2 * Time related functions for Hexagon architecture
4 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 and
8 * only version 2 as published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
21 #include <linux/init.h>
22 #include <linux/clockchips.h>
23 #include <linux/clocksource.h>
24 #include <linux/interrupt.h>
25 #include <linux/err.h>
26 #include <linux/platform_device.h>
27 #include <linux/ioport.h>
29 #include <linux/of_address.h>
30 #include <linux/of_irq.h>
31 #include <linux/module.h>
33 #include <asm/timer-regs.h>
34 #include <asm/hexagon_vm.h>
37 * For the clocksource we need:
38 * pcycle frequency (600MHz)
39 * For the loops_per_jiffy we need:
40 * thread/cpu frequency (100MHz)
41 * And for the timer, we need:
45 cycles_t pcycle_freq_mhz
;
46 cycles_t thread_freq_mhz
;
47 cycles_t sleep_clk_freq
;
49 static struct resource rtos_timer_resources
[] = {
51 .start
= RTOS_TIMER_REGS_ADDR
,
52 .end
= RTOS_TIMER_REGS_ADDR
+PAGE_SIZE
-1,
53 .flags
= IORESOURCE_MEM
,
57 static struct platform_device rtos_timer_device
= {
60 .num_resources
= ARRAY_SIZE(rtos_timer_resources
),
61 .resource
= rtos_timer_resources
,
64 /* A lot of this stuff should move into a platform specific section. */
65 struct adsp_hw_timer_struct
{
66 u32 match
; /* Match value */
68 u32 enable
; /* [1] - CLR_ON_MATCH_EN, [0] - EN */
69 u32 clear
; /* one-shot register that clears the count */
72 /* Look for "TCX0" for related constants. */
73 static __iomem
struct adsp_hw_timer_struct
*rtos_timer
;
75 static cycle_t
timer_get_cycles(struct clocksource
*cs
)
77 return (cycle_t
) __vmgettime();
80 static struct clocksource hexagon_clocksource
= {
83 .read
= timer_get_cycles
,
84 .mask
= CLOCKSOURCE_MASK(64),
85 .flags
= CLOCK_SOURCE_IS_CONTINUOUS
,
88 static int set_next_event(unsigned long delta
, struct clock_event_device
*evt
)
90 /* Assuming the timer will be disabled when we enter here. */
92 iowrite32(1, &rtos_timer
->clear
);
93 iowrite32(0, &rtos_timer
->clear
);
95 iowrite32(delta
, &rtos_timer
->match
);
96 iowrite32(1 << TIMER_ENABLE
, &rtos_timer
->enable
);
101 * Sets the mode (periodic, shutdown, oneshot, etc) of a timer.
103 static void set_mode(enum clock_event_mode mode
,
104 struct clock_event_device
*evt
)
107 case CLOCK_EVT_MODE_SHUTDOWN
:
108 /* XXX implement me */
115 /* Broadcast mechanism */
116 static void broadcast(const struct cpumask
*mask
)
118 send_ipi(mask
, IPI_TIMER
);
122 static struct clock_event_device hexagon_clockevent_dev
= {
123 .name
= "clockevent",
124 .features
= CLOCK_EVT_FEAT_ONESHOT
,
126 .irq
= RTOS_TIMER_INT
,
127 .set_next_event
= set_next_event
,
128 .set_mode
= set_mode
,
130 .broadcast
= broadcast
,
135 static DEFINE_PER_CPU(struct clock_event_device
, clock_events
);
137 void setup_percpu_clockdev(void)
139 int cpu
= smp_processor_id();
140 struct clock_event_device
*ce_dev
= &hexagon_clockevent_dev
;
141 struct clock_event_device
*dummy_clock_dev
=
142 &per_cpu(clock_events
, cpu
);
144 memcpy(dummy_clock_dev
, ce_dev
, sizeof(*dummy_clock_dev
));
145 INIT_LIST_HEAD(&dummy_clock_dev
->list
);
147 dummy_clock_dev
->features
= CLOCK_EVT_FEAT_DUMMY
;
148 dummy_clock_dev
->cpumask
= cpumask_of(cpu
);
149 dummy_clock_dev
->mode
= CLOCK_EVT_MODE_UNUSED
;
151 clockevents_register_device(dummy_clock_dev
);
154 /* Called from smp.c for each CPU's timer ipi call */
157 int cpu
= smp_processor_id();
158 struct clock_event_device
*ce_dev
= &per_cpu(clock_events
, cpu
);
160 ce_dev
->event_handler(ce_dev
);
162 #endif /* CONFIG_SMP */
164 static irqreturn_t
timer_interrupt(int irq
, void *devid
)
166 struct clock_event_device
*ce_dev
= &hexagon_clockevent_dev
;
168 iowrite32(0, &rtos_timer
->enable
);
169 ce_dev
->event_handler(ce_dev
);
174 /* This should also be pulled from devtree */
175 static struct irqaction rtos_timer_intdesc
= {
176 .handler
= timer_interrupt
,
177 .flags
= IRQF_TIMER
| IRQF_TRIGGER_RISING
,
182 * time_init_deferred - called by start_kernel to set up timer/clock source
184 * Install the IRQ handler for the clock, setup timers.
185 * This is done late, as that way, we can use ioremap().
187 * This runs just before the delay loop is calibrated, and
188 * is used for delay calibration.
190 void __init
time_init_deferred(void)
192 struct resource
*resource
= NULL
;
193 struct clock_event_device
*ce_dev
= &hexagon_clockevent_dev
;
195 ce_dev
->cpumask
= cpu_all_mask
;
198 resource
= rtos_timer_device
.resource
;
200 /* ioremap here means this has to run later, after paging init */
201 rtos_timer
= ioremap(resource
->start
, resource_size(resource
));
204 release_mem_region(resource
->start
, resource_size(resource
));
206 clocksource_register_khz(&hexagon_clocksource
, pcycle_freq_mhz
* 1000);
208 /* Note: the sim generic RTOS clock is apparently really 18750Hz */
211 * Last arg is some guaranteed seconds for which the conversion will
212 * work without overflow.
214 clockevents_calc_mult_shift(ce_dev
, sleep_clk_freq
, 4);
216 ce_dev
->max_delta_ns
= clockevent_delta2ns(0x7fffffff, ce_dev
);
217 ce_dev
->min_delta_ns
= clockevent_delta2ns(0xf, ce_dev
);
220 setup_percpu_clockdev();
223 clockevents_register_device(ce_dev
);
224 setup_irq(ce_dev
->irq
, &rtos_timer_intdesc
);
227 void __init
time_init(void)
229 late_time_init
= time_init_deferred
;
232 void __delay(unsigned long cycles
)
234 unsigned long long start
= __vmgettime();
236 while ((__vmgettime() - start
) < cycles
)
239 EXPORT_SYMBOL(__delay
);
242 * This could become parametric or perhaps even computed at run-time,
243 * but for now we take the observed simulator jitter.
245 static long long fudgefactor
= 350; /* Maybe lower if kernel optimized. */
247 void __udelay(unsigned long usecs
)
249 unsigned long long start
= __vmgettime();
250 unsigned long long finish
= (pcycle_freq_mhz
* usecs
) - fudgefactor
;
252 while ((__vmgettime() - start
) < finish
)
253 cpu_relax(); /* not sure how this improves readability */
255 EXPORT_SYMBOL(__udelay
);