clocksource/drivers/timer-riscv: Clear timer interrupt on timer initialization

[ Upstream commit 8248ca30ef89f9cc74ace62ae1b9a22b5f16736c ]

In the RISC-V specification, the stimecmp register doesn't have a default
value. To prevent the timer interrupt from being triggered during timer
initialization, clear the timer interrupt by writing stimecmp with a
maximum value.

Fixes: 9f7a8ff6391f ("RISC-V: Prefer sstc extension if available")
Cc: <stable@vger.kernel.org>
Signed-off-by: Ley Foon Tan <leyfoon.tan@starfivetech.com>
Reviewed-by: Samuel Holland <samuel.holland@sifive.com>
Tested-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20240306172330.255844-1-leyfoon.tan@starfivetech.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/clocksource/timer-riscv.c b/drivers/clocksource/timer-riscv.c
index 57857c0dfba97e0bfdcd5190e8aee31e11028667..1c732479a2c8d482b1cedb13edb565219ba0e9f2 100644 (file)
--- a/drivers/clocksource/timer-riscv.c
+++ b/drivers/clocksource/timer-riscv.c
@@ -101,6 +101,9 @@ static int riscv_timer_starting_cpu(unsigned int cpu)
 {
        struct clock_event_device *ce = per_cpu_ptr(&riscv_clock_event, cpu);
 
+       /* Clear timer interrupt */
+       riscv_clock_event_stop();
+
        ce->cpumask = cpumask_of(cpu);
        ce->irq = riscv_clock_event_irq;
        if (riscv_timer_cannot_wake_cpu)