From: Daniel Lezcano <daniel.lezcano@linaro.org>
To: nikita.shubin@maquefel.me, Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
Alexander Sverdlin <alexander.sverdlin@gmail.com>
Subject: Re: [PATCH v4 12/42] clocksource: ep93xx: Add driver for Cirrus Logic EP93xx
Date: Wed, 11 Oct 2023 15:30:13 +0200 [thread overview]
Message-ID: <d72a893a-a473-4399-8e87-5fedffe3ca40@linaro.org> (raw)
In-Reply-To: <20230915-ep93xx-v4-12-a1d779dcec10@maquefel.me>
On 15/09/2023 10:10, Nikita Shubin via B4 Relay wrote:
> From: Nikita Shubin <nikita.shubin@maquefel.me>
>
> Rewrite EP93xx timer driver located in arch/arm/mach-ep93xx/timer-ep93xx.c
> trying to do everything the device tree way:
>
> - Make every IO-access relative to a base address and dynamic
> so we can do a dynamic ioremap and get going.
> - Find register range and interrupt from the device tree.
>
> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
> Tested-by: Alexander Sverdlin <alexander.sverdlin@gmail.com>
> Signed-off-by: Nikita Shubin <nikita.shubin@maquefel.me>
> ---
> drivers/clocksource/Kconfig | 11 +++
> drivers/clocksource/Makefile | 1 +
> drivers/clocksource/timer-ep93xx.c | 190 +++++++++++++++++++++++++++++++++++++
> 3 files changed, 202 insertions(+)
>
> diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
> index c4d671a5a13d..f1b84b05b281 100644
> --- a/drivers/clocksource/Kconfig
> +++ b/drivers/clocksource/Kconfig
> @@ -739,4 +739,15 @@ config GOLDFISH_TIMER
> help
> Support for the timer/counter of goldfish-rtc
>
> +config EP93XX_TIMER
> + bool "Cirrus Logic ep93xx timer driver" if COMPILE_TEST
> + depends on ARCH_EP93XX
Remove this dependency so it would be possible to compile-test on other
platforms.
> + depends on GENERIC_CLOCKEVENTS
This dependency is explicit for all the drivers belonging to this
Kconfig. No need to add it.
> + depends on HAS_IOMEM
> + select CLKSRC_MMIO
> + select TIMER_OF
> + help
> + Enables support for the Cirrus Logic timer block
> + EP93XX.
> +
> endmenu
> diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
> index 5d93c9e3fc55..b6a3cf1f5b9d 100644
> --- a/drivers/clocksource/Makefile
> +++ b/drivers/clocksource/Makefile
> @@ -90,3 +90,4 @@ obj-$(CONFIG_MSC313E_TIMER) += timer-msc313e.o
> obj-$(CONFIG_GOLDFISH_TIMER) += timer-goldfish.o
> obj-$(CONFIG_GXP_TIMER) += timer-gxp.o
> obj-$(CONFIG_CLKSRC_LOONGSON1_PWM) += timer-loongson1-pwm.o
> +obj-$(CONFIG_EP93XX_TIMER) += timer-ep93xx.o
> diff --git a/drivers/clocksource/timer-ep93xx.c b/drivers/clocksource/timer-ep93xx.c
> new file mode 100644
> index 000000000000..bc0ca6e12334
> --- /dev/null
> +++ b/drivers/clocksource/timer-ep93xx.c
> @@ -0,0 +1,190 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Cirrus Logic EP93xx timer driver.
> + * Copyright (C) 2021 Nikita Shubin <nikita.shubin@maquefel.me>
> + *
> + * Based on a rewrite of arch/arm/mach-ep93xx/timer.c:
> + */
> +
> +#include <linux/clockchips.h>
> +#include <linux/clocksource.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/io-64-nonatomic-lo-hi.h>
> +#include <linux/irq.h>
> +#include <linux/kernel.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/sched_clock.h>
> +
> +#include <asm/mach/time.h>
This head should not be needed.
> +
> +/*************************************************************************
> + * Timer handling for EP93xx
> + *************************************************************************
> + * The ep93xx has four internal timers. Timers 1, 2 (both 16 bit) and
> + * 3 (32 bit) count down at 508 kHz, are self-reloading, and can generate
> + * an interrupt on underflow. Timer 4 (40 bit) counts down at 983.04 kHz,
> + * is free-running, and can't generate interrupts.
