Re: [PATCH v5 6/6] reset: Renesas RZ/N1 reboot driver

[Sebastian Reichel <sre@kernel.org>]

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Hi,

On Tue, Apr 17, 2018 at 12:04:21PM +0100, Michel Pollet wrote:
> The Renesas RZ/N1 Family (Part #R9A06G0xx) needs a small driver
> to reboot the Cortex-A7 cores. This driver is a sub driver of
> the sysctrl MFD.
> 
> Signed-off-by: Michel Pollet <michel.pollet@bp.renesas.com>
> ---
>  drivers/power/reset/Kconfig       |  7 +++
>  drivers/power/reset/Makefile      |  1 +
>  drivers/power/reset/rzn1-reboot.c | 96 +++++++++++++++++++++++++++++++++++++++
>  3 files changed, 104 insertions(+)
>  create mode 100644 drivers/power/reset/rzn1-reboot.c
> 
> diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
> index df58fc8..1416d88 100644
> --- a/drivers/power/reset/Kconfig
> +++ b/drivers/power/reset/Kconfig
> @@ -144,6 +144,13 @@ config POWER_RESET_RESTART
>  	  Instead they restart, and u-boot holds the SoC until the
>  	  user presses a key. u-boot then boots into Linux.
>  
> +config POWER_RESET_RZN1
> +	bool "Renesas RZ/N1 reboot driver"
> +	depends on ARCH_RZN1
> +	help
> +	  This driver allows rebooting the CA7 cores of the
> +	  Renesas RZ/N1 Family of SoC (Part # R9A06G0xx).
> +
>  config POWER_RESET_ST
>  	bool "ST restart driver"
>  	depends on ARCH_STI
> diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
> index 7778c74..bad9702 100644
> --- a/drivers/power/reset/Makefile
> +++ b/drivers/power/reset/Makefile
> @@ -16,6 +16,7 @@ obj-$(CONFIG_POWER_RESET_PIIX4_POWEROFF) += piix4-poweroff.o
>  obj-$(CONFIG_POWER_RESET_LTC2952) += ltc2952-poweroff.o
>  obj-$(CONFIG_POWER_RESET_QNAP) += qnap-poweroff.o
>  obj-$(CONFIG_POWER_RESET_RESTART) += restart-poweroff.o
> +obj-$(CONFIG_POWER_RESET_RZN1) += rzn1-reboot.o
>  obj-$(CONFIG_POWER_RESET_ST) += st-poweroff.o
>  obj-$(CONFIG_POWER_RESET_VERSATILE) += arm-versatile-reboot.o
>  obj-$(CONFIG_POWER_RESET_VEXPRESS) += vexpress-poweroff.o
> diff --git a/drivers/power/reset/rzn1-reboot.c b/drivers/power/reset/rzn1-reboot.c
> new file mode 100644
> index 0000000..43876d5
> --- /dev/null
> +++ b/drivers/power/reset/rzn1-reboot.c
> @@ -0,0 +1,96 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * RZ/N1 reboot driver
> + *
> + * Copyright (C) 2018 Renesas Electronics Europe Limited
> + *
> + * Michel Pollet <michel.pollet@bp.renesas.com>, <buserror@gmail.com>
> + * Derived from zx-reboot.c
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/notifier.h>
> +#include <linux/of_address.h>
> +#include <linux/platform_device.h>
> +#include <linux/reboot.h>
> +
> +/* Definitions from the SDK rzn1-sysctrl.h autogenerated file */
> +#define RZN1_SYSCTRL_REG_RSTEN_MRESET_EN		0
> +#define RZN1_SYSCTRL_REG_RSTEN_WDA7RST_EN		1
> +#define RZN1_SYSCTRL_REG_RSTEN_WDA7RST_EN_MASK		0x6
> +#define RZN1_SYSCTRL_REG_RSTEN_WDM3RST_EN		3
> +#define RZN1_SYSCTRL_REG_RSTEN_CM3LOCKUPRST_EN		4
> +#define RZN1_SYSCTRL_REG_RSTEN_CM3SYSRESET_EN		5
> +#define RZN1_SYSCTRL_REG_RSTEN_SWRST_EN			6
> +#define RZN1_SYSCTRL_REG_RSTCTRL_WDA7RST_REQ		1
> +#define RZN1_SYSCTRL_REG_RSTCTRL_WDA7RST_REQ_MASK	0x6
> +#define RZN1_SYSCTRL_REG_RSTCTRL_WDM3RST_REQ		3
> +#define RZN1_SYSCTRL_REG_RSTCTRL_CM3LOCKUPRST_REQ	4
> +#define RZN1_SYSCTRL_REG_RSTCTRL_CM3SYSRESET_REQ	5
> +#define RZN1_SYSCTRL_REG_RSTCTRL_SWRST_REQ		6
> +
> +static void __iomem *reg_rsten, *reg_rstctrl;

Please make this into a proper driver and allocate this dynamically.
You can get device context from the notifier_block, see for example
gpio-restart.

> +static int rzn1_reboot_handler(struct notifier_block *this,
> +			      unsigned long mode, void *cmd)
> +{
> +	writel(readl(reg_rsten) |
> +			BIT(RZN1_SYSCTRL_REG_RSTEN_SWRST_EN) |
> +			BIT(RZN1_SYSCTRL_REG_RSTEN_MRESET_EN),
> +		reg_rsten);
> +	writel(readl(reg_rstctrl) |
> +			BIT(RZN1_SYSCTRL_REG_RSTCTRL_SWRST_REQ),
> +		reg_rstctrl);
> +
> +	mdelay(50);
> +	pr_emerg("Unable to restart system\n");
> +
> +	return NOTIFY_DONE;
> +}
> +
> +static struct notifier_block rzn1_reboot_nb = {
> +	.notifier_call = rzn1_reboot_handler,
> +	.priority = 128,
> +};
> +
> +static int rzn1_reboot_probe(struct platform_device *ofdev)
> +{
> +	int err;
> +
> +	reg_rsten = of_iomap(ofdev->dev.of_node, 0);
> +	reg_rstctrl = of_iomap(ofdev->dev.of_node, 1);

Please use devm_ioremap().

> +
> +	if (!reg_rsten || !reg_rstctrl) {
> +		dev_err(&ofdev->dev, "invalid register mapping\n");
> +		return -ENODEV;
> +	}
> +
> +	err = register_restart_handler(&rzn1_reboot_nb);
> +	if (err) {
> +		dev_err(&ofdev->dev, "register restart handler failed(err=%d)\n",
> +			err);
> +	}

Missing unregister_restart_handler() in .remove.

> +
> +	return err;
> +}
> +
> +static const struct of_device_id rzn1_reboot_of_match[] = {
> +	{ .compatible = "renesas,rzn1-reboot" },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, rzn1_reboot_of_match);
> +
> +static struct platform_driver rzn1_reboot_driver = {
> +	.probe = rzn1_reboot_probe,
> +	.driver = {
> +		.name = "rzn1-reboot",
> +		.of_match_table = rzn1_reboot_of_match,
> +	},
> +};
> +module_platform_driver(rzn1_reboot_driver);
> +
> +MODULE_DESCRIPTION("RZ/N1 reboot driver");
> +MODULE_AUTHOR("Michel Pollet <michel.pollet@bp.renesas.com>, <buserror@gmail.com>");
> +MODULE_LICENSE("GPL v2");

-- Sebastian

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