xref: /openbmc/u-boot/arch/arm/mach-mvebu/timer.c (revision fea7f3aa)
1 /*
2  * Copyright (C) Marvell International Ltd. and its affiliates
3  * Written-by: Prafulla Wadaskar <prafulla@marvell.com>
4  *
5  * SPDX-License-Identifier:	GPL-2.0+
6  */
7 
8 #include <common.h>
9 #include <asm/io.h>
10 #include <asm/arch/soc.h>
11 
12 #define UBOOT_CNTR	0	/* counter to use for U-Boot timer */
13 
14 /*
15  * ARM Timers Registers Map
16  */
17 #define CNTMR_CTRL_REG			&tmr_regs->ctrl
18 #define CNTMR_RELOAD_REG(tmrnum)	&tmr_regs->tmr[tmrnum].reload
19 #define CNTMR_VAL_REG(tmrnum)		&tmr_regs->tmr[tmrnum].val
20 
21 /*
22  * ARM Timers Control Register
23  * CPU_TIMERS_CTRL_REG (CTCR)
24  */
25 #define CTCR_ARM_TIMER_EN_OFFS(cntr)	(cntr * 2)
26 #define CTCR_ARM_TIMER_EN(cntr)		(1 << CTCR_ARM_TIMER_EN_OFFS(cntr))
27 
28 #define CTCR_ARM_TIMER_AUTO_OFFS(cntr)	((cntr * 2) + 1)
29 #define CTCR_ARM_TIMER_AUTO_EN(cntr)	(1 << CTCR_ARM_TIMER_AUTO_OFFS(cntr))
30 
31 /* Only Armada XP have the 25MHz enable bit (Kirkwood doesn't) */
32 #if defined(CONFIG_ARMADA_XP)
33 #define CTCR_ARM_TIMER_25MHZ_OFFS(cntr)	(cntr + 11)
34 #define CTCR_ARM_TIMER_25MHZ(cntr)	(1 << CTCR_ARM_TIMER_25MHZ_OFFS(cntr))
35 #else
36 #define CTCR_ARM_TIMER_25MHZ(cntr)	0
37 #endif
38 
39 #define TIMER_LOAD_VAL 			0xffffffff
40 
41 #define timestamp			gd->arch.tbl
42 #define lastdec				gd->arch.lastinc
43 
44 static int init_done __attribute__((section(".data"))) = 0;
45 
46 /* Timer reload and current value registers */
47 struct kwtmr_val {
48 	u32 reload;	/* Timer reload reg */
49 	u32 val;	/* Timer value reg */
50 };
51 
52 /* Timer registers */
53 struct kwtmr_registers {
54 	u32 ctrl;	/* Timer control reg */
55 	u32 pad[3];
56 	struct kwtmr_val tmr[4];
57 	u32 wdt_reload;
58 	u32 wdt_val;
59 };
60 
61 DECLARE_GLOBAL_DATA_PTR;
62 
63 static struct kwtmr_registers *tmr_regs =
64 	(struct kwtmr_registers *)MVEBU_TIMER_BASE;
65 
66 static inline ulong read_timer(void)
67 {
68 	return readl(CNTMR_VAL_REG(UBOOT_CNTR))	/ (CONFIG_SYS_TCLK / 1000);
69 }
70 
71 ulong get_timer_masked(void)
72 {
73 	ulong now = read_timer();
74 
75 	if (lastdec >= now) {
76 		/* normal mode */
77 		timestamp += lastdec - now;
78 	} else {
79 		/* we have an overflow ... */
80 		timestamp += lastdec +
81 			(TIMER_LOAD_VAL / (CONFIG_SYS_TCLK / 1000)) - now;
82 	}
83 	lastdec = now;
84 
85 	return timestamp;
86 }
87 
88 ulong get_timer(ulong base)
89 {
90 	return get_timer_masked() - base;
91 }
92 
93 void __udelay(unsigned long usec)
94 {
95 	uint current;
96 	ulong delayticks;
97 
98 	current = readl(CNTMR_VAL_REG(UBOOT_CNTR));
99 	delayticks = (usec * (CONFIG_SYS_TCLK / 1000000));
100 
101 	if (current < delayticks) {
102 		delayticks -= current;
103 		while (readl(CNTMR_VAL_REG(UBOOT_CNTR)) < current) ;
104 		while ((TIMER_LOAD_VAL - delayticks) <
105 			readl(CNTMR_VAL_REG(UBOOT_CNTR))) ;
106 	} else {
107 		while (readl(CNTMR_VAL_REG(UBOOT_CNTR)) >
108 			(current - delayticks)) ;
109 	}
110 }
111 
112 /*
113  * init the counter
114  */
115 int timer_init(void)
116 {
117 	/* Only init the timer once */
118 	if (init_done)
119 		return 0;
120 	init_done = 1;
121 
122 	/* load value into timer */
123 	writel(TIMER_LOAD_VAL, CNTMR_RELOAD_REG(UBOOT_CNTR));
124 	writel(TIMER_LOAD_VAL, CNTMR_VAL_REG(UBOOT_CNTR));
125 
126 	/* enable timer in auto reload mode */
127 	clrsetbits_le32(CNTMR_CTRL_REG, CTCR_ARM_TIMER_25MHZ(UBOOT_CNTR),
128 			CTCR_ARM_TIMER_EN(UBOOT_CNTR) |
129 			CTCR_ARM_TIMER_AUTO_EN(UBOOT_CNTR));
130 
131 	/* init the timestamp and lastdec value */
132 	lastdec = read_timer();
133 	timestamp = 0;
134 
135 	return 0;
136 }
137 
138 /*
139  * This function is derived from PowerPC code (read timebase as long long).
140  * On ARM it just returns the timer value.
141  */
142 unsigned long long get_ticks(void)
143 {
144 	return get_timer(0);
145 }
146 
147 /*
148  * This function is derived from PowerPC code (timebase clock frequency).
149  * On ARM it returns the number of timer ticks per second.
150  */
151 ulong get_tbclk (void)
152 {
153 	return (ulong)CONFIG_SYS_HZ;
154 }
155