> + *
> + * The 508 kHz timers are ideal for use for the timer interrupt, as the
> + * most common values of HZ divide 508 kHz nicely. We pick the 32 bit
> + * timer (timer 3) to get as long sleep intervals as possible when using
> + * CONFIG_NO_HZ.
> + *
> + * The higher clock rate of timer 4 makes it a better choice than the
> + * other timers for use as clock source and for sched_clock(), providing
> + * a stable 40 bit time base.
> + *************************************************************************
> + */
> +
> +#define EP93XX_TIMER1_LOAD 0x00
> +#define EP93XX_TIMER1_VALUE 0x04
> +#define EP93XX_TIMER1_CONTROL 0x08
> +#define EP93XX_TIMER123_CONTROL_ENABLE BIT(7)
> +#define EP93XX_TIMER123_CONTROL_MODE BIT(6)
> +#define EP93XX_TIMER123_CONTROL_CLKSEL BIT(3)
> +#define EP93XX_TIMER1_CLEAR 0x0c
> +#define EP93XX_TIMER2_LOAD 0x20
> +#define EP93XX_TIMER2_VALUE 0x24
> +#define EP93XX_TIMER2_CONTROL 0x28
> +#define EP93XX_TIMER2_CLEAR 0x2c
> +/*
> + * This read-only register contains the low word of the time stamp debug timer
> + * ( Timer4). When this register is read, the high byte of the Timer4 counter is
> + * saved in the Timer4ValueHigh register.
> + */
> +#define EP93XX_TIMER4_VALUE_LOW 0x60
> +#define EP93XX_TIMER4_VALUE_HIGH 0x64
> +#define EP93XX_TIMER4_VALUE_HIGH_ENABLE BIT(8)
> +#define EP93XX_TIMER3_LOAD 0x80
> +#define EP93XX_TIMER3_VALUE 0x84
> +#define EP93XX_TIMER3_CONTROL 0x88
> +#define EP93XX_TIMER3_CLEAR 0x8c
> +
> +#define EP93XX_TIMER123_RATE 508469
> +#define EP93XX_TIMER4_RATE 983040
> +
> +struct ep93xx_tcu {
> + void __iomem *base;
> +};
> +
> +static struct ep93xx_tcu *ep93xx_tcu;
Usually what is done is:
struct ep93xx_tcu {
void __iomem *base;
struct clock_event_device evt;
};
And with container_of and all timer API passing the *evt as parameter,
we can retrieve this data.
So we should have:
struct ep93xx_tcu timer = {
.evt = {
.name = "timer1",
.features = CLOCK_EVT_FEAT_ONESHOT,
.set_state_shutdown = ep93xx_clkevt_shutdown,
.set_state_oneshot = ep93xx_clkevt_shutdown,
.tick_resume = ep93xx_clkevt_shutdown,
.set_next_event = ep93xx_clkevt_set_next_event,
.rating = 300,
};
/* No need to compute every time */
void __iomem *clksrc_base; /* base + timer4_val_low */
void __iomem *clkevt_base;
};
And no need to allocate in the init function.
