { SYS_RES_MEMORY, 0, RF_ACTIVE }, /* Global registers */
110 { SYS_RES_IRQ, 0, RF_ACTIVE }, /* Global timer interrupt (unused) */
111 { SYS_RES_MEMORY, 1, RF_ACTIVE }, /* Private (per-CPU) registers */
112 { SYS_RES_IRQ, 1, RF_ACTIVE }, /* Private timer interrupt */
116 static struct arm_tmr_softc *arm_tmr_sc = NULL;
118 uint32_t platform_arm_tmr_freq = 0;
120 #define tmr_prv_read_4(reg) \
121 bus_space_read_4(arm_tmr_sc->prv_bst, arm_tmr_sc->prv_bsh, reg)
122 #define tmr_prv_write_4(reg, val) \
123 bus_space_write_4(arm_tmr_sc->prv_bst, arm_tmr_sc->prv_bsh, reg, val)
124 #define tmr_gbl_read_4(reg) \
125 bus_space_read_4(arm_tmr_sc->gbl_bst, arm_tmr_sc->gbl_bsh, reg)
126 #define tmr_gbl_write_4(reg, val) \
127 bus_space_write_4(arm_tmr_sc->gbl_bst, arm_tmr_sc->gbl_bsh, reg, val)
130 static timecounter_get_t arm_tmr_get_timecount;
132 static struct timecounter arm_tmr_timecount = {
133 .tc_name = "ARM MPCore Timecounter",
134 .tc_get_timecount = arm_tmr_get_timecount,
136 .tc_counter_mask = ~0u,
142 * arm_tmr_get_timecount - reads the timecount (global) timer
143 * @tc: pointer to arm_tmr_timecount struct
145 * We only read the lower 32-bits, the timecount stuff only uses 32-bits
146 * so (for now?) ignore the upper 32-bits.
149 * The lower 32-bits of the counter.
152 arm_tmr_get_timecount(struct timecounter *tc)
154 return (tmr_gbl_read_4(GBL_TIMER_COUNT_LOW));
158 * arm_tmr_start - starts the eventtimer (private) timer
159 * @et: pointer to eventtimer struct
160 * @first: the number of seconds and fractional sections to trigger in
161 * @period: the period (in seconds and fractional sections) to set
163 * If the eventtimer is required to be in oneshot mode, period will be
164 * NULL and first will point to the time to trigger. If in periodic mode
165 * period will contain the time period and first may optionally contain
166 * the time for the first period.
172 arm_tmr_start(struct eventtimer *et, sbintime_t first, sbintime_t period)
174 uint32_t load, count;
177 ctrl = PRV_TIMER_CTRL_IRQ_ENABLE | PRV_TIMER_CTRL_TIMER_ENABLE;
180 load = ((uint32_t)et->et_frequency * period) >> 32;
181 ctrl |= PRV_TIMER_CTRL_AUTO_RELOAD;
186 count = ((uint32_t)et->et_frequency * first) >> 32;
190 tmr_prv_write_4(PRV_TIMER_LOAD, load);
191 tmr_prv_write_4(PRV_TIMER_COUNT, count);
193 tmr_prv_write_4(PRV_TIMER_CTRL, ctrl);
198 * arm_tmr_stop - stops the eventtimer (private) timer
199 * @et: pointer to eventtimer struct
201 * Simply stops the private timer by clearing all bits in the ctrl register.
207 arm_tmr_stop(struct eventtimer *et)
209 tmr_prv_write_4(PRV_TIMER_CTRL, 0);
214 * arm_tmr_intr - ISR for the eventtimer (private) timer
215 * @arg: pointer to arm_tmr_softc struct
217 * Clears the event register and then calls the eventtimer callback.
220 * Always returns FILTER_HANDLED
223 arm_tmr_intr(void *arg)
225 struct arm_tmr_softc *sc = (struct arm_tmr_softc *)arg;
227 tmr_prv_write_4(PRV_TIMER_INTR, PRV_TIMER_INTR_EVENT);
229 if (sc->et.et_active)
230 sc->et.et_event_cb(&sc->et, sc->et.et_arg);
232 return (FILTER_HANDLED);
239 * arm_tmr_probe - timer probe routine
242 * The probe function returns success when probed with the fdt compatible
243 * string set to "arm,mpcore-timers".
246 * BUS_PROBE_DEFAULT if the fdt device is compatible, otherwise ENXIO.
249 arm_tmr_probe(device_t dev)
251 if (!ofw_bus_is_compatible(dev, "arm,mpcore-timers"))
254 device_set_desc(dev, "ARM Generic MPCore Timers");
255 return (BUS_PROBE_DEFAULT);
259 * arm_tmr_attach - attaches the timer to the simplebus
262 * Reserves memory and interrupt resources, stores the softc structure
263 * globally and registers both the timecount and eventtimer objects.
266 * Zero on sucess or ENXIO if an error occuried.
