From b53cdd03222391f76e82cd0c7d040816c919ab75 Mon Sep 17 00:00:00 2001 From: Alexandre Belloni Date: Thu, 12 Mar 2015 13:07:31 +0100 Subject: ARM: at91: time: move the system timer driver to drivers/clocksource Import at91rm9200_time.c from mach-at91 as timer-atmel-st.c. Further cleanup is required to get rid of the mach-at91 headers. Signed-off-by: Alexandre Belloni Acked-by: Boris Brezillon Acked-by: Daniel Lezcano Signed-off-by: Nicolas Ferre diff --git a/arch/arm/mach-at91/Kconfig b/arch/arm/mach-at91/Kconfig index 4da6bae..24b59c7 100644 --- a/arch/arm/mach-at91/Kconfig +++ b/arch/arm/mach-at91/Kconfig @@ -77,6 +77,7 @@ if SOC_SAM_V4_V5 config SOC_AT91RM9200 bool "AT91RM9200" select ATMEL_AIC_IRQ + select ATMEL_ST select COMMON_CLK_AT91 select CPU_ARM920T select GENERIC_CLOCKEVENTS diff --git a/arch/arm/mach-at91/Makefile b/arch/arm/mach-at91/Makefile index ea54c98..38aaef7 100644 --- a/arch/arm/mach-at91/Makefile +++ b/arch/arm/mach-at91/Makefile @@ -7,7 +7,7 @@ obj-y := soc.o obj-$(CONFIG_SOC_AT91SAM9) += sam9_smc.o # CPU-specific support -obj-$(CONFIG_SOC_AT91RM9200) += at91rm9200.o at91rm9200_time.o +obj-$(CONFIG_SOC_AT91RM9200) += at91rm9200.o obj-$(CONFIG_SOC_AT91SAM9) += at91sam9.o obj-$(CONFIG_SOC_SAMA5) += sama5.o diff --git a/arch/arm/mach-at91/at91rm9200_time.c b/arch/arm/mach-at91/at91rm9200_time.c deleted file mode 100644 index 7d062ab..0000000 --- a/arch/arm/mach-at91/at91rm9200_time.c +++ /dev/null @@ -1,253 +0,0 @@ -/* - * linux/arch/arm/mach-at91/at91rm9200_time.c - * - * Copyright (C) 2003 SAN People - * Copyright (C) 2003 ATMEL - * - * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA - */ - -#include -#include -#include -#include -#include -#include -#include -#include - -#include - -#include -#include - -static unsigned long last_crtr; -static u32 irqmask; -static struct clock_event_device clkevt; - -#define RM9200_TIMER_LATCH ((AT91_SLOW_CLOCK + HZ/2) / HZ) - -/* - * The ST_CRTR is updated asynchronously to the master clock ... but - * the updates as seen by the CPU don't seem to be strictly monotonic. - * Waiting until we read the same value twice avoids glitching. - */ -static inline unsigned long read_CRTR(void) -{ - unsigned long x1, x2; - - x1 = at91_st_read(AT91_ST_CRTR); - do { - x2 = at91_st_read(AT91_ST_CRTR); - if (x1 == x2) - break; - x1 = x2; - } while (1); - return x1; -} - -/* - * IRQ handler for the timer. - */ -static irqreturn_t at91rm9200_timer_interrupt(int irq, void *dev_id) -{ - u32 sr = at91_st_read(AT91_ST_SR) & irqmask; - - /* - * irqs should be disabled here, but as the irq is shared they are only - * guaranteed to be off if the timer irq is registered first. - */ - WARN_ON_ONCE(!irqs_disabled()); - - /* simulate "oneshot" timer with alarm */ - if (sr & AT91_ST_ALMS) { - clkevt.event_handler(&clkevt); - return IRQ_HANDLED; - } - - /* periodic mode should handle delayed ticks */ - if (sr & AT91_ST_PITS) { - u32 crtr = read_CRTR(); - - while (((crtr - last_crtr) & AT91_ST_CRTV) >= RM9200_TIMER_LATCH) { - last_crtr += RM9200_TIMER_LATCH; - clkevt.event_handler(&clkevt); - } - return IRQ_HANDLED; - } - - /* this irq is shared ... */ - return IRQ_NONE; -} - -static struct irqaction at91rm9200_timer_irq = { - .name = "at91_tick", - .flags = IRQF_SHARED | IRQF_TIMER | IRQF_IRQPOLL, - .handler = at91rm9200_timer_interrupt, - .irq = NR_IRQS_LEGACY + AT91_ID_SYS, -}; - -static cycle_t read_clk32k(struct clocksource *cs) -{ - return read_CRTR(); -} - -static struct clocksource clk32k = { - .name = "32k_counter", - .rating = 