From: 周琰杰 (Zhou Yanjie) <zhouyan...@wanyeetech.com>

Enable clock event handling on per CPU core basis.
Make sure that interrupts raised on the first core execute
event handlers on the correct CPU core.

Tested-by: H. Nikolaus Schaller <h...@goldelico.com>
Tested-by: Paul Boddie <p...@boddie.org.uk>
Signed-off-by: 周琰杰 (Zhou Yanjie) <zhouyan...@wanyeetech.com>
Signed-off-by: Paul Cercueil <p...@crapouillou.net>
---

Zhou:

I took the liberty to clean your patch so that it doesn't create a
struct ingenic_tcu per CPU timer.

Tested, and fully working on the JZ4770 with CONFIG_SMP disabled, and
also with CONFIG_SMP enabled (even though JZ4770 has only one CPU) with
a fixed smp.c and USB disabled (otherwise it crashes at boot).

Cheers,
-Paul

 drivers/clocksource/ingenic-timer.c | 180 +++++++++++++++++++---------
 1 file changed, 123 insertions(+), 57 deletions(-)

diff --git a/drivers/clocksource/ingenic-timer.c 
b/drivers/clocksource/ingenic-timer.c
index 496333650de2..a068e4620c44 100644
--- a/drivers/clocksource/ingenic-timer.c
+++ b/drivers/clocksource/ingenic-timer.c
@@ -2,6 +2,7 @@
 /*
  * JZ47xx SoCs TCU IRQ driver
  * Copyright (C) 2019 Paul Cercueil <p...@crapouillou.net>
+ * Copyright (C) 2020 周琰杰 (Zhou Yanjie) <zhouyan...@wanyeetech.com>
  */
 
 #include <linux/bitops.h>
@@ -15,24 +16,35 @@
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 #include <linux/of_platform.h>
+#include <linux/overflow.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
 #include <linux/sched_clock.h>
 
 #include <dt-bindings/clock/ingenic,tcu.h>
 
+static DEFINE_PER_CPU(call_single_data_t, ingenic_cevt_csd);
+
 struct ingenic_soc_info {
        unsigned int num_channels;
 };
 
+struct ingenic_tcu_timer {
+       unsigned int cpu;
+       unsigned int channel;
+       struct clock_event_device cevt;
+       struct clk *clk;
+       char name[8];
+};
+
 struct ingenic_tcu {
        struct regmap *map;
-       struct clk *timer_clk, *cs_clk;
-       unsigned int timer_channel, cs_channel;
-       struct clock_event_device cevt;
+       struct device_node *np;
+       struct clk *cs_clk;
+       unsigned int cs_channel;
        struct clocksource cs;
-       char name[4];
        unsigned long pwm_channels_mask;
+       struct ingenic_tcu_timer timers[];
 };
 
 static struct ingenic_tcu *ingenic_tcu;
@@ -52,16 +64,24 @@ static u64 notrace ingenic_tcu_timer_cs_read(struct 
clocksource *cs)
        return ingenic_tcu_timer_read();
 }
 
-static inline struct ingenic_tcu *to_ingenic_tcu(struct clock_event_device 
*evt)
+static inline struct ingenic_tcu *
+to_ingenic_tcu(struct ingenic_tcu_timer *timer)
+{
+       return container_of(timer, struct ingenic_tcu, timers[timer->cpu]);
+}
+
+static inline struct ingenic_tcu_timer *
+to_ingenic_tcu_timer(struct clock_event_device *evt)
 {
-       return container_of(evt, struct ingenic_tcu, cevt);
+       return container_of(evt, struct ingenic_tcu_timer, cevt);
 }
 
 static int ingenic_tcu_cevt_set_state_shutdown(struct clock_event_device *evt)
 {
-       struct ingenic_tcu *tcu = to_ingenic_tcu(evt);
+       struct ingenic_tcu_timer *timer = to_ingenic_tcu_timer(evt);
+       struct ingenic_tcu *tcu = to_ingenic_tcu(timer);
 
