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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-23 13:28:57 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-23 13:28:57 -0700 |
| commit | 4352b8aee98005853aa63f57d6377282de17a33f (patch) | |
| tree | 27614d7a9ef05c32d089004e104364ce42324837 /drivers/clocksource/timer-riscv.c | |
| download | linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.tar.gz linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.zip | |
Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted
Pull I3C updates from Alexandre Belloni:
"A new driver this cycle, for the AMD AXI I3C controller.
There are also new features such as IBI wakeup support, SETAASA device
discovery and ACPI support for the the DAA methods, meaning we can now
communicate with the SPD devices on DDR5 modules.
New driver:
- AMD AXI I3C master controller
Subsystem:
- I3C Common Command Code (CCC) handling improvements, especially
around GET CCCs
- SETAASA device discovery support
- ACPI support for all existing DAA methods like SETDASA, SETNEWDA as
well as I2C devices on I3C bus
- IBI-based wakeup support
Drivers:
- dw: SETAASA support
- mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C
controller support, PIO queue management support for HCI v1.2
- renesas: improve suspend to RAM support, add runtime PM support"
* tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits)
i3c: dw: reduce do_daa time if there's no client
i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller
i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2
i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode
i3c: dw: rename "pclk" to "apb" to match dt-binding
i3c: dw: make struct dw_i3c_cmd smaller
i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding
i3c: renesas: Don't register devices when ENTDAA times out
i3c: master: dw-i3c-master: fix OD timing for first broadcast
i3c: mipi-i3c-hci: Advertise IBI wakeup capability
i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
i3c: master: Reject IBI requests from non-IBI-capable devices
i3c: master: Add helper to query bus wakeup requirements
i3c: master: Report wakeup events for IBIs
i3c: master: Support IBI-based wakeup capability
i3c: master: Fix potential UAF in i3c_device_match()
i3c: master: Fix potential UAF in i3c_device_uevent()
i3c: Make dev->desc locking assumptions explicit
i3c: master: Fix use-after-free of master->this
...
Diffstat (limited to 'drivers/clocksource/timer-riscv.c')
| -rw-r--r-- | drivers/clocksource/timer-riscv.c | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/drivers/clocksource/timer-riscv.c b/drivers/clocksource/timer-riscv.c new file mode 100644 index 000000000..b310e6721 --- /dev/null +++ b/drivers/clocksource/timer-riscv.c @@ -0,0 +1,250 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2012 Regents of the University of California + * Copyright (C) 2017 SiFive + * + * All RISC-V systems have a timer attached to every hart. These timers can + * either be read from the "time" and "timeh" CSRs, and can use the SBI to + * setup events, or directly accessed using MMIO registers. + */ + +#define pr_fmt(fmt) "riscv-timer: " fmt + +#include <linux/acpi.h> +#include <linux/clocksource.h> +#include <linux/clockchips.h> +#include <linux/cpu.h> +#include <linux/delay.h> +#include <linux/irq.h> +#include <linux/irqdomain.h> +#include <linux/module.h> +#include <linux/sched_clock.h> +#include <linux/io-64-nonatomic-lo-hi.h> +#include <linux/interrupt.h> +#include <linux/of_irq.h> +#include <linux/limits.h> +#include <clocksource/timer-riscv.h> +#include <asm/smp.h> +#include <asm/cpufeature.h> +#include <asm/sbi.h> +#include <asm/timex.h> + +static DEFINE_STATIC_KEY_FALSE(riscv_sstc_available); +static bool riscv_timer_cannot_wake_cpu; + +static void riscv_clock_event_stop(void) +{ + if (static_branch_likely(&riscv_sstc_available)) { + csr_write(CSR_STIMECMP, ULONG_MAX); + if (IS_ENABLED(CONFIG_32BIT)) + csr_write(CSR_STIMECMPH, ULONG_MAX); + } else { + sbi_set_timer(U64_MAX); + } +} + +static int riscv_clock_next_event(unsigned long delta, + struct clock_event_device *ce) +{ + u64 next_tval = get_cycles64() + delta; + + if (static_branch_likely(&riscv_sstc_available)) { +#if defined(CONFIG_32BIT) + csr_write(CSR_STIMECMP, ULONG_MAX); + csr_write(CSR_STIMECMPH, next_tval >> 32); + csr_write(CSR_STIMECMP, next_tval & 0xFFFFFFFF); +#else + csr_write(CSR_STIMECMP, next_tval); +#endif + } else + sbi_set_timer(next_tval); + + return 0; +} + +static int riscv_clock_shutdown(struct clock_event_device *evt) +{ + riscv_clock_event_stop(); + return 0; +} + +static unsigned int riscv_clock_event_irq; +static DEFINE_PER_CPU(struct clock_event_device, riscv_clock_event) = { + .name = "riscv_timer_clockevent", + .features = CLOCK_EVT_FEAT_ONESHOT, + .rating = 100, + .set_next_event = riscv_clock_next_event, + .set_state_shutdown = riscv_clock_shutdown, +}; + +/* + * It is guaranteed that all the timers across all the harts are synchronized + * within one tick of each other, so while this could technically go + * backwards when hopping between CPUs, practically it won't happen. + */ +static unsigned long long riscv_clocksource_rdtime(struct clocksource *cs) +{ + return get_cycles64(); +} + +static u64 notrace riscv_sched_clock(void) +{ + return get_cycles64(); +} + +static struct clocksource riscv_clocksource = { + .name = "riscv_clocksource", + .rating = 400, + .mask = CLOCKSOURCE_MASK(64), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, + .read = riscv_clocksource_rdtime, + .vdso_clock_mode = VDSO_CLOCKMODE_ARCHTIMER, +}; + +static int riscv_timer_starting_cpu(unsigned int cpu) +{ + struct clock_event_device *ce = per_cpu_ptr(&riscv_clock_event, cpu); + + /* Clear timer interrupt */ + riscv_clock_event_stop(); + + ce->cpumask = cpumask_of(cpu); + ce->irq = riscv_clock_event_irq; + if (riscv_timer_cannot_wake_cpu) + ce->features |= CLOCK_EVT_FEAT_C3STOP; + if (static_branch_likely(&riscv_sstc_available)) + ce->rating = 450; + clockevents_config_and_register(ce, riscv_timebase, 100, ULONG_MAX); + + enable_percpu_irq(riscv_clock_event_irq, + irq_get_trigger_type(riscv_clock_event_irq)); + return 0; +} + +static int riscv_timer_dying_cpu(unsigned int cpu) +{ + /* + * Stop the timer when the cpu is going to be offline otherwise + * the timer interrupt may be pending while performing power-down. + */ + riscv_clock_event_stop(); + disable_percpu_irq(riscv_clock_event_irq); + + return 0; +} + +void riscv_cs_get_mult_shift(u32 *mult, u32 *shift) +{ + *mult = riscv_clocksource.mult; + *shift = riscv_clocksource.shift; +} +EXPORT_SYMBOL_GPL(riscv_cs_get_mult_shift); + +/* called directly from the low-level interrupt handler */ +static irqreturn_t riscv_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evdev = this_cpu_ptr(&riscv_clock_event); + + riscv_clock_event_stop(); + evdev->event_handler(evdev); + + return IRQ_HANDLED; +} + +static int __init riscv_timer_init_common(void) +{ + int error; + struct irq_domain *domain; + struct fwnode_handle *intc_fwnode = riscv_get_intc_hwnode(); + + domain = irq_find_matching_fwnode(intc_fwnode, DOMAIN_BUS_ANY); + if (!domain) { + pr_err("Failed to find irq_domain for INTC node [%pfwP]\n", + intc_fwnode); + return -ENODEV; + } + + riscv_clock_event_irq = irq_create_mapping(domain, RV_IRQ_TIMER); + if (!riscv_clock_event_irq) { + pr_err("Failed to map timer interrupt for node [%pfwP]\n", intc_fwnode); + return -ENODEV; + } + + error = clocksource_register_hz(&riscv_clocksource, riscv_timebase); + if (error) { + pr_err("RISCV timer registration failed [%d]\n", error); + return error; + } + + sched_clock_register(riscv_sched_clock, 64, riscv_timebase); + + error = request_percpu_irq(riscv_clock_event_irq, + riscv_timer_interrupt, + "riscv-timer", &riscv_clock_event); + if (error) { + pr_err("registering percpu irq failed [%d]\n", error); + return error; + } + + if (riscv_isa_extension_available(NULL, SSTC)) { + pr_info("Timer interrupt in S-mode is available via sstc extension\n"); + static_branch_enable(&riscv_sstc_available); + } + + error = cpuhp_setup_state(CPUHP_AP_RISCV_TIMER_STARTING, + "clockevents/riscv/timer:starting", + riscv_timer_starting_cpu, riscv_timer_dying_cpu); + if (error) + pr_err("cpu hp setup state failed for RISCV timer [%d]\n", + error); + + return error; +} + +static int __init riscv_timer_init_dt(struct device_node *n) +{ + int cpuid, error; + unsigned long hartid; + struct device_node *child; + + error = riscv_of_processor_hartid(n, &hartid); + if (error < 0) { + pr_warn("Invalid hartid for node [%pOF] error = [%lu]\n", + n, hartid); + return error; + } + + cpuid = riscv_hartid_to_cpuid(hartid); + if (cpuid < 0) { + pr_warn("Invalid cpuid for hartid [%lu]\n", hartid); + return cpuid; + } + + if (cpuid != smp_processor_id()) + return 0; + + child = of_find_compatible_node(NULL, NULL, "riscv,timer"); + if (child) { + riscv_timer_cannot_wake_cpu = of_property_read_bool(child, + "riscv,timer-cannot-wake-cpu"); + of_node_put(child); + } + + return riscv_timer_init_common(); +} + +TIMER_OF_DECLARE(riscv_timer, "riscv", riscv_timer_init_dt); + +#ifdef CONFIG_ACPI +static int __init riscv_timer_acpi_init(struct acpi_table_header *table) +{ + struct acpi_table_rhct *rhct = (struct acpi_table_rhct *)table; + + riscv_timer_cannot_wake_cpu = rhct->flags & ACPI_RHCT_TIMER_CANNOT_WAKEUP_CPU; + + return riscv_timer_init_common(); +} + +TIMER_ACPI_DECLARE(aclint_mtimer, ACPI_SIG_RHCT, riscv_timer_acpi_init); + +#endif |
