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From: Bartosz Golaszewski <brgl@bgdev.pl>
To: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Sekhar Nori <nsekhar@ti.com>, Kevin Hilman <khilman@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	David Lechner <david@lechnology.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>
Subject: Re: [RFC v2 1/2] clocksource: davinci-timer: add support for clockevents
Date: Fri, 24 May 2019 09:28:31 +0200	[thread overview]
Message-ID: <CAMRc=MfUFE_yBSqS-s4fVcU9W11Amgeer-eXWNBrkG0Z7KD4tA@mail.gmail.com> (raw)
In-Reply-To: <dbe04cda-4f42-46b5-0808-e756a65180d2@linaro.org>

czw., 23 maj 2019 o 18:38 Daniel Lezcano <daniel.lezcano@linaro.org> napisał(a):
>
> On 23/05/2019 14:58, Bartosz Golaszewski wrote:
> > From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> >
> > Currently the clocksource and clockevent support for davinci platforms
> > lives in mach-davinci. It hard-codes many things, uses global variables,
> > implements functionalities unused by any platform and has code fragments
> > scattered across many (often unrelated) files.
> >
> > Implement a new, modern and simplified timer driver and put it into
> > drivers/clocksource. We still need to support legacy board files so
> > export a config structure and a function that allows machine code to
> > register the timer.
> >
> > The timer we're using is 64-bit but can be programmed in dual 32-bit
> > mode (both chained and unchained). We're using dual 32-bit mode to
> > have separate counters for clockevents and clocksource.
> >
> > This patch contains the core code and support for clockevent. The
> > clocksource code will be included in a subsequent patch.
> >
> > Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> > ---
> >  drivers/clocksource/Kconfig         |   5 +
> >  drivers/clocksource/Makefile        |   1 +
> >  drivers/clocksource/timer-davinci.c | 285 ++++++++++++++++++++++++++++
> >  include/clocksource/timer-davinci.h |  44 +++++
> >  4 files changed, 335 insertions(+)
> >  create mode 100644 drivers/clocksource/timer-davinci.c
> >  create mode 100644 include/clocksource/timer-davinci.h
> >
> > diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
> > index 6bcaa4e2e72c..32dee6abd54a 100644
> > --- a/drivers/clocksource/Kconfig
> > +++ b/drivers/clocksource/Kconfig
> > @@ -42,6 +42,11 @@ config BCM_KONA_TIMER
> >       help
> >         Enables the support for the BCM Kona mobile timer driver.
> >
> > +config DAVINCI_TIMER
> > +     bool "Texas Instruments DaVinci timer driver" if COMPILE_TEST
> > +     help
> > +       Enables the support for the TI DaVinci timer driver.
> > +
> >  config DIGICOLOR_TIMER
> >       bool "Digicolor timer driver" if COMPILE_TEST
> >       select CLKSRC_MMIO
> > diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
> > index 236858fa7fbf..021831bcc567 100644
> > --- a/drivers/clocksource/Makefile
> > +++ b/drivers/clocksource/Makefile
> > @@ -15,6 +15,7 @@ obj-$(CONFIG_SH_TIMER_TMU)  += sh_tmu.o
> >  obj-$(CONFIG_EM_TIMER_STI)   += em_sti.o
> >  obj-$(CONFIG_CLKBLD_I8253)   += i8253.o
> >  obj-$(CONFIG_CLKSRC_MMIO)    += mmio.o
> > +obj-$(CONFIG_DAVINCI_TIMER)  += timer-davinci.o
> >  obj-$(CONFIG_DIGICOLOR_TIMER)        += timer-digicolor.o
> >  obj-$(CONFIG_OMAP_DM_TIMER)  += timer-ti-dm.o
> >  obj-$(CONFIG_DW_APB_TIMER)   += dw_apb_timer.o
> > diff --git a/drivers/clocksource/timer-davinci.c b/drivers/clocksource/timer-davinci.c
