/* * Copyright (C) 2000-2001 Deep Blue Solutions * Copyright (C) 2002 Shane Nay (shane@minirl.com) * Copyright (C) 2006-2007 Pavel Pisa (ppisa@pikron.com) * Copyright (C) 2008 Juergen Beisert (kernel@pengutronix.de) * Copyright (C) 2010 Freescale Semiconductor, Inc. All Rights Reserved. * * 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. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, * MA 02110-1301, USA. */ #include <linux/err.h> #include <linux/interrupt.h> #include <linux/irq.h> #include <linux/clockchips.h> #include <linux/clk.h> #include <linux/of.h> #include <linux/of_address.h> #include <linux/of_irq.h> #include <linux/stmp_device.h> #include <linux/sched_clock.h> /* * There are 2 versions of the timrot on Freescale MXS-based SoCs. * The v1 on MX23 only gets 16 bits counter, while v2 on MX28 * extends the counter to 32 bits. * * The implementation uses two timers, one for clock_event and * another for clocksource. MX28 uses timrot 0 and 1, while MX23 * uses 0 and 2. */ #define MX23_TIMROT_VERSION_OFFSET 0x0a0 #define MX28_TIMROT_VERSION_OFFSET 0x120 #define BP_TIMROT_MAJOR_VERSION 24 #define BV_TIMROT_VERSION_1 0x01 #define BV_TIMROT_VERSION_2 0x02 #define timrot_is_v1() (timrot_major_version == BV_TIMROT_VERSION_1) /* * There are 4 registers for each timrotv2 instance, and 2 registers * for each timrotv1. So address step 0x40 in macros below strides * one instance of timrotv2 while two instances of timrotv1. * * As the result, HW_TIMROT_XXXn(1) defines the address of timrot1 * on MX28 while timrot2 on MX23. */ /* common between v1 and v2 */ #define HW_TIMROT_ROTCTRL 0x00 #define HW_TIMROT_TIMCTRLn(n) (0x20 + (n) * 0x40) /* v1 only */ #define HW_TIMROT_TIMCOUNTn(n) (0x30 + (n) * 0x40) /* v2 only */ #define HW_TIMROT_RUNNING_COUNTn(n) (0x30 + (n) * 0x40) #define HW_TIMROT_FIXED_COUNTn(n) (0x40 + (n) * 0x40) #define BM_TIMROT_TIMCTRLn_RELOAD (1 << 6) #define BM_TIMROT_TIMCTRLn_UPDATE (1 << 7) #define BM_TIMROT_TIMCTRLn_IRQ_EN (1 << 14) #define BM_TIMROT_TIMCTRLn_IRQ (1 << 15) #define BP_TIMROT_TIMCTRLn_SELECT 0 #define BV_TIMROTv1_TIMCTRLn_SELECT__32KHZ_XTAL 0x8 #define BV_TIMROTv2_TIMCTRLn_SELECT__32KHZ_XTAL 0xb #define BV_TIMROTv2_TIMCTRLn_SELECT__TICK_ALWAYS 0xf static struct clock_event_device mxs_clockevent_device; static void __iomem *mxs_timrot_base; static u32 timrot_major_version; static inline void timrot_irq_disable(void) { __raw_writel(BM_TIMROT_TIMCTRLn_IRQ_EN, mxs_timrot_base + HW_TIMROT_TIMCTRLn(0) + STMP_OFFSET_REG_CLR); } static inline void timrot_irq_enable(void) { __raw_writel(BM_TIMROT_TIMCTRLn_IRQ_EN, mxs_timrot_base + HW_TIMROT_TIMCTRLn(0) + STMP_OFFSET_REG_SET); } static void timrot_irq_acknowledge(void) { __raw_writel(BM_TIMROT_TIMCTRLn_IRQ, mxs_timrot_base + HW_TIMROT_TIMCTRLn(0) + STMP_OFFSET_REG_CLR); } static u64 timrotv1_get_cycles(struct clocksource *cs) { return ~((__raw_readl(mxs_timrot_base + HW_TIMROT_TIMCOUNTn(1)) & 0xffff0000) >> 16); } static int timrotv1_set_next_event(unsigned long evt, struct clock_event_device *dev) { /* timrot decrements the count */ __raw_writel(evt, mxs_timrot_base + HW_TIMROT_TIMCOUNTn(0)); return 0; } static int timrotv2_set_next_event(unsigned long evt, struct clock_event_device *dev) { /* timrot decrements the count */ __raw_writel(evt, mxs_timrot_base + HW_TIMROT_FIXED_COUNTn(0)); return 0; } static irqreturn_t mxs_timer_interrupt(int irq, void *dev_id) { struct clock_event_device *evt = dev_id; timrot_irq_acknowledge(); evt->event_handler(evt); return IRQ_HANDLED; } static struct irqaction mxs_timer_irq = { .name = "MXS Timer Tick", .dev_id = &mxs_clockevent_device, .flags = IRQF_TIMER | IRQF_IRQPOLL, .handler = mxs_timer_interrupt, }; static void mxs_irq_clear(char *state) { /* Disable interrupt in timer module */ timrot_irq_disable(); /* Set event time into the furthest future */ if (timrot_is_v1()) __raw_writel(0xffff, mxs_timrot_base + HW_TIMROT_TIMCOUNTn(1)); else __raw_writel(0xffffffff, mxs_timrot_base + HW_TIMROT_FIXED_COUNTn(1)); /* Clear pending interrupt */ timrot_irq_acknowledge(); #ifdef DEBUG pr_info("%s: changing mode to %s\n", __func__, state) #endif /* DEBUG */ } static int mxs_shutdown(struct clock_event_device *evt) { mxs_irq_clear("shutdown"); return 0; } static int mxs_set_oneshot(struct clock_event_device *evt) { if (clockevent_state_oneshot(evt)) mxs_irq_clear("oneshot"); timrot_irq_enable(); return 0; } static struct clock_event_device mxs_clockevent_device = { .name = "mxs_timrot", .features = CLOCK_EVT_FEAT_ONESHOT, .set_state_shutdown = mxs_shutdown, .set_state_oneshot = mxs_set_oneshot, .tick_resume = mxs_shutdown, .set_next_event = timrotv2_set_next_event, .rating = 200, }; static int __init mxs_clockevent_init(struct clk *timer_clk) { if (timrot_is_v1()) mxs_clockevent_device.set_next_event = timrotv1_set_next_event; mxs_clockevent_device.cpumask = cpumask_of(0); clockevents_config_and_register(&mxs_clockevent_device, clk_get_rate(timer_clk), timrot_is_v1() ? 0xf : 0x2, timrot_is_v1() ? 0xfffe : 0xfffffffe); return 0; } static struct clocksource clocksource_mxs = { .name = "mxs_timer", .rating = 200, .read = timrotv1_get_cycles, .mask = CLOCKSOURCE_MASK(16), .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; static u64 notrace mxs_read_sched_clock_v2(void) { return ~readl_relaxed(mxs_timrot_base + HW_TIMROT_RUNNING_COUNTn(1)); } static int __init mxs_clocksource_init(struct clk *timer_clk) { unsigned int c = clk_get_rate(timer_clk); if (timrot_is_v1()) clocksource_register_hz(&clocksource_mxs, c); else { clocksource_mmio_init(mxs_timrot_base + HW_TIMROT_RUNNING_COUNTn(1), "mxs_timer", c, 200, 32, clocksource_mmio_readl_down); sched_clock_register(mxs_read_sched_clock_v2, 32, c); } return 0; } static int __init mxs_timer_init(struct device_node *np) { struct clk *timer_clk; int irq, ret; mxs_timrot_base = of_iomap(np, 0); WARN_ON(!mxs_timrot_base); timer_clk = of_clk_get(np, 0); if (IS_ERR(timer_clk)) { pr_err("%s: failed to get clk\n", __func__); return PTR_ERR(timer_clk); } ret = clk_prepare_enable(timer_clk); if (ret) return ret; /* * Initialize timers to a known state */ stmp_reset_block(mxs_timrot_base + HW_TIMROT_ROTCTRL); /* get timrot version */ timrot_major_version = __raw_readl(mxs_timrot_base + (of_device_is_compatible(np, "fsl,imx23-timrot") ? MX23_TIMROT_VERSION_OFFSET : MX28_TIMROT_VERSION_OFFSET)); timrot_major_version >>= BP_TIMROT_MAJOR_VERSION; /* one for clock_event */ __raw_writel((timrot_is_v1() ? BV_TIMROTv1_TIMCTRLn_SELECT__32KHZ_XTAL : BV_TIMROTv2_TIMCTRLn_SELECT__TICK_ALWAYS) | BM_TIMROT_TIMCTRLn_UPDATE | BM_TIMROT_TIMCTRLn_IRQ_EN, mxs_timrot_base + HW_TIMROT_TIMCTRLn(0)); /* another for clocksource */ __raw_writel((timrot_is_v1() ? BV_TIMROTv1_TIMCTRLn_SELECT__32KHZ_XTAL : BV_TIMROTv2_TIMCTRLn_SELECT__TICK_ALWAYS) | BM_TIMROT_TIMCTRLn_RELOAD, mxs_timrot_base + HW_TIMROT_TIMCTRLn(1)); /* set clocksource timer fixed count to the maximum */ if (timrot_is_v1()) __raw_writel(0xffff, mxs_timrot_base + HW_TIMROT_TIMCOUNTn(1)); else __raw_writel(0xffffffff, mxs_timrot_base + HW_TIMROT_FIXED_COUNTn(1)); /* init and register the timer to the framework */ ret = mxs_clocksource_init(timer_clk); if (ret) return ret; ret = mxs_clockevent_init(timer_clk); if (ret) return ret; /* Make irqs happen */ irq = irq_of_parse_and_map(np, 0); if (irq <= 0) return -EINVAL; return setup_irq(irq, &mxs_timer_irq); } TIMER_OF_DECLARE(mxs, "fsl,timrot", mxs_timer_init);