diff options
Diffstat (limited to 'kernel/arch/arm/mach-lpc32xx/timer.c')
| -rw-r--r-- | kernel/arch/arm/mach-lpc32xx/timer.c | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/kernel/arch/arm/mach-lpc32xx/timer.c b/kernel/arch/arm/mach-lpc32xx/timer.c new file mode 100644 index 000000000..4e5837299 --- /dev/null +++ b/kernel/arch/arm/mach-lpc32xx/timer.c @@ -0,0 +1,156 @@ +/* + * arch/arm/mach-lpc32xx/timer.c + * + * Author: Kevin Wells <kevin.wells@nxp.com> + * + * Copyright (C) 2009 - 2010 NXP Semiconductors + * Copyright (C) 2009 Fontys University of Applied Sciences, Eindhoven + * Ed Schouten <e.schouten@fontys.nl> + * Laurens Timmermans <l.timmermans@fontys.nl> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/time.h> +#include <linux/err.h> +#include <linux/clockchips.h> + +#include <asm/mach/time.h> + +#include <mach/hardware.h> +#include <mach/platform.h> +#include "common.h" + +static int lpc32xx_clkevt_next_event(unsigned long delta, + struct clock_event_device *dev) +{ + __raw_writel(LPC32XX_TIMER_CNTR_TCR_RESET, + LPC32XX_TIMER_TCR(LPC32XX_TIMER0_BASE)); + __raw_writel(delta, LPC32XX_TIMER_PR(LPC32XX_TIMER0_BASE)); + __raw_writel(LPC32XX_TIMER_CNTR_TCR_EN, + LPC32XX_TIMER_TCR(LPC32XX_TIMER0_BASE)); + + return 0; +} + +static void lpc32xx_clkevt_mode(enum clock_event_mode mode, + struct clock_event_device *dev) +{ + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + WARN_ON(1); + break; + + case CLOCK_EVT_MODE_ONESHOT: + case CLOCK_EVT_MODE_SHUTDOWN: + /* + * Disable the timer. When using oneshot, we must also + * disable the timer to wait for the first call to + * set_next_event(). + */ + __raw_writel(0, LPC32XX_TIMER_TCR(LPC32XX_TIMER0_BASE)); + break; + + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_RESUME: + break; + } +} + +static struct clock_event_device lpc32xx_clkevt = { + .name = "lpc32xx_clkevt", + .features = CLOCK_EVT_FEAT_ONESHOT, + .rating = 300, + .set_next_event = lpc32xx_clkevt_next_event, + .set_mode = lpc32xx_clkevt_mode, +}; + +static irqreturn_t lpc32xx_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evt = &lpc32xx_clkevt; + + /* Clear match */ + __raw_writel(LPC32XX_TIMER_CNTR_MTCH_BIT(0), + LPC32XX_TIMER_IR(LPC32XX_TIMER0_BASE)); + + evt->event_handler(evt); + + return IRQ_HANDLED; +} + +static struct irqaction lpc32xx_timer_irq = { + .name = "LPC32XX Timer Tick", + .flags = IRQF_TIMER | IRQF_IRQPOLL, + .handler = lpc32xx_timer_interrupt, +}; + +/* + * The clock management driver isn't initialized at this point, so the + * clocks need to be enabled here manually and then tagged as used in + * the clock driver initialization + */ +void __init lpc32xx_timer_init(void) +{ + u32 clkrate, pllreg; + + /* Enable timer clock */ + __raw_writel(LPC32XX_CLKPWR_TMRPWMCLK_TIMER0_EN | + LPC32XX_CLKPWR_TMRPWMCLK_TIMER1_EN, + LPC32XX_CLKPWR_TIMERS_PWMS_CLK_CTRL_1); + + /* + * The clock driver isn't initialized at this point. So determine if + * the SYSCLK is driven from the PLL397 or main oscillator and then use + * it to compute the PLL frequency and the PCLK divider to get the base + * timer rates. This rate is needed to compute the tick rate. + */ + if (clk_is_sysclk_mainosc() != 0) + clkrate = LPC32XX_MAIN_OSC_FREQ; + else + clkrate = 397 * LPC32XX_CLOCK_OSC_FREQ; + + /* Get ARM HCLKPLL register and convert it into a frequency */ + pllreg = __raw_readl(LPC32XX_CLKPWR_HCLKPLL_CTRL) & 0x1FFFF; + clkrate = clk_get_pllrate_from_reg(clkrate, pllreg); + + /* Get PCLK divider and divide ARM PLL clock by it to get timer rate */ + clkrate = clkrate / clk_get_pclk_div(); + + /* Initial timer setup */ + __raw_writel(0, LPC32XX_TIMER_TCR(LPC32XX_TIMER0_BASE)); + __raw_writel(LPC32XX_TIMER_CNTR_MTCH_BIT(0), + LPC32XX_TIMER_IR(LPC32XX_TIMER0_BASE)); + __raw_writel(1, LPC32XX_TIMER_MR0(LPC32XX_TIMER0_BASE)); + __raw_writel(LPC32XX_TIMER_CNTR_MCR_MTCH(0) | + LPC32XX_TIMER_CNTR_MCR_STOP(0) | + LPC32XX_TIMER_CNTR_MCR_RESET(0), + LPC32XX_TIMER_MCR(LPC32XX_TIMER0_BASE)); + + /* Setup tick interrupt */ + setup_irq(IRQ_LPC32XX_TIMER0, &lpc32xx_timer_irq); + + /* Setup the clockevent structure. */ + lpc32xx_clkevt.cpumask = cpumask_of(0); + clockevents_config_and_register(&lpc32xx_clkevt, clkrate, 1, -1); + + /* Use timer1 as clock source. */ + __raw_writel(LPC32XX_TIMER_CNTR_TCR_RESET, + LPC32XX_TIMER_TCR(LPC32XX_TIMER1_BASE)); + __raw_writel(0, LPC32XX_TIMER_PR(LPC32XX_TIMER1_BASE)); + __raw_writel(0, LPC32XX_TIMER_MCR(LPC32XX_TIMER1_BASE)); + __raw_writel(LPC32XX_TIMER_CNTR_TCR_EN, + LPC32XX_TIMER_TCR(LPC32XX_TIMER1_BASE)); + + clocksource_mmio_init(LPC32XX_TIMER_TC(LPC32XX_TIMER1_BASE), + "lpc32xx_clksrc", clkrate, 300, 32, clocksource_mmio_readl_up); +} |