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authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
commit4352b8aee98005853aa63f57d6377282de17a33f (patch)
tree27614d7a9ef05c32d089004e104364ce42324837 /drivers/clocksource/timer-rtl-otto.c
downloadlinux-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-rtl-otto.c')
-rw-r--r--drivers/clocksource/timer-rtl-otto.c303
1 files changed, 303 insertions, 0 deletions
diff --git a/drivers/clocksource/timer-rtl-otto.c b/drivers/clocksource/timer-rtl-otto.c
new file mode 100644
index 000000000..0d1b9a01a
--- /dev/null
+++ b/drivers/clocksource/timer-rtl-otto.c
@@ -0,0 +1,303 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/clk.h>
+#include <linux/clockchips.h>
+#include <linux/cpu.h>
+#include <linux/cpuhotplug.h>
+#include <linux/cpumask.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/jiffies.h>
+#include <linux/printk.h>
+#include <linux/sched_clock.h>
+#include "timer-of.h"
+
+#define RTTM_DATA 0x0
+#define RTTM_CNT 0x4
+#define RTTM_CTRL 0x8
+#define RTTM_INT 0xc
+
+#define RTTM_CTRL_ENABLE BIT(28)
+#define RTTM_INT_PENDING BIT(16)
+#define RTTM_INT_ENABLE BIT(20)
+
+/*
+ * The Otto platform provides multiple 28 bit timers/counters with the following
+ * operating logic. If enabled the timer counts up. Per timer one can set a
+ * maximum counter value as an end marker. If end marker is reached the timer
+ * fires an interrupt. If the timer "overflows" by reaching the end marker or
+ * by adding 1 to 0x0fffffff the counter is reset to 0. When this happens and
+ * the timer is in operating mode COUNTER it stops. In mode TIMER it will
+ * continue to count up.
+ */
+#define RTTM_CTRL_COUNTER 0
+#define RTTM_CTRL_TIMER BIT(24)
+
+#define RTTM_BIT_COUNT 28
+#define RTTM_MIN_DELTA 8
+#define RTTM_MAX_DELTA CLOCKSOURCE_MASK(28)
+#define RTTM_MAX_DIVISOR GENMASK(15, 0)
+
+/*
+ * Timers are derived from the lexra bus (LXB) clock frequency. This is 175 MHz
+ * on RTL930x and 200 MHz on the other platforms. With 3.125 MHz choose a common
+ * divisor to have enough range and detail. This provides comparability between
+ * the different platforms.
+ */
+#define RTTM_TICKS_PER_SEC 3125000
+
+struct rttm_cs {
+ struct timer_of to;
+ struct clocksource cs;
+};
+
+/* Simple internal register functions */
+static inline unsigned int rttm_get_counter(void __iomem *base)
+{
+ return __raw_readl(base + RTTM_CNT);
+}
+
+static inline void rttm_set_period(void __iomem *base, unsigned int period)
+{
+ __raw_writel(period, base + RTTM_DATA);
+}
+
+static inline void rttm_disable_timer(void __iomem *base)
+{
+ __raw_writel(0, base + RTTM_CTRL);
+}
+
+static inline void rttm_enable_timer(void __iomem *base, u32 mode, u32 divisor)
+{
+ __raw_writel(RTTM_CTRL_ENABLE | mode | divisor, base + RTTM_CTRL);
+}
+
+static inline void rttm_ack_irq(void __iomem *base)
+{
+ __raw_writel(__raw_readl(base + RTTM_INT) | RTTM_INT_PENDING, base + RTTM_INT);
+}
+
+static inline void rttm_enable_irq(void __iomem *base)
+{
+ __raw_writel(RTTM_INT_ENABLE, base + RTTM_INT);
+}
+
+static inline void rttm_disable_irq(void __iomem *base)
+{
+ __raw_writel(0, base + RTTM_INT);
+}
+
+/* Aggregated control functions for kernel clock framework */
+#define RTTM_DEBUG(base) \
+ pr_debug("------------- %d %p\n", \
+ smp_processor_id(), base)
+
+static irqreturn_t rttm_timer_interrupt(int irq, void *dev_id)
+{
+ struct clock_event_device *clkevt = dev_id;
+ struct timer_of *to = to_timer_of(clkevt);
+
+ rttm_ack_irq(to->of_base.base);
+ RTTM_DEBUG(to->of_base.base);
+ clkevt->event_handler(clkevt);
+
+ return IRQ_HANDLED;
+}
+
+static void rttm_bounce_timer(void __iomem *base, u32 mode)
+{
+ /*
+ * When a running timer has less than ~5us left, a stop/start sequence
+ * might fail. While the details are unknown the most evident effect is
+ * that the subsequent interrupt will not be fired.
