diff options
Diffstat (limited to 'drivers/clocksource/timer-u300.c')
| -rw-r--r-- | drivers/clocksource/timer-u300.c | 457 |
1 files changed, 457 insertions, 0 deletions
diff --git a/drivers/clocksource/timer-u300.c b/drivers/clocksource/timer-u300.c new file mode 100644 index 000000000..37cba8dfd --- /dev/null +++ b/drivers/clocksource/timer-u300.c @@ -0,0 +1,457 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2007-2009 ST-Ericsson AB + * Timer COH 901 328, runs the OS timer interrupt. + * Author: Linus Walleij <linus.walleij@stericsson.com> + */ +#include <linux/interrupt.h> +#include <linux/time.h> +#include <linux/timex.h> +#include <linux/clockchips.h> +#include <linux/clocksource.h> +#include <linux/types.h> +#include <linux/io.h> +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/irq.h> +#include <linux/delay.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/sched_clock.h> + +/* Generic stuff */ +#include <asm/mach/map.h> +#include <asm/mach/time.h> + +/* + * APP side special timer registers + * This timer contains four timers which can fire an interrupt each. + * OS (operating system) timer @ 32768 Hz + * DD (device driver) timer @ 1 kHz + * GP1 (general purpose 1) timer @ 1MHz + * GP2 (general purpose 2) timer @ 1MHz + */ + +/* Reset OS Timer 32bit (-/W) */ +#define U300_TIMER_APP_ROST (0x0000) +#define U300_TIMER_APP_ROST_TIMER_RESET (0x00000000) +/* Enable OS Timer 32bit (-/W) */ +#define U300_TIMER_APP_EOST (0x0004) +#define U300_TIMER_APP_EOST_TIMER_ENABLE (0x00000000) +/* Disable OS Timer 32bit (-/W) */ +#define U300_TIMER_APP_DOST (0x0008) +#define U300_TIMER_APP_DOST_TIMER_DISABLE (0x00000000) +/* OS Timer Mode Register 32bit (-/W) */ +#define U300_TIMER_APP_SOSTM (0x000c) +#define U300_TIMER_APP_SOSTM_MODE_CONTINUOUS (0x00000000) +#define U300_TIMER_APP_SOSTM_MODE_ONE_SHOT (0x00000001) +/* OS Timer Status Register 32bit (R/-) */ +#define U300_TIMER_APP_OSTS (0x0010) +#define U300_TIMER_APP_OSTS_TIMER_STATE_MASK (0x0000000F) +#define U300_TIMER_APP_OSTS_TIMER_STATE_IDLE (0x00000001) +#define U300_TIMER_APP_OSTS_TIMER_STATE_ACTIVE (0x00000002) +#define U300_TIMER_APP_OSTS_ENABLE_IND (0x00000010) +#define U300_TIMER_APP_OSTS_MODE_MASK (0x00000020) +#define U300_TIMER_APP_OSTS_MODE_CONTINUOUS (0x00000000) +#define U300_TIMER_APP_OSTS_MODE_ONE_SHOT (0x00000020) +#define U300_TIMER_APP_OSTS_IRQ_ENABLED_IND (0x00000040) +#define U300_TIMER_APP_OSTS_IRQ_PENDING_IND (0x00000080) +/* OS Timer Current Count Register 32bit (R/-) */ +#define U300_TIMER_APP_OSTCC (0x0014) +/* OS Timer Terminal Count Register 32bit (R/W) */ +#define U300_TIMER_APP_OSTTC (0x0018) +/* OS Timer Interrupt Enable Register 32bit (-/W) */ +#define U300_TIMER_APP_OSTIE (0x001c) +#define U300_TIMER_APP_OSTIE_IRQ_DISABLE (0x00000000) +#define U300_TIMER_APP_OSTIE_IRQ_ENABLE (0x00000001) +/* OS