-       regmap_write(tcu->map, TCU_REG_TECR, BIT(tcu->timer_channel));
+       regmap_write(tcu->map, TCU_REG_TECR, BIT(timer->channel));
 
        return 0;
 }
@@ -69,27 +89,40 @@ static int ingenic_tcu_cevt_set_state_shutdown(struct 
clock_event_device *evt)
 static int ingenic_tcu_cevt_set_next(unsigned long next,
                                     struct clock_event_device *evt)
 {
-       struct ingenic_tcu *tcu = to_ingenic_tcu(evt);
+       struct ingenic_tcu_timer *timer = to_ingenic_tcu_timer(evt);
+       struct ingenic_tcu *tcu = to_ingenic_tcu(timer);
 
        if (next > 0xffff)
                return -EINVAL;
 
-       regmap_write(tcu->map, TCU_REG_TDFRc(tcu->timer_channel), next);
-       regmap_write(tcu->map, TCU_REG_TCNTc(tcu->timer_channel), 0);
-       regmap_write(tcu->map, TCU_REG_TESR, BIT(tcu->timer_channel));
+       regmap_write(tcu->map, TCU_REG_TDFRc(timer->channel), next);
+       regmap_write(tcu->map, TCU_REG_TCNTc(timer->channel), 0);
+       regmap_write(tcu->map, TCU_REG_TESR, BIT(timer->channel));
 
        return 0;
 }
 
+static void ingenic_per_cpu_event_handler(void *info)
+{
+       struct clock_event_device *cevt = (struct clock_event_device *) info;
+
+       cevt->event_handler(cevt);
+}
+
 static irqreturn_t ingenic_tcu_cevt_cb(int irq, void *dev_id)
 {
-       struct clock_event_device *evt = dev_id;
-       struct ingenic_tcu *tcu = to_ingenic_tcu(evt);
+       struct ingenic_tcu_timer *timer = dev_id;
+       struct ingenic_tcu *tcu = to_ingenic_tcu(timer);
+       call_single_data_t *csd;
 
-       regmap_write(tcu->map, TCU_REG_TECR, BIT(tcu->timer_channel));
+       regmap_write(tcu->map, TCU_REG_TECR, BIT(timer->channel));
 
-       if (evt->event_handler)
-               evt->event_handler(evt);
+       if (timer->cevt.event_handler) {
+               csd = &per_cpu(ingenic_cevt_csd, timer->cpu);
+               csd->info = (void *) &timer->cevt;
+               csd->func = ingenic_per_cpu_event_handler;
+               smp_call_function_single_async(timer->cpu, csd);
+       }
 
        return IRQ_HANDLED;
 }
@@ -105,64 +138,66 @@ static struct clk * __init ingenic_tcu_get_clock(struct 
device_node *np, int id)
        return of_clk_get_from_provider(&args);
 }
 
-static int __init ingenic_tcu_timer_init(struct device_node *np,
-                                        struct ingenic_tcu *tcu)
+static int ingenic_tcu_setup_cevt(unsigned int cpu)
 {
-       unsigned int timer_virq, channel = tcu->timer_channel;
+       struct ingenic_tcu *tcu = ingenic_tcu;
+       struct ingenic_tcu_timer *timer = &tcu->timers[cpu];
+       unsigned int timer_virq;
        struct irq_domain *domain;
        unsigned long rate;
        int err;
 
-       tcu->timer_clk = ingenic_tcu_get_clock(np, channel);
-       if (IS_ERR(tcu->timer_clk))
-               return PTR_ERR(tcu->timer_clk);
+       timer->clk = ingenic_tcu_get_clock(tcu->np, timer->channel);
+       if (IS_ERR(timer->clk))
+               return PTR_ERR(timer->clk);
 
-       err = clk_prepare_enable(tcu->timer_clk);
+       err = clk_prepare_enable(timer->clk);
        if (err)
                goto err_clk_put;
 
