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17deb9c2db
Update to tip/timers/core and resolve minor conflict. Conflicts: drivers/clocksource/samsung_pwm_timer.c Signed-off-by: John Stultz <john.stultz@linaro.org>
287 lines
7.6 KiB
C
287 lines
7.6 KiB
C
/*
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* Copyright (C) 2008 STMicroelectronics
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* Copyright (C) 2010 Alessandro Rubini
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* Copyright (C) 2010 Linus Walleij for ST-Ericsson
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2, as
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* published by the Free Software Foundation.
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*/
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/irq.h>
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#include <linux/io.h>
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#include <linux/clockchips.h>
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#include <linux/clocksource.h>
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#include <linux/of_address.h>
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#include <linux/of_irq.h>
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#include <linux/of_platform.h>
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#include <linux/clk.h>
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#include <linux/jiffies.h>
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#include <linux/delay.h>
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#include <linux/err.h>
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#include <linux/platform_data/clocksource-nomadik-mtu.h>
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#include <linux/sched_clock.h>
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#include <asm/mach/time.h>
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/*
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* The MTU device hosts four different counters, with 4 set of
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* registers. These are register names.
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*/
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#define MTU_IMSC 0x00 /* Interrupt mask set/clear */
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#define MTU_RIS 0x04 /* Raw interrupt status */
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#define MTU_MIS 0x08 /* Masked interrupt status */
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#define MTU_ICR 0x0C /* Interrupt clear register */
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/* per-timer registers take 0..3 as argument */
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#define MTU_LR(x) (0x10 + 0x10 * (x) + 0x00) /* Load value */
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#define MTU_VAL(x) (0x10 + 0x10 * (x) + 0x04) /* Current value */
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#define MTU_CR(x) (0x10 + 0x10 * (x) + 0x08) /* Control reg */
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#define MTU_BGLR(x) (0x10 + 0x10 * (x) + 0x0c) /* At next overflow */
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/* bits for the control register */
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#define MTU_CRn_ENA 0x80
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#define MTU_CRn_PERIODIC 0x40 /* if 0 = free-running */
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#define MTU_CRn_PRESCALE_MASK 0x0c
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#define MTU_CRn_PRESCALE_1 0x00
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#define MTU_CRn_PRESCALE_16 0x04
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#define MTU_CRn_PRESCALE_256 0x08
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#define MTU_CRn_32BITS 0x02
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#define MTU_CRn_ONESHOT 0x01 /* if 0 = wraps reloading from BGLR*/
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/* Other registers are usual amba/primecell registers, currently not used */
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#define MTU_ITCR 0xff0
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#define MTU_ITOP 0xff4
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#define MTU_PERIPH_ID0 0xfe0
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#define MTU_PERIPH_ID1 0xfe4
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#define MTU_PERIPH_ID2 0xfe8
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#define MTU_PERIPH_ID3 0xfeC
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#define MTU_PCELL0 0xff0
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#define MTU_PCELL1 0xff4
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#define MTU_PCELL2 0xff8
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#define MTU_PCELL3 0xffC
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static void __iomem *mtu_base;
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static bool clkevt_periodic;
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static u32 clk_prescale;
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static u32 nmdk_cycle; /* write-once */
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static struct delay_timer mtu_delay_timer;
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#ifdef CONFIG_CLKSRC_NOMADIK_MTU_SCHED_CLOCK
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/*
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* Override the global weak sched_clock symbol with this
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* local implementation which uses the clocksource to get some
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* better resolution when scheduling the kernel.
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*/
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static u64 notrace nomadik_read_sched_clock(void)
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{
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if (unlikely(!mtu_base))
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return 0;
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return -readl(mtu_base + MTU_VAL(0));
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}
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#endif
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static unsigned long nmdk_timer_read_current_timer(void)
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{
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return ~readl_relaxed(mtu_base + MTU_VAL(0));
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}
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/* Clockevent device: use one-shot mode */
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static int nmdk_clkevt_next(unsigned long evt, struct clock_event_device *ev)
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{
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writel(1 << 1, mtu_base + MTU_IMSC);
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writel(evt, mtu_base + MTU_LR(1));
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/* Load highest value, enable device, enable interrupts */
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writel(MTU_CRn_ONESHOT | clk_prescale |
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MTU_CRn_32BITS | MTU_CRn_ENA,
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mtu_base + MTU_CR(1));
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return 0;
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}
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void nmdk_clkevt_reset(void)
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{
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if (clkevt_periodic) {
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/* Timer: configure load and background-load, and fire it up */
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writel(nmdk_cycle, mtu_base + MTU_LR(1));
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writel(nmdk_cycle, mtu_base + MTU_BGLR(1));
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writel(MTU_CRn_PERIODIC | clk_prescale |
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MTU_CRn_32BITS | MTU_CRn_ENA,
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mtu_base + MTU_CR(1));
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writel(1 << 1, mtu_base + MTU_IMSC);
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} else {
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/* Generate an interrupt to start the clockevent again */
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(void) nmdk_clkevt_next(nmdk_cycle, NULL);
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}
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}
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static void nmdk_clkevt_mode(enum clock_event_mode mode,
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struct clock_event_device *dev)
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{
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switch (mode) {
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case CLOCK_EVT_MODE_PERIODIC:
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clkevt_periodic = true;
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nmdk_clkevt_reset();
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break;
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case CLOCK_EVT_MODE_ONESHOT:
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clkevt_periodic = false;
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break;
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case CLOCK_EVT_MODE_SHUTDOWN:
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case CLOCK_EVT_MODE_UNUSED:
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writel(0, mtu_base + MTU_IMSC);
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/* disable timer */
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writel(0, mtu_base + MTU_CR(1));
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/* load some high default value */
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writel(0xffffffff, mtu_base + MTU_LR(1));
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break;
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case CLOCK_EVT_MODE_RESUME:
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break;
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}
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}
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void nmdk_clksrc_reset(void)
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{
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/* Disable */
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writel(0, mtu_base + MTU_CR(0));
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/* ClockSource: configure load and background-load, and fire it up */
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writel(nmdk_cycle, mtu_base + MTU_LR(0));
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writel(nmdk_cycle, mtu_base + MTU_BGLR(0));
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writel(clk_prescale | MTU_CRn_32BITS | MTU_CRn_ENA,
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mtu_base + MTU_CR(0));
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}
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static void nmdk_clkevt_resume(struct clock_event_device *cedev)
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{
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nmdk_clkevt_reset();
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nmdk_clksrc_reset();
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}
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static struct clock_event_device nmdk_clkevt = {
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.name = "mtu_1",
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.features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC |
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CLOCK_EVT_FEAT_DYNIRQ,
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.rating = 200,
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.set_mode = nmdk_clkevt_mode,
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.set_next_event = nmdk_clkevt_next,
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.resume = nmdk_clkevt_resume,
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};
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/*
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* IRQ Handler for timer 1 of the MTU block.
