diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2014-10-08 17:37:16 -0400 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-10-08 17:37:16 -0400 |
commit | 8b45bc892e6842115fc87c2b2a3b86a20617606a (patch) | |
tree | 636c804eb29bb97070e7d2bc4d5ab9d1dad27cac /drivers/clocksource | |
parent | eb785bef684f2b7d03b530efc8e6f199e9777e2f (diff) | |
parent | fa637bf0595ee1796d728a0d33b6b7fff12e1f3d (diff) |
Merge tag 'drivers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
Pull ARM SoC driver updates from Arnd Bergmann:
"These are changes for drivers that are intimately tied to some SoC and
for some reason could not get merged through the respective subsystem
maintainer tree.
Most of the new code is for the Keystone Navigator driver, which is
new base support that is going to be needed for their hardware
accelerated network driver and other units.
Most of the commits are for moving old code around from at91 and omap
for things that are done in device drivers nowadays.
- at91: move reset, poweroff, memory and clocksource code into
drivers directories
- socfpga: add edac driver (through arm-soc, as requested by Boris)
- omap: move omap-intc code to drivers/irqchip
- sunxi: added an RTC driver for sun6i
- omap: mailbox driver related changes
- keystone: support for the "Navigator" component
- versatile: new reboot, led and soc drivers"
* tag 'drivers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (92 commits)
bus: arm-ccn: Fix spurious warning message
leds: add device tree bindings for register bit LEDs
soc: add driver for the ARM RealView
power: reset: driver for the Versatile syscon reboot
leds: add a driver for syscon-based LEDs
drivers/soc: ti: fix build break with modules
MAINTAINERS: Add Keystone Multicore Navigator drivers entry
soc: ti: add Keystone Navigator DMA support
Documentation: dt: soc: add Keystone Navigator DMA bindings
soc: ti: add Keystone Navigator QMSS driver
Documentation: dt: soc: add Keystone Navigator QMSS bindings
rtc: sunxi: Depend on platforms sun4i/sun7i that actually have the rtc
rtc: sun6i: Add sun6i RTC driver
irqchip: omap-intc: remove unnecessary comments
irqchip: omap-intc: correct maximum number or MIR registers
irqchip: omap-intc: enable TURBO idle mode
irqchip: omap-intc: enable IP protection
irqchip: omap-intc: remove unnecesary of_address_to_resource() call
irqchip: omap-intc: comment style cleanup
irqchip: omap-intc: minor improvement to omap_irq_pending()
...
Diffstat (limited to 'drivers/clocksource')
-rw-r--r-- | drivers/clocksource/Kconfig | 4 | ||||
-rw-r--r-- | drivers/clocksource/Makefile | 1 | ||||
-rw-r--r-- | drivers/clocksource/timer-atmel-pit.c | 296 |
3 files changed, 301 insertions, 0 deletions
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index cfd6519df66..82a2ebe41e2 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -120,6 +120,10 @@ config CLKSRC_ARM_GLOBAL_TIMER_SCHED_CLOCK help Use ARM global timer clock source as sched_clock +config ATMEL_PIT + select CLKSRC_OF if OF + def_bool SOC_AT91SAM9 || SOC_SAMA5 + config CLKSRC_METAG_GENERIC def_bool y if METAG help diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index 7fd9fd1dff4..e566f6c7ded 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -1,4 +1,5 @@ obj-$(CONFIG_CLKSRC_OF) += clksrc-of.o +obj-$(CONFIG_ATMEL_PIT) += timer-atmel-pit.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-pit.c b/drivers/clocksource/timer-atmel-pit.c new file mode 100644 index 00000000000..d5289098b3d --- /dev/null +++ b/drivers/clocksource/timer-atmel-pit.c @@ -0,0 +1,296 @@ +/* + * at91sam926x_time.c - Periodic Interval Timer (PIT) for at91sam926x + * + * Copyright (C) 2005-2006 M. Amine SAYA, ATMEL Rousset, France + * Revision 2005 M. Nicolas Diremdjian, ATMEL Rousset, France + * Converted to ClockSource/ClockEvents by David Brownell. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#define pr_fmt(fmt) "AT91: PIT: " fmt + +#include <linux/clk.h> +#include <linux/clockchips.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/kernel.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/slab.h> + +#define AT91_PIT_MR 0x00 /* Mode Register */ +#define AT91_PIT_PITIEN BIT(25) /* Timer Interrupt Enable */ +#define AT91_PIT_PITEN BIT(24) /* Timer Enabled */ +#define AT91_PIT_PIV GENMASK(19, 0) /* Periodic Interval Value */ + +#define AT91_PIT_SR 0x04 /* Status Register */ +#define AT91_PIT_PITS BIT(0) /* Timer Status */ + +#define AT91_PIT_PIVR 0x08 /* Periodic Interval Value Register */ +#define AT91_PIT_PIIR 0x0c /* Periodic Interval Image Register */ +#define AT91_PIT_PICNT GENMASK(31, 20) /* Interval Counter */ +#define AT91_PIT_CPIV GENMASK(19, 0) /* Inverval Value */ + +#define PIT_CPIV(x) ((x) & AT91_PIT_CPIV) +#define PIT_PICNT(x) (((x) & AT91_PIT_PICNT) >> 20) + +struct pit_data { + struct clock_event_device clkevt; + struct clocksource clksrc; + + void __iomem *base; + u32 cycle; + u32 cnt; + unsigned int irq; + struct clk *mck; +}; + +static inline struct pit_data *clksrc_to_pit_data(struct clocksource *clksrc) +{ + return container_of(clksrc, struct pit_data, clksrc); +} + +static inline struct pit_data *clkevt_to_pit_data(struct clock_event_device *clkevt) +{ + return container_of(clkevt, struct pit_data, clkevt); +} + +static inline unsigned int pit_read(void __iomem *base, unsigned int reg_offset) +{ + return __raw_readl(base + reg_offset); +} + +static inline void pit_write(void __iomem *base, unsigned int reg_offset, unsigned long value) +{ + __raw_writel(value, base + reg_offset); +} + +/* + * Clocksource: just a monotonic counter of MCK/16 cycles. + * We don't care whether or not PIT irqs are enabled. + */ +static cycle_t read_pit_clk(struct clocksource *cs) +{ + struct pit_data *data = clksrc_to_pit_data(cs); + unsigned long flags; + u32 elapsed; + u32 t; + + raw_local_irq_save(flags); + elapsed = data->cnt; + t = pit_read(data->base, AT91_PIT_PIIR); + raw_local_irq_restore(flags); + + elapsed += PIT_PICNT(t) * data->cycle; + elapsed += PIT_CPIV(t); + return elapsed; +} + +/* + * Clockevent device: interrupts every 1/HZ (== pit_cycles * MCK/16) + */ +static void +pit_clkevt_mode(enum clock_event_mode mode, struct clock_event_device *dev) +{ + struct pit_data *data = clkevt_to_pit_data(dev); + + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + /* update clocksource counter */ + data->cnt += data->cycle * PIT_PICNT(pit_read(data->base, AT91_PIT_PIVR)); + pit_write(data->base, AT91_PIT_MR, + (data->cycle - 1) | AT91_PIT_PITEN | AT91_PIT_PITIEN); + break; + case CLOCK_EVT_MODE_ONESHOT: + BUG(); + /* FALLTHROUGH */ + case CLOCK_EVT_MODE_SHUTDOWN: + case CLOCK_EVT_MODE_UNUSED: + /* disable irq, leaving the clocksource active */ + pit_write(data->base, AT91_PIT_MR, + (data->cycle - 1) | AT91_PIT_PITEN); + break; + case CLOCK_EVT_MODE_RESUME: + break; + } +} + +static void at91sam926x_pit_suspend(struct clock_event_device *cedev) +{ + struct pit_data *data = clkevt_to_pit_data(cedev); + + /* Disable timer */ + pit_write(data->base, AT91_PIT_MR, 0); +} + +static void at91sam926x_pit_reset(struct pit_data *data) +{ + /* Disable timer and irqs */ + pit_write(data->base, AT91_PIT_MR, 0); + + /* Clear any pending interrupts, wait for PIT to stop counting */ + while (PIT_CPIV(pit_read(data->base, AT91_PIT_PIVR)) != 0) + cpu_relax(); + + /* Start PIT but don't enable IRQ */ + pit_write(data->base, AT91_PIT_MR, + (data->cycle - 1) | AT91_PIT_PITEN); +} + +static void at91sam926x_pit_resume(struct clock_event_device *cedev) +{ + struct pit_data *data = clkevt_to_pit_data(cedev); + + at91sam926x_pit_reset(data); +} + +/* + * IRQ handler