[PATCH 2/6] clocksource: Ingenic: Add high resolution timer support for SMP.

From: åçæ (Zhou Yanjie)
Date: Mon Jan 13 2020 - 11:44:27 EST


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.

Signed-off-by: åçæ (Zhou Yanjie) <zhouyanjie@xxxxxxxxxxxxxx>
---
drivers/clocksource/ingenic-timer.c | 114 +++++++++++++++++++++++++++++-------
1 file changed, 93 insertions(+), 21 deletions(-)

diff --git a/drivers/clocksource/ingenic-timer.c b/drivers/clocksource/ingenic-timer.c
index 4bbdb3d..1d32652 100644
--- a/drivers/clocksource/ingenic-timer.c
+++ b/drivers/clocksource/ingenic-timer.c
@@ -1,7 +1,8 @@
// SPDX-License-Identifier: GPL-2.0
/*
- * JZ47xx SoCs TCU IRQ driver
+ * XBurst SoCs TCU IRQ driver
* Copyright (C) 2019 Paul Cercueil <paul@xxxxxxxxxxxxxxx>
+ * Copyright (C) 2020 åçæ (Zhou Yanjie) <zhouyanjie@xxxxxxxxxxxxxx>
*/

#include <linux/bitops.h>
@@ -27,12 +28,15 @@ struct ingenic_soc_info {

struct ingenic_tcu {
struct regmap *map;
+ struct device_node *np;
struct clk *timer_clk, *cs_clk;
+ unsigned int timer_local[NR_CPUS];
unsigned int timer_channel, cs_channel;
struct clock_event_device cevt;
struct clocksource cs;
- char name[4];
+ char name[16];
unsigned long pwm_channels_mask;
+ int cpu;
};

static struct ingenic_tcu *ingenic_tcu;
@@ -81,6 +85,30 @@ static int ingenic_tcu_cevt_set_next(unsigned long next,
return 0;
}

+static void ingenic_per_cpu_event_handle(void *info)
+{
+ struct clock_event_device *cevt = (struct clock_event_device *) info;
+
+ if (cevt->event_handler)
+ cevt->event_handler(cevt);
+}
+
+static void ingenic_tcu_per_cpu_cb(struct clock_event_device *evt)
+{
+ struct clock_event_device *cevt = evt;
+ struct ingenic_tcu *tcu = to_ingenic_tcu(evt);
+
+ if (smp_processor_id() == tcu->cpu) {
+ if (cevt->event_handler)
+ cevt->event_handler(cevt);
+ } else {
+ arch_local_irq_enable();
+ smp_call_function_single(tcu->cpu,
+ ingenic_per_cpu_event_handle, (void *) cevt, 0);
+ arch_local_irq_disable();
+ }
+}
+
static irqreturn_t ingenic_tcu_cevt_cb(int irq, void *dev_id)
{
struct clock_event_device *evt = dev_id;
@@ -88,8 +116,7 @@ static irqreturn_t ingenic_tcu_cevt_cb(int irq, void *dev_id)

regmap_write(tcu->map, TCU_REG_TECR, BIT(tcu->timer_channel));

- if (evt->event_handler)
- evt->event_handler(evt);
+ ingenic_tcu_per_cpu_cb(evt);

return IRQ_HANDLED;
}
@@ -105,15 +132,23 @@ 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(struct device_node *np,
+ unsigned int channel)
{
- unsigned int timer_virq, channel = tcu->timer_channel;
+ unsigned int timer_virq;
struct irq_domain *domain;
+ struct ingenic_tcu *tcu;
unsigned long rate;
int err;

+ tcu = kzalloc(sizeof(*tcu), GFP_KERNEL);
+ if (!tcu)
+ return -ENOMEM;
+
+ tcu->map = ingenic_tcu->map;
+
tcu->timer_clk = ingenic_tcu_get_clock(np, channel);
+
if (IS_ERR(tcu->timer_clk))
return PTR_ERR(tcu->timer_clk);

@@ -139,13 +174,15 @@ static int __init ingenic_tcu_timer_init(struct device_node *np,
goto err_clk_disable;
}

