2 * linux/arch/cris/arch-v32/kernel/time.c
4 * Copyright (C) 2003-2010 Axis Communications AB
8 #include <linux/timex.h>
9 #include <linux/time.h>
10 #include <linux/clocksource.h>
11 #include <linux/interrupt.h>
12 #include <linux/swap.h>
13 #include <linux/sched.h>
14 #include <linux/init.h>
15 #include <linux/threads.h>
16 #include <linux/cpufreq.h>
18 #include <asm/types.h>
19 #include <asm/signal.h>
21 #include <asm/delay.h>
23 #include <asm/irq_regs.h>
25 #include <hwregs/reg_map.h>
26 #include <hwregs/reg_rdwr.h>
27 #include <hwregs/timer_defs.h>
28 #include <hwregs/intr_vect_defs.h>
29 #ifdef CONFIG_CRIS_MACH_ARTPEC3
30 #include <hwregs/clkgen_defs.h>
33 /* Watchdog defines */
34 #define ETRAX_WD_KEY_MASK 0x7F /* key is 7 bit */
35 #define ETRAX_WD_HZ 763 /* watchdog counts at 763 Hz */
36 /* Number of 763 counts before watchdog bites */
37 #define ETRAX_WD_CNT ((2*ETRAX_WD_HZ)/HZ + 1)
39 /* Register the continuos readonly timer available in FS and ARTPEC-3. */
40 static cycle_t read_cont_rotime(struct clocksource *cs)
42 return (u32)REG_RD(timer, regi_timer0, r_time);
45 static struct clocksource cont_rotime = {
46 .name = "crisv32_rotime",
48 .read = read_cont_rotime,
49 .mask = CLOCKSOURCE_MASK(32),
50 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
53 static int __init etrax_init_cont_rotime(void)
55 clocksource_register_khz(&cont_rotime, 100000);
58 arch_initcall(etrax_init_cont_rotime);
61 unsigned long timer_regs[NR_CPUS] =
69 extern int set_rtc_mmss(unsigned long nowtime);
71 #ifdef CONFIG_CPU_FREQ
73 cris_time_freq_notifier(struct notifier_block *nb, unsigned long val,
76 static struct notifier_block cris_time_freq_notifier_block = {
77 .notifier_call = cris_time_freq_notifier,
81 unsigned long get_ns_in_jiffie(void)
83 reg_timer_r_tmr0_data data;
86 data = REG_RD(timer, regi_timer0, r_tmr0_data);
87 ns = (TIMER0_DIV - data) * 10;
92 /* From timer MDS describing the hardware watchdog:
93 * 4.3.1 Watchdog Operation
94 * The watchdog timer is an 8-bit timer with a configurable start value.
95 * Once started the watchdog counts downwards with a frequency of 763 Hz
96 * (100/131072 MHz). When the watchdog counts down to 1, it generates an
97 * NMI (Non Maskable Interrupt), and when it counts down to 0, it resets the
100 /* This gives us 1.3 ms to do something useful when the NMI comes */
102 /* Right now, starting the watchdog is the same as resetting it */
103 #define start_watchdog reset_watchdog
105 #if defined(CONFIG_ETRAX_WATCHDOG)
106 static short int watchdog_key = 42; /* arbitrary 7 bit number */
109 /* Number of pages to consider "out of memory". It is normal that the memory
110 * is used though, so set this really low. */
111 #define WATCHDOG_MIN_FREE_PAGES 8
113 void reset_watchdog(void)
115 #if defined(CONFIG_ETRAX_WATCHDOG)
116 reg_timer_rw_wd_ctrl wd_ctrl = { 0 };
118 /* Only keep watchdog happy as long as we have memory left! */
119 if(nr_free_pages() > WATCHDOG_MIN_FREE_PAGES) {
120 /* Reset the watchdog with the inverse of the old key */
121 /* Invert key, which is 7 bits */
122 watchdog_key ^= ETRAX_WD_KEY_MASK;
123 wd_ctrl.cnt = ETRAX_WD_CNT;
124 wd_ctrl.cmd = regk_timer_start;
125 wd_ctrl.key = watchdog_key;
126 REG_WR(timer, regi_timer0, rw_wd_ctrl, wd_ctrl);
131 /* stop the watchdog - we still need the correct key */
133 void stop_watchdog(void)
135 #if defined(CONFIG_ETRAX_WATCHDOG)
136 reg_timer_rw_wd_ctrl wd_ctrl = { 0 };
137 watchdog_key ^= ETRAX_WD_KEY_MASK; /* invert key, which is 7 bits */
138 wd_ctrl.cnt = ETRAX_WD_CNT;
139 wd_ctrl.cmd = regk_timer_stop;
140 wd_ctrl.key = watchdog_key;
141 REG_WR(timer, regi_timer0, rw_wd_ctrl, wd_ctrl);
145 extern void show_registers(struct pt_regs *regs);
147 void handle_watchdog_bite(struct pt_regs *regs)
149 #if defined(CONFIG_ETRAX_WATCHDOG)
150 extern int cause_of_death;
152 oops_in_progress = 1;
153 printk(KERN_WARNING "Watchdog bite\n");
155 /* Check if forced restart or unexpected watchdog */
156 if (cause_of_death == 0xbedead) {
157 #ifdef CONFIG_CRIS_MACH_ARTPEC3
158 /* There is a bug in Artpec-3 (voodoo TR 78) that requires
159 * us to go to lower frequency for the reset to be reliable
161 reg_clkgen_rw_clk_ctrl ctrl =
162 REG_RD(clkgen, regi_clkgen, rw_clk_ctrl);
164 REG_WR(clkgen, regi_clkgen, rw_clk_ctrl, ctrl);
169 /* Unexpected watchdog, stop the watchdog and dump registers. */
171 printk(KERN_WARNING "Oops: bitten by watchdog\n");
172 show_registers(regs);
173 oops_in_progress = 0;
174 #ifndef CONFIG_ETRAX_WATCHDOG_NICE_DOGGY
177 while(1) /* nothing */;
182 * timer_interrupt() needs to keep up the real-time clock,
183 * as well as call the "xtime_update()" routine every clocktick.