> +static u64 ep93xx_clocksource_read(struct clocksource *c)
Perhaps add __may_be_unused annotation
> +{
> + struct ep93xx_tcu *tcu = ep93xx_tcu;
> +
> + return lo_hi_readq(tcu->base + EP93XX_TIMER4_VALUE_LOW) & GENMASK_ULL(39, 0);
> +}
> +
> +static u64 notrace ep93xx_read_sched_clock(void)
> +{
> + return ep93xx_clocksource_read(NULL);
> +}
> +static int ep93xx_clkevt_set_next_event(unsigned long next,
> + struct clock_event_device *evt)
> +{
> + struct ep93xx_tcu *tcu = ep93xx_tcu;
> + /* Default mode: periodic, off, 508 kHz */
> + u32 tmode = EP93XX_TIMER123_CONTROL_MODE |
> + EP93XX_TIMER123_CONTROL_CLKSEL;
> +
> + /* Clear timer */
> + writel(tmode, tcu->base + EP93XX_TIMER3_CONTROL);
> +
> + /* Set next event */
> + writel(next, tcu->base + EP93XX_TIMER3_LOAD);
> + writel(tmode | EP93XX_TIMER123_CONTROL_ENABLE,
> + tcu->base + EP93XX_TIMER3_CONTROL);
> + return 0;
> +}
> +
> +static int ep93xx_clkevt_shutdown(struct clock_event_device *evt)
> +{
> + struct ep93xx_tcu *tcu = ep93xx_tcu;
> + /* Disable timer */
> + writel(0, tcu->base + EP93XX_TIMER3_CONTROL);
> +
> + return 0;
> +}
> +
> +static struct clock_event_device ep93xx_clockevent = {
> + .name = "timer1",
> + .features = CLOCK_EVT_FEAT_ONESHOT,
> + .set_state_shutdown = ep93xx_clkevt_shutdown,
> + .set_state_oneshot = ep93xx_clkevt_shutdown,
> + .tick_resume = ep93xx_clkevt_shutdown,
> + .set_next_event = ep93xx_clkevt_set_next_event,
> + .rating = 300,
> +};
> +
> +static irqreturn_t ep93xx_timer_interrupt(int irq, void *dev_id)
> +{
> + struct ep93xx_tcu *tcu = ep93xx_tcu;
> + struct clock_event_device *evt = dev_id;
> +
> + /* Writing any value clears the timer interrupt */
> + writel(1, tcu->base + EP93XX_TIMER3_CLEAR);
> +
> + evt->event_handler(evt);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int __init ep93xx_timer_of_init(struct device_node *np)
> +{
> + int irq;
> + unsigned long flags = IRQF_TIMER | IRQF_IRQPOLL;
> + struct ep93xx_tcu *tcu;
> + int ret;
> +
> + tcu = kzalloc(sizeof(*tcu), GFP_KERNEL);
> + if (!tcu)
> + return -ENOMEM;
> +
> + tcu->base = of_iomap(np, 0);
> + if (!tcu->base) {
> + pr_err("Can't remap registers\n");
> + ret = -ENXIO;
> + goto out_free;
> + }
> +
> + ep93xx_tcu = tcu;
> +
> + irq = irq_of_parse_and_map(np, 0);
> + if (irq == 0)
> + irq = -EINVAL;
> + if (irq < 0) {
> + pr_err("EP93XX Timer Can't parse IRQ %d", irq);
> + goto out_free;
> + }
> +
> + /* Enable and register clocksource and sched_clock on timer 4 */
> + writel(EP93XX_TIMER4_VALUE_HIGH_ENABLE,
> + tcu->base + EP93XX_TIMER4_VALUE_HIGH);
> + clocksource_mmio_init(NULL, "timer4",
> + EP93XX_TIMER4_RATE, 200, 40,
> + ep93xx_clocksource_read);
return code check
> + sched_clock_register(ep93xx_read_sched_clock, 40,
> + EP93XX_TIMER4_RATE);
> +
> + /* Set up clockevent on timer 3 */
> + if (request_irq(irq, ep93xx_timer_interrupt, flags, "ep93xx timer",
> + &ep93xx_clockevent))
> + pr_err("Failed to request irq %d (ep93xx timer)\n", irq);
return error
> + clockevents_config_and_register(&ep93xx_clockevent,
