From: Hao-Wen Ting Date: Wed, 26 Nov 2025 06:01:10 +0000 (+0800) Subject: clocksource/drivers: Add Realtek system timer driver X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d1780dce9575072303b9c574614b72b5c8c5c44c;p=thirdparty%2Flinux.git clocksource/drivers: Add Realtek system timer driver Add a system timer driver for Realtek SoCs. This driver registers the 1 MHz global hardware counter on Realtek platforms as a clock event device. Since this hardware counter starts counting automatically after SoC power-on, no clock initialization is required. Because the counter does not stop or get affected by CPU power down, and it supports oneshot mode, it is typically used as a tick broadcast timer. Signed-off-by: Hao-Wen Ting Signed-off-by: Daniel Lezcano Acked-by: Thomas Gleixner Link: https://patch.msgid.link/20251126060110.198330-3-haowen.ting@realtek.com --- diff --git a/MAINTAINERS b/MAINTAINERS index 3da2c26a796b8..b72b9873b90e9 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -21669,6 +21669,11 @@ S: Maintained F: Documentation/devicetree/bindings/spi/realtek,rtl9301-snand.yaml F: drivers/spi/spi-realtek-rtl-snand.c +REALTEK SYSTIMER DRIVER +M: Hao-Wen Ting +S: Maintained +F: drivers/clocksource/timer-realtek.c + REALTEK WIRELESS DRIVER (rtlwifi family) M: Ping-Ke Shih L: linux-wireless@vger.kernel.org diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index ffcd23668763f..aa59e5b133510 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -782,4 +782,15 @@ config NXP_STM_TIMER Enables the support for NXP System Timer Module found in the s32g NXP platform series. +config RTK_SYSTIMER + bool "Realtek SYSTIMER support" + depends on ARM || ARM64 + depends on ARCH_REALTEK || COMPILE_TEST + select TIMER_OF + help + This option enables the driver that registers the global 1 MHz hardware + counter as a clock event device on Realtek SoCs. Make sure to enable + this option only when building for a Realtek platform or for compilation + testing. + endmenu diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index ec4452ee958f1..b46376af6b490 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -95,3 +95,4 @@ obj-$(CONFIG_CLKSRC_LOONGSON1_PWM) += timer-loongson1-pwm.o obj-$(CONFIG_EP93XX_TIMER) += timer-ep93xx.o obj-$(CONFIG_RALINK_TIMER) += timer-ralink.o obj-$(CONFIG_NXP_STM_TIMER) += timer-nxp-stm.o +obj-$(CONFIG_RTK_SYSTIMER) += timer-realtek.o diff --git a/drivers/clocksource/timer-realtek.c b/drivers/clocksource/timer-realtek.c new file mode 100644 index 0000000000000..4f0439de99396 --- /dev/null +++ b/drivers/clocksource/timer-realtek.c @@ -0,0 +1,150 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2025 Realtek Semiconductor Corp. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include "timer-of.h" + +#define ENBL 1 +#define DSBL 0 + +#define SYSTIMER_RATE 1000000 +#define SYSTIMER_MIN_DELTA 0x64 +#define SYSTIMER_MAX_DELTA ULONG_MAX + +/* SYSTIMER Register Offset (RTK Internal Use) */ +#define TS_LW_OFST 0x0 +#define TS_HW_OFST 0x4 +#define TS_CMP_VAL_LW_OFST 0x8 +#define TS_CMP_VAL_HW_OFST 0xC +#define TS_CMP_CTRL_OFST 0x10 +#define TS_CMP_STAT_OFST 0x14 + +/* SYSTIMER CMP CTRL REG Mask */ +#define TS_CMP_EN_MASK 0x1 +#define TS_WR_EN0_MASK 0x2 + +static void __iomem *systimer_base; + +static u64 rtk_ts64_read(void) +{ + u32 low, high; + u64 ts; + + /* Caution: Read LSB word (TS_LW_OFST) first then MSB (TS_HW_OFST) */ + low = readl(systimer_base + TS_LW_OFST); + high = readl(systimer_base + TS_HW_OFST); + ts = ((u64)high << 32) | low; + + return ts; +} + +static void rtk_cmp_value_write(u64 value) +{ + u32 high, low; + + low = value & 0xFFFFFFFF; + high = value >> 32; + + writel(high, systimer_base + TS_CMP_VAL_HW_OFST); + writel(low, systimer_base + TS_CMP_VAL_LW_OFST); +} + +static inline void rtk_cmp_en_write(bool cmp_en) +{ + u32 val; + + val = TS_WR_EN0_MASK; + if (cmp_en == ENBL) + val |= TS_CMP_EN_MASK; + + writel(val, systimer_base + TS_CMP_CTRL_OFST); +} + +static int rtk_syst_clkevt_next_event(unsigned long cycles, struct clock_event_device *clkevt) +{ + u64 cmp_val; + + rtk_cmp_en_write(DSBL); + cmp_val = rtk_ts64_read(); + + /* Set CMP value to current timestamp plus delta_us */ + rtk_cmp_value_write(cmp_val + cycles); + rtk_cmp_en_write(ENBL); + return 0; +} + +static irqreturn_t rtk_ts_match_intr_handler(int irq, void *dev_id) +{ + struct clock_event_device *clkevt = dev_id; + void __iomem *reg_base; + u32 val; + + /* Disable TS CMP Match */ + rtk_cmp_en_write(DSBL); + + /* Clear TS CMP INTR */ + reg_base = systimer_base + TS_CMP_STAT_OFST; + val = readl(reg_base) & TS_CMP_EN_MASK; + writel(val | TS_CMP_EN_MASK, reg_base); + clkevt->event_handler(clkevt); + + return IRQ_HANDLED; +} + +static int rtk_syst_shutdown(struct clock_event_device *clkevt) +{ + void __iomem *reg_base; + u64 cmp_val = 0; + + /* Disable TS CMP Match */ + rtk_cmp_en_write(DSBL); + /* Set compare value to 0 */ + rtk_cmp_value_write(cmp_val); + + /* Clear TS CMP INTR */ + reg_base = systimer_base + TS_CMP_STAT_OFST; + writel(TS_CMP_EN_MASK, reg_base); + return 0; +} + +static struct timer_of rtk_timer_to = { + .flags = TIMER_OF_IRQ | TIMER_OF_BASE, + + .clkevt = { + .name = "rtk-clkevt", + .rating = 300, + .cpumask = cpu_possible_mask, + .features = CLOCK_EVT_FEAT_DYNIRQ | + CLOCK_EVT_FEAT_ONESHOT, + .set_next_event = rtk_syst_clkevt_next_event, + .set_state_oneshot = rtk_syst_shutdown, + .set_state_shutdown = rtk_syst_shutdown, + }, + + .of_irq = { + .flags = IRQF_TIMER | IRQF_IRQPOLL, + .handler = rtk_ts_match_intr_handler, + }, +}; + +static int __init rtk_systimer_init(struct device_node *node) +{ + int ret; + + ret = timer_of_init(node, &rtk_timer_to); + if (ret) + return ret; + + systimer_base = timer_of_base(&rtk_timer_to); + clockevents_config_and_register(&rtk_timer_to.clkevt, SYSTIMER_RATE, + SYSTIMER_MIN_DELTA, SYSTIMER_MAX_DELTA); + + return 0; +} + +TIMER_OF_DECLARE(rtk_systimer, "realtek,rtd1625-systimer", rtk_systimer_init);