[PATCH v2 3/3] clocksource/drivers/timer-clint: Add T-Head C9xx clint

Jisheng Zhang
2024-04-06T11:35:34Z

The mtimecmp in T-Head C9xx clint only supports 32bit read/write,
implement such support.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
---
drivers/clocksource/timer-clint.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)

diff --git a/drivers/clocksource/timer-clint.c b/drivers/clocksource/timer-clint.c
index 0d3890e00b75..655ea81071ff 100644
--- a/drivers/clocksource/timer-clint.c
+++ b/drivers/clocksource/timer-clint.c
@@ -39,6 +39,7 @@ static u64 __iomem *clint_timer_cmp;
static u64 __iomem *clint_timer_val;
static unsigned long clint_timer_freq;
static unsigned int clint_timer_irq;
+static bool is_c900_clint;

#ifdef CONFIG_RISCV_M_MODE
u64 __iomem *clint_time_val;
@@ -135,6 +136,19 @@ static int clint_clock_shutdown(struct clock_event_device *evt)
return 0;
}

+static int c900_clint_clock_next_event(unsigned long delta,
+ struct clock_event_device *ce)
+{
+ void __iomem *r = clint_timer_cmp +
+ cpuid_to_hartid_map(smp_processor_id());
+ u64 val = clint_get_cycles64() + delta;
+
+ csr_set(CSR_IE, IE_TIE);
+ writel_relaxed(val, r);
+ writel_relaxed(val >> 32, r + 4);
+ return 0;
+}
+
static DEFINE_PER_CPU(struct clock_event_device, clint_clock_event) = {
.name = "clint_clockevent",
.features = CLOCK_EVT_FEAT_ONESHOT,
@@ -148,6 +162,9 @@ static int clint_timer_starting_cpu(unsigned int cpu)
{
struct clock_event_device *ce = per_cpu_ptr(&clint_clock_event, cpu);

+ if (is_c900_clint)
+ ce->set_next_event = c900_clint_clock_next_event;
+
ce->cpumask = cpumask_of(cpu);
clockevents_config_and_register(ce, clint_timer_freq, 100, ULONG_MAX);

@@ -291,5 +308,12 @@ static int __init clint_timer_init_dt(struct device_node *np)
return rc;
}

+static int __init c900_clint_timer_init_dt(struct device_node *np)
+{
+ is_c900_clint = true;
+ return clint_timer_init_dt(np);
+}
+
TIMER_OF_DECLARE(clint_timer, "riscv,clint0", clint_timer_init_dt);
TIMER_OF_DECLARE(clint_timer1, "sifive,clint0", clint_timer_init_dt);
+TIMER_OF_DECLARE(clint_timer2, "thead,c900-clint", c900_clint_timer_init_dt);