> + EP93XX_TIMER123_RATE,
> + 1,
> + UINT_MAX);
> +
> + return 0;
> +
> +out_free:
> + kfree(tcu);
> + return ret;
> +}
> +TIMER_OF_DECLARE(ep93xx_timer, "cirrus,ep9301-timer", ep93xx_timer_of_init);
>
--
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next prev parent reply other threads:[~2023-10-11 13:30 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-15 8:10 [PATCH v4 00/42] ep93xx device tree conversion Nikita Shubin via B4 Relay
2023-09-15 8:10 ` [PATCH v4 01/42] gpio: ep93xx: split device in multiple Nikita Shubin via B4 Relay
2023-09-18 7:37 ` Andy Shevchenko
2023-09-15 8:10 ` [PATCH v4 02/42] ARM: ep93xx: add swlocked prototypes Nikita Shubin via B4 Relay
2023-09-16 15:38 ` Alexander Sverdlin
2023-09-18 13:04 ` Alexander Sverdlin
2023-09-15 8:10 ` [PATCH v4 03/42] dt-bindings: clock: Add Cirrus EP93xx Nikita Shubin via B4 Relay
2023-09-15 10:36 ` Krzysztof Kozlowski
2023-09-15 8:10 ` [PATCH v4 04/42] clk: ep93xx: add DT support for " Nikita Shubin via B4 Relay
2023-10-24 2:50 ` Stephen Boyd
2023-09-15 8:10 ` [PATCH v4 05/42] dt-bindings: pinctrl: Add " Nikita Shubin via B4 Relay
2023-09-15 10:37 ` Krzysztof Kozlowski
2023-09-15 8:10 ` [PATCH v4 06/42] pinctrl: add a Cirrus ep93xx SoC pin controller Nikita Shubin via B4 Relay
2023-09-15 8:10 ` [PATCH v4 07/42] dt-bindings: power: reset: Add ep93xx reset Nikita Shubin via B4 Relay
2023-09-15 10:39 ` Krzysztof Kozlowski
2023-09-15 8:10 ` [PATCH v4 08/42] power: reset: Add a driver for the " Nikita Shubin via B4 Relay
2023-09-15 8:10 ` [PATCH v4 09/42] dt-bindings: soc: Add Cirrus EP93xx Nikita Shubin via B4 Relay
2023-09-15 10:42 ` Krzysztof Kozlowski
2023-09-15 8:10 ` [PATCH v4 10/42] soc: Add SoC driver for Cirrus ep93xx Nikita Shubin via B4 Relay
2023-09-15 8:10 ` [PATCH v4 11/42] dt-bindings: timers: Add Cirrus EP93xx Nikita Shubin via B4 Relay
2023-10-15 21:40 ` Daniel Lezcano
2023-10-27 18:23 ` [tip: timers/core] " tip-bot2 for Nikita Shubin
2023-09-15 8:10 ` [PATCH v4 12/42] clocksource: ep93xx: Add driver for Cirrus Logic EP93xx Nikita Shubin via B4 Relay
2023-10-11 13:30 ` Daniel Lezcano [this message]
2023-10-15 21:40 ` Daniel Lezcano
2023-10-27 18:23 ` [tip: timers/core] " tip-bot2 for Nikita Shubin
2023-09-15 8:10 ` [PATCH v4 13/42] dt-bindings: rtc: Add Cirrus EP93xx Nikita Shubin via B4 Relay
2023-09-15 10:43 ` Krzysztof Kozlowski
2023-09-15 8:10 ` [PATCH v4 14/42] rtc: ep93xx: add DT support for " Nikita Shubin via B4 Relay
2023-09-15 8:10 ` [PATCH v4 15/42] dt-bindings: watchdog: Add Cirrus EP93x Nikita Shubin via B4 Relay
2023-09-15 10:43 ` Krzysztof Kozlowski
2023-09-15 8:10 ` [PATCH v4 16/42] watchdog: ep93xx: add DT support for Cirrus EP93xx Nikita Shubin via B4 Relay
2023-09-15 8:10 ` [PATCH v4 17/42] dt-bindings: pwm: Add " Nikita Shubin via B4 Relay
2023-09-15 10:45 ` Krzysztof Kozlowski
2023-09-15 8:11 ` [PATCH v4 18/42] pwm: ep93xx: add DT support for " Nikita Shubin via B4 Relay
2023-09-15 10:43 ` Uwe Kleine-König
2023-09-15 8:11 ` [PATCH v4 19/42] dt-bindings: spi: Add " Nikita Shubin via B4 Relay