-       rate = clk_get_rate(tcu->timer_clk);
+       rate = clk_get_rate(timer->clk);
        if (!rate) {
                err = -EINVAL;
                goto err_clk_disable;
        }
 
-       domain = irq_find_host(np);
+       domain = irq_find_host(tcu->np);
        if (!domain) {
                err = -ENODEV;
                goto err_clk_disable;
        }
 
-       timer_virq = irq_create_mapping(domain, channel);
+       timer_virq = irq_create_mapping(domain, timer->channel);
        if (!timer_virq) {
                err = -EINVAL;
                goto err_clk_disable;
        }
 
-       snprintf(tcu->name, sizeof(tcu->name), "TCU");
+       snprintf(timer->name, sizeof(timer->name), "TCU%u", timer->channel);
 
        err = request_irq(timer_virq, ingenic_tcu_cevt_cb, IRQF_TIMER,
-                         tcu->name, &tcu->cevt);
+                         timer->name, timer);
        if (err)
                goto err_irq_dispose_mapping;
 
-       tcu->cevt.cpumask = cpumask_of(smp_processor_id());
-       tcu->cevt.features = CLOCK_EVT_FEAT_ONESHOT;
-       tcu->cevt.name = tcu->name;
-       tcu->cevt.rating = 200;
-       tcu->cevt.set_state_shutdown = ingenic_tcu_cevt_set_state_shutdown;
-       tcu->cevt.set_next_event = ingenic_tcu_cevt_set_next;
+       timer->cpu = smp_processor_id();
+       timer->cevt.cpumask = cpumask_of(smp_processor_id());
+       timer->cevt.features = CLOCK_EVT_FEAT_ONESHOT;
+       timer->cevt.name = timer->name;
+       timer->cevt.rating = 200;
+       timer->cevt.set_state_shutdown = ingenic_tcu_cevt_set_state_shutdown;
+       timer->cevt.set_next_event = ingenic_tcu_cevt_set_next;
 
-       clockevents_config_and_register(&tcu->cevt, rate, 10, 0xffff);
+       clockevents_config_and_register(&timer->cevt, rate, 10, 0xffff);
 
        return 0;
 
 err_irq_dispose_mapping:
        irq_dispose_mapping(timer_virq);
 err_clk_disable:
-       clk_disable_unprepare(tcu->timer_clk);
+       clk_disable_unprepare(timer->clk);
 err_clk_put:
-       clk_put(tcu->timer_clk);
+       clk_put(timer->clk);
        return err;
 }
 
@@ -238,10 +273,12 @@ static int __init ingenic_tcu_init(struct device_node *np)
 {
        const struct of_device_id *id = of_match_node(ingenic_tcu_of_match, np);
        const struct ingenic_soc_info *soc_info = id->data;
+       struct ingenic_tcu_timer *timer;
        struct ingenic_tcu *tcu;
        struct regmap *map;
+       unsigned int cpu;
+       int ret, last_bit = -1;
        long rate;
-       int ret;
 
        of_node_clear_flag(np, OF_POPULATED);
 
@@ -249,17 +286,23 @@ static int __init ingenic_tcu_init(struct device_node *np)
        if (IS_ERR(map))
                return PTR_ERR(map);
 
-       tcu = kzalloc(sizeof(*tcu), GFP_KERNEL);
+       tcu = kzalloc(struct_size(tcu, timers, num_possible_cpus()),
+                     GFP_KERNEL);
        if (!tcu)
                return -ENOMEM;
 
-       /* Enable all TCU channels for PWM use by default except channels 0/1 */
-       tcu->pwm_channels_mask = GENMASK(soc_info->num_channels - 1, 2);
+       /*
+        * Enable all TCU channels for PWM use by default except channels 0/1,
+        * and channel 2 if target CPU is JZ4780 and SMP is selected.
+        */
+       tcu->pwm_channels_mask = GENMASK(soc_info->num_channels - 1,
+                                        num_possible_cpus() + 1);
        of_property_read_u32(np, "ingenic,pwm-channels-mask",
                             (u32 *)&tcu->pwm_channels_mask);
 
