diff options
Diffstat (limited to 'drivers/clocksource/cadence_ttc_timer.c')
| -rw-r--r-- | drivers/clocksource/cadence_ttc_timer.c | 543 |
1 files changed, 0 insertions, 543 deletions
diff --git a/drivers/clocksource/cadence_ttc_timer.c b/drivers/clocksource/cadence_ttc_timer.c deleted file mode 100644 index a7eb858a84a0..000000000000 --- a/drivers/clocksource/cadence_ttc_timer.c +++ /dev/null @@ -1,543 +0,0 @@ -/* - * This file contains driver for the Cadence Triple Timer Counter Rev 06 - * - * Copyright (C) 2011-2013 Xilinx - * - * based on arch/mips/kernel/time.c timer driver - * - * This software is licensed under the terms of the GNU General Public - * License version 2, as published by the Free Software Foundation, and - * may be copied, distributed, and modified under those terms. - * - * 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/clk.h> -#include <linux/interrupt.h> -#include <linux/clockchips.h> -#include <linux/clocksource.h> -#include <linux/of_address.h> -#include <linux/of_irq.h> -#include <linux/slab.h> -#include <linux/sched_clock.h> - -/* - * This driver configures the 2 16/32-bit count-up timers as follows: - * - * T1: Timer 1, clocksource for generic timekeeping - * T2: Timer 2, clockevent source for hrtimers - * T3: Timer 3, <unused> - * - * The input frequency to the timer module for emulation is 2.5MHz which is - * common to all the timer channels (T1, T2, and T3). With a pre-scaler of 32, - * the timers are clocked at 78.125KHz (12.8 us resolution). - - * The input frequency to the timer module in silicon is configurable and - * obtained from device tree. The pre-scaler of 32 is used. - */ - -/* - * Timer Register Offset Definitions of Timer 1, Increment base address by 4 - * and use same offsets for Timer 2 - */ -#define TTC_CLK_CNTRL_OFFSET 0x00 /* Clock Control Reg, RW */ -#define TTC_CNT_CNTRL_OFFSET 0x0C /* Counter Control Reg, RW */ -#define TTC_COUNT_VAL_OFFSET 0x18 /* Counter Value Reg, RO */ -#define TTC_INTR_VAL_OFFSET 0x24 /* Interval Count Reg, RW */ -#define TTC_ISR_OFFSET 0x54 /* Interrupt Status Reg, RO */ -#define TTC_IER_OFFSET 0x60 /* Interrupt Enable Reg, RW */ - -#define TTC_CNT_CNTRL_DISABLE_MASK 0x1 - -#define TTC_CLK_CNTRL_CSRC_MASK (1 << 5) /* clock source */ -#define TTC_CLK_CNTRL_PSV_MASK 0x1e -#define TTC_CLK_CNTRL_PSV_SHIFT 1 - -/* - * Setup the timers to use pre-scaling, using a fixed value for now that will - * work across most input frequency, but it may need to be more dynamic - */ -#define PRESCALE_EXPONENT 11 /* 2 ^ PRESCALE_EXPONENT = PRESCALE */ -#define PRESCALE 2048 /* The exponent must match this */ -#define CLK_CNTRL_PRESCALE ((PRESCALE_EXPONENT - 1) << 1) -#define CLK_CNTRL_PRESCALE_EN 1 -#define CNT_CNTRL_RESET (1 << 4) - -#define MAX_F_ERR 50 - -/** - * struct ttc_timer - This definition defines local timer structure - * - * @base_addr: Base address of timer - * @freq: Timer input clock frequency - * @clk: Associated clock source - * @clk_rate_change_nb Notifier block for clock rate changes - */ -struct ttc_timer { - void __iomem *base_addr; - unsigned long freq; - struct