+ *
+ * As a workaround issue an intermediate restart with a very slow
+ * frequency of ~3kHz keeping the target counter (>=8). So the follow
+ * up restart will always be issued outside the critical window.
+ */
+
+ rttm_disable_timer(base);
+ rttm_enable_timer(base, mode, RTTM_MAX_DIVISOR);
+}
+
+static void rttm_stop_timer(void __iomem *base)
+{
+ rttm_disable_timer(base);
+ rttm_ack_irq(base);
+}
+
+static void rttm_start_timer(struct timer_of *to, u32 mode)
+{
+ rttm_enable_timer(to->of_base.base, mode, to->of_clk.rate / RTTM_TICKS_PER_SEC);
+}
+
+static int rttm_next_event(unsigned long delta, struct clock_event_device *clkevt)
+{
+ struct timer_of *to = to_timer_of(clkevt);
+
+ RTTM_DEBUG(to->of_base.base);
+ rttm_bounce_timer(to->of_base.base, RTTM_CTRL_COUNTER);
+ rttm_disable_timer(to->of_base.base);
+ rttm_set_period(to->of_base.base, delta);
+ rttm_start_timer(to, RTTM_CTRL_COUNTER);
+
+ return 0;
+}
+
+static int rttm_state_oneshot(struct clock_event_device *clkevt)
+{
+ struct timer_of *to = to_timer_of(clkevt);
+
+ RTTM_DEBUG(to->of_base.base);
+ rttm_bounce_timer(to->of_base.base, RTTM_CTRL_COUNTER);
+ rttm_disable_timer(to->of_base.base);
+ rttm_set_period(to->of_base.base, RTTM_TICKS_PER_SEC / HZ);
+ rttm_start_timer(to, RTTM_CTRL_COUNTER);
+
+ return 0;
+}
+
+static int rttm_state_periodic(struct clock_event_device *clkevt)
+{
+ struct timer_of *to = to_timer_of(clkevt);
+
+ RTTM_DEBUG(to->of_base.base);
+ rttm_bounce_timer(to->of_base.base, RTTM_CTRL_TIMER);
+ rttm_disable_timer(to->of_base.base);
+ rttm_set_period(to->of_base.base, RTTM_TICKS_PER_SEC / HZ);
+ rttm_start_timer(to, RTTM_CTRL_TIMER);
+
+ return 0;
+}
+
+static int rttm_state_shutdown(struct clock_event_device *clkevt)
+{
+ struct timer_of *to = to_timer_of(clkevt);
+
+ RTTM_DEBUG(to->of_base.base);
+ rttm_stop_timer(to->of_base.base);
+
+ return 0;
+}
+
+static void rttm_setup_timer(void __iomem *base)
+{
+ RTTM_DEBUG(base);
+ rttm_stop_timer(base);
+ rttm_set_period(base, 0);
+}
+
+static u64 rttm_read_clocksource(struct clocksource *cs)
+{
+ struct rttm_cs *rcs = container_of(cs, struct rttm_cs, cs);
+
+ return rttm_get_counter(rcs->to.of_base.base);
+}
+
+/* Module initialization part. */
+static DEFINE_PER_CPU(struct timer_of, rttm_to) = {
+ .flags = TIMER_OF_BASE | TIMER_OF_CLOCK | TIMER_OF_IRQ,
+ .of_irq = {
+ .flags = IRQF_PERCPU | IRQF_TIMER,
+ .handler = rttm_timer_interrupt,
+ },
+ .clkevt = {
+ .rating = 400,
+ .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+ .set_state_periodic = rttm_state_periodic,