> > new file mode 100644
> > index 000000000000..a8fc7b3805c9
> > --- /dev/null
> > +++ b/drivers/clocksource/timer-davinci.c
> > @@ -0,0 +1,285 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * TI DaVinci clocksource driver
> > + *
> > + * Copyright (C) 2019 Texas Instruments
> > + * Author: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> > + * (with tiny parts adopted from code by Kevin Hilman <khilman@baylibre.com>)
> > + */
> > +
> > +#include <linux/clk.h>
> > +#include <linux/clockchips.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/kernel.h>
> > +#include <linux/of_address.h>
> > +#include <linux/of_irq.h>
> > +#include <linux/sched_clock.h>
> > +
> > +#include <clocksource/timer-davinci.h>
> > +
> > +#undef pr_fmt
> > +#define pr_fmt(fmt) "%s: " fmt "\n", __func__
> > +
> > +#define DAVINCI_TIMER_REG_TIM12                      0x10
> > +#define DAVINCI_TIMER_REG_TIM34                      0x14
> > +#define DAVINCI_TIMER_REG_PRD12                      0x18
> > +#define DAVINCI_TIMER_REG_PRD34                      0x1c
> > +#define DAVINCI_TIMER_REG_TCR                        0x20
> > +#define DAVINCI_TIMER_REG_TGCR                       0x24
> > +
> > +#define DAVINCI_TIMER_TIMMODE_MASK           GENMASK(3, 2)
> > +#define DAVINCI_TIMER_RESET_MASK             GENMASK(1, 0)
> > +#define DAVINCI_TIMER_TIMMODE_32BIT_UNCHAINED        BIT(2)
> > +#define DAVINCI_TIMER_UNRESET                        GENMASK(1, 0)
> > +
> > +#define DAVINCI_TIMER_ENAMODE_MASK           GENMASK(1, 0)
> > +#define DAVINCI_TIMER_ENAMODE_DISABLED               0x00
> > +#define DAVINCI_TIMER_ENAMODE_ONESHOT                BIT(0)
> > +
> > +#define DAVINCI_TIMER_ENAMODE_SHIFT_TIM12    6
> > +#define DAVINCI_TIMER_ENAMODE_SHIFT_TIM34    22
> > +
> > +#define DAVINCI_TIMER_MIN_DELTA                      0x01
> > +#define DAVINCI_TIMER_MAX_DELTA                      0xfffffffe
> > +
> > +#define DAVINCI_TIMER_TGCR_DEFAULT \
> > +             (DAVINCI_TIMER_TIMMODE_32BIT_UNCHAINED | DAVINCI_TIMER_UNRESET)
> > +
> > +/* Cache the TCR register value. */
> > +static unsigned int davinci_tcr;
> > +
> > +struct davinci_clockevent {
> > +     struct clock_event_device dev;
> > +     void __iomem *base;
> > +
> > +     unsigned int tim_off;
> > +     unsigned int prd_off;
> > +     unsigned int cmp_off;
> > +
> > +     unsigned int enamode_disabled;
> > +     unsigned int enamode_oneshot;
> > +     unsigned int enamode_mask;
> > +};
> > +
> > +static struct davinci_clockevent *
> > +to_davinci_clockevent(struct clock_event_device *clockevent)
> > +{
> > +     return container_of(clockevent, struct davinci_clockevent, dev);
> > +}
> > +
> > +static unsigned int
> > +davinci_clockevent_read(struct davinci_clockevent *clockevent,
> > +                     unsigned int reg)
> > +{
> > +     return readl_relaxed(clockevent->base + reg);
> > +}
> > +
> > +static void davinci_clockevent_write(struct davinci_clockevent *clockevent,
> > +                                  unsigned int reg, unsigned int val)
> > +{
> > +     writel_relaxed(val, clockevent->base + reg);
> > +}
> > +
> > +static void davinci_tcr_update(void __iomem *base,
> > +                            unsigned int mask, unsigned int val)
> > +{
> > +     davinci_tcr &= ~mask;
> > +     davinci_tcr |= val & mask;
>
>
> I don't see when the davinci_tcr is initialized.