clk *clk; - struct notifier_block clk_rate_change_nb; -}; - -#define to_ttc_timer(x) \ - container_of(x, struct ttc_timer, clk_rate_change_nb) - -struct ttc_timer_clocksource { - u32 scale_clk_ctrl_reg_old; - u32 scale_clk_ctrl_reg_new; - struct ttc_timer ttc; - struct clocksource cs; -}; - -#define to_ttc_timer_clksrc(x) \ - container_of(x, struct ttc_timer_clocksource, cs) - -struct ttc_timer_clockevent { - struct ttc_timer ttc; - struct clock_event_device ce; -}; - -#define to_ttc_timer_clkevent(x) \ - container_of(x, struct ttc_timer_clockevent, ce) - -static void __iomem *ttc_sched_clock_val_reg; - -/** - * ttc_set_interval - Set the timer interval value - * - * @timer: Pointer to the timer instance - * @cycles: Timer interval ticks - **/ -static void ttc_set_interval(struct ttc_timer *timer, - unsigned long cycles) -{ - u32 ctrl_reg; - - /* Disable the counter, set the counter value and re-enable counter */ - ctrl_reg = readl_relaxed(timer->base_addr + TTC_CNT_CNTRL_OFFSET); - ctrl_reg |= TTC_CNT_CNTRL_DISABLE_MASK; - writel_relaxed(ctrl_reg, timer->base_addr + TTC_CNT_CNTRL_OFFSET); - - writel_relaxed(cycles, timer->base_addr + TTC_INTR_VAL_OFFSET); - - /* - * Reset the counter (0x10) so that it starts from 0, one-shot - * mode makes this needed for timing to be right. - */ - ctrl_reg |= CNT_CNTRL_RESET; - ctrl_reg &= ~TTC_CNT_CNTRL_DISABLE_MASK; - writel_relaxed(ctrl_reg, timer->base_addr + TTC_CNT_CNTRL_OFFSET); -} - -/** - * ttc_clock_event_interrupt - Clock event timer interrupt handler - * - * @irq: IRQ number of the Timer - * @dev_id: void pointer to the ttc_timer instance - * - * returns: Always IRQ_HANDLED - success - **/ -static irqreturn_t ttc_clock_event_interrupt(int irq, void *dev_id) -{ - struct ttc_timer_clockevent *ttce = dev_id; - struct ttc_timer *timer = &ttce->ttc; - - /* Acknowledge the interrupt and call event handler */ - readl_relaxed(timer->base_addr + TTC_ISR_OFFSET); - - ttce->ce.event_handler(&ttce->ce); - - return IRQ_HANDLED; -} - -/** - * __ttc_clocksource_read - Reads the timer counter register - * - * returns: Current timer counter register value - **/ -static u64 __ttc_clocksource_read(struct clocksource *cs) -{ - struct ttc_timer *timer = &to_ttc_timer_clksrc(cs)->ttc; - - return (u64)readl_relaxed(timer->base_addr + - TTC_COUNT_VAL_OFFSET); -} - -static u64 notrace ttc_sched_clock_read(void) -{ - return readl_relaxed(ttc_sched_clock_val_reg); -} - -/** - * ttc_set_next_event - Sets the time interval for next event - * - * @cycles: Timer interval ticks - * @evt: Address of clock event instance - * - * returns: Always 0 - success - **/ -static int ttc_set_next_event(unsigned long cycles, - struct clock_event_device *evt) -{ - struct ttc_timer_clockevent *ttce = to_ttc_timer_clkevent(evt); - struct ttc_timer *timer = &ttce->ttc; - - ttc_set_interval(timer, cycles); - return 0; -} - -/** - * ttc_set_{shutdown|oneshot|periodic} - Sets the state of timer - * - * @evt: Address of clock event instance - **/ -static int ttc_shutdown(struct clock_event_device *evt) -{ - struct ttc_timer_clockevent *ttce = to_ttc_timer_clkevent(evt); - struct ttc_timer *timer = &ttce->ttc; - u32 ctrl_reg; - - ctrl_reg = readl_relaxed(timer->base_addr + TTC_CNT_CNTRL_OFFSET); - ctrl_reg |= TTC_CNT_CNTRL_DISABLE_MASK; - writel_relaxed(ctrl_reg, timer->base_addr + TTC_CNT_CNTRL_OFFSET); - return 0; -} - -static int ttc_set_periodic(struct clock_event_device *evt) -{ - struct ttc_timer_clockevent *ttce = to_ttc_timer_clkevent(evt); - struct ttc_timer *timer = &ttce->ttc; - - ttc_set_interval(timer, - DIV_ROUND_CLOSEST(ttce->ttc.freq, PRESCALE * HZ)); - return 0; -} - -static int ttc_resume(struct clock_event_device *evt) -{ - struct ttc_timer_clockevent *ttce = to_ttc_timer_clkevent(evt); - struct ttc_timer *timer = &ttce->ttc; - u32 ctrl_reg; - - ctrl_reg = readl_relaxed(timer->base_addr + TTC_CNT_CNTRL_OFFSET); - ctrl_reg &= ~TTC_CNT_CNTRL_DISABLE_MASK; - writel_relaxed(ctrl_reg, timer->base_addr + TTC_CNT_CNTRL_OFFSET); - return 0; -} - -static int ttc_rate_change_clocksource_cb(struct notifier_block *nb, - unsigned long event, void *data) -{ - struct clk_notifier_data *ndata = data; - struct ttc_timer *ttc = to_ttc_timer(nb); - struct ttc_timer_clocksource *ttccs = container_of(ttc, - struct ttc_timer_clocksource, ttc); - - switch (event) { - case PRE_RATE_CHANGE: - { - u32 psv; - unsigned long factor, rate_low, rate_high; - - if (ndata->new_rate > ndata->old_rate) { - factor = DIV_ROUND_CLOSEST(ndata->new_rate, - ndata->old_rate); - rate_low = ndata->old_rate; - rate_high = ndata->new_rate; - } else { - factor = DIV_ROUND_CLOSEST(ndata->old_rate, - ndata->new_rate); - rate_low = ndata->new_rate; - rate_high = ndata->old_rate; - } - - if (!is_power_of_2(factor)) - return NOTIFY_BAD; - - if (abs(rate_high - (factor * rate_low)) > MAX_F_ERR) - return NOTIFY_BAD; - - factor = __ilog2_u32(factor); - - /* - * store timer clock ctrl register so we can restore it in case - * of an abort. - */ - ttccs->scale_clk_ctrl_reg_old = - readl_relaxed(ttccs->ttc.base_addr + - TTC_CLK_CNTRL_OFFSET); - - psv = (ttccs->scale_clk_ctrl_reg_old & - TTC_CLK_CNTRL_PSV_MASK) >> - TTC_CLK_CNTRL_PSV_SHIFT; - if (ndata->new_rate < ndata->old_rate) - psv -= factor; - else - psv += factor; - - /* prescaler within legal range? */ - if (psv & ~(TTC_CLK_CNTRL_PSV_MASK >> TTC_CLK_CNTRL_PSV_SHIFT)) - return NOTIFY_BAD; - - ttccs->scale_clk_ctrl_reg_new = ttccs->scale_clk_ctrl_reg_old & - ~TTC_CLK_CNTRL_PSV_MASK; - ttccs->scale_clk_ctrl_reg_new |= psv << TTC_CLK_CNTRL_PSV_SHIFT; - - - /* scale down: adjust divider in post-change notification */ - if (ndata->new_rate < ndata->old_rate) - return NOTIFY_DONE; - - /* scale up: adjust divider now - before frequency change */ - writel_relaxed(ttccs->scale_clk_ctrl_reg_new, - ttccs->ttc.base_addr + TTC_CLK_CNTRL_OFFSET); - break; - } - case POST_RATE_CHANGE: - /* scale up: pre-change notification did the adjustment */ - if (ndata->new_rate > ndata->old_rate) - return NOTIFY_OK; - - /* scale down: adjust divider now - after frequency change */ - writel_relaxed(ttccs->scale_clk_ctrl_reg_new, - ttccs->ttc.base_addr + TTC_CLK_CNTRL_OFFSET); - break; - - case ABORT_RATE_CHANGE: - /* we have to undo the adjustment in case we scale up */ - if (ndata->new_rate < ndata->old_rate) - return NOTIFY_OK; - - /* restore original register value */ - writel_relaxed(ttccs->scale_clk_ctrl_reg_old, - ttccs->ttc.base_addr + TTC_CLK_CNTRL_OFFSET); - /* fall through */ - default: - return NOTIFY_DONE; - } - - return NOTIFY_DONE; -} - -static int __init ttc_setup_clocksource(struct clk *clk, void __iomem *base, - u32 timer_width) -{ - struct ttc_timer_clocksource *ttccs; - int err; - - ttccs = kzalloc(sizeof(*ttccs), GFP_KERNEL); - if (!ttccs) - return -ENOMEM; - - ttccs->ttc.clk = clk; - - err = clk_prepare_enable(ttccs->ttc.clk); - if (err) { - kfree(ttccs); - return err; - } - - ttccs->ttc.freq = clk_get_rate(ttccs->ttc.clk); - - ttccs->ttc.clk_rate_change_nb.notifier_call = - ttc_rate_change_clocksource_cb; - ttccs->ttc.clk_rate_change_nb.next = NULL; - - err = clk_notifier_register(ttccs->ttc.clk, - &ttccs->ttc.clk_rate_change_nb); - if (err) - pr_warn("Unable to register clock notifier.\n"); - - ttccs->ttc.base_addr = base; - ttccs->cs.name = "ttc_clocksource"; - ttccs->cs.rating = 200; - ttccs->cs.read = __ttc_clocksource_read; - ttccs->cs.mask = CLOCKSOURCE_MASK(timer_width); - ttccs->cs.flags = CLOCK_SOURCE_IS_CONTINUOUS; - - /* - * Setup the clock source counter to be an incrementing counter - * with no interrupt and it rolls over at 0xFFFF. Pre-scale - * it by 32 also. Let it start running now. - */ - writel_relaxed(0x0, ttccs->ttc.base_addr + TTC_IER_OFFSET); - writel_relaxed(CLK_CNTRL_PRESCALE | CLK_CNTRL_PRESCALE_EN, - ttccs->ttc.base_addr + TTC_CLK_CNTRL_OFFSET); - writel_relaxed(CNT_CNTRL_RESET, - ttccs->ttc.base_addr + TTC_CNT_CNTRL_OFFSET); - - err = clocksource_register_hz(&ttccs->cs, ttccs->ttc.freq / PRESCALE); - if (err) { - kfree(ttccs); - return err; - } - - ttc_sched_clock_val_reg = base + TTC_COUNT_VAL_OFFSET; - sched_clock_register(ttc_sched_clock_read, timer_width, - ttccs->ttc.freq / PRESCALE); - - return 0; -} - -static int ttc_rate_change_clockevent_cb(struct notifier_block *nb, - unsigned long event, void *data) -{ - struct clk_notifier_data *ndata = data; - struct ttc_timer *ttc = to_ttc_timer(nb); - struct ttc_timer_clockevent *ttcce = container_of(ttc, - struct ttc_timer_clockevent, ttc); - - switch (event) { - case POST_RATE_CHANGE: - /* update cached frequency */ - ttc->freq = ndata->new_rate; - - clockevents_update_freq(&ttcce->ce, ndata->new_rate / PRESCALE); - - /* fall through */ - case PRE_RATE_CHANGE: - case ABORT_RATE_CHANGE: - default: - return NOTIFY_DONE; - } -} - -static int __init ttc_setup_clockevent(struct clk *clk, - void __iomem *base, u32 irq) -{ - struct ttc_timer_clockevent *ttcce; - int err; - - ttcce = kzalloc(sizeof(*ttcce), GFP_KERNEL); - if (!ttcce) - return -ENOMEM; - - ttcce->ttc.clk = clk; - - err = clk_prepare_enable(ttcce->ttc.clk); - if (err) - goto out_kfree; - - ttcce->ttc.clk_rate_change_nb.notifier_call = - ttc_rate_change_clockevent_cb; - ttcce->ttc.clk_rate_change_nb.next = NULL; - - err = clk_notifier_register(ttcce->ttc.clk, - &ttcce->ttc.clk_rate_change_nb); - if (err) { - pr_warn("Unable to register clock notifier.