// SPDX-License-Identifier: GPL-2.0-or-later /* * Copyright (C) 2019 Stephan Gerhold * * Based on arch/arm/cpu/armv7/u8500/timer.c: * Copyright (C) 2010 Linaro Limited * John Rigby * * 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 #include #include #include #include #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; fdt_addr_t addr; u32 prescale; addr = dev_read_addr(dev); if (addr == FDT_ADDR_T_NONE) return -EINVAL; mtu = (struct nomadik_mtu_regs *)addr; 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_alloc_size = sizeof(struct nomadik_mtu_priv), .probe = nomadik_mtu_probe, .ops = &nomadik_mtu_ops, };