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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-cadence-ttc.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-cadence-ttc.c')
| -rw-r--r-- | drivers/clocksource/timer-cadence-ttc.c | 565 |
1 files changed, 565 insertions, 0 deletions
diff --git a/drivers/clocksource/timer-cadence-ttc.c b/drivers/clocksource/timer-cadence-ttc.c new file mode 100644 index 000000000..3c50d6892 --- /dev/null +++ b/drivers/clocksource/timer-cadence-ttc.c @@ -0,0 +1,565 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * This file contains driver for the Cadence Triple Timer Counter Rev 06 + * + * Copyright (C) 2011-2013 Xilinx + * + * based on arch/mips/kernel/time.c timer driver + */ + +#include <linux/clk.h> +#include <linux/interrupt.h> +#include <linux/clockchips.h> +#include <linux/clocksource.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/sched_clock.h> +#include <linux/module.h> +#include <linux/of_platform.h> + +/* + * This driver configures the 2 16/32-bit count-up timers as follows: + * + * T1: Timer 1, clocksource for generic timekeeping + * T2: Timer 2, clockevent source for hrtimers + * T3: Timer 3, <unused> + * + * The input frequency to the timer module for emulation is 2.5MHz which is + * common to all the timer channels (T1, T2, and T3). With a pre-scaler of 32, + * the timers are clocked at 78.125KHz (12.8 us resolution). + + * The input frequency to the timer module in silicon is configurable and + * obtained from device tree. The pre-scaler of 32 is used. + */ + +/* + * Timer Register Offset Definitions of Timer 1, Increment base address by 4 + * and use same offsets for Timer 2 + */ +#define TTC_CLK_CNTRL_OFFSET 0x00 /* Clock Control Reg, RW */ +#define TTC_CNT_CNTRL_OFFSET 0x0C /* Counter Control Reg, RW */ +#define TTC_COUNT_VAL_OFFSET 0x18 /* Counter Value Reg, RO */ +#define TTC_INTR_VAL_OFFSET 0x24 /* Interval Count Reg, RW */ +#define TTC_ISR_OFFSET 0x54 /* Interrupt Status Reg, RO */ +#define TTC_IER_OFFSET 0x60 /* Interrupt Enable Reg, RW */ + +#define TTC_CNT_CNTRL_DISABLE_MASK 0x1 + +#define TTC_CLK_CNTRL_CSRC_MASK (1 << 5) /* clock source */ +#define TTC_CLK_CNTRL_PSV_MASK 0x1e +#define TTC_CLK_CNTRL_PSV_SHIFT 1 + +/* + * Setup the timers to use pre-scaling, using a fixed value for now that will + * work across most input frequency, but it may need to be more dynamic + */ +#define PRESCALE_EXPONENT 11 /* 2 ^ PRESCALE_EXPONENT = PRESCALE */ +#define PRESCALE 2048 /* The exponent must match this */ +#define CLK_CNTRL_PRESCALE ((PRESCALE_EXPONENT - 1) << 1) +#define CLK_CNTRL_PRESCALE_EN 1 +#define CNT_CNTRL_RESET (1 << 4) + +#define MAX_F_ERR 50 + +/** + * struct ttc_timer - This definition defines local timer structure + * + * @base_addr: Base address of timer + * @freq: Timer input clock frequency + * @clk: Associated clock source + * @clk_rate_change_nb: Notifier block for clock rate changes + */ +struct ttc_timer { + void __iomem *base_addr; + unsigned long freq; + struct clk *clk; + struct notifier_block clk_rate_change_nb; +}; + +#define to_ttc_timer(x) \ + container_of(x, struct ttc_timer, clk_rate_change_nb) + +struct ttc_timer_clocksource { + u32 