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Subject[PATCH v4 3/4] clocksource/drivers/exynos_mct: Support local-timers property
Date
If the device tree indicates that the hardware requires that the
processor only use certain local timers, respect that.

Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
---

Notes:
v4:
- Add function documentation
- Add const for local_idx
- Rename irqidx -> irq_idx
- Error out on invalid number of CPUs

v3:
- Use array in devicetree
- Remove addition of global variable
- Split out FRC sharing changes

drivers/clocksource/exynos_mct.c | 62 ++++++++++++++++++++++++++++----
1 file changed, 56 insertions(+), 6 deletions(-)

diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c
index 12023831dedf..bfd60093ee1c 100644
--- a/drivers/clocksource/exynos_mct.c
+++ b/drivers/clocksource/exynos_mct.c
@@ -33,7 +33,7 @@
#define EXYNOS4_MCT_G_INT_ENB EXYNOS4_MCTREG(0x248)
#define EXYNOS4_MCT_G_WSTAT EXYNOS4_MCTREG(0x24C)
#define _EXYNOS4_MCT_L_BASE EXYNOS4_MCTREG(0x300)
-#define EXYNOS4_MCT_L_BASE(x) (_EXYNOS4_MCT_L_BASE + (0x100 * x))
+#define EXYNOS4_MCT_L_BASE(x) (_EXYNOS4_MCT_L_BASE + (0x100 * (x)))
#define EXYNOS4_MCT_L_MASK (0xffffff00)

#define MCT_L_TCNTB_OFFSET (0x00)
@@ -66,6 +66,8 @@
#define MCT_L0_IRQ 4
/* Max number of IRQ as per DT binding document */
#define MCT_NR_IRQS 20
+/* Max number of local timers */
+#define MCT_NR_LOCAL (MCT_NR_IRQS - MCT_L0_IRQ)

enum {
MCT_INT_SPI,
@@ -456,7 +458,6 @@ static int exynos4_mct_starting_cpu(unsigned int cpu)
per_cpu_ptr(&percpu_mct_tick, cpu);
struct clock_event_device *evt = &mevt->evt;

- mevt->base = EXYNOS4_MCT_L_BASE(cpu);
snprintf(mevt->name, sizeof(mevt->name), "mct_tick%d", cpu);

evt->name = mevt->name;
@@ -527,8 +528,17 @@ static int __init exynos4_timer_resources(struct device_node *np)
return 0;
}

+/**
+ * exynos4_timer_interrupts - initialize MCT interrupts
+ * @np: device node for MCT
+ * @int_type: interrupt type, MCT_INT_PPI or MCT_INT_SPI
+ * @local_idx: array mapping CPU numbers to local timer indices
+ * @nr_local: size of @local_idx array
+ */
static int __init exynos4_timer_interrupts(struct device_node *np,
- unsigned int int_type)
+ unsigned int int_type,
+ const u32 *local_idx,
+ size_t nr_local)
{
int nr_irqs, i, err, cpu;

@@ -561,13 +571,21 @@ static int __init exynos4_timer_interrupts(struct device_node *np,
} else {
for_each_possible_cpu(cpu) {
int mct_irq;
+ unsigned int irq_idx;
struct mct_clock_event_device *pcpu_mevt =
per_cpu_ptr(&percpu_mct_tick, cpu);

+ if (cpu >= nr_local) {
+ err = -EINVAL;
+ goto out_irq;
+ }
+
+ irq_idx = MCT_L0_IRQ + local_idx[cpu];
+
pcpu_mevt->evt.irq = -1;
- if (MCT_L0_IRQ + cpu >= ARRAY_SIZE(mct_irqs))
+ if (irq_idx >= ARRAY_SIZE(mct_irqs))
break;
- mct_irq = mct_irqs[MCT_L0_IRQ + cpu];
+ mct_irq = mct_irqs[irq_idx];

irq_set_status_flags(mct_irq, IRQ_NOAUTOEN);
if (request_irq(mct_irq,
@@ -583,6 +601,17 @@ static int __init exynos4_timer_interrupts(struct device_node *np,
}
}

+ for_each_possible_cpu(cpu) {
+ struct mct_clock_event_device *mevt = per_cpu_ptr(&percpu_mct_tick, cpu);
+
+ if (cpu >= nr_local) {
+ err = -EINVAL;
+ goto out_irq;
+ }
+
+ mevt->base = EXYNOS4_MCT_L_BASE(local_idx[cpu]);
+ }
+
/* Install hotplug callbacks which configure the timer on this CPU */
err = cpuhp_setup_state(CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING,
"clockevents/exynos4/mct_timer:starting",
@@ -613,13 +642,34 @@ static int __init exynos4_timer_interrupts(struct device_node *np,
static int __init mct_init_dt(struct device_node *np, unsigned int int_type)
{
bool frc_shared = of_property_read_bool(np, "samsung,frc-shared");
+ u32 local_idx[MCT_NR_LOCAL] = {0};
+ int nr_local;
int ret;

+ nr_local = of_property_count_u32_elems(np, "samsung,local-timers");
+ if (nr_local == 0)
+ return -EINVAL;
+ if (nr_local > 0) {
+ if (nr_local > ARRAY_SIZE(local_idx))
+ return -EINVAL;
+
+ ret = of_property_read_u32_array(np, "samsung,local-timers",
+ local_idx, nr_local);
+ if (ret)
+ return ret;
+ } else {
+ int i;
+
+ nr_local = ARRAY_SIZE(local_idx);
+ for (i = 0; i < nr_local; i++)
+ local_idx[i] = i;
+ }
+
ret = exynos4_timer_resources(np);
if (ret)
return ret;

- ret = exynos4_timer_interrupts(np, int_type);
+ ret = exynos4_timer_interrupts(np, int_type, local_idx, nr_local);
if (ret)
return ret;

--
2.34.1
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