185 extern void cris_do_profile(struct pt_regs *regs);
187 static inline irqreturn_t timer_interrupt(int irq, void *dev_id)
189 struct pt_regs *regs = get_irq_regs();
190 int cpu = smp_processor_id();
191 reg_timer_r_masked_intr masked_intr;
192 reg_timer_rw_ack_intr ack_intr = { 0 };
194 /* Check if the timer interrupt is for us (a tmr0 int) */
195 masked_intr = REG_RD(timer, timer_regs[cpu], r_masked_intr);
196 if (!masked_intr.tmr0)
199 /* Acknowledge the timer irq. */
201 REG_WR(timer, timer_regs[cpu], rw_ack_intr, ack_intr);
203 /* Reset watchdog otherwise it resets us! */
206 /* Update statistics. */
207 update_process_times(user_mode(regs));
209 cris_do_profile(regs); /* Save profiling information */
211 /* The master CPU is responsible for the time keeping. */
215 /* Call the real timer interrupt handler */
220 /* Timer is IRQF_SHARED so drivers can add stuff to the timer irq chain. */
221 static struct irqaction irq_timer = {
222 .handler = timer_interrupt,
223 .flags = IRQF_SHARED,
227 void __init cris_timer_init(void)
229 int cpu = smp_processor_id();
230 reg_timer_rw_tmr0_ctrl tmr0_ctrl = { 0 };
231 reg_timer_rw_tmr0_div tmr0_div = TIMER0_DIV;
232 reg_timer_rw_intr_mask timer_intr_mask;
234 /* Setup the etrax timers.
235 * Base frequency is 100MHz, divider 1000000 -> 100 HZ
236 * We use timer0, so timer1 is free.
237 * The trig timer is used by the fasttimer API if enabled.
240 tmr0_ctrl.op = regk_timer_ld;
241 tmr0_ctrl.freq = regk_timer_f100;
242 REG_WR(timer, timer_regs[cpu], rw_tmr0_div, tmr0_div);
243 REG_WR(timer, timer_regs[cpu], rw_tmr0_ctrl, tmr0_ctrl); /* Load */
244 tmr0_ctrl.op = regk_timer_run;
245 REG_WR(timer, timer_regs[cpu], rw_tmr0_ctrl, tmr0_ctrl); /* Start */
247 /* Enable the timer irq. */
248 timer_intr_mask = REG_RD(timer, timer_regs[cpu], rw_intr_mask);
249 timer_intr_mask.tmr0 = 1;
250 REG_WR(timer, timer_regs[cpu], rw_intr_mask, timer_intr_mask);
253 void __init time_init(void)
255 reg_intr_vect_rw_mask intr_mask;
257 /* Probe for the RTC and read it if it exists.
258 * Before the RTC can be probed the loops_per_usec variable needs
259 * to be initialized to make usleep work. A better value for
260 * loops_per_usec is calculated by the kernel later once the
265 /* Start CPU local timer. */
268 /* Enable the timer irq in global config. */
269 intr_mask = REG_RD_VECT(intr_vect, regi_irq, rw_mask, 1);
270 intr_mask.timer0 = 1;
271 REG_WR_VECT(intr_vect, regi_irq, rw_mask, 1, intr_mask);
273 /* Now actually register the timer irq handler that calls
274 * timer_interrupt(). */
275 setup_irq(TIMER0_INTR_VECT, &irq_timer);
277 /* Enable watchdog if we should use one. */
279 #if defined(CONFIG_ETRAX_WATCHDOG)
280 printk(KERN_INFO "Enabling watchdog...\n");
283 /* If we use the hardware watchdog, we want to trap it as an NMI
284 * and dump registers before it resets us. For this to happen, we
285 * must set the "m" NMI enable flag (which once set, is unset only
286 * when an NMI is taken). */
289 local_save_flags(flags);
290 flags |= (1<<30); /* NMI M flag is at bit 30 */
291 local_irq_restore(flags);
295 #ifdef CONFIG_CPU_FREQ
296 cpufreq_register_notifier(&cris_time_freq_notifier_block,
297 CPUFREQ_TRANSITION_NOTIFIER);
301 #ifdef CONFIG_CPU_FREQ
303 cris_time_freq_notifier(struct notifier_block *nb, unsigned long val,
306 struct cpufreq_freqs *freqs = data;
307 if (val == CPUFREQ_POSTCHANGE) {
308 reg_timer_r_tmr0_data data;
309 reg_timer_rw_tmr0_div div = (freqs->new * 500) / HZ;
311 data = REG_RD(timer, timer_regs[freqs->cpu],
314 REG_WR(timer, timer_regs[freqs->cpu], rw_tmr0_div, div);