From 034dd340b08be1f2f0477ad16131d609f9dbd53c Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 30 Aug 2026 09:22:00 -0700 Subject: Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Fix error output of boot instance creation failure Currently if a boot instance creation fails, instead of printing out the name of the instance that failed, it prints "(null)". That is because it prints "cur_str" that had already been processed by strsep(). Print the saved name instead. While at it, print the error code of the failure. - Fix use-after-free for same named historgrams Histograms can be named so that they can be used in multiple events. But if the named histogram has a variable attached, the second event that uses the named histogram which duplicates it and needs to free the original after duplication leaves the old variable in place and still visible. If another histogram uses than variable, it will use the stale one which will try to reference the freed duplicate histogram and crash the kernel. Free the duplicate variables along with the duplicated histogram data. - Check return value of kthread_run() in event self test The events self tests uses a kthread for testing but does not check if it succeeded in creating a kthread. If the kthread creation were to fail, the code will still try to call kthread_stop() on the error returned. - Fix race between reading trace_pipe and updating subbuffer size If a user is reading the trace_pipe file at the same time they update the ring buffer sub-buffer size, can cause the trace_pipe read to read stale data. Add trace_access_lock() around updating the ring buffer sub-buffer size. - Fix eventfs_inode on failure path in creation of the events directory In the creation of the "events" directory, if after allocating the eventfs_inode a failure is detected, it calls cleanup_ei() which calls free_ei(). The free_ei() will test if eventfs_inode being freed has no children. It is a bug if it does. But on the failure case of the creation of the "events" directory, the children lists have not yet been initialized and the free will trigger a warning because list_empty() on an uninitialized list returns false. Move the initialization into init_ei() where it makes more sense and makes sure that a created eventfs_inode has its lists initialized upon creation. - Check return value of kthread_run() in ftrace direct sample code The sample code that shows how to use the ftrace direct calls does not test the return of kthread_run() to see if it succeeds. Return a failure if the kthread_run() doesn't succeed. - Clear user events state on fork in case of alloc failure On fork, the child gets a pointer to the parent's user events state. It makes a copy of it then updates the child's pointer to it. But if the allocation fails, the duplication function leaves the child with a pointer to its parent's descriptor. When the child cleans up its data, it will free the parent's descriptor while the parent is still using it. In the duplication function, set the child's user_event_mm to NULL before testing if the allocation succeeded, and when it exits it will not free the parent's descriptor. - Fix retry exhaustion in simple ring buffer reader swap simple_ring_buffer_swap_reader_page() starts with retry set to 8 and post-decrements it only after a failed link replacement. On the final attempt, a successful replacement leaves retry at zero, while a failed replacement leaves it at -1. But the check for success expects the retry value to be non-zero and exits with an error on zero. This is the opposite result. Fix it. - Fail nicely when the remote swap_reader_page() returns an error Currently, if the swap_reader_page() of