linux-kernel - Re: [PATCH 5/5] clocksource/drivers/timer-clint: Add T-Head C9xx clint support

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Message-ID: <ZgGrRrH0mxoKl90n@xhacker>
Date: Tue, 26 Mar 2024 00:50:14 +0800
From: Jisheng Zhang <jszhang@...nel.org>
To: Paul Walmsley <paul.walmsley@...ive.com>,
	Palmer Dabbelt <palmer@...belt.com>,
	Albert Ou <aou@...s.berkeley.edu>,
	Daniel Lezcano <daniel.lezcano@...aro.org>,
	Thomas Gleixner <tglx@...utronix.de>
Cc: linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 5/5] clocksource/drivers/timer-clint: Add T-Head C9xx
 clint support

On Tue, Mar 26, 2024 at 12:40:21AM +0800, Jisheng Zhang wrote:
> The mtimecmp in T-Head C9xx clint only supports 32bit read/write,
> implement such support.
> 
> Signed-off-by: Jisheng Zhang <jszhang@...nel.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 4537c77e623c..71188732e8a3 100644
> --- a/drivers/clocksource/timer-clint.c
> +++ b/drivers/clocksource/timer-clint.c
> @@ -34,6 +34,7 @@ static unsigned int clint_ipi_irq;
>  static u64 __iomem *clint_timer_cmp;
>  static unsigned long clint_timer_freq;
>  static unsigned int clint_timer_irq;
> +static bool is_c900_clint;
>  
>  #ifdef CONFIG_SMP
>  static void clint_send_ipi(unsigned int cpu)
> @@ -88,6 +89,19 @@ static int clint_clock_next_event(unsigned long delta,
>  	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,
> @@ -99,6 +113,9 @@ 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);
>  
> @@ -233,5 +250,12 @@ 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", clint_timer_init_dt);

oops, this should be "c900_clint_timer_init_dt", will update in v2.

> -- 
> 2.43.0
> 
> 
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv

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