linux-kernel - [PATCH 03/12] power: reset: Add TI-SCI reboot driver

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Message-ID: <20240131221957.213717-4-afd@ti.com>
Date: Wed, 31 Jan 2024 16:19:48 -0600
From: Andrew Davis <afd@...com>
To: Nishanth Menon <nm@...com>, Tero Kristo <kristo@...nel.org>,
        Santosh
 Shilimkar <ssantosh@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof
 Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley
	<conor+dt@...nel.org>,
        Sebastian Reichel <sre@...nel.org>,
        Vignesh
 Raghavendra <vigneshr@...com>
CC: <linux-arm-kernel@...ts.infradead.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <linux-pm@...r.kernel.org>,
        Andrew Davis
	<afd@...com>
Subject: [PATCH 03/12] power: reset: Add TI-SCI reboot driver

This reboot driver calls into firmware using TI-SCI to reboot the system.
We register the handler with low priority as we want PSCI to remain the
main way these devices are rebooted. This driver acts as a fallback if
PSCI is not able to reboot the system.

Signed-off-by: Andrew Davis <afd@...com>
---
 MAINTAINERS                         |  1 +
 drivers/power/reset/Kconfig         |  7 ++++
 drivers/power/reset/Makefile        |  1 +
 drivers/power/reset/ti-sci-reboot.c | 63 +++++++++++++++++++++++++++++
 4 files changed, 72 insertions(+)
 create mode 100644 drivers/power/reset/ti-sci-reboot.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 45983bb174fe4..ee67ea497fc56 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -21758,6 +21758,7 @@ F:	drivers/clk/keystone/sci-clk.c
 F:	drivers/firmware/ti_sci*
 F:	drivers/irqchip/irq-ti-sci-inta.c
 F:	drivers/irqchip/irq-ti-sci-intr.c
+F:	drivers/power/reset/ti-sci-reboot.c
 F:	drivers/reset/reset-ti-sci.c
 F:	drivers/soc/ti/ti_sci_inta_msi.c
 F:	drivers/pmdomain/ti/ti_sci_pm_domains.c
diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
index fece990af4a75..d3e91e54cae24 100644
--- a/drivers/power/reset/Kconfig
+++ b/drivers/power/reset/Kconfig
@@ -205,6 +205,13 @@ config POWER_RESET_ST
 	help
 	  Reset support for STMicroelectronics boards.
 
+config POWER_RESET_TI_SCI
+	tristate "TI System Control Interface (TI-SCI) reboot driver"
+	depends on TI_SCI_PROTOCOL
+	help
+	  This enables the reboot driver support over TI System Control
+	  Interface available on some TI's SoCs.
+
 config POWER_RESET_TPS65086
 	bool "TPS65086 restart driver"
 	depends on MFD_TPS65086
diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
index a95d1bd275d18..881ca58a43b9c 100644
--- a/drivers/power/reset/Makefile
+++ b/drivers/power/reset/Makefile
@@ -23,6 +23,7 @@ obj-$(CONFIG_POWER_RESET_QNAP) += qnap-poweroff.o
 obj-$(CONFIG_POWER_RESET_REGULATOR) += regulator-poweroff.o
 obj-$(CONFIG_POWER_RESET_RESTART) += restart-poweroff.o
 obj-$(CONFIG_POWER_RESET_ST) += st-poweroff.o
+obj-$(CONFIG_POWER_RESET_TI_SCI) += ti-sci-reboot.o
 obj-$(CONFIG_POWER_RESET_TPS65086) += tps65086-restart.o
 obj-$(CONFIG_POWER_RESET_VERSATILE) += arm-versatile-reboot.o
 obj-$(CONFIG_POWER_RESET_VEXPRESS) += vexpress-poweroff.o
diff --git a/drivers/power/reset/ti-sci-reboot.c b/drivers/power/reset/ti-sci-reboot.c
new file mode 100644
index 0000000000000..400bd5d740f8b
--- /dev/null
+++ b/drivers/power/reset/ti-sci-reboot.c
@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Texas Instrument's System Control Interface (TI-SCI) reboot driver
+ *
+ * Copyright (C) 2024 Texas Instruments Incorporated - https://www.ti.com/
+ *	Andrew Davis <afd@...com>
+ */
+
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+
+#include <linux/soc/ti/ti_sci_protocol.h>
+
+static int ti_sci_reboot_handler(struct sys_off_data *data)
+{
+	const struct ti_sci_handle *sci = data->cb_data;
+	const struct ti_sci_core_ops *core_ops = &sci->ops.core_ops;
+
+	core_ops->reboot_device(sci);
+
+	return NOTIFY_DONE;
+}
+
+static int ti_sci_reboot_probe(struct platform_device *pdev)
+{
+	const struct ti_sci_handle *sci;
+	int err;
+
+	sci = devm_ti_sci_get_handle(&pdev->dev);
+	if (IS_ERR(sci))
+		return PTR_ERR(sci);
+
+	err = devm_register_sys_off_handler(&pdev->dev,
+					    SYS_OFF_MODE_RESTART,
+					    SYS_OFF_PRIO_LOW,
+					    ti_sci_reboot_handler,
+					    (void *)sci);
+	if (err)
+		return dev_err_probe(&pdev->dev, err, "Cannot register restart handler\n");
+
+	return 0;
+}
+
+static const struct of_device_id ti_sci_reboot_of_match[] = {
+	{ .compatible = "ti,sci-reboot", },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, ti_sci_reboot_of_match);
+
+static struct platform_driver ti_sci_reboot_driver = {
+	.probe = ti_sci_reboot_probe,
+	.driver = {
+		.name = "ti-sci-reboot",
+		.of_match_table = ti_sci_reboot_of_match,
+	},
+};
+module_platform_driver(ti_sci_reboot_driver);
+
+MODULE_AUTHOR("Andrew Davis <afd@...com>");
+MODULE_DESCRIPTION("TI System Control Interface (TI SCI) Reboot driver");
+MODULE_LICENSE("GPL");
-- 
2.39.2