a remote buffer fails, it triggers a WARN_ON_ONCE() and continues normally. Instead, have it exit with an error and a pr_warn() print instead of a full WARNING. * tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ring-buffer: Stop remote reader update when page swap fails tracing: Fix retry exhaustion in simple ring buffer reader swap tracing/user_events: Clear copied tracing state before fork duplication samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify eventfs: Initialize ei->children and ei->list in init_ei() tracing: Fix use-after-free in trace_pipe read on sub-buffer order change tracing: Fix crash passing ERR_PTR to kthread_stop() tracing: Fix use-after-free with same-name named triggers tracing: Fix logged instance name on creation failure --- drivers/clocksource/timer-nxp-stm.c | 496 ++++++++++++++++++++++++++++++++++++ 1 file changed, 496 insertions(+) create mode 100644 drivers/clocksource/timer-nxp-stm.c (limited to 'drivers/clocksource/timer-nxp-stm.c') diff --git a/drivers/clocksource/timer-nxp-stm.c b/drivers/clocksource/timer-nxp-stm.c new file mode 100644 index 000000000..6fe098a4a --- /dev/null +++ b/drivers/clocksource/timer-nxp-stm.c @@ -0,0 +1,496 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright 2016 Freescale Semiconductor, Inc. + * Copyright 2018,2021-2025 NXP + * + * NXP System Timer Module: + * + * STM supports commonly required system and application software + * timing functions. STM includes a 32-bit count-up timer and four + * 32-bit compare channels with a separate interrupt source for each + * channel. The timer is driven by the STM module clock divided by an + * 8-bit prescale value (1 to 256). It has ability to stop the timer + * in Debug mode + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define STM_CR(__base) (__base) + +#define STM_CR_TEN BIT(0) +#define STM_CR_FRZ BIT(1) +#define STM_CR_CPS_OFFSET 8u +#define STM_CR_CPS_MASK GENMASK(15, STM_CR_CPS_OFFSET) + +#define STM_CNT(__base) ((__base) + 0x04) + +#define STM_CCR0(__base) ((__base) + 0x10) +#define STM_CCR1(__base) ((__base) + 0x20) +#define STM_CCR2(__base) ((__base) + 0x30) +#define STM_CCR3(__base) ((__base) + 0x40) + +#define STM_CCR_CEN BIT(0) + +#define STM_CIR0(__base) ((__base) + 0x14) +#define STM_CIR1(__base) ((__base) + 0x24) +#define STM_CIR2(__base) ((__base) + 0x34) +#define STM_CIR3(__base) ((__base) + 0x44) + +#define STM_CIR_CIF BIT(0) + +#define STM_CMP0(__base) ((__base) + 0x18) +#define STM_CMP1(__base) ((__base) + 0x28) +#define STM_CMP2(__base) ((__base) + 0x38) +#define STM_CMP3(__base) ((__base) + 0x48) + +#define STM_ENABLE_MASK (STM_CR_FRZ | STM_CR_TEN) + +struct stm_timer { + void __iomem *base; + unsigned long rate; + unsigned long delta; + unsigned long counter; + struct clock_event_device ced; + struct clocksource cs; + atomic_t refcnt; +}; + +static DEFINE_PER_CPU(struct stm_timer *, stm_timers); + +static struct stm_timer *stm_sched_clock; + +/* + * Global structure for multiple STMs initialization + */ +static int stm_instances; + +/* + * This global lock is used to prevent race conditions with the + * stm_instances in case the driver is using the ASYNC option + */ +static DEFINE_MUTEX(stm_instances_lock); + +DEFINE_GUARD(stm_instances, struct mutex *, mutex_lock(_T), mutex_unlock(_T)) + +static struct stm_timer *cs_to_stm(struct clocksource *cs) +{ + return container_of(cs, struct stm_timer, cs); +} + +static struct stm_timer *ced_to_stm(struct clock_event_device *ced) +{ + return container_of(ced, struct stm_timer, ced); +} + +static u64 notrace nxp_stm_read_sched_clock(void) +{ + return readl(STM_CNT(stm_sched_clock->base)); +} + +static u32 