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-rw-r--r--drivers/reset/Kconfig11
-rw-r--r--drivers/reset/Makefile1
-rw-r--r--drivers/reset/reset-scmi.c124
3 files changed, 136 insertions, 0 deletions
diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index 6d5d76db55b0..7b07281aa0ae 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -116,6 +116,17 @@ config RESET_QCOM_PDC
to control reset signals provided by PDC for Modem, Compute,
Display, GPU, Debug, AOP, Sensors, Audio, SP and APPS.
+config RESET_SCMI
+ tristate "Reset driver controlled via ARM SCMI interface"
+ depends on ARM_SCMI_PROTOCOL || COMPILE_TEST
+ default ARM_SCMI_PROTOCOL
+ help
+ This driver provides support for reset signal/domains that are
+ controlled by firmware that implements the SCMI interface.
+
+ This driver uses SCMI Message Protocol to interact with the
+ firmware controlling all the reset signals.
+
config RESET_SIMPLE
bool "Simple Reset Controller Driver" if COMPILE_TEST
default ARCH_STM32 || ARCH_STRATIX10 || ARCH_SUNXI || ARCH_ZX || ARCH_ASPEED || ARCH_BITMAIN || ARC
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index 61456b8f659c..cf60ce526064 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -18,6 +18,7 @@ obj-$(CONFIG_RESET_OXNAS) += reset-oxnas.o
obj-$(CONFIG_RESET_PISTACHIO) += reset-pistachio.o
obj-$(CONFIG_RESET_QCOM_AOSS) += reset-qcom-aoss.o
obj-$(CONFIG_RESET_QCOM_PDC) += reset-qcom-pdc.o
+obj-$(CONFIG_RESET_SCMI) += reset-scmi.o
obj-$(CONFIG_RESET_SIMPLE) += reset-simple.o
obj-$(CONFIG_RESET_STM32MP157) += reset-stm32mp1.o
obj-$(CONFIG_RESET_SOCFPGA) += reset-socfpga.o
diff --git a/drivers/reset/reset-scmi.c b/drivers/reset/reset-scmi.c
new file mode 100644
index 000000000000..c6d3c8427f14
--- /dev/null
+++ b/drivers/reset/reset-scmi.c
@@ -0,0 +1,124 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ARM System Control and Management Interface (ARM SCMI) reset driver
+ *
+ * Copyright (C) 2019 ARM Ltd.
+ */
+
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/device.h>
+#include <linux/reset-controller.h>
+#include <linux/scmi_protocol.h>
+
+/**
+ * struct scmi_reset_data - reset controller information structure
+ * @rcdev: reset controller entity
+ * @handle: ARM SCMI handle used for communication with system controller
+ */
+struct scmi_reset_data {
+ struct reset_controller_dev rcdev;
+ const struct scmi_handle *handle;
+};
+
+#define to_scmi_reset_data(p) container_of((p), struct scmi_reset_data, rcdev)
+#define to_scmi_handle(p) (to_scmi_reset_data(p)->handle)
+
+/**
+ * scmi_reset_assert() - assert device reset
+ * @rcdev: reset controller entity
+ * @id: ID of the reset to be asserted
+ *
+ * This function implements the reset driver op to assert a device's reset
+ * using the ARM SCMI protocol.
+ *
+ * Return: 0 for successful request, else a corresponding error value
+ */
+static int
+scmi_reset_assert(struct reset_controller_dev *rcdev, unsigned long id)
+{
+ const struct scmi_handle *handle = to_scmi_handle(rcdev);
+
+ return handle->reset_ops->assert(handle, id);
+}
+
+/**
+ * scmi_reset_deassert() - deassert device reset
+ * @rcdev: reset controller entity
+ * @id: ID of the reset to be deasserted
+ *
+ * This function implements the reset driver op to deassert a device's reset
+ * using the ARM SCMI protocol.
+ *
+ * Return: 0 for successful request, else a corresponding error value
+ */
+static int
+scmi_reset_deassert(struct reset_controller_dev *rcdev, unsigned long id)
+{
+ const struct scmi_handle *handle = to_scmi_handle(rcdev);
+
+ return handle->reset_ops->deassert(handle, id);
+}
+
+/**
+ * scmi_reset_reset() - reset the device
+ * @rcdev: reset controller entity
+ * @id: ID of the reset signal to be reset(assert + deassert)
+ *
+ * This function implements the reset driver op to trigger a device's
+ * reset signal using the ARM SCMI protocol.
+ *
+ * Return: 0 for successful request, else a corresponding error value
+ */
+static int
+scmi_reset_reset(struct reset_controller_dev *rcdev, unsigned long id)
+{
+ const struct scmi_handle *handle = to_scmi_handle(rcdev);
+
+ return handle->reset_ops->reset(handle, id);
+}
+
+static const struct reset_control_ops scmi_reset_ops = {
+ .assert = scmi_reset_assert,
+ .deassert = scmi_reset_deassert,
+ .reset = scmi_reset_reset,
+};
+
+static int scmi_reset_probe(struct scmi_device *sdev)
+{
+ struct scmi_reset_data *data;
+ struct device *dev = &sdev->dev;
+ struct device_node *np = dev->of_node;
+ const struct scmi_handle *handle = sdev->handle;
+
+ if (!handle || !handle->reset_ops)
+ return -ENODEV;
+
+ data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ data->rcdev.ops = &scmi_reset_ops;
+ data->rcdev.owner = THIS_MODULE;
+ data->rcdev.of_node = np;
+ data->rcdev.nr_resets = handle->reset_ops->num_domains_get(handle);
+
+ return devm_reset_controller_register(dev, &data->rcdev);
+}
+
+static const struct scmi_device_id scmi_id_table[] = {
+ { SCMI_PROTOCOL_RESET },
+ { },
+};
+MODULE_DEVICE_TABLE(scmi, scmi_id_table);
+
+static struct scmi_driver scmi_reset_driver = {
+ .name = "scmi-reset",
+ .probe = scmi_reset_probe,
+ .id_table = scmi_id_table,
+};
+module_scmi_driver(scmi_reset_driver);
+
+MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
+MODULE_DESCRIPTION("ARM SCMI reset controller driver");
+MODULE_LICENSE("GPL v2");