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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-ep93xx.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-ep93xx.c')
| -rw-r--r-- | drivers/clocksource/timer-ep93xx.c | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/drivers/clocksource/timer-ep93xx.c b/drivers/clocksource/timer-ep93xx.c new file mode 100644 index 000000000..1b719282c --- /dev/null +++ b/drivers/clocksource/timer-ep93xx.c @@ -0,0 +1,189 @@ +// 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> + +/************************************************************************* + * 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; + +static u64 ep93xx_clocksource_read(struct clocksource *c) +{ + 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_obj(*tcu); + 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) { + ret = -EINVAL; + 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); + 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); + + 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); |
