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- // SPDX-License-Identifier: GPL-2.0-or-later
- /*
- * Copyright (C) 2019 Stephan Gerhold <stephan@gerhold.net>
- *
- * Based on arch/arm/cpu/armv7/u8500/timer.c:
- * Copyright (C) 2010 Linaro Limited
- * John Rigby <john.rigby@linaro.org>
- *
- * Based on Linux kernel source and internal ST-Ericsson U-Boot source:
- * Copyright (C) 2009 Alessandro Rubini
- * Copyright (C) 2010 ST-Ericsson
- * Copyright (C) 2010 Linus Walleij for ST-Ericsson
- */
- #include <common.h>
- #include <dm.h>
- #include <timer.h>
- #include <asm/io.h>
- #include <linux/bitops.h>
- #define MTU_NUM_TIMERS 4
- /* The timers */
- struct nomadik_mtu_timer_regs {
- u32 lr; /* Load register */
- u32 cv; /* Current value */
- u32 cr; /* Control register */
- u32 bglr; /* Background load register */
- };
- /* The MTU that contains the timers */
- struct nomadik_mtu_regs {
- u32 imsc; /* Interrupt mask set/clear */
- u32 ris; /* Raw interrupt status */
- u32 mis; /* Masked interrupt status */
- u32 icr; /* Interrupt clear register */
- struct nomadik_mtu_timer_regs timers[MTU_NUM_TIMERS];
- };
- /* Bits for the control register */
- #define MTU_CR_ONESHOT BIT(0) /* if 0 = wraps reloading from BGLR */
- #define MTU_CR_32BITS BIT(1) /* if 0 = 16-bit counter */
- #define MTU_CR_PRESCALE_SHIFT 2
- #define MTU_CR_PRESCALE_1 (0 << MTU_CR_PRESCALE_SHIFT)
- #define MTU_CR_PRESCALE_16 (1 << MTU_CR_PRESCALE_SHIFT)
- #define MTU_CR_PRESCALE_256 (2 << MTU_CR_PRESCALE_SHIFT)
- #define MTU_CR_PERIODIC BIT(6) /* if 0 = free-running */
- #define MTU_CR_ENABLE BIT(7)
- struct nomadik_mtu_priv {
- struct nomadik_mtu_timer_regs *timer;
- };
- static u64 nomadik_mtu_get_count(struct udevice *dev)
- {
- struct nomadik_mtu_priv *priv = dev_get_priv(dev);
- /* Decrementing counter: invert the value */
- return timer_conv_64(~readl(&priv->timer->cv));
- }
- static int nomadik_mtu_probe(struct udevice *dev)
- {
- struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
- struct nomadik_mtu_priv *priv = dev_get_priv(dev);
- struct nomadik_mtu_regs *mtu;
- u32 prescale;
- mtu = dev_read_addr_ptr(dev);
- if (!mtu)
- return -EINVAL;
- priv->timer = mtu->timers; /* Use first timer */
- if (!uc_priv->clock_rate)
- return -EINVAL;
- /* Use divide-by-16 counter if tick rate is more than 32 MHz */
- if (uc_priv->clock_rate > 32000000) {
- uc_priv->clock_rate /= 16;
- prescale = MTU_CR_PRESCALE_16;
- } else {
- prescale = MTU_CR_PRESCALE_1;
- }
- /* Configure a free-running, auto-wrap counter with selected prescale */
- writel(MTU_CR_ENABLE | prescale | MTU_CR_32BITS, &priv->timer->cr);
- return 0;
- }
- static const struct timer_ops nomadik_mtu_ops = {
- .get_count = nomadik_mtu_get_count,
- };
- static const struct udevice_id nomadik_mtu_ids[] = {
- { .compatible = "st,nomadik-mtu" },
- {}
- };
- U_BOOT_DRIVER(nomadik_mtu) = {
- .name = "nomadik_mtu",
- .id = UCLASS_TIMER,
- .of_match = nomadik_mtu_ids,
- .priv_auto = sizeof(struct nomadik_mtu_priv),
- .probe = nomadik_mtu_probe,
- .ops = &nomadik_mtu_ops,
- };
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