+ .set_state_shutdown = rttm_state_shutdown,
+ .set_state_oneshot = rttm_state_oneshot,
+ .set_next_event = rttm_next_event
+ },
+};
+
+static int rttm_enable_clocksource(struct clocksource *cs)
+{
+ struct rttm_cs *rcs = container_of(cs, struct rttm_cs, cs);
+
+ rttm_disable_irq(rcs->to.of_base.base);
+ rttm_setup_timer(rcs->to.of_base.base);
+ rttm_enable_timer(rcs->to.of_base.base, RTTM_CTRL_TIMER,
+ rcs->to.of_clk.rate / RTTM_TICKS_PER_SEC);
+
+ return 0;
+}
+
+static struct rttm_cs rttm_cs = {
+ .to = {
+ .flags = TIMER_OF_BASE | TIMER_OF_CLOCK,
+ },
+ .cs = {
+ .name = "realtek_otto_timer",
+ .rating = 400,
+ .mask = CLOCKSOURCE_MASK(RTTM_BIT_COUNT),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+ .read = rttm_read_clocksource,
+ }
+};
+
+static u64 notrace rttm_read_clock(void)
+{
+ return rttm_get_counter(rttm_cs.to.of_base.base);
+}
+
+static int rttm_cpu_starting(unsigned int cpu)
+{
+ struct timer_of *to = per_cpu_ptr(&rttm_to, cpu);
+
+ RTTM_DEBUG(to->of_base.base);
+ to->clkevt.cpumask = cpumask_of(cpu);
+ irq_force_affinity(to->of_irq.irq, to->clkevt.cpumask);
+ clockevents_config_and_register(&to->clkevt, RTTM_TICKS_PER_SEC,
+ RTTM_MIN_DELTA, RTTM_MAX_DELTA);
+ rttm_enable_irq(to->of_base.base);
+
+ return 0;
+}
+
+static int __init rttm_probe(struct device_node *np)
+{
+ unsigned int cpu, cpu_rollback;
+ struct timer_of *to;
+ unsigned int clkidx = num_possible_cpus();
+
+ /* Use the first n timers as per CPU clock event generators */
+ for_each_possible_cpu(cpu) {
+ to = per_cpu_ptr(&rttm_to, cpu);
+ to->of_irq.index = to->of_base.index = cpu;
+ if (timer_of_init(np, to)) {
+ pr_err("setup of timer %d failed\n", cpu);
+ goto rollback;
+ }
+ rttm_setup_timer(to->of_base.base);
+ }
+
+ /* Activate the n'th + 1 timer as a stable CPU clocksource. */
+ to = &rttm_cs.to;
+ to->of_base.index = clkidx;
+ timer_of_init(np, to);
+ if (rttm_cs.to.of_base.base && rttm_cs.to.of_clk.rate) {
+ rttm_enable_clocksource(&rttm_cs.cs);
+ clocksource_register_hz(&rttm_cs.cs, RTTM_TICKS_PER_SEC);
+ sched_clock_register(rttm_read_clock, RTTM_BIT_COUNT, RTTM_TICKS_PER_SEC);
+ } else
+ pr_err(" setup of timer %d as clocksource failed", clkidx);
+
+ return cpuhp_setup_state(CPUHP_AP_REALTEK_TIMER_STARTING,
+ "timer/realtek:online",
+ rttm_cpu_starting, NULL);
+rollback:
+ pr_err("timer registration failed\n");
+ for_each_possible_cpu(cpu_rollback) {
+ if (cpu_rollback == cpu)
+ break;
+ to = per_cpu_ptr(&rttm_to, cpu_rollback);
+ timer_of_cleanup(to);
+ }
+
+ return -EINVAL;
+}
+
+TIMER_OF_DECLARE(otto_timer, "realtek,otto-timer", rttm_probe);