Timer Interrupt Acknowledge Register 32bit (-/W) */ +#define U300_TIMER_APP_OSTIA (0x0020) +#define U300_TIMER_APP_OSTIA_IRQ_ACK (0x00000080) + +/* Reset DD Timer 32bit (-/W) */ +#define U300_TIMER_APP_RDDT (0x0040) +#define U300_TIMER_APP_RDDT_TIMER_RESET (0x00000000) +/* Enable DD Timer 32bit (-/W) */ +#define U300_TIMER_APP_EDDT (0x0044) +#define U300_TIMER_APP_EDDT_TIMER_ENABLE (0x00000000) +/* Disable DD Timer 32bit (-/W) */ +#define U300_TIMER_APP_DDDT (0x0048) +#define U300_TIMER_APP_DDDT_TIMER_DISABLE (0x00000000) +/* DD Timer Mode Register 32bit (-/W) */ +#define U300_TIMER_APP_SDDTM (0x004c) +#define U300_TIMER_APP_SDDTM_MODE_CONTINUOUS (0x00000000) +#define U300_TIMER_APP_SDDTM_MODE_ONE_SHOT (0x00000001) +/* DD Timer Status Register 32bit (R/-) */ +#define U300_TIMER_APP_DDTS (0x0050) +#define U300_TIMER_APP_DDTS_TIMER_STATE_MASK (0x0000000F) +#define U300_TIMER_APP_DDTS_TIMER_STATE_IDLE (0x00000001) +#define U300_TIMER_APP_DDTS_TIMER_STATE_ACTIVE (0x00000002) +#define U300_TIMER_APP_DDTS_ENABLE_IND (0x00000010) +#define U300_TIMER_APP_DDTS_MODE_MASK (0x00000020) +#define U300_TIMER_APP_DDTS_MODE_CONTINUOUS (0x00000000) +#define U300_TIMER_APP_DDTS_MODE_ONE_SHOT (0x00000020) +#define U300_TIMER_APP_DDTS_IRQ_ENABLED_IND (0x00000040) +#define U300_TIMER_APP_DDTS_IRQ_PENDING_IND (0x00000080) +/* DD Timer Current Count Register 32bit (R/-) */ +#define U300_TIMER_APP_DDTCC (0x0054) +/* DD Timer Terminal Count Register 32bit (R/W) */ +#define U300_TIMER_APP_DDTTC (0x0058) +/* DD Timer Interrupt Enable Register 32bit (-/W) */ +#define U300_TIMER_APP_DDTIE (0x005c) +#define U300_TIMER_APP_DDTIE_IRQ_DISABLE (0x00000000) +#define U300_TIMER_APP_DDTIE_IRQ_ENABLE (0x00000001) +/* DD Timer Interrupt Acknowledge Register 32bit (-/W) */ +#define U300_TIMER_APP_DDTIA (0x0060) +#define U300_TIMER_APP_DDTIA_IRQ_ACK (0x00000080) + +/* Reset GP1 Timer 32bit (-/W) */ +#define U300_TIMER_APP_RGPT1 (0x0080) +#define U300_TIMER_APP_RGPT1_TIMER_RESET (0x00000000) +/* Enable GP1 Timer 32bit (-/W) */ +#define U300_TIMER_APP_EGPT1 (0x0084) +#define U300_TIMER_APP_EGPT1_TIMER_ENABLE (0x00000000) +/* Disable GP1 Timer 32bit (-/W) */ +#define U300_TIMER_APP_DGPT1 (0x0088) +#define U300_TIMER_APP_DGPT1_TIMER_DISABLE (0x00000000) +/* GP1 Timer Mode Register 32bit (-/W) */ +#define U300_TIMER_APP_SGPT1M (0x008c) +#define U300_TIMER_APP_SGPT1M_MODE_CONTINUOUS (0x00000000) +#define U300_TIMER_APP_SGPT1M_MODE_ONE_SHOT (0x00000001) +/* GP1 Timer Status Register 32bit (R/-) */ +#define U300_TIMER_APP_GPT1S (0x0090) +#define U300_TIMER_APP_GPT1S_TIMER_STATE_MASK (0x0000000F) +#define U300_TIMER_APP_GPT1S_TIMER_STATE_IDLE (0x00000001) +#define U300_TIMER_APP_GPT1S_TIMER_STATE_ACTIVE (0x00000002) +#define U300_TIMER_APP_GPT1S_ENABLE_IND (0x00000010) +#define U300_TIMER_APP_GPT1S_MODE_MASK (0x00000020) +#define