nxp_stm_clocksource_getcnt(struct stm_timer *stm_timer) +{ + return readl(STM_CNT(stm_timer->base)); +} + +static void nxp_stm_clocksource_setcnt(struct stm_timer *stm_timer, u32 cnt) +{ + writel(cnt, STM_CNT(stm_timer->base)); +} + +static u64 nxp_stm_clocksource_read(struct clocksource *cs) +{ + struct stm_timer *stm_timer = cs_to_stm(cs); + + return (u64)nxp_stm_clocksource_getcnt(stm_timer); +} + +static void nxp_stm_module_enable(struct stm_timer *stm_timer) +{ + u32 reg; + + reg = readl(STM_CR(stm_timer->base)); + + reg |= STM_ENABLE_MASK; + + writel(reg, STM_CR(stm_timer->base)); +} + +static void nxp_stm_module_disable(struct stm_timer *stm_timer) +{ + u32 reg; + + reg = readl(STM_CR(stm_timer->base)); + + reg &= ~STM_ENABLE_MASK; + + writel(reg, STM_CR(stm_timer->base)); +} + +static void nxp_stm_module_put(struct stm_timer *stm_timer) +{ + if (atomic_dec_and_test(&stm_timer->refcnt)) + nxp_stm_module_disable(stm_timer); +} + +static void nxp_stm_module_get(struct stm_timer *stm_timer) +{ + if (atomic_inc_return(&stm_timer->refcnt) == 1) + nxp_stm_module_enable(stm_timer); +} + +static int nxp_stm_clocksource_enable(struct clocksource *cs) +{ + struct stm_timer *stm_timer = cs_to_stm(cs); + + nxp_stm_module_get(stm_timer); + + return 0; +} + +static void nxp_stm_clocksource_disable(struct clocksource *cs) +{ + struct stm_timer *stm_timer = cs_to_stm(cs); + + nxp_stm_module_put(stm_timer); +} + +static void nxp_stm_clocksource_suspend(struct clocksource *cs) +{ + struct stm_timer *stm_timer = cs_to_stm(cs); + + nxp_stm_clocksource_disable(cs); + stm_timer->counter = nxp_stm_clocksource_getcnt(stm_timer); +} + +static void nxp_stm_clocksource_resume(struct clocksource *cs) +{ + struct stm_timer *stm_timer = cs_to_stm(cs); + + nxp_stm_clocksource_setcnt(stm_timer, stm_timer->counter); + nxp_stm_clocksource_enable(cs); +} + +static void devm_clocksource_unregister(void *data) +{ + struct stm_timer *stm_timer = data; + + clocksource_unregister(&stm_timer->cs); +} + +static int nxp_stm_clocksource_init(struct device *dev, struct stm_timer *stm_timer, + const char *name, void __iomem *base, struct clk *clk) +{ + int ret; + + stm_timer->base = base; + stm_timer->rate = clk_get_rate(clk); + + stm_timer->cs.name = name; + stm_timer->cs.rating = 460; + stm_timer->cs.read = nxp_stm_clocksource_read; + stm_timer->cs.enable = nxp_stm_clocksource_enable; + stm_timer->cs.disable = nxp_stm_clocksource_disable; + stm_timer->cs.suspend = nxp_stm_clocksource_suspend; + stm_timer->cs.resume = nxp_stm_clocksource_resume; + stm_timer->cs.mask = CLOCKSOURCE_MASK(32); + stm_timer->cs.flags = CLOCK_SOURCE_IS_CONTINUOUS; + stm_timer->cs.owner = THIS_MODULE; + + ret = clocksource_register_hz(&stm_timer->cs, stm_timer->rate); + if (ret) + return ret; + + ret = devm_add_action_or_reset(dev, devm_clocksource_unregister, stm_timer); + if (ret) + return ret; + + stm_sched_clock = stm_timer; + + sched_clock_register(nxp_stm_read_sched_clock, 32, stm_timer->rate); + + dev_dbg(dev, "Registered clocksource %s\n", name); + + return 0; +} + +static int nxp_stm_clockevent_read_counter(struct stm_timer *stm_timer) +{ + return readl(STM_CNT(stm_timer->base)); +} + +static void nxp_stm_clockevent_disable(struct stm_timer *stm_timer) +{ + writel(0, STM_CCR0(stm_timer->base)); +} + +static void nxp_stm_clockevent_enable(struct stm_timer *stm_timer) +{ + writel(STM_CCR_CEN, STM_CCR0(stm_timer->base)); +} + +static int nxp_stm_clockevent_shutdown(struct clock_event_device *ced) +{ + struct stm_timer *stm_timer = ced_to_stm(ced); + + nxp_stm_clockevent_disable(stm_timer); + + return 0; +} + +static int nxp_stm_clockevent_set_next_event(unsigned long delta, struct clock_event_device *ced) +{ + struct stm_timer *stm_timer = ced_to_stm(ced); + u32 val; + + nxp_stm_clockevent_disable(stm_timer); + + stm_timer->delta = delta; + + val = nxp_stm_clockevent_read_counter(stm_timer) + delta; + + writel(val, STM_CMP0(stm_timer->base)); + + /* + * The counter is shared across the channels and can not be + * stopped while we are setting the next event. If the delta + * is very small it is possible the counter increases above + * the computed 'val'. The min_delta value specified when + * registering the clockevent will prevent that. The second + * case is if the counter wraps while we compute the 'val' and + * before writing the comparator register. We read the counter, + * check if we are back in time and abort the timer with -ETIME. + */ + if (val > nxp_stm_clockevent_read_counter(stm_timer) + delta) + return -ETIME; + + nxp_stm_clockevent_enable(stm_timer); + + return 0; +} + +static int nxp_stm_clockevent_set_periodic(struct clock_event_device *ced) +{ + struct stm_timer *stm_timer = ced_to_stm(ced); + + return nxp_stm_clockevent_set_next_event(stm_timer->rate, ced); +} + +static void nxp_stm_clockevent_suspend(struct clock_event_device *ced) +{ + struct stm_timer *stm_timer = ced_to_stm(ced); + + nxp_stm_module_put(stm_timer); +} + +static void nxp_stm_clockevent_resume(struct clock_event_device *ced) +{ + struct stm_timer *stm_timer = ced_to_stm(ced); + + nxp_stm_module_get(stm_timer); +} + +static int nxp_stm_clockevent_per_cpu_init(struct device *dev, struct stm_timer *stm_timer, + const char *name, void __iomem *base, int irq, + struct clk *clk, int cpu) +{ + stm_timer->base = base; + stm_timer->rate = clk_get_rate(clk); + + stm_timer->ced.name = name; + stm_timer->ced.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT; + stm_timer->ced.set_state_shutdown = nxp_stm_clockevent_shutdown; + stm_timer->ced.set_state_periodic = nxp_stm_clockevent_set_periodic; + stm_timer->ced.set_next_event = nxp_stm_clockevent_set_next_event; + stm_timer->ced.suspend = nxp_stm_clockevent_suspend; + stm_timer->ced.resume = nxp_stm_clockevent_resume; + stm_timer->ced.cpumask = cpumask_of(cpu); + stm_timer->ced.rating = 460; + stm_timer->ced.irq = irq; + stm_timer->ced.owner = THIS_MODULE; + + per_cpu(stm_timers, cpu) = stm_timer; + + nxp_stm_module_get(stm_timer); + + dev_dbg(dev, "Initialized per cpu clockevent name=%s, irq=%d, cpu=%d\n", name, irq, cpu); + + return 0; +} + +static int nxp_stm_clockevent_starting_cpu(unsigned int cpu) +{ + struct stm_timer *stm_timer = per_cpu(stm_timers, cpu); + int ret; + + if (WARN_ON(!stm_timer)) + return -EFAULT; + + ret = irq_force_affinity(stm_timer->ced.irq, cpumask_of(cpu)); + if (ret) + return ret; + + /* + * The timings measurement show reading the counter register + * and writing to the comparator register takes as a maximum + * value 1100 ns at 133MHz rate frequency. The timer must be + * set above this value and to be secure we set the minimum + * value equal to 2000ns, so 2us. + * + * minimum ticks = (rate / MICRO) * 2 + */ + clockevents_config_and_register(&stm_timer->ced, stm_timer->rate, + (stm_timer->rate / MICRO) * 2, ULONG_MAX); + + return 0; +} + +static irqreturn_t nxp_stm_module_interrupt(int irq, void *dev_id) +{ + struct stm_timer *stm_timer = dev_id; + struct clock_event_device *ced = &stm_timer->ced; + u32 val; + + /* + * The interrupt is shared across the channels in the + * module. But this one is configured to run only one channel, + * consequently it is pointless to test the interrupt flags + * before and we can directly reset the channel 0 irq flag + * register. + */ + writel(STM_CIR_CIF, STM_CIR0(stm_timer->base)); + + /* + * Update STM_CMP