>

It's set to 0x0 by the compiler and we're setting the register to 0x0
in davinci_timer_init().

Bart

> > +     writel_relaxed(davinci_tcr, base + DAVINCI_TIMER_REG_TCR);
> > +}
> > +
> > +static int davinci_clockevent_shutdown(struct clock_event_device *dev)
> > +{
> > +     struct davinci_clockevent *clockevent;
> > +
> > +     clockevent = to_davinci_clockevent(dev);
> > +
> > +     davinci_tcr_update(clockevent->base,
> > +                        clockevent->enamode_mask,
> > +                        clockevent->enamode_disabled);
> > +
> > +     return 0;
> > +}
> > +
> > +static int davinci_clockevent_set_oneshot(struct clock_event_device *dev)
> > +{
> > +     struct davinci_clockevent *clockevent = to_davinci_clockevent(dev);
> > +
> > +     davinci_clockevent_write(clockevent, clockevent->tim_off, 0x0);
> > +
> > +     davinci_tcr_update(clockevent->base,
> > +                        clockevent->enamode_mask,
> > +                        clockevent->enamode_oneshot);
> > +
> > +     return 0;
> > +}
> > +
> > +static int
> > +davinci_clockevent_set_next_event_std(unsigned long cycles,
> > +                                   struct clock_event_device *dev)
> > +{
> > +     struct davinci_clockevent *clockevent = to_davinci_clockevent(dev);
> > +
> > +     davinci_clockevent_shutdown(dev);
> > +
> > +     davinci_clockevent_write(clockevent, clockevent->tim_off, 0x0);
> > +     davinci_clockevent_write(clockevent, clockevent->prd_off, cycles);
> > +
> > +     davinci_clockevent_set_oneshot(dev);
> > +
> > +     return 0;
> > +}
> > +
> > +static int
> > +davinci_clockevent_set_next_event_cmp(unsigned long cycles,
> > +                                   struct clock_event_device *dev)
> > +{
> > +     struct davinci_clockevent *clockevent = to_davinci_clockevent(dev);
> > +     unsigned int curr_time;
> > +
> > +     curr_time = davinci_clockevent_read(clockevent, clockevent->tim_off);
> > +     davinci_clockevent_write(clockevent,
> > +                              clockevent->cmp_off, curr_time + cycles);
> > +
> > +     return 0;
> > +}
> > +
> > +static irqreturn_t davinci_timer_irq_timer(int irq, void *data)
> > +{
> > +     struct davinci_clockevent *clockevent = data;
> > +
> > +     if (!clockevent_state_oneshot(&clockevent->dev))
> > +             davinci_tcr_update(clockevent,
> > +                                clockevent->enamode_mask,
> > +                                clockevent->enamode_disabled);
> > +
> > +     clockevent->dev.event_handler(&clockevent->dev);
> > +
> > +     return IRQ_HANDLED;
> > +}
> > +
> > +static void davinci_timer_init(void __iomem *base)
> > +{
> > +     /* Set clock to internal mode and disable it. */
> > +     writel_relaxed(0x0, base + DAVINCI_TIMER_REG_TCR);
> > +     /*
> > +      * Reset both 32-bit timers, set no prescaler for timer 34, set the
> > +      * timer to dual 32-bit unchained mode, unreset both 32-bit timers.