for the timer. + */ +static irqreturn_t at91sam926x_pit_interrupt(int irq, void *dev_id) +{ + struct pit_data *data = dev_id; + + /* + * 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()); + + /* The PIT interrupt may be disabled, and is shared */ + if ((data->clkevt.mode == CLOCK_EVT_MODE_PERIODIC) && + (pit_read(data->base, AT91_PIT_SR) & AT91_PIT_PITS)) { + unsigned nr_ticks; + + /* Get number of ticks performed before irq, and ack it */ + nr_ticks = PIT_PICNT(pit_read(data->base, AT91_PIT_PIVR)); + do { + data->cnt += data->cycle; + data->clkevt.event_handler(&data->clkevt); + nr_ticks--; + } while (nr_ticks); + + return IRQ_HANDLED; + } + + return IRQ_NONE; +} + +/* + * Set up both clocksource and clockevent support. + */ +static void __init at91sam926x_pit_common_init(struct pit_data *data) +{ + unsigned long pit_rate; + unsigned bits; + int ret; + + /* + * Use our actual MCK to figure out how many MCK/16 ticks per + * 1/HZ period (instead of a compile-time constant LATCH). + */ + pit_rate = clk_get_rate(data->mck) / 16; + data->cycle = DIV_ROUND_CLOSEST(pit_rate, HZ); + WARN_ON(((data->cycle - 1) & ~AT91_PIT_PIV) != 0); + + /* Initialize and enable the timer */ + at91sam926x_pit_reset(data); + + /* + * Register clocksource. The high order bits of PIV are unused, + * so this isn't a 32-bit counter unless we get clockevent irqs. + */ + bits = 12 /* PICNT */ + ilog2(data->cycle) /* PIV */; + data->clksrc.mask = CLOCKSOURCE_MASK(bits); + data->clksrc.name = "pit"; + data->clksrc.rating = 175; + data->clksrc.read = read_pit_clk, + data->clksrc.flags = CLOCK_SOURCE_IS_CONTINUOUS, + clocksource_register_hz(&data->clksrc, pit_rate); + + /* Set up irq handler */ + ret = request_irq(data->irq, at91sam926x_pit_interrupt, + IRQF_SHARED | IRQF_TIMER | IRQF_IRQPOLL, + "at91_tick", data); + if (ret) + panic(pr_fmt("Unable to setup IRQ\n")); + + /* Set up and register clockevents */ + data->clkevt.name = "pit"; + data->clkevt.features = CLOCK_EVT_FEAT_PERIODIC; + data->clkevt.shift = 32; + data->clkevt.mult = div_sc(pit_rate, NSEC_PER_SEC, data->clkevt.shift); + data->clkevt.rating = 100; + data->clkevt.cpumask = cpumask_of(0); + + data->clkevt.set_mode = pit_clkevt_mode; + data->clkevt.resume = at91sam926x_pit_resume; + data->clkevt.suspend = at91sam926x_pit_suspend; + clockevents_register_device(&data->clkevt); +} + +static void __init at91sam926x_pit_dt_init(struct device_node *node) +{ + struct pit_data *data; + + data = kzalloc(sizeof(*data), GFP_KERNEL); + if (!data) + panic(pr_fmt("Unable to allocate memory\n")); + + data->base = of_iomap(node, 0); + if (!data->base) + panic(pr_fmt("Could not map PIT address\n")); + + data->mck = of_clk_get(node, 0); + if (IS_ERR(data->mck)) + /* Fallback on clkdev for !CCF-based boards */ + data->mck = clk_get(NULL, "mck"); + + if (IS_ERR(data->mck)) + panic(pr_fmt("Unable to get mck clk\n")); + + /* Get the interrupts property */ + data->irq = irq_of_parse_and_map(node, 0); + if (!data->irq) + panic(pr_fmt("Unable to get IRQ from DT\n")); + + at91sam926x_pit_common_init(data); +} +CLOCKSOURCE_OF_DECLARE(at91sam926x_pit, "atmel,at91sam9260-pit", + at91sam926x_pit_dt_init); + +static void __iomem *pit_base_addr; + +void __init at91sam926x_pit_init(int irq) +{ + struct pit_data *data; + + data = kzalloc(sizeof(*data), GFP_KERNEL); + if (!data) + panic(pr_fmt("Unable to allocate memory\n")); + + data->base = pit_base_addr; + + data->mck = clk_get(NULL, "mck"); + if (IS_ERR(data->mck)) + panic(pr_fmt("Unable to get mck clk\n")); + + data->irq = irq; + + at91sam926x_pit_common_init(data); +} + +void __init at91sam926x_ioremap_pit(u32 addr) +{ + if (of_have_populated_dt()) + return; + + pit_base_addr = ioremap(addr, 16); + + if (!pit_base_addr) + panic(pr_fmt("Impossible to ioremap PIT\n")); +} |