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[176.162.151.233]) by smtp.gmail.com with ESMTPSA id 135-v6sm2032331wmx.21.2018.06.07.07.06.07 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 07 Jun 2018 07:06:08 -0700 (PDT) From: =?UTF-8?q?Cl=C3=A9ment=20P=C3=A9ron?= To: Colin Didier , linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Daniel Lezcano , Thomas Gleixner , Fabio Estevam , Vladimir Zapolskiy , Sascha Hauer , Rob Herring , NXP Linux Team , Pengutronix Kernel Team , =?UTF-8?q?Cl=C3=A9ment=20Peron?= Subject: [PATCH v6 4/5] clocksource: add driver for i.MX EPIT timer Date: Thu, 7 Jun 2018 16:05:43 +0200 Message-Id: <20180607140544.22268-5-peron.clem@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180607140544.22268-1-peron.clem@gmail.com> References: <20180607140544.22268-1-peron.clem@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Colin Didier Add driver for NXP's EPIT timer used in i.MX SoC. Signed-off-by: Colin Didier Signed-off-by: Clément Peron --- drivers/clocksource/Kconfig | 11 ++ drivers/clocksource/Makefile | 1 + drivers/clocksource/timer-imx-epit.c | 265 +++++++++++++++++++++++++++ 3 files changed, 277 insertions(+) create mode 100644 drivers/clocksource/timer-imx-epit.c diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index 8e8a09755d10..790478afd02c 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -576,6 +576,17 @@ config H8300_TPU This enables the clocksource for the H8300 platform with the H8S2678 cpu. +config CLKSRC_IMX_EPIT + bool "Clocksource using i.MX EPIT" + depends on CLKDEV_LOOKUP && (ARCH_MXC || COMPILE_TEST) + select CLKSRC_MMIO + help + This enables EPIT support available on some i.MX platforms. + Normally you don't have a reason to do so as the EPIT has + the same features and uses the same clocks as the GPT. + Anyway, on some systems the GPT may be in use for other + purposes. + config CLKSRC_IMX_GPT bool "Clocksource using i.MX GPT" if COMPILE_TEST depends on ARM && CLKDEV_LOOKUP diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index 00caf37e52f9..d9426f69ec69 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -69,6 +69,7 @@ obj-$(CONFIG_INTEGRATOR_AP_TIMER) += timer-integrator-ap.o obj-$(CONFIG_CLKSRC_VERSATILE) += versatile.o obj-$(CONFIG_CLKSRC_MIPS_GIC) += mips-gic-timer.o obj-$(CONFIG_CLKSRC_TANGO_XTAL) += tango_xtal.o +obj-$(CONFIG_CLKSRC_IMX_EPIT) += timer-imx-epit.o obj-$(CONFIG_CLKSRC_IMX_GPT) += timer-imx-gpt.o obj-$(CONFIG_CLKSRC_IMX_TPM) += timer-imx-tpm.o obj-$(CONFIG_ASM9260_TIMER) += asm9260_timer.o diff --git a/drivers/clocksource/timer-imx-epit.c b/drivers/clocksource/timer-imx-epit.c new file mode 100644 index 000000000000..15f70e210fad --- /dev/null +++ b/drivers/clocksource/timer-imx-epit.c @@ -0,0 +1,265 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * i.MX EPIT Timer + * + * Copyright (C) 2010 Sascha Hauer + * Copyright (C) 2018 Colin Didier + * Copyright (C) 2018 Clément Péron + */ + +#include +#include +#include +#include +#include +#include +#include + +#define EPITCR 0x00 +#define EPITSR 0x04 +#define EPITLR 0x08 +#define EPITCMPR 0x0c +#define EPITCNR 0x10 + +#define EPITCR_EN BIT(0) +#define EPITCR_ENMOD BIT(1) +#define EPITCR_OCIEN BIT(2) +#define EPITCR_RLD BIT(3) +#define EPITCR_PRESC(x) (((x) & 0xfff) << 4) +#define EPITCR_SWR BIT(16) +#define EPITCR_IOVW BIT(17) +#define EPITCR_DBGEN BIT(18) +#define EPITCR_WAITEN BIT(19) +#define EPITCR_RES BIT(20) +#define EPITCR_STOPEN BIT(21) +#define EPITCR_OM_DISCON (0 << 22) +#define EPITCR_OM_TOGGLE (1 << 22) +#define EPITCR_OM_CLEAR (2 << 22) +#define EPITCR_OM_SET (3 << 22) +#define EPITCR_CLKSRC_OFF (0 << 24) +#define EPITCR_CLKSRC_PERIPHERAL (1 << 24) +#define EPITCR_CLKSRC_REF_HIGH (2 << 24) +#define EPITCR_CLKSRC_REF_LOW (3 << 24) + +#define EPITSR_OCIF BIT(0) + +struct epit_timer { + void __iomem *base; + int irq; + struct clk *clk; + struct clock_event_device ced; + struct irqaction act; +}; + +static void __iomem *sched_clock_reg; + +static inline struct epit_timer *to_epit_timer(struct clock_event_device *ced) +{ + return container_of(ced, struct epit_timer, ced); +} + +static inline void epit_irq_disable(struct epit_timer *epittm) +{ + u32 val; + + val = readl_relaxed(epittm->base + EPITCR); + writel_relaxed(val & ~EPITCR_OCIEN, epittm->base + EPITCR); +} + +static inline void epit_irq_enable(struct epit_timer *epittm) +{ + u32 val; + + val = readl_relaxed(epittm->base + EPITCR); + writel_relaxed(val | EPITCR_OCIEN, epittm->base + EPITCR); +} + +static void epit_irq_acknowledge(struct epit_timer *epittm) +{ + writel_relaxed(EPITSR_OCIF, epittm->base + EPITSR); +} + +static u64 notrace epit_read_sched_clock(void) +{ + return ~readl_relaxed(sched_clock_reg); +} + +static int epit_set_next_event(unsigned long cycles, + struct clock_event_device *ced) +{ + struct epit_timer *epittm = to_epit_timer(ced); + unsigned long tcmp; + + tcmp = readl_relaxed(epittm->base + EPITCNR) - cycles; + writel_relaxed(tcmp, epittm->base + EPITCMPR); + + return 0; +} + +/* Left event sources disabled, no more interrupts appear */ +static int epit_shutdown(struct clock_event_device *ced) +{ + struct epit_timer *epittm = to_epit_timer(ced); + unsigned long flags; + + /* + * The timer interrupt generation is disabled at least + * for enough time to call epit_set_next_event() + */ + local_irq_save(flags); + + /* Disable interrupt in EPIT module */ + epit_irq_disable(epittm); + + /* Clear pending interrupt */ + epit_irq_acknowledge(epittm); + + local_irq_restore(flags); + + return 0; +} + +static int epit_set_oneshot(struct clock_event_device *ced) +{ + struct epit_timer *epittm = to_epit_timer(ced); + unsigned long flags; + + /* + * The timer interrupt generation is disabled at least + * for enough time to call epit_set_next_event() + */ + local_irq_save(flags); + + /* Disable interrupt in EPIT module */ + epit_irq_disable(epittm); + + /* Clear pending interrupt, only while switching mode */ + if (!clockevent_state_oneshot(ced)) + epit_irq_acknowledge(epittm); + + /* + * Do not put overhead of interrupt enable/disable into + * epit_set_next_event(), the core has about 4 minutes + * to call epit_set_next_event() or shutdown clock after + * mode switching + */ + epit_irq_enable(epittm); + local_irq_restore(flags); + + return 0; +} + +static irqreturn_t epit_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *ced = dev_id; + struct epit_timer *epittm = to_epit_timer(ced); + + epit_irq_acknowledge(epittm); + + ced->event_handler(ced); + + return IRQ_HANDLED; +} + +static int __init epit_clocksource_init(struct epit_timer *epittm) +{ + unsigned int c = clk_get_rate(epittm->clk); + + sched_clock_reg = epittm->base + EPITCNR; + sched_clock_register(epit_read_sched_clock, 32, c); + + return clocksource_mmio_init(epittm->base + EPITCNR, "epit", c, 200, 32, + clocksource_mmio_readl_down); +} + +static int __init epit_clockevent_init(struct epit_timer *epittm) +{ + struct clock_event_device *ced = &epittm->ced; + struct irqaction *act = &epittm->act; + + ced->name = "epit"; + ced->features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_DYNIRQ; + ced->set_state_shutdown = epit_shutdown; + ced->tick_resume = epit_shutdown; + ced->set_state_oneshot = epit_set_oneshot; + ced->set_next_event = epit_set_next_event; + ced->rating = 200; + ced->cpumask = cpumask_of(0); + ced->irq = epittm->irq; + clockevents_config_and_register(ced, clk_get_rate(epittm->clk), + 0xff, 0xfffffffe); + + act->name = "i.MX EPIT Timer Tick", + act->flags = IRQF_TIMER | IRQF_IRQPOLL; + act->handler = epit_timer_interrupt; + act->dev_id = ced; + + /* Make irqs happen */ + return setup_irq(epittm->irq, act); +} + +static int __init epit_timer_init(struct device_node *np) +{ + struct epit_timer *epittm; + int ret; + + epittm = kzalloc(sizeof(*epittm), GFP_KERNEL); + if (!epittm) + return -ENOMEM; + + epittm->base = of_iomap(np, 0); + if (!epittm->base) { + ret = -ENXIO; + goto out_kfree; + } + + epittm->irq = irq_of_parse_and_map(np, 0); + if (!epittm->irq) { + ret = -EINVAL; + goto out_iounmap; + } + + /* Get EPIT clock */ + epittm->clk = of_clk_get(np, 0); + if (IS_ERR(epittm->clk)) { + pr_err("i.MX EPIT: unable to get clk\n"); + ret = PTR_ERR(epittm->clk); + goto out_iounmap; + } + + ret = clk_prepare_enable(epittm->clk); + if (ret) { + pr_err("i.MX EPIT: unable to prepare+enable clk\n"); + goto out_iounmap; + } + + /* Initialise to a known state (all timers off, and timing reset) */ + writel_relaxed(0x0, epittm->base + EPITCR); + writel_relaxed(0xffffffff, epittm->base + EPITLR); + writel_relaxed(EPITCR_EN | EPITCR_CLKSRC_REF_HIGH | EPITCR_WAITEN, + epittm->base + EPITCR); + + ret = epit_clocksource_init(epittm); + if (ret) { + pr_err("i.MX EPIT: failed to init clocksource\n"); + goto out_clk_disable; + } + + ret = epit_clockevent_init(epittm); + if (ret) { + pr_err("i.MX EPIT: failed to init clockevent\n"); + goto out_clk_disable; + } + + return 0; + +out_clk_disable: + clk_disable_unprepare(epittm->clk); +out_iounmap: + iounmap(epittm->base); +out_kfree: + kfree(epittm); + + return ret; +} +TIMER_OF_DECLARE(epit_timer, "fsl,imx31-epit", epit_timer_init); -- 2.17.1