1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Copyright (C) 2019 Stephan Gerhold <stephan@gerhold.net>
5 * Based on arch/arm/cpu/armv7/u8500/timer.c:
6 * Copyright (C) 2010 Linaro Limited
7 * John Rigby <john.rigby@linaro.org>
9 * Based on Linux kernel source and internal ST-Ericsson U-Boot source:
10 * Copyright (C) 2009 Alessandro Rubini
11 * Copyright (C) 2010 ST-Ericsson
12 * Copyright (C) 2010 Linus Walleij for ST-Ericsson
20 #define MTU_NUM_TIMERS 4
23 struct nomadik_mtu_timer_regs {
24 u32 lr; /* Load register */
25 u32 cv; /* Current value */
26 u32 cr; /* Control register */
27 u32 bglr; /* Background load register */
30 /* The MTU that contains the timers */
31 struct nomadik_mtu_regs {
32 u32 imsc; /* Interrupt mask set/clear */
33 u32 ris; /* Raw interrupt status */
34 u32 mis; /* Masked interrupt status */
35 u32 icr; /* Interrupt clear register */
37 struct nomadik_mtu_timer_regs timers[MTU_NUM_TIMERS];
40 /* Bits for the control register */
41 #define MTU_CR_ONESHOT BIT(0) /* if 0 = wraps reloading from BGLR */
42 #define MTU_CR_32BITS BIT(1) /* if 0 = 16-bit counter */
44 #define MTU_CR_PRESCALE_SHIFT 2
45 #define MTU_CR_PRESCALE_1 (0 << MTU_CR_PRESCALE_SHIFT)
46 #define MTU_CR_PRESCALE_16 (1 << MTU_CR_PRESCALE_SHIFT)
47 #define MTU_CR_PRESCALE_256 (2 << MTU_CR_PRESCALE_SHIFT)
49 #define MTU_CR_PERIODIC BIT(6) /* if 0 = free-running */
50 #define MTU_CR_ENABLE BIT(7)
52 struct nomadik_mtu_priv {
53 struct nomadik_mtu_timer_regs *timer;
56 static int nomadik_mtu_get_count(struct udevice *dev, u64 *count)
58 struct nomadik_mtu_priv *priv = dev_get_priv(dev);
60 /* Decrementing counter: invert the value */
61 *count = timer_conv_64(~readl(&priv->timer->cv));
66 static int nomadik_mtu_probe(struct udevice *dev)
68 struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
69 struct nomadik_mtu_priv *priv = dev_get_priv(dev);
70 struct nomadik_mtu_regs *mtu;
74 addr = dev_read_addr(dev);
75 if (addr == FDT_ADDR_T_NONE)
78 mtu = (struct nomadik_mtu_regs *)addr;
79 priv->timer = mtu->timers; /* Use first timer */
81 if (!uc_priv->clock_rate)
84 /* Use divide-by-16 counter if tick rate is more than 32 MHz */
85 if (uc_priv->clock_rate > 32000000) {
86 uc_priv->clock_rate /= 16;
87 prescale = MTU_CR_PRESCALE_16;
89 prescale = MTU_CR_PRESCALE_1;
92 /* Configure a free-running, auto-wrap counter with selected prescale */
93 writel(MTU_CR_ENABLE | prescale | MTU_CR_32BITS, &priv->timer->cr);
98 static const struct timer_ops nomadik_mtu_ops = {
99 .get_count = nomadik_mtu_get_count,
102 static const struct udevice_id nomadik_mtu_ids[] = {
103 { .compatible = "st,nomadik-mtu" },
107 U_BOOT_DRIVER(nomadik_mtu) = {
108 .name = "nomadik_mtu",
110 .of_match = nomadik_mtu_ids,
111 .priv_auto_alloc_size = sizeof(struct nomadik_mtu_priv),
112 .probe = nomadik_mtu_probe,
113 .ops = &nomadik_mtu_ops,