value using the counter value + */ + val = nxp_stm_clockevent_read_counter(stm_timer) + stm_timer->delta; + + writel(val, STM_CMP0(stm_timer->base)); + + /* + * stm hardware doesn't support oneshot, it will generate an + * interrupt and start the counter again so software needs to + * disable the timer to stop the counter loop in ONESHOT mode. + */ + if (likely(clockevent_state_oneshot(ced))) + nxp_stm_clockevent_disable(stm_timer); + + ced->event_handler(ced); + + return IRQ_HANDLED; +} + +static int nxp_stm_timer_probe(struct platform_device *pdev) +{ + struct stm_timer *stm_timer; + struct device *dev = &pdev->dev; + struct device_node *np = dev->of_node; + const char *name = of_node_full_name(np); + struct clk *clk; + void __iomem *base; + int irq, ret; + + /* + * The device tree can have multiple STM nodes described, so + * it makes this driver a good candidate for the async probe. + * It is still unclear if the time framework correctly handles + * parallel loading of the timers but at least this driver is + * ready to support the option. + */ + guard(stm_instances)(&stm_instances_lock); + + /* + * The S32Gx are SoCs featuring a diverse set of cores. Linux + * is expected to run on Cortex-A53 cores, while other + * software stacks will operate on Cortex-M cores. The number + * of STM instances has been sized to include at most one + * instance per core. + * + * As we need a clocksource and a clockevent per cpu, we + * simply initialize a clocksource per cpu along with the + * clockevent which makes the resulting code simpler. + * + * However if the device tree is describing more STM instances + * than the number of cores, then we ignore them. + */ + if (stm_instances >= num_possible_cpus()) + return 0; + + base = devm_of_iomap(dev, np, 0, NULL); + if (IS_ERR(base)) + return dev_err_probe(dev, PTR_ERR(base), "Failed to iomap %pOFn\n", np); + + irq = platform_get_irq(pdev, 0); + if (irq < 0) + return dev_err_probe(dev, irq, "Failed to get IRQ\n"); + + clk = devm_clk_get_enabled(dev, NULL); + if (IS_ERR(clk)) + return dev_err_probe(dev, PTR_ERR(clk), "Clock not found\n"); + + stm_timer = devm_kzalloc(dev, sizeof(*stm_timer), GFP_KERNEL); + if (!stm_timer) + return -ENOMEM; + + ret = devm_request_irq(dev, irq, nxp_stm_module_interrupt, + IRQF_TIMER | IRQF_NOBALANCING, name, stm_timer); + if (ret) + return ret; + + ret = nxp_stm_clocksource_init(dev, stm_timer, name, base, clk); + if (ret) + return ret; + + /* + * Next probed STM will be a per CPU clockevent, until we + * probe as many as we have CPUs available on the system, we + * do a partial initialization + */ + ret = nxp_stm_clockevent_per_cpu_init(dev, stm_timer, name, + base, irq, clk, + stm_instances); + if (ret) + return ret; + + stm_instances++; + + /* + * The number of probed STMs for per CPU clockevent is + * equal to the number of available CPUs on the + * system. We install the cpu hotplug to finish the + * initialization by registering the clockevents + */ + if (stm_instances == num_possible_cpus()) { + ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "STM timer:starting", + nxp_stm_clockevent_starting_cpu, NULL); + if (ret < 0) + return ret; + } + + return 0; +} + +static const struct of_device_id nxp_stm_of_match[] = { + { .compatible = "nxp,s32g2-stm" }, + { } +}; +MODULE_DEVICE_TABLE(of, nxp_stm_of_match); + +static struct platform_driver nxp_stm_driver = { + .probe = nxp_stm_timer_probe, + .driver = { + .name = "nxp-stm", + .of_match_table = nxp_stm_of_match, + .suppress_bind_attrs = true, + }, +}; +builtin_platform_driver(nxp_stm_driver); + +MODULE_DESCRIPTION("NXP System Timer Module driver"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1