2023-09-15 10:47 ` Krzysztof Kozlowski
2023-09-15 8:11 ` [PATCH v4 20/42] spi: ep93xx: add DT support for " Nikita Shubin via B4 Relay
2023-09-15 12:38 ` Mark Brown
2023-09-15 8:11 ` [PATCH v4 21/42] dt-bindings: net: Add " Nikita Shubin via B4 Relay
2023-09-15 10:49 ` Krzysztof Kozlowski
2023-09-15 8:11 ` [PATCH v4 22/42] net: cirrus: add DT support for " Nikita Shubin via B4 Relay
2023-09-15 8:11 ` [PATCH v4 23/42] dt-bindings: dma: Add " Nikita Shubin via B4 Relay
2023-09-15 10:58 ` Krzysztof Kozlowski
2023-09-15 8:11 ` [PATCH v4 24/42] dma: cirrus: add DT support for " Nikita Shubin via B4 Relay
2023-09-15 8:11 ` [PATCH v4 25/42] dt-bindings: mtd: Add ts7200 nand-controller Nikita Shubin via B4 Relay
2023-09-15 11:00 ` Krzysztof Kozlowski
2023-09-15 8:11 ` [PATCH v4 26/42] mtd: nand: add support for ts72xx Nikita Shubin via B4 Relay
2023-09-18 12:58 ` Miquel Raynal
2023-09-15 8:11 ` [PATCH v4 27/42] dt-bindings: ata: Add Cirrus EP93xx Nikita Shubin via B4 Relay
2023-09-15 11:00 ` Krzysztof Kozlowski
2023-09-15 8:11 ` [PATCH v4 28/42] ata: pata_ep93xx: add device tree support Nikita Shubin via B4 Relay
2023-09-15 8:17 ` Damien Le Moal
2023-09-15 8:53 ` Sergey Shtylyov
2023-09-15 8:11 ` [PATCH v4 29/42] dt-bindings: input: Add Cirrus EP93xx keypad Nikita Shubin via B4 Relay
2023-09-15 11:05 ` Krzysztof Kozlowski
2023-09-15 8:11 ` [PATCH v4 30/42] input: keypad: ep93xx: add DT support for Cirrus EP93xx Nikita Shubin via B4 Relay
2023-09-18 7:27 ` Andy Shevchenko
2023-09-15 8:11 ` [PATCH v4 31/42] dt-bindings: wdt: Add ts72xx Nikita Shubin via B4 Relay
2023-09-15 11:18 ` Krzysztof Kozlowski
2023-09-15 8:11 ` [PATCH v4 32/42] wdt: ts72xx: add DT support for ts72xx Nikita Shubin via B4 Relay
2023-09-15 8:11 ` [PATCH v4 33/42] gpio: ep93xx: add DT support for gpio-ep93xx Nikita Shubin via B4 Relay
2023-09-15 8:11 ` [PATCH v4 34/42] ARM: dts: add Cirrus EP93XX SoC .dtsi Nikita Shubin via B4 Relay
2023-09-15 11:24 ` Krzysztof Kozlowski
2023-09-15 8:11 ` [PATCH v4 35/42] ARM: dts: ep93xx: add ts7250 board Nikita Shubin via B4 Relay
2023-09-15 8:11 ` [PATCH v4 36/42] ARM: ep93xx: DT for the Cirrus ep93xx SoC platforms Nikita Shubin via B4 Relay
2023-09-15 8:11 ` [PATCH v4 37/42] pwm: ep93xx: drop legacy pinctrl Nikita Shubin via B4 Relay
2023-09-15 8:46 ` Linus Walleij
2023-09-15 8:11 ` [PATCH v4 38/42] ata: pata_ep93xx: remove legacy pinctrl use Nikita Shubin via B4 Relay
2023-09-15 8:47 ` Linus Walleij
2023-09-15 8:11 ` [PATCH v4 39/42] ARM: ep93xx: delete all boardfiles Nikita Shubin via B4 Relay
2023-09-15 8:11 ` [PATCH v4 40/42] ARM: ep93xx: soc: drop defines Nikita Shubin via B4 Relay
2023-09-15 8:11 ` [PATCH v4 41/42] ARM: dts: ep93xx: Add EDB9302 DT Nikita Shubin via B4 Relay
2023-09-15 8:11 ` [PATCH v4 42/42] ASoC: cirrus: edb93xx: Delete driver Nikita Shubin via B4 Relay
2023-09-15 12:26 ` Mark Brown
2023-09-18 7:39 ` [PATCH v4 00/42] ep93xx device tree conversion Andy Shevchenko
2023-10-15 21:17 ` (subset) " Alexandre Belloni
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