]>
Commit | Line | Data |
---|---|---|
c066a32a | 1 | #include <linux/types.h> |
334955ef | 2 | #include <linux/i8253.h> |
c066a32a | 3 | #include <linux/interrupt.h> |
ca4d3e67 | 4 | #include <linux/irq.h> |
631330f5 | 5 | #include <linux/smp.h> |
c066a32a | 6 | #include <linux/time.h> |
c9294022 | 7 | #include <linux/clockchips.h> |
c066a32a TB |
8 | |
9 | #include <asm/sni.h> | |
10 | #include <asm/time.h> | |
11 | ||
70342287 RB |
12 | #define SNI_CLOCK_TICK_RATE 3686400 |
13 | #define SNI_COUNTER2_DIV 64 | |
14 | #define SNI_COUNTER0_DIV ((SNI_CLOCK_TICK_RATE / SNI_COUNTER2_DIV) / HZ) | |
c066a32a | 15 | |
397d08b0 | 16 | static int a20r_set_periodic(struct clock_event_device *evt) |
c066a32a | 17 | { |
397d08b0 VK |
18 | *(volatile u8 *)(A20R_PT_CLOCK_BASE + 12) = 0x34; |
19 | wmb(); | |
20 | *(volatile u8 *)(A20R_PT_CLOCK_BASE + 0) = SNI_COUNTER0_DIV; | |
21 | wmb(); | |
22 | *(volatile u8 *)(A20R_PT_CLOCK_BASE + 0) = SNI_COUNTER0_DIV >> 8; | |
23 | wmb(); | |
84953b39 | 24 | |
397d08b0 VK |
25 | *(volatile u8 *)(A20R_PT_CLOCK_BASE + 12) = 0xb4; |
26 | wmb(); | |
27 | *(volatile u8 *)(A20R_PT_CLOCK_BASE + 8) = SNI_COUNTER2_DIV; | |
28 | wmb(); | |
29 | *(volatile u8 *)(A20R_PT_CLOCK_BASE + 8) = SNI_COUNTER2_DIV >> 8; | |
30 | wmb(); | |
31 | return 0; | |
c066a32a TB |
32 | } |
33 | ||
84953b39 | 34 | static struct clock_event_device a20r_clockevent_device = { |
397d08b0 VK |
35 | .name = "a20r-timer", |
36 | .features = CLOCK_EVT_FEAT_PERIODIC, | |
84953b39 RB |
37 | |
38 | /* .mult, .shift, .max_delta_ns and .min_delta_ns left uninitialized */ | |
39 | ||
397d08b0 VK |
40 | .rating = 300, |
41 | .irq = SNI_A20R_IRQ_TIMER, | |
42 | .set_state_periodic = a20r_set_periodic, | |
84953b39 RB |
43 | }; |
44 | ||
45 | static irqreturn_t a20r_interrupt(int irq, void *dev_id) | |
46 | { | |
47 | struct clock_event_device *cd = dev_id; | |
48 | ||
49 | *(volatile u8 *)A20R_PT_TIM0_ACK = 0; | |
50 | wmb(); | |
51 | ||
52 | cd->event_handler(cd); | |
53 | ||
54 | return IRQ_HANDLED; | |
55 | } | |
56 | ||
57 | static struct irqaction a20r_irqaction = { | |
58 | .handler = a20r_interrupt, | |
8b5690f8 | 59 | .flags = IRQF_PERCPU | IRQF_TIMER, |
84953b39 RB |
60 | .name = "a20r-timer", |
61 | }; | |
62 | ||
c066a32a TB |
63 | /* |
64 | * a20r platform uses 2 counters to divide the input frequency. | |
65 | * Counter 2 output is connected to Counter 0 & 1 input. | |
66 | */ | |
84953b39 | 67 | static void __init sni_a20r_timer_setup(void) |
c066a32a | 68 | { |
84953b39 RB |
69 | struct clock_event_device *cd = &a20r_clockevent_device; |
70 | struct irqaction *action = &a20r_irqaction; | |
71 | unsigned int cpu = smp_processor_id(); | |
c066a32a | 72 | |
70342287 | 73 | cd->cpumask = cpumask_of(cpu); |
c9294022 | 74 | clockevents_register_device(cd); |
84953b39 RB |
75 | action->dev_id = cd; |
76 | setup_irq(SNI_A20R_IRQ_TIMER, &a20r_irqaction); | |
c066a32a TB |
77 | } |
78 | ||
70342287 | 79 | #define SNI_8254_TICK_RATE 1193182UL |
c066a32a | 80 | |
70342287 | 81 | #define SNI_8254_TCSAMP_COUNTER ((SNI_8254_TICK_RATE / HZ) + 255) |
c066a32a TB |
82 | |
83 | static __init unsigned long dosample(void) | |
84 | { | |
85 | u32 ct0, ct1; | |
11b9d0ec | 86 | volatile u8 msb; |
c066a32a TB |
87 | |
88 | /* Start the counter. */ | |
49a89efb | 89 | outb_p(0x34, 0x43); |
c066a32a | 90 | outb_p(SNI_8254_TCSAMP_COUNTER & 0xff, 0x40); |