> > +      */
> > +     writel_relaxed(DAVINCI_TIMER_TGCR_DEFAULT,
> > +                    base + DAVINCI_TIMER_REG_TGCR);
> > +     /* Init both counters to zero. */
> > +     writel_relaxed(0x0, base + DAVINCI_TIMER_REG_TIM12);
> > +     writel_relaxed(0x0, base + DAVINCI_TIMER_REG_TIM34);
> > +}
> > +
> > +int __init davinci_timer_register(struct clk *clk,
> > +                               const struct davinci_timer_cfg *timer_cfg)
> > +{
> > +     struct davinci_clockevent *clockevent;
> > +     unsigned int tick_rate, shift;
> > +     void __iomem *base;
> > +     int rv;
> > +
> > +     rv = clk_prepare_enable(clk);
> > +     if (rv) {
> > +             pr_err("Unable to prepare and enable the timer clock");
> > +             return rv;
> > +     }
> > +
> > +     base = request_mem_region(timer_cfg->reg.start,
> > +                               resource_size(&timer_cfg->reg),
> > +                               "davinci-timer");
> > +     if (!base) {
> > +             pr_err("Unable to request memory region");
> > +             return -EBUSY;
> > +     }
> > +
> > +     base = ioremap(timer_cfg->reg.start, resource_size(&timer_cfg->reg));
> > +     if (!base) {
> > +             pr_err("Unable to map the register range");
> > +             return -ENOMEM;
> > +     }
> > +
> > +     davinci_timer_init(base);
> > +     tick_rate = clk_get_rate(clk);
> > +
> > +     clockevent = kzalloc(sizeof(*clockevent), GFP_KERNEL);
> > +     if (!clockevent) {
> > +             pr_err("Error allocating memory for clockevent data");
> > +             return -ENOMEM;
> > +     }
> > +
> > +     clockevent->dev.name = "tim12";
> > +     clockevent->dev.features = CLOCK_EVT_FEAT_ONESHOT;
> > +     clockevent->dev.cpumask = cpumask_of(0);
> > +
> > +     clockevent->base = base;
> > +     clockevent->tim_off = DAVINCI_TIMER_REG_TIM12;
> > +     clockevent->prd_off = DAVINCI_TIMER_REG_PRD12;
> > +
> > +     shift = DAVINCI_TIMER_ENAMODE_SHIFT_TIM12;
> > +     clockevent->enamode_disabled = DAVINCI_TIMER_ENAMODE_DISABLED << shift;
> > +     clockevent->enamode_oneshot = DAVINCI_TIMER_ENAMODE_ONESHOT << shift;
> > +     clockevent->enamode_mask = DAVINCI_TIMER_ENAMODE_MASK << shift;
> > +
> > +     clockevent->dev.set_state_shutdown = davinci_clockevent_shutdown;
> > +     clockevent->dev.set_state_oneshot = davinci_clockevent_set_oneshot;
> > +
> > +     if (timer_cfg->cmp_off) {
> > +             clockevent->cmp_off = timer_cfg->cmp_off;
> > +             clockevent->dev.set_next_event =
> > +                             davinci_clockevent_set_next_event_cmp;
> > +     } else {
> > +             clockevent->dev.set_next_event =
> > +                             davinci_clockevent_set_next_event_std;
> > +     }
> > +
> > +     rv = request_irq(timer_cfg->irq[DAVINCI_TIMER_CLOCKEVENT_IRQ].start,
> > +                      davinci_timer_irq_timer, IRQF_TIMER,
> > +                      "clockevent", clockevent);
> > +     if (rv) {
> > +             pr_err("Unable to request the clockevent interrupt");
> > +             return rv;
> > +     }
> > +
> > +     clockevents_config_and_register(&clockevent->dev, tick_rate,
> > +                                     DAVINCI_TIMER_MIN_DELTA,
> > +                                     DAVINCI_TIMER_MAX_DELTA);
> > +
> > +     return 0;
> > +}
> > +
> > +static int __init of_davinci_timer_register(struct device_node *np)
> > +{
> > +     struct davinci_timer_cfg timer_cfg = { };
> > +     struct clk *clk;
> > +     int rv;
> > +
> > +     rv = of_address_to_resource(np, 0, &timer_cfg.reg);
