]>
Commit | Line | Data |
---|---|---|
d5254f14 | 1 | /* |
095a460b | 2 | * (C) Copyright 2009 Alessandro Rubini |
d5254f14 | 3 | * |
1a459660 | 4 | * SPDX-License-Identifier: GPL-2.0+ |
d5254f14 AR |
5 | */ |
6 | ||
7 | #include <common.h> | |
8 | #include <asm/io.h> | |
095a460b | 9 | #include <asm/arch/mtu.h> |
d5254f14 | 10 | |
095a460b AR |
11 | /* |
12 | * The timer is a decrementer, we'll left it free running at 2.4MHz. | |
13 | * We have 2.4 ticks per microsecond and an overflow in almost 30min | |
14 | */ | |
15 | #define TIMER_CLOCK (24 * 100 * 1000) | |
16 | #define COUNT_TO_USEC(x) ((x) * 5 / 12) /* overflows at 6min */ | |
17 | #define USEC_TO_COUNT(x) ((x) * 12 / 5) /* overflows at 6min */ | |
18 | #define TICKS_PER_HZ (TIMER_CLOCK / CONFIG_SYS_HZ) | |
19 | #define TICKS_TO_HZ(x) ((x) / TICKS_PER_HZ) | |
d5254f14 | 20 | |
4b894a97 AR |
21 | /* macro to read the decrementing 32 bit timer as an increasing count */ |
22 | #define READ_TIMER() (0 - readl(CONFIG_SYS_TIMERBASE + MTU_VAL(0))) | |
d5254f14 | 23 | |
095a460b | 24 | /* Configure a free-running, auto-wrap counter with no prescaler */ |
d5254f14 AR |
25 | int timer_init(void) |
26 | { | |
4769be21 GR |
27 | ulong val; |
28 | ||
095a460b AR |
29 | writel(MTU_CRn_ENA | MTU_CRn_PRESCALE_1 | MTU_CRn_32BITS, |
30 | CONFIG_SYS_TIMERBASE + MTU_CR(0)); | |
d5254f14 | 31 | |
4769be21 | 32 | /* Reset the timer */ |
4b894a97 AR |
33 | writel(0, CONFIG_SYS_TIMERBASE + MTU_LR(0)); |
34 | /* | |
35 | * The load-register isn't really immediate: it changes on clock | |
36 | * edges, so we must wait for our newly-written value to appear. | |
37 | * Since we might miss reading 0, wait for any change in value. | |
38 | */ | |
39 | val = READ_TIMER(); | |
40 | while (READ_TIMER() == val) | |
41 | ; | |
4769be21 GR |
42 | |
43 | return 0; | |
d5254f14 AR |
44 | } |
45 | ||
095a460b | 46 | /* Return how many HZ passed since "base" */ |
d5254f14 AR |
47 | ulong get_timer(ulong base) |
48 | { | |
095a460b | 49 | return TICKS_TO_HZ(READ_TIMER()) - base; |
d5254f14 AR |
50 | } |
51 | ||
095a460b | 52 | /* Delay x useconds */ |
3eb90bad | 53 | void __udelay(unsigned long usec) |
d5254f14 | 54 | { |
095a460b | 55 | ulong ini, end; |
d5254f14 | 56 | |
095a460b AR |
57 | ini = READ_TIMER(); |
58 | end = ini + USEC_TO_COUNT(usec); | |
59 | while ((signed)(end - READ_TIMER()) > 0) | |
60 | ; | |
d5254f14 | 61 | } |
b39643b7 AG |
62 | |
63 | unsigned long long get_ticks(void) | |
64 | { | |
65 | return get_timer(0); | |
66 | } | |
67 | ||
68 | ulong get_tbclk(void) | |
69 | { | |
70 | return CONFIG_SYS_HZ; | |
71 | } |