[v3,7/9] clocksource: realtek: Add timer driver for rtl-otto platforms

Message ID	20240627043317.3751996-8-chris.packham@alliedtelesis.co.nz (mailing list archive)
State	Superseded
Headers	show Received: from gate2.alliedtelesis.co.nz (gate2.alliedtelesis.co.nz [202.36.163.20]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3F02320B12 for <linux-mips@vger.kernel.org>; Thu, 27 Jun 2024 04:33:29 +0000 (UTC) From: Chris Packham <chris.packham@alliedtelesis.co.nz> To: tglx@linutronix.de, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, tsbogend@alpha.franken.de, daniel.lezcano@linaro.org, paulburton@kernel.org, peterz@infradead.org, mail@birger-koblitz.de, bert@biot.com, john@phrozen.org, sander@svanheule.net Cc: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-mips@vger.kernel.org, kabel@kernel.org, ericwouds@gmail.com, Chris Packham <chris.packham@alliedtelesis.co.nz>, Markus Stockhausen <markus.stockhausen@gmx.de> Subject: [PATCH v3 7/9] clocksource: realtek: Add timer driver for rtl-otto platforms Date: Thu, 27 Jun 2024 16:33:15 +1200 Message-ID: <20240627043317.3751996-8-chris.packham@alliedtelesis.co.nz> In-Reply-To: <20240627043317.3751996-1-chris.packham@alliedtelesis.co.nz> References: <20240627043317.3751996-1-chris.packham@alliedtelesis.co.nz> Precedence: bulk MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable
Series	mips: Support for RTL9302C \| expand [v3,0/9] mips: Support for RTL9302C [v3,1/9] mips: dts: realtek: use "serial" instead of "uart" in node name [v3,2/9] mips: dts: realtek: add device_type property to cpu node [v3,3/9] dt-bindings: vendor-prefixes: Add Cameo Communications [v3,4/9] dt-bindings: mips: realtek: Add rtl930x-soc compatible [v3,5/9] dt-bindings: timer: Add schema for realtek,otto-timer [v3,6/9] dt-bindings: interrupt-controller: realtek,rtl-intc: Add rtl9300-intc [v3,7/9] clocksource: realtek: Add timer driver for rtl-otto platforms [v3,8/9] mips: generic: add fdt fixup for Realtek reference board [v3,9/9] mips: dts: realtek: Add RTL9302C board

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index 34faa0320ece..70ba57210862 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -134,6 +134,16 @@ config RDA_TIMER help Enables the support for the RDA Micro timer driver. +config REALTEK_OTTO_TIMER + bool "Clocksource/timer for the Realtek Otto platform" + select TIMER_OF + help + This driver adds support for the timers found in the Realtek RTL83xx + and RTL93xx SoCs series. This includes chips such as RTL8380, RTL8381 + and RTL832, as well as chips from the RTL839x series, such as RTL8390 + RT8391, RTL8392, RTL8393 and RTL8396 and chips of the RTL930x series + such as RTL9301, RTL9302 or RTL9303. + config SUN4I_TIMER bool "Sun4i timer driver" if COMPILE_TEST depends on HAS_IOMEM diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index 4bb856e4df55..22743785299e 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -59,6 +59,7 @@ obj-$(CONFIG_MILBEAUT_TIMER) += timer-milbeaut.o obj-$(CONFIG_SPRD_TIMER) += timer-sprd.o obj-$(CONFIG_NPCM7XX_TIMER) += timer-npcm7xx.o obj-$(CONFIG_RDA_TIMER) += timer-rda.o +obj-$(CONFIG_REALTEK_OTTO_TIMER) += timer-rtl-otto.o obj-$(CONFIG_ARC_TIMERS) += arc_timer.o obj-$(CONFIG_ARM_ARCH_TIMER) += arm_arch_timer.o diff --git a/drivers/clocksource/timer-rtl-otto.c b/drivers/clocksource/timer-rtl-otto.c new file mode 100644 index 000000000000..f1b9d35eacd1 --- /dev/null +++ b/drivers/clocksource/timer-rtl-otto.c @@ -0,0 +1,287 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/clk.h> +#include <linux/clockchips.h> +#include <linux/cpu.h> +#include <linux/cpuhotplug.h> +#include <linux/interrupt.h> +#include <linux/sched_clock.h> +#include "timer-of.h" + +#define RTTM_DATA 0x0 +#define RTTM_CNT 0x4 +#define RTTM_CTRL 0x8 +#define RTTM_INT 0xc + +#define RTTM_CTRL_ENABLE BIT(28) +#define RTTM_INT_PENDING BIT(16) +#define RTTM_INT_ENABLE BIT(20) + +/* + * The Otto platform provides