> > +     if (rv) {
> > +             pr_err("Unable to get the register range for timer");
> > +             return rv;
> > +     }
> > +
> > +     rv = of_irq_to_resource_table(np, timer_cfg.irq,
> > +                                   DAVINCI_TIMER_NUM_IRQS);
> > +     if (rv != DAVINCI_TIMER_NUM_IRQS) {
> > +             pr_err("Unable to get the interrupts for timer");
> > +             return rv;
> > +     }
> > +
> > +     clk = of_clk_get(np, 0);
> > +     if (IS_ERR(clk)) {
> > +             pr_err("Unable to get the timer clock");
> > +             return PTR_ERR(clk);
> > +     }
> > +
> > +     rv = davinci_timer_register(clk, &timer_cfg);
> > +     if (rv)
> > +             clk_put(clk);
> > +
> > +     return rv;
> > +}
> > +TIMER_OF_DECLARE(davinci_timer, "ti,da830-timer", of_davinci_timer_register);
> > diff --git a/include/clocksource/timer-davinci.h b/include/clocksource/timer-davinci.h
> > new file mode 100644
> > index 000000000000..1dcc1333fbc8
> > --- /dev/null
> > +++ b/include/clocksource/timer-davinci.h
> > @@ -0,0 +1,44 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only */
> > +/*
> > + * TI DaVinci clocksource driver
> > + *
> > + * Copyright (C) 2019 Texas Instruments
> > + * Author: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> > + */
> > +
> > +#ifndef __TIMER_DAVINCI_H__
> > +#define __TIMER_DAVINCI_H__
> > +
> > +#include <linux/clk.h>
> > +#include <linux/ioport.h>
> > +
> > +enum {
> > +     DAVINCI_TIMER_CLOCKEVENT_IRQ,
> > +     DAVINCI_TIMER_CLOCKSOURCE_IRQ,
> > +     DAVINCI_TIMER_NUM_IRQS,
> > +};
> > +
> > +/**
> > + * struct davinci_timer_cfg - davinci clocksource driver configuration struct
> > + * @reg:        register range resource
> > + * @irq:        clockevent and clocksource interrupt resources
> > + * @cmp_off:    if set - it specifies the compare register used for clockevent
> > + *
> > + * Note: if the compare register is specified, the driver will use the bottom
> > + * clock half for both clocksource and clockevent and the compare register
> > + * to generate event irqs. The user must supply the correct compare register
> > + * interrupt number.
> > + *
> > + * This is only used by da830 the DSP of which uses the top half. The timer
> > + * driver still configures the top half to run in free-run mode.
> > + */
> > +struct davinci_timer_cfg {
> > +     struct resource reg;
> > +     struct resource irq[DAVINCI_TIMER_NUM_IRQS];
> > +     unsigned int cmp_off;
> > +};
> > +
> > +int __init davinci_timer_register(struct clk *clk,
> > +                               const struct davinci_timer_cfg *data);
> > +
> > +#endif /* __TIMER_DAVINCI_H__ */
> >
>
>
> --
>  <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs
>
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>

  reply	other threads:[~2019-05-24  7:28 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-23 12:58 [RFC v2 0/2] clocksource: davinci-timer: new driver Bartosz Golaszewski
2019-05-23 12:58 ` [RFC v2 1/2] clocksource: davinci-timer: add support for clockevents Bartosz Golaszewski
2019-05-23 16:38   ` Daniel Lezcano
2019-05-24  7:28     ` Bartosz Golaszewski [this message]
2019-05-24  8:59       ` Daniel Lezcano
2019-05-24 11:53         ` Bartosz Golaszewski
2019-05-25 14:16           ` Daniel Lezcano
2019-05-26  8:16             ` Bartosz Golaszewski
2019-05-31 12:21               ` Bartosz Golaszewski
2019-05-23 12:58 ` [RFC v2 2/2] clocksource: timer-davinci: add support for clocksource Bartosz Golaszewski

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