\n"); - goto out_kfree; - } - - ttcce->ttc.freq = clk_get_rate(ttcce->ttc.clk); - - ttcce->ttc.base_addr = base; - ttcce->ce.name = "ttc_clockevent"; - ttcce->ce.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT; - ttcce->ce.set_next_event = ttc_set_next_event; - ttcce->ce.set_state_shutdown = ttc_shutdown; - ttcce->ce.set_state_periodic = ttc_set_periodic; - ttcce->ce.set_state_oneshot = ttc_shutdown; - ttcce->ce.tick_resume = ttc_resume; - ttcce->ce.rating = 200; - ttcce->ce.irq = irq; - ttcce->ce.cpumask = cpu_possible_mask; - - /* - * Setup the clock event timer to be an interval timer which - * is prescaled by 32 using the interval interrupt. Leave it - * disabled for now. - */ - writel_relaxed(0x23, ttcce->ttc.base_addr + TTC_CNT_CNTRL_OFFSET); - writel_relaxed(CLK_CNTRL_PRESCALE | CLK_CNTRL_PRESCALE_EN, - ttcce->ttc.base_addr + TTC_CLK_CNTRL_OFFSET); - writel_relaxed(0x1, ttcce->ttc.base_addr + TTC_IER_OFFSET); - - err = request_irq(irq, ttc_clock_event_interrupt, - IRQF_TIMER, ttcce->ce.name, ttcce); - if (err) - goto out_kfree; - - clockevents_config_and_register(&ttcce->ce, - ttcce->ttc.freq / PRESCALE, 1, 0xfffe); - - return 0; - -out_kfree: - kfree(ttcce); - return err; -} - -/** - * ttc_timer_init - Initialize the timer - * - * Initializes the timer hardware and register the clock source and clock event - * timers with Linux kernal timer framework - */ -static int __init ttc_timer_init(struct device_node *timer) -{ - unsigned int irq; - void __iomem *timer_baseaddr; - struct clk *clk_cs, *clk_ce; - static int initialized; - int clksel, ret; - u32 timer_width = 16; - - if (initialized) - return 0; - - initialized = 1; - - /* - * Get the 1st Triple Timer Counter (TTC) block from the device tree - * and use it. Note that the event timer uses the interrupt and it's the - * 2nd TTC hence the irq_of_parse_and_map(,1) - */ - timer_baseaddr = of_iomap(timer, 0); - if (!timer_baseaddr) { - pr_err("ERROR: invalid timer base address\n"); - return -ENXIO; - } - - irq = irq_of_parse_and_map(timer, 1); - if (irq <= 0) { - pr_err("ERROR: invalid interrupt number\n"); - return -EINVAL; - } - - of_property_read_u32(timer, "timer-width", &timer_width); - - clksel = readl_relaxed(timer_baseaddr + TTC_CLK_CNTRL_OFFSET); - clksel = !!(clksel & TTC_CLK_CNTRL_CSRC_MASK); - clk_cs = of_clk_get(timer, clksel); - if (IS_ERR(clk_cs)) { - pr_err("ERROR: timer input clock not found\n"); - return PTR_ERR(clk_cs); - } - - clksel = readl_relaxed(timer_baseaddr + 4 + TTC_CLK_CNTRL_OFFSET); - clksel = !!(clksel & TTC_CLK_CNTRL_CSRC_MASK); - clk_ce = of_clk_get(timer, clksel); - if (IS_ERR(clk_ce)) { - pr_err("ERROR: timer input clock not found\n"); - return PTR_ERR(clk_ce); - } - - ret = ttc_setup_clocksource(clk_cs, timer_baseaddr, timer_width); - if (ret) - return ret; - - ret = ttc_setup_clockevent(clk_ce, timer_baseaddr + 4, irq); - if (ret) - return ret; - - pr_info("%s #0 at %p, irq=%d\n", timer->name, timer_baseaddr, irq); - - return 0; -} - -TIMER_OF_DECLARE(ttc, "cdns,ttc", ttc_timer_init); |