multiple 28 bit timers/counters with the following + * operating logic. If enabled the timer counts up. Per timer one can set a + * maximum counter value as an end marker. If end marker is reached the timer + * fires an interrupt. If the timer "overflows" by reaching the end marker or + * by adding 1 to 0x0fffffff the counter is reset to 0. When this happens and + * the timer is in operating mode COUNTER it stops. In mode TIMER it will + * continue to count up. + */ +#define RTTM_CTRL_COUNTER 0 +#define RTTM_CTRL_TIMER BIT(24) + +#define RTTM_BIT_COUNT 28 +#define RTTM_MIN_DELTA 8 +#define RTTM_MAX_DELTA CLOCKSOURCE_MASK(28) + +/* + * Timers are derived from the LXB clock frequency. Usually this is a fixed + * multiple of the 25 MHz oscillator. The 930X SOC is an exception from that. + * Its LXB clock has only dividers and uses the switch PLL of 2.45 GHz as its + * base. The only meaningful frequencies we can achieve from that are 175.000 + * MHz and 153.125 MHz. The greatest common divisor of all explained possible + * speeds is 3125000. Pin the timers to this 3.125 MHz reference frequency. + */ +#define RTTM_TICKS_PER_SEC 3125000 + +struct rttm_cs { + struct timer_of to; + struct clocksource cs; +}; + +/* Simple internal register functions */ +static inline void rttm_set_counter(void __iomem *base, unsigned int counter) +{ + iowrite32(counter, base + RTTM_CNT); +} + +static inline unsigned int rttm_get_counter(void __iomem *base) +{ + return ioread32(base + RTTM_CNT); +} + +static inline void rttm_set_period(void __iomem *base, unsigned int period) +{ + iowrite32(period, base + RTTM_DATA); +} + +static inline void rttm_disable_timer(void __iomem *base) +{ + iowrite32(0, base + RTTM_CTRL); +} + +static inline void rttm_enable_timer(void __iomem *base, u32 mode, u32 divisor) +{ + iowrite32(RTTM_CTRL_ENABLE | mode | divisor, base + RTTM_CTRL); +} + +static inline void rttm_ack_irq(void __iomem *base) +{ + iowrite32(ioread32(base + RTTM_INT) | RTTM_INT_PENDING, base + RTTM_INT); +} + +static inline void rttm_enable_irq(void __iomem *base) +{ + iowrite32(RTTM_INT_ENABLE, base + RTTM_INT); +} + +static inline void rttm_disable_irq(void __iomem *base) +{ + iowrite32(0, base + RTTM_INT); +} + +/* Aggregated control functions for kernel clock framework */ +#define RTTM_DEBUG(base) \ + pr_debug("------------- %d %p\n", \ + smp_processor_id(), base) + +static irqreturn_t rttm_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *clkevt = dev_id; + struct timer_of *to = to_timer_of(clkevt); + + rttm_ack_irq(to->of_base.base); + RTTM_DEBUG(to->of_base.base); + clkevt->event_handler(clkevt); + + return IRQ_HANDLED; +} + +static void rttm_stop_timer(void __iomem *base) +{ + rttm_disable_timer(base); + rttm_ack_irq(base); +} + +static void rttm_start_timer(struct timer_of *to, u32 mode) +{ + rttm_set_counter(to->of_base.base, 0); + rttm_enable_timer(to->of_base.base, mode, to->of_clk.rate / RTTM_TICKS_PER_SEC); +} + +static int rttm_next_event(unsigned long delta, struct clock_event_device *clkevt) +{ + struct timer_of *to = to_timer_of(clkevt); + + RTTM_DEBUG(to->of_base.base); + rttm_stop_timer(to->of_base.base); + rttm_set_period(to->of_base.base, delta); + rttm_start_timer(to, RTTM_CTRL_COUNTER); + + return 0; +} + +static int rttm_state_oneshot(struct clock_event_device *clkevt) +{ + struct timer_of *to = to_timer_of(clkevt); + + RTTM_DEBUG(to->of_base.base); + rttm_stop_timer(to->of_base.base); + rttm_set_period(to->of_base.base, RTTM_TICKS_PER_SEC / HZ); + rttm_start_timer(to, RTTM_CTRL_COUNTER); + + return 0; +} + +static int rttm_state_periodic(struct clock_event_device *clkevt) +{ + struct timer_of *to = to_timer_of(clkevt); + + RTTM_DEBUG(to->of_base.base); + rttm_stop_timer(to->of_base.base); + rttm_set_period(to->of_base.base, RTTM_TICKS_PER_SEC / HZ); + rttm_start_timer(to, RTTM_CTRL_TIMER); + + return 0; +} + +static int rttm_state_shutdown(struct clock_event_device *clkevt) +{ + struct timer_of *to = to_timer_of(clkevt); + + RTTM_DEBUG(to->of_base.base); + rttm_stop_timer(to->of_base.base); + + return 0; +} + +static void rttm_setup_timer(void __iomem *base) +{ + RTTM_DEBUG(base); + rttm_stop_timer(base); + rttm_set_period(base, 0); +} + +static u64 rttm_read_clocksource(struct clocksource *cs) +{ + struct rttm_cs *rcs = container_of(cs, struct rttm_cs, cs); + + return (u64)rttm_get_counter(rcs->to.of_base.base); +} + +/* Module initialization part. */ +static DEFINE_PER_CPU(struct timer_of, rttm_to) = { + .flags = TIMER_OF_BASE | TIMER_OF_CLOCK | TIMER_OF_IRQ, + .of_irq = { + .flags = IRQF_PERCPU | IRQF_TIMER, + .handler = rttm_timer_interrupt, + }, + .clkevt = { + .rating = 400, + .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, + .set_state_periodic = rttm_state_periodic, + .set_state_shutdown = rttm_state_shutdown, + .set_state_oneshot = rttm_state_oneshot, + .set_next_event = rttm_next_event + }, +}; + +static int rttm_enable_clocksource(struct clocksource *cs) +{ + struct rttm_cs *rcs = container_of(cs, struct rttm_cs, cs); + + rttm_disable_irq(rcs->to.of_base.base); + rttm_setup_timer(rcs->to.of_base.base); + rttm_enable_timer(rcs->to.of_base.base, RTTM_CTRL_TIMER, + rcs->to.of_clk.rate / RTTM_TICKS_PER_SEC); + + return 0; +} + +struct rttm_cs rttm_cs = { + .to = { + .flags = TIMER_OF_BASE | TIMER_OF_CLOCK, + }, + .cs = { + .name = "realtek_otto_timer", + .rating = 400, + .mask = CLOCKSOURCE_MASK(RTTM_BIT_COUNT), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, + .read = rttm_read_clocksource, + } +}; + +static u64 notrace rttm_read_clock(void) +{ + return (u64)rttm_get_counter(rttm_cs.to.of_base.base); +} + +static int rttm_cpu_starting(unsigned int cpu) +{ + struct timer_of *to = per_cpu_ptr(&rttm_to, cpu); + + RTTM_DEBUG(to->of_base.base); + to->clkevt.cpumask = cpumask_of(cpu); + irq_force_affinity(to->of_irq.irq, to->clkevt.cpumask); + clockevents_config_and_register(&to->clkevt, RTTM_TICKS_PER_SEC, + RTTM_MIN_DELTA, RTTM_MAX_DELTA); + rttm_enable_irq(to->of_base.base); + + return 0; +} + +static int __init rttm_probe(struct device_node *np) +{ + int cpu, cpu_rollback; + struct timer_of *to; + int clkidx = num_possible_cpus(); + + /* Use the first n timers as per CPU clock event generators */ + for_each_possible_cpu(cpu) { + to = per_cpu_ptr(&rttm_to, cpu); + to->of_irq.index = to->of_base.index = cpu; + if (timer_of_init(np, to)) { + pr_err("setup of timer %d failed\n", cpu); + goto rollback; + } + rttm_setup_timer(to->of_base.base); + } + + /* Activate the n'th + 1 timer as a stable CPU clocksource. */ + to = &rttm_cs.to; + to->of_base.index = clkidx; + timer_of_init(np, to); + if (rttm_cs.to.of_base.base && rttm_cs.to.of_clk.rate) { + rttm_enable_clocksource(&rttm_cs.cs); + clocksource_register_hz(&rttm_cs.cs, RTTM_TICKS_PER_SEC); + sched_clock_register(rttm_read_clock, RTTM_BIT_COUNT, RTTM_TICKS_PER_SEC); + } else + pr_err(" setup of timer %d as clocksource failed", clkidx); + + return cpuhp_setup_state(CPUHP_AP_REALTEK_TIMER_STARTING, + "timer/realtek:online", + rttm_cpu_starting, NULL); +rollback: + pr_err("timer registration failed\n"); + for_each_possible_cpu(cpu_rollback) { + if (cpu_rollback == cpu) + break; + to = per_cpu_ptr(&rttm_to, cpu_rollback); + timer_of_cleanup(to); + } + + return -EINVAL; +} + +TIMER_OF_DECLARE(otto_timer, "realtek,otto-timer", rttm_probe); diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h index 7a5785f405b6..56b744dc1317 100644 --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -171,6 +171,7 @@ enum cpuhp_state { CPUHP_AP_ARMADA_TIMER_STARTING, CPUHP_AP_MIPS_GIC_TIMER_STARTING, CPUHP_AP_ARC_TIMER_STARTING, + CPUHP_AP_REALTEK_TIMER_STARTING, CPUHP_AP_RISCV_TIMER_STARTING, CPUHP_AP_CLINT_TIMER_STARTING, CPUHP_AP_CSKY_TIMER_STARTING,

[v3,7/9] clocksource: realtek: Add timer driver for rtl-otto platforms

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