scale_clk_ctrl_reg_old; + u32 scale_clk_ctrl_reg_new; + struct ttc_timer ttc; + struct clocksource cs; +}; + +#define to_ttc_timer_clksrc(x) \ + container_of(x, struct ttc_timer_clocksource, cs) + +struct ttc_timer_clockevent { + struct ttc_timer ttc; + struct clock_event_device ce; +}; + +#define to_ttc_timer_clkevent(x) \ + container_of(x, struct ttc_timer_clockevent, ce) + +static void __iomem *ttc_sched_clock_val_reg; + +/** + * ttc_set_interval - Set the timer interval value + * + * @timer: Pointer to the timer instance + * @cycles: Timer interval ticks + **/ +static void ttc_set_interval(struct ttc_timer *timer, + unsigned long cycles) +{ + u32 ctrl_reg; + + /* Disable the counter, set the counter value and re-enable counter */ + ctrl_reg = readl_relaxed(timer->base_addr + TTC_CNT_CNTRL_OFFSET); + ctrl_reg |= TTC_CNT_CNTRL_DISABLE_MASK; + writel_relaxed(ctrl_reg, timer->base_addr + TTC_CNT_CNTRL_OFFSET); + + writel_relaxed(cycles, timer->base_addr + TTC_INTR_VAL_OFFSET); + + /* + * Reset the counter (0x10) so that it starts from 0, one-shot + * mode makes this needed for timing to be right. + */ + ctrl_reg |= CNT_CNTRL_RESET; + ctrl_reg &= ~TTC_CNT_CNTRL_DISABLE_MASK; + writel_relaxed(ctrl_reg, timer->base_addr + TTC_CNT_CNTRL_OFFSET); +} + +/** + * ttc_clock_event_interrupt - Clock event timer interrupt handler + * + * @irq: IRQ number of the Timer + * @dev_id: void pointer to the ttc_timer instance + * + * Returns: Always IRQ_HANDLED - success + **/ +static irqreturn_t ttc_clock_event_interrupt(int irq, void *dev_id) +{ + struct ttc_timer_clockevent *ttce = dev_id; + struct ttc_timer *timer = &ttce->ttc; + + /* Acknowledge the interrupt and call event handler */ + readl_relaxed(timer->base_addr + TTC_ISR_OFFSET); + + ttce->ce.event_handler(&ttce->ce); + + return IRQ_HANDLED; +} + +/** + * __ttc_clocksource_read - Reads the timer counter register + * @cs: &clocksource to read from + * + * Returns: Current timer counter register value + **/ +static u64 __ttc_clocksource_read(struct clocksource *cs) +{ + struct ttc_timer *timer = &to_ttc_timer_clksrc(cs)->ttc; + + return (u64)readl_relaxed(timer->base_addr + + TTC_COUNT_VAL_OFFSET); +} + +static u64 notrace ttc_sched_clock_read(void) +{ + return readl_relaxed(ttc_sched_clock_val_reg); +} + +/** + * ttc_set_next_event - Sets the time interval for next event + * + * @cycles: Timer interval ticks + * @evt: Address of clock event instance + * + * Returns: Always %0 - success + **/ +static int ttc_set_next_event(unsigned long cycles, + struct clock_event_device *evt) +{ + struct ttc_timer_clockevent *ttce = to_ttc_timer_clkevent(evt); + struct ttc_timer *timer = &ttce->ttc; + + ttc_set_interval(timer, cycles); + return 0; +} + +/** + * ttc_shutdown - Sets the state of timer + * @evt: Address of clock event instance + * + * Used for shutdown or oneshot. + * + * Returns: Always %0 - success + **/ +static int ttc_shutdown(struct clock_event_device *evt) +{ + struct ttc_timer_clockevent *ttce = to_ttc_timer_clkevent(evt); + struct ttc_timer *timer = &ttce->ttc; + u32 ctrl_reg; + + ctrl_reg = readl_relaxed(timer->base_addr + TTC_CNT_CNTRL_OFFSET); + ctrl_reg |= TTC_CNT_CNTRL_DISABLE_MASK; + writel_relaxed(ctrl_reg, timer->base_addr + TTC_CNT_CNTRL_OFFSET); + return 0; +} + +/** + * ttc_set_periodic - Sets the state of timer + * @evt: Address of clock event instance + * + * Returns: Always %0 - success + */ +static int ttc_set_periodic(struct clock_event_device *evt) +{ + struct ttc_timer_clockevent *ttce = to_ttc_timer_clkevent(evt); + struct ttc_timer *timer = &ttce->ttc; + + ttc_set_interval(timer, + DIV_ROUND_CLOSEST(ttce->ttc.freq, PRESCALE * HZ)); + return 0; +} + +static int ttc_resume(struct clock_event_device *evt) +{ + struct ttc_timer_clockevent *ttce = to_ttc_timer_clkevent(evt); + struct ttc_timer *timer = &ttce->ttc; + u32 ctrl_reg; + + ctrl_reg = readl_relaxed(timer->base_addr + TTC_CNT_CNTRL_OFFSET); + ctrl_reg &= ~TTC_CNT_CNTRL_DISABLE_MASK; + writel_relaxed(ctrl_reg, timer->base_addr + TTC_CNT_CNTRL_OFFSET); + return 0; +} + +static int ttc_rate_change_clocksource_cb(struct notifier_block *nb, + unsigned long event, void *data) +{ + struct clk_notifier_data *ndata = data; + struct ttc_timer *ttc = to_ttc_timer(nb); + struct ttc_timer_clocksource *ttccs = container_of(ttc, + struct ttc_timer_clocksource, ttc); + + switch (event) { + case PRE_RATE_CHANGE: + { + u32 psv; + unsigned long factor, rate_low, rate_high; + + if (ndata->new_rate > ndata->old_rate) { + factor = DIV_ROUND_CLOSEST(ndata->new_rate, + ndata->old_rate); + rate_low = ndata->old_rate; + rate_high = ndata->new_rate; + } else { + factor = DIV_ROUND_CLOSEST(ndata->old_rate, + ndata->new_rate); + rate_low = ndata->new_rate; + rate_high = ndata->old_rate; + } + + if (!is_power_of_2(factor)) + return NOTIFY_BAD; + + if (abs(rate_high - (factor * rate_low)) > MAX_F_ERR) + return NOTIFY_BAD; + + factor = __ilog2_u32(factor); + + /* + * store timer clock ctrl register so we can restore it in case + * of an abort. + */ + ttccs->scale_clk_ctrl_reg_old = + readl_relaxed(ttccs->ttc.base_addr + + TTC_CLK_CNTRL_OFFSET); + + psv = (ttccs->scale_clk_ctrl_reg_old & + TTC_CLK_CNTRL_PSV_MASK) >> + TTC_CLK_CNTRL_PSV_SHIFT; + if (ndata->new_rate < ndata->old_rate) + psv -= factor; + else + psv += factor; + + /* prescaler within legal range? */ + if (psv & ~(TTC_CLK_CNTRL_PSV_MASK >> TTC_CLK_CNTRL_PSV_SHIFT)) + return NOTIFY_BAD; + + ttccs->scale_clk_ctrl_reg_new = ttccs->scale_clk_ctrl_reg_old & + ~TTC_CLK_CNTRL_PSV_MASK; + ttccs->scale_clk_ctrl_reg_new |= psv << TTC_CLK_CNTRL_PSV_SHIFT; + + + /* scale down: adjust divider in post-change notification */ + if (ndata->new_rate < ndata->old_rate) + return NOTIFY_DONE; + + /* scale up: adjust divider now - before frequency change */ + writel_relaxed(ttccs->scale_clk_ctrl_reg_new, + ttccs->ttc.base_addr + TTC_CLK_CNTRL_OFFSET); + break; + } + case POST_RATE_CHANGE: + /* scale up: pre-change notification did the adjustment */ + if (ndata->new_rate > ndata->old_rate) + return NOTIFY_OK; + + /* scale down: adjust divider now - after frequency change */ + writel_relaxed(ttccs->scale_clk_ctrl_reg_new, + ttccs->ttc.base_addr + TTC_CLK_CNTRL_OFFSET); + break; + + case ABORT_RATE_CHANGE: + /* we have to undo the adjustment in case we scale up */ + if (ndata->new_rate < ndata->old_rate) + return NOTIFY_OK; + + /* restore original register value */ + writel_relaxed(ttccs->scale_clk_ctrl_reg_old, + ttccs->ttc.base_addr + TTC_CLK_CNTRL_OFFSET); + fallthrough; + default: + return NOTIFY_DONE; + } + + return NOTIFY_DONE; +} + +static int __init ttc_setup_clocksource(struct clk *clk, void __iomem *base, + u32 timer_width) +{ + struct ttc_timer_clocksource *ttccs; + int err; + + ttccs = kzalloc_obj(*ttccs); + if (!ttccs) + return -ENOMEM; + + ttccs->ttc.clk = clk; + + err = clk_prepare_enable(ttccs->ttc.clk); + if (err) { + kfree(ttccs); + return err; + } + + ttccs->ttc.freq = clk_get_rate(ttccs->ttc.clk); + + ttccs->ttc.clk_rate_change_nb.notifier_call = + ttc_rate_change_clocksource_cb; + ttccs->ttc.clk_rate_change_nb.next = NULL; + + err = clk_notifier_register(ttccs->ttc.clk, + &ttccs->ttc.clk_rate_change_nb); + if (err) + pr_warn("Unable to register clock notifier.\n"); + + ttccs->ttc.base_addr = base; + ttccs->cs.name = "ttc_clocksource"; + ttccs->cs.rating = 200; + ttccs->cs.read = __ttc_clocksource_read; + ttccs->cs.mask = CLOCKSOURCE_MASK(timer_width); + ttccs->cs.flags = CLOCK_SOURCE_IS_CONTINUOUS; + + /* + * Setup the clock source counter to be an incrementing counter + * with no interrupt and it rolls over at 0xFFFF. Pre-scale + * it by 32 also. Let it start running now. + */ + writel_relaxed(0x0, ttccs->ttc.base_addr + TTC_IER_OFFSET); + writel_relaxed(CLK_CNTRL_PRESCALE | CLK_CNTRL_PRESCALE_EN, + ttccs->ttc.base_addr + TTC_CLK_CNTRL_OFFSET); + writel_relaxed(CNT_CNTRL_RESET, + ttccs->ttc.base_addr + TTC_CNT_CNTRL_OFFSET); + + err = clocksource_register_hz(&ttccs->cs, ttccs->ttc.freq / PRESCALE); + if (err) { + kfree(ttccs); + return err; + } + + ttc_sched_clock_val_reg = base + TTC_COUNT_VAL_OFFSET; + sched_clock_register(ttc_sched_clock_read, timer_width, + ttccs->ttc.freq / PRESCALE); + + return 0; +} + +static int ttc_rate_change_clockevent_cb(struct notifier_block *nb, + unsigned long event, void *data) +{ + struct clk_notifier_data *ndata = data; + struct ttc_timer *ttc = to_ttc_timer(nb); + struct ttc_timer_clockevent *ttcce = container_of(ttc, + struct ttc_timer_clockevent, ttc); + + switch (event) { + case POST_RATE_CHANGE: + /* update cached frequency */ + ttc->freq = ndata->new_rate; + + clockevents_update_freq(&ttcce->ce, ndata->new_rate / PRESCALE); + + fallthrough; + case PRE_RATE_CHANGE: + case ABORT_RATE_CHANGE: + default: + return NOTIFY_DONE; + } +} + +static int __init ttc_setup_clockevent(struct clk *clk, + void __iomem *base, u32 irq) +{ + struct ttc_timer_clockevent *ttcce; + int err; + + ttcce = kzalloc_obj(*ttcce); + if (!ttcce) + return -ENOMEM; + + ttcce->ttc.clk = clk; + + err = clk_prepare_enable(ttcce->ttc.clk); + if (err) + goto out_kfree; + + ttcce->ttc.clk_rate_change_nb.notifier_call = + ttc_rate_change_clockevent_cb; + ttcce->ttc.clk_rate_change_nb.next = NULL; + + err = clk_notifier_register(ttcce->ttc.clk, + &ttcce->ttc.clk_rate_change_nb); + if (err) { + pr_warn("Unable to register clock notifier.\n"); + goto out_clk_unprepare; + } + + ttcce->ttc.freq = clk_get_rate(ttcce->ttc.clk); + + ttcce->ttc.base_addr = base; + ttcce->ce.name = "ttc_clockevent"; + ttcce->ce.