- snprintf(tcu->name, sizeof(tcu->name), "TCU");
+ snprintf(tcu->name, sizeof(tcu->name), "TCU channel.%u", channel);

err = request_irq(timer_virq, ingenic_tcu_cevt_cb, IRQF_TIMER,
tcu->name, &tcu->cevt);
if (err)
goto err_irq_dispose_mapping;

+ tcu->cpu = smp_processor_id();
+ tcu->timer_channel = channel;
tcu->cevt.cpumask = cpumask_of(smp_processor_id());
tcu->cevt.features = CLOCK_EVT_FEAT_ONESHOT;
tcu->cevt.name = tcu->name;
@@ -233,12 +270,32 @@ static const struct of_device_id ingenic_tcu_of_match[] = {
{ /* sentinel */ }
};

+static int register_cpu_online(unsigned int cpu)
+{
+ int ret;
+
+ ret = ingenic_tcu_setup_cevt(ingenic_tcu->np,
+ ingenic_tcu->timer_local[cpu]);
+ if (ret)
+ goto err_tcu_clocksource_cleanup;
+
+ return 0;
+
+err_tcu_clocksource_cleanup:
+ clocksource_unregister(&ingenic_tcu->cs);
+ clk_disable_unprepare(ingenic_tcu->cs_clk);
+ clk_put(ingenic_tcu->cs_clk);
+ kfree(ingenic_tcu);
+ return ret;
+}
+
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 *tcu;
struct regmap *map;
+ unsigned cpu = 0;
long rate;
int ret;

@@ -253,12 +310,14 @@ static int __init ingenic_tcu_init(struct device_node *np)
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);
+ tcu->pwm_channels_mask = GENMASK(soc_info->num_channels - 1,
+ NR_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) {
+ if (hweight8(tcu->pwm_channels_mask) >
+ soc_info->num_channels - NR_CPUS + 1) {
pr_crit("%s: Invalid PWM channel mask: 0x%02lx\n", __func__,
tcu->pwm_channels_mask);
ret = -EINVAL;
@@ -266,13 +325,29 @@ 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,
+ tcu->timer_local[cpu] = find_first_zero_bit(&tcu->pwm_channels_mask,
soc_info->num_channels);
- tcu->cs_channel = find_next_zero_bit(&tcu->pwm_channels_mask,
- soc_info->num_channels,
- tcu->timer_channel + 1);
+
+ if (NR_CPUS > 1) {
+ for (cpu = 1; cpu < NR_CPUS; cpu++)
+ tcu->timer_local[cpu] = find_next_zero_bit(
+ &tcu->pwm_channels_mask,
+ soc_info->num_channels,
+ tcu->timer_local[cpu - 1] + 1);
+
+ tcu->cs_channel = find_next_zero_bit(&tcu->pwm_channels_mask,
+ soc_info->num_channels,
+ tcu->timer_local[cpu-1] + 1);
+ } else {
+ tcu->cs_channel = find_next_zero_bit(&tcu->pwm_channels_mask,
+ soc_info->num_channels,
+ tcu->timer_local[cpu] + 1);
+ }
+
+

ret = ingenic_tcu_clocksource_init(np, tcu);
if (ret) {
@@ -280,9 +355,10 @@ static int __init ingenic_tcu_init(struct device_node *np)
goto err_free_ingenic_tcu;
}

- ret = ingenic_tcu_timer_init(np, tcu);
- if (ret)
- goto err_tcu_clocksource_cleanup;
+ /* Setup clock events on each CPU core */
+ ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "Ingenic XBurst: online",
+ register_cpu_online, NULL);
+ WARN_ON(ret < 0);

/* Register the sched_clock at the end as there's no way to undo it */
rate = clk_get_rate(tcu->cs_clk);
@@ -290,10 +366,6 @@ static int __init ingenic_tcu_init(struct device_node *np)

return 0;

-err_tcu_clocksource_cleanup:
- clocksource_unregister(&tcu->cs);
- clk_disable_unprepare(tcu->cs_clk);
- clk_put(tcu->cs_clk);
err_free_ingenic_tcu:
kfree(tcu);
return ret;
--
2.7.4