269 arm_tmr_attach(device_t dev)
271 struct arm_tmr_softc *sc = device_get_softc(dev);
279 if (platform_arm_tmr_freq != 0)
280 sc->clkfreq = platform_arm_tmr_freq;
282 /* Get the base clock frequency */
283 node = ofw_bus_get_node(dev);
284 if ((OF_getprop(node, "clock-frequency", &clock,
285 sizeof(clock))) <= 0) {
286 device_printf(dev, "missing clock-frequency attribute in FDT\n");
289 sc->clkfreq = fdt32_to_cpu(clock);
293 if (bus_alloc_resources(dev, arm_tmr_spec, sc->tmr_res)) {
294 device_printf(dev, "could not allocate resources\n");
298 /* Global timer interface */
299 sc->gbl_bst = rman_get_bustag(sc->tmr_res[0]);
300 sc->gbl_bsh = rman_get_bushandle(sc->tmr_res[0]);
302 /* Private per-CPU timer interface */
303 sc->prv_bst = rman_get_bustag(sc->tmr_res[2]);
304 sc->prv_bsh = rman_get_bushandle(sc->tmr_res[2]);
308 /* Disable both timers to start off */
309 tmr_prv_write_4(PRV_TIMER_CTRL, 0x00000000);
310 tmr_gbl_write_4(GBL_TIMER_CTRL, 0x00000000);
312 /* Setup and enable the global timer to use as the timecounter */
313 tmr_gbl_write_4(GBL_TIMER_CTRL, (0x00 << GBL_TIMER_CTR_PRESCALER_SHIFT) |
314 GBL_TIMER_CTRL_TIMER_ENABLE);
316 arm_tmr_timecount.tc_frequency = sc->clkfreq;
317 tc_init(&arm_tmr_timecount);
319 /* Setup and enable the timer */
320 if (bus_setup_intr(dev, sc->tmr_res[3], INTR_TYPE_CLK, arm_tmr_intr,
321 NULL, sc, &ihl) != 0) {
322 bus_release_resources(dev, arm_tmr_spec, sc->tmr_res);
323 device_printf(dev, "Unable to setup the clock irq handler.\n");
327 sc->et.et_name = "ARM MPCore Eventtimer";
328 sc->et.et_flags = ET_FLAGS_PERIODIC | ET_FLAGS_ONESHOT | ET_FLAGS_PERCPU;
329 sc->et.et_quality = 1000;
331 sc->et.et_frequency = sc->clkfreq;
332 sc->et.et_min_period = (0x00000002LLU << 32) / sc->et.et_frequency;
333 sc->et.et_max_period = (0xfffffffeLLU << 32) / sc->et.et_frequency;
334 sc->et.et_start = arm_tmr_start;
335 sc->et.et_stop = arm_tmr_stop;
337 et_register(&sc->et);
342 static device_method_t arm_tmr_methods[] = {
343 DEVMETHOD(device_probe, arm_tmr_probe),
344 DEVMETHOD(device_attach, arm_tmr_attach),
348 static driver_t arm_tmr_driver = {
351 sizeof(struct arm_tmr_softc),
354 static devclass_t arm_tmr_devclass;
356 DRIVER_MODULE(mp_tmr, simplebus, arm_tmr_driver, arm_tmr_devclass, 0, 0);
359 * cpu_initclocks - called by system to initialise the cpu clocks
361 * This is a boilerplat function, most of the setup has already been done
362 * when the driver was attached. Therefore this function must only be called
363 * after the driver is attached.
371 if (PCPU_GET(cpuid) == 0)
372 cpu_initclocks_bsp();
378 * DELAY - Delay for at least usec microseconds.
379 * @usec: number of microseconds to delay by
381 * This function is called all over the kernel and is suppose to provide a
382 * consistent delay. This function may also be called before the console
383 * is setup so no printf's can be called here.
391 int32_t counts_per_usec;
393 uint32_t first, last;
395 /* Check the timers are setup, if not just use a for loop for the meantime */
396 if (arm_tmr_sc == NULL) {
397 for (; usec > 0; usec--)
398 for (counts = 200; counts > 0; counts--)
399 cpufunc_nullop(); /* Prevent gcc from optimizing
405 /* Get the number of times to count */
406 counts_per_usec = ((arm_tmr_timecount.tc_frequency / 1000000) + 1);
409 * Clamp the timeout at a maximum value (about 32 seconds with
410 * a 66MHz clock). *Nobody* should be delay()ing for anywhere
411 * near that length of time and if they are, they should be hung
414 if (usec >= (0x80000000U / counts_per_usec))
415 counts = (0x80000000U / counts_per_usec) - 1;
417 counts = usec * counts_per_usec;
419 first = tmr_gbl_read_4(GBL_TIMER_COUNT_LOW);
422 last = tmr_gbl_read_4(GBL_TIMER_COUNT_LOW);
423 counts -= (int32_t)(last - first);