49a89efb | 91 | outb(SNI_8254_TCSAMP_COUNTER >> 8, 0x40); |
c066a32a TB |
92 | |
93 | /* Get initial counter invariant */ | |
94 | ct0 = read_c0_count(); | |
95 | ||
96 | /* Latch and spin until top byte of counter0 is zero */ | |
97 | do { | |
49a89efb | 98 | outb(0x00, 0x43); |
11b9d0ec | 99 | (void) inb(0x40); |
49a89efb | 100 | msb = inb(0x40); |
c066a32a TB |
101 | ct1 = read_c0_count(); |
102 | } while (msb); | |
103 | ||
104 | /* Stop the counter. */ | |
49a89efb | 105 | outb(0x38, 0x43); |
c066a32a TB |
106 | /* |
107 | * Return the difference, this is how far the r4k counter increments | |
108 | * for every 1/HZ seconds. We round off the nearest 1 MHz of master | |
109 | * clock (= 1000000 / HZ / 2). | |
110 | */ | |
111 | /*return (ct1 - ct0 + (500000/HZ/2)) / (500000/HZ) * (500000/HZ);*/ | |
112 | return (ct1 - ct0) / (500000/HZ) * (500000/HZ); | |
113 | } | |
114 | ||
115 | /* | |
116 | * Here we need to calibrate the cycle counter to at least be close. | |
117 | */ | |
4b550488 | 118 | void __init plat_time_init(void) |
c066a32a TB |
119 | { |
120 | unsigned long r4k_ticks[3]; | |
121 | unsigned long r4k_tick; | |
122 | ||
123 | /* | |
124 | * Figure out the r4k offset, the algorithm is very simple and works in | |
125 | * _all_ cases as long as the 8254 counter register itself works ok (as | |
126 | * an interrupt driving timer it does not because of bug, this is why | |
127 | * we are using the onchip r4k counter/compare register to serve this | |
128 | * purpose, but for r4k_offset calculation it will work ok for us). | |
129 | * There are other very complicated ways of performing this calculation | |
130 | * but this one works just fine so I am not going to futz around. ;-) | |
131 | */ | |
132 | printk(KERN_INFO "Calibrating system timer... "); | |
133 | dosample(); /* Prime cache. */ | |
134 | dosample(); /* Prime cache. */ | |
135 | /* Zero is NOT an option. */ | |
136 | do { | |
137 | r4k_ticks[0] = dosample(); | |
138 | } while (!r4k_ticks[0]); | |
139 | do { | |
140 | r4k_ticks[1] = dosample(); | |
141 | } while (!r4k_ticks[1]); | |
142 | ||
143 | if (r4k_ticks[0] != r4k_ticks[1]) { | |
144 | printk("warning: timer counts differ, retrying... "); | |
145 | r4k_ticks[2] = dosample(); | |
146 | if (r4k_ticks[2] == r4k_ticks[0] | |
147 | || r4k_ticks[2] == r4k_ticks[1]) | |
148 | r4k_tick = r4k_ticks[2]; | |
149 | else { | |
150 | printk("disagreement, using average... "); | |
151 | r4k_tick = (r4k_ticks[0] + r4k_ticks[1] | |
152 | + r4k_ticks[2]) / 3; | |
153 | } | |
154 | } else | |
155 | r4k_tick = r4k_ticks[0]; | |
156 | ||
157 | printk("%d [%d.%04d MHz CPU]\n", (int) r4k_tick, | |
158 | (int) (r4k_tick / (500000 / HZ)), | |
159 | (int) (r4k_tick % (500000 / HZ))); | |
160 | ||
161 | mips_hpt_frequency = r4k_tick * HZ; | |
d865bea4 | 162 | |
c066a32a TB |
163 | switch (sni_brd_type) { |
164 | case SNI_BRD_10: | |
165 | case SNI_BRD_10NEW: | |
166 | case SNI_BRD_TOWER_OASIC: | |
167 | case SNI_BRD_MINITOWER: | |
84953b39 RB |
168 | sni_a20r_timer_setup(); |
169 | break; | |
c066a32a | 170 | } |
231a35d3 | 171 | setup_pit_timer(); |
c066a32a | 172 | } |
4b550488 | 173 | |
d4f587c6 | 174 | void read_persistent_clock(struct timespec *ts) |
4b550488 | 175 | { |
d4f587c6 MS |
176 | ts->tv_sec = -1; |
177 | ts->tv_nsec = 0; | |
4b550488 | 178 | } |