diff options
Diffstat (limited to 'arch/arm/mach-zynq/timer.c')
| -rw-r--r-- | arch/arm/mach-zynq/timer.c | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/arch/arm/mach-zynq/timer.c b/arch/arm/mach-zynq/timer.c new file mode 100644 index 0000000..5ed9642 --- /dev/null +++ b/arch/arm/mach-zynq/timer.c @@ -0,0 +1,168 @@ +/* + * Copyright (C) 2012 Michal Simek <monstr@monstr.eu> + * Copyright (C) 2011-2012 Xilinx, Inc. All rights reserved. + * + * (C) Copyright 2008 + * Guennadi Liakhovetki, DENX Software Engineering, <lg@denx.de> + * + * (C) Copyright 2004 + * Philippe Robin, ARM Ltd. <philippe.robin@arm.com> + * + * (C) Copyright 2002-2004 + * Gary Jennejohn, DENX Software Engineering, <gj@denx.de> + * + * (C) Copyright 2003 + * Texas Instruments <www.ti.com> + * + * (C) Copyright 2002 + * Sysgo Real-Time Solutions, GmbH <www.elinos.com> + * Marius Groeger <mgroeger@sysgo.de> + * + * (C) Copyright 2002 + * Sysgo Real-Time Solutions, GmbH <www.elinos.com> + * Alex Zuepke <azu@sysgo.de> + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#include <common.h> +#include <div64.h> +#include <asm/io.h> +#include <asm/arch/hardware.h> +#include <asm/arch/clk.h> + +DECLARE_GLOBAL_DATA_PTR; + +struct scu_timer { + u32 load; /* Timer Load Register */ + u32 counter; /* Timer Counter Register */ + u32 control; /* Timer Control Register */ +}; + +static struct scu_timer *timer_base = + (struct scu_timer *)ZYNQ_SCUTIMER_BASEADDR; + +#define SCUTIMER_CONTROL_PRESCALER_MASK 0x0000FF00 /* Prescaler */ +#define SCUTIMER_CONTROL_PRESCALER_SHIFT 8 +#define SCUTIMER_CONTROL_AUTO_RELOAD_MASK 0x00000002 /* Auto-reload */ +#define SCUTIMER_CONTROL_ENABLE_MASK 0x00000001 /* Timer enable */ + +#define TIMER_LOAD_VAL 0xFFFFFFFF +#define TIMER_PRESCALE 255 + +int timer_init(void) +{ + const u32 emask = SCUTIMER_CONTROL_AUTO_RELOAD_MASK | + (TIMER_PRESCALE << SCUTIMER_CONTROL_PRESCALER_SHIFT) | + SCUTIMER_CONTROL_ENABLE_MASK; + + gd->arch.timer_rate_hz = (gd->cpu_clk / 2) / (TIMER_PRESCALE + 1); + + /* Load the timer counter register */ + writel(0xFFFFFFFF, &timer_base->load); + + /* + * Start the A9Timer device + * Enable Auto reload mode, Clear prescaler control bits + * Set prescaler value, Enable the decrementer + */ + clrsetbits_le32(&timer_base->control, SCUTIMER_CONTROL_PRESCALER_MASK, + emask); + + /* Reset time */ + gd->arch.lastinc = readl(&timer_base->counter) / + (gd->arch.timer_rate_hz / CONFIG_SYS_HZ); + gd->arch.tbl = 0; + + return 0; +} + +/* + * This function is derived from PowerPC code (read timebase as long long). + * On ARM it just returns the timer value. + */ +ulong get_timer_masked(void) +{ + ulong now; + + now = readl(&timer_base->counter) / + (gd->arch.timer_rate_hz / CONFIG_SYS_HZ); + + if (gd->arch.lastinc >= now) { + /* Normal mode */ + gd->arch.tbl += gd->arch.lastinc - now; + } else { + /* We have an overflow ... */ + gd->arch.tbl += gd->arch.lastinc + (TIMER_LOAD_VAL / + (gd->arch.timer_rate_hz / CONFIG_SYS_HZ)) - + now + 1; + } + gd->arch.lastinc = now; + + return gd->arch.tbl; +} + +void __udelay(unsigned long usec) +{ + u32 countticks; + u32 timeend; + u32 timediff; + u32 timenow; + + if (usec == 0) + return; + + countticks = lldiv(((unsigned long long)gd->arch.timer_rate_hz * usec), + 1000000); + + /* decrementing timer */ + timeend = readl(&timer_base->counter) - countticks; + +#if TIMER_LOAD_VAL != 0xFFFFFFFF + /* do not manage multiple overflow */ + if (countticks >= TIMER_LOAD_VAL) + countticks = TIMER_LOAD_VAL - 1; +#endif + + do { + timenow = readl(&timer_base->counter); + + if (timenow >= timeend) { + /* normal case */ + timediff = timenow - timeend; + } else { + if ((TIMER_LOAD_VAL - timeend + timenow) <= + countticks) { + /* overflow */ + timediff = TIMER_LOAD_VAL - timeend + timenow; + } else { + /* missed the exact match */ + break; + } + } + } while (timediff > 0); +} + +/* Timer without interrupts */ +ulong get_timer(ulong base) +{ + return get_timer_masked() - base; +} + +/* + * This function is derived from PowerPC code (read timebase as long long). + * On ARM it just returns the timer value. + */ +unsigned long long get_ticks(void) +{ + return get_timer(0); +} + +/* + * This function is derived from PowerPC code (timebase clock frequency). + * On ARM it returns the number of timer ticks per second. + */ +ulong get_tbclk(void) +{ + return CONFIG_SYS_HZ; +} |