-       /* Verify that we have at least two free channels */
-       if (hweight8(tcu->pwm_channels_mask) > soc_info->num_channels - 2) {
+       /* Verify that we have at least num_possible_cpus() + 1 free channels */
+       if (hweight8(tcu->pwm_channels_mask) >
+                       soc_info->num_channels - num_possible_cpus() + 1) {
                pr_crit("%s: Invalid PWM channel mask: 0x%02lx\n", __func__,
                        tcu->pwm_channels_mask);
                ret = -EINVAL;
@@ -267,13 +310,22 @@ static int __init ingenic_tcu_init(struct device_node *np)
        }
 
        tcu->map = map;
+       tcu->np = np;
        ingenic_tcu = tcu;
 
-       tcu->timer_channel = find_first_zero_bit(&tcu->pwm_channels_mask,
-                                                soc_info->num_channels);
+       for (cpu = 0; cpu < num_possible_cpus(); cpu++) {
+               timer = &tcu->timers[cpu];
+
+               timer->cpu = cpu;
+               timer->channel = find_next_zero_bit(&tcu->pwm_channels_mask,
+                                                 soc_info->num_channels,
+                                                 last_bit + 1);
+               last_bit = timer->channel;
+       }
+
        tcu->cs_channel = find_next_zero_bit(&tcu->pwm_channels_mask,
                                             soc_info->num_channels,
-                                            tcu->timer_channel + 1);
+                                            last_bit + 1);
 
        ret = ingenic_tcu_clocksource_init(np, tcu);
        if (ret) {
@@ -281,9 +333,13 @@ static int __init ingenic_tcu_init(struct device_node *np)
                goto err_free_ingenic_tcu;
        }
 
-       ret = ingenic_tcu_timer_init(np, tcu);
-       if (ret)
+       /* Setup clock events on each CPU core */
+       ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "Ingenic XBurst: online",
+                               ingenic_tcu_setup_cevt, NULL);
+       if (ret < 0) {
+               pr_crit("%s: Unable to start CPU timers: %d\n", __func__, ret);
                goto err_tcu_clocksource_cleanup;
+       }
 
        /* Register the sched_clock at the end as there's no way to undo it */
        rate = clk_get_rate(tcu->cs_clk);
@@ -315,28 +371,38 @@ static int __init ingenic_tcu_probe(struct 
platform_device *pdev)
 static int __maybe_unused ingenic_tcu_suspend(struct device *dev)
 {
        struct ingenic_tcu *tcu = dev_get_drvdata(dev);
+       unsigned int cpu;
 
        clk_disable(tcu->cs_clk);
-       clk_disable(tcu->timer_clk);
+
+       for (cpu = 0; cpu < num_online_cpus(); cpu++)
+               clk_disable(tcu->timers[cpu].clk);
+
        return 0;
 }
 
 static int __maybe_unused ingenic_tcu_resume(struct device *dev)
 {
        struct ingenic_tcu *tcu = dev_get_drvdata(dev);
+       unsigned int cpu;
        int ret;
 
-       ret = clk_enable(tcu->timer_clk);
-       if (ret)
-               return ret;
+       for (cpu = 0; cpu < num_online_cpus(); cpu++) {
+               ret = clk_enable(tcu->timers[cpu].clk);
+               if (ret)
+                       goto err_timer_clk_disable;
+       }
 
        ret = clk_enable(tcu->cs_clk);
-       if (ret) {
-               clk_disable(tcu->timer_clk);
-               return ret;
-       }
+       if (ret)
+               goto err_timer_clk_disable;
 
        return 0;
+
+err_timer_clk_disable:
+       for (; cpu > 0; cpu--)
+               clk_disable(tcu->timers[cpu - 1].clk);
+       return ret;
 }
 
 static const struct dev_pm_ops __maybe_unused ingenic_tcu_pm_ops = {
-- 
2.26.2

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