Re: [PATCH V3 17/20] RISC-V: time.c: Add ACPI support for time_init()

From: Conor Dooley <conor@kernel.org>
To: Sunil V L <sunilvl@ventanamicro.com>
Cc: linux-riscv@lists.infradead.org, linux-acpi@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	"Rafael J . Wysocki" <rafael@kernel.org>,
	Len Brown <lenb@kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
	Marc Zyngier <maz@kernel.org>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	Jonathan Corbet <corbet@lwn.net>,
	Anup Patel <apatel@ventanamicro.com>,
	Andrew Jones <ajones@ventanamicro.com>,
	Atish Patra <atishp@rivosinc.com>,
	'Conor Dooley ' <conor.dooley@microchip.com>,
	"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>
Subject: Re: [PATCH V3 17/20] RISC-V: time.c: Add ACPI support for time_init()
Date: Mon, 6 Mar 2023 21:09:11 +0000	[thread overview]
Message-ID: <0cceafc3-522b-4ce0-9016-e931c818adec@spud> (raw)
In-Reply-To: <20230303133647.845095-18-sunilvl@ventanamicro.com>

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On Fri, Mar 03, 2023 at 07:06:44PM +0530, Sunil V L wrote:
> On ACPI based platforms, timer related information is
> available in RHCT. Add ACPI based probe support to the
> timer initialization.
> 
> Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
> ---
>  arch/riscv/kernel/time.c | 23 +++++++++++++++++------
>  1 file changed, 17 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/riscv/kernel/time.c b/arch/riscv/kernel/time.c
> index babaf3b48ba8..2c29543549c3 100644
> --- a/arch/riscv/kernel/time.c
> +++ b/arch/riscv/kernel/time.c
> @@ -4,6 +4,7 @@
>   * Copyright (C) 2017 SiFive
>   */
>  
> +#include <linux/acpi.h>
>  #include <linux/of_clk.h>
>  #include <linux/clockchips.h>
>  #include <linux/clocksource.h>
> @@ -18,17 +19,27 @@ EXPORT_SYMBOL_GPL(riscv_timebase);
>  void __init time_init(void)
>  {
>  	struct device_node *cpu;
> +	struct acpi_table_rhct *rhct;
> +	acpi_status status;
>  	u32 prop;
>  
> -	cpu = of_find_node_by_path("/cpus");
> -	if (!cpu || of_property_read_u32(cpu, "timebase-frequency", &prop))
> -		panic(KERN_WARNING "RISC-V system with no 'timebase-frequency' in DTS\n");
> -	of_node_put(cpu);
> -	riscv_timebase = prop;
> +	if (acpi_disabled) {
> +		cpu = of_find_node_by_path("/cpus");
> +		if (!cpu || of_property_read_u32(cpu, "timebase-frequency", &prop))
> +			panic("RISC-V system with no 'timebase-frequency' in DTS\n");

I appreciate that it was like this before, but a newline here (and in
the corresponding spot below) would be nice.
That's a minor nit though, so:
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>

Thanks,
Conor.

> +		of_node_put(cpu);
> +		riscv_timebase = prop;
> +		of_clk_init(NULL);
> +	} else {
> +		status = acpi_get_table(ACPI_SIG_RHCT, 0, (struct acpi_table_header **)&rhct);
> +		if (ACPI_FAILURE(status))
> +			panic("RISC-V ACPI system with no RHCT table\n");
> +		riscv_timebase = rhct->time_base_freq;
> +		acpi_put_table((struct acpi_table_header *)rhct);
> +	}
>  
>  	lpj_fine = riscv_timebase / HZ;
>  
> -	of_clk_init(NULL);
>  	timer_probe();
>  
>  	tick_setup_hrtimer_broadcast();
> -- 
> 2.34.1
> 

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