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*/
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static irqreturn_t nmdk_timer_interrupt(int irq, void *dev_id)
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{
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struct clock_event_device *evdev = dev_id;
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writel(1 << 1, mtu_base + MTU_ICR); /* Interrupt clear reg */
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evdev->event_handler(evdev);
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return IRQ_HANDLED;
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}
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static struct irqaction nmdk_timer_irq = {
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.name = "Nomadik Timer Tick",
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.flags = IRQF_DISABLED | IRQF_TIMER,
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.handler = nmdk_timer_interrupt,
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.dev_id = &nmdk_clkevt,
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};
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static void __init __nmdk_timer_init(void __iomem *base, int irq,
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struct clk *pclk, struct clk *clk)
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{
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unsigned long rate;
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mtu_base = base;
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BUG_ON(clk_prepare_enable(pclk));
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BUG_ON(clk_prepare_enable(clk));
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/*
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* Tick rate is 2.4MHz for Nomadik and 2.4Mhz, 100MHz or 133 MHz
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* for ux500.
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* Use a divide-by-16 counter if the tick rate is more than 32MHz.
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* At 32 MHz, the timer (with 32 bit counter) can be programmed
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* to wake-up at a max 127s a head in time. Dividing a 2.4 MHz timer
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* with 16 gives too low timer resolution.
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*/
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rate = clk_get_rate(clk);
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if (rate > 32000000) {
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rate /= 16;
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clk_prescale = MTU_CRn_PRESCALE_16;
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} else {
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clk_prescale = MTU_CRn_PRESCALE_1;
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}
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/* Cycles for periodic mode */
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nmdk_cycle = DIV_ROUND_CLOSEST(rate, HZ);
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/* Timer 0 is the free running clocksource */
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nmdk_clksrc_reset();
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if (clocksource_mmio_init(mtu_base + MTU_VAL(0), "mtu_0",
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rate, 200, 32, clocksource_mmio_readl_down))
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pr_err("timer: failed to initialize clock source %s\n",
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"mtu_0");
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#ifdef CONFIG_CLKSRC_NOMADIK_MTU_SCHED_CLOCK
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sched_clock_register(nomadik_read_sched_clock, 32, rate);
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#endif
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/* Timer 1 is used for events, register irq and clockevents */
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setup_irq(irq, &nmdk_timer_irq);
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nmdk_clkevt.cpumask = cpumask_of(0);
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nmdk_clkevt.irq = irq;
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clockevents_config_and_register(&nmdk_clkevt, rate, 2, 0xffffffffU);
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mtu_delay_timer.read_current_timer = &nmdk_timer_read_current_timer;
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mtu_delay_timer.freq = rate;
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register_current_timer_delay(&mtu_delay_timer);
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}
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void __init nmdk_timer_init(void __iomem *base, int irq)
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{
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struct clk *clk0, *pclk0;
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pclk0 = clk_get_sys("mtu0", "apb_pclk");
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BUG_ON(IS_ERR(pclk0));
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clk0 = clk_get_sys("mtu0", NULL);
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BUG_ON(IS_ERR(clk0));
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__nmdk_timer_init(base, irq, pclk0, clk0);
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}
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static void __init nmdk_timer_of_init(struct device_node *node)
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{
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struct clk *pclk;
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struct clk *clk;
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void __iomem *base;
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int irq;
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base = of_iomap(node, 0);
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if (!base)
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panic("Can't remap registers");
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pclk = of_clk_get_by_name(node, "apb_pclk");
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if (IS_ERR(pclk))
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panic("could not get apb_pclk");
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clk = of_clk_get_by_name(node, "timclk");
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if (IS_ERR(clk))
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panic("could not get timclk");
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irq = irq_of_parse_and_map(node, 0);
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if (irq <= 0)
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panic("Can't parse IRQ");
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__nmdk_timer_init(base, irq, pclk, clk);
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}
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CLOCKSOURCE_OF_DECLARE(nomadik_mtu, "st,nomadik-mtu",
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nmdk_timer_of_init);
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