U300_TIMER_APP_GPT1S_MODE_CONTINUOUS (0x00000000) +#define U300_TIMER_APP_GPT1S_MODE_ONE_SHOT (0x00000020) +#define U300_TIMER_APP_GPT1S_IRQ_ENABLED_IND (0x00000040) +#define U300_TIMER_APP_GPT1S_IRQ_PENDING_IND (0x00000080) +/* GP1 Timer Current Count Register 32bit (R/-) */ +#define U300_TIMER_APP_GPT1CC (0x0094) +/* GP1 Timer Terminal Count Register 32bit (R/W) */ +#define U300_TIMER_APP_GPT1TC (0x0098) +/* GP1 Timer Interrupt Enable Register 32bit (-/W) */ +#define U300_TIMER_APP_GPT1IE (0x009c) +#define U300_TIMER_APP_GPT1IE_IRQ_DISABLE (0x00000000) +#define U300_TIMER_APP_GPT1IE_IRQ_ENABLE (0x00000001) +/* GP1 Timer Interrupt Acknowledge Register 32bit (-/W) */ +#define U300_TIMER_APP_GPT1IA (0x00a0) +#define U300_TIMER_APP_GPT1IA_IRQ_ACK (0x00000080) + +/* Reset GP2 Timer 32bit (-/W) */ +#define U300_TIMER_APP_RGPT2 (0x00c0) +#define U300_TIMER_APP_RGPT2_TIMER_RESET (0x00000000) +/* Enable GP2 Timer 32bit (-/W) */ +#define U300_TIMER_APP_EGPT2 (0x00c4) +#define U300_TIMER_APP_EGPT2_TIMER_ENABLE (0x00000000) +/* Disable GP2 Timer 32bit (-/W) */ +#define U300_TIMER_APP_DGPT2 (0x00c8) +#define U300_TIMER_APP_DGPT2_TIMER_DISABLE (0x00000000) +/* GP2 Timer Mode Register 32bit (-/W) */ +#define U300_TIMER_APP_SGPT2M (0x00cc) +#define U300_TIMER_APP_SGPT2M_MODE_CONTINUOUS (0x00000000) +#define U300_TIMER_APP_SGPT2M_MODE_ONE_SHOT (0x00000001) +/* GP2 Timer Status Register 32bit (R/-) */ +#define U300_TIMER_APP_GPT2S (0x00d0) +#define U300_TIMER_APP_GPT2S_TIMER_STATE_MASK (0x0000000F) +#define U300_TIMER_APP_GPT2S_TIMER_STATE_IDLE (0x00000001) +#define U300_TIMER_APP_GPT2S_TIMER_STATE_ACTIVE (0x00000002) +#define U300_TIMER_APP_GPT2S_ENABLE_IND (0x00000010) +#define U300_TIMER_APP_GPT2S_MODE_MASK (0x00000020) +#define U300_TIMER_APP_GPT2S_MODE_CONTINUOUS (0x00000000) +#define U300_TIMER_APP_GPT2S_MODE_ONE_SHOT (0x00000020) +#define U300_TIMER_APP_GPT2S_IRQ_ENABLED_IND (0x00000040) +#define U300_TIMER_APP_GPT2S_IRQ_PENDING_IND (0x00000080) +/* GP2 Timer Current Count Register 32bit (R/-) */ +#define U300_TIMER_APP_GPT2CC (0x00d4) +/* GP2 Timer Terminal Count Register 32bit (R/W) */ +#define U300_TIMER_APP_GPT2TC (0x00d8) +/* GP2 Timer Interrupt Enable Register 32bit (-/W) */ +#define U300_TIMER_APP_GPT2IE (0x00dc) +#define U300_TIMER_APP_GPT2IE_IRQ_DISABLE (0x00000000) +#define U300_TIMER_APP_GPT2IE_IRQ_ENABLE (0x00000001) +/* GP2 Timer Interrupt Acknowledge Register 32bit (-/W) */ +#define U300_TIMER_APP_GPT2IA (0x00e0) +#define U300_TIMER_APP_GPT2IA_IRQ_ACK (0x00000080) + +/* Clock request control register - all four timers */ +#define U300_TIMER_APP_CRC (0x100) +#define U300_TIMER_APP_CRC_CLOCK_REQUEST_ENABLE (0x00000001) + +static void __iomem *u300_timer_base; + +struct u300_clockevent_data { + struct clock_event_device cevd; + unsigned ticks_per_jiffy; +}; + +static int u300_shutdown(struct clock_event_device *evt) +{ + /* Disable interrupts on GP1 */ + writel(U300_TIMER_APP_GPT1IE_IRQ_DISABLE, + u300_timer_base + U300_TIMER_APP_GPT1IE); + /* Disable GP1 */ + writel(U300_TIMER_APP_DGPT1_TIMER_DISABLE, + u300_timer_base + U300_TIMER_APP_DGPT1); + return 0; +} + +/* + * If we have oneshot timer active, the oneshot scheduling function + * u300_set_next_event() is called immediately after. + */ +static int u300_set_oneshot(struct clock_event_device *evt) +{ + /* Just return; here? */ + /* + * The actual event will be programmed by the next event hook, + * so we just set a dummy value somewhere at the end of the + * universe here. + */ + /* Disable interrupts on GPT1 */ + writel(U300_TIMER_APP_GPT1IE_IRQ_DISABLE, + u300_timer_base + U300_TIMER_APP_GPT1IE); + /* Disable GP1 while we're reprogramming it. */ + writel(U300_TIMER_APP_DGPT1_TIMER_DISABLE, + u300_timer_base + U300_TIMER_APP_DGPT1); + /* + * Expire far in the future, u300_set_next_event() will be + * called soon... + */ + writel(0xFFFFFFFF, u300_timer_base + U300_TIMER_APP_GPT1TC); + /* We run one shot per tick here! */ + writel(U300_TIMER_APP_SGPT1M_MODE_ONE_SHOT, + u300_timer_base + U300_TIMER_APP_SGPT1M); + /* Enable interrupts for this timer */ + writel(U300_TIMER_APP_GPT1IE_IRQ_ENABLE, + u300_timer_base + U300_TIMER_APP_GPT1IE); + /* Enable timer */ + writel(U300_TIMER_APP_EGPT1_TIMER_ENABLE, + u300_timer_base + U300_TIMER_APP_EGPT1); + return 0; +} + +static int u300_set_periodic(struct clock_event_device *evt) +{ + struct u300_clockevent_data *cevdata = + container_of(evt, struct u300_clockevent_data, cevd); + + /* Disable interrupts on GPT1 */ + writel(U300_TIMER_APP_GPT1IE_IRQ_DISABLE, + u300_timer_base + U300_TIMER_APP_GPT1IE); + /* Disable GP1 while we're reprogramming it. */ + writel(U300_TIMER_APP_DGPT1_TIMER_DISABLE, + u300_timer_base + U300_TIMER_APP_DGPT1); + /* + * Set the periodic mode to a certain number of ticks per + * jiffy. + */ + writel(cevdata->ticks_per_jiffy, + u300_timer_base + U300_TIMER_APP_GPT1TC); + /* + * Set continuous mode, so the timer keeps triggering + * interrupts. + */ + writel(U300_TIMER_APP_SGPT1M_MODE_CONTINUOUS, + u300_timer_base + U300_TIMER_APP_SGPT1M); + /* Enable timer interrupts */ + writel(U300_TIMER_APP_GPT1IE_IRQ_ENABLE, + u300_timer_base + U300_TIMER_APP_GPT1IE); + /* Then enable the OS timer again */ + writel(U300_TIMER_APP_EGPT1_TIMER_ENABLE, + u300_timer_base + U300_TIMER_APP_EGPT1); + return 0; +} + +/* + * The app timer in one shot mode obviously has to be reprogrammed + * in EXACTLY this sequence to work properly. Do NOT try to e.g. replace + * the interrupt disable + timer disable commands with a reset command, + * it will fail miserably. Apparently (and I found this the hard way) + * the timer is very sensitive to the instruction order, though you don't + * get that impression from the data sheet. + */ +static int u300_set_next_event(unsigned long cycles, + struct clock_event_device *evt) + +{ + /* Disable interrupts on GPT1 */ + writel(U300_TIMER_APP_GPT1IE_IRQ_DISABLE, + u300_timer_base + U300_TIMER_APP_GPT1IE); + /* Disable GP1 while we're reprogramming it. */ + writel(U300_TIMER_APP_DGPT1_TIMER_DISABLE, + u300_timer_base + U300_TIMER_APP_DGPT1); + /* Reset the General Purpose timer 1. */ + writel(U300_TIMER_APP_RGPT1_TIMER_RESET, + u300_timer_base + U300_TIMER_APP_RGPT1); + /* IRQ in n * cycles */ + writel(cycles, u300_timer_base + U300_TIMER_APP_GPT1TC); + /* + * We run one shot per tick here! (This is necessary to reconfigure, + * the timer will tilt if you don't!) + */ + writel(U300_TIMER_APP_SGPT1M_MODE_ONE_SHOT, + u300_timer_base + U300_TIMER_APP_SGPT1M); + /* Enable timer interrupts */ + writel(U300_TIMER_APP_GPT1IE_IRQ_ENABLE, + u300_timer_base + U300_TIMER_APP_GPT1IE); + /* Then enable the OS timer again */ + writel(U300_TIMER_APP_EGPT1_TIMER_ENABLE, + u300_timer_base + U300_TIMER_APP_EGPT1); + return 0; +} + +static struct u300_clockevent_data u300_clockevent_data = { + /* Use general purpose timer 1 as clock event */ + .cevd = { + .name = "GPT1", + /* Reasonably fast and accurate clock event */ + .rating = 300, + .features = CLOCK_EVT_FEAT_PERIODIC | + CLOCK_EVT_FEAT_ONESHOT, + .set_next_event = u300_set_next_event, + .set_state_shutdown = u300_shutdown, + .set_state_periodic = u300_set_periodic, + .set_state_oneshot = u300_set_oneshot, + }, +}; + +/* Clock event timer interrupt handler */ +static irqreturn_t u300_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evt = &u300_clockevent_data.cevd; + /* ACK/Clear timer IRQ for the APP GPT1 Timer */ + + writel(U300_TIMER_APP_GPT1IA_IRQ_ACK, + u300_timer_base + U300_TIMER_APP_GPT1IA); + evt->event_handler(evt); + return IRQ_HANDLED; +} + +/* + * Override the global weak sched_clock symbol with this + * local implementation which uses the clocksource to get some + * better resolution when scheduling the kernel. We accept that + * this wraps around for now, since it is just a relative time + * stamp. (Inspired by OMAP implementation.) + */ + +static u64 notrace u300_read_sched_clock(void) +{ + return readl(u300_timer_base + U300_TIMER_APP_GPT2CC); +} + +static unsigned long u300_read_current_timer(void) +{ + return readl(u300_timer_base + U300_TIMER_APP_GPT2CC); +} + +static struct delay_timer u300_delay_timer; + +/* + * This sets up the system timers, clock source and clock event. + */ +static int __init u300_timer_init_of(struct device_node *np) +{ + unsigned int irq; + struct clk *clk; + unsigned long rate; + int ret; + + u300_timer_base = of_iomap(np, 0); + if (!u300_timer_base) { + pr_err("could not ioremap system timer\n"); + return -ENXIO; + } + + /* Get