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT; + ttcce->ce.set_next_event = ttc_set_next_event; + ttcce->ce.set_state_shutdown = ttc_shutdown; + ttcce->ce.set_state_periodic = ttc_set_periodic; + ttcce->ce.set_state_oneshot = ttc_shutdown; + ttcce->ce.tick_resume = ttc_resume; + ttcce->ce.rating = 200; + ttcce->ce.irq = irq; + ttcce->ce.cpumask = cpu_possible_mask; + + /* + * Setup the clock event timer to be an interval timer which + * is prescaled by 32 using the interval interrupt. Leave it + * disabled for now. + */ + writel_relaxed(0x23, ttcce->ttc.base_addr + TTC_CNT_CNTRL_OFFSET); + writel_relaxed(CLK_CNTRL_PRESCALE | CLK_CNTRL_PRESCALE_EN, + ttcce->ttc.base_addr + TTC_CLK_CNTRL_OFFSET); + writel_relaxed(0x1, ttcce->ttc.base_addr + TTC_IER_OFFSET); + + err = request_irq(irq, ttc_clock_event_interrupt, + IRQF_TIMER, ttcce->ce.name, ttcce); + if (err) + goto out_clk_unprepare; + + clockevents_config_and_register(&ttcce->ce, + ttcce->ttc.freq / PRESCALE, 1, 0xfffe); + + return 0; + +out_clk_unprepare: + clk_disable_unprepare(ttcce->ttc.clk); +out_kfree: + kfree(ttcce); + return err; +} + +static int __init ttc_timer_probe(struct platform_device *pdev) +{ + unsigned int irq; + void __iomem *timer_baseaddr; + struct clk *clk_cs, *clk_ce; + static int initialized; + int clksel, ret; + u32 timer_width = 16; + struct device_node *timer = pdev->dev.of_node; + + if (initialized) + return 0; + + initialized = 1; + + /* + * Get the 1st Triple Timer Counter (TTC) block from the device tree + * and use it. Note that the event timer uses the interrupt and it's the + * 2nd TTC hence the irq_of_parse_and_map(,1) + */ + timer_baseaddr = devm_of_iomap(&pdev->dev, timer, 0, NULL); + if (IS_ERR(timer_baseaddr)) { + pr_err("ERROR: invalid timer base address\n"); + return PTR_ERR(timer_baseaddr); + } + + irq = irq_of_parse_and_map(timer, 1); + if (irq <= 0) { + pr_err("ERROR: invalid interrupt number\n"); + return -EINVAL; + } + + of_property_read_u32(timer, "timer-width", &timer_width); + + clksel = readl_relaxed(timer_baseaddr + TTC_CLK_CNTRL_OFFSET); + clksel = !!(clksel & TTC_CLK_CNTRL_CSRC_MASK); + clk_cs = of_clk_get(timer, clksel); + if (IS_ERR(clk_cs)) { + pr_err("ERROR: timer input clock not found\n"); + return PTR_ERR(clk_cs); + } + + clksel = readl_relaxed(timer_baseaddr + 4 + TTC_CLK_CNTRL_OFFSET); + clksel = !!(clksel & TTC_CLK_CNTRL_CSRC_MASK); + clk_ce = of_clk_get(timer, clksel); + if (IS_ERR(clk_ce)) { + pr_err("ERROR: timer input clock not found\n"); + ret = PTR_ERR(clk_ce); + goto put_clk_cs; + } + + ret = ttc_setup_clocksource(clk_cs, timer_baseaddr, timer_width); + if (ret) + goto put_clk_ce; + + ret = ttc_setup_clockevent(clk_ce, timer_baseaddr + 4, irq); + if (ret) + goto put_clk_ce; + + pr_info("%pOFn #0 at %p, irq=%d\n", timer, timer_baseaddr, irq); + + return 0; + +put_clk_ce: + clk_put(clk_ce); +put_clk_cs: + clk_put(clk_cs); + return ret; +} + +static const struct of_device_id ttc_timer_of_match[] = { + {.compatible = "cdns,ttc"}, + {}, +}; + +MODULE_DEVICE_TABLE(of, ttc_timer_of_match); + +static struct platform_driver ttc_timer_driver = { + .driver = { + .name = "cdns_ttc_timer", + .of_match_table = ttc_timer_of_match, + }, +}; +builtin_platform_driver_probe(ttc_timer_driver, ttc_timer_probe); |
