linux-kernel - Re: [RFC PATCH 19/25] kvx: power: scall poweroff driver

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Message-ID: <20230104170806.jrb6qnoyk6buzvg5@mercury.elektranox.org>
Date:   Wed, 4 Jan 2023 18:08:06 +0100
From:   Sebastian Reichel <sebastian.reichel@...labora.com>
To:     Yann Sionneau <ysionneau@...ray.eu>
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        Clement Leger <clement.leger@...tlin.com>,
        Julian Vetter <jvetter@...ray.eu>
Subject: Re: [RFC PATCH 19/25] kvx: power: scall poweroff driver

Hi,

On Tue, Jan 03, 2023 at 05:43:53PM +0100, Yann Sionneau wrote:
> Add a driver to poweroff the Coolidge SoC
> when running under Qemu, ISS or when
> the debugger (jtag-runner) runs on PL0
> to catch the scall.

line length of 41 characters is quite short.

> CC: Sebastian Reichel <sre@...nel.org>
> CC: linux-kernel@...r.kernel.org
> CC: linux-pm@...r.kernel.org
> Co-developed-by: Clement Leger <clement.leger@...tlin.com>
> Signed-off-by: Clement Leger <clement.leger@...tlin.com>
> Co-developed-by: Julian Vetter <jvetter@...ray.eu>
> Signed-off-by: Julian Vetter <jvetter@...ray.eu>
> Signed-off-by: Yann Sionneau <ysionneau@...ray.eu>
> ---
>  drivers/power/reset/kvx-scall-poweroff.c | 53 ++++++++++++++++++++++++
>  1 file changed, 53 insertions(+)
>  create mode 100644 drivers/power/reset/kvx-scall-poweroff.c
> 
> diff --git a/drivers/power/reset/kvx-scall-poweroff.c b/drivers/power/reset/kvx-scall-poweroff.c
> new file mode 100644
> index 000000000000..586d93fbcaed
> --- /dev/null
> +++ b/drivers/power/reset/kvx-scall-poweroff.c
> @@ -0,0 +1,53 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) 2017 - 2022 Kalray Inc.
> + * Author(s): Clement Leger
> + */
> +
> +#include <linux/pm.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +
> +#define SCALL_NUM_EXIT	"0xfff"
> +
> +static void kvx_scall_poweroff(void)
> +{
> +	register int status asm("r0") = 0;
> +
> +	asm volatile ("scall " SCALL_NUM_EXIT "\n\t;;"
> +		      : /* out */
> +		      : "r"(status));
> +
> +	unreachable();
> +}
> +
> +static int kvx_scall_poweroff_probe(struct platform_device *pdev)
> +{
> +	pm_power_off = kvx_scall_poweroff;
> +
> +	return 0;
> +}

Please use devm_register_power_off_handler().

-- Sebastian

> +static int kvx_scall_poweroff_remove(struct platform_device *pdev)
> +{
> +	if (pm_power_off == kvx_scall_poweroff)
> +		pm_power_off = NULL;
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id kvx_scall_poweroff_of_match[] = {
> +	{ .compatible = "kalray,kvx-scall-poweroff" },
> +	{}
> +};
> +
> +static struct platform_driver kvx_scall_poweroff_driver = {
> +	.probe = kvx_scall_poweroff_probe,
> +	.remove = kvx_scall_poweroff_remove,
> +	.driver = {
> +		.name = "kvx-scall-poweroff",
> +		.of_match_table = kvx_scall_poweroff_of_match,
> +	},
> +};
> +module_platform_driver(kvx_scall_poweroff_driver);
> -- 
> 2.37.2
> 
> 
> 
> 
> 

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