the IRQ for the GP1 timer */ + irq = irq_of_parse_and_map(np, 2); + if (!irq) { + pr_err("no IRQ for system timer\n"); + return -EINVAL; + } + + pr_info("U300 GP1 timer @ base: %p, IRQ: %u\n", u300_timer_base, irq); + + /* Clock the interrupt controller */ + clk = of_clk_get(np, 0); + if (IS_ERR(clk)) + return PTR_ERR(clk); + + ret = clk_prepare_enable(clk); + if (ret) + return ret; + + rate = clk_get_rate(clk); + + u300_clockevent_data.ticks_per_jiffy = DIV_ROUND_CLOSEST(rate, HZ); + + sched_clock_register(u300_read_sched_clock, 32, rate); + + u300_delay_timer.read_current_timer = &u300_read_current_timer; + u300_delay_timer.freq = rate; + register_current_timer_delay(&u300_delay_timer); + + /* + * Disable the "OS" and "DD" timers - these are designed for Symbian! + * Example usage in cnh1601578 cpu subsystem pd_timer_app.c + */ + writel(U300_TIMER_APP_CRC_CLOCK_REQUEST_ENABLE, + u300_timer_base + U300_TIMER_APP_CRC); + writel(U300_TIMER_APP_ROST_TIMER_RESET, + u300_timer_base + U300_TIMER_APP_ROST); + writel(U300_TIMER_APP_DOST_TIMER_DISABLE, + u300_timer_base + U300_TIMER_APP_DOST); + writel(U300_TIMER_APP_RDDT_TIMER_RESET, + u300_timer_base + U300_TIMER_APP_RDDT); + writel(U300_TIMER_APP_DDDT_TIMER_DISABLE, + u300_timer_base + U300_TIMER_APP_DDDT); + + /* Reset the General Purpose timer 1. */ + writel(U300_TIMER_APP_RGPT1_TIMER_RESET, + u300_timer_base + U300_TIMER_APP_RGPT1); + + /* Set up the IRQ handler */ + ret = request_irq(irq, u300_timer_interrupt, + IRQF_TIMER | IRQF_IRQPOLL, "U300 Timer Tick", NULL); + if (ret) + return ret; + + /* Reset the General Purpose timer 2 */ + writel(U300_TIMER_APP_RGPT2_TIMER_RESET, + u300_timer_base + U300_TIMER_APP_RGPT2); + /* Set this timer to run around forever */ + writel(0xFFFFFFFFU, u300_timer_base + U300_TIMER_APP_GPT2TC); + /* Set continuous mode so it wraps around */ + writel(U300_TIMER_APP_SGPT2M_MODE_CONTINUOUS, + u300_timer_base + U300_TIMER_APP_SGPT2M); + /* Disable timer interrupts */ + writel(U300_TIMER_APP_GPT2IE_IRQ_DISABLE, + u300_timer_base + U300_TIMER_APP_GPT2IE); + /* Then enable the GP2 timer to use as a free running us counter */ + writel(U300_TIMER_APP_EGPT2_TIMER_ENABLE, + u300_timer_base + U300_TIMER_APP_EGPT2); + + /* Use general purpose timer 2 as clock source */ + ret = clocksource_mmio_init(u300_timer_base + U300_TIMER_APP_GPT2CC, + "GPT2", rate, 300, 32, clocksource_mmio_readl_up); + if (ret) { + pr_err("timer: failed to initialize U300 clock source\n"); + return ret; + } + + /* Configure and register the clockevent */ + clockevents_config_and_register(&u300_clockevent_data.cevd, rate, + 1, 0xffffffff); + + /* + * TODO: init and register the rest of the timers too, they can be + * used by hrtimers! + */ + return 0; +} + +TIMER_OF_DECLARE(u300_timer, "stericsson,u300-apptimer", + u300_timer_init_of); |