150, - .read = read_clk32k, - .mask = CLOCKSOURCE_MASK(20), - .flags = CLOCK_SOURCE_IS_CONTINUOUS, -}; - -static void -clkevt32k_mode(enum clock_event_mode mode, struct clock_event_device *dev) -{ - /* Disable and flush pending timer interrupts */ - at91_st_write(AT91_ST_IDR, AT91_ST_PITS | AT91_ST_ALMS); - at91_st_read(AT91_ST_SR); - - last_crtr = read_CRTR(); - switch (mode) { - case CLOCK_EVT_MODE_PERIODIC: - /* PIT for periodic irqs; fixed rate of 1/HZ */ - irqmask = AT91_ST_PITS; - at91_st_write(AT91_ST_PIMR, RM9200_TIMER_LATCH); - break; - case CLOCK_EVT_MODE_ONESHOT: - /* ALM for oneshot irqs, set by next_event() - * before 32 seconds have passed - */ - irqmask = AT91_ST_ALMS; - at91_st_write(AT91_ST_RTAR, last_crtr); - break; - case CLOCK_EVT_MODE_SHUTDOWN: - case CLOCK_EVT_MODE_UNUSED: - case CLOCK_EVT_MODE_RESUME: - irqmask = 0; - break; - } - at91_st_write(AT91_ST_IER, irqmask); -} - -static int -clkevt32k_next_event(unsigned long delta, struct clock_event_device *dev) -{ - u32 alm; - int status = 0; - - BUG_ON(delta < 2); - - /* The alarm IRQ uses absolute time (now+delta), not the relative - * time (delta) in our calling convention. Like all clockevents - * using such "match" hardware, we have a race to defend against. - * - * Our defense here is to have set up the clockevent device so the - * delta is at least two. That way we never end up writing RTAR - * with the value then held in CRTR ... which would mean the match - * wouldn't trigger until 32 seconds later, after CRTR wraps. - */ - alm = read_CRTR(); - - /* Cancel any pending alarm; flush any pending IRQ */ - at91_st_write(AT91_ST_RTAR, alm); - at91_st_read(AT91_ST_SR); - - /* Schedule alarm by writing RTAR. */ - alm += delta; - at91_st_write(AT91_ST_RTAR, alm); - - return status; -} - -static struct clock_event_device clkevt = { - .name = "at91_tick", - .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, - .rating = 150, - .set_next_event = clkevt32k_next_event, - .set_mode = clkevt32k_mode, -}; - -void __iomem *at91_st_base; -EXPORT_SYMBOL_GPL(at91_st_base); - -static const struct of_device_id at91rm9200_st_timer_ids[] = { - { .compatible = "atmel,at91rm9200-st" }, - { /* sentinel */ } -}; - -static int __init of_at91rm9200_st_init(void) -{ - struct device_node *np; - int ret; - - np = of_find_matching_node(NULL, at91rm9200_st_timer_ids); - if (!np) - goto err; - - at91_st_base = of_iomap(np, 0); - if (!at91_st_base) - goto node_err; - - /* Get the interrupts property */ - ret = irq_of_parse_and_map(np, 0); - if (!ret) - goto ioremap_err; - at91rm9200_timer_irq.irq = ret; - - of_node_put(np); - - return 0; - -ioremap_err: - iounmap(at91_st_base); -node_err: - of_node_put(np); -err: - return -EINVAL; -} - -/* - * ST (system timer) module supports both clockevents and clocksource. - */ -static void __init atmel_st_timer_init(struct device_node *node) -{ - /* For device tree enabled device: initialize here */ - of_at91rm9200_st_init(); - - /* Disable all timer interrupts, and clear any pending ones */ - at91_st_write(AT91_ST_IDR, - AT91_ST_PITS | AT91_ST_WDOVF | AT91_ST_RTTINC | AT91_ST_ALMS); - at91_st_read(AT91_ST_SR); - - /* Make IRQs happen for the system timer */ - setup_irq(at91rm9200_timer_irq.irq, &at91rm9200_timer_irq); - - /* The 32KiHz "Slow Clock" (tick every 30517.58 nanoseconds) is used - * directly for the clocksource and all clockevents, after adjusting - * its prescaler from the 1 Hz default. - */ - at91_st_write(AT91_ST_RTMR, 1); - - /* Setup timer clockevent, with minimum of two ticks (important!!) */ - clkevt.cpumask = cpumask_of(0); - clockevents_config_and_register(&clkevt, AT91_SLOW_CLOCK, - 2, AT91_ST_ALMV); - - /* register clocksource */ - clocksource_register_hz(&clk32k, AT91_SLOW_CLOCK); -} -CLOCKSOURCE_OF_DECLARE(atmel_st_timer, "atmel,at91rm9200-st", - atmel_st_timer_init); diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index 68161f7..1680358 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -143,6 +143,10 @@ config ATMEL_PIT select CLKSRC_OF if OF def_bool SOC_AT91SAM9 || SOC_SAMA5 +config ATMEL_ST + bool + select CLKSRC_OF + config CLKSRC_METAG_GENERIC def_bool y if METAG help diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index 752d5c7..5b85f6a 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -1,5 +1,6 @@ obj-$(CONFIG_CLKSRC_OF) += clksrc-of.o obj-$(CONFIG_ATMEL_PIT) += timer-atmel-pit.o +obj-$(CONFIG_ATMEL_ST) += timer-atmel-st.o obj-$(CONFIG_ATMEL_TCB_CLKSRC) += tcb_clksrc.o obj-$(CONFIG_X86_PM_TIMER) += acpi_pm.o obj-$(CONFIG_SCx200HR_TIMER) += scx200_hrt.o diff --git a/drivers/clocksource/timer-atmel-st.c b/drivers/clocksource/timer-atmel-st.c new file mode 100644 index 0000000..7d062ab --- /dev/null +++ b/drivers/clocksource/timer-atmel-st.c @@ -0,0 +1,253 @@ +/* + * linux/arch/arm/mach-at91/at91rm9200_time.c + * + * Copyright (C) 2003 SAN People + * Copyright (C) 2003 ATMEL + * + * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#include +#include + +static unsigned long last_crtr; +static u32 irqmask; +static struct clock_event_device clkevt; + +#define RM9200_TIMER_LATCH ((AT91_SLOW_CLOCK + HZ/2) / HZ) + +/* + * The ST_CRTR is updated asynchronously to the master clock ... but + * the updates as seen by the CPU don't seem to be strictly monotonic. + * Waiting until we read the same value twice avoids glitching. + */ +static inline unsigned long read_CRTR(void) +{ + unsigned long x1, x2; + + x1 = at91_st_read(AT91_ST_CRTR); + do { + x2 = at91_st_read(AT91_ST_CRTR); + if (x1 == x2) + break; + x1 = x2; + } while (1); + return x1; +} + +/* + * IRQ handler for the timer. + */ +static irqreturn_t at91rm9200_timer_interrupt(int irq, void *dev_id) +{ + u32 sr = at91_st_read(AT91_ST_SR) & irqmask; + + /* + * irqs should be disabled here, but as the irq is shared they are only + * guaranteed to be off if the timer irq is registered first. + */ + WARN_ON_ONCE(!irqs_disabled()); + + /* simulate "oneshot" timer with alarm */ + if (sr & AT91_ST_ALMS) { + clkevt.event_handler(&clkevt); + return IRQ_HANDLED; + } + + /* periodic mode should handle delayed ticks */ + if (sr & AT91_ST_PITS) { + u32 crtr = read_CRTR(); + + while (((crtr - last_crtr) & AT91_ST_CRTV) >= RM9200_TIMER_LATCH) { + last_crtr += RM9200_TIMER_LATCH; + clkevt.event_handler(&clkevt); + } + return IRQ_HANDLED; + } + + /* this irq is shared ... */ + return IRQ_NONE; +} + +static struct irqaction at91rm9200_timer_irq = { + .name = "at91_tick", + .flags = IRQF_SHARED | IRQF_TIMER | IRQF_IRQPOLL, + .handler = at91rm9200_timer_interrupt, + .irq = NR_IRQS_LEGACY + AT91_ID_SYS, +}; + +static cycle_t read_clk32k(struct clocksource *cs) +{ + return read_CRTR(); +} + +static struct clocksource clk32k = { + .name = "32k_counter", + .rating = 150, + .read = read_clk32k, + .mask = CLOCKSOURCE_MASK(20), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +static void +clkevt32k_mode(enum clock_event_mode mode, struct clock_event_device *dev) +{ + /* Disable and flush pending timer interrupts */ + at91_st_write(AT91_ST_IDR, AT91_ST_PITS | AT91_ST_ALMS); + at91_st_read(AT91_ST_SR); + + last_crtr = read_CRTR(); + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + /* PIT for periodic irqs; fixed rate of 1/HZ */ + irqmask = AT91_ST_PITS; + at91_st_write(AT91_ST_PIMR, RM9200_TIMER_LATCH); + break; + case CLOCK_EVT_MODE_ONESHOT: + /* ALM for oneshot irqs, set by next_event() + * before 32 seconds have passed + */ + irqmask = AT91_ST_ALMS; + at91_st_write(AT91_ST_RTAR, last_crtr); + break; + case CLOCK_EVT_MODE_SHUTDOWN: + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_RESUME: + irqmask = 0; + break; + } + at91_st_write(AT91_ST_IER, irqmask); +} + +static int +clkevt32k_next_event(unsigned long delta, struct clock_event_device *dev) +{ + u32 alm; + int status = 0; + + BUG_ON(delta < 2); + + /* The alarm IRQ uses absolute time (now+delta), not the relative + * time (delta) in our calling convention. Like all clockevents + * using such "match" hardware, we have a race to defend against. + * + * Our defense here is to have set up the clockevent device so the + * delta is at least two. That way we never end up writing RTAR + * with the value then held in CRTR ... which would mean the match + * wouldn't trigger until 32 seconds later, after CRTR wraps. + */ + alm = read_CRTR(); + + /* Cancel any pending alarm; flush any pending IRQ */ + at91_st_write(AT91_ST_RTAR, alm); + at91_st_read(AT91_ST_SR); + + /* Schedule alarm by writing RTAR. */ + alm += delta; + at91_st_write(AT91_ST_RTAR, alm); + + return status; +} + +static struct clock_event_device clkevt = { + .name = "at91_tick", + .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, + .rating = 150, + .set_next_event = clkevt32k_next_event, + .set_mode = clkevt32k_mode, +}; + +void __iomem *at91_st_base; +EXPORT_SYMBOL_GPL(at91_st_base); + +static const struct of_device_id at91rm9200_st_timer_ids[] = { + { .compatible = "atmel,at91rm9200-st" }, + { /* sentinel */ } +}; + +static int __init of_at91rm9200_st_init(void) +{ + struct device_node *np; + int ret; + + np = of_find_matching_node(NULL, at91rm9200_st_timer_ids); + if (!np) + goto err; + + at91_st_base = of_iomap(np, 0); + if (!at91_st_base) + goto node_err; + + /* Get the interrupts property */ + ret = irq_of_parse_and_map(np, 0); + if (!ret) + goto ioremap_err; + at91rm9200_timer_irq.irq = ret; + + of_node_put(np); + + return 0; + +ioremap_err: + iounmap(at91_st_base); +node_err: + of_node_put(np); +err: + return -EINVAL; +} + +/* + * ST (system timer) module supports both clockevents and clocksource. + */ +static void __init atmel_st_timer_init(struct device_node *node) +{ + /* For device tree enabled device: initialize here */ + of_at91rm9200_st_init(); + + /* Disable all timer interrupts, and clear any pending ones */ + at91_st_write(AT91_ST_IDR, + AT91_ST_PITS | AT91_ST_WDOVF | AT91_ST_RTTINC | AT91_ST_ALMS); + at91_st_read(AT91_ST_SR); + + /* Make IRQs happen for the system timer */ + setup_irq(at91rm9200_timer_irq.irq, &at91rm9200_timer_irq); + + /* The 32KiHz "Slow Clock" (tick every 30517.58 nanoseconds) is used + * directly for the clocksource and all clockevents, after adjusting + * its prescaler from the 1 Hz default. + */ + at91_st_write(AT91_ST_RTMR, 1); + + /* Setup timer clockevent, with minimum of two ticks (important!!) */ + clkevt.cpumask = cpumask_of(0); + clockevents_config_and_register(&clkevt, AT91_SLOW_CLOCK, + 2, AT91_ST_ALMV); + + /* register clocksource */ + clocksource_register_hz(&clk32k, AT91_SLOW_CLOCK); +} +CLOCKSOURCE_OF_DECLARE(atmel_st_timer, "atmel,at91rm9200-